"Hot spot" on hepatic scintigraphy and radionuclide venacavography.

Seven patients showing a localized area of increased uptake (hot spot) on 99mTc sulfur colloid liver scans are described. Four also had dynamic studies. In five patients the hot spot was associated with superior vena caval obstruction, in one it was associated with inferior vena caval obstruction, and in one with a hepatoma. Although a hot spot on static liver images usually indicates superior vena caval obstruction, the addition of radionuclide venacavography is recommended to confirm the diagnosis. A hot spot in the liver area in a radionuclide venogram of the lower limbs suggests inferior vena caval obstruction with collaterals via the liver.