Research of the anatomic variations in normal pulmonary venous drainage population by multi-slice CT angiography

Abstract

Objective To investigate the anatomical variant rate and models of normal pulmonary venous drainage to the left atrium on multi-slice spiral CT angiography (MSCTA). Methods Thoracic 64 MSCTA of 220 consecutive patients with all pulmonary venous drainage to the left atrium from May 2013 to July 2014 in the Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University were retrospectively analyzed. The radiographic anatomy of pulmonary veins was revealed by using muti-planar reconstruction (MPR), maximum intensity projection (MIP) and volume rendering (VR) image post-processing to identify each segment of pulmonary vein drainage and connection between pulmonary veins and the left atrium. The normal pulmonary vein drainage was defined as the independently opening of upper and inferior pulmonary veins to the left atrium in each side and the right middle lobe vein opening to upper pulmonary vein. Anatomic variations of pulmonary veins were determined as single or more than two ostia opening of pulmonary veins, and pulmonary venous segment passed through another lobe to the left atrium. Results Among 220 cases with normal pulmonary venous drainage, the overall incidence of right and left pulmonary variations was 22.7%(50/220). Eight types of anatomical variations in the right lung were found in 38 (17.3%, 38/220) cases, including: (1)The right upper lobe and lower lobe pulmonary vein independently drained to the left atrium with right middle lobe vein joined to right lower lobe in 4 (1.8%, 4/220) cases. (2)Right upper lobe and lower lobe pulmonary vein independently drained to the left atrium with posterior segmental vein of right upper lobe joined to right lower lobe in 2 (0.9%, 2/220) cases. (3)the right upper lobe, middle and lower lobe pulmonary vein independently drained to the left atrium in 16 (7.3%, 16/220) cases. (4)The right apical-anterior, posterior segment vein and lower lobe vein independently drained to the left atrium in 4 (1.8%, 4/220) cases. (5)The right upper lobe, superior segment of lower lobe and basal segment of lower lobe vein independently drained to the left atrium with right middle lobe vein joined to right upper lobe in 2 (0.9%, 2/220) cases. (6)The right upper lobe, lateral and medial segment of middle lobe, lower lobe pulmonary vein independently drained to the left atrium in 6 (2.7%, 6/220) cases. (7)The right apical-anterior, posterior segment, middle and lower lobe vein independently drained to the left atrium in 2 (0.9%, 2/220) cases. (8)The right upper lobe, middle lobe, superior segment of lower lobe and basal segment of lower lobe vein independently drained to the left atrium in 2(0.9%, 2/220) cases. Two types of anatomical variations were found in the left side in 12 (5.5%, 12/220) cases, including: (1)Lower lobe vein joined upper lobe vein to form a common trunk in 8 (3.6%, 8/220) cases. (2)The upper lobe, lingular segment and lower lobe pulmonary vein independently drained to the left atrium in 4 (1.8%, 4/220) cases. Conclusions As revealed by MSCTA, anatomical variations of pulmonary venous drainage to the left atrium are not uncommon and the variant patterns are variable. Key words: Pulmonary vein; Tomography, X-ray computed; Anatomic variant