Type:
Educational Exhibit
Keywords:
Not applicable, Calcifications / Calculi, Education, MR, Musculoskeletal spine, Anatomy, Musculoskeletal
Authors:
M. Maturi, F. de cecco, G. Mansueto, F. B. Pizzini; Verona/IT
DOI:
10.26044/ecr2020/C-04740
Background
Accurate interpretation of intervertebral disc signal intensity (SI) changes on MRI requires understanding of the anatomy and physiology of the disc in normal and pathological conditions.
In response to stress, degenerative changes occur in various degrees, and it is fundamental to recognize and characterize correctly the different aspects of degenerated intervertebral discs.
Physiology
A normal intervertebral disc is composed by nucleus pulposus, which is a gelatinous structure with high viscosity and high elasticity made of proteoglycans and collagen, and an outer fibrous ring called anulus fibrosus, composed by collagen type II fibers. The structure of the intervertebral disc absorbs and distributes the shock pressure for the spinal load and, together with two adjacent vertebras, constitutes a functional spinal unit.
Changes in intensity on MRI reflect physio-pathological modifications in the disc that evolve over time from a biomechanically related continuum of alterations.
Technique
MRI has the advantage to identify the level -or levels- of alterations and to accurately characterise the physio-pathological changes in intervertebral disc.
Standard sequences for spine examination include:
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T1 weighted TSE (turbo spin echo) on sagittal plane: provides good spatial and anatomical resolution.
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T2 weighted TSE on sagittal plane: represents the most important sequence to evaluate the level of hydration of the intervertebral disc, as well as good spatial resolution.
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STIR (Short tau inversion recovery) on sagittal plane: IR sequences provide fat suppression and high contrast resolution for adjacent vertebral pathologies such as bone marrow edema, infectious involvement and neoplastic disease.
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T1 weighted TSE and/or T2 weighted TSE on axial plane: on specific levels of alterations
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Contrast enhanced (CE) T1 weighted sequence on sagittal and axial plane: contrast enhancement differentiates between a wide range of discal pathologies, for example between degenerative and infectious/neoplastic infiltration of intervertebral disc.