Magnetic resonance imaging of the lumbar spinous processes and adjacent soft tissues: normal and pathologic appearances.

The spinous processes and intervening soft tissues of the lumbar region may be involved by degenerative, inflammatory, neoplastic, and traumatic processes resulting in low back pain. While conventional radiography and computed tomography have proven useful in the demonstration of abnormalities affecting the spinous processes, they are of limited utility in the evaluation of the intervening soft tissues, which are the predominant site of initial pathologic involvement. To explore the potential role of magnetic resonance imaging (MRI) in the assessment of the spinous processes and adjacent ligaments, a retrospective review of 55 consecutive examinations of the lumbar spine was performed. The normal and pathologic appearances of the region on both T1 and T2 weighted images were characterized, and the optimal imaging variables for demonstration of the spinous processes and adjacent soft tissues were determined with subsequent prospective application to new cases. Correlative examination of cadaveric sections and dried specimens was also performed to facilitate understanding of anatomical relationships visualized by MRI. Based upon the results of this investigation, MRI is the procedure of choice in the evaluation of disease processes affecting the spinous processes and intervening ligaments, primarily owing to the ability to image directly in the sagittal plane and its superior soft tissue contrast discrimination capability.