Analysis of diffuse parenchymal liver disease by liver scintigrams: Differential diagnosis using fuzzy inference and genetic algorithm in nuclear medicine

In nuclear medicine, diagnosis of diffuse parenchymal liver disease such as chronic hepatitis (CH) or liver cirrhosis (LC) is evaluated by size and di stortion of the liver, distribution of radioactive tracer in the liver, siz e and activities of the tracer in the spleen, the degree of visualization o f the bone marrow, etc, using colloid liver scintigraphy. It is not difficu lt to read a scintigram for a typical pattern; however in some cases it is difficult to distinguish between normal and CH or CH and LC visually. There fore, we tried to use fuzzy inferences to perform differential diagnosis. U sing fuzzy inference, differential diagnosis of LC could be performed up to 100%, but those of CH and Severe fibrosis (SF) could not be performed suff iciently. Therefore genetic algorithm was tried to determine the fuzzy rule s. By combining genetic algorithm and fuzzy inference, CH, SF, and LC could be differentiated to the degree 70%, 60%, and 100%, respectively.