A simplified method of assessing hemodynamics in technetium-99m sulfur colloid liver imaging

A total of 204 Tc-99m sulfur colloid hemodynamic studies of the liver taken at 5-second intervals were evaluated. The time when the gradually increasing activity in the liver becomes equal to the reducing activity in the heart pool is defined as the relative half clearance time (RHCT) of cardiac activity to the liver. The RHCT was measured in each scan and was correlated with clinical information, liver function tests, and static scan findings. Normal RHCT was established to be in the range of 40 +/- 20 seconds. This study indicates that the RHCT truly reflects the functional status of the hepatic blood flow as well as the phagocytic activity of the Kupffer cells of the liver when cardiac function is normal. A prolonged RHCT may indicate the presence of a parenchymal disease of the liver or cardiac failure with hepatic congestion, or both. The longer the RHCT, the more severe the pathologic condition of the liver, provided that cardiac function is normal.