Imaging Pearls ❯ Kidney ❯ Inflammatory Disease
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- Dystrophic calcification is the most common type and usually occurs following myocardial infarction. This condition is characterized by the deposition of calcium in the injured myocardium in the setting of normal calcium and phosphorus levels. The prevalence of dystrophic calcifications is estimated to be about 8% in myocardial infarctions older than 6 years . Other causes of dystrophic calcification include trauma, radiation , infectious and/or inflammatory causes, and neoplastic pathology. Rarely, there have been reports where the primary disorders originate from the adjacent myocardial tissue, as recognized in cases like exuberant and extensive mitral annulus calcification , or pericardial calcifi- cation extending into the surrounding myocardium.
Extensive myocardial calcifications in a dialysis patient: A porcelain heart manifesting with abdominal pain
Moezedin Javad Rafiee, et al.
R a d i o l o g y Cas e R e p o r t s 1 9 ( 2 0 2 4 ) 5 2 3 – 5 3 0 - Calcium deposition in otherwise healthy myocardium, indicating a systemic disruption in calcium metabolism. The locations and patterns of this type of calcification vary. It can ap- pear faint or dense and usually presents as nodular and/or amorphous. The deposition may be widespread or localized, affecting a single heart chamber or all of the cavitie . This form is most commonly seen in chronic kidney disease (CKD) with an estimated prevalence of 59% in postmortem studies of those patients with CKD on maintenance hemodialysis [. Other causes include acute kidney disease (AKD), in- creased bone turnover, oxaluria , primary or secondary - hyperparathyroidism related to dietary deficiency of calcium and Vitamin D (11), and other Vitamin D-related disorders [4] . There are multiple CKD and dialysis-related factors contributing to dystrophic calcification, including elevated phosphorus levels, and secondary or tertiary hyperparathyroidism which results in hypercalcemia and culminates in an abnormal calcium and phosphorus homeostasis manifesting as a high product of Calcium-Phosphorus (Ca x PO4) with a normal range is less than 55 mg/dL , as well as side effects of treatment with calcium-containing phosphate binders and vitamin D analogs.
Extensive myocardial calcifications in a dialysis patient: A porcelain heart manifesting with abdominal pain
Moezedin Javad Rafiee, et al.
R a d i o l o g y Cas e R e p o r t s 1 9 ( 2 0 2 4 ) 5 2 3 – 5 3 0 - Cardiovascular disease accounts for more than 50% of deaths in patients with end-stage renal disease (ESRD) receiving dialysis . There are various factors that have been suggested to contribute to elevated risk, but recently roles of dialysis-specific pathogenetic factors such as hyperphosphatemia, hypercalcemia that lead to high levels of serum calcium x phosphorus product(Ca x PO4), and hyperparathyroidism in the development of coronary artery calcification, myocardial calcification and aortic valve calcification has been raised. Regmi et al found that elevated product of serum calcium and phosphorus (Ca x PO4) exceeding 55 mg/dL is an independent risk factor for cardiovascular events in CKD patients.
Extensive myocardial calcifications in a dialysis patient: A porcelain heart manifesting with abdominal pain
Moezedin Javad Rafiee, et al.
R a d i o l o g y Cas e R e p o r t s 1 9 ( 2 0 2 4 ) 5 2 3 – 5 3 0 - The patterns and specific localizations of these calcifications can provide clues into the underlying cause. Generally, dystrophic calcifications have a tendency to be localized and linear, whereas metastatic calcifications may present as dif- fuse, globular, or coarse amorphous patterns [ 2 ,27 ]. Atrial involvement is usually associated with rheumatic heart dis- ease along with mitral valve engagement, but it can also occur in cases of metastatic calcifications. Various pathologies like vascular, valvular, pericardial, and tumoral calcification can mimic myocardial calcification. The morphology and distribution of calcification play a crucial role in discerning the precise anatomical location. For instance, coronary calcifications appear as linear or tram-track patterns along their typical anatomical path, while pericardial calcifications exhibit a curvilinear pattern, often globally involving the pericardium. The application of cardiac CT scans is pivotal for distinguish- ing calcifications situated within the myocardium from those in extramyocardial locations.
Extensive myocardial calcifications in a dialysis patient: A porcelain heart manifesting with abdominal pain
Moezedin Javad Rafiee, et al.
R a d i o l o g y Cas e R e p o r t s 1 9 ( 2 0 2 4 ) 5 2 3 – 530 
Extensive myocardial calcifications in a dialysis patient: A porcelain heart manifesting with abdominal pain
Moezedin Javad Rafiee, et al.
R a d i o l o g y Cas e R e p o r t s 1 9 ( 2 0 2 4 ) 523-530- Similar to the urinary bladder, the vast majority of cases of emphysematous infection of the kidney occur in patients with diabetes mellitus.This is believed to be due to anaerobic metabolism which results in fermentation of lactose and the production of carbon dioxide and hydrogen gases, a process enabled by elevated glucose levels. While the majority of cases are unilateral, with the left kidney affected more commonly than the right, approximately 10% of cases are bilateral, which complicates treatment options which include antibiotics, percutaneous nephrostomy, an emergency nephrectomy as a salvage therapy. The clinical presentation may appear similar to uncomplicated pyelonephritis, and as such, CT imaging is crucial for diagnosis, particular in patients with pyelonephritis who fail to improve with standard antibiotic therapies. Of course, the presence of gas within the kidney is diagnostic; multiple classification systems have been proposed based on varying amounts of renal and perirenal gas involvement.
A pictorial review of genitourinary infections and inflammations
Mark McArthur , Maitraya Patel
Clinical Imaging 104 (2023) 110013 - “IgG4-related disease is a recently recognized and poorly understood disease of unknown etiology which results in the systemic proliferation of IgG4-positive plasma cells. The first organ to be described with involvement by IgG4 disease was the pancreas in 2001; but since then, IgG4 proliferation has been described in nearly every organ system, including the kidneys. While elevated IgG4 serum levels may be useful in diagnosing the disease, it is important to note that not all patients will present with elevated IgG4. In addition, IgG4-positive plasma cell infiltration may also be seen in numerous other disorders such as Castleman's disease. On imaging, the disease may present with three different mildly-enhancing lesions patterns: round, wedge-shaped, or diffuse patchy infiltration and may be seen in the renal parenchyma, pelvis, or perinephric space .”
A pictorial review of genitourinary infections and inflammations
Mark McArthur , Maitraya Patel
Clinical Imaging 104 (2023) 110013
- “XGP is an aggressive variant of chronic pyelonephritis resulting in a non-functioning kidney XGP accounts for 0.6–1% of renal inflammatory diseases; however, our rate of XGP was 43.9% among benign nephrectomies for renal inflammatory disease, and it was much greater than that previously reported.”
MDCT Diagnosis and Staging of Xanthogranulomatous Pyelonephritis
Stefania Tamburrini et al.
Diagnostics 2023, 13, 1340. - “The pathomechanism of XGP is not fully understood. Many factors are implicated: chronic obstructive disease with ongoing ineffectively treated chronic urinary infections, an altered immune response, and disorders of lipid metabolism. Calculi serve as a nidus for infection; organisms most commonly associated with XGP are Escherichia coli, Proteus mirabilis, Pseudomonas, Enterococcus faecalis, and Klebsiella. Renal parenchyma and peri-renal tissue are destructed and replaced by granulomatous tissue containing lipid-laden macrophages that appear yellow in the pathological section .”
MDCT Diagnosis and Staging of Xanthogranulomatous Pyelonephritis
Stefania Tamburrini et al.
Diagnostics 2023, 13, 1340. - “Although XGP is considered a rare disease, at our institution, it represented 43.90% among benign nephrectomies. XGP is related to stone disease in 83.33% of cases. As described in other studies, we found a population that consisted largely of middle-aged women presenting with nonspecific symptoms and laboratory values. CT diagnostic accuracy for kidney inflammatory disease was extremely high, whereas the suspected diagnosis of XGP was formulated preoperatively in only 66.67% of high-stage diseases, where the hallmarks of invasiveness and fistulization of the pathology increased the diagnostic confidence. The stage I-nephric form of XGP could not be differentiated, based on imaging, from other renal inflammatory disease. The “bear paw “sign remains the more characteristic finding of CT (72.22%) in XGP; meanwhile, the presence of xanthomas, although considered pathognomic, cannot be reliable for the diagnosis because it is extremely rare (5.56%).”
MDCT Diagnosis and Staging of Xanthogranulomatous Pyelonephritis
Stefania Tamburrini et al.
Diagnostics 2023, 13, 1340.
- “Nephrotoxicity due to long-term lithium therapy is a well-described entity and is divided into three main categories: acute intoxication, nephrogenic diabetes insipidus, and chronic renal disease. Nephrogenic diabetes insipidus is the most common complication of lithium-induced nephrotoxicity and typically is reversible with drug cessation. However, patients who undergo long-term lithium therapy may develop chronic focal interstitial nephritis that results in progressive, nonreversible, chronic renal insufficiency. In the setting of progressive renal dysfunction and lithium therapy, clinical and laboratory data typically are sufficient to establish the diagnosis. However, if a renal biopsy is performed, it will show tubular atrophy, glomerulosclerosis, interstitial fibrosis, and distal tubular dilatation with microcyst formation.”
CT and MR Imaging for Evaluation of Cystic Renal Lesions and Diseases
Cecil G. Wood et al.
RadioGraphics 2015; 35:125–141 - “CT and MR imaging findings of lithium induced nephrotoxicity typically include normalized kidneys with abundant and uniformly distributed renal microcysts. Microcysts have been reported in 33%–62% of patients who are undergoing lithium therapy. These cysts are found in the cortex and medulla and typically are 1–2 mm in diameter. At CT, the cysts appear as multiple tiny hypoattenuating lesions.”
CT and MR Imaging for Evaluation of Cystic Renal Lesions and Diseases
Cecil G. Wood et al.
RadioGraphics 2015; 35:125–141 - “The differential diagnosis includes ADPKD, GCKD, medullary cystic kidney disease, and acquired cystic kidney disease. These entities can usually be differentiated from lithium-induced nephrotoxicity on the basis of clinical history as well as the size and distribution of cysts at imaging .”
CT and MR Imaging for Evaluation of Cystic Renal Lesions and Diseases
Cecil G. Wood et al.
RadioGraphics 2015; 35:125–141
- Purpose To describe the urological manifestations of Erdheim–Chester disease (ECD) and their computed tomography (CT) findings.
Methods We retrospectively reviewed 48 patients diagnosed with ECD at Peking Union Medical College Hospital from January 2014 to January 2020. Twenty-four patients exhibited urological manifestations. Their CT findings, including appear- ances of the involved area (e.g., perirenal space, renal sinus, ureters, renal arteries, and adrenal glands), occurrence rate of ECD involvement in each area, signal enhancement pattern after CT contrast agent administration, disease progression, and causes of hydronephrosis were discussed.
Results In 24 patients with evidence of ECD urological involvement, the most common manifestation was perirenal infiltra- tion, appearing as “hairy kidney” on unenhanced CT scans and moderate signal enhancement on enhanced CT scans (17/24, 70.8%). Other manifestations included renal sinus infiltration (16/24, 66.7%), proximal ureter involvement (14, 58.3%), renal artery sheath (10, 41.7%), hydronephrosis (14, 58.3%), and adrenal glands involvement (8, 33.3%). The histiocytic infiltrate was mostly bilateral, starting from the perirenal space and spreading to the renal sinus and ureters. Hydronephrosis was usually associated with infiltration of ureters.
Conclusion Kidneys are the most common visceral organs affected by ECD. CT scanning is not only advantageous in early diagnosis, but also critical for designing the treatment regime for patients with ECD.
Urinary involvement in Erdheim–Chester disease: computed tomography imaging findings
Zhe Wu et al.
Abdominal Radiology (2021) 46:4324–4331 - Purpose To describe the urological manifestations of Erdheim–Chester disease (ECD) and their computed tomography (CT) findings.
Results In 24 patients with evidence of ECD urological involvement, the most common manifestation was perirenal infiltration, appearing as “hairy kidney” on unenhanced CT scans and moderate signal enhancement on enhanced CT scans (17/24, 70.8%). Other manifestations included renal sinus infiltration (16/24, 66.7%), proximal ureter involvement (14, 58.3%), renal artery sheath (10, 41.7%), hydronephrosis (14, 58.3%), and adrenal glands involvement (8, 33.3%). The histiocytic infiltrate was mostly bilateral, starting from the perirenal space and spreading to the renal sinus and ureters. Hydronephrosis was usually associated with infiltration of ureters.
Conclusion Kidneys are the most common visceral organs affected by ECD. CT scanning is not only advantageous in early diagnosis, but also critical for designing the treatment regime for patients with ECD.
Urinary involvement in Erdheim–Chester disease: computed tomography imaging findings
Zhe Wu et al.
Abdominal Radiology (2021) 46:4324–4331
- "CT urography demonstrates ureteral mural thickening with periureteral inflammatory changes. Tuberculosis tends to involve distal third of the ureter and causes multiple strictures and fibrotic changes with disease progression resulting in a characteristic “beaded or corkscrew” appearance . Chronic mural thickening of the ureter results in foreshortening and “pipestem” ureter. Tuberculosis may also present as pseudotumor due to inflammatory ureteral mural thickening and would be difficult to distinguish from malignancy on imaging . In a small number of cases, ureteral calcifications can be seen.”
Imaging of ureter: a primer for the emergency radiologist
Mohd Zahid et al.
Emerg Radiol (2021). https://doi.org/10.1007/s10140-021-01930-5 - "Genitourinary tuberculosis is the second most common form of extrapulmonary tuberculosis and usually caused by hematogenous dissemination. It accounts for 15–20% of all extrapulmonary tuberculosis cases. Genitourinary tuberculosis involves the ureter in approximately 50% of the cases. In early disease, IVU or retrograde urography shows ragged and dilated ureter and occasional filling defects of mucosal granulomas.”
Imaging of ureter: a primer for the emergency radiologist
Mohd Zahid et al.
Emerg Radiol (2021). https://doi.org/10.1007/s10140-021-01930-5 
Imaging of ureter: a primer for the emergency radiologist
Mohd Zahid et al.
Emerg Radiol (2021). https://doi.org/10.1007/s10140-021-01930-5
- “Sickle cell disease (SCD), one of the most common inherited genetic syndromes in the USA, is characterized by recurring episodes of acute illness and progressive multisystem organ injury. Individuals with SCD frequently present to the emergency department for a spectrum of complications, such as vaso-occlusive crises, infection, cholecystitis, and stroke. Imaging correlates for most of these presentations exist, positioning the emergency radiologist to play a pivotal role in facilitating patient care. Using a systems-based approach, we describe the acute and chronic imaging manifestations of SCD that an emergency radiologist can expect to encounter in most practice settings, highlighting the unique pathophysiology of this disorder that typically underlies the imaging findings.”
Imaging review of sickle cell disease for the emergency radiologist
Shenise N. Gilyard et al.
Emergency Radiology (2021) 28:153–164 - "Early renal manifestations of SCD include hyposthenuria (inability to concentrate urine), polyuria, and enuresis. Later complications include proteinuria, nephrotic syndrome, hematuria, and papillary necrosis. Approximately 50% of in- dividuals with SCD have enlarged kidneys on imaging, likely related to increased renal blood volume and glomerular hypertrophy.
Imaging review of sickle cell disease for the emergency radiologist
Shenise N. Gilyard et al.
Emergency Radiology (2021) 28:153–164 - “Two important entities with a particular association with SCD include segmental infarction and papillary necrosis. As with any other solid abdominal organ, acute renal infarction appears as peripheral, wedge-shaped hypoattenuating areas on contrast- enhanced CT and may be associated with mild mass effect from edema. Perirenal hematomas can rarely occur in acute renal infarction. Remote infarcts are characterized by focal cortical scarring. It is estimated that renal papillary necrosis affects up to 50% of individuals with SCD. Papillary necrosis is optimally depicted on excretory phase contrast-enhanced CT as calyceal blunting or excreted contrast enveloping necrotic, sloughed papillae (golf ball-on-tee sign).”
Imaging review of sickle cell disease for the emergency radiologist
Shenise N. Gilyard et al.
Emergency Radiology (2021) 28:153–164
- “Contrast-enhanced CT is the imaging modality of choice for the evaluation of pyelonephritis, as it has higher sensitivity (87%) for the detection of pyelonephritis and other urinary tract abnormalities such as nephrolithiasis, hydronephrosis, and perinephric abscess. Portal venous phase CT images may show a wedge-shaped pattern of infiltration, manifesting as parenchymal hypoperfusion or a striated nephrogram appearance. MRI, which is most commonly used only in special populations such as children and pregnant patients, also may show wedge-shaped or striated nephrogram patterns of parenchymal hypoenhancement.”
Infiltrative Renal Malignancies: Imaging Features, Prognostic Implications, and Mimics
Sweet DE et al.
RadioGraphics 2021; 41:0000–0000 - “Xanthogranulomatous pyelonephritis (XGP) is a chronic destructive granulomatous process that results from chronic or recurrent urinary tract infection, most commonly with Proteus mirabilis or E coli bacteria. XGP is uncommon, accounting for approximately 0.6% of histologically documented cases of pyelonephritis. This condition is more common in women and typically manifests as fever, flank or abdominal pain, and a palpable mass. XGP is an important diagnosis to recognize, as a delayed diagnosis can lead to complete destruction of the kidney and injury to adjacent organs and viscera, such as involvement of the psoas muscle or development of a gastrointestinal fistula. The treatment of XGP is nephrectomy, with conservative nephron-sparing approaches appropriate only in cases with focal involvement.”
Infiltrative Renal Malignancies: Imaging Features, Prognostic Implications, and Mimics
Sweet DE et al.
RadioGraphics 2021; 41:0000–0000 - “At imaging, XGP is characterized by reniform enlargement of the kidney, with poorly marginated parenchymal abnormalities that correspond to areas of inflammation that may extend into the perinephric spaces. This ill-defined infiltrative pattern can be mistaken for infiltrative malignancy, especially in cases of focal XGP. There is typically marked dilatation of the calyces and cortical thinning with central obstructing calculi, often with staghorn morphology. The majority of cases (73%–100%) have an associated renal calculus (either calyceal or staghorn). In one study, the classic “bear paw” appearance was present in only 23% of cases.”
Infiltrative Renal Malignancies: Imaging Features, Prognostic Implications, and Mimics
Sweet DE et al.
RadioGraphics 2021; 41:0000–0000
- “Thalassemia is a kind of chronic, inherited, microcytic anemia characterized by defective hemoglobin synthesis and ineffective erythropoiesis. In all thalassemias clinical features that result from anemia, transfusional, and absorptive iron overload are similar but vary in severity. The radiographic features of b-thalassemia are due in large part to marrow hyperplasia. Markedly expanded marrow space lead to various skeletal manifestations including spine, skull, facial bones, and ribs. Extramedullary hematopoiesis (ExmH), hemosiderosis, and cholelithiasis are among the non-skeletal manifestations of thalassemia.”
Imaging features of thalassemia
M. Tunacõ, A. Tunacõ, G. Engin et al.
Eur. Radiol. 9, 1804±1809 (1999)
- “Genitourinary tuberculosis almost always starts in the kidney, which is infected by hematogenous dissemination from primary pulmonary tuberculosis. Ureteral and bladder involvement is almost always secondary to renal involvement, arising from seeding of the ureter and bladder from the infected kidney.”
Imaging Findings of Urinary Tuberculosis on Excretory Urography and Computerized Tomography
Wang LJ et al.
The Journal of Urology Volume 169, Issue 2, February 2003, Pages 524–528 - “On CT renal parenchymal scarring was the most common finding (76% of cases), followed by hydrocalycosis, hydronephrosis or hydroureter due to stricture (67%) and thick walls of the renal pelvis, ureters or bladder (61%). The stricture site on CT was the infundibulum in 12 cases, ureteropelvic junction in 6 and ureter in 22. Thick walls were visualized on CT in the renal pelvis in 15 images, ureters in 16 and bladder in 7. Renal calcifications were identified on CT at the renal parenchyma in 10 cases, renal collecting system wall in 2 and at each site.”
Imaging Findings of Urinary Tuberculosis on Excretory Urography and Computerized Tomography
Wang LJ et al.
The Journal of Urology Volume 169, Issue 2, February 2003, Pages 524–528 - “IVP and CT showed a wide spectrum of imaging findings of urinary tuberculosis in our study. Of these findings renal parenchymal masses and scarring, thick urinary tract walls and extra-urinary tubercular manifestations were more common on CT than on IVP. Although each imaging finding may be nonspecific, multiple findings on IVP and CT were common in our study. When the 3 patterns of multiple findings are shown on IVP and CT, tubercular cultures or biopsy specimens are suggested to make the definite diagnosis.”
Imaging Findings of Urinary Tuberculosis on Excretory Urography and Computerized Tomography
Wang LJ et al.
The Journal of Urology Volume 169, Issue 2, February 2003, Pages 524–528 - “The 3 imaging patterns were hydrocalycosis, hydronephrosis or hydroureter due to multiple strictures, hydrocalycosis, hydronephrosis or hydroureter due to a single stricture with at least 1 other imaging finding and autonephrectomy with another imaging finding other than stricture.”
Imaging Findings of Urinary Tuberculosis on Excretory Urography and Computerized Tomography
Wang LJ et al.
The Journal of Urology Volume 169, Issue 2, February 2003, Pages 524–528
- “Tuberculosis demonstrates a variety of radiologic features depending on the organ involved and can mimic a number of other disease entities. Cross-sectional imaging alone is insufficient in reaching a conclusive diagnosis. Tuberculosis is a great mimicker as its radiologic manifestations can simulate numerous other diseases across the body systems. However, recognition and understanding of the common and uncommon radiologic manifestations of tuberculosis should alert considering tuberculosis in the high-risk population and correct clinical setting to enable appropriate treatment.”
Tuberculosis—The Great Mimicker
Prapruttam D et al.
Semin Ultrasound CT MRI 35:195-214 - "CT findings include hypodense parenchymal lesions, miliary nodules, and renal abscess. Focal nephritis appears as wedge-shaped areas of reduced enhancement, which is identical in appearance to nephritis caused by other organisms. The earliest change in the upper collecting system is papillary necrosis, which on CT may appear as triangular or ringlike calcifications within the renal collecting system. Renal calcifications secondary to immune response are a common finding.”
Tuberculosis—The Great Mimicker
Prapruttam D et al.
Semin Ultrasound CT MRI 35:195-214 - "Ongoing infection and immune reaction lead to parenchymal scarring and eventually to a nonfunctioning kidney with dense globular calcifications, referred to as a “putty kidney”. CT urography is helpful in demonstrating collecting system involvement, including abnormal urothelial thickening and enhancement, caliectasis, infundibular stricturing, and hydronephrosis.”
Tuberculosis—The Great Mimicker
Prapruttam D et al.
Semin Ultrasound CT MRI 35:195-214
- “Erdheim-Chester disease is a non–Langerhans cell histiocytosis characterized by the infiltration of foamy histiocytes with fibrosis that can affect many organs, most commonly long bones.Renal involvement commonly manifests in this disease as a histiocytic infiltration into the perirenal fat. Histopathologic findings from biopsy of the right retroperitoneal region included fragments of fibroadipose tissue displaying a lymphohistiocytic infiltrate.”
The Hairy Kidney of Erdheim-Chester Disease
Scolaro JC, Peiris AN
Mayo Clin Proceed May 2018Volume 93, Issue 5, Page 671 - “Peripelvic and periureteric areas are frequently overlooked in the imaging evaluations of the urinary system on computed tomography and magnetic resonance imaging. Several neoplastic and non-neoplastic disorders and diseases including lipomatosis, angiomyolipoma and angiolipomatous proliferation, vascular lesions, lymphangiomatosis, Rosai-Dorfman disease, Erdheim-Chester disease, extramedullary hematopoiesis, IgG4-related disease, lymphoma, mesenchymal tumors, trauma, and Antopol-Goldman lesion may involve these areas. Differentiation of these benign or malignant pathologies among themselves and from primary renal pathologies is of utmost importance to expedite the triage of patients for correct treatment approach.”
Computed tomography and magnetic resonance imaging of peripelvic and periureteric pathologies.
Gumeler E et al.
Abdom Radiol (NY). 2018 Sep;43(9):2400-2411 - “Erdheim–Chester disease (ECD) is first described by Jacob Erdheim and William Chester in 1930 and is also referred to as lipogranulomatosis. ECD is a systemic inflammatory disorder with a poor prognosis. Skeletal system is the most commonly involved body part, however, around 50% of the cases may have extraskeletal involvement. Symmetrical diaphyseal and metaphyseal osteosclerosis of the long bones is the typical skeletal finding. Among the extraskeletal sites that are involved central nervous system, pulmonary and cardiovascular systems, orbital cavity and cutaneous system may be counted in addition to the kidneys and the retroperitoneum.”
Computed tomography and magnetic resonance imaging of peripelvic and periureteric pathologies.
Gumeler E et al.
Abdom Radiol (NY). 2018 Sep;43(9):2400-2411 - "Urological manifestations of ECD may include, but not limited to, ureteral obstruction secondary to retroperitoneal involvement, primary adrenal and kidney involvement. Adrenal and renal failure may occur in some of the affected patients. Perirenal soft tissue infiltration is reported as the most frequently observed form of retroperitoneal involvement.”
Computed tomography and magnetic resonance imaging of peripelvic and periureteric pathologies.
Gumeler E et al.
Abdom Radiol (NY). 2018 Sep;43(9):2400-2411 - “For genitourinary system evaluation in patients with ECD, CT may be utilized as the first modality of choice. The so called “hairy kidney appearance,” due to perirenal involvement, is typically characterized by hypoattenuating, irregularly shaped soft tissue masses with minimal enhancement after contrast injection. This finding is very frequent in cases with renal ECD, with a reported rate of 68% of all patients with genitourinary involvement. Infiltrative extension towards the kidney periphery into the renal sinus may be observed.”
Computed tomography and magnetic resonance imaging of peripelvic and periureteric pathologies.
Gumeler E et al.
Abdom Radiol (NY). 2018 Sep;43(9):2400-2411 - “Erdheim–Chester disease (ECD) is a rare xanthogranulomatous histiocytosis of non-Langerhans cells most common in male adults between the fourth and seventh decades of life. It was first described by Erdheim and Chester in 1930 and is characterized by multifocal osteosclerotic lesions of the long bones.Although there is a speculation that ECD and other histiocytic disorders may represent an aberrant response to infection, no infectious etiology has been identified. It remains controversial if ECD is a reactive polyclonal histiocyte proliferation or a monoclonal neoplastic process.”
Spectrum of abdominal imaging findings in histiocytic disorders.
de Souza Maciel Rocha Horvat, N., Coelho, C.R., Roza, L.C. et al.
Abdom Imaging 40, 2738–2746 (2015). https://doi.org/10.1007/s00261-015-0449-1 - "Infiltration of the perirenal fat appears as an irregular renal border producing a “hairy kidney” appearance on CT and MRI. On CT, this manifests as a hypodense and homogeneous band with spiculated contours and mild contrast enhancement. On MRI, it is isointense to muscle on T1- and T2-weighted sequences, with a slight and homogeneous enhancement after contrast injection. Perirenal infiltration may progress to the renal sinuses and produce a post renal obstruction. The ureteral segments which are most commonly affected by fibrosis are the middle and distal segments. The renal arteries may also be involved by tissue infiltration and fibrosis.”
Spectrum of abdominal imaging findings in histiocytic disorders.
de Souza Maciel Rocha Horvat, N., Coelho, C.R., Roza, L.C. et al.
Abdom Imaging 40, 2738–2746 (2015). https://doi.org/10.1007/s00261-015-0449-1 - "Retroperitoneal involvement with ECD can manifest as a mass-like infiltrative surrounding the abdominal aorta with the same characteristics of the perirenal lesions. This can lead to acute or slowly progressive renal insufficiency. Retroperitoneal involvement frequently includes a bilateral, symmetric, and diffuse thickening of the adrenal glands associated with infiltration of the adjacent fat.”
Spectrum of abdominal imaging findings in histiocytic disorders.
de Souza Maciel Rocha Horvat, N., Coelho, C.R., Roza, L.C. et al.
Abdom Imaging 40, 2738–2746 (2015). https://doi.org/10.1007/s00261-015-0449-1 - Erdheim Chester Disease: Renal Changes
- Perirenal fat effaced or infiltrated by soft tissue
- Usually bilateral and symmetric
- Infiltration of para-aortic regions is also common - Erdheim Chester Disease: Vascular Changes
- Periaortic infiltration which is usually circumferential and nonocclusive
- May involve aorta from root thru iliac vessels - Perinephric Masses on CT: Differential Diagnosis
- Lymphoma
- Metastases (especially melanoma)
- Myeloma
- Urinomas
- Hemmorrhage
- Infection
- Extramedullary hematopoiesis
- Retroperitoneal fibrosis
- Erdheim Chester disease - Perirenal Space Pathology
- Solitary soft tissue masses (RCC, lymphangioma,hemangioma)
Rindlike soft tissue lesions (lymphoma, retroperitoneal fibrosis, Erdheim Chester disease)
- Multifocal soft tissue masses (metastases)
- Masses containing macroscopic fat (AML, extramedullary hematopoiesis)
Neoplastic and Nonneoplastic Proliferative Disorders of the Perirenal Space: Cross-sectional Imaging Findings
Surabhi VR et al
RadioGraphics 2008; 28:1005-1017
- “Genitourinary tuberculosis almost always starts in the kidney, which is infected by hematogenous dissemination from primary pulmonary tuberculosis. Ureteral and bladder involvement is almost always secondary to renal involvement, arising from seeding of the ureter and bladder from the infected kidney.”
Imaging Findings of Urinary Tuberculosis on Excretory Urography and Computerized Tomography Wang LJ et al. The Journal of Urology Volume 169, Issue 2, February 2003, Pages 524–528 - “On CT renal parenchymal scarring was the most common finding (76% of cases), followed by hydrocalycosis, hydronephrosis or hydroureter due to stricture (67%) and thick walls of the renal pelvis, ureters or bladder (61%). The stricture site on CT was the infundibulum in 12 cases, ureteropelvic junction in 6 and ureter in 22. Thick walls were visualized on CT in the renal pelvis in 15 images, ureters in 16 and bladder in 7. Renal calcifications were identified on CT at the renal parenchyma in 10 cases, renal collecting system wall in 2 and at each site.”
Imaging Findings of Urinary Tuberculosis on Excretory Urography and Computerized Tomography Wang LJ et al. The Journal of Urology Volume 169, Issue 2, February 2003, Pages 524–528 - “IVP and CT showed a wide spectrum of imaging findings of urinary tuberculosis in our study. Of these findings renal parenchymal masses and scarring, thick urinary tract walls and extra-urinary tubercular manifestations were more common on CT than on IVP. Although each imaging finding may be nonspecific, multiple findings on IVP and CT were common in our study. When the 3 patterns of multiple findings are shown on IVP and CT, tubercular cultures or biopsy specimens are suggested to make the definite diagnosis.”
Imaging Findings of Urinary Tuberculosis on Excretory Urography and Computerized Tomography Wang LJ et al. The Journal of Urology Volume 169, Issue 2, February 2003, Pages 524–528 - “The 3 imaging patterns were hydrocalycosis, hydronephrosis or hydroureter due to multiple strictures, hydrocalycosis, hydronephrosis or hydroureter due to a single stricture with at least 1 other imaging finding and autonephrectomy with another imaging finding other than stricture.”
Imaging Findings of Urinary Tuberculosis on Excretory Urography and Computerized Tomography Wang LJ et al. The Journal of Urology Volume 169, Issue 2, February 2003, Pages 524–528
- Acute Pyelonephritis: Facts
• More common in woman
• Usually due to e.coli infection
• In most cases initial CT imaging is not necessary unless complications expected like in diabetic, elderly, or immunocompromised or have a history of stone disease and congenital GU abnormalities. - Striated Nephrogram: Differential Dx
• Acute pyelonephritis
• CT contrast toxicity
• Renal infarctsrenal infiltrative process (leukemia, lymphoma)
• Transitional cell carcinoma - Renal Vein Thrombosis: Facts
• Symptoms include flank pain, microscopic hematuria, and deterioration of renal function
• common causes for RVT are extension of renal tumor, trauma, or a hypercoagulable state as seen in nephrotic syndrome (ie, membranous glomerulonephritis), systemic lupus erythematosus, or an inherited syndrome. Renal vein thrombus occurs in 20% of patients with nephrotic syndrome
- “Renal papillary necrosis is not a pathologic entity but rather a descriptive term for a condition—necrosis of the renal papillae—that has various possible causes. The renal medulla and papillae are vulnerable to ischemic necrosis because of the peculiar arrangement of their blood supply and the hypertonic environment. The etiology of renal papillary necrosis includes diabetes, analgesic abuse or overuse, sickle cell disease, pyelonephritis, renal vein thrombosis, tuberculosis, and obstructive uropathy.”
Renal papillary necrosis: review and comparison of findings at multi-detector row CT and intravenous urography.
Jung DC et al.
Radiographics. 2006 Nov-Dec;26(6):1827-36. - “Renal papillary necrosis has been diagnosed with the use of intravenous urography and ultrasonography, but contrast material-enhanced computed tomography (CT) may better depict a full range of typical features, including contrast material-filled clefts in the renal medulla, nonenhanced lesions surrounded by rings of excreted contrast material, and hyperattenuated medullary calcifications. In the presence of papillary sloughing, CT may depict hydronephrosis and filling defects in the renal pelvis or ureter, which also may contain calcifications.”
Renal papillary necrosis: review and comparison of findings at multi-detector row CT and intravenous urography.
Jung DC et al.
Radiographics. 2006 Nov-Dec;26(6):1827-36. - “Renal papillary necrosis has a wide range of causes, including diabetes, analgesic abuse or overuse, sickle cell disease, pyelonephritis, renal vein thrombosis, tuberculosis, and obstructive uropathy. The most common of these diseases among adults is diabetes, which often is associated with urinary tract infection and impaired renal function but which may be present also in patients without any apparent diabetic nephropathy. Analgesic nephropathy is caused by the excessive intake of analgesics and is most common in middle-aged women.”
Renal papillary necrosis: review and comparison of findings at multi-detector row CT and intravenous urography.
Jung DC et al.
Radiographics. 2006 Nov-Dec;26(6):1827-36. - “Renal papillary necrosis results from ischemia in the renal papillae in a variety of diseases. Multi–detector row CT, unlike excretory urography, can help identify renal papillary necrosis at an early stage, when effective treatment of the underlying cause may reverse the ischemic process. Multi–detector row CT, more clearly and directly than single–detector row CT, depicts classic signs of renal papillary necrosis such as excavation of calices, regression of papillae, sloughed papillae floating in the collecting system or ureter, caliceal blunting at the papillary tip, and evidence of progression and involvement of the cortex with pyelonephritic scarring.”
Renal papillary necrosis: review and comparison of findings at multi-detector row CT and intravenous urography.
Jung DC et al.
Radiographics. 2006 Nov-Dec;26(6):1827-36.
- Xanthogranulomatous Pyelonephritis: Facts
- Large staghorn calculus in most, but not all cases with contracted pelvis
- Extensive inflammatory process
- Decreased renal function
- Enlarged kidneys
- Severe hydronephrosis, expansion of calices
- Can be associated with extrarenal disease
- Psoas involvement - Xanthogranulomatous Pyelonephritis: Facts
- Chronic destructive granulomatous process
- Results from atypical incomplete immune response to a subacute bacterial infection
- Parenchyma replaced by lipid-laden macrophages
- Diabetes in only 10%
- F>M, more common in middle age
- 90% pyuria, 60% + cultures, hematuria 18% - “ Presenting signs and symptoms included pain (66%), urinary frequency (66%), dysuria (66%), nocturia (66%), palpable mass (56%), leukocytosis (50%), and fever (50%). The duration of symptoms was usually relatively short (less than 6 months), considering the extent of the pathologic process.”
CT of xanthogranulomatous pyelonephritis: radiologic-pathologic correlation.
Goldman SM, Hartman DS, Fishman EK, et al.
AJR Am J Roentgenol. 1984 May;142(5):963-9. - “There was CT identification of unsuspected extension through the renal capsule with involvement of the perirenal space in 11 patients, the pararenal spaces in 13, and the psoas muscle in six. The pararenal space and the psoas muscle were often extensively involved with minimal perirenal disease in six patients, a reflection of chronic indolent infection.”
CT of xanthogranulomatous pyelonephritis: radiologic-pathologic correlation.
Goldman SM, Hartman DS, Fishman EK, et al.
AJR Am J Roentgenol. 1984 May;142(5):963-9.
- Reverse Rim Nephrogram
- Enhancement of medulla and no enhancement of the cortex
- Usually due to acute cortical necrosis which is a rare form of acute renal failure
- Acute cortical necrosis can be due to prolonged hypotension, transfusion reaction, transplant rejection
- Necrotic cortex will appear as a hypodense rim surrounding the perfused medulla. It may then calcify in time
- Erdheim Chester Disease: Renal Changes
- Perirenal fat effaced or infiltrated by soft tissue
- Usually bilateral and symmetric
- Infiltration of para-aortic regions is also common - How large is a normal Ureter on CT-
- “The mean size of ureters on the asymptomatic side was 1.8 mm with a stan- dard deviation (SD) of 0.9 mm. The mean size of ureters on the obstructed side was 7 mm with an SD of 3.2 mm. In 96% of patients, the ureter diameter on the asymptomatic side was 3 mm or smaller.”
Normal Ureter Size on Unenhanced Helical CT
Zelenko N et al.
AJR 2004; 182:1039-1041 - “The mean size of ureters on the asymptomatic side was 1.8 mm with a standard deviation (SD) of 0.9 mm. The mean size of ureters on the obstructed side was 7 mm with an SD of 3.2 mm. In 96% of patients, the ureter diameter on the asymptomatic side was 3 mm or smaller.”
Normal Ureter Size on on Unenhanced Helical CT
Zelenko n et al.
AJR 2004;182:1039–1041 - “In view of the fact that correctly identifying ureteral dilatation may be crucial to arrive at a correct diagnosis, the need for a definition of what constitutes ureteral dilatation on unenhanced CT is clear. On the basis of the results of this study, we have established 3 mm as the upper limit of normal for ureter diameter on unenhanced CT. Although for many cases reliance on such a measurement will be unnecessary, in the more complex cases and for more inexperienced observers, such a measurement may be helpful.”
Normal Ureter Size on on Unenhanced Helical CT
Zelenko n et al.
AJR 2004;182:1039–1041