Paradoxical Splenic Signal Loss on Chemical-Shift MRI in Acute Toxic Hepatitis After Occupational Petroleum Sludge Exposure: A Case Series

Background: Acute toxic hepatitis after work-related exposure to petroleum products is rare. Its imaging features are not well known. Methods: Seven men aged 18–35 years cleaned the same petroleum storage tank for two days. Symptoms began about 5 days later. Ultrasound and CT were done at admission. Non-contrast 3 T MRI with in-phase and opposed-phase imaging was done about 10 days after exposure. The splenic signal intensity ratio (SIR, in-phase/opposed-phase) was compared with that of 15 age- and sex-matched healthy controls. Results: At admission, median ALT was 481 U/L, median AST 227 U/L, and median total bilirubin 6.1 mg/dL. The injury was hepatocellular by R ratio in the six patients with raised ALT. Periportal edema was seen in 6 of 7 patients. No patient had biliary obstruction or vascular thrombosis. Notably, all seven patients demonstrated paradoxical splenic signal loss on in-phase compared with opposed-phase MRI, with a median splenic signal intensity ratio (SIR) of 0.77 (IQR, 0.74–0.81; range, 0.70–0.87). Splenic SIR was lower in patients than in healthy controls (median 0.77 vs. 1.05; p < 0.001). All patients recovered with supportive care. Conclusions: In this single exposure cluster, the spleen lost signal on in-phase images. This pattern is usually linked to iron or other T2* effects. The finding is preliminary. It needs confirmation with iron measurement, hemolysis tests, and follow-up MRI.