There has been a lot of interest in arrythmogenic right ventricular dysplasia and I expect you know how to diagnose it on CT but I thought it would help for me to show you this case. She was a young woman in her 20s and arrived moribund with a working diagnosis of massive pulmonary embolus. Hence the CT. She died soon after and her pathology specimen is on the left. It helps to realise that the fatty degeneration of the RV myocardium starts in the wall proper and affects the trabecula last. Also, it begins in the lateral free wall. So, the CT appearances of the apical half of the right ventricle are minimally affected,as the apex is nearly all trabeculation. Nearer the base, in the area circled, it is much more obvious that there is no normal myocardium between the fat and the opacified ventricular cavity.