Labral Disease

Abstract

Acetabular labrum pathology is associated with early osteoarthritis (OA) of the hip joint. Therefore, early diagnosis and reliable determination of the location and severity of labrum pathology are important to allow for a timely surgical intervention, and thus obviate the risk for the development of advanced osteoarthritic damage. Magnetic resonance imaging (MRI) and MR arthrography (MRA), with their superior soft tissue contrast and capability of multiplanar imaging, are the modalities of choice in noninvasively visualizing the hip joint. However, the acetabular labrum may be difficult to image due to its small size, curved orientation, variable morphological appearance, redundancy of the joint capsule when not distended, and several technical limitations such as the decrease in signal intensity owing to the relatively large distance between the labrum and the coil. MRA combines the advantages of an arthrography including capsule distention and delineation of intra-articular structures with the superior spatial resolution of MRI and remains, despite its potential substitutes and alleged limitations, the imaging modality of choice in patients in whom a labral lesion is suspected. However, MRA by itself does not guarantee an accurate hip joint assessment. Instead, image quality, and thus reliable labrum evaluation, is equally affected by pulse sequence parameter and coil selection. If MRA is not applicable, reliable labrum evaluation without contrast medium administration is feasible, provided that appropriate pulse sequences (i.e., PD-weighted imaging) are being used. High-resolution 3D sequences, which allow for multiplanar and radial reconstructions, are further potential imaging alternatives in the assessment of the hip joint. Today, radial imaging is considered a diagnostic standard of MR hip joint assessment because it facilitates the visualization of the entire acetabular circumference, which is of high value in identifying the exact localization and extent of any existing labrum pathology. Future studies that involve 3 T MR imaging for acetabular labrum imaging will likely show improvements due to increased SNR and CNR, potentially relativizing the traditional concept of hip joint evaluation and MRA.