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Biomedical subjects

D Kido

Publications and source records attributed to D Kido.

11 recordsLinked to original sources
PubMed2004

Proton MR spectroscopy detected glutamate/glutamine is increased in children with traumatic brain injury.

Adults with traumatic brain injury (TBI) have been shown by invasive methods to have increased levels of the excitatory neurotransmitter glutamate. It is unclear whether glutamate release contributes to primary or secondary injury and whether its protracted elevation is predictive of a poor outcome. Preliminary studies at our institution in adults found that early increases in magnetic resonance spectroscopy (MRS)-detected glutamate/glutamine (Glx) were associated with poor outcomes. We therefore studied 38 children (mean age, 11 years; range, 1.6-17 years) who had TBI with quantitative short-echo time (STEAM, TE = 20 msec) proton MRS, a mean of 7 +/- 4 (range, 1-17) days after injury in order to determine if their occipital or parietal Glx levels correlated with the severity of injury or outcome. Occipital Glx was significantly increased in children with TBI compared to controls (13.5 +/- 2.4 vs. 10.7 +/- 1.8; p = 0.002), but there was no difference between children with good compared to poor outcomes as determined by the Pediatric Cerebral Performance Category Scale score at 6-12 months after injury. We also did not find a correlation between the amount of Glx and the initial Glasgow Coma Scale score, duration of coma, nor with changes in spectral metabolites, including N-acetyl aspartate, choline, and myoinositol. In part, this may have occurred because, in this study, most patients with poor outcomes were studied later than patients with good outcomes, potentially beyond the time frame for peak elevation of Glx after injury. Additional early and late studies of patients with varying degrees of injury are required to assess the importance to the pathophysiology of TBI of this excitatory neurotransmitter.

Adolescent↗
PubMed2000

Early DAT is distinguished from aging by high-dimensional mapping of the hippocampus. Dementia of the Alzheimer type.

OBJECTIVE: To determine the feasibility of using high-dimensional brain mapping (HDBM) to assess the structure of the hippocampus in older human subjects, and to compare measurements of hippocampal volume and shape in subjects with early dementia of the Alzheimer type (DAT) and in healthy elderly and younger control subjects. BACKGROUND: HDBM represents the typical structures of the brain via the construction of templates and addresses their variability by probabilistic transformations applied to the templates. Local application of the transformations throughout the brain (i.e., high dimensionality) makes HDBM especially valuable for defining subtle deformities in brain structures such as the hippocampus. METHODS: MR scans were obtained in 18 subjects with very mild DAT, 18 healthy elderly subjects, and 15 healthy younger subjects. HDBM was used to obtain estimates of left and right hippocampal volume and eigenvectors that represented the principal dimensions of hippocampal shape differences among the subject groups. RESULTS: Hippocampal volume loss and shape deformities observed in subjects with DAT distinguished them from both elderly and younger control subjects. The pattern of hippocampal deformities in subjects with DAT was largely symmetric and suggested damage to the CA1 hippocampal subfield. Hippocampal shape changes were also observed in healthy elderly subjects, which distinguished them from healthy younger subjects. These shape changes occurred in a pattern distinct from the pattern seen in DAT and were not associated with substantial volume loss. CONCLUSIONS: Assessments of hippocampal volume and shape derived from HDBM may be useful in distinguishing early DAT from healthy aging.

Aged↗
PubMed1999

Improving high-resolution MR bold venographic imaging using a T1 reducing contrast agent.

Recently, a new imaging method was proposed by Reichenbach et al (Radiology 1997;204:272-277) to image small cerebral venous vessels specifically. This method, referred to as high-resolution blood oxygen level-dependent venography (HRBV), relies on the susceptibility difference between the veins and the brain parenchyma. The resulting phase difference between the vessels and the brain parenchyma leads to signal losses over and above the usual T2* effect. At 1.5 T, a rather long TE (roughly 40 msec) is required for this cancellation to become significant, leading to enhanced susceptibility artifacts and a long data acquisition time. In this study, we examine the utility of incorporating a clinically available T1 reducing contrast agent, Omniscan (Sanofi Winthrop Pharmaceuticals, NY, NY), with the HRBV imaging approach to reduce susceptibility artifacts and imaging time while maintaining the visibility of cerebral veins. Using a double-dose injection of Omniscan, we were able to reduce TE from 40 to 25 msec. This led to a decrease in TR from 57 to 42 msec, allowing a 26% reduction in data acquisition time while maintaining the visibility of cerebral venous vessels and reducing susceptibility artifacts. J. Magn. Reson. Imaging 1999;10:118-123, 1999.

Artifacts↗
PubMed1993

Perils and pitfalls of magnetic resonance imaging in the diagnosis of multiple sclerosis. The Rochester-Toronto MRI Study Group.

Purpose. Magnetic resonance imaging (MRI) has come to assume a position of major importance in the diagnostic process for multiple sclerosis (MS). The authors believe that a tendency toward overreliance on MRI results in isolation from clinical findings continues to result in both false-positive and false-negative diagnostic errors. Methods. To evaluate this, MRI results in newly referred patients with clinical findings suggestive, but not diagnostic, for MS, were studied prospectively. Results. Of 99 consecutive referrals for suspected MS, there were 3 false-positive diagnoses of MS and 7 false-negatives, when the MRIs were read in isolation from specific clinical data. None of the scans in the false-negative groups were normal. Representative images of both groups are provided. Conclusion. In newly referred patients who fall short of criteria for definite MS, it remains dangerous for both clinicians and radiologists to rely too heavily only on MRI results.

Adult↗
PubMed1993

White matter lesions and cerebral atrophy on MR images in patients with and without AIDS dementia complex.

OBJECTIVE: The objective of this study was threefold: to determine if the frequency of deep white matter changes and cerebral atrophy seen on MR images is significantly different between patients with and without AIDS dementia complex, to determine if certain patterns of white matter changes are more closely associated with AIDS dementia complex, and to determine if focal lesions within the white matter of the splenium are more common in AIDS dementia complex. MATERIALS AND METHODS: Forty-five patients with AIDS were clinically examined for AIDS dementia complex. MR images from these patients were retrospectively reviewed without knowledge of the clinical results. The presence or absence of white matter abnormalities and cerebral atrophy was evaluated by using graded scales and correlated with the presence or absence of AIDS dementia complex. RESULTS: Ten patients met the criteria for AIDS dementia complex. Eight of 25 patients in whom MR images showed abnormal signal intensity in deep white matter had dementia compared with two of 20 in whom MR showed no changes in deep white matter. The presence of these deep white matter abnormalities was not significantly different between groups with and without dementia (p = .08), although higher grades of deep white matter abnormality were more likely to be associated with AIDS dementia complex. Nine of 19 patients in whom MR images showed atrophy had dementia compared with one of 26 in whom MR showed no atrophy. Atrophy was significantly associated with AIDS dementia complex (p = .001). Eight of 15 patients in whom MR images showed abnormal signal intensity within the white matter of the splenium had dementia compared with two of 30 in whom MR showed normal signal intensity in this area. The degree of abnormality in the splenium was weakly associated with AIDS dementia complex (Kendall's tau = .471, p = .001). CONCLUSION: MR findings of cerebral atrophy and abnormal signal intensity in the splenium are associated with AIDS dementia complex. The presence of generalized deep white matter abnormalities does not differ significantly between patients with and without dementia, although more severe grades of white matter abnormality are more likely to be seen in patients with AIDS dementia complex.

AIDS Dementia Complex↗
PubMed1990

Magnetic resonance imaging findings in HIV cognitive impairment.

Atrophy and white matter changes seen on magnetic resonance imaging scans have been observed in association with the acquired immunodeficiency syndrome dementia complex, but these appear to be late findings relative to clinical expression. We report a new magnetic resonance imaging observation in patients with early cognitive impairment due to human immunodeficiency virus infection. Fifty-two patients had a total of 86 magnetic resonance imaging scans during the study period. All scans were obtained with a 1.5-T system. The proton density spin echo (repetition time of 2000 milliseconds and echo delay time of 30 milliseconds) study demonstrated high-signal lesions in the region of the splenium of the corpus callosum and in the crura of the fornices. The lesions demonstrated no contrast enhancement with gadopentate dimeglumine. Pathological examination was performed in five patients. The fornix-subcallosal abnormality may be related to the memory dysfunction in patients with human immunodeficiency virus-related cognitive impairment.

Adult↗
PubMed1988

Fat-suppression MR imaging of the orbit.

The effect of fat suppression on orbital MR imaging was tested by using a derivative of the Dixon method called chopper fat suppression in eight normal volunteers and eight patients with normal conventional orbital MR studies. Chopper fat suppression requires no postacquisition image processing or increased scan time and can be applied through a wide range of T1 to T2 weighting. In normal orbits, fat suppression was found to be advantageous for imaging the lacrimal gland and the optic nerve. Using fat-suppressed T1- or intermediate-weighted sequences, 2000/30 (TR/TE), the optic nerve was recognized by its high signal intensity relative to adjacent CSF, dural sheath, and surrounding fat. The technique minimized loss of anatomic detail by reducing chemical shift misregistration artifact. Disadvantages included an overall lower orbital signal/noise ratio. When used in conjunction with a TR/TE combination carefully selected for both anatomic region of interest and suspected pathology, the fat-suppression technique has the potential for improving the visualization of orbital lesions.

Adult↗
PubMed1986

Cavum vergae. Association with neurologic abnormality and diagnosis by magnetic resonance imaging.

Cavum vergae is a cavity posterior to the septum pellucidum whose clinical significance has previously been unclear. Ten children are described who presented with neurologic findings and were found to have a cavum vergae or cavum vergae and cavum septum pellucidum by brain computed tomographic (CT) scan. Of the ten patients, five had delayed development, four had macrocephaly, two had learning disabilities, two had abnormal electroencephalograms, and one had Apert's syndrome. No cases of cavum vergae were found in 50 children who had brain CT scans for head trauma. These observations suggest that cavum vergae is a nonspecific brain CT scan finding that can be associated with neurologic abnormality. The results of magnetic resonance imaging of one patient with cavum vergae are also described.

Brain↗
PubMed1979

Reduced incidence of cerebral ischemia following rupture of intracranial aneurysms.

A randomized study was carried out to determine if the administration of reserpine and kanamycin to lower the concentration of vasoactive biogenic monoamines would reduce the incidence of cerebral vascular ischemic complications and death following the rupture of intracranial aneurysms. Twenty-six treated and twenty-eight control (untreated) patients were studied. In the preoperative period, eight control (untreated) patients developed symptomatic cerebral ischemia as opposed to one treated patient. There was no correlation between the preoperative clinical findings of ischemia and angiographic evidence of vasospasm. In the post-operative period four control and one treated patient developed symptomatic cerebral ischemia; vasospasm, as demonstrated by cerebral angiography, paralleled these findings.

Cerebral Infarction↗