Parallel imaging technique for the external carotid artery and its branches: Comparison of balanced turbo field echo, phase contrast, and time‐of‐flight sequences

Abstract

Purpose:To evaluate the parallel imaging technique in the external carotid artery and its branches using 3D balanced turbo field echo (3D bTFE), 3D phase-contrast (3D PC), and 3D time-of-flight (3D TOF) MR angiography (MRA) sequences. Materials and Methods:A total of 26 healthy volunteer subjects underwent 3D bTFE, 3D PC, and 3D TOF MRA with the parallel imaging sensitivity encoding (SENSE) technique. The obtained images were read in a blinded fashion by three radiologists. Interreader and intersequence statistical analyses were performed to compare the visibility of the arteries. Results:Friedman's ranking test demonstrated that there was no significant difference in visibility between any two pairs of sequences for the external carotid artery and its first branches. However, of the three techniques, 3D PC MRA performed the best for the second-order branches (P Ͻ 0.01) and for overall visibility of the external carotid artery and its branches (P Ͻ 0.01). The 3D bTFE sequence is superior to 3D TOF; however, an effective means of separating arteries from veins and salivary ducts is needed. Conclusion:The combination of parallel imaging and the 3D PC technique is a promising approach for face and neck MRA.

Visualization of external carotid artery and its branches: Non–contrast‐enhanced MR angiography using balanced steady‐state free‐precession sequence and a time‐spatial labeling inversion pulse

“…Second, balanced SSFP MRA with a Time-SLIP was not compared with PC MRA. Sumi et al (6) reported that PC with the parallel imaging performed the best for overall visibility of the ECA system among TOF, PC, and balanced SSFP, although arterial spin-labeling method was not used in their study. We did not assess PC MRA because the parallel imaging was not available for PC sequence in the MR scanner used in this study.…”

“…A strong contrast between the blood vessels and muscle can be obtained, but veins and salivary gland ducts as well as arteries show high signal intensity. Sumi et al (6) stated that an effective method of separating arteries from veins and salivary gland ducts was needed for balanced SSFP MRA.…”

“…In "source" evaluation, a total of 11 segments of the ECA system: the main ECA, 8 first-order branches, and 2 second-order branches (the middle meningeal and deep lingual artery), were evaluated for sequences A, B, C, D, and E. These two second-order branches were selected for the evaluation because they showed relatively good visibility in a previous study (6), and were completely covered in the FOV in our study.…”

“…Relatively good visualization of the ECA branches with balanced SSFP has been reported in face and neck region (6,10). However, veins and salivary gland ducts also show high signal intensity in this sequence, which becomes problematic for vessel identification, especially in maximum intensity projection (MIP) images.…”

“…However, saturation effects often lead to signal reduction of the ECA branches in TOF. In PC, motion artifacts caused by a long acquisition time can produce poor visualization of peripheral or movable branches, although the combined use of the parallel imaging and PC has shown good depiction of the ECA system (6).…”