A case of mass-forming splenic tuberculosis: MRI findings with emphasis of diffusion-weighted imaging characteristics

Diffusion-weighted magnetic resonance imaging of abdominal tuberculosis: a new take on an old disease

Abdominal tuberculosis is a major cause of mortality and morbidity in developing countries also re-emerging in western world due to the AIDS epidemic and population migration. Large proportion of the patients are young and hence radiation exposure is of concern. In addition, in some patients, contrast may be contraindicated or repeat studies may be required, where MR especially DWI may be useful. The aim of the study is to describe MRI features in abdominal tuberculosis including DWI in the involved bowel, lymphadenopathy, omental, and peritoneal thickening. Nodes being especially easy to appreciate on DWI, thus DWI in conjunction with routine noncontrast MR sequence can be useful technique to identify abdominal tubercular lesions in patients with contraindication to contrast.

Contrast-Enhanced Ultrasound Imaging Features of Focal Splenic Tuberculosis

Background

The aim of this study was to characterize the contrast-enhanced ultrasound imaging features of focal splenic tuberculosis.

Material/Methods

We retrospectively analyzed the conventional ultrasound (US) and contrast-enhanced ultrasound (CEUS) imaging features of 22 patients with splenic TB confirmed by surgical histopathology or biopsy.

Results

Conventional US demonstrated that 15 of the 22 patients had a single lesion, while 7 had multiple lesions. The maximum diameter of the lesions ranged from 1.0 to 3.7 cm. Of the 22, 17 were detected with hypoecho and 5 were detected with complex echo by conventional US. Seven (7/22) were detected with blood flow signals by color Doppler flow image (CDFI). CUES demonstrated that 18 cases (81.8%, 18/22) began to enhance in the arterial phase, mostly followed by slow wash-out in the intermediate or late parenchymal phase, and 4 (18.2%, 4/22) presented with non-enhancement during all phases. The enhancement patterns were categorized into 4 types: Type I, homogeneous enhancement (2/22); Type II, rim-like enhancement (12/22); Type III, septation-like enhancement (4/22); and Type IV, non-enhancement (4/22).

Conclusions

CEUS showed that splenic TB lesions were enhanced in the arterial phase, followed by slow washed out or persistent enhancement in the intermediate and late parenchymal phases. The rim- or septation-like enhancement may be helpful for diagnosing splenic TB. The splenic lesions presenting round hypoecho by conventional US and complete non-enhancement by CEUS are highly suspicious of splenic TB.

Splenic Involvement in Disseminated Mycobacterium avium-intracellulare Infection: Magnetic Resonance Imaging Findings

We report the imaging findings of a patient with disseminated Mycobacterium avium-intracellulare complex presenting with multiple splenic lesions incompletely characterized on computed tomography in whom magnetic resonance imaging helped narrow the differential diagnosis. We discuss the magnetic resonance imaging findings suggesting the diagnosis, including the presence of focal susceptibility artifact within the lesions (ie, signal drop on T1 in-phase imaging), marked hypointensity on diffusion-weighted imaging, and faint progressive peripheral enhancement after contrast administration. We provide pathologic correlation to explain these imaging characteristics and a review of the literature of imaging characteristics in splenic involvement of M. avium-intracellulare complex infection.

Diffusion-weighted magnetic resonance imaging for non-neoplastic conditions in the hepatobiliary and pancreatic regions: pearls and potential pitfalls in imaging interpretation

Potentially, diffusion-weighted magnetic resonance imaging (DWI) can assess the functional information on concerning the status of tissue cellularity, because increased cellularity is associated with impeded diffusion. DWI in the hepatobiliary and pancreatic regions has demonstrated the usefulness to detect malignant lesions and differentiate them from benign lesions. However, it has been shown more recently that there is some overlap in ADC values for benign and malignant neoplasms. Moreover, some non-neoplastic lesions in the hepatobiliary and pancreatic regions exhibit restricted diffusion on DWI, because of pus, inflammation, or high cellularity. Focal eosinophilic liver disease, hepatic inflammatory myofibroblastic tumor, granulomatous liver disease, acute cholecystitis, xanthogranulomatous cholecystitis, focal pancreatitis, or autoimmune pancreatitis frequently exhibit restricted diffusion on DWI, which may be confused with malignancy in the hepatobiliary and pancreatic regions. Thus, DWI should not be interpreted in isolation, but in conjunction with other conventional images, to avoid the diagnostic pitfalls of DWI. Nevertheless, the presence of diffusion restriction in the non-neoplastic lesions sometimes provides additional information regarding the diagnosis, in problematic patients where conventional images have yielded equivocal findings. DWI may help differentiate hepatic abscess from malignant necrotic tumors, gallbladder empyema from dense bile or sludge in the gallbladder, and pylephlebitis from bland thrombosis in the portal vein. Therefore, knowledge of DWI findings to conventional imaging findings of diffusion-restricted non-neoplastic conditions in the hepatobiliary and pancreatic regions helps establishing a correct diagnosis.

Unusual location of tuberculosis in the course of tumor necrosis factor α inhibitor therapy

Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis complex mycobacteria. Extrapulmonary tuberculosis usually develops more than two years after infection or many years later. Factors favoring onset of the disease are malnutrition, older age, renal failure, diabetes, cancer, immunosuppression and biological treatment, e.g. tumor necrosis factor α (TNF-α) inhibitors. The paper presents a case of a 56-year-old patient with ankylosing spondylitis treated with infliximab, diagnosed with tuberculosis of the spleen. The unusual location and uncharacteristic symptoms created a lot of diagnostic difficulties, particularly as during qualification for biological treatment tests are performed to exclude infection with Mycobacterium tuberculosis. Pharmacological treatment of tuberculosis is typical, but in the case of tuberculosis of the spleen, splenectomy also is a method of treatment. The decision was made to implement pharmacological treatment, which proved to be effective, so the patient avoided surgery.

Nononcologic applications of diffusion-weighted imaging in the gastrointestinal system

OBJECTIVE

The purpose of this article is to review infectious, inflammatory, and auto-immune-mediated processes in the gastrointestinal system where diffusion-weighted imaging can be helpful as well as pitfalls associated with its use.

CONCLUSION

Diffusion-weighted imaging has become an important and widely used tool in abdominal and pelvic MRI, but it has been used primarily for oncologic applications. As more body MRI protocols are routinely including diffusion-weighted imaging, this sequence can be useful in evaluating an increasing number of nononcologic processes.

Tuberculosis--the great mimicker

Tuberculosis is an immense health problem in the developing world, and it remains a health care challenge in the developed world. It can affect virtually any organ system in the body. Diagnosis of tuberculosis is often difficult. Many patients with tuberculosis present with nonspecific symptoms, negative purified protein derivative skin test result, and negative findings on culture specimens. Cross-sectional imaging with ultrasound, multidetector computed tomography, and magnetic resonance imaging plays an important role in the diagnosis of tuberculosis. 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.

The Mysterious Organ. Spectrum of Focal Lesions within the Splenic Parenchyma: Cross-Sectional Imaging with Emphasis on Magnetic Resonance Imaging

Incidental splenic lesions are frequently encountered at imaging performed for unrelated causes. Splenic cysts, hemangiomas, and lymphomatous involvement are the most frequently encountered entities. Computed tomography and sonography are commonly used for initial evaluation with magnetic resonance imaging reserved as a useful problem-solving tool for characterizing atypical and uncommon lesions. The value of magnetic resonance imaging lies in classifying these lesions as either benign or malignant by virtue of their signal-intensity characteristics on T1- and T2-weighted imaging and optimal depiction of internal hemorrhage. Dynamic contrast-enhanced sequences may improve the evaluation of focal splenic lesions and allow characterization of cysts, smaller hemangiomas, and hamartomas. Any atypical or unexplained imaging feature related to an incidental splenic lesion requires additional evaluation and/or follow-up. Occasionally, biopsy or splenectomy may be required for definitive assessment given that some of tumours may demonstrate uncertain biologic behavior.

Imaging of tuberculosis of the abdominal viscera: beyond the intestines

There is an increasing incidence of both intra- and extra-thoracic manifestations of tuberculosis, in part due to the AIDS epidemic. Isolated tubercular involvement of the solid abdominal viscera is relatively unusual. Cross-sectional imaging with ultrasound, multidetector computed tomography (CT), and magnetic resonance imaging (MRI) plays an important role in the diagnosis and post treatment follow-up of tuberculosis. Specific imaging features of tuberculosis are frequently related to caseous necrosis, which is the hallmark of this disease. However, depending on the type of solid organ involvement, tubercular lesions can mimic a variety of neoplastic and nonneoplastic conditions. Often, cross-sectional imaging alone is insufficient in reaching a conclusive diagnosis, and image-guided tissue sampling is needed. In this article, we review the pathology and cross-sectional imaging features of tubercular involvement of solid abdominopelvic organs with a special emphasis on appropriate differential diagnoses.

MRI findings of granulomatous prostatitis developing after intravesical Bacillus Calmette-Guérin therapy

AIM

To evaluate magnetic resonance imaging (MRI) findings of granulomatous prostatitis (GP) developing after intravesical Bacillus Calmette-Guérin (BCG) therapy.

MATERIALS AND METHODS

Ten patients with pathologically proven GP underwent prostatic MRI. Lesion shape and signal intensity (SI) were evaluated on T2-weighted (T2WI), T1WI, and diffusion-weighted imaging (DWI).

RESULTS

Polygonal nodular lesions with notches, diffuse lesions, and cystic lesions with mural nodules were seen in two, six, and one patients, respectively. The remaining patient had a diffuse and cystic lesion. All diffuse lesions showed higher SI than muscle on T1WI and higher SI than the normal peripheral zone (PZ) on DWI. On T2WI, six of seven diffuse lesions showed a slightly lower SI than bone marrow and the remaining one lesion was iso-intense. All nodular lesions showed a low SI similar to muscle on T2WI and were iso-intense to muscle on T1WI. On DWI, two each of the four nodular lesions showed slightly lower SI and slightly higher SI than the normal PZ, respectively. All contents within the cyst and mural nodules showed markedly high and low SI on T2WI, respectively. On DWI, all fluids within cysts showed markedly high SI. One each of the mural nodules showed slightly higher SI and slightly lower SI than the normal PZ on DWI.

CONCLUSION

Three main MRI patterns of GP were identified: diffuse, nodular, and cystic with mural nodule; among them, the diffuse type was the most common. Cystic lesions with mural nodules could accompany the lesion.

[Symptomatic hypercalcemia presenting as a case of isolated splenic tuberculosis]

BACKGROUND AND OBJECTIVE

To describe an unusual clinical presentation as isolated splenic tuberculosis.

PATIENT AND METHODS

We report a case of isolated splenic tuberculosis, a rare form of extrapulmonary tuberculosis in an immunocompetent patient, and, as a peculiarity, debuts in the form of symptomatic hypercalcemia.

RESULTS

We deeply report the clinical case and the procedures performed to exclude other diseases. We emphasize the usefulness of fine needle aspiration of the spleen to obtain microbiological samples, and the use of specific polymerase chain reaction for mycobacterias to establish the definitive diagnosis of this entity. In agreement with other authors, we chose initial medical treatment with antituberculous drugs, reserving surgery for refractory cases or in case of spontaneous splenic rupture.

CONCLUSION

Hypercalcemia can be a presentation of granulomatous diseases. The isolated involvement of the spleen by mycobacterias is a rare form of extrapulmonary tuberculosis and more so in immunocompetent patients.

Clinicopathologic significance of high signal intensity on diffusion-weighted MR imaging in the ureter, urethra, prostate and bone of patients with bladder cancer

RATIONALE AND OBJECTIVES

The aim of this study was to determine the clinicopathologic significance of high-intensity areas in the ureter, urethra, prostate, and bone incidentally found on diffusion-weighted magnetic resonance imaging (DWI) for the staging of bladder cancer.

MATERIALS AND METHODS

Axial and sagittal DWI and T2-weighted imaging of the pelvis were evaluated in 157 patients with bladder cancer. Two observers assessed T2-weighted imaging with DWI independently. The observers pointed out 67 areas showing abnormal high signal intensity on DWI in the ureter (n = 17), urethra (n = 8), prostate (n = 20), and bone (n = 22). Of the 67 high-intensity areas, 33 lesions were confirmed histopathologically (ureter, n = 10; urethra, n = 7; prostate, n = 16), and 22 bone lesions were diagnosed using T1-weighted imaging and follow-up computed tomography. Thus, 55 lesions were evaluable for correlation with DWI findings.

RESULTS

Of the 55 high-intensity areas, 28 (53%) were synchronous or metastatic urothelial cancer or invasion of urothelial cancer. The remaining 27 (47%) were a ureteral clot in one, a ureteral stone granuloma in one, prostatic cancer in six, granulomatous prostatitis in three, and normal red bone marrow in 16.

CONCLUSIONS

DWI is useful to comprehend the extent of bladder cancer and to detect incidentally coexisting diseases. Other imaging, endoscopic, and clinical findings would be useful to reduce false positivity.