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A 64-year-old woman with a history of cirrhosis and progressive difficulty breathing underwent pulmonary ventilation/perfusion SPECT to evaluate possible pulmonary embolism. The images demonstrated multiple mismatched ventilation/perfusion defects in both lungs, suggesting pulmonary embolism. However, there was also Tc-MAA radioactivity in the brain and bilateral kidney, with a right-to-left shunting rate of 8.8%. In addition, CT pulmonary angiography did not demonstrate embolus. The findings indicated that perfusion defects were caused by hepatopulmonary syndrome.

Hepatopulmonary syndrome, also known as hepatorenal syndrome, is a triad of liver disease, impaired oxygenation, and intrapulmonary vascular abnormalities. Forty-seven percent of patients with end-stage liver disease may have hepatopulmonary syndrome, an independent predictor of poor prognosis. Gross dilatation of pulmonary precapillary and capillary vessels, as well as an absolute increase in the number of dilated vessels, is the classic pathological description. We report a young man with cirrhosis demonstrating extrapulmonary shunting of 99mTc-MAA to kidneys with extensive peripheral arteriovenous (cutaneous) vasodilation, which we prefer to name as the "mosaic sign" in the absence of spider nevi or erythema.

We present the right to left shunt study findings of a 50-year-old male patient with hepatitis C cirrhosis, who complained of worsening dyspnea on exertion. Follow-up images showed resolution of hepatopulmonary syndrome following methadone withdrawal although there had been no improvement in his liver disease. This was unusual and may have been due to the effect of opiate receptors on nitric oxide signaling in the pulmonary vasculature.

Hepatomegaly is a common manifestation in Gaucher disease. In some patients with the disease, hepatic fibrosis and portal hypertension are observed. A patient with Gaucher disease with the hepatopulmonary syndrome associated with severe cyanosis and hypoxemia was examined for intrapulmonary right-to-left shunt using Tc-99m MAA. Quantitative evaluation revealed an approximately 50% right to left shunt as indicated by Tc-99m MAA activity in the lungs and systemic organs.