Biomedical subjects

Andrew J Fabiano

Publications and source records attributed to Andrew J Fabiano.

5 recordsLinked to original sources

PubMed2006

A magnetization transfer MRI study of deep gray matter involvement in multiple sclerosis.

BACKGROUND/PURPOSE: Gray matter involvement in multiple sclerosis (MS) is of growing interest with respect to disease pathogenesis. Magnetization transfer imaging (MTI), an advanced MRI technique, is sensitive to disease in normal appearing white matter (NAWM) in patients with MS. DESIGN/METHODS: We tested if MTI detected subcortical (deep) gray matter abnormalities in patients with MS (n= 60) vs. age-matched normal controls (NL, n= 20). Magnetization transfer ratio (MTR) maps were produced from axial proton density, conventional spin-echo, 5 mm gapless slices covering the whole brain. Region-of-interest-derived MTR histograms for the caudate, putamen, globus pallidus, thalamus, and NAWM were obtained. Whole brain MTR was also measured. RESULTS: Mean whole brain MTR and the peak position of the NAWM MTR histogram were lower in patients with MS than NL (P < .001) and mean whole brain MTR was lower in secondary progressive (SP, n= 10) than relapsing-remitting (RR, n= 50, P < .001) patients. However, none of the subcortical gray matter nuclei showed MTR differences in MS vs. NL, RR vs. SP, or SP vs. NL. CONCLUSIONS: The MTI technique used in this cohort was relatively insensitive to disease in the deep gray matter nuclei despite showing sensitivity for whole brain disease in MS. It remains to be determined if other MRI techniques are more sensitive than MTI for detecting pathology in these areas.

Adult↗

PubMed2005

Interhemispheric asymmetry of brain diffusivity in normal individuals: a diffusion-weighted MR imaging study.

BACKGROUND AND PURPOSE: Previous neuroimaging studies have suggested asymmetries in brain diffusivity may exist. The purpose of this study was to assess whether water diffusivity in deep gray matter structures shown by diffusion-weighted (DW) imaging differs between the right and left cerebral hemispheres in normal individuals. METHODS: Brain MR imaging was obtained in 23 healthy volunteers. A multisection image without diffusion weighting, and images with weighting applied in the read, phase, and section directions with a b-factor of 1000 s/mm(2) were collected. Diffusivity was computed separately in each direction, and the results were averaged to form mean diffusivity maps. Quantitative diffusivity values were obtained from the globus pallidus, putamen, caudate, thalamus, white matter, and CSF by using a standardized region of interest template. Interhemispheric differences were assessed by using a paired sample t test. RESULTS: Mean diffusivity was higher in the: left (mean +/- SD: 0.689 x 10(-3)+/- 0.069 x 10(-3)mm(2)/s) versus right (0.642 x 10(-3)+/- 0.071 x 10(-3)mm(2)/s) caudate (% difference, P value: 7.0%, P = .001); right (0.745 x 10(-3)+/- 0.053 x 10(-3)mm(2)/s) versus left (0.706 x 10(-3)+/- 0.050 x 10(-3)mm(2)/s) globus pallidus (5.2%, P < .001); left (0.720 x 10(-3)+/- 0.059 x 10(-3)mm(2)/s) versus right (0.674 x 10(-3)+/- 0.052 x 10(-3)mm(2)/s) putamen (6.4%, P < .001); right (0.750 x 10(-3)+/- 0.040 x 10(-3)mm(2)/s) versus left (0.716 x 10(-3)+/- 0.031 x 10(-3)mm(2)/s) thalamus (4.5%, P < .001). No significant right versus left difference was seen in the CSF (P = .291), anterior frontal white matter (P = .834), or centrum semiovale (P = .320). CONCLUSION: Gray matter diffusivity may differ between hemispheres of the brain in healthy individuals. Analysis of deep gray matter lesions requires caution, as statistically significant interhemispheric differences may not always be indicative of disease.

Adult↗

PubMed2003

Thalamic involvement in multiple sclerosis: a diffusion-weighted magnetic resonance imaging study.

BACKGROUND AND PURPOSE: Injury to deep gray matter structures in multiple sclerosis (MS) has been suggested by recent neuro-imaging and neuropathology studies. Diffusion-weighted magnetic resonance imaging (MRI) can assess tissue damage with greater sensitivity than conventional MRI. The authors' objective was to assess thalamic gray matter damage by diffusion-weighted imaging in MS patients. METHODS: This was a retrospective study performed at a tertiary care, university-affiliated comprehensive MS center of 82 MS patients and 43 controls. The main outcome measures were thalamic apparent diffusion coefficients (ADCs), whole-brain atrophy (brain parenchymal fraction), fluid-attenuated inversion recovery (FLAIR) hypertense lesion volume, and clinical course. RESULTS: ADCs in the left thalamus were higher in MS patients (0.741 +/- 0.044 x 10(-3) mm2/s) than controls (0.723 +/- 0.036 x 10(-3) mm2/s) (P = .027) and higher in secondary progressive MS patients (0.761 +/- 0.044 x 10(-3) mm2/s) than relapsing-remitting MS patients (0.735 +/- 0.032 x 10(-3) mm2/s) (P = .029). ADCs in the right thalamus were higher in secondary progressive MS patients (0.784 +/- 0.069 x 10(-3) mm2/s) than controls (0.757 +/- 0.038 x 10(-3) mm2/s) (P = .033). In the MS group, left thalamus ADCs correlated negatively with brain parenchymal fraction (r = -0.30, P = .008), total left hemispheric FLAIR lesion volume correlated with ADCs in the left (r = 0.35, P = .001) and right (r = 0.39, P < .001) thalami, and total right hemispheric FLAIR lesion volume correlated with ADCs in the left (r = 0.31, P = .006) and right thalami (r = 0.22, P = .048). CONCLUSION: MS patients have increased water diffusion in the thalamus that is partly associated with clinical course, lesion load, and whole-brain atrophy. Both indirect and direct mechanisms of gray matter injury may play a role in the pathophysiology of MS.

Adult↗

PubMed2002

T2 hypointensity in the deep gray matter of patients with multiple sclerosis: a quantitative magnetic resonance imaging study.

CONTEXT: While gray matter T2 hypointensity in multiple sclerosis (MS) has been associated with physical disability and clinical course, previous studies have relied on visual magnetic resonance imaging (MRI) assessments. OBJECTIVE: To quantitatively determine if T2 hypointensity is associated with conventional MRI and clinical findings in MS. DESIGN: Case-control study. SETTING: University-affiliated community-based hospital. SUBJECTS: Sixty patients with MS and 50 controls. MAIN OUTCOME MEASURES: T2 intensities of the substantia nigra, red nucleus, thalamus, putamen, globus pallidus, and caudate; third ventricular width; total brain T1 (hypointense) and T2 (hyperintense) lesion volumes; Expanded Disability Status Scale (physical disability) score; and disease course. RESULTS: Deep gray matter T2 hypointensity was present in patients with MS in all structures (P<.005) except for the substantia nigra. T2 hypointensity was associated with third ventricle enlargement and higher T2 but not T1 plaque load. The regression model predicting third ventricle width included caudate T2 hypointensity (P =.006). The model predicting T2 lesion load included globus pallidus T2 hypointensity (P =.001). Caudate T2 hypointensity was the only variable associated with disability score in regression modeling (P =.03). All T2 hypointensities differentiated the secondary progressive from the relapsing-remitting clinical courses. The final model (P<.001) predicting clinical course retained T2 hypointensity of the thalamus, caudate, and putamen but not MRI plaques or atrophy. CONCLUSIONS: Gray matter T2 hypointensity in MS is associated with brain atrophy and is a stronger predictor of disability and clinical course than are conventional MRI findings. While longitudinal studies are warranted, these results suggest that pathologic iron deposition is a surrogate marker of the destructive disease process.

Adult↗

PubMedDate not supplied

Trigeminal neuralgia with intraoral trigger points: report of two cases.

A variety of pathologic conditions can cause orofacial pain. Establishing the etiology of the pain is key to providing appropriate treatment. Trigeminal neuralgia (TN) is a relatively uncommon condition and can present a diagnostic challenge to even the experienced dental practitioner. The authors discuss two cases of TN that exhibited intraoral trigger points, which initially resulted in confusion regarding the establishment of a correct diagnosis and treatment.

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