Imaging Diagnosis And Clinical Significance Of The High-Intensity Zone (HIZ)

Objective: To accumulate the epidemiological material of lumbar HIZ and explore its characters and the correlation between the lumbar HIZ and sex, age, body weight or low back pain (LBP). To estimate the value of the HIZ in diagnosing discogenic low back pain and analyzed images with imaging pathological method.Methods: Magnetic resonance images of 1000 lumbar intervertebral discs were retrospective analyzed. The occurrences of HIZs were statisticed and the HIZs were located in 3 dimensions. Five items of 138 cases with full clinical materials, namely, HIZ signs, sex, age, body weight and LBP, were calculated and analyzed for their correlations. Then the presence of HIZ signs of LBP group (160cases) was compared with that of non-LBP group (177 cases). Fourteen lumbar intervertebral discs with HIZ underwent CT/ discography (CTD), and the radiological images were analyzed as well as the results of pain provocation. 138 MRIs and 14 CTDs with HIZ were analyzed for their imaging characters. All data were analyzed with SPSS software.Results: The incidence rate of HIZ among 1000 cases was 46.7% (anterior annulus fibrosus (AF) 21.5%, posterior AF 31.7%). The distribution of HIZs showed no side difference, and there were more HIZs in inferior AF than that of middle or superior AF. HIZs occured more frequently in L_4,5 and L5S1, and could present singly or multiply in whole lumbar discs. There were correlations between the HIZs and sex, age, body weight or LBP in 138 cases. In LBP group, the posterior HIZ rate arrived 38.8% and it was proved that there was difference (x²=9. 619, P<0. 01) between the rate of LBP group and that of non-LBP group (23.2%). The results of CTD showed that 7 lumbar discs (6 patients with LBP) proved concordantly painful and 6 among these displayed the contrast medium escaped from the posterior of the disc. Other 7 discs expressed negative reactions and revealed no agent escaped. In imaging pathological study, HIZs were described as dot-like, round- like, oblong- like or comma- like in sagittal plane and linear or fusiform in transverse plane. HIZs showed the same figures as the cricoid rupture in CTDConclusion: The HIZ is an important sign of vertebral disc degeneration. It represents the cricoid rupture connected with the radial rupture. The HIZ obviously is correlated with sex, age, body weight or LBP. Keep weight in condign range would decrease the risk of HIZ and, further, reduce the occurrence of LBP. The HIZ sign is related to LBP, but have limited diagnostical value. The complete annular disruption is likely to be the cause of discogenic low back pain. Therefore, CTD would not be replaced with HIZ sign in diagnoses.Postgraduate student: Zi-Xuan Wang (Medical image & nuclear medicine) Directed by Prof. Xiang-Min Chen & Prof. You-Gu Hu...