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Biomedical subjects

Y Miki

Publications and source records attributed to Y Miki.

336 records · Page 19Linked to original sources
PubMedDate not supplied

Epidural venous system (meningorachidian venous plexus) in juvenile amyotrophy of distal upper extremity: assessment with GD-DTPA enhanced volumetric MR study.

The epidural venous system (meningorachidian venous plexus) was analyzed utilizing gadolinium-diethylenetriamine pentaacetic acid (DTPA) (Gd-DTPA) enhanced volumetric magnetic resonance (MR) images in 11 patients with focal cervical spinal cord atrophy, clinically consistent with juvenile amyotrophy of distal upper extremity. In our series, all of the patients showed unusual posterior epidural venous enhancement at the C5-6 level, suggesting posterior epidural venous dilatation. Three patients also showed prominent dilatation of cervico-thoracic epidural veins surrounding the thecal sac. These MR findings were also demonstrated by spinal phlebography. Gd-DTPA enhanced MR images, especially high resolutional volumetric MR images, were efficient for evaluating these vessels. The observation of meningorachidian venous plexus along the disease course should be necessary for searching the pathogenesis of this disease.

Adolescent↗
PubMedDate not supplied

Differentiation of suprasellar nonneoplastic cysts from cystic neoplasms by Gd-DTPA MRI.

Magnetic resonance imaging in 9 cases of surgically confirmed nonneoplastic intra- and/or suprasellar cysts was analyzed and compared with that from 17 cases of craniopharyngioma and 12 of cystic pituitary adenoma. Signal intensity did not help in distinguishing nonneoplastic cysts from cystic neoplasms. No postcontrast (Gd-DTPA) cyst wall enhancement was observed among the nonneoplastic cysts, although all 6 craniopharyngiomas and 12 cystic pituitary adenomas that underwent postcontrast study did enhance. Three nonneoplastic cysts were surrounded by the pituitary gland, thus mimicking wall enhancement in the postcontrast studies. Rapid enhancement in the early postcontrast-administration phase (dynamic studies) helped avoid confusion between the normal pituitary tissue and cyst wall enhancement. Magnetic resonance studies with contrast enhancement play an essential role in differentiating nonneoplastic cysts from cystic neoplasms in the sella region.

Adenoma↗
PubMedDate not supplied

Contrast enhanced area of posterior pituitary gland in early dynamic MRI exceeds hyperintense area on T1-weighted images.

Seventeen normal pituitary glands were studied by midline sagittal (and in one case axial) dynamic MRI before and immediately after injection of Gd-DTPA, using spin-echo sequences with a short repetition time. Images were obtained at 1 min intervals for 6 min at 1.5 T. A well-defined focal area with marked enhancement was seen in the posterior portion of the pituitary gland on the first image after injection of Gd-DTPA. The size of the early enhancing area in the posterior pituitary (EEPP) was compared with the high signal of the posterior pituitary (HSPP) on the precontrast image. The EEPP was larger than the HSPP in 10 cases (59%). The two were equal in size in seven cases (41%). The EEPP was anteriorly convex in 11 cases (65%), whereas HSPP was anteriorly convex in 4 cases (24%). We believe that EEPP closely represents the real extent of the posterior lobe. Our results support the hypothesis that HSPP may involve only a portion of the posterior pituitary.

Contrast Media↗
PubMedDate not supplied

Degeneration of the posterior columns of the spinal cord: postmortem MRI and histopathology.

Postmortem MR images of two cases of posterior column degeneration were correlated with histopathological findings. The abnormal MR findings were volume loss and high signal intensity of the posterior columns associated with mild deformity of the dorsal surface of the spinal cord, corresponding to tract degeneration on histopathological examination. These results strongly suggest that further development of MR technique will permit in vivo detection of posterior column degeneration.

Adult↗
PubMedDate not supplied

A new computer-assisted method for the quantification of enhancing lesions in multiple sclerosis.

PURPOSE: Our goal is to describe a new computerized method for the detection and quantification of enhanced multiple sclerosis (MS) lesions. METHOD: Gd-DTPA-enhanced, thin section, T1-weighted images of seven patients (involving 336 slice images) with definite MS were analyzed using a new method based on the theory of "fuzzy connected components," developed and implemented on the 3DVIEWNIX software system. Four neuroradiologists selected "true" lesions from the computer-detected potential lesions with a yes/no response to the program query on 2 different days. The enhanced lesion volume and number of enhancing lesions for each image and each observer were subsequently computed. Additional studies involving 720 slices were conducted to determine lesions that were missed by the system. RESULTS: The intra- and interobserver variability in the system was 0%. It took approximately 1 min of operator time per 3D study. The system output has no false positives and a mean false-negative volume of 1.3%. CONCLUSION: The novel system calculates enhancing lesion volume and the number of enhancing lesions with very little operator time, inter- and intraoperator variability, or false-positive and false-negative volumes. Computer-based quantification of enhancing lesion volume is an important objective measure of the activity of MS. The system is now in routine use in clinical investigations that study the role of enhancing lesions in the MS disease.

Brain↗
PubMedDate not supplied

Serial analysis of magnetization-transfer histograms and Expanded Disability Status Scale scores in patients with relapsing-remitting multiple sclerosis.

BACKGROUND AND PURPOSE: Magnetization transfer ratio histogram peak height (MTR-HPH) has been shown to correlate with macroscopic and microscopic brain disease in patients with multiple sclerosis (MS). We studied the changes in MTR-HPH and in Kurtzke's Expanded Disability Status Scale (EDSS) scores over time in a group of patients with relapsing-remitting MS. METHODS: Twenty adult patients with relapsing-remitting MS (four men and 16 women) were followed up for a period of 334 to 1313 days. In all, 86 MR imaging studies of the brain were obtained, and MTR-HPH was calculated for each MR examination by using a semiautomated technique. Changes in MTR-HPH were compared between patients over the study's duration. A neurologist specialized in the care of MS patients assessed the EDSS score for each patient as a measure of clinical disability. RESULTS: Serial MR data showed a subtle but significant decline in MTR-HPH with time. No significant changes in EDSS scores were noted over the same period. CONCLUSION: Patients with relapsing-remitting MS have a significant progressive decline in normalized MTR-HPH, which is independent of EDSS score. MTR-HPH measurements can be used to monitor subclinical disease in patients with relapsing-remitting MS over a short time frame of 1 to 4 years. This parameter might be applied in future therapeutic trials to assess its usefulness.

Adult↗
PubMedDate not supplied

Magnetization transfer histogram analysis of monosymptomatic episodes of neurologic dysfunction: preliminary findings.

BACKGROUND AND PURPOSE: Patients presenting with a monosymptomatic episode of neurologic dysfunction (MEND) have a high probability of developing multiple sclerosis (MS). Our study was designed to determine whether magnetization transfer (MT) histogram analysis could predict the development of MS for a cohort of patients presenting with a MEND. METHODS: Eleven patients with a MEND and 21 age-matched control volunteers underwent MR imaging. Six patients underwent serial MR examinations. MT ratio histogram peak height (MTRHPH) and the location of the MT ratio histogram peak (LOC MTRHP) were determined for patients and control volunteers. T2 lesion volume was also calculated. Patients were clinically followed up for 587 +/- 308 days to determine or rule out the development of MS. RESULTS: Three patients went on to develop MS. There was no statistically significant difference in the MTRHPH (P = .65) and the LOC MTRHP (P = .71) between patients and control volunteers. For those patients who underwent multiple examinations, no statistically significant differences in the MTRHPH (P = .64), LOC MTRHP (P =.58), and T2 lesion volume (P = .47) were seen. There were no statistically significant correlations between any of the parameters studied. CONCLUSION: We found no difference in MT histogram parameters among control volunteers, patients with a MEND without MS, and patients with a MEND who went on to a diagnosis of MS. Our preliminary findings suggest that there may not be a substrate of disease in the normal-appearing white matter that is predictive of the development of MS.

Adult↗
PubMedDate not supplied

Three-dimensional MR vascular imaging of the spine using gadolinium-DTPA.

To investigate the fine vascular structures in the spinal and paraspinal region, the authors performed three-dimensional GRASS scanning after the administration of contrast material. The scan sequence was sagittal volume scan, TR/TE 100/16, with a flip angle of 45 degrees. First-order gradient moment nulling was employed. Four normal volunteers and 31 patients were studied. Using this technique, longitudinal anterior epidural veins and vertebral arteries were clearly identified. Paraspinal fine vessels of slow to moderate flow, including dilated anterior spinal artery, radiculo-medullary vein, and perimedullary coronal venous plexus, were demonstrated in pathological cases. In addition, with processing of the volume data set, phlebographic projection images of the ladder-shaped anterior epidural venous system could be generated. This method provided more detailed information on epidural and intradural vessels than conventional MR imaging.

Contrast Media↗
PubMedDate not supplied

Differential effects of propentofylline on the production of cytokines by peripheral blood mononuclear cells in vitro.

The effects of the xanthine derivative propentofylline on the production of interleukin-6 (IL-6), interleukin-1 beta (IL-1 beta), and tumor necrosis factor-alpha (TNF-alpha) by human peripheral blood mononuclear cells (PBMCs) were studied. When PBMCs were cultured with propentofylline in vitro, the production of IL-6 was markedly increased at concentrations of 0.1 to 3.0 mmol/L of propentofylline and the production of IL-1 beta was slightly increased at concentrations of 1.0 to 3.0 mmol/L. However, an insignificant increase in TNF-alpha production was observed. When the effects of propentofylline on the production of IL-6, IL-1 beta, and TNF-alpha by OK-432-stimulated PBMCs were examined, IL-6 secretion was not significantly increased, whereas production of IL-1 beta and TNF-alpha were significantly suppressed in a dose-dependent manner. The results demonstrate that propentofylline has a differential effect on the production of IL-6, IL-1 beta, and TNF-alpha by PBMCs, and it is proposed that propentofylline may exert pharmacologic actions on the regulation of the production of cytokines in the central nervous system.

Adult↗
PubMedDate not supplied

A case of aleukemic monocytic leukemia cutis treated with total body electron therapy.

A 39-year-old man with aleukemic monocytic leukemia cutis was treated with total skin electron therapy. The patient was irradiated twice a week for five weeks using three overlapping beams (SSD 145 cm) in a four-field technique with 4 MeV electrons. After delivery of 20 Gy, the nodular lesions disappeared. The patient tolerated the treatment well and showed no serious side effects.

Adult↗
PubMedDate not supplied

Comparison of T2 lesion volume and magnetization transfer ratio histogram analysis and of atrophy and measures of lesion burden in patients with multiple sclerosis.

PURPOSE: The purpose of this study was twofold: first, to compare two different measures of lesion burden in patients with multiple sclerosis (MS), the magnetization transfer ratio (MTR) histogram and T2 lesion volume; and, second, to investigate the relationship between lesion burden and atrophy in patients with MS. METHODS: Thirty patients with MS were examined with MR imaging, including fast spin-echo T2- and proton density-weighted sequences as well as magnetization transfer sequences. The lesion burden in each subject was quantitated by MTR histographic analysis and by a computer-based method for calculating the total volume of lesions on T2-weighted images. Additionally, the CSF volume, the brain parenchymal volume, and the percentage of brain parenchymal volume were determined in all patients by using this method and were compared with measurements in eight control subjects. RESULTS: Significant loss of parenchymal volume was seen in patients with MS as determined by increased CSF volume and decreased percentage of brain parenchymal volume relative to that in age-matched control subjects. An inverse correlation was observed between the peak height of the MTR histogram and T2 lesion volume. T2 lesion volume corresponded positively with CSF volume and inversely with percentage of brain parenchymal volume. The peak height of the MTR histogram corresponded positively with percentage of brain parenchymal volume and inversely with CSF volume. CONCLUSION: MS patients sustain a significant loss of parenchymal volume (atrophy), which corresponds strongly with increasing lesion burden. T2 lesion volume and peak height of the MTR histogram show good correlation, and the peak height of the MTR histogram shows a superior correlation with measures of brain atrophy as compared with measurements of T2 lesion volume, suggesting that the MTR histogram may be a better indicator of global disease burden than is T2 lesion volume.

Adult↗