Lung Perfusion Imaging with Technetium-99m Macroaggregated Albumin should be Combined with Contrast-enhanced Echocardiography for the Diagnosis of Hepatopulmonary Syndrome

摘要

Dear Editor, We have read with great interest the recent article by Alipour et al. ( 1 ) regarding the diagnosis of hepatopulmonary syndrome (HPS) with right-to-left (R-L) shunt in cirrhotic patients using the technetium-99m macroaggregated albumin (Tc-99m MAA) lung perfusion scintigraphy (LPS). The authors have found that LPS was more sensitive than contrast-enhanced echocardiography (CEE) for detecting intrapulmonary vascular dilatations (IPVDs) and concluded that Tc-99m MAA LPS can be used complementarily with other diagnostic methods in the assessment of HPS ( 1 ). However, we have some concerns regarding this work. The authors appraised the shunt fraction (SF) by using the formula SF=(geometric mean of brain counts)/(geometric mean of brain counts+geometric mean of lung counts), without dividing the geometric mean of brain counts by 0.13, although the brain is presumed to receive 13% of the cardiac output ( 2 ). Moreover, both LPS and CEE procedures were not described in sufficient detail.