Variations of pulmonary vein drainage critical for lung resection assessed by three‐dimensional computed tomography angiography

BACKGROUND: It is important to understand pulmonary vein drainage pattern variations and their frequency in order to perform safe anatomical pulmonary resection. METHODS: Variations and frequencies were assessed using three‐dimensional computed tomography angiography (3D‐CT) in 194 patients. In cases where the tumor or lymph node caused atelectasis or compression of hilar structures, the involved lobes were excluded from the analyses. RESULTS: We confirmed variant drainage patterns in 15/189 (8.0%) patients in the right upper lobe (RUL), 29/189 (15.3%) in the right middle lobe (RML), 18/192 (9.5%) in the right lower lobe (RLL), and 5/187 (2.6%) in the left upper lobe (LUL). There was no variant type in the left lower lobe (LLL). There were 14 (7.4%) cases of anomalous superior posterior pulmonary vein of RUL (V(2)) drainage: V2 draining to the superior pulmonary vein (SPV) (n = 2, 1.1%), V2 to the inferior pulmonary vein (IPV) (n = 7, 3.7%), V2 to the left atrium (LA) (n = 2, 1.1%), and V(6) to the apical pulmonary vein of the RLL (n = 3, 1.6%). There was a posterior pulmonary vein, V(3) to RML pulmonary vein in one case (0.5%). The RML pulmonary vein drained into the IPV in 14 (7.4%) and into the LA in 15 (7.9%) cases. The right V6 directly drained into the LA in 15 (7.9%) and V(6) into the SPV in 3 (1.6%) cases. The lingular pulmonary vein drained into the IPV in one case (0.5%) and into the LA in two cases (1.1%). The inferior lingular pulmonary vein V(5) drained into the IPV and into the LA in one case (0.5%), respectively. CONCLUSION: We describe anomalous pulmonary venous drainage patterns and their frequencies particular to anatomic surgical resection. 3D‐CT is useful to find such variations.