Study DesignProspective study.PurposeWe evaluated the usefulness of diffusion tensor imaging (DTI) in diagnosing patients with cervical myelopathy by determining the accuracy of normal DTI parameter values.Overview of LiteratureDTI can visualize white matter tracts in vivo and quantify anisotropy. DTI is known to be more sensitive than conventional magnetic resonance imaging (MRI) in detecting subtle pathological changes of the spinal cord.MethodsA total of 31 normal subjects (13 men and 18 women; age, 23-87 years; mean age, 46.0 years) were included in this study. The patients had no symptoms of myelopathy or radiculopathy. A Philips Achieva 3-Tesla MRI with SE-type Single Shot EPI was used to obtain diffusion tensor images. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values were measured as DTI parameters on axial sections of several cervical levels. Subjects were divided into two groups: >40 years (n=16) and ≤40 years (n=15). A paired t-test was used to compare significant differences between the groups. ADC and FA values were most stable on axial sections.ResultsFor all subjects, mean ADC and FA values were 1.06±0.09×10-3 mm2/sec and 0.68±0.05, respectively. ADC was significantly higher in subjects >40 years of age than in those ≤40 years. There was no significant difference in FA values between the two groups. The mean ADC value was significantly higher in normal subjects >40 years of age than in those ≤40 years.ConclusionsIt is important to consider age when evaluating cervical myelopathy by DTI.

Study Design: A retrospective study. Objectives: Diffusion tensor imaging (DTI) reflects pathological change in the spinal cord more sensitively than conventional magnetic resonance imaging (MRI). Electrophysiological examination enables quantitative assessment of spinal cord function. Few studies have addressed the correlation between intraoperative spinal cord-evoked potentials (SCEPs) and DTI. The purpose of this study was to examine whether DTI is an objective index for the diagnosis of the segmental level of dysfunction in cervical spondylotic myelopathy (CSM). Setting: Yamaguchi University Graduate School of Medicine, Japan. Methods: Using 3.0-Tesla MRI, DTI values for the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured at the disc level C2/C3 through C6/C7 in 11 normal subjects and 10 subjects with CSM. Subjects with CSM were divided into two groups based on the extent of compression according to conventional MRI: single level (n = 3) and multilevel (n = 7). Intraoperative SCEPs were measured in subjects with CSM. For each group, the ADC and FA values were compared with SCEPs with respect to the segmental levels of dysfunction. Results: For all three subjects with single-level compression and six of seven with multilevel compression, the maximal ADC value was observed at the segmental level of dysfunction as per the SCEP. Minimum FA values were observed at those sites in two of three patients with single-level compression and in only two of seven with multi-level compression. INTRODUCTIONCervical spondylotic myelopathy (CSM) is diagnosed using magnetic resonance imaging (MRI) and neurological examination. However, the neurological findings are not always typical, and clinical symptoms of CSM may differ between patients. Determination of the segmental levels of spinal cord involvement in CSM can be difficult, particularly in cases involving multi-level compression. In addition, the presence of high-signal intensity lesions on T2-weighted MRI of the cervical spinal cord does not necessarily correspond to myelopathy. Spinal cord-evoked potentials (SCEPs) measured by electrophysiological examination are useful for investigating the functional integrity of the spinal cord, even in cases involving compression at several levels.Diffusion tensor MR imaging (DTI) is an advanced MRI technique that measures the diffusion of water molecules in tissues. Objective and quantitative assessment of microstructural change is possible by means of DTI.Useful DTI parameters include the apparent diffusion coefficient (ADC) and fractional anisotropy (FA). The ADC reflects the diffusive strength of water molecules, regardless of directionality. ADC values thus increase in compressed lesions of the spinal cord. 1 FA measures

No abstract

No abstract

No abstract