Magnetic resonance arthrography of the acetabular labrum: value of radial reconstructions

Plotz, GMJ Brossmann, J von Knoch, M Muhle, C Heller, M Hassenpflug, J

Gmj. Plotz et al., Magnetic resonance arthrography of the acetabular labrum: value of radial reconstructions, ARCH ORTHOP, 121(8), 2001, pp. 450-457

17

INGLESE

Article

Ortopedics, Rehabilitation & Sport Medicine

ARCHIVES OF ORTHOPAEDIC AND TRAUMA SURGERY

0936-8051 → ACNP

121

8

2001

450 - 457

ISI

0936-8051(200109)121:8<450:MRAOTA>2.0.ZU;2-S

The intention was to compare the sensitivity and specificity of radial plan es with oblique coronal and oblique axial planes for the detection of labra l abnormalities of the acetabulum on magnetic resonance arthrography (MRa). Twenty cadaveric hip joints were examined by radiography and MRa. For MRa, 15 ml of a solution of iodinated contrast material and gadolinium diethyle ne triamine tetra-acetic acid (Gd-DTPA; 100:1) were injected under fluorosc opic guidance. MRI was performed on a 1.5-T MR scanner with a fat-suppresse d 3D-FLASH sequence (TR/TE/flip-angle 42 ms/10 ms/40 degrees; field of view 16 cm, matrix 256 x 256, section thickness 1.5 mm, pixel size 0.7 X 0.7 mm ). Multiplanar image reconstructions were done perpendicular to the acetabu lum in oblique coronal and oblique axial planes and in radial planes. Macro scopic and histopathologic examination of the labral specimens was performe d. Labral lesions were found in 15/20 hips (75%) on pathologic examination. Six hips demonstrated labral degeneration. The labrum was partially detach ed in 7 hips and completely detached in 2 hips. A flap-like labrum was foun d in 2 cases, 1 with partial detachment of the labrum and 1 with a degenera ted labrum. Using oblique coronal and oblique axial reconstructions, pathol ogic findings were confirmed by MRa in 9/15 specimens (sensitivity 60%). Th ere were no false-positive findings (specificity 100%, accuracy 70%). Also, 3/6 labral degenerations without detachment, 4/7 partial detachments, and 2/2 complete detachments were correctly diagnosed. Two flap-like labra were not recognized. With radial reconstructions, pathologic findings were corr ectly confirmed in 12/15 specimens (sensitivity 80%) without false-positive findings (specificity 100%, accuracy 85%). Also, 3/6 labral degenerations without detachment, 6/7 partial detachments, 2/2 complete detachments, and 1/2 flap-like labra were correctly diagnosed. MRa of the acetabular labrum using radial reconstructions is well suited to delineate the acetabular lab rum and to diagnose labral detachments. Radial reconstructions allow for pe rpendicular display of the whole acetabular circumference and are more accu rate for the diagnosis of acetabular labral lesions, when compared with obl ique coronal and oblique axial reconstructions.