4D Time-Resolved Magnetic Resonance Angiography for Noninvasive Assessment of Pulmonary Arteriovenous Malformations Patency

Purpose: To assess the capability of four-dimensional (4D) time-resolved magnetic resonance angiography (MRA) to assess pulmonary arteriovenous malformations (PAVMs) patency by analyzing pulmonary arterial and venous enhancement kinetics. Materials and Methods: Seven patients with eight documented patent PAVMs underwent a 4D-MRA with keyhole and viewsharing compression at 3T with the following parameters: spatial resolution 0.87 x 0.87 x 1.4 mm(3); field of view 500 x 350 x 238 mm(3); dynamic scan time (temporal resolution) 1.2 seconds; total acquisition time 18.1 seconds for six dynamic datasets (6 x 1.2 sec + reference scan: 10.9 sec). All images were reviewed by two experienced radiologists. Image quality was rated on a qualitative 5-point scale (1: not assessable to 5: excellent). Signal value was measured on cross-sectional planes for the afferent arteries and efferent veins of the PAVM, and for normal reference healthy arteries and veins. The difference in time to peak for each coupled artery/vein (dTTPav) was calculated and compared with a Mann-Whitney test between PAVMs and reference vessels. Results: Mean image quality was 3.2 +/- 0.9. dTTPav was significantly smaller in PAVMs (0.15 +/- 0.76 sec) than in reference vessels (3.75 +/- 1.62 sec), P < 0.001. Conclusion: 4D-MRA is a promising tool for noninvasive assessment of PAVM patency.