Classification of High Intensity Zones of the Lumbar Spine and Their Association with Other Spinal MRI Phenotypes: The Wakayama Spine Study

Abstract

IntroductionHigh intensity zones (HIZ) of the lumbar spine are a phenotype of the intervertebral disc noted on MRI whose clinical relevance has been debated. Traditionally, T2-weighted (T2W) magnetic resonance imaging (MRI) has been utilized to identify HIZ of lumbar discs. However, controversy exists with regards to HIZ morphology, topography, and association with other MRI spinal phenotypes. Moreover, classification of HIZ has not been thoroughly defined in the past and the use of additional imaging parameters (e.g. T1W MRI) to assist in defining this phenotype has not been addressed.Materials and MethodsA cross-sectional study of 814 (69.8% females) subjects with mean age of 63.6 years from a homogenous Japanese population was performed. T2W and T1W sagittal 1.5T MRI was obtained on all subjects to assess HIZ from L1-S1. We created a morphological and topographical HIZ classification based on disc level, shape type (round, fissure, vertical, rim, and enlarged), location within the disc (posterior, anterior), and signal type on T1W MRI (low, high and iso intensity) in comparison to the typical high intensity on T2W MRI.ResultsHIZ was noted in 38.0% of subjects. Of these, the prevalence of posterior, anterior, and both posterior/anterior HIZ in the overall lumbar spine were 47.3%, 42.4%, and 10.4%, respectively. Posterior HIZ was most common, occurring at L4/5 (32.5%) and L5/S1 (47.0%), whereas anterior HIZ was most common at L3/4 (41.8%). T1W iso-intensity type of HIZ was most prevalent (71.8%), followed by T1W high-intensity (21.4%) and T1W low-intensity (6.8%). Of all discs, round types were most prevalent (anterior: 3.6%, posterior: 3.7%) followed by vertical type (posterior: 1.6%). At all affected levels, there was a significant association between HIZ and disc degeneration, disc bulge/protrusion and Modic type II (p<0.01). Posterior HIZ and T1W high-intensity type of HIZ were significantly associated with disc bulge/protrusion and disc degeneration (p<0.01). In addition, posterior HIZ was significantly associated with Modic type II and III. T1W low-intensity type of HIZ was significantly associated with Modic type II.ConclusionsThis is the first large-scale study reporting a novel classification scheme of HIZ of the lumbar spine. This study is the first that has utilized T2W and T1W MRIs in differentiating HIZ sub-phenotypes. Specific HIZ sub-phenotypes were found to be more associated with specific MRI degenerative changes. With a more detailed description of the HIZ phenotype, this scheme can be standardized for future clinical and research initiatives.

Discogenic Back Pain: Literature Review of Definition, Diagnosis, and Treatment

“…This bright area surrounded by a low-intensity (black) signal of the AF is appreciably brighter than the CSF signal at the same level on sagittal T2W MRI of L1 to S1. (17,62,63) HIZ has been shown to correlate with annulus damage and increased pain; it is also consistent with findings on discography. (64,65)…”

“…It commonly requires prolonged treatment, has mixed‐to‐poor surgical outcomes, and opioids are often prescribed . Many studies have demonstrated high sensitivity of pain to IVD pathologies on MRI including high‐intensity zones and Modic changes, although this sensitivity is often not specific to pain presentation. The absence of IVD degeneration on MRI is associated with significantly reduced pain, making it a more specific measure .…”

The association of high-intensity zones on MRI and low back pain: a systematic review

“…Three comparative studies indicated the significant association between HIZs and LBP [ 12 – 17 ] (Table 3 ). Wang et al [ 14 ] reported a clinical series, which included 623 patients (337 males and 286 females, age 50.1 ± 15.4 years), and 200 patients (32.1%) exhibited HIZs in at least one disc.…”

“…Currently, there is no consensus as reports have contradictory evidence and are based on limited evidence from studies without control groups, underpowered, or heterogeneous population studies [ 11 – 23 ]. Regarding some previous studies using discographic injection for HIZ, the relationship between the presence of lumbar HIZs with a concordant pain response on provocative discography was noted as a significant MRI biomarker of the diagnosis of discogenic LBP [ 11 , 12 ]. On the other hand, Ricketson et al [ 27 ] and Buirski et al [ 34 ] were not able to demonstrate a statistically significant correlation between the presence of HIZs and pain concordant with the usual symptoms elicited during provocative discography [ 27 , 34 ].…”

“…Magnetic resonance imaging (MRI) of the lumbar spine is a frequently used imaging tool to characterize spine pathology and possibly identify the source of LBP [ 3 ]. Throughout the years, numerous lumbar phenotypes, such as endplate abnormalities, Modic changes, or black discs, have been identified and studied as potential pain generators to assist clinical decision-making and predicting outcomes [ 8 – 12 ]. However, there is often a discrepancy between what is noted on MRI and the clinical profile, leading to criticism regarding its utility in LBP management [ 13 , 14 ].…”