U.S. flag

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

  • Publications
  • Account settings
  • Advanced Search
  • Journal List
  • Medicina (Kaunas)

Logo of medicina

CT Urography Findings of Upper Urinary Tract Carcinoma and Its Mimickers: A Pictorial Review

Paola martingano.

1 Department of Radiology, ASUGI, Cattinara Hospital, 34139 Trieste, Italy

Marco F. M. Cavallaro

2 Department of Radiology, ASUGI, Maggiore Hospital, 34129 Trieste, Italy; [email protected]

Alessandro M. Bozzato

3 Department of Radiology, University of Trieste, ASUGI, Cattinara Hospital, 34139 Trieste, Italy; [email protected] (A.M.B.); [email protected] (E.B.); [email protected] (M.A.C.)

Elisa Baratella

Maria a. cova.

Urothelial carcinoma (UC) is the fourth most frequent tumor in Western countries and upper tract urothelial carcinoma (UTUC), affecting pyelocaliceal cavities and ureter, accounts for 5–10% of all UCs. Computed tomography urography (CTU) is now considered the imaging modality of choice for diagnosis and staging of UTUC, guiding disease management. Although its specificity is very high, both benign and malignant diseases could mimic UTUCs and therefore have to be well-known to avoid misdiagnosis. We describe CTU findings of upper urinary tract carcinoma, features that influence disease management, and possible differential diagnosis.

1. Introduction

Urothelial carcinoma (UC) is the fourth most frequent malignancy in Western countries, with a peak incidence in elderly (70 to 90-year-olds) and a three-fold man prevalence. Upper tract urothelial carcinoma (UTUC) accounts for 5–10% of all UCs [ 1 , 2 ], with double the incidence of pyelocaliceal tumors compared to ureter location. UTUCs are often associated with concomitant or recurrent bladder cancer, while the contralateral urinary tract is implicated only in 2–6% of tumors. Many risk factors have been identified in the development of UCs, in particular tobacco smoking, some herb consumption, and aromatic amines occupational exposure [ 3 ].

Local symptoms of UTUCs, represented by flank pain or lumbar mass, are usually due to advanced disease, while systemic symptoms like fatigue, fever, and weight loss are related to metastatic progression. Hematuria, either microscopic or visible, is the most common and early symptom of UC, and requires prompt investigation. In patient with positive cytology but negative bladder cystoscopy, a UTUC is highly suspected, and so an upper tract evaluation is needed. Flexible ureteroscopy allows direct visualization of ureter, renal pelvis, and collecting system, with the possibility of direct biopsy or aspiration cytology, but it is considered quite invasive. Among imaging techniques, computed tomography urography (CTU) offers the highest accuracy in UTUC diagnosis, with a pooled sensitivity of 92% and a pooled specificity of 95% [ 3 , 4 ]. Other imaging modalities, like magnetic resonance urography (MRU) have been tested, but have been proven to be inferior. In particular, the direct comparison of MRU and CTU showed a sensibility of 82.8–86.2% and a specificity of 83.1–83.3% for MRU compared to 96.6% and 87–91.5% of CTU, respectively [ 5 ], so present guidelines indicate CTU as the imaging of choice in the work up of hematuria [ 3 ].

2. CTU Technique

CT Urography has to be tailored to clinical indication and could be performed with different protocols, including at least an excretory phase [ 6 ]. An unenhanced phase is used to detect stones, calcifications, hemorrhages, clots, and to measure the attenuation coefficients of the renal and urothelial masses [ 7 , 8 , 9 ]. A corticomedullary phase, occurring between 30 and 40 s after contrast medium administration, is used to evaluate suspected vascular abnormalities or arterial enhancement [ 9 , 10 ], while a nephrographic phase, acquired 90–110 s after contrast medium administration, improves detection and characterization of renal lesions [ 9 , 11 ]. The excretory phase, obtained 8–12 min after contrast agent administration, assesses the abnormalities of the urothelium with the distension and the opacification of the collecting systems, ureters and bladder [ 8 , 9 , 10 , 11 , 12 ]. However, the main limitation of a multiphasic protocols is the high radiation exposure, ranging from 25–35 mSv [ 6 ]. To reduce radiation dose, a split-bolus injection of contrast medium could be used, obtaining a single combined nephrographic-excretory phase, lowering the effective dose to 17.5 mSv [ 13 ]. To improve the distension and opacification of the collecting system, different ancillary maneuvers can be employed, the most common being intravenous saline hydration and low-dose furosemide injection ( Figure 1 ) [ 6 ].

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g001.jpg

Computed tomography urography (CTU): MIP (maximum intensity projection) ( a ) and coronal ( b ) images. Furosemide administration allows distention of the entire urinary tract, without blooming artifacts due to high attenuation of intraluminal contrast medium; the split-bolus technique allows simultaneous luminal and parenchymal assessment.

3. Imaging Findings

Upper tract urothelial cell carcinomas appear on unenhanced phase as soft tissue masses, with lower density than renal calculi, except for indinavir ones [ 9 , 14 , 15 , 16 ]; intralesional and superficial calcifications can be seen and may appear granular, linear, or punctate [ 14 , 17 , 18 , 19 , 20 ]. After contrast medium administration, UTUCs show early enhancement, unlike non-enhancing clots, while in the excretory phase, they appear as filling defects or luminal narrowing in the urinary tract, best appreciated using a wide window setting, because small tumors may be concealed by the high attenuation of surrounding contrast medium ( Figure 2 ) [ 9 , 14 , 15 , 16 ].

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g002.jpg

Small renal pelvis UTUC: a soft tissue lesion on unenhanced scan (arrow in ( a )), shows homogeneous enhancement in the cortico-medullary phase (arrow in ( b )) and appears as a filling defect in the nephrographic-excretory phase using a wide window setting (arrow in ( c )). With wrong imaging settings, it results hardly recognizable ( d ).

Based on their morphology UTUCs may be differentiated in papillary tumors, flat lesions, and invasive carcinomas. Papillary tumors appear on CTU as single or multiple filling defects in the collecting system, varying from millimetric to broad basis wide tumors occupying the entire lumen [ 14 , 16 , 17 ]. When tumors involve the caliceal system, a calyx could be entirely missing in the excretory phase due to complete filling by solid tissue, the so-called “oncocalyx”( Figure 3 a); calyx dilation and absence of urine opacification, classically described as “phantom calyx”, occur if tumor develops in the infundibular neck determining its amputation ( Figure 3 b) [ 15 , 17 , 21 , 22 ]. When tumors involve the ureter, lumen occlusion is frequent and hydronephrosis can cause hypoperfusion of the renal parenchyma; on CTU, the solid ureteral mass is accompanied by a reduced nephrographic effect and a delayed contrast agent excretion ( Figure 4 ) [ 16 , 17 ]. Flat lesions could manifest as a concentric or eccentric pyelocaliceal or ureteral wall thickening, not invariably causing luminal narrowing ( Figure 5 ). Finally, UTUCs can present an infiltrative pattern with increased attenuation and stranding of periureteral and renal sinus fat ( Figure 6 ). Direct involvement of renal parenchyma may be present in pyelocaliceal malignancy; on CTU, it is easily appreciated in the cortico-medullary phase thanks to early UC enhancement compared to renal medulla, while in the nephrographic phase, tumor tissue hypoenhancement is more difficult to differentiate from reduced nephrographic effect of the compressed adjacent parenchyma ( Figure 7 ). Sometimes, in advanced cases, infiltration causes kidney enlargement, but with the preservation of the organ shape [ 9 , 16 ].

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g003.jpg

Pyelocaliceal papillary tumors: coronal nephrographic-excretory images ( a , b ). Solid tissue enlarges and obscures the superior calyx (arrow in ( a )), the so-called oncocalyx. Solid pelvic-infundibular tissue (empty arrow in ( b )) causes upstream non-opacified dilation (*), the so-called phantom calyx.

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g004.jpg

Ureteral papillary upper tract urothelial carcinoma (UTUC): nephrographic-excretory coronal ( a ) and axial ( b ) images. Solid tissue in the lumbar ureter (empty arrow in ( a )) determines complete occlusion of the urinary tract with hydronephrosis. Note the reduced nephrographic effect and absent excretion of contrast medium in the left kidney.

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g005.jpg

Flat ureteral UTUC: nephrographic-excretory axial ( a ) and CPR—curved planar reconstruction—coronal ( b ) images. An irregular wall thickening (arrows), without lumen narrowing, extends in the upper ureter. Urinary stones are visible in inferior calyces.

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g006.jpg

Pyelocaliceal infiltrative UTUC: nephrographic-excretory axial ( a ) and coronal ( b ) images. Extensive pyelocaliceal wall thickening with lumen narrowing causes diffused attenuation of the renal sinus fat due to tumoral infiltration (empty arrows).

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g007.jpg

Caliceal infiltrative UTUC: coronal cortico-medullary ( a ) and nephrographic-excretory ( b ) images. Solid tissue occupies upper and medium calyces (*); the direct infiltration of kidney parenchyma appears hyper-enhancing compared to medulla in the cortico-medullary phase (arrow in ( a )) and shows wash out in the nephrographic phase (arrow in ( b )).

CTU findings help distinguishing organ-confined diseases from advanced ones, but infiltrative tumors are correctly diagnosed only in 67% of cases; this low performance is due to microscopic invasion, not visible at imaging, or to misinterpretation of inflammatory changes as tumor involvement [ 23 ]. Therefore, in clinical practice multiple clinical, histological, and imaging parameters are used to stratify tumor risk and its consequent management. According to European Association of Urology guidelines, low-risk tumors, identified by unifocal disease, size < 2 cm, non-invasive aspect on CTU, and low-grade on cytologic or biopsy specimens, could be treated with kidney-sparing surgery (endoscopic ablation and segmental ureteral resection); on the other hand radical nephroureterectomy and systemic chemotherapy are indicated in case of multifocal disease, size > 2 cm, invasive aspect on CTU, concomitant hydronephrosis, high-grade cytology, high grade or variant histology, or previous cystectomy [ 3 ].

4. Mimickers of UTUC

Many pathological conditions may mimic CTU appearance of UTUC, both benign and malignant. Some CTU features could help differential diagnosis, but they are not always sufficient and so further diagnostic work-up may be required. Among these lesions, hypertrophied papilla, clots, suburothelial hemorrhage, renal papillary necrosis, symmetric wall thickening of the urinary tract due to inflammation or encasement, cystic pyeloureteritis, urogenital tuberculosis, and fibroepithelial polyp are benign lesions that should be considered to avoid an unjustified invasive intervention. On the other hand, renal cell carcinoma and renal lymphoma may be mistaken for UTUC and receive incorrect treatment.

4.1. Hypertrophied Papilla

Hypertrophied papilla, a benign anatomical abnormality, causes a pronounced concave impression on surrounding calyx that can mimic a filling defect in the excretory phase. The presence of a smooth contour with preservation of forniceal shape ( Figure 8 ), along with the frequent presence of multiple similar aspects in the same kidney, allows correct diagnosis [ 24 , 25 ].

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g008.jpg

Hypertrophied papilla: nephrographic-excretory coronal ( a ), sagittal ( b ) and axial ( c ) images. A filling defect with smooth margins and regular shape is recognizable in the superior calyx (arrows); the forniceal structure is preserved.

4.2. Blood Clots

Blood clots are usually caused by trauma, neoplasm, renal lithiasis and anticoagulant therapy. They commonly manifest as slightly hyperdense lesions on unenhanced phase, without enhancement after contrast medium administration; in the excretory phase, they can be more easily differentiated from UTUC, because commonly entirely surrounded by opacified urine ( Figure 9 ). In doubtful cases a further CT scan performed after changing patient position demonstrates a shift of the suspicious filling defect [ 7 , 9 , 12 ].

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g009.jpg

Blood clot: nephrographic-excretory axial ( a ), coronal ( b ) and sagittal ( c ) images. A small filling defect in the superior calyx without contact with the caliceal wall.

4.3. Suburothelial Hemorrhage

Suburothelial hemorrhage is a rare condition with diffuse renal sinus wall thickening due to intraparietal bleeding, presenting with flank pain and hematuria. This condition is related to bleeding diatheses such as anticoagulant treatment and hematological disorders. In the contrast enhanced and excretory phases, the renal pelvic wall shows diffuse soft tissue thickening with lumen narrowing, easily mistaken for a UTUC. The unenhanced phase allows the correct differential diagnosis demonstrating hyperdensity of the urinary tract wall due to hemorrhagic components ( Figure 10 ) [ 26 , 27 ].

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g010.jpg

Suburothelial hemorrhage: axial images. In the unenhanced scan ( a ) diffuse hyperdense urothelial wall thickening is clearly visible. In the nephrographic ( b ) and excretory ( c ) phases wall thickening is hardly differentiable from a UTUC. Complete disease resolution on follow up CTU ( d ) confirmed the benign nature of previous extensive urothelial thickening.

4.4. Renal Papillary Necrosis

Renal papillary necrosis (RPN), often presenting with hematuria, is due to an ischemic lesion involving the renal papilla; it is frequently associated with diabetes mellitus, sickle cell anemia, analgesic abuse and urinary tract infections [ 11 ]. RPN is recognizable only in the excretory phase, presenting as central erosion of the papilla filled with opacified urine, the teardrop-shaped cavity ( Figure 11 a) or the “ball-on-tee” sign ( Figure 11 b), or as erosion of the calyceal fornices filled with opacified urine, the “lobster-claw calyx”. In the end stage, the sloughed necrotic papilla appears as a non-enhancing filling defect surrounded by contrast medium in the excavated calyx, the signet ring sing ( Figure 11 c) [ 14 , 25 ]. Beyond the possible presentation, RPN determines caliceal irregularity extending proximal to interpapillary line, with opacified urine located deep into the medulla, while calyceal irregularities due to UTUC extend toward renal pelvis [ 19 ].

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g011.jpg

Renal papillary necrosis: excretory coronal images. The central erosion of a papilla appears as a focal spot of opacified urine inside renal medulla, with a teardrop shape (arrow in ( a )) and a ball-on-tee shape (arrow in ( b )); in the end stage necrotic papilla creates a filling defect in the excavated calyx, the signet ring sign (arrow in ( c )).

4.5. Inflammation

Pyeloureteral wall thickening with increased attenuation of the surrounding fat is not a specific sign of UTUC but may be present also with urothelial inflammatory diseases. Differential diagnosis is not always possible on the basis of imaging alone, and so clinical, laboratory, and, sometimes, pathological findings have to be considered to decide proper management. The involvement of a longer part of the urinary tract is usually related to a benign disease, while UTUC is often associated with a shorter segment localization [ 7 , 12 ]. Other signs indicative of a benign disease are circumferential symmetric wall thickening, with diffuse urothelial enhancement, smooth margins, and symmetric and homogeneous attenuation of the surrounding fat ( Figure 12 ); moreover, in doubtful cases, a follow-up CT may be useful to confirm benign nature of urothelial thickening ( Figure 13 ) [ 28 , 29 ].

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g012.jpg

Inflammatory disease: CPR cortico-medullary images in corona ( a ) and sagittal ( b ) planes. Diffuse urothelial thickening with homogenous enhancement associated to haziness of sinus fat and mild hydronephrosis.

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g013.jpg

Inflammatory disease. Nephrographic-excretory CPR ( a , c ) and axial ( b , d ) images. A short ureteral wall thickening, with smooth margins and symmetric appearance, causes mild lumen stricture (arrows in ( a , b )); clinical and laboratory data are indicative of an inflammatory disease. The follow up CTU performed 3 months later ( c , d ), demonstrates a complete resolution, confirming the benign nature.

4.6. Retroperitoneal Fibrosis

Retroperitoneal fibrosis (RF) is a fibro-inflammatory disease characterized by the development of fibrotic tissue in the retroperitoneum; it could be idiopathic, associated to abdominal aortic aneurism, or secondary to other diseases. RF can cause ureteral encasement with obstruction and hydronephrosis. On CT it appears as enhancing solid tissue, generally isodense to muscle, that develops around the abdominal aorta, causing obscuration of fat planes, and medial displacement of the ureters ( Figure 14 ) [ 29 ].

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g014.jpg

Retroperitoneal fibrosis. Nephrographic axial ( a ) and coronal ( b , c ) images. Low enhancing solid tissue surround an aneurismatic abdominal aorta, causing encasement and medial deviation with narrowing of both ureters (arrows), already treated with ureteral stents.

4.7. Pyeloureteritis Cystica

Pyeloureteritis cystica is a benign disease due to chronic inflammation of the urinary tract, characterized by multiple subepithelial cysts, arising from degeneration of von Brunn’s nests. On unenhanced phase, the measurement of the attenuation coefficients of the cysts is usually not possible due to their tiny dimensions and, on excretory phase, they appear as multiple millimetric filling defects, often not detectable on nephrographic phase ( Figure 15 ). The differential diagnosis between pyeloureteritis cystica and multifocal UTUC may be difficult. Nevertheless, the latter is usually characterized by presence of fewer and more inhomogeneous lesions [ 7 , 12 , 29 , 30 ].

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g015.jpg

Pyeloureteritis cystica: ascending pyelography ( a ) and CT nephrographic coronal CT ( b ) images. Multiple small and regular filling defects are recognizable in the renal pelvis and proximal ureter (arrows in ( a )), which correspond to tiny hypodense lesions inside a diffuse enhancing urothelial wall thickening (arrows in ( b )).

4.8. Urogenital Tuberculosis

Urogenital tuberculosis (UGTB) accounts for almost one third of extrapulmonary TB cases, and 3% of patients with TB develop renal manifestations [ 31 ]. In the early stage of UGTB, the most typical imaging findings are papillitis, papillary necrosis and caliceal deformity, the so-called moth-eaten calyx [ 12 , 22 , 32 ]. During progression of the disease, granulomas coalesce and form the tuberculomas, i.e., caseous necrotic lesions with hypodense non-enhancing center, in direct communication with calyces [ 12 ]. At this stage, a fibrotic response develops, causing strictures with caliectasis, or amputation of the calyces, both characterized by a typical “rose-thorn” shape [ 12 , 22 , 31 ]. Moreover, pelvic stricture and retraction may be seen along with an irregular thickening of the pelvis and the ureter [ 22 , 33 ]. The differential diagnosis between UGTB and UTUC may be difficult. However, UGTB must be highly suspected when multiple different caliceal deformities coexist in the same patient ( Figure 16 ) [ 28 ].

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g016.jpg

Urogenital tuberculosis: nephrographic-excretory CPR ( a ), coronal ( b ) and sagittal ( c ) images. Widespread enhancing urothelial wall thickening affects renal pelvis and the entire ureter ( a ). Multiple caliceal erosions with complete expulsion of necrotic papilla are recognizable in the upper and medium part of the kidney (full arrows), the inferior calyx presents a rose-thorn shape (empty arrows), while the lower pole is replaced by a large fluid cavity (*).

4.9. Fibroepithelial Polyp

A fibroepithelial polyp (FP) is a benign ureteral lesion, consisting of a fibrovascular stroma, covered by a layer of urothelium. It usually presents with hematuria or flank pain, and with a CTU aspect of a solid mass inside renal pelvis or ureter, so the differential diagnosis with a papillary UTUC is challenging ( Figure 17 ). The correct diagnosis could be supposed only in the presence of the typical appearance of a long pedunculated mass with smooth margins, entirely surrounded by contrast medium in the excretory phase, except for the attachment site of the stalk [ 12 , 28 , 29 ].

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g017.jpg

Fibroepithelial polyp: nephrographic-excretory axial ( a , b ) and CPR ( c ) images. A smooth-margin mass develops inside the ureter without associated wall thickening (arrows). Note complete lumen occlusion with upstream dilation and absent contrast excretion, by comparison with the contralateral normal ureter (empty arrow). When typical aspects are absent, differential diagnosis with UTUC is difficult.

4.10. Renal Cell Carcinoma

Renal Cell Carcinoma (RCC) typically appears as an expansive mass with well-defined margins and it is easily differentiated from urothelial carcinomas. Nevertheless, infiltrative RCCs could sometimes be difficult to distinguish from pyelocaliceal infiltrative UTUCs. Both malignancies show early contrast enhancement. However, the reniform shape is usually preserved in infiltrative tumors of the excretory tract, whereas a contour expansion can be seen in RCCs ( Figure 18 ) [ 14 , 16 , 34 ].

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g018.jpg

Recurrent RCC: cortico-medullary ( a ) and excretory ( b ) coronal images. A polilobulated lesion with inhomogeneous early contrast enhancement (full arrows) develops inside the renal parenchyma and extend in renal pelvis (*). The organ shape is altered and an exophytic mass is recognizable in the site of previous local surgery (empty arrows).

4.11. Renal Lymphoma

Extranodal spread of lymphoma often involves the urinary tract, but primary renal lymphoma without systemic disease is quite rare. Lymphomatous tissue could develop from renal capsule or perinephric and hilar fat, determining a vascular encasement and renal sinus involvement. It presents as a homogeneous soft-tissue lesion on non-enhanced CT with poor enhancement after contrast injection due to its hypovascularity, helping differential diagnosis with typical hypervascular RCCs and UTUCs. Lymphoma of the renal sinus could mimic the infiltrative pattern of UTUC, but lymphomatous tissue, due to its pliable nature, generally do not alter urinary tract shape nor causes hydronephrosis ( Figure 19 ) [ 16 , 35 , 36 ].

An external file that holds a picture, illustration, etc.
Object name is medicina-56-00705-g019.jpg

Renal sinus lymphoma: nephrographic-excretory axial ( a ) and MIP ( b ) images. Hypovascular and homogenous solid tissue diffusively involves renal sinus fat without distortion of pyelocaliceal system.

5. Conclusions

Computed tomography urography is a very useful tool in diagnostic workup of suspected upper urinary tract carcinoma. Some CTU features help to differentiate low-risk tumors from high-risk ones, leading to proper management. However, imaging findings could be nonspecific, and only the knowledge of possible UTUC mimickers guides a correct differential diagnosis, avoiding mistreatment.

Abbreviations

Author contributions.

Conceptualization, P.M.; writing—original draft preparation, A.M.B.; writing—review and editing, P.M. and M.F.M.C.; visualization, E.B.; supervision, M.A.C.; project administration, P.M. All authors have read and agreed to the published version of the manuscript.

This research received no external funding.

Conflicts of Interest

The authors declare no conflict of interest.

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Nonvisualized (“phantom”) renal calyx: Causes and radiological approach to diagnosis

  • Published: December 1980
  • Volume 1 , pages 17–23, ( 1980 )

Cite this article

  • Richard E. Brennan M.D. 1 &
  • Howard M. Pollack 2  

65 Accesses

16 Citations

Explore all metrics

A calyx which fails completely to opacify on excretory urography (phantom calyx) is often the harbinger of serious underlying renal disease. Causes of a phantom calyx include tuberculosis, tumor, calculus, ischemia, trauma, and congenital anomaly. The pathologic basis for the radiographic findings in each of these entities is described and an overall approach to diagnosis is set forth.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price includes VAT (Russian Federation)

Instant access to the full article PDF.

Rent this article via DeepDyve

Institutional subscriptions

Kollins SA, Hartman GW, Carr DT, Segura JW, Hattery RR: Roentgenographic findings in urinary tract tuberculosis: a ten year review. Am J Roentgenol 121 :487–499, 1974

CAS   Google Scholar  

Gay R: Focal exclusions in renal tuberculosis. Acta Radiol 32 :129–144, 1949

Article   CAS   PubMed   Google Scholar  

Barrie HJ, Kerr WK, Gale GL: The incidence and pathogenesis of tuberculous strictures of the renal pelvis. J Urol 98 :584–589, 1967

CAS   PubMed   Google Scholar  

Hartman GW, Segura JW, Hattery RR: Infectious diseases of the genitourinary tract. In DM Witten, GH Myers, DC Utz (eds): Emmett’s Clinical Urography: An Atlas and Textbook of Roentgenologic Diagnosis, Philadelphia: W.B. Saunders, 1977, pp 809–949

Google Scholar  

Silver TM, Kass EJ, Thornbury JR, Konnak JW, Wolfman MG: The radiological spectrum of acute pyelonephritis in adults and adolescents. Radiology 118 :65–71, 1976

Murchinson RJ, Nicholson TC: Absent collecting system sign. Urology 10 :343, 1977

Article   Google Scholar  

Levin DC, Gordon D, Kikhabwala M, Becker JA: Reticular neovascularity in malignant and inflammatory renal masses. Radiology 120 :61–68, 1976

Cope JR, Roylance J, Gordon IRS: The radiological features of Wilm’s tumour. Clin Radiol 23 ( 3 ):331–339, 1972

Heitzman ER, Perchik L: Radiographic features of renal infarction: review of 13 cases. Radiology 76 :39–46, 1961

Paul GJ, Stephenson TF: The cortical rim sign in renal infarction. Radiology 122 :338, 1977

Griscom NT, Kroeker MA: Visualization of individual papillary ducts (ducts by Bellini) by excretory urography in childhood hydronephrosis. Radiology 106 :385–389, 1973

Ambos MA, Bosniak MA: Tomography of the kidney bed as an aid in differentiating renal pelvic tumor and stone. Am J Roentgenol 125 :331–336, 1975

Pollack HM, Arger PH, Goldberg BB, Mulholland SG: Ultrasonic detection of nonopaque renal calculi. Radiology 127 :233–237, 1978

Webb JAW, Fry IK, Charlton CAC: An anomalous calyx in the mid-kidney: an anatomical variant. Br J Radiol 48 :674–677, 1975

Friedland GW, Filly RA: Appearing and disappearing calyces. Pediatr Radiol 1 ( 4 ):237–240, 1973

Dure’-Smith P: In RE Miller, J Skucas (eds): Radiographic Contrast Agents . Baltimore: University Park Press, 1977, p 297

Download references

Author information

Authors and affiliations.

Department of Radiology, Thomas Jefferson University Hospital, 11th and Walnut Streets, 19107, Philadelphia, PA, USA

Richard E. Brennan M.D.

Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA

Howard M. Pollack

You can also search for this author in PubMed   Google Scholar

Rights and permissions

Reprints and permissions

About this article

Brennan, R.E., Pollack, H.M. Nonvisualized (“phantom”) renal calyx: Causes and radiological approach to diagnosis. Urol Radiol 1 , 17–23 (1980). https://doi.org/10.1007/BF02926595

Download citation

Issue Date : December 1980

DOI : https://doi.org/10.1007/BF02926595

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

  • Calyx, disease of
  • Excretory urography
  • Find a journal
  • Publish with us
  • Track your research

Radiopaedia.org

  • Acute pyelonephritis
  • View revision history
  • Report problem with Article

Citation, DOI, disclosures and article data

At the time the article was created Frank Gaillard had no recorded disclosures.

At the time the article was last revised Rania Adel Anan had no financial relationships to ineligible companies to disclose.

  • Bacterial pyelonephritis
  • Acute pyelonephritides
  • Acute bacterial pyelonephritis

Acute pyelonephritis  (plural: acute pyelonephritides) is a bacterial infection of the renal pelvis and parenchyma most commonly seen in young women. It remains common and continues to have significant morbidity in certain groups of patients.

On this page:

Epidemiology, clinical presentation, radiographic features, treatment and prognosis, differential diagnosis, practical points, cases and figures, imaging differential diagnosis.

The incidence of acute pyelonephritis parallels that of lower urinary tract infections : approximately five times more common in females with a sharp increase following puberty 6 .

Clinical presentation is fairly specific and classical in most cases, consisting of a rapid onset of high fever, flank pain and costovertebral angle tenderness (i.e. positive Murphy's kidney punch). In many instances, less specific symptoms such as nausea, vomiting, dysuria, urinary frequency, urgency and other non-specific signs may also be present 1,12 .

White cells and bacteria are usually present in the urine, and blood tests reveal the expected changes: leukocytosis  and increased C-reactive protein (CRP) and/or erythrocyte sedimentation rate (ESR) . In severe cases, sepsis may be present.

The most commonly implicated organisms are from the gastrointestinal tract 5 :

Escherichia coli (most common)

Klebsiella spp.

Proteus spp.

Enterobacter spp.

Pseudomonas spp.

Haemophilus influenzae

Infection gains access to the upper urinary tract by passing retrograde up the ureter from the bladder, facilitated by virulence factors that allow bacteria to adhere to the urothelium (e.g. adhesin P) and inhibit ureteric peristalsis (endotoxins) 1,5 . The infection then passes into the collecting tubules and results in interstitial nephritis, with resulting alterations in renal filtration and blood flow in the affected region. Localized ischemia secondary to inflammatory changes results in altered imaging and may eventually lead to necrosis and scarring 2 .

In many instances, the clinical presentation suffices for making the diagnosis. Situations in which imaging is indicated include:

exclude obstructed kidney

high-risk patients: diabetics, elderly, immunocompromised

those with a mixed clinical picture

previous renal pathology

Plain radiograph

Radiography has a limited role, especially if patients are likely to go on to CT. Abdominal radiographs may demonstrate obstructing urinary tract calculi and occasionally may demonstrate gas within the collecting system ( emphysematous pyelonephritis ).

Ultrasound is insensitive to the changes of acute pyelonephritis, with most patients having 'normal' scans. Abnormalities are identified in only ~25% of cases 1 . Possible features include:

particulate matter/debris in the collecting system

reduced areas of cortical vascularity by using power Doppler 

gas bubbles ( emphysematous pyelonephritis )

abnormal echogenicity of the renal parenchyma 1

focal/segmental hypoechoic regions (in edema) or hyperechoic regions (in hemorrhage)

mass-like change

Ultrasound is, however, useful in assessing for local complications such as hydronephrosis , renal abscess formation, renal infarction , perinephric collections , and thus may guide management.

CT is a sensitive modality for evaluation of the renal tract, able to assess for renal calculi , gas, perfusion defects, collections and obstruction. Unfortunately, it does have a significant radiation burden and should be used sparingly, especially in young patients.

There is usually no need for a three or four phase CT IVP (CT urography). A single 45-90 second post-contrast scan usually suffices, although clinical acumen may be necessary to choose the best contrast phase 1,3 . For example, if renal colic is suspected then a non-contrast scan is often required to assess for renal calculi. If renal ischemia is suspected then an arterial scan (15-25 seconds) is ideal to assess perfusion 3 .

Non-contrast CT

often the kidneys appear normal

affected parts of the kidney may appear edematous, i.e. swollen and of lower attenuation

renal calculi or gas within the collecting system may be evident

perinephric stranding : although not considered a useful sign 7

Post-contrast CT

one or more focal wedge-like regions will appear swollen and demonstrate reduced enhancement compared with the normal portions of the kidney

the periphery of the cortex is also affected, helpful in distinguishing acute pyelonephritis from a renal infarct (which tends to spare the periphery; the so-called ' rim sign ')

if imaged during the excretory phase, a striated nephrogram may also be visible 3,4

If for some reason the kidney is imaged again within 3-6 hours, persistent enhancement of the affected regions may be evident due to slow flow of contrast through the involved tubules 1,3 .

MRI is usually reserved for patients who are pregnant, and findings mirror those seen on CT. The kidney demonstrates wedge-shaped regions of altered signal:

T1:  affected region(s) appear hypointense compared with the normal kidney parenchyma

T2:  hyperintense compared to normal kidney parenchyma

T1 C+:  reduced enhancement

A fast inversion recovery sequence obtained after contrast administration has been shown to be particularly effective in outlining affected regions which appear hyperintense compared to the low signal parenchyma. The contrast is thought to represent a combination of local edema and decreased T2 signal due to gadolinium in the perfused 'normal' portions 2 .

Nuclear medicine

Technetium-99m dimercaptosuccinic acid (DMSA) demonstrates a similar reduction in renal perfusion and function, which appears as one or more patchy scintigraphy defects in the outline of the kidneys 2 .

Patients should be treated with antibiotics, analgesia and antipyretics 10 . Empirical antibiotics should be commenced initially and adjusted accordingly to urine culture results. Most patients respond rapidly to appropriate oral antibiotic therapy, and often no imaging whatsoever is required. IV antibiotics are reserved for complicated cases of acute pyelonephritis.

Even when imaging has been performed, no follow-up imaging is usually required, unless patients do not respond clinically, and it should be stressed that imaging changes can take up to five months to resolve 1 .

The presence of an upper urinary tract infection in the presence of obstruction can threaten the viability of the kidney and a percutaneous nephrostomy is usually required on an emergency basis.

Complications

Complications include 2 :

lobar nephronia

renal abscess

perinephric abscess

renal papillary necrosis

emphysematous pyelonephritis

renal infarction , necrosis and scarring

chronic renal impairment

hypertension

renal vein thrombosis 10

in pregnancy: septic shock and premature labor 11

General imaging differential considerations include:

renal infarction

typically spares the peripheral aspect of the cortex, giving the cortical rim sign

other causes of interstitial nephritis

sarcoidosis

drug-induced

renal lymphoma : has multiple presentations and can mimic pyelonephritis

CT is the most sensitive modality for diagnosis and assessment of complications

CT portal venous phase demonstrating areas of reduced enhancement compared with the normal portions of the kidney is the key for diagnosis

striated nephrogram  on CT excretory phase

evidence of obstruction in the setting of pyelonephritis/sepsis is a medical urgency requiring percutaneous nephrostomy

Quiz questions

  • 1. Craig WD, Wagner BJ, Travis MD. Pyelonephritis: radiologic-pathologic review. (2008) Radiographics : a review publication of the Radiological Society of North America, Inc. 28 (1): 255-77; quiz 327-8. doi:10.1148/rg.281075171 - Pubmed
  • 2. Majd M, Nussbaum Blask AR, Markle BM et-al. Acute pyelonephritis: comparison of diagnosis with 99mTc-DMSA, SPECT, spiral CT, MR imaging, and power Doppler US in an experimental pig model. Radiology. 2001;218 (1): 101-8. Radiology (full text) - Pubmed citation
  • 3. Johnson PT, Horton KM, Fishman EK. Optimizing detectability of renal pathology with MDCT: protocols, pearls, and pitfalls. AJR Am J Roentgenol. 2010;194 (4): 1001-12. doi:10.2214/AJR.09.3049 - Pubmed citation
  • 4. Zagoria RJ. Genitourinary radiology, the requisites. Mosby Inc. (2004) ISBN:0323018424. Read it at Google Books - Find it at Amazon
  • 5. Jennette JC, Heptinstall RH. Heptinstall's pathology of the kidney. Lippincott Williams & Wilkins. (2007) ISBN:0781747503. Read it at Google Books - Find it at Amazon
  • 6. Foxman B, Klemstine KL, Brown PD. Acute pyelonephritis in US hospitals in 1997: hospitalization and in-hospital mortality. Ann Epidemiol. 2003;13 (2): 144-50. Ann Epidemiol (link) - Pubmed citation
  • 7. Fukami H, Takeuchi Y, Kagaya S, Ojima Y, Saito A, Sato H, Matsuda K, Nagasawa T. Perirenal fat stranding is not a powerful diagnostic tool for acute pyelonephritis. (2017) International journal of general medicine. 10: 137-144. doi:10.2147/IJGM.S133685 - Pubmed
  • 8. Chen WL, Huang IF, Wang JL, Hung CH, Huang JS, Chen YS, Lee SS, Hsieh KS, Tang CW, Chien JH, Chiou YH, Cheng MF. Comparison of acute lobar nephronia and acute pyelonephritis in children: a single-center clinical analysis in southern taiwan. (2015) Pediatrics and neonatology. 56 (3): 176-82. doi:10.1016/j.pedneo.2014.08.002 - Pubmed
  • 9. Conley SP, Frumkin K. Acute lobar nephronia: a case report and literature review. (2014) The Journal of emergency medicine. 46 (5): 624-6. doi:10.1016/j.jemermed.2013.08.097 - Pubmed
  • 10. Belyayeva M, Jeong JM. Acute Pyelonephritis. 2022 Sep 18. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan–. PMID: 30137822.
  • 11. Wolfgang Dähnert. Radiology Review Manual. (2011) ISBN: 9781609139438
  • 12. Belyayeva M, Belyayeva JJ, Belyayeva. Acute Pyelonephritis. (2021) . doi: - Pubmed

Incoming Links

  • Periportal halo (CT/US)
  • Unilateral renal enlargement (differential)
  • Renal antibioma
  • Bilateral renal enlargement
  • Renal lymphoma
  • Perinephric stranding
  • Lobar nephronia
  • Cortical rim sign (kidneys)
  • Diffuse gallbladder wall thickening (differential)
  • Bladder exstrophy
  • RANZCR key conditions assessment
  • Nephrotic syndrome
  • Perinephric abscess
  • Striated nephrogram
  • Pyelonephritis
  • Phantom calyx
  • Urogenital curriculum
  • Dromedary hump
  • Renal papillary necrosis
  • Emphysematous pyelitis and pyelonephritis
  • Colovesical fistula
  • Severe pyelonephritis with abscesses
  • Acute and chronic pyelonephritis with renal abscess
  • Acute pyelonephritis with renal and perinephric abscesses
  • Infectious colitis
  • Acute pyelonephritis (dual energy CT)
  • Acute pyelonephritis - striated nephrogram
  • Pyelonephritis in pregnancy (MRI)
  • Chromophobe renal cell carcinoma
  • Emphysematous Pyelonephritis
  • Acute bilateral pyelonephritis
  • Acute pyelonephritis with renal vein thrombosis
  • Question 2094
  • Question 2091
  • Question 420
  • Question 419
  • Question 378

Promoted articles (advertising)

ADVERTISEMENT: Supporters see fewer/no ads

phantom calyx radiology

Loading more images...

Please Note: You can also scroll through stacks with your mouse wheel or the keyboard arrow keys

Loading Stack -

0 images remaining

By Section:

  • Artificial Intelligence
  • Classifications
  • Imaging Technology
  • Interventional Radiology
  • Radiography
  • Central Nervous System
  • Gastrointestinal
  • Gynaecology
  • Haematology
  • Head & Neck
  • Hepatobiliary
  • Interventional
  • Musculoskeletal
  • Paediatrics
  • Not Applicable

Radiopaedia.org

  • Feature Sponsor
  • Expert advisers

phantom calyx radiology

Nonvisualized ("phantom") renal calyx: causes and radiological approach to diagnosis

  • PMID: 399818
  • DOI: 10.1007/BF02926595

A calyx which fails completely to opacify on excretory urography (phantom calyx) is often the harbinger of serious underlying renal disease. Causes of a phantom calyx include tuberculosis, tumor, calculus, ischemia, trauma, and congenital anomaly. The pathologic basis for the radiographic findings in each of these entities is described and an overall approach to diagnosis is set forth.

Publication types

  • Diagnosis, Differential
  • Ischemia / diagnostic imaging
  • Kidney / blood supply
  • Kidney / injuries
  • Kidney Calculi / diagnostic imaging
  • Kidney Calices / diagnostic imaging*
  • Kidney Neoplasms / diagnostic imaging
  • Kidney Pelvis / diagnostic imaging*
  • Pyelonephritis / diagnostic imaging
  • Radiography
  • Renal Artery Obstruction / diagnostic imaging
  • Tuberculosis, Renal / diagnostic imaging

Europe PMC requires Javascript to function effectively.

Either your web browser doesn't support Javascript or it is currently turned off. In the latter case, please turn on Javascript support in your web browser and reload this page.

Search life-sciences literature ( 43,479,811 articles, preprints and more)

  • Available from publisher site using DOI. A subscription may be required. Full text
  • Citations & impact
  • Similar Articles

Nonvisualized ("phantom") renal calyx: causes and radiological approach to diagnosis.

Urologic Radiology , 01 Jan 1979 , 1(1): 17-23 https://doi.org/10.1007/bf02926595   PMID: 399818 

Abstract 

Full text links .

Read article at publisher's site: https://doi.org/10.1007/bf02926595

References 

Articles referenced by this article (16)

Roentgenographic findings in urinary tract tuberculosis. A 10 year review.

Kollins SA , Hartman GW , Carr DT , Segura JW , Hattery RR

Am J Roentgenol Radium Ther Nucl Med, (3):487-499 1974

MED: 4846564

Focal exclusions in renal tuberculosis.

Acta radiol, (2-3):129-44, illust 1949

MED: 15392640

The incidence and pathogenesis of tuberculous strictures of the renal pyelus.

Barrie HJ , Kerr WK , Gale GL

J Urol, (5):584-589 1967

MED: 6065513

Hartman GW, Segura JW, Hattery RR: Infectious diseases of the genitourinary tract. In DM Witten, GH Myers, DC Utz (eds): Emmett’s Clinical Urography: An Atlas and Textbook of Roentgenologic Diagnosis, Philadelphia: W.B. Saunders, 1977, pp 809–949

The radiological spectrum of acute pyelonephritis in adults and adolescents..

Silver TM , Kass EJ , Thornbury JR , Konnak JW , Wolfman MG

Radiology, (1):65-71 1976

MED: 1244676

Case profile: absent collecting system sign.

Murchison RJ , Nicholson TC

Urology, (4):343 1977

MED: 919119

Reticular neovascularity in malignant and inflammatory renal masses.

Levin DC , Gordon D , Kinkhabwala M , Becker JA

Radiology, (1):61-68 1976

MED: 935466

The radiological features of Wilms' tumour.

Cope JR , Roylance J , Gordon IR

Clin Radiol, (3):331-339 1972

MED: 4339980

Radiographic features of renal infarction; review of 13 cases.

HEITZMAN ER , PERCHIK L

Radiology, 39-46 1961

MED: 13713041

The cortical rim sign in renal infarction.

Paul GJ , Stephenson TF

Radiology, (2):338 1977

MED: 834872

Citations & impact 

Impact metrics, citations of article over time, article citations, tuberculosis of the genitourinary system-urinary tract tuberculosis: renal tuberculosis-part ii..

Merchant S , Bharati A , Merchant N

Indian J Radiol Imaging , 23(1):64-77, 01 Jan 2013

Cited by: 21 articles | PMID: 23986619 | PMCID: PMC3737619

Endoscopic management of completely excluded calices: a single institution experience.

Mues AC , Landman J , Gupta M

J Endourol , 24(8):1241-1245, 01 Aug 2010

Cited by: 4 articles | PMID: 20590422

Imaging of hematuria.

O'Connor OJ , McSweeney SE , Maher MM

Radiol Clin North Am , 46(1):113-32, vii, 01 Jan 2008

Cited by: 19 articles | PMID: 18328883

The role of imaging in the investigation of painless hematuria in adults.

O'Regan KN , O'Connor OJ , McLoughlin P , Maher MM

Semin Ultrasound CT MR , 30(4):258-270, 01 Aug 2009

Cited by: 4 articles | PMID: 19711639

Percutaneous nephrolithotomy of patients with staghorn stone and incidental purulent fluid suggestive of infection.

Hosseini MM , Basiri A , Moghaddam SM

J Endourol , 21(12):1429-1432, 01 Dec 2007

Cited by: 12 articles | PMID: 18186679

Similar Articles 

To arrive at the top five similar articles we use a word-weighted algorithm to compare words from the Title and Abstract of each citation.

[Differential diagnosis of contrast medium recesses of the renal pelvis or the renal calyx system (author's transl)].

Zwicker H , Bonvin B , Alder W

Rontgenblatter , 32(4):157-163, 01 Apr 1979

Cited by: 0 articles | PMID: 441642

[The syndrome of the upper calyx in children with chronic pyelonephritis (author's transl)].

Benz G , Willich E

Fortschr Geb Rontgenstr Nuklearmed , 121(4):445-454, 01 Oct 1974

Cited by: 0 articles | PMID: 4373341

[Radiographic evaluation of upper calyx syndrome].

Winnicki S , Florczak-Mikicińska E , Pruszyńska-Podemska W

Probl Med Wieku Rozwoj , 13:68-72, 01 Jan 1984

Cited by: 0 articles | PMID: 6531354

Computed tomography of the kidney.

Dunnick NR , Korobkin M

Radiol Clin North Am , 22(2):297-313, 01 Jun 1984

Cited by: 2 articles | PMID: 6379733

[A case report of milk of calcium in a renal calyceal diverticulum].

Matsuzaki S

Hinyokika Kiyo , 34(4):661-664, 01 Apr 1988

Cited by: 0 articles | PMID: 3041776

Europe PMC is part of the ELIXIR infrastructure

  • Radiology Key

Fastest Radiology Insight Engine

  • BREAST IMAGING
  • CARDIOVASCULAR IMAGING
  • COMPUTERIZED TOMOGRAPHY
  • EMERGENCY RADIOLOGY
  • FETAL MEDICINE
  • FRCR READING LIST
  • GASTROINTESTINAL IMAGING
  • GENERAL RADIOLOGY
  • GENITOURINARY IMAGING
  • HEAD & NECK IMAGING
  • INTERVENTIONAL RADIOLOGY
  • MAGNETIC RESONANCE IMAGING
  • MUSCULOSKELETAL IMAGING
  • NEUROLOGICAL IMAGING
  • NUCLEAR MEDICINE
  • OBSTETRICS & GYNAECOLOGY IMAGING
  • PEDIATRIC IMAGING
  • RADIOGRAPHIC ANATOMY
  • RESPIRATORY IMAGING
  • ULTRASONOGRAPHY
  • Abdominal Key
  • Anesthesia Key
  • Basicmedical Key
  • Otolaryngology & Ophthalmology
  • Musculoskeletal Key
  • Obstetric, Gynecology and Pediatric
  • Oncology & Hematology
  • Plastic Surgery & Dermatology
  • Clinical Dentistry
  • Thoracic Key
  • Veterinary Medicine
  • Gold Member
  • iOS/Android App

Renal Infections and Renal Fungal Infections

Fig. 1 Chronic pyelonephritis. ( a ) Typical calyceal deformations. ( b , c ) Intravenous excretory urography. Progressive calyceal distortion ( arrows ) due to the underlying renal parenchymal damage and scarring Fig. 2 Chronic pyelonephritis. Multidetector CT urography. Coronal reformations. ( a , b ) Right kidney. Calyceal distortion and clubbing ( arrows ) due to the underlying renal parenchymal damage with renal parenchymal scarring and focal reduction of renal parenchymal thickness. ( c , d ) Left kidney. Diffuse reduction of the renal parenchymal thickness with calyceal distortion ( arrows ) The goals of imaging in chronic recurrent pyelonephritis are the detection of chronic renal damage and the detection of abnormalities that are often the cause of recurrence. However it should be stressed that there are no radiological features that at a single point in time reliably indicate activity of the process. Therefore, the goals of radiological investigations become the detection of abnormalities that are often the cause of the recurrence (i.e., infectious stones) and the detection of the chronic renal damage. In the past, intravenous excretory urography and nephrotomography and, nowadays, CT urography are often capable to achieve these two goals. Findings related to the chronic renal damage (decrease of the kidney size, parenchymal scars, calyceal distortion; Fig. 1 ) are easily depicted at intravenous excretory urography. Multidetector computed tomography (CT) urography and magnetic resonance (MR) imaging readily identify the chronic renal parenchymal damage and calyceal distortion and clubbing (Fig. 2 ). 2 Renal Tuberculosis Genitourinary tuberculosis is the most common manifestation of extrapulmonary tuberculosis (Engin et al. 2000 ; Harisinghani et al. 2000 ) accounting for 15–20 % of infections outside the lungs (Gibson et al. 2004 ). Approximately 4–8 % of patients with pulmonary tuberculosis will develop clinically significant genitourinary infection (Gibson et al. 2004 ). Mycobacterium tuberculosis reaches the genitourinary organs, particularly the kidneys, by the hematogenous seeding from disease in the lungs. The seeding occurs at the time of the initial lung infection with seeding of Mycobacterium tuberculosis in the periglomerular and peritubular capillary bed. Small granulomas form in the renal cortex bilaterally, adjacent to the glomeruli, and remain stable for many years (Kenney 1990 ). A high rate of perfusion and favorable oxygen tension increase the likelihood of bacilli proliferating in this location (Gibson et al. 2004 ). In patients with intact cellular immunity, the disease remains confined to the renal cortex, while in some patients, breakdown of host defense mechanisms leads to reactivation of the cortical granulomas with enlargement and coalescence and organisms spread into the real medulla causing a papillitis which may extend into the collecting system (Kenney 1990 ). In fact, after capillary rupture the organisms migrate to the proximal tubule and loop of Henle with eventual development of enlarging, caseating granulomas and papillary necrosis. Granuloma formation, caseous necrosis, and cavitation are stages of progressive infection, which can eventually determine the loss of renal function and calcification of the entire kidney (autonephrectomy). The renal disease remains quiescent until there is an insult to the host’s immunity at which time reactivation occurs. Patients with genitourinary tuberculosis typically have local symptoms including frequent voiding and dysuria. Hematuria can be either microscopic or macroscopic. Symptoms may also include back, flank, or abdominal pain (Simon et al. 1977 ; Gibson et al. 2004 ). Constitutional symptoms such as fever, weight loss, fatigue, and anorexia are less common (Simon et al. 1977 ; Gibson et al. 2004 ). Laboratory abnormalities include pyuria, proteinuria, and hematuria. Standard urine cultures can be normal. Furthermore, the presence of routine urinary tract pathogens can delay the diagnosis of coexistent tuberculosis (Gibson et al. 2004 ). Mycobacterium tuberculosis is isolated from the urine in 80–95 % of patients with genitourinary tuberculosis. In adults renal tuberculosis is the most known etiology of infundibular strictures with consequent hydrocalyx. Obstruction may develop early or during the healing phase, even while the patient is receiving antitubercular therapy. It must be underlined that each finding of renal tuberculosis can be caused by other diseases, but multiple abnormalities are usually present and allow a correct diagnosis. That’s why renal tuberculosis is called the “great imitator.” On the plain film and unenhanced CT, the kidney may appear large, normal sized, or small. Despite hematogenous seeding of both kidneys, clinically significant disease is usually limited to one side and approximately 75 % of renal tuberculous involvement is unilateral. The grayscale US appearance of renal tuberculosis is not specific. US is advisable to evaluate the nonfunctioning kidney after iodinated contrast agent injection and for the follow-up of antitubercular therapy. The kidney may appear large, normal sized, or small, and calcifications are common. Hydronephrosis or hypoechoic parenchymal lesions, which correspond to parenchymal abscesses resulting from caseating necrosis, may be observed. CT urography, as in the past intravenous excretory urography, is now considered the correct imaging technique to assess the upper urinary tract, including the involvement in renal tuberculosis. The most common CT finding is renal calcifications (37–71 %) (Gibson et al. 2004 ) which follow different patterns. Calcifications may be amorphous, granular, lobar, or curvilinear and frequently extend beyond the kidney (e.g., psoas muscle). CT urography allows a more accurate evaluation of the amount of residual functioning parenchyma and of the extrarenal spread (Kenney 1990 ). Nowadays CT urography represents the most accurate imaging technique to reveal early manifestations of renal tuberculosis (Fig. 3 ). The earliest morphologic alterations of renal parenchyma corresponding to calyceal alterations determined by tuberculosis include calyceal erosion (“moth-eaten calyx”) (Fig. 4a ) with progression toward medullary (Fig. 4b ) or papillary necrosis (Fig. 4c, d ). The pathological features of renal tuberculosis are extremely different, and frequently different features coexist (Fig. 4b ). Common sites of tuberculous strictures are the calyceal neck with hydrocalyx (Figs. 5a and 6 ) or phantom calyx (Figs. 5b–d and 7 ); the infundibulum of a calyx with hydrocalyx or regional or focal hydrocalycosis (Fig. 8 ); the ureteropelvic junction with dilatation of the entire renal pelvis, calyces, and infundibula (Fig. 9 ); and the lower ureteral segment. Tubercular strictures often coexist with adjacent renal parenchymal scarring. The development of infundibular, pelvic, or ureteral strictures is nearly pathognomonic of renal tuberculosis (Kenney 1990 ). An infundibular stricture may result in a “phantom calyx” when that segment of the kidney becomes nonfunctional (Fig. 5b–d ) (Kenney 1990 ). CT is very accurate in demonstrating parenchymal gross calcifications (Fig. 8 ). Fig. 3 The early morphologic alterations of renal parenchyma determined by tuberculosis. The fundamental calyceal alterations in renal tuberculosis: calyceal erosion ( a ), medullary necrosis ( b ), papillary necrosis ( c ), and infundibular stricture without ( d ) or with hydrocalyx ( e ) Fig. 4 Renal tuberculosis. ( a ) Intravenous excretory urography. Calyceal distortion due to initial erosion ( small arrows ). ( b ) Intravenous excretory urography. Renal medullary necrosis ( arrow ) with evidence also of infundibular stricture ( arrowhead ) and adjacent hydrocalyx. ( c ) Intravenous excretory urography. Papillary necrosis ( arrows ). ( d ) CT urography. Maximum intensity projection. Renal medullary necrosis ( arrow ) in one of the renal calyces of the lower group Fig. 5 Renal tuberculosis. ( a ) Intravenous excretory urography. Tubercular stricture ( small arrow ) with evidence of hydrocalyx ( large arrow ) and adjacent calyceal erosion ( long arrow ). ( b ) Intravenous excretory urography and ( c , d ) nephrotomography. Tubercular infundibular stricture ( arrows ) with phantom calyx. ( d ) Renal infundibular stricture ( arrowheads ) often coexists with adjacent renal parenchymal scar Fig. 6 Renal tuberculosis. ( a , b ) CT urography. Transverse scan. ( a ) Infundibular stricture ( arrow ) due to fibrosclerosing tuberculosis with narrowing of the infundibulum. ( b ) Dilatation of an upper renal calyx (hydrocalyx) Fig. 7 Renal tuberculosis. CT urography. Transverse scan. Infundibular stricture ( arrow ) due to fibrosclerosing tuberculosis with narrowing of the infundibulum and phantom calyx Fig. 8 Renal tuberculosis. ( a , b ) Ultrasound scan, longitudinal view. Segmental dilatation of the upper urinary tract ( arrow ) with focal calcification within the renal parenchyma (calipers) and retraction of the renal profile. Unenhanced ( c , d ) and contrast-enhanced CT ( e , f ) show the renal parenchymal calcifications ( arrow ) with segmental dilatation of the intrarenal urinary tract. ( g ) CT urography, maximum intensity projection. Segmental dilatation of the upper urinary tract with hydrocalyx ( arrow ) due to fibrosclerosing tuberculosis with tuberculous stricture at the superior infundibulum with regional hydrocalycosis ( arrow ) Fig. 9 A 63-year-old patient with renal tuberculosis. Contrast-enhanced nephrographic phase CT. US ( a ) transverse scan; ( b ) longitudinal scan. Dilatation of the renal pelvis ( arrow ), which is confirmed by contrast-enhanced CT ( c , d ). Renal tuberculosis determines a fibrosclerosis of the ureteropelvic junction with consequent markedly dilated calyces and renal parenchymal thinning Renal tuberculosis may manifest as extensive cavitation (open or extensive forms) or fibrosclerosis (closed forms) (Becker 1988 ; Wang et al. 1997 ). The open or extensive form (Fig. 10 ) corresponds to noncommunicating parenchymal cavities or to communicating cavities with extension of the caseified tissue necrosis to the intrarenal excretory tract (Fig. 11 ). Parenchymal masses can develop which may be calcified (Kenney 1990 ). Communication of the granulomas with the collecting system (Fig. 12 ) can lead to regional spread of the bacilli into the renal pelvis, ureters, urinary bladder, and accessory genital organs. Extensive cavitation may determine renal caseation, whereas fibrosing reaction of the urinary tract results in obstructive hydronephrosis. When the process spreads into the collecting system, the disease can evolve in three ways: (1) extensive cavitation (Figs. 13 and 14 ), (2) fibrosclerosis with resulting noncommunicating cavities (Figs. 14 , 15 , 16 and 17 ), and (3) recurrent “poussées.” Fig. 10 Renal tuberculosis with caseified tissue necrosis. Open forms. The extensive cavitation of renal parenchyma results in noncommunicating ( a ) or communicating cavities ( b ) with the intrarenal excretory tract with deformation of the adjacent renal calyces from the simple narrowing of the calyx, medullary, and papillary necrosis, up to obstructive hydronephrosis Fig. 11 Evolution of the open forms of renal tuberculosis. The caseified tissue necrosis ( a ) progressively spreads to the renal urinary tract ( b ). The progressive fibrosclerosis results in a noncommunicating cavity ( c ) Fig. 12 Open or extensive form. Intravenous excretory urography–nephrotomography with cavitation ( arrow ) and extension of the caseified tissue necrosis to the intrarenal excretory tract Fig. 13 ( a ) CT urography, coronal reformation. ( b ) Maximum intensity projection. A parenchymal cavity ( arrow ) communicating with the renal excretory tract is visualized on the right kidney Fig. 14 Diffuse cavitating open form of renal tuberculosis. ( a ) Intravenous urography, and ( b ) grayscale ultrasound. Evidence of multiple cavities ( arrow ) on the upper pole of the left kidney communicating with the intrarenal collecting system. ( c – f ) Contrast-enhanced CT during the excretory phase. The left kidney shows diffuse parenchymal cavitation with resulting communicating ( arrows in c and d ) and noncommunicating cavities ( arrow and caliper in e and f ) Fig. 15 ( a , b ) Renal tuberculosis. CT urography. Coronal ( a ) and sagittal ( b ) reformations of the right kidney. Fibrosclerosing tuberculosis with gross calcification ( arrow ) at the level of the renal parenchyma and adjacent noncommunicating cavity Fig. 16 ( a – d) Open form of renal tuberculosis with diffusion into the intrarenal collecting system extensive cavitation and fibrosclerosis with resulting noncommunicating cavities. Contrast-enhanced CT during the excretory phase. Extension of the caseified tissue necrosis to the intrarenal excretory tract with parenchymal fibrosclerosis with calcifications and irregularities of the renal margins ( arrow ) and resulting noncommunicating cavities Fig. 17 Open form with diffusion into the intrarenal collecting system extensive cavitation and fibrosclerosis with resulting noncommunicating cavities. ( a ) Intravenous excretory urography. Irregularities in the morphology and deformations of the renal calyces ( arrows ). ( b – d ) Contrast-enhanced CT during the excretory phase. Renal parenchymal extensive necrosis with noncommunicating cavities ( arrows ) in both kidneys and parenchymal fibrosclerosis with calcifications and irregularities of the renal margins The closed or fibrosclerotic form (Fig. 18 ) presents a better outcome to therapy and consists in the extension of the caseified necrosis toward the renal parenchyma. The host’s healing response induces fibrosis with calcium deposition, focal fibrosis with progressive parenchymal scarring, stricture formation with dilatation of the intrarenal urinary tract, and autonephrectomy (no functional contrast excretion). The fibrosclerotic forms of renal TB may appear as (1) pure fibrosclerosis with parenchymal scar (Fig. 19 ) often with evidence of noncommunicating cavities (Fig. 20 ) and (2) reactivation of the granulomatous process over a permanent status of fibrosclerosis with caseous necrosis and cavitation, or mixed fibrosclerotic and cavitating form, and resulting communicating or noncommunicating cavities with the intrarenal urinary tract (Fig. 21 ). Both forms determine parenchymal calcifications, deformation of the adjacent renal calyces from the simple narrowing of the calyx to medullary and papillary necrosis to obstructive hydronephrosis or hydrocalyx. Fig. 18 ( a ) Scheme. Closed form of renal tuberculosis. The pathological process extends toward the renal parenchyma with progressive fibrosclerosis ( arrow ) and distortion of the adjacent renal calyces. ( b ) CT urography. Typical parenchymal fibrosclerosis ( large arrow ) with adjacent gross parenchymal calcification ( small arrow ) Fig. 19 ( a , b ) Closed form of renal tuberculosis. Contrast-enhanced CT during the excretory phase. The right kidney shows extensive parenchymal fibrosclerosis ( large arrows ) with scar, dilatation of the intrarenal excretory tract ( small arrows ), and loss of excretory function with autonephrectomy (no contrast excretion is evident)

Share this:

  • Click to share on Twitter (Opens in new window)
  • Click to share on Facebook (Opens in new window)

Related posts:

phantom calyx radiology

Comments are closed for this page.

phantom calyx radiology

Full access? Get Clinical Tree

phantom calyx radiology

Palouse Imaging Consultants

Your Medical Imaging Experts on the Palouse

Located in Moscow, Idaho, Palouse Imaging Consultants has provided pioneering medical imaging and interpretation services to the area for more than 50 years. We pair state-of-the-art technology and personalized consultation with physicians, providers, technologists, and patients to provide the absolute best care.

phantom calyx radiology

Pay My Bill

Thank you for entrusting Palouse Imaging Consultants to be an integral part of your health care team. For your convenience, you may securely pay your bill through the link below. 

What Makes Us Different

Alongside our dedication to continuously improving the services we provide, we pride ourselves on the human touch we bring to our Radiology practice. We are personable, approachable, knowledgeable, and honored to be a trusted part of your healthcare team. Give us a call and a friendly voice will be happy to help with any questions or concerns.

IMAGES

  1. Male Genito-Urinary Tuberculosis

    phantom calyx radiology

  2. Phantom

    phantom calyx radiology

  3. Renal Calcifications with Dilated Calyxes Lower Pole Left Kidney and

    phantom calyx radiology

  4. Classic Signs in Uroradiology

    phantom calyx radiology

  5. Pelvis Phantom

    phantom calyx radiology

  6. Male Genito-Urinary Tuberculosis

    phantom calyx radiology

VIDEO

  1. Calyx and Teebee

  2. Aster Calyx

  3. Reading an X-ray

  4. Calyx Köşe Koltuk Takımı

  5. Calyx

  6. Calyx & TeeBee

COMMENTS

  1. Phantom calyx

    A phantom calyx is a solitary calyx which fails to opacify with contrast amidst an otherwise well-opacified pelvicalyceal system. It is due to an intrarenal process which has infiltrated and caused obliteration of the involved collecting system element. It may be seen in: tumor: especially transitional cell carcinoma of the renal pelvis

  2. Renal tuberculosis

    Citation, DOI, disclosures and article data. Renal tuberculosis, a subset of genitourinary tuberculosis, accounts for 15-20% of extra-pulmonary tuberculosis and can result in varied and striking radiographic appearances. Tuberculosis can involve both the renal parenchyma and the collecting system (calyces, renal pelvis, ureter, bladder and ...

  3. CT Urography Findings of Upper Urinary Tract Carcinoma and Its

    Urothelial carcinoma (UC) is the fourth most frequent tumor in Western countries and upper tract urothelial carcinoma (UTUC), affecting pyelocaliceal cavities and ureter, accounts for 5-10% of all UCs. Computed tomography urography (CTU) is now considered the imaging modality of choice for diagnosis and staging of UTUC, guiding disease management.

  4. Classic Signs in Uroradiology

    The language of radiology is rich with descriptions of imaging findings, often metaphorical, which have found common usage in the day-to-day practice of genitourinary radiology. These "classic signs" give us confidence in our diagnosis. Some of the signs have become so familiar to us that they are referred to as an "Aunt Minnie."

  5. The "phantom" calyx

    A "phantom" calyx refers to the imaging finding of lack of contrast opacification of a calyx or portion of the collecting system, where one should be, within an otherwise well-opacified pelvicalyceal system [ 1 ]. This appearance most often reflects a process that has infiltrated or obliterated the collecting system element [ 1 ].

  6. Imaging of Hematuria

    OBJECTIVE. In this article, we will discuss the current status of imaging in patients with hematuria of urologic origin. Issues impacting evaluation of these patients with radiography, excretory urography, retrograde pyelography, and sonography will be discussed. CONCLUSION.

  7. Nonvisualized ("phantom") renal calyx: Causes and ...

    A calyx which fails completely to opacify on excretory urography (phantom calyx) is often the harbinger of serious underlying renal disease. Causes of a phantom calyx include tuberculosis, tumor, calculus, ischemia, trauma, and congenital anomaly.

  8. PDF Nonvisualized ( Phantom) Renal Calyx: Causes and ...

    A alyx fails which completely to opacify the lumina of the collecting tubules leads to the on excretory urography (phantom calyx) is often the mation of medullary cavities, and granulomatous in- harbinger of serious underlying renal disease. Causes filtration of the urothelium.

  9. The "phantom" calyx

    Causes of a phantom calyx include tuberculosis, tumor, calculus, ischemia, trauma, and congenital anomaly. ... which have found common usage in the day-to-day practice of genitourinary radiology ...

  10. Nonvisualized ("phantom") renal calyx: Causes and radiological approach

    The pathologic basis for the radiographic findings in each of the causes of a phantom calyx include tuberculosis, tumor, calculus, ischemia, trauma, and congenital anomaly. A calyx which fails completely to opacify on excretory urography (phantom calyx) is often the harbinger of serious underlying renal disease. Causes of a phantom calyx include tuberculosis, tumor, calculus, ischemia, trauma ...

  11. Acute pyelonephritis

    Citation, DOI, disclosures and article data. Acute pyelonephritis (plural: acute pyelonephritides) is a bacterial infection of the renal pelvis and parenchyma most commonly seen in young women. It remains common and continues to have significant morbidity in certain groups of patients.

  12. Nonvisualized ("phantom") renal calyx: causes and radiological ...

    A calyx which fails completely to opacify on excretory urography (phantom calyx) is often the harbinger of serious underlying renal disease. Causes of a phantom calyx include tuberculosis, tumor, calculus, ischemia, trauma, and congenital anomaly. The pathologic basis for the radiographic findings i …

  13. Neoplasms of the Renal Pelvis and Ureter

    Phantom calyx - Unopacified calyx secondary to obstruction of infundibulum. Causes of a phantom calyx include tuberculosis, tumor, calculus, ischemia, trauma, and congenital anomaly. Ureteral tumors are observed as ureteral filling defect with variable proximal ureteral dilatation.

  14. Economically affordable anatomical kidney phantom with calyxes for

    After the tests with students, six radiologists of the radiology department in East Tallinn Central Hospital were asked to drain a specific calyx on the test phantom (B) † to see the difference between the performance times of the students and every-day-practicing radiologists

  15. Nonvisualized ("phantom") renal calyx: causes and radiological approach

    A calyx which fails completely to opacify on excretory urography (phantom calyx) is often the harbinger of serious underlying renal disease. Causes of a phantom calyx include tuberculosis, tumor, calculus, ischemia, trauma, and congenital anomaly. The pathologic basis for the radiographic findings in each of these entities is described and an ...

  16. Renal Infections and Renal Fungal Infections

    Common sites of tuberculous strictures are the calyceal neck with hydrocalyx (Figs. 5a and 6) or phantom calyx (Figs. 5b-d and 7); the infundibulum of a calyx with hydrocalyx or regional or focal hydrocalycosis (Fig. 8); the ureteropelvic junction with dilatation of the entire renal pelvis, calyces, and infundibula (Fig. 9); and the lower ...

  17. Moscow's scientists create human liver phantom to train doctors

    Moscow's scientists have developed a human liver phantom that resembles the organ both in shape and internal structure for doctors to see ultrasound images of veins, arteries and various formations and train skills of ultrasound-guided abnormality detection and carry out medical procedures. "We do not stop improving the quality of medical ...

  18. Landing Page 2023

    Your Medical Imaging Experts on the Palouse Located in Moscow, Idaho, Palouse Imaging Consultants has provided pioneering medical imaging and interpretation services to the area for more than 50 years. We pair state-of-the-art technology and personalized consultation with physicians, providers, technologists, and patients to provide the absolute best care. Your Medical Imaging Experts on the […]

  19. Contacts of the National Medical Research Radiological Centre of the

    Contact feedback form. In order to objectively and comprehensively review your application within the established time frame, it is necessary to indicate in the text of the application the contact details, the subject of the application (patient's diagnosis / purpose of the application), as well as attach additional documents or materials in electronic form (extracts from the medical history ...

  20. Sergey Morozov

    "I know Sergey Morozov for >20 years. He is an outstanding radiologist and an innovative thinker. Sergey has a deep understanding of the role of advanced technology, including AI, in the future of Medicine and Radiology. A such, he was elected the first President of the European society for AI in Radiology. He is a superb leader and organizer.

  21. Economically affordable anatomical kidney phantom with calyxes for

    The upper surface of the phantom was covered with a pigmented silicone layer (EcoFlex 0030). The three calyxes and corresponding reservoirs were filled with differently colored water. Different colors were used for that it would be possible to check that the correct calyx was punctured and drained. The design of the phantom can be seen in Fig. 1.

  22. Economically affordable anatomical kidney phantom with calyxes for

    BackgroundTrends in interventional radiology and urology training are orientated towards reducing costs and increasing efficiency. In order to comply with the trends, we propose training on inexpen...