Evaluation of pulmonary vein variations in the middle pulmonary lobe with 64-slice multidetector computed tomography

Purpose: To evaluate the multi detector computed tomographic (CT) depiction of middle lobe vein variation of the right pulmonary vein and create a diagram for cardiologist and cardiovascular surgeons. Materials and Methods: According to hospital records, between January 2009 and April 2010, 314 consecutive patients underwent pulmonary CT angiography (CTPA) and coronary CT angiography. The CT films from these patients were retrospectively analyzed. Results: Under normal conditions, the middle pulmonary vein (MPV) drains into the left atrium either by the "direct" or "indirect" route. Direct (37 patients, 11.8%) drainage means that the MPV does not drain into the upper or lower pulmonary veins but instead drains directly into the right pulmonary vein system. In contrast, indirect (276 patients, 87.9%) drainage occurs when the MPV drains into the upper or lower pulmonary veins. In this study, 12 different variations in drainage patterns were found. Conclusion: Increasing the number of patients may have led to the identification of additional variants. However, clinically important variations are rarely seen. Correct mapping of the MPV is very important for cardiologists and for surgeons in order to provide the best treatment and avoid complications.