Optimum conditions for detecting the inferior alveolar artery using phase-contrast magnetic resonance angiography.

The inferior alveolar artery (IAA), accompanied by the inferior alveolar nerve, runs through the mandibular canal. The mandibular canal can be observed by conventional radiography and computed tomography, although it is sometimes difficult to identify on these images. This study examined visualization of the IAA with phase-contrast magnetic resonance angiography (PC-MRA). Phase-contrast magnetic resonance angiography images were obtained in the double oblique sagittal plane by using a two-dimensional, fast, low-angle shot (2D FLASH) sequence in five healthy volunteers. A flow-encoding gradient was applied from anterior to posterior, with velocity-encoding numbers (VENCs) of 10, 8, 6, 4, 2, and 1 cm/s. Two observers subjectively evaluated the detectability of the IAA in three mandibular regions on all PC-MRA images. The IAA appeared as a line of high signal intensity on the PC-MRA images. In the mandibular ramus region, the rating scores at VENCs of 1 and 2 cm/s were significantly higher than those at VENCs of 8 and 10 cm/s ( p < 0.05). In the molar region, the scores at a VENC of 1 cm/s were significantly higher than those at VENCs of 8 and 10 cm/s ( p < 0.05). However, in the premolar region, there was no significant difference among the VENCs ( p = 0.0843), with scores of 0 (poor) or 1 (fair). The IAA was visualized by using PC-MRA at appropriate VENC settings. The optimal condition for detecting the IAA appeared to be at a VENC of 1 cm/s, although the IAA was still not visible in the premolar region. [ABSTRACT FROM AUTHOR]