Dynamic hepatic scintigraphy in the screening of psoriatic patients for methotrexate-induced hepatotoxicity

We report the use of dynamic hepatic scintigraphy in the assessment of the hepatic status of psoriatic patients before and during methotrexate therapy. Eighty-seven paired dynamic scans and percutaneous liver biopsies were performed in 63 patients. The liver biopsies were graded according to Warin et al. with fibrosis of grade 2 or worse being a strong indication for withdrawal of methotrexate. The sensitivity of dynamic hepatic scintigraphy in detecting fibrosis of grade 2 or worse was 83.3% and the specificity was 81.5%. The predictive value of a normal scan for fibrosis of grade 0-1 was high (98.5%) although the predictive value of an abnormal scan for fibrosis of grade 2 or worse was low (25%). Dynamic hepatic scintigraphy may therefore offer a means to reduce the number of liver biopsies necessary in patients receiving methotrexate for psoriasis.