Purpose: To evaluate the sensitivity and accuracy of magnetic resonance arthrography (MRA) with true sagittal scout image mapped radial reformation in localizing hip labral tears.
Type of study: Case series.
Methods: Thirty patients were examined with hip MRA because of suspected labral tears. Every patient underwent normal hip arthrography and MR examinations using a 1.5-T scanner with a 3D-FLASH pulse sequence. Multiplanar reformation using double oblique technique produced radial reformatted rotation images with 10 degrees increment on the acetabular rim. Labral tears were annotated as anterior-superior (AS), anterior-inferior (AI), posterior-superior (PS), and posterior-inferior (PI) quadrant based on the cranial-caudal axis in true sagittal reformatted scout localizing image. Patients with positive MRA findings were counseled to have the arthroscopic hip procedure.
Results: Five patients showed no MRA indication of labral tear. Of 25 patients who had MRA evidence of labral tear, 17 underwent arthroscopic hip surgery. One patient had only synovial process in the hip joint near the suspected MRA area. The remaining 16 operated patients had labral tears with a total of 21 quadrant lesions on arthroscopy (distributed as AS, 14; AI, 3; PS, 2; and PI, 2). Radial reformatted images revealed accurate mapping with arthroscopic findings in 21 of the 22 quadrant lesions. The sensitivity and accuracy of MRA for the diagnosis of hip labral tear were 100% and 94%, respectively, and the sensitivity and accuracy of radial reformatted MRA for mapping the tear location were 100% and 96%, respectively.
Conclusions: MRA using radial reformatted images with a true sagittal localizer may achieve superior success rates in diagnosing hip labral lesions and in guiding the arthroscopist in portal selection, thus rendering location of hip labral tears simpler in surgery. It supplied detailed preoperative information to the surgeon, avoiding unnecessary surgery for patients if the diagnosis was unconfirmed.
Level of evidence: Level III.