Characterization of alar ligament on 3.0T MRI : A cross-sectional study in IIUM Medical Centre, Kuantan

Abstract

The main purpose of the study is to compare the normal anatomy of alar ligament on MRI between male and female. The specific objectives are to assess the frequency of alar ligament visualized on MRI, to describe its characteristics in term of its course, shape and signal homogeneity. This study also aims to determine the association between gender and height of the respondents with alar ligament signal intensity as well as the association between height of the respondents with ligament dimensions. 50 healthy volunteers were studied on 3.0T MR scanner Siemens Magnetom Spectra using 2-mm proton density, T2 and fat-suppression sequences. Alar ligament was depicted in 3 planes and the visualization and variability of the ligament courses, shapes and signal intensity characteristics were determined. The alar ligament dimensions were also measured. Alar ligament was best depicted in coronal plane, followed by sagittal and axial planes. The orientations were laterally ascending in most of the subjects (60%), predominantly oval in shaped (54%) and 67% showed inhomogenous signal. Females were 70% less likely to exhibit alar ligament signal inhomogeneity than males. There was positive correlation between height and the craniocaudal diameter of the alar ligament as well as the anteroposterior diameter, which were statistically significant (r = 0.25, n = 100, p = 0.01 and r = 0.201, n = 100, p = 0.045 respectively). Employing a 3.0T MR scanner, the alar ligament is best portrayed on coronal plane, followed by sagittal and axial planes. However, tremendous variability of alar ligament as depicted in our data shows that caution needs to be exercised when evaluating alar ligament, especially during circumstances of injury.