BACKGROUNDDiscography is a gold standard for the diagnosis of the low back pain (LBP), but it has potential dangers for the development of discitis, cerebral spinal fluid leakage, retroperitoneal bleeding, acute new back pain and the tremendous radiation exposure to the patient. Using "evidence-based radiology" methods, the comparative roles of high intensity zone (HIZ) in diagnosing discogenic LBP were evaluated.

METHODSA focused clinical question was designed and a Pubmed and manual search were performed to identify the role of HIZ on MRI T2WI compared with discography. The studies retrieved were assessed for validity and strength. Sensitivity, specificity, likelihood ratios (LRs) and graphs of conditional probability were evaluated from the best current study by evidence-based radiology.

RESULTSBest evidence was retrieved in ten articles from 1992 to 2007. The best evidence level was 1b and the strength of the evidence included: sensitivity 0.63 (0.51, 0.76), specificity 0.97 (0.92, 1.00), positive predictive value 0.95, negative predictive value 0.72, positive LRs 18.37 and negative LRs 0.38. The gold standard of discogenic LBP is the provocative discography.

CONCLUSIONSFor suspected discogenic LBP, HIZ is limited for the diagnosis if HIZ is positive, which suggests further discography. In contrast HIZ is a good test for diagnosis if HIZ is negative, which indicates the disease can be excluded.