Improved visualization of superficial temporal artery using segmented time-of-flight MR angiography with venous suppression at 7T

Abstract

Purpose: To evaluate the quality of time-of-flight MR angiography (TOF-MRA) with venous suppression at 7T on imaging superficial temporal artery (STA).

Methods: A recently developed segmented TOF technique with reduced specific absorption rate (SAR) of venous suppression (VS) module was employed to achieve high-resolution arterial angiography without the contamination of venous signal. Images of segmented TOF with VS at 7T, TOF without VS at 7T, and TOF with VS at 3T were collected on 17 healthy volunteers. The number of STA branches and their local contrast achieved by the three methods were quantified and compared using paired t test.

Results: Segmented TOF with VS at 7T successfully suppressed venous signal without reducing the contrast of arterial angiography. The numbers of STA branches in 7T images were significantly higher than that in 3T images (5.79 vs. 4.50, p < 0.001). The contrast of 7T segmented TOF was significantly higher than 3T TOF (7.21 vs. 5.56, p = 0.006).

Conclusion: Segmented TOF with VS at 7T displayed more branches of STA, while eliminating the signal of superficial temporal vein (STV). The improved visualization of STA will potentially facilitate the pre-operative assessment of STA in STA-MCA bypass surgery.

Keywords: 7T MRI; Bypass surgery; Specific absorption rate (SAR); Superficial temporal artery (STA); Time-of-flight MR angiography (TOF-MRA).