Poorly differentiated small cell carcinomas and malignant melanomas are among the rarest of primary colorectal malignancies. Although very aggressive and lethal, small cell carcinomas and the amelanotic variety of malignant melanomas have similar radiological features to adenocarcinomas. We present two different cases with these unusual tumours, with special emphasis on their dynamic contrast-e...

Introduction: Dynamic contrast-enhanced (DCE-) MRI has become a valuable tool in the assessment of tumors and in the evaluation of the effects of treatment. Kinetic modeling with two or three (including tumor vascular component vp) compartments is commonly used to measure the parameter K, a first order rate constant that describes tumor perfusion and vascular permeability. In its calculation, t...

This is a case study of a 34-year-old woman who was admitted to hospital with a history of severe orthostatic headache. She was diagnosed as having spontaneous intracranial hypotension (SIH) by undetectable cerebrospinal fluid (CSF) pressure at lumbar puncture, and with evidence of diffuse dural enhancement of the brain detected by magnetic resonance imaging (MRI). However, the contrast-enhance...