Search

Although contrast cholangiography has a greater accuracy than sonography in determining the precise nature of extrahepatic biliary obstruction, it is not without risk. High-resolution real-time sonography is frequently adequate to evaluate the extrahepatic biliary system in multiple planes without known risk to the patient. In a one-year period the authors prospectively observed eight instances of distal biliary obstruction with abrupt termination of the common bile duct, and all were associated with malignant obstruction. There was no instance of abrupt ductal termination secondary to benign disease in this series. Malignancy should be suspected when careful sonograms along the longitudinal axis of an obstructed distal common bile duct reveal an abrupt termination.

Volumes and surface areas of 45 kidneys were determined ultrasonographically in vivo before autopsy and in a water bath phantom after autopsy by means of both the ellipsoid and the stepped section methods. Comparison of results revealed that renal volume may be determined by the simplest method, the ellipsoid method, with sufficient accuracy for clinical use. Results also revealed that renal mass expressed in grams may be directly obtained from renal volume expressed in milliliters, but mass in grams was found to correlate better with renal surface area than with renal volume. A formula relating renal mass to both volume and surface area was developed from regression analysis of the data and was found to provide a more precise estimate of renal mass than does mass computed from either volume or surface area alone.

A mathematical model is presented for the dynamics of a bolus of technetium-99m-labeled red blood cells through the left ventricle. It is used to correct for attenuation the count rate observed over the left ventricle during a conventional gated blood-pool study. The left-ventricular volumes are calculated from the corrected count rates and expressed as a percentage of total blood volume, or in absolute terms if a blood sample is obtained. The procedure is applied to a number of patients with nonvalvular cardiac disease. Cardiac volumes determined by the method are found to correlate well (r = 0.98) with those determined by contrast left ventriculography. The method is simple, requires no special equipment, and can be applied with existing computer software.