Cervical degenerative disease at flexion-extension MR imaging: prediction criteria.
OBJECTIVE
To determine if there are any neutral-position imaging criteria that can help predict functional cord impingement at flexion-extension cervical magnetic resonance (MR) imaging.


METHODS
Sixty-two patients with cervical degenerative disease were evaluated with regard to the dynamic changes of canal stenosis at flexion-extension MR imaging. Functional cord impingement was considered if the cord was impinged or more impinged after neck flexion or extension. Selection criteria for neutral-position MR imaging, such as cervical curvature, canal space, degenerative stage, intramedullary high signal intensity on T2-weighted images, and resting instability, were evaluated for their ability to predict functional cord impingement at flexion-extension MR imaging (Fisher exact test, logistic regression analysis).


RESULTS
MR images in 19 (31%) of 62 patients showed functional cord impingement at extension MR imaging compared with images in two (3%) patients at flexion MR imaging. Statistically significant differences were found for the criteria cervical degeneration stage (P <.001) and spinal canal space (P =.037) for predicting functional cord impingement at extension MR imaging. In contrast, no significant differences were found among selection criteria for flexion MR imaging. Probabilities of functional cord impingement at extension MR imaging were calculated with different combinations of degenerative stages and canal spaces. Probability could increase to 79% if the patient had both stabilization degeneration (disk protrusion or osteophytic formation with hypertrophy of the ligamentum flavum) and C7 canal space of 10 mm or less.


CONCLUSIONS
None of the selection criteria evaluated in this study has the ability to predict functional cord impingement at flexion MR imaging; however, prediction of impingement at extension MR imaging can increase from 31% to 79% if proper criteria are selected.
Chen
Chi-Jen
CJ
Second Department of Diagnostic Radiology, Chang Gung Memorial Hospital, 199 Tung-Hwa North Rd, Taipei, Taiwan. radcjc@adm.cgmh.org.tw
Hsu
Hui-Ling
HL
Niu
Chi-Chien
CC
Chen
Tzu-Yung
TY
Chen
Min-Chi
MC
Tseng
Ying-Chi
YC
Wong
Yon-Cheong
YC
Wang
Li-Jen
LJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019636:Neurodegenerative Diseases / Q000473:pathology* / Q000503:physiopathology; D011237:Predictive Value of Tests; D013118:Spinal Cord Diseases / Q000473:pathology* / Q000503:physiopathology