Dataset Information

Diffusion MRI microstructural models in the cervical spinal cord - Application, normative values, and correlations with histological analysis.

ABSTRACT: Multi-compartment tissue modeling using diffusion magnetic resonance imaging has proven valuable in the brain, offering novel indices sensitive to the tissue microstructural environment in vivo on clinical MRI scanners. However, application, characterization, and validation of these models in the spinal cord remain relatively under-studied. In this study, we apply a diffusion "signal" model (diffusion tensor imaging, DTI) and two commonly implemented "microstructural" models (neurite orientation dispersion and density imaging, NODDI; spherical mean technique, SMT) in the human cervical spinal cord of twenty-one healthy controls. We first provide normative values of DTI, SMT, and NODDI indices in a number of white matter ascending and descending pathways, as well as various gray matter regions. We then aim to validate the sensitivity and specificity of these diffusion-derived contrasts by relating these measures to indices of the tissue microenvironment provided by a histological template. We find that DTI indices are sensitive to a number of microstructural features, but lack specificity. The microstructural models also show sensitivity to a number of microstructure features; however, they do not capture the specific microstructural features explicitly modelled. Although often regarded as a simple extension of the brain in the central nervous system, it may be necessary to re-envision, or specifically adapt, diffusion microstructural models for application to the human spinal cord with clinically feasible acquisitions - specifically, adjusting, adapting, and re-validating the modeling as it relates to both theory (i.e. relevant biology, assumptions, and signal regimes) and parameter estimation (for example challenges of acquisition, artifacts, and processing).

SUBMITTER: Schilling KG

PROVIDER: S-EPMC6765439 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Diffusion MRI microstructural models in the cervical spinal cord - Application, normative values, and correlations with histological analysis.

Schilling Kurt G KG By Samantha S Feiler Haley R HR Box Bailey A BA O'Grady Kristin P KP Witt Atlee A Landman Bennett A BA Smith Seth A SA

NeuroImage 20190719

Multi-compartment tissue modeling using diffusion magnetic resonance imaging has proven valuable in the brain, offering novel indices sensitive to the tissue microstructural environment in vivo on clinical MRI scanners. However, application, characterization, and validation of these models in the spinal cord remain relatively under-studied. In this study, we apply a diffusion "signal" model (diffusion tensor imaging, DTI) and two commonly implemented "microstructural" models (neurite orientation ...[more]

PMID: 31326569

Similar Datasets

Project description:PurposeDiffusion-weighted imaging has undergone substantial investigation as a potential tool for advanced assessment of spinal cord health. Unfortunately, commonly encountered surgically implanted spinal hardware has historically disrupted these studies. This preliminary investigation applies the recently developed multispectral diffusion-weighted PROPELLER technique to quantitative assessment of the spinal cord immediately adjacent to metallic spinal fusion instrumentation.MethodsMorphological and diffusion-weighted MRI of the spinal cord was collected from 5 subjects with implanted cervical spinal fusion hardware. Conventional and multispectral diffusion-weighted images were also collected on a normative non-instrumented control cohort and utilized for methodological stability analysis. Variance of the ADC values derived from the normative control group was then analyzed on a subject-by-subject basis and qualitatively correlated with clinical morphological interpretations.ResultsNormative control ADC values within the spinal cord were stable across DWI methods for a b value of 600 s/mm2, though this stability degraded at lower b value levels. Susceptibility artifacts precluded conventional DWI analysis of the cord in subjects with spinal fusion hardware in 4 of the 5 test cases. On the contrary, multispectral PROPELLER DWI produced viable ADC measurements within the cord of all 5 instrumented subjects. Instrumented cord regions without obvious pathology (N = 4) showed ADC values that were lower than expected, whereas one subject with diagnosed myelomalacia showed abnormally elevated ADC.ConclusionsIn the absence of instrumentation, multispectral DWI provides quantitative capabilities that match with those of conventional DWI approaches. In a preliminary instrumented subject analysis, cord ADC values showed both expected and unexpected variations from the normative cohort. These slides can be retrieved under Electronic Supplementary Material.

Project description:ObjectivesDegenerative cervical myelopathy (DCM) involves extrinsic spinal cord compression causing tissue injury and neurological dysfunction. Asymptomatic spinal cord compression (ASCC) is more common, but its significance is poorly defined. This study investigates if: (1) ASCC can be automatically diagnosed using spinal cord shape analysis; (2) multiparametric quantitative MRI can detect similar spinal cord tissue injury as previously observed in DCM.DesignProspective observational longitudinal cohort study.SettingSingle centre, tertiary care and research institution.Participants40 neurologically intact subjects (19 female, 21 male) divided into groups with and without ASCC.InterventionsNone.Outcome measuresClinical assessments: modified Japanese Orthopaedic Association score and physical examination. 3T MRI assessments: automated morphometric analysis compared with consensus ratings of spinal cord compression, and measures of tissue injury: cross-sectional area, diffusion fractional anisotropy, magnetisation transfer ratio and T2*-weighted imaging white to grey matter signal intensity ratio (T2*WI WM/GM) extracted from rostral (C1-3), caudal (C6-7) and maximally compressed levels.ResultsASCC was present in 20/40 subjects. Diagnosis with automated shape analysis showed area under the curve >97%. Five MRI metrics showed differences suggestive of tissue injury in ASCC compared with uncompressed subjects (p<0.05), while a composite of all 10 measures (average of z scores) showed highly significant differences (p=0.002). At follow-up (median 21 months), two ASCC subjects developed DCM.ConclusionsASCC appears to be common and can be accurately and objectively diagnosed with automated morphometric analysis. Quantitative MRI appears to detect subclinical tissue injury in ASCC prior to the onset of neurological symptoms and signs. These findings require further validation, but offer the intriguing possibility of presymptomatic diagnosis and treatment of DCM and other spinal pathologies.

Project description:Background and purposeAlthough current radiologic evaluation of degenerative cervical myelopathy by conventional MR imaging accurately demonstrates spondylosis or degenerative disc disease causing spinal cord dysfunction, conventional MR imaging still fails to provide satisfactory anatomic and clinical correlations. In this context, we assessed the potential value of quantitative cervical spinal cord T1 mapping regarding the evaluation of patients with degenerative cervical myelopathy.Materials and methodsTwenty patients diagnosed with mild and moderate-to-severe degenerative cervical myelopathy and 10 healthy subjects were enrolled in a multiparametric MR imaging protocol. Cervical spinal cord T1 mapping was performed with the MP2RAGE sequence procedure. Retrieved data were processed and analyzed regarding the global spinal cord and white and anterior gray matter on the basis of the clinical severity and the spinal canal stenosis grading.ResultsNoncompressed levels in healthy controls demonstrated significantly lower T1 values than noncompressed, mild, moderate, and severe stenotic levels in patients. Concerning the entire spinal cord T1 mapping, patients with moderate-to-severe degenerative cervical myelopathy had higher T1 values compared with healthy controls. Regarding the specific levels, patients with moderate-to-severe degenerative cervical myelopathy demonstrated a T1 value increase at C1, C7, and the level of maximal compression compared with healthy controls. Patients with mild degenerative cervical myelopathy had lower T1 values than those with moderate-to-severe degenerative cervical myelopathy at the level of maximal compression. Analyses of white and anterior gray matter confirmed similar results. Strong negative correlations between individual modified Japanese Orthopaedic Association scores and T1 values were also observed.ConclusionsIn this preliminary study, 3D-MP2RAGE T1 mapping demonstrated increased T1 values in the pathology tissue samples, with diffuse medullary alterations in all patients with degenerative cervical myelopathy, especially relevant at C1 (nonstenotic level) and at the maximal compression level. Encouraging correlations observed with the modified Japanese Orthopaedic Association score make this novel approach a potential quantitative biomarker related to clinical severity in degenerative cervical myelopathy. Nevertheless, patients with mild degenerative cervical myelopathy demonstrated nonsignificant results compared with healthy controls and should now be studied in multicenter studies with larger patient populations.

Dataset Information

Diffusion MRI microstructural models in the cervical spinal cord - Application, normative values, and correlations with histological analysis.

Publications

Diffusion MRI microstructural models in the cervical spinal cord - Application, normative values, and correlations with histological analysis.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets