Computed tomography of renal inflammatory disease

A Rare Case Report on Xanthogranulomatous Osteomyelitis of Hip Mimicking Tuberculosis and Review of Literature

Xanthogranulomatous osteomyelitis (XO) is a rare chronic inflammatory process characterized by the presence of a large number of lipid-containing macrophages with lymphocytes and plasma cells. We present a case of XO of the hip in a 50-year-old woman with pain in the left hip for 28 months. The patient had a history of taking anti-tuberculosis chemotherapy for five months. Laboratory data revealed an increased erythrocyte sedimentation rate and C-reactive protein (CRP) level. Plain radiographs showed the destruction of the femoral head with arthritis and subluxation. Magnetic resonance imaging (MRI) was suggestive of tubercular infection of the left hip and a benign lesion in the left ilium. The histopathologic examination of the specimen demonstrated the presence of dead bone surrounded by lymph-plasma cells, foamy cells, and histocytes, which was consistent with XO, and culture was positive for Staphylococcus aureus infection. The patient was successfully treated with resection arthroplasty and antibiotics. It is important for the surgeons to keep XO in the list of differentials in cases with lytic lesions of bone and assessment should include microbiological culture along with the biopsy.

Xanthogranulomatous inflammation involving latissimus dorsi donor site and implant breast reconstruction: case report and literature review

Xanthogranulomatous inflammation is a rare clinico-pathological condition involving many organ systems. Breast involvement with this rare condition reported from a few cases of mastitis has been limited to only microscopic involvement on histology. We would like to report an unusual presentation of this inflammatory process presenting as a solid lump mimicking malignancy in latissimus dorsi donor site scar and implant-based breast reconstruction as a result of a ruptured silicone gel implant. To our knowledge there have been no previous reports on similar presentation published in the literature. This case highlights a rare complication of a leaked silicone gel implant triggering a xanthomatous response in the absence of the usual infective or obstructing etiologies. This condition is of benign nature with complete clearance on surgical excision and excellent clinical prognosis reported from other organ involvement.

Diagnosing Acute Pyelonephritis with CT, Tc-DMSA SPECT, and Doppler Ultrasound: A Comparative Study

Purpose

With growing interest in early imaging, the aim of our study was to define the most practical modality for routine clinical use for the diagnosis of acute pyelonephritis (APN). We compared the sensitivity of enhanced computerized tomography (CT), dimercaptosuccinic acid (DMSA) scintigraphy, and Doppler ultrasonography (DUS) by using clinical findings as the standard of reference.

Materials and Methods

A total of 207 APN patients (191 women, 16 men; mean age, 49.4 years; range, 17-88 years) were enrolled in this study. All the patients underwent imaging modalities during hospitalization. SPECT images were obtained 4 hours after injection of ^99mTc-DMSA. Transverse and coronary CT images were obtained before and after injection of the contrast agent. DUS was performed in the longitudinal, transverse, and coronal planes. All the images were read independently by a single radiologist and a nuclear medicine specialist. The sensitivity of each modality for detecting APN was compared.

Results

CT showed significantly superior sensitivity compared with that of DUS (81.0% vs. 33.3%, respectively, n=147). DMSA scintigraphy also showed significantly superior sensitivity compared with that of DUS (74.7% vs. 33.3%, respectively, n=150). Compared with DMSA scintigraphy, CT showed superior sensitivity, but the difference was not statistically significant (81.0% vs. 74.8%, respectively, n=147, p=0.163).

Conclusions

For cases of clinically suspected APN, CT and DMSA scintigraphy appear to be equally sensitive and reliable for detecting APN, although CT is more practical in various fields. DUS was significantly less sensitive.

Multidetector CT urography: techniques, clinical applications, and pitfalls

For two decades, computed tomography (CT) has challenged intravenous urography (IVU) in the evaluation of urinary tract abnormalities. Compared with IVU, CT is more sensitive and specific in the detection and characterization of a variety of urinary tract disorders, including renal masses and urolithiasis. The last purported advantage of IVU has been its ability to depict subtle and mucosal abnormalities of the urothelium. Now, using multidetector CT (MDCT), this challenge has been overcome. In this article, we review the current role of MDCT urography in the evaluation of the urinary tract.

Emergent surgical complications of genitourinary infections

The entities described in this article represent processes that arise from, or can be mistaken for, common GU infections. It might be difficult to determine the point at which pyelonephritis develops into EPN or perinephric abscess. It might be equally challenging to distinguish scrotal cellulitis from Fournier's gangrene; however, as most EPs will acknowledge, the mere awareness of these entities in the appropriate clinical circumstances might be enough to prevent a "near-miss" of a surgical emergency.

Radiologic evaluation of patients with renal infections

Although renal imaging is not indicated routinely in cases of uncomplicated renal infection, CT is a highly sensitive modality to diagnose and guide the management of patients with acute renal infection. CT is particularly useful in identifying complications of renal infection. Intravenous urography and US are limited to screening for urinary obstruction, renal calculi, and underlying anomalies. CT is also of value in establishing the diagnosis in equivocal cases, in evaluating high-risk patients, and in determining the nature and extent of disease. CT urography is increasingly performed as a comprehensive urinary tract imaging study. MRI may be performed when patients have contraindications to iodinated contrast material. Cortical scintigraphy is the preferred imaging study for the evaluation of children with acute pyelonephritis, although power Doppler US can be considered as a possible alternative. Recent limited studies using gadolinium-enhanced MRI have been shown to be valuable in the depiction of changes of acute pyelonephritis.

Genitourinary imaging: the past 40 years

During the past 40 years, there has been a dramatic evolution in genitourinary imaging. This evolution has resulted in fundamental changes in the subspecialty. Uroradiology initially focused on radiographic imaging of the urinary tract and was practiced primarily by urologists. After the development of safe intravenous contrast materials, radiologists who focused on the urinary tract and worked closely with urologists forged major advances in urinary tract imaging and intervention. More recently, imaging of the extraurinary genital organs has been added to the subspecialty. Cross-sectional imaging techniques have supplanted radiographic imaging for both urinary and genital imaging. The emergence of the cross-sectional techniques, however, has blurred the traditional organ system-based distinction between gastrointestinal radiology and genitourinary radiology, as both organ systems are imaged simultaneously, and has resulted in a new amalgamation, abdominal radiology, with roots in both specialties. The challenge for the new generation of abdominal radiologists, trained predominantly in cross-sectional techniques, will be to maintain the close interaction with our clinical colleagues that the traditional organ system orientation fostered.

Renal and perirenal abscesses

Our knowledge of the spectrum of renal abscesses has evolved as a result of more sensitive radiologic techniques. The classification of intrarenal abscesses currently includes acute focal bacterial nephritis, acute multifocal bacterial nephritis, renal cortical abscess, renal corticomedullary abscess, and xanthogranulomatous pyelonephritis. The clinical presentation of these entities does not differentiate them, however, and various radiographic studies are helpful in making the diagnosis. The intrarenal abscess is usually treated successfully with antibiotic therapy alone. Antistaphylococcal therapy is indicated for the renal cortical abscess, whereas therapy directed against the common gram-negative uropathogens is indicated for most of the other entities. The perinephric abscess is often an elusive diagnosis, has a more serious prognosis, and is more difficult to treat. Drainage of the abscess and sometimes partial or complete nephrectomy, in addition to antibiotic therapy, are required for resolution.

Delayed CT in acute renal infection

CT scans of the kidneys obtained approximately 3 hours after contrast administration often reveal useful information in patients with renal infections. In this article, we discuss three main features of these delayed scans. Feature 1 shows a nephrogram replacing a variable portion of the low density areas present in the early enhanced phase. The nephrogram can be streaky, band-like, cone or horseshoe-shaped; Feature 2 exhibits a focal staining or a hyperdense rim surrounding microabscesses and macroabscesses; Feature 3, very rare, is characterized by hyperdense areas located far from the lesions detected on early scans. These features make it possible to better define the actual extent of infection and the presence of the edema, improving diagnostic confidence.

Valutazione ecografica e TC di pielonefrite acuta in paziente affetta da rene policistico

Autosomal dominant polycystic kidney disease is a rare nephropathy consisting of multiple cysts that alter almost all the parenchyma of the organ, leading to renal failure. A clinical case with atypical presentation is described.

Focal residual contrast media in the kidney 24 hours after angiography

PURPOSE

To examine the relationship between focal renal cortical retention (FRCR) and contrast-associated nephropathy (CAN).

MATERIAL AND METHODS

We investigated the incidence of both phenomena in 105 patients. CAN was defined as an increase in the creatinine level > 0.3 mg/dl and > 20% on days 1, 3, or 7. We compared predisposing factors for FRCR and CAN. Serum creatinine and blood urea nitrogen (BUN) for renal function were determined on the morning of the day of the angiography. The BUN/creatinine ratio was used as an indicator of the degree of hydration.

RESULTS

FRCR was demonstrated in 17 patients (16%) by delayed CT 24 h after angiography, and CAN was found in 16 patients (15%). No significant relationship between CAN and FRCR was found. We found a correlation between high total volumes of contrast and FRCR. Advanced age, high blood urea nitrogen, high creatinine, and dehydration were risk factors for CAN.

CONCLUSION

Delayed CT showed a higher incidence of injury to the renal parenchyma than previously detected by conventional radiography.

MR findings in diffuse renal parenchymal disease

This study evaluates the MR appearance of the kidney in diffuse renal parenchymal diseases, using precontrast, and immediate and delayed postgadolinium chelate (Gd), spoiled gradient echo (SGE), and pre- and post-Gd, T1-weighted, fat-suppressed spin-echo MR images to determine if characteristic findings exist for various types of renal disease. One hundred twenty-one patients with renal disease underwent MRI. Underlying diagnoses included: (a) glomerular disease (GD), (b) tubulointerstitial disease (TID), (c) microvascular disease (MVD), (d) ischemic nephropathy (INP), (e) obstructive nephropathy (ON), (f) infectious renal disease (IRD), (g) sickle cell disease (SCD), (h) renal cortical necrosis (CN), and (i) renal insufficiency of unknown etiology (UE). MR examinations of 22 patients with normal kidneys (NK) were evaluated as a control group. The presence of corticomedullary differentiation (CMD) demonstrated strong inverse correlation with serum creatinine concentration (SCr) (r = -.568, P < .001). Mean thickness of the renal cortex was 8.4 and 7.8 mm in patients with NK and Gd, respectively. The mean cortical thickness in patients with MVD, TID/Chemo, INP, and ON was 5.2, 5.6, 5.5, and 4.3 mm, respectively, significantly thinner than the renal cortex in the NK and GD groups (P < .01). Irregularity of the renal cortex was more frequent in MVD (60.9%), IRD (62.5%), ON (55.6%), and TID/other (53.8%) than in GD (3.8%) and NK (0%) (P < .01). Diffuse high SI of the entire medulla on delayed postcontrast images was observed in 25 (20.7%) of the patients with renal disease and none of the NK group. Although no pathognomonic features were found, certain findings were observed that may correlate with the etiology of the kidney disease and, therefore, assist in the differential diagnosis of renal parenchymal disease.

Delayed CT findings in acute renal infection

The computed tomography (CT) findings in twelve patients with acute renal infection examined immediately and 3 h after i.v. contrast medium are reported. Three patients also had delayed scans at 6 h. Three main features were observed on the delayed scans: 1 a delayed nephrogram with streaky, wedge shaped or round high density areas. The areas of high density were at the same sites of the inhomogeneous areas of reduced density on the early scans; 2 focal contrast medium staining or a rim of increased density around abscesses; 3 focal areas of increased density at sites distant from the low density areas seen on the early scans. It is postulated that the delayed areas of increased density replace early areas of reduced density caused by ischemia due to vasospasm and/or compressing oedema of the vascular bed or by tubular obstruction. Delayed CT appears to be useful because it improves diagnostic confidence and gives a more exact evaluation of the extent of infection.

Bilateral solid multifocal intrarenal and perirenal lesions: differentiation with ultrasonography, computed tomography and magnetic resonance imaging

The differential diagnosis of bilateral solid multifocal intrarenal and perirenal lesions includes neoplastic, infiltrative, inflammatory, and vascular disorders. In a retrospective study 560 solid lesions were examined with cross-sectional imaging modalities (computed tomography (CT), ultrasonography (US), and magnetic resonance imaging (MRI). The results suggest that focal inflammatory disease can often be recognized because the lesions are poorly defined and may show a rather characteristic peripheral rim enhancement following the administration of intravenous contrast. Angiomyolipomas can be accurately diagnosed with CT, MR and US imaging. Because of their unique histomorphology they show fat-equivalent attenuation values at CT, hyperintense signal on T1 and hypointense signal on T2-weighted MR images, and appear homogeneous and hyperchoic with smooth margins at US. By the radiologic appearance alone renal metastases cannot be distinguished from lymphoma or renal cell carcinoma or adenoma. However, when multiple bilateral solid intrarenal or perirenal lesions are found with synchronous metastatic involvement of other organs or occur in the setting of a known primary tumour, the diagnosis of renal metastases is very likely. In the absence of these additional findings, malignant lymphoma has a higher probability. Infiltration of perinephric fat and thickening of the perinephric fascia may occur in inflammatory disease and lymphoma. CT remains the most suitable imaging technique to screen for these additional perirenal and extrarenal findings because of ready availability and relatively short scanning time as compared to MR imaging.

Computerized tomography in acute pyelonephritis: the clinical correlations

Computerized tomography was performed on 19 patients diagnosed as having uncomplicated acute pyelonephritis. The relationship was investigated among the laboratory findings, presence of flank pain, clinical course and severity of the lesions detected by computerized tomography. In patients febrile for less than 2 weeks healing as assessed by computerized tomography took an average of 76 days. However, in patients with repeated febrile episodes occurring for longer than 2 weeks healing was delayed until an average 232 days after onset. Computerized tomography findings generally correlated well with the erythrocyte sedimentation rate, C-reactive protein level, and presence of pyuria and flank pain. However, in patients with a prolonged course computerized tomography proved to be a more reliable indicator of progress than either the results of laboratory tests or the symptoms. In conclusion, computerized tomography was useful in the diagnosis, assessment of severity and evaluation of healing of acute pyelonephritis.

Migratory lobar nephronia

Lobar nephronia or focal bacterial nephritis is a pre-abscess stage of localized cellulitis and has been shown to represent a focal imaging manifestation of what is frequently a diffuse renal process. To the best of our knowledge, although multi-focal bacterial nephritis has been described, a migratory pattern has not been observed. This report describes a previously healthy 32-year-old woman with pathologically proven lobar nephronia that exhibited a migratory pattern on serial computed tomography (CT) and a prolonged course on antibiotic therapy. Possible etiologies for this unusual course, along with the CT, sonographic and needle biopsy features of this disease are discussed.

The role of scintigraphy in urinary tract infection

There is controversy regarding the role of radiological imaging for urinary tract infection (UTI). The "gold standard" has been the intravenous pyelogram (IVP). Yet, the IVP has a very limited value with only about 25% of children with pyelonephritis demonstrating abnormalities. Ultrasound (US) has recently been advocated as a replacement for the poorly sensitive and poorly specific IVP. However, comparative studies between US and IVP indicate only an equivalent sensitivity and specificity. Cortical scintigraphy with Technetium-99m glucoheptonate (99mTc GH) or 99mTc dimercaptosuccinic acid (99mTc DMSA) has also been advocated as a means of differentiating parenchymal (pyelonephritis) from nonparenchymal (lower UTI) involvement in UTI. The clinical presentation may be misleading especially in the infant and child in whom an elevated temperature, flank pain, shaking chills, or an elevated sedimentation rate are often lacking. The clinician attempts to localize the site of infection for it has a direct bearing upon the therapy. A collecting system infection can often be eradicated with a single oral dose of an appropriate antibiotic, whereas renal parenchymal involvement requires IV therapy for an extended interval. Cortical scintigraphy can localize the site of infection with a high degree of accuracy. Recent studies report a sensitivity of 86% and specificity of 81% of pyelonephritis. This is in contrast to the IVP with a sensitivity of only 24% and US with a sensitivity of only 42%. The scintigraphic appearance of parenchymal infection of the kidney is a spectrum of minimal to gross defects reflecting the degree of histologic involvement that spans from a mild infection to frank abscess. Cortical scintigraphy can be used to monitor the evolution of scarring following infection. Cortical scintigraphy with 99mTc DMSA or 99mTc GH is the method of choice for the initial evaluation of UTI. Not only does it have a very high sensitivity and specificity for differentiating parenchymal from collecting system disease, but it also provides an accurate quantitative measurement of function and in combination with radioiodinated orthoiodohippurate renography and Lasix (furosemide; Abbott Laboratories, North Chicago) diuresis will also differentiate significant obstruction from stasis. The use of radionuclide techniques opens new vistas for the investigation of UTI. Cortical scintigraphy should become the gold standard by which other technologies, therapy, and theoretical considerations of pyelonephritis are measured.

Computerized tomography and acute pyelonephritis in children. A clinical correlation

The clinical records and computerized tomography (CT) scans of 14 patients who presented with pyelonephritis to the Children's Hospital of Buffalo between 1976-1985 have been reviewed. The CT findings were as follows: multifocal pyelonephritis (6), lobar nephronia (6), focal pyelonephritis (2). All patients were treated with intravenous antibiotics, and none was surgically drained. Significant underlying diseases were present in 8 patients: diabetes (6), von Gierke disease (1), hepatorenal syndrome (1). The diabetic children tended to have focal disease. Ten voiding cystourethrograms were performed and only four demonstrated reflux. All children became afebrile within a few days. Lobar nephronia was as clinically responsive as pyelonephritis to antibiotic therapy. Urine cultures were most often positive, although there was 1 patient in each category with negative cultures. Blood cultures were rarely positive in any group. Gram negative organisms predominated. CT scanning in children with clinical acute pyelonephritis reveals three major imaging patterns. While distinct radiographically, they behave in a similar clinical manner. Lobar nephronia does not imply a worse clinical prognosis. Intravenous antibiotic therapy alone was adequate for all patients.

Computed tomography in acute pyelonephritis

The computed tomographic findings in nine female patients with acute pyelonephritis were reviewed. The major impact of CT was the demonstration of renal enlargement, abnormal contour, perirenal inflammatory extension and, on contrast-enhanced scans, abnormal nephrograms and impaired renal function. It was concluded that CT can provide specific information about the nature and extent of the inflammatory process, thus complementing intravenous urography so that appropriate therapy may be selected. Follow-up studies can be helpful in monitoring the progress of a patient.

Demonstration of residual contrast medium in renal parenchyma using computerized tomography

Residual contrast medium in the renal parenchyma was demonstrated by computerized tomography in 11 patients with renal trauma, inflammatory renal disease, infarction and a large renal cyst. The contrast medium (10 to 100 ml.) was administered intravascularly 30 minutes to 48 hours before the computerized tomography scan. In each patient the scan demonstrated residual contrast medium (either initially or after a second scan with additional contrast enhancement) in a variety of parenchymal zones that frequently appear to be normal with other imaging techniques. After a suitable interval for accumulation of residual contrast medium, computerized tomography appears to provide better visualization of the renal parenchyma than conventional modes of examination. Persistent retention of contrast medium in the renal parenchyma is believed to represent cortical damage.

CT evaluation of severe renal inflammatory disease in children

We have performed CT scans on 15 children and 2 young adults with severe renal inflammatory disease. Most children with urinary tract infections do not require such evaluation. We have, however, found CT helpful in defining the nature of renal abnormality and in defining the extent of disease in selected patients who either presented as diagnostic dilemmas or who did not respond initially to proper medical treatment. We therefore use CT scanning as our initial examination in such problem patients.

Computed tomography in the diagnosis of renal pseudotumors

If the initial evaluation of the urinary tract raises the possibility of renal mass, one must decide what study or studies to perform to confirm or deny its presence. Radionuclide imaging has been the study of choice in this situation. Six cases are presented in which computed tomography definitively demonstrated that a suspicious renal mass represented normal renal parenchyma. Comparison with other renal imaging modalities is discussed.

The Role of Sonography and CT in Urosepsis

Both computerized tomography (CT) and sonography are important imaging techniques in patients with major renal infections. Sonography should be performed as the initial screening examination to exclude pyonephrosis or a large renal or perirenal abscess. In patients who continue to have persistent sepsis without adequate explanation by sonography, CT should be performed to characterize the nature of the renal inflammatory process.

Acute lobular nephronia

Acute lobular nephronia is an unusual form of localized renal infection, which has a characteristic computerized tomographic and ultrasonographic appearance, and should be distinguished from abscess or other renal masses. Treatment is nonoperative, consisting of intensive antibiotic therapy.

Perinephric and intrarenal abscesses

Perinephric and intrarenal abscesses remain a significant source of morbidity and mortality as well as a diagnostic dilemma. The history, epidemiology, disease classification, etiology, diagnosis, and treatment are reviewed, with special attention to new diagnostic and treatment modalities.

Acute focal bacterial nephritis: a systematic approach to diagnosis and treatment

Acute focal bacterial nephritis, synonymous with acute lobar nephronia or focal nonliquefactive pyelonephritis, represents a localized area of renal inflammation. Clinically, acute focal bacterial nephritis presents as acute pyelonephritis but is distinguishable by the presence of a focal mass on excretory urography. The further distinction between acute focal bacterial nephritis and other renal masses is aided by the appropriate use of renal sonography and computerized tomography. The clinical and imaging manifestations in 9 patients with acute focal bacterial nephritis are described. Our experience coupled with a review of the literature suggests that a systematic approach to the diagnosis and management of acute focal bacterial nephritis allows for the most efficacious use of the noninvasive imaging modalities.

Renal and perirenal infection: the role of computerized tomography

Predisposing factors, onset of symptoms to diagnosis interval, computerized tomography findings and the impact of computerized tomography on the outcome were studied retrospectively in 24 patients with renal or perirenal infections. The most common predisposing factors were diabetes mellitus and urinary tract calculi. The mean interval from the onset of symptoms to diagnosis was 6.8 days. The most common computerized tomography findings were thickening of Gerota's fascia, renal enlargement, focal decreased renal attenuation, perirenal fluid and focal gas. Four patients died despite early diagnosis and appropriate therapy. Computerized tomography aided in the diagnosis, assessment of the extent of disease, treatment and followup. Computerized tomography is the most direct method to evaluate patients with suspected renal or perirenal infection, although mortality may not be altered significantly.

Computed tomography differentiation of pyelonephritis and renal infarction

Acute renal infarction and acute pyelonephritis can have identical clinical presentations. Most of the computed tomography findings seen in acute renal infarction are similar to those in acute pyelonephritis, except for the characteristic cortical rim sign seen in acute infarction. This finding differentiates these two disorders. This sign may be subtle and not appreciated unless searched for diligently with appropriate computed tomography imaging at varying window settings with particular attention to the subcapsular region.

Squamous cell carcinoma of the renal pelvis: case report emphasizing sonographic and CT appearance

The sonographic and CT appearance of squamous cell carcinoma of the renal pelvis is described. Clinical presentation, pathology, and radiologic diagnosis of this rare urothelial tumor are discussed. The sonographic or CT appearance may suggest this diagnosis preoperatively.

Appearance of renal infarction on computed tomography

We have recently seen three cases of renal infarction secondary to occlusion of renal arteries. Two of these cases had similar clinical presentations and were not diagnosed until computed tomographic (CT) scans were performed (1). The third case was a serendipitous finding. The abnormal findings on CT led to angiography, which confirmed the CT findings in all cases. The CT appearance in those cases was diagnostic, whereas the changes on urography were minimal, if any. We believe that angiography and surgery may be obviated when cases exhibit these characteristic findings on CT.