Fig. 3

Technetium-labeled (Tc-99 m) macroaggregated albumin (MAA) lung perfusion scan, evaluates how well blood circulates within the lungs. It showed marked decrease in perfusion to the left compared to the right lung (4.3 % vs. 95.7 %) prior to operation (b), while both lung perfusions were almost similar (54 % vs 46 %) 6 years prior (a). This is because the right lung was protected by the RPA band, while the left lung received the majority of cardiac output, exposing it to significant increased flow and pressure. As a result, there was increased pulmonary vascular resistance and poorer delivery of the radioactive tracer to the left lung [17, 18]. In this case, pulmonary vascular remodelling was shown to be partially reversible even operated late. Twenty-one months post operation, a repeat lung perfusion scan showed improved left lung perfusion to 20.2 % (c)