Index of convexity: A novel liver function index using Tc-GSA scintigraphy

Figure 1 Representative time activity curves of a liver with good function (top) and poor function (bottom). ΔABC was drawn over the liver curve between the data points at 3 min and 27 min. D, E: The midpoints of lines AB and BC, respectively; F: The intersection of arc AB and line DE. The ratio of the length of DF to the length of DE is defined as index of convexity (IOC). High IOC values indicate good liver function.

Figure 2 Scatter diagram of index of convexity and indocyanine green retention rate at 15 min. A strong correlation between the 2 parameters is observed (r = -0.761 ). IOC: Index of convexity; ICG R15: Indocyanine green retention rate at 15 min.

Figure 3 Receiver operating characteristic curves of index of convexity, clearance index, and receptor index for the diagnosis of cirrhosis. IOC: Index of convexity; HH15: Clearance index; LHL15: Receptor index.