Dynamic 99Tcm-HIDA SPET: non-invasive measuring of intrahepatic bile flow. Description of the method and a study in primary sclerosing cholangitis

In this study dynamic 99 Tc m -HIDA single photon emission tomography (SPET) was performed in patients with primary sclerosing cholangitis and normal test subjects. The method offers the possibility of functional analysis of individual liver segments. After injection of 120 MBq of 99 Tc m -HIDA, 12 consecutive SPET examinations were performed at 6-min intervals. The segmental borders of liver segments as seen on computed tomography or magnetic resonance examinations were superimposed on the scintigraphic images allowing placement of regions of interest (ROIs) in specific liver segments. Sampling from the same ROIs in consecutive SPET images enabled creation of time-activity curves for individual liver segments. A range of normal values was created by quantitative analysis of normal volunteer studies. Results of the studies in patients correlated well with cholangiographic extent of disease, liver function tests and histological stage. The technique may have particular value in diseases that affect the liver in a non-homogenous or segmental fashion. Giving an indication of bile clearance from individual liver segments, it can quantify the functional importance of radiologically detected strictures. Percutaneous liver biopsy can be directed to the worst affected parts of the liver, making biopsy more representative. Sequential studies may allow monitoring of disease progression, aiding in selection and timing of therapeutic procedures.