Fig 1.
A 56-year-old man with cervical OPLL.
(a) Sagittal CT of the cervical spine, showing continuous OPLL (arrowheads) at the level of the C3 through C5 bodies. (b) Sagittal T1WI, showing that the signal intensity of OPLL (arrowheads) is similar to that of the CSF. One reader interpreted these findings as an equivocal finding for OPLL, whereas another reader interpreted them as a probable absence of OPLL. (c) On the sagittal T2WI, the region of OPLL (arrowheads) is not clearly delineated, since its signal intensity is similar to that of the disc. Both readers interpreted these findings as an equivocal finding for OPLL (score 2). (d) mFFE image clearly showing a region of OPLL (arrowheads) exhibiting good contrast with the CSF and disc. This image was correctly interpreted as indicative of the presence of OPLL (score 4) by both readers.
Fig 2.
A 42-year-old man with cervical OPLL and DO.
(a) Sagittal CT image of the cervical spine, showing OPLL with a double-layer DO (arrow) at the C2 body and a single-layer DO (arrowhead) at the C2-3 disc level through the C4 body level. (b) Sagittal T1WI showing various signals of OPLL. DO at the C2 level (arrow) was correctly diagnosed by both readers; however, one reader incorrectly interpreted this signal as a single-layer sign. The DO of the C2-3 disc level through C4 body level (arrowhead) was correctly interpreted as a single-layer sign by both readers. (c) Sagittal T2WI showing various signals of OPLL. The presence of DO at the C2 level (arrow) was correctly diagnosed by both readers; however, both incorrectly interpreted this signal as a single-layer sign. The DO of the C2-3 disc level through C4 body level (arrowhead) was correctly interpreted as a single-layer sign by both readers. (d) Sagittal mFFE image showing a double-layer sign (arrow) and a single-layer sign (arrowhead), which were correctly interpreted as signs of a double-layer and a single layer DO, respectively, by both readers. (e, f) Axial mFFE (E) and axial CT (F) images at the C2 body level (arrow, a-d) showing a double layer sign. (g, h) Axial mFFE (G) and axial CT (H) images obtained at the C3 body level (arrowhead, a-d) showing a single layer sign.
Table 1.
Overall diagnostic performance of MRI in the diagnosis of OPLL.
Table 2.
Overall diagnostic performance of MRI in the diagnosis of DO.
Table 3.
Overall diagnostic performance of MRI in the diagnosis of OPLL and per-lesion analysis at vertebral body levels.
Table 4.
Overall diagnostic performance of MRI in the diagnosis of OPLL and per-lesion analysis at disc levels.
Table 5.
Diagnostic performance of each MR sequence in the diagnosis of OPLL.
Table 6.
Diagnostic performance of each MR sequence in the diagnosis of DO.
Table 7.
Image contrast ratios of each MR sequence.