Contrast-enhanced Magnetic Resonance Imaging in Patients with Dropped Head Syndrome

Abstract

Study Design. This is a retrospective study of a consecutive case series of dropped head syndrome (DHS). Objective. To identify the characteristic features of contrast-enhanced magnetic resonance imaging (MRI) in DHS patients. Summary of Background Data. Isolated neck extensor myopathy DHS (INEM-DHS) is thought to be caused by severe cervical extensor muscle weakness from age-related loss of elasticity. However, the MRI findings of the cervical extensor muscles in DHS patients have not yet been characterized. Methods. The subjects were 34 patients with INEM-DHS who underwent contrast-enhanced MRI within 7 months after onset and 32 patients with age-matched cervical spondylosis or cervical soft-tissue tumor as controls. The presence of enhanced findings in the cervical extensor muscles, the involved cervical levels, and the characteristically enhanced shape of those muscles were evaluated using contrast-enhanced MRI. Results. In the DHS group, the contrast-enhanced MRI showed pronounced enhancement at splenius capitis in 34 cases, rhomboid in 23 cases, semispinalis cervicis in 7 cases, and levator scapulae in 3 cases. In the non-DHS group, none of those extensor muscles were enhanced. The enhanced pattern was butterfly-shaped in 29 cases (85.3%) and linear in 5 cases (14.7%). All were located at the spinous process attachment at C6 or C7 in the DHS group. In the non-DHS group, 7 cases presented enhanced image of the spinous process, with C5-6 in 1 case, C6 in 5 cases, and C7 in 1 case. Conclusions. In DHS, contrast-enhanced MRI showed intramuscular enhancement of the cervical extensor muscles, which was not present in non-DHS cases. The enhanced muscles included the splenius capitis muscle in all cases. These findings may be useful for developing a strategy for DHS treatment.