Magnetic resonance discography in cadavers: tears of the annulus fibrosus

The purpose of this study was to investigate the diagnostic capabilities of magnetic resonance discography in the detection of tears of the annulus fibrosus, and to compare the findings with those derived from conventional magnetic resonance imaging. Twenty-four intervertebral discs from cadavers were examined with magnetic resonance imaging and magnetic resonance discography, and anatomic correlation was done. Forty-six annular tears were documented on anatomic inspection of the specimens. Magnetic resonance discography allowed significantly better observation of radial than transverse annular tears, and identification of radial tears was significantly better than that of concentric tears. With magnetic resonance discography, detectability of concentric tears was not significantly better than that of the transverse tears. No significant differences in the detection of different types of annular tears were appreciated on the magnetic resonance images obtained before discography. Magnetic resonance discography allowed direct diagnosis of radial, transverse, and concentric tears in 100%, 57%, and 21% of specimens, respectively. With magnetic resonance imaging, the diagnosis of radial, transverse, and concentric tears was possible in 67%, 71%, and 21% of specimens, respectively. Magnetic resonance discography does well in the evaluation of the clinically important radial tears of the annulus fibrosus, although not uniformly well in the identification of other types of annular tears.