Pulmonary MR angiography: a comparison of 2D and 3D time-of-flight

To compare two-dimensional (2D) time-of-flight (TOF) MR angiography and three-dimensional (3D) TOF MR angiography for visualization of pulmonary arteries and to determine whether pulmonary veins can be viewed selectively.

Imaging was performed using a 1.5 T superconducting MR system with a body coil. Three kinds of 2D TOF MR angiography were compared in four normal volunteers: using a 2D fast low angle shot (FLASH) without cardiac gating and both with and without breath-holding and using a T2-weighted TurboFLASH with cardiac gating and breath-holding. Two-dimensional TOF MR angiography using a T2-weighted TurboFLASH with cardiac gating and breath-holding and 3D TOF MR angiography using fast imaging with steady precession with neither cardiac gating nor breath-holding were compared in four other normal volunteers. Two-dimensional TOF MR venography with a presaturation pulse to suppress artery signals was evaluated in another four normal volunteers.

Three-dimensional TOF MR angiography appeared to be better than 2D TOF MR angiography for delineating pulmonary arteries in the volunteers. The third order branches of peripheral pulmonary veins were distinguishable on 2D TOF MR venography using a presaturation pulse.

Three-dimensional pulmonary TOF MR angiography is useful in demonstrating pulmonary arteries whereas 2D TOF MR venography with a presaturation pulse is useful in showing pulmonary veins.