Magnetic resonance (MR) imaging is often used in the detection and staging of large pelvic masses. Many large masses in the female pelvis arise from the reproductive organs (eg, uterus, cervix, ovaries, fallopian tubes). In addition, these masses may arise from the gastrointestinal system, urinary system, adjacent soft tissues, peritoneum, or retroperitoneum or from metastases. The majority of large masses in the female pelvis represent such commonly encountered entities as uterine fibroid tumor, dermoid tumor, ovarian cyst, and ovarian cancer. However, uncommon pelvic masses such as mesothelioma, adenocarcinoma, carcinosarcoma, leiomyosarcoma, and desmoid tumor may also be seen. Thus, the differential diagnosis for female pelvic masses is extensive. However, the site of origin, MR imaging characteristics, and clinical history may all help narrow the differential diagnosis. Although with large tumors it may not always be possible to determine the site of origin or distinguish between various tumors at radiology, familiarity with the clinicopathologic and MR imaging features of common and uncommon pelvic masses is important for diagnosis and treatment.

Positron emission tomography (PET) with 2-[fluorine-18] fluoro-2-deoxy-d-glucose (FDG) may play an important role in the evaluation and management of malignant lymphoma. FDG uptake is predictive of therapeutic response during the course of treatment. After completion of chemotherapy, residual abnormalities representing either residual tumor or necrotic or fibrotic tissue are not uncommon, and FDG PET may be more accurate than computed tomography (CT) or magnetic resonance imaging in assessing residual disease and identifying patients who require more intense treatment. However, posttreatment FDG PET does not help exclude the presence of minimal residual disease, which may lead to disease relapse. Furthermore, FDG is not a tumor-specific substance, and increased accumulation may be seen in a variety of benign entities and scenarios (eg, infection, drug toxicity, granulocyte colony-stimulating factor therapy, radiation therapy, physiologic activity, postoperative or postbiopsy changes, fracture, degenerative change, injection leakage), which may yield false-positive findings. Nevertheless, recognition of these entities and correlation of FDG PET findings with clinical and other radiologic findings-especially those at combined PET and CT or PET-CT fusion imaging-allows improved diagnostic accuracy. If the interpretation of positive findings is exceptionally difficult, short-term follow-up may be helpful.

Twenty-five patients had a high-grade lymphoma and eight had a low-grade lymphoma. The stomach was the most common site of the involvement (20 patients). In high-grade lymphoma, PET showed focal nodular or diffuse hypermetabolic activity. The average SUV(max)+/-SD was 11.58+/-5.83. After the therapy, the patients whose biopsies showed no evidence of lymphoma had a lower uptake without focal lesions. The SUV(max)+/-SD decreased from 11.58+/-5.83 to 2.21+/-0.78. In patients whose post-treatment biopsies showed lymphoma, the SUV(max)+/-SD was 9.42+/-6.27. Low-grade follicular lymphomas of the colon and stomach showed diffuse hypermetabolic activity in the bowel wall (SUV(max) 8.2 and 10.3, respectively). The SUV(max) was 2.02-3.8 (mean 3.02) in the stomach lesions of patients with MALT lymphoma. ONCLUSION: (18)F-FDG PET contributes to the diagnosis of high-grade gastrointestinal non-Hodgkin's lymphoma, even when there is the normal background FDG activity. Furthermore, the SUV plays a role in evaluating treatment response. Low-grade NHL demonstrates FDG uptake but at a lesser intensity than seen in high-grade NHL.

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Common lower urinary tract fistulas can present as uroenteric fistulas, urogenital fistulas and urocutaneous fistulas. They usually occur as sequel after pelvic surgery, obstetric complications following childbirth and gynecologic procedures. In patients with underlying neoplasm, fistulas may occur from primary or recurrent tumors and as a consequence of pelvic irradiation. Infectious process, trauma and congenital abnormalities can also cause lower urinary tract fistulas. Clinical presentation depends on the location and type of fistula. Radiographic imaging can give diagnosis and demonstrate associated complications of fistulas. Being familiar with clinical signs and symptoms as well as choosing the appropriate imaging modality and technique are important. This article reviews common types of lower urinary tract fistulas correlated with their cause, clinical presentation and imaging modalities for diagnosis.

Pretreatment radiographic features of HIV-related TB had a significantly higher prevalence of the miliary pattern and lower prevalence of reticular infiltration, cavitation, and mass-like lesions. HIV-related TB and the miliary pattern seen by pretreatment radiography were significantly associated with normal chest radiographs during the posttreatment period.

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