Abdominal air: the radiologist's enemy and friend

Two cases are presented which illustrate the radiological drawbacks and advantages of air when it is present either around or within an organ of clinical interest. The physical principles underlying this anomaly are briefly discussed, particularly in relation to plain film radiology and ultrasonic imaging. The importance of recognising this phenomenon and the diagnostic difficulties which may arise stressed

Ultrasonic demonstration of portal vein occlusion

The ultrasonic detection of pre-sinusoidal portal vein obstruction is described in a patient with clinical features of alcoholic liver disease. The case illustrates the advantages of ultrasound in the evaluation of the portal circulation, including unusual radiological observations of the portal circulation