November 15, 1985

Progressive Myelopathy-Reply

Author Affiliations

Veterans Administration Medical Center Wood, Wis

JAMA. 1985;254(19):2741. doi:10.1001/jama.1985.03360190046020

In Reply.—  I agree with the comments of Drs Sarwar and Naseem. Unfortunately, MRI is done in patients with no previous radiographic studies, such as CT. Magnetic resonance imaging has, in my opinion, limited use in the evaluation of calcifications as they appear as low-intensity signals. Plain roentgenograms may demonstrate the abnormality better than MRI studies. Computed tomography due to the axial display of the ligamentum flavum localizes the calcifications well.Dr Olson's comments are well taken. Ligamentous ossification involving the ligamentum flavum or posterior longitudinal ligament contributes to spinal stenosis. Trauma, vascular lesions, and a tendency to ossify ligaments, such as in diffuse idiopathic skeletal hyperostosis (Forestier's disease), are some of the causes of ossification. Ossification may be an associated radiological abnormality, as in patients with thoracic posterior longitudinal ligament ossification.1