Summary

The purpose was to determine the utility of MRI to define AIIS anatomy and compare our findings to previously reported values obtained using CT scans, and we found that MRI is a sound method to evaluate AIIS anatomy as the results of MRI measurements demonstrate statistical consistency with previously reported literature values in a male population and little difference with a female population.

Abstract

Introduction

Subspine impingement is a common cause of hip pain in young athletes. Radiographs fail to fully define the anatomy of the anterior inferior iliac spine (AIIS) often necessitating the need for computed tomography (CT) .The purpose of this study is to determine the utility of magnetic resonance imaging (MRI) to define AIIS anatomy and compare our findings to previously reported values obtained using CT scans.

Methods

Pelvic MRI including bilateral hips of 50 asymptomatic patients were evaluated, which included 31 females (average height, 1.62 m; BMI, 28.9 kg/m2) and 19 males (average height, 1.74 m; BMI, 27.6 kg/m2). Axial sequence measures included: width and the angle of the AIIS relative to the ilium. MRIs of 58 asymptomatic patients were also evaluated. Measures included: AIIS length, width, and the horizontal, vertical, and straight distances from the AIIS to the acetabular rim. 38 females (average height, 1.61 m; BMI, 28.9 kg/m2) and 20 males (average height, 1.81 m; BMI, 28.4 kg/m2) were included in this portion. Values were normalized for height and BMI. Two observers independently obtained all measures which were then averaged and compared to literature reported CT values.

Results

Measures of AIIS anatomy were successfully obtained on all MRI sequences. Male values showed statistical consistency with literature values in all BMI-normalized measures except length and height of AIIS. Comparison of female values to literature values was statistically different in all BMI-normalized measures except for angle to ilium.

Discussion And Conclusion

MRI is a sound method to evaluate AIIS anatomy. The results of MRI measurements demonstrate statistical consistency with previously reported literature values in the male population but not the female population. This small statistically significant difference may be of little clinical significance and likely reveals a difference between the female populations studied.