PURPOSE: To assess the performance of the hybrid of opposite-contrast MR angiography (HOP MRA) technique, which combines flow dephasing and compensating sequences, in the postoperative evaluation of superficial temporal artery (STA)-middle cerebral artery (MCA) bypass. MATERIALS AND METHODS: Both 3D-HOP MRA and 3D-time-of-flight (TOF) MRA at 1.5 Tesla were performed in 19 patients after STA-MCA bypass. The two techniques were visually evaluated to compare the visualization of distal MCA branches and the length and number of depicted recipient MCA branches. Additionally, for the depicted recipient MCA branches, the contrast-to-noise ratio (CNR) and length were compared between the two techniques. RESULTS: The 3D-HOP MRA provided better visualization of the recipient MCA branches than 3D-TOF MRA in 10 of the 19 patients, while the depicted recipient MCA branches were longer on 3D-HOP MRA than on 3D-TOF MRA in 9 patients. Although not statistically significant, the average number of depicted recipient branches by 3D-HOP MRA (2.16) was greater than that by 3D-TOF MRA (1.79). 3D-HOP MRA was significantly superior to 3D-TOF MRA in both CNR (119.0 versus 74.3) and length of the recipient MCA branches (72.0 versus 49.9 pixels). CONCLUSION: 3D-HOP MRA is superior to 3D-TOF MRA for the detailed evaluation of STA-MCA bypass.
PURPOSE: To assess the performance of the hybrid of opposite-contrast MR angiography (HOP MRA) technique, which combines flow dephasing and compensating sequences, in the postoperative evaluation of superficial temporal artery (STA)-middle cerebral artery (MCA) bypass. MATERIALS AND METHODS: Both 3D-HOP MRA and 3D-time-of-flight (TOF) MRA at 1.5 Tesla were performed in 19 patients after STA-MCA bypass. The two techniques were visually evaluated to compare the visualization of distal MCA branches and the length and number of depicted recipient MCA branches. Additionally, for the depicted recipient MCA branches, the contrast-to-noise ratio (CNR) and length were compared between the two techniques. RESULTS: The 3D-HOP MRA provided better visualization of the recipient MCA branches than 3D-TOF MRA in 10 of the 19 patients, while the depicted recipient MCA branches were longer on 3D-HOP MRA than on 3D-TOF MRA in 9 patients. Although not statistically significant, the average number of depicted recipient branches by 3D-HOP MRA (2.16) was greater than that by 3D-TOF MRA (1.79). 3D-HOP MRA was significantly superior to 3D-TOF MRA in both CNR (119.0 versus 74.3) and length of the recipient MCA branches (72.0 versus 49.9 pixels). CONCLUSION: 3D-HOP MRA is superior to 3D-TOF MRA for the detailed evaluation of STA-MCA bypass.