ABSTRACT
BACKGROUND AND PURPOSE: The spinal cord is a site of predilection for MS lesions. While diffusion tensor imaging is useful for the study of anisotropic systems such as WM tracts, it is of more limited utility in tissues with more isotropic microstructures (on the length scales studied with diffusion MR imaging) such as gray matter. In contrast, diffusional kurtosis imaging, which measures both Gaussian and non-Gaussian properties of water diffusion, provides more biomarkers of both anisotropic and isotropic structural changes. The aim of this study was to investigate the cervical spinal cord of patients with MS and to characterize lesional and normal-appearing gray matter and WM damage by using diffusional kurtosis imaging. MATERIALS AND METHODS: Nineteen patients (13 women, mean age = 41.1 ± 10.7 years) and 16 controls (7 women, mean age = 35.6 ± 11.2-years) underwent MR imaging of the cervical spinal cord on a 3T scanner (T2 TSE, T1 magnetization-prepared rapid acquisition of gradient echo, diffusional kurtosis imaging, T2 fast low-angle shot). Fractional anisotropy, mean diffusivity, and mean kurtosis were measured on the whole cord and in normal-appearing gray matter and WM. RESULTS: Spinal cord T2-hyperintense lesions were identified in 18 patients. Whole spinal cord fractional anisotropy and mean kurtosis (P = .0009, P = .003), WM fractional anisotropy (P = .01), and gray matter mean kurtosis (P = .006) were significantly decreased, and whole spinal cord mean diffusivity (P = .009) was increased in patients compared with controls. Mean spinal cord area was significantly lower in patients (P = .04). CONCLUSIONS: Diffusional kurtosis imaging of the spinal cord can provide a more comprehensive characterization of lesions and normal-appearing WM and gray matter damage in patients with MS. Diffusional kurtosis imaging can provide additional and complementary information to DTI on spinal cord pathology.
Subject(s)
Diffusion Tensor Imaging/methods , Image Interpretation, Computer-Assisted/methods , Multiple Sclerosis/complications , Multiple Sclerosis/pathology , Nerve Fibers, Myelinated/pathology , Spinal Cord Injuries/etiology , Spinal Cord Injuries/pathology , Adult , Algorithms , Data Interpretation, Statistical , Female , Humans , Image Enhancement/methods , Male , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
BACKGROUND AND PURPOSE: CC is extensively involved in MS with interhemispheric dysfunction. The purpose of this study was to determine whether interhemispheric correlation is altered in MS by use of a recently developed RS-fMRI homotopy technique and whether these homotopic changes correlate with CC pathology. MATERIALS AND METHODS: Twenty-four patients with relapsing-remitting MS and 24 age-matched healthy volunteers were studied with RS-fMRI and DTI acquired at 3T. The Pearson correlation of each pair of symmetric interhemispheric voxels of RS-fMRI time-series data was performed to compute VMHC, and z-transformed for subsequent group-level analysis. In addition, 5 CC segments in the midsagittal area and DTI-derived FA were measured to quantify interhemispheric microstructural changes and correlate with global and regional VMHC in MS. RESULTS: Relative to control participants, patients with MS exhibited an abnormal homotopic pattern with decreased VMHC in the primary visual, somatosensory, and motor cortices and increased VMHC in several regions associated with sensory processing and motor control including the insula, thalamus, pallidum, and cerebellum. The global VMHC correlates moderately with the average FA of the entire CC for all participants in both groups (r = 0.3; P = .03). CONCLUSIONS: Our data provide preliminary evidence of the potential usefulness of VMHC analyses for the detection of abnormalities of interhemispheric coordination in MS. We demonstrated that the whole-brain homotopic RS-fMRI pattern was altered in patients with MS, which was partially associated with the underlying structural degenerative changes of CC measured with FA.
Subject(s)
Cerebral Cortex/pathology , Cerebral Cortex/physiopathology , Magnetic Resonance Imaging/methods , Multiple Sclerosis, Relapsing-Remitting/pathology , Multiple Sclerosis, Relapsing-Remitting/physiopathology , Adult , Cerebellum/pathology , Cerebellum/physiopathology , Disability Evaluation , Female , Globus Pallidus/pathology , Globus Pallidus/physiopathology , Humans , Male , Middle Aged , Motor Cortex/pathology , Motor Cortex/physiopathology , Pilot Projects , Somatosensory Cortex/pathology , Somatosensory Cortex/physiopathology , Thalamus/pathology , Thalamus/physiopathology , Visual Cortex/pathology , Visual Cortex/physiopathologyABSTRACT
X-ray crystallographic data for 2,9-dimethyl-3'-hydroxy-5-phenyl-6,7-benzomorphan (I) as its p-bromobenzoyl ester are presented. The structure of I is compared with that of morphine, meperidine, alpha-allylprodine, methadone, and moramide as well as with a proposed structure of the enkephalins. A quantitative relationship is found between in vitro opiate receptor binding potency and in vivo analgesia for analgesics of diverse structure, including I. A new view of the analgetic pharmacophore is presented. Programs for the TI Programmable 59 calculator are described for conversion of X-ray crystallographic data to rectangular coordinates with reorientation of the molecule and for the calculation of torsion angles.
