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Magnetic resonance cholangiopancreatography (MRCP) is a non-invasive imaging method for examining the biliary and pancreatic ducts. The technique uses heavily T2-weighted imaging, which produces high signal from bile and other static fluids by virtue of their long T2 time, while suppressing background signal. Fast scanning techniques, particularly half-Fourier fast spin-echo techniques, are continuing to improve image resolution and allow scans within short breath-holds, reducing the effects of respiratory movement. The MRCP method has reached a level of resolution and reliability where it may well largely replace diagnostic endoscopic retrograde cholangiopancreatography (ERCP) in the near future. A review of MRCP techniques and imaging findings is presented with emphasis on half-Fourier imaging, with reference to potential clinical indications and limitations. Use of MRCP shows a high sensitivity and specificity for detection of biliary dilatation, calculi, strictures and anatomical variants. Experience with MR imaging of the pancreatic duct is less extensively described in the literature, but pancreatic duct dilatation, calculi and anatomy can now be reliably detected. However, as experience with MRCP increases, some sources of errors and limitations are becoming apparent, with image artefacts, and gas, blood or sludge within ducts potentially mimicking stones or strictures.

SUMMARY Expandable metallic stents have been used with considerable success for the palliation of malignant vena caval obstruction. The role of stenting in vena caval obstruction of benign aetiology is less well defined. A review of 11 patients stented for vena caval obstruction and a review of recent series in the literature is presented. Of the 11 patients, seven patients had involvement of the superior vena cava (SVC), and four patients had inferior vena caval (IVC) obstruction. Seven cases had malignant vena caval obstruction, with a benign aetiology (SVC n = 3; IVC n= 1) in the other four cases. All seven patients treated with SVC stents experienced complete resolution or significant improvement in symptoms with no recurrence over the duration of available follow-up, over an average of 4.3 months (range: 1 week-12 months). Only one of four IVC lesions stented resulted in a good clinical response. All four patients with vena caval obstruction of benign aetiology had a good outcome. One patient experienced a small pulmonary embolus following SVC stent insertion without further sequelae. No other serious complications were encountered. Stenting can provide prompt relief of vena caval obstruction with low morbidity, and high patency rates in both benign and malignant vena caval lesions.

Intracranial epidermoids can closely mimic cerebrospinal fluid (CSF) on MRI and CT. Therefore epidermoids can be difficult to detect, or distinguish from CSF. Three cases of intracranial epidermoid are presented, one of which closely mimicked an arachnoid cyst on CT and routine MRI sequences. Diffusion-weighted magnetic resonance imaging (DWI) was performed. All three epidermoids demonstrated marked restriction of diffusion relative to CSF, clearly defining the extent of each lesion, and allowing differentiation from an arachnoid cyst or an enlarged CSF space.