The qualitative grading of muscle fat infiltration in whiplash using fat and water magnetic resonance imaging

Confirming the geography of fatty infiltration in the deep cervical extensor muscles in whiplash recovery

“…Consistent with preliminary work 1 , 7 , MFI appears to be equally distributed between the more lateral quartiles at all levels analysed (C4-C7) and across all groups, but, once again, Q1 contains the highest MFI levels with significantly larger magnitudes in the two symptomatic groups compared to the recovered group. This provides supportive data mapping the spatial distribution and magnitude of MFI in the deep extensor muscles in a larger sample of individuals with varying levels of WAD-related disability at one-year post injury when compared to preliminary quantitative 1 and qualitative 7 reports.…”

“…Consistent with preliminary work 1,7 , MFI appears to be equally distributed between the more lateral quartiles at all levels analysed (C4-C7) and across all groups, but, once again, Q1 contains the highest MFI levels with significantly larger magnitudes in the two symptomatic groups compared to the recovered group. This provides supportive data mapping the spatial distribution and magnitude of MFI in the deep extensor muscles in a larger sample of individuals with varying levels of WAD-related disability at one-year post injury when compared to preliminary quantitative 1 and qualitative 7 reports. As a reflection of the natural history of decline in muscle quality with age, it is plausible that the medial aspect of deep paraspinal muscles is susceptible to increased MFI, thereby raising mechanistic questions of whether (i) having higher pre-trauma MFI in Q1 or (ii) the acute trauma-related expressions of Q1 MFI contribute to the clinical course and further degeneration in total MFI over time.…”

“…It is noteworthy that while MFI was reported to be more concentrated in the medial portion of the muscles in all participants 1,7 , the magnitude was significantly greater in a small subgroup of participants with chronic WAD, suggesting a potential phenotypic expression of chronicity. Despite positive findings from both quantitative 1 or qualitative 7 measures, replication of these findings in a larger cohort with varying levels of chronic WAD is required before the pervasive finding of, and specific distribution for, MFI in this population can be confirmed.…”

“…It is noteworthy that while MFI was reported to be more concentrated in the medial portion of the muscles in all participants 1,7 , the magnitude was significantly greater in a small subgroup of participants with chronic WAD, suggesting a potential phenotypic expression of chronicity. Despite positive findings from both quantitative 1 or qualitative 7 measures, replication of these findings in a larger cohort with varying levels of chronic WAD is required before the pervasive finding of, and specific distribution for, MFI in this population can be confirmed. As such, MRI data from participants enrolled in a longitudinal study of WAD recovery were included from the 1-year post injury time point and used to (i) confirm previous results 1 by quantifying the magnitude and spatial distribution of MFI in the deep cervical extensor muscles (multifidus and semispinalis cervicis) and (ii) compare these findings across a population of patients with varying levels of WAD-related disability one-year following the injury event.…”

“…Various investigations across three continents (United States 1 – 3 , Australia 2 , 4 – 6 , and Sweden 7 , 8 ) have used similar manual segmentation methods with magnetic resonance imaging (MRI) to demonstrate widespread fatty infiltrates in the neck muscles of individuals with acute and chronic whiplash associated disorders (WAD). Comparably high levels of muscle fat infiltration (MFI) were not identified in individuals who (i) had recovered or reported lower levels of WAD-related disability 1 , 3 , 4 , 7 , 8 , (2) had chronic non-traumatic neck pain 9 , or (3) those without a history of neck disorders 10 . Knowledge of a precise mechanism for MFI expression and distribution (e.g.…”