MR arthrography of the adult acetabular capsular-labral complex: Correlation with surgery and anatomy

OBJECTIVE. Our purpose was to describe the appearance of the acetabular cap sular-labral complex on MR arthrography and to correlate this appearance wi th surgical findings in adult patients and with gross anatomic findings in cadavers, SUBJECTS AND METHODS. MR arthrography of the hip joint was performed in 40 patients and six cadavers. All patients underwent subsequent arthrotomy of the hip. MR arthrography consisted of a T1-weighted three-dimensional gradi ent-echo sequence in both the coronal oblique and sagittal oblique planes a fter intraarticular injection of a 2 mmol/l solution of gadopentetate dimeg lumine, The normal and pathologic appearance of the capsular-labral complex was assessed, and the labra were evaluated on the basis of morphology, sig nal intensity, presence of a tear, and attachment to the acetabulum. MR art hrography findings were correlated with the surgical results in all patient s and with the anatomic sections of the cadaveric hip joint specimens. RESULTS. MR arthrography images of the T1-weighted three-dimensional gradie nt-echo sequences allowed visualization of the anatomic structures, The nor mal labrum was triangular, without any sublabral sulcus, and of homogeneous low signal intensity. A recess between the labrum and the joint capsule co uld be identified in instances in which no thickened labrum was present. La bral lesions included labral degeneration, a rear, or a detached labrum eit her with or without thickening of the labrum. The sensitivity for detection and correct staging of labral lesions with MR arthrography in the patient study was 91%; the specificity, 71%; and the accuracy. 88%. CONCLUSION. MR arthrography with T1-weighted three-dimensional gradient-ech o sequences allows excellent assessment of the normal and pathologic acetab ular capsular-labral complex.