Objective: The aim of this study was to evaluate the diagnostic performance of susceptibility-weighted magnetic resonance imaging (SW-MRI) for the evaluation of osseous foraminal stenosis (FS) of the cervical spine compared to conventional MRI-sequences, using computed tomography (CT) as a reference standard.
Materials and methods: Twenty-one patients with suspected radiculopathy of the cervical spine were prospectively included. CT and MRI data sets were available for all patients. As standard of reference, 280 neuroforamina of the cervical spine, including 58 foraminal stenosis, were identified on sagittal CT images. T1-, T2-, and SW-MRI of the cervical spine were performed. The presence of foraminal stenosis was assessed on sagittal views in all sequences. Sensitivity and specificity were calculated and differences in detection rate and severity scoring of foraminal stenosis between the different sequences were tested. CT was used as reference standard for all analysis.
Results: Fifty-six of 58 osseous foraminal stenosis could be correctly identified on SW-MR magnitude images. SW-MRI achieved a sensitivity of 96.6% and specificity of 99.5% for the identification of foraminal stenosis. In comparison, conventional T1-weighted MRI sequences achieved a sensitivity and specificity of 43.1% and 100% respectively. T2-weighted MRI sequences achieved a sensitivity and specificity of 65.5% and 99.1%, respectively. The overall detection rate was significantly (p < 0.05) higher on SW-MRI and there was no significant difference (p > 0.05) in severity scoring compared to CT. T1- and T2-weighted MRI underestimated the degree of foraminal stenosis. Intermodality and interobserver agreements were highest for SW-MRI.
Conclusions: SW-MRI enables the reliable detection of osseous foraminal stenosis of the cervical spine in patients with spinal radiculopathy with a higher sensitivity compared to conventional T1- and T2-MRI sequences, with CT as a reference standard.
Key points: • Susceptibility-weighted magnetic resonance imaging enables the reliable detection of osseous foraminal stenosis of the cervical spine with CT as a reference standard. • This could be relevant for younger patients in order to prevent unnecessary radiation exposure. • This may also facilitate a one-stop-shop approach and speed up diagnostic work-up.
Keywords: Diagnostic imaging; Magnetic resonance imaging; Radiculopathy; Spine.