Hybrid of opposite‐contrast MRA of the brain by combining time‐of‐flight and black‐blood sequences: Initial experience in major trunk stenoocclusive diseases

Abstract

To assess the feasibility of a new MR angiography (MRA) technique named hybrid of opposite-contrast MRA (HOP MRA) that combined the time-of-flight (TOF) MRA with a flow-sensitive black-blood (FSBB) sequence in the diagnosis of major trunk stenoocclusive diseases. On a 1.5 Tesla imager using a dual-echo three-dimensional (3D)-gradient-echo sequence, we obtained the first echo for TOF MRA followed by the second echo for FSBB. We then subtracted the FSBB data set from that of TOF MRA followed by maximum intensity projection. In four normal volunteers and 19 patients with chronic stenoocclusive disease of the major trunk, we performed HOP MRA along with 3D-TOF MRA and compared the findings. In the volunteer group, the HOP MRA technique improved the demonstration of distal arterial branches. In 12 of the 19 patients, the HOP MRA better visualized branches distal to the lesion as well as distal branches of normal trunks than 3D-TOF MRA, while both techniques provided equivalent depiction of branches distal to the lesion but better depiction of normal distal branches in three patients. The HOP-MRA technique is promising in major trunk stenoocclusive diseases as it better demonstrates distal branches probably representing collaterals than 3D-TOF MRA.