Segmental pulmonary arteries: two-dimensional and three-dimensional time-of-flight magnetic resonance angiography

The authors compared two-dimensional (2D) and three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography in ten healthy volunteers to establish which of two techniques is more effective in representing the pulmonary segmental arteries. No respiratory trigger or electrocardiogram gating was used. Presaturation pulses were used to eliminate venous flow. Images acquired in the sagittal planes were processed using maximum intensity projection. A total of 200 segmental arteries were evaluated with each technique by three observers (M.S., C.S., A.R.) in terms of vessel visibility. There was no significant difference among the observers' interpretations (p > 0.05). On average, 2D fast, low-angle shot breath-hold TOF sequences showed 136.1 of 200 (68%) segmental arteries, 74.1 of 100 in the right lung and 62 of 100 in the left lung. Three-dimensional fast imaging with steady state precession showed 171.6 of 200 (85.8%) segmental arteries, 94 of 100 in the left lung and 77.6 of 100 in the left lung. Three-dimensional imaging appeared to be better than 2D MRA for demonstration of segmental pulmonary arteries.