von Hippel-Lindau (VHL) disease is a rare, autosomal dominantly inherited multisystem disorder characterized by development of a variety of benign and malignant tumors. The spectrum of clinical manifestations of the disease is broad and includes retinal and central nervous system hemangioblastomas, endolymphatic sac tumors, renal cysts and tumors, pancreatic cysts and tumors, pheochromocytomas, and epididymal cystadenomas. The most common causes of death in VHL disease patients are renal cell carcinoma and neurologic complications from cerebellar hemangioblastomas. The various manifestations can be demonstrated with different imaging modalities such as ultrasonography, computed tomography, magnetic resonance imaging, and nuclear medicine. Although genetic testing is available, the manifestations of the syndrome are protean; therefore, imaging plays a key role in identification of abnormalities and subsequent follow-up of lesions. It is also used for screening of asymptomatic gene carriers and their long-term surveillance. Screening is important because the lesions in VHL disease are treatable; thus, early detection allows use of more conservative therapy and may enhance the patient's length and quality of life. A multidisciplinary team approach is important in screening for VHL disease.

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Nonrigid registration significantly reduces the effects of movement artifact in subtracted contrast-enhanced breast MRI. This may enable better visualization of small tumors and those within a glandular breast.

Significantly more sites of disease were identified by PET than CT resulting in stage changes and a modification of therapy in 25% of patients. This has important implications not only for current patient management but also for the design of future clinical trials.

ObjectiveTo determine whether to use 18 F-fluorodeoxyglucose positron emission tomography (FDG PET) scans in the preoperative staging of bladder cancer (BC). Patients and MethodsIn all, 233 patients with muscle-invasive BC (MIBC) or high-risk non-MIBC being considered for radical cystectomy (RC) between 2005 and 2011 had FDG-PET and computed tomography (CT) of the chest, abdomen and pelvis to assess for pelvic lymph node (LN) involvement or distant metastases. Sensitivity and specificity for detecting pelvic LN involvement was determined by comparing the results of the scans to the histopathology reports in patients undergoing RC. These parameters for distant metastases were determined from biopsy results or follow-up imaging. In patients who did not undergo RC, follow-up imaging was used to evaluate the sensitivity and specificity. Patients were excluded from analysis if they either had neoadjuvant chemotherapy or had <10 LNs removed at lymphadenectomy. ResultsThe PET scan was able to detect metastatic disease outside of the pelvis with a sensitivity of 54% compared with 41% for the staging CT (N = 207). Both scans had similar specificities of 97% and 98%. There were 13 PET avid lesions not visualised on the corresponding staging CT scans. These proved to be metastatic BC (six patients), a synchronous primary colonic cancer (one), colonic adenomas (one), basal cell tumour of the parotid gland (one) and inflammatory lesions (four). The sensitivity and specificity of the CT scans for pelvic LN involvement was 45% and 98%, respectively (N = 93). Using a combination of the PET and CT scan, the sensitivity for detecting metastatic disease in LNs increased to 69% with a 3% reduction in specificity to 95%. ConclusionsPET when used in conjunction with a standard CT scan provides a small improvement in preoperative staging of BC. However, this advantage is not significant enough to justify the additional cost. Hence we recommend use of dual imaging only in highly selected patients.

Objective To assess the use of unenhanced spiral computed tomography (CT) as the primary investigation of choice for suspected acute renal colic in clinical urological practice. Patients and Methods Between 1 August 1997 and 31July 1998, all patients attending a hospital accident and emergency department with acute loin pain suggestive of renal colic underwent a physical examination, urine analysis, plain abdominal radiography (if clinically indicated) and unenhanced spiral CT. The effective radiation dose and ®nancial cost of unenhanced spiral CT and standard three-®lm emergency intravenous urography (IVU) were calculated. Results In all, 116 patients were assessed, 63 of whom had calculi and related secondary phenomena of obstruction identi®ed on unenhanced spiral CT. There were two false-positive and one false-negative result. An alternative urinary tract diagnosis was made in four patients, including two with renal cell carcinoma and one ureteric transitional cell carcinoma. Causes other than in the urinary tract were diagnosed in three patients, i.e. two with ovarian cyst and one with sigmoid diverticulitis. The effective radiation dose of unenhanced spiral CT was 4.7 mSv and that for three®lm IVU was 1.5 mSv. The costs of both IVU and unenhanced spiral CT were identical. Conclusions Unenhanced spiral CT allows a rapid, contrast-medium-free, anatomically accurate diagnosis of urinary tract calculi and in the present series had a sensitivity of 98% and a speci®city of 97%. CT provided an alternative diagnosis in 6% of patients. These advantages must be weighed against the threefold greater radiation dose of unenhanced spiral CT than with three-®lm IVU, and in practice the requirement for a radiologist to interpret routine axial scans.

In vitro, i.v. contrast-enhanced MDCT is more sensitive than first-order aortic branch-selective DSA in detecting active hemorrhage unless the catheter position is highly superselective and is close to the bleeding artery. These results suggest that MDCT can be used as the initial imaging technique in the diagnosis of active hemorrhage if the clinical condition of the patient allows.