The assessment of left atrial and pulmonary vein morphology has important applications in the context of atrial fibrillation, a condition in which the atria of the heart beat rapidly and irregularly. Following ablation therapy, a treatment strategy for atrial fibrillation, reverse structural remodeling has been demonstrated with decreases in both left atrial size and pulmonary vein diameters. Most techniques for assessment of pulmonary vein morphology, however, consist of manual measurements made on cross-sectional images or volume renderings, thereby limiting the ability to fully quantify the 3D structure of the veins. In this work, we propose a method to quantify the 3D morphology of the pulmonary veins by computing the cross-sectional area along the entire extent of the vein. A centerline is tracked along the vein and oblique image slices are extracted at each point along the curve. The overall method requires only minimal manual interaction during the data pre-processing steps and is demonstrated on each of the four pulmononary veins in five subjects scanned with CT imaging prior to ablation therapy.