Multidetector helical CT is revolutionizing imaging of the thoracic vasculature. Multidetector helical CT allows high-resolution, noninvasive, volumetric imaging that can be acquired during a single breath-hold, making it the imaging study of choice over conventional catheter angiography. In addition, volumetric helical imaging allows three-dimensional reconstruction of data, which is useful in lesion detection, characterization, and surgical planning. With multidetector helical CT, radiologists can definitively characterize pulmonary vascular lesions. Understanding the anatomy, physiology, and imaging appearance of pulmonary vascular lesions is essential in making the correct diagnosis and avoiding unnecessary interventions. This pictorial essay will illustrate multidetector helical CT manifestations of a variety of pulmonary vascular malformations including congenital and acquired lesions.