The accuracy of MRI in the detection of Lumbar Disc Containment

<p>Abstract</p> <p>Background</p> <p>MRI has proven to be an extremely valuable tool in the assessment of normal and pathological spinal anatomy. Accordingly, it is commonly used to assess containment of discal material by the outer fibers of the anulus fibrosus and posterior longitudinal ligaments. Determination of such containment is important to determine candidacy for intradiscal techniques and has prognostic significance. The accuracy of MRI in detecting containment has been insufficiently documented.</p> <p>Methods</p> <p>The MRI's of fifty consecutive patients undergoing open lumbar microdiscectomy were prospectively evaluated for disc containment by a neuroradiologist and senior spinal surgeon using criteria available in the literature and the classification of Macnab/McCulloch. An independent surgeon then performed the surgery and documented the actual containment status using the same methods. Statistical evaluation of accuracy was undertaken.</p> <p>Results</p> <p>MRI was found to be 72% sensitive, 68% specific, and 70% accurate in detecting containment status of lumbar herniated discs.</p> <p>Conclusion</p> <p>MRI may be inaccurate in assessing containment status of lumbar disc herniations in 30% of cases. Given the importance of containment for patient selection for indirect discectomy techniques and intradiscal therapies, coupled with prognostic significance; other methods to assess containment should be employed to assess containment when such alternative interventions are being considered.</p

Bone marrow fat quantification of osteoporotic vertebral compression fractures: comparison of multi-voxel proton MR spectroscopy and chemical-shift gradient-echo MR imaging.

International audienceBACKGROUND: Only a few studies have used in/opposed phase method for a quantitative evaluation of fat fraction in the spine. PURPOSE: To compare multivoxel proton MR spectroscopy and chemical-shift gradient-echo MR imaging for bone marrow fat quantification in vertebral compression fractures (VCF). MATERIAL AND METHODS: Vertebral marrow fat quantification in fifteen patients was measured at 3.0-T. Multi-voxel proton spectroscopy (MRS) and in/opposed-phase MR imaging using a fat map build with a triple-echo gradient-echo sequence was used. All the patients had benign vertebral collapse. Bone marrow fat content was evaluated by both techniques in compressed (acute or chronic) and in non-compressed vertebrae. RESULTS: The percentage of fat fraction measured by the triple-echo sequence was well correlated with those calculated by MRS (r(2) = 0.85; P < 10(-4)). There was a significant decrease of fat fraction in acute VCF versus both chronic VCF (P < 10(-9)) and non-fractured vertebrae (P < 10(-7)). There was no significant difference in fat fraction evaluated by both techniques between non-fractured vertebrae and chronic VCF. CONCLUSION: We have validated the in/opposed phase method compared with MRS for vertebral bone marrow fat quantification. The fat mapping using a triple-echo gradient-echo sequence allows distinguishing acute and chronic benign VCF