Utility of MRI for cervical spine clearance after blunt traumatic injury: a meta-analysis.

OBJECTIVES: To quantify the rate of unstable injuries detected by MRI missed on CT in blunt cervical spine (CS) trauma patients and assess the utility of MRI in CS clearance.

METHODS: We undertook a systematic review of worldwide evidence across five major medical databases and performed a meta-analysis. Studies were included if they reported the number of unstable injuries or gave enough details for inference. Variables assessed included severity, CT/MRI specifications, imaging timing, and outcome/follow-up. Pooled incidences of unstable injury on follow-up weighted by inverse-of-variance among all included and obtunded or alert patients were reported.

RESULTS: Of 428 unique citations, 23 proved eligible, with 5,286 patients found, and 16 unstable injuries reported in five studies. The overall pooled incidence is 0.0029 %. Among studies reporting only obtunded patients, the pooled incidence is 0.017 %. In alert patients, the incidence is 0.011 %. All reported positive findings were critically reviewed, and only 11 could be considered truly unstable.

CONCLUSIONS: There is significant heterogeneity in the literature regarding the use of imaging after a negative CT. The finding rate on MRI for unstable injury is extremely low in obtunded and alert patients. Although MRI is frequently performed, its utility and cost-effectiveness needs further study.

KEY POINTS: • There were 16 unstable injuries on follow-up MRI among 5286 patients. • The positive finding rate among obtunded patients was 0.12 %. • The positive finding rate among alert, awake patients was 0.72 %. • MRI has a high false-positive rate; its utility mandates further studies. • The use and role of "confirmatory" tests shows wide variations.