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Satoshi Minoshima

Publications and source records attributed to Satoshi Minoshima.

33 records · Page 2Linked to original sources
PubMed2004

18F-FDG PET of gliomas at delayed intervals: improved distinction between tumor and normal gray matter.

UNLABELLED: We hypothesized that delineation of gliomas from gray matter with 18F-FDG PET could be improved by extending the interval between 18F-FDG administration and PET data acquisition. The purposes of this study were, first, to analyze standard and delayed 18F-FDG PET images visually and quantitatively to determine whether definition of tumor improved at later imaging times and, second, to investigate the dynamics of model-derived kinetic rate constants, particularly k4. METHODS: Nineteen adult patients with supratentorial gliomas were imaged from 0 to 90 min and once or twice later at 180-480 min after injection. In 15 patients, arterial sampling provided the early input function. Venous sampling provided the remaining curve to the end of the imaging sequence. Standardized uptake value (SUV) was calculated as tissue concentration of tracer per injected tracer dose per body weight. Ratios of tumor SUV relative to the SUV of gray matter, brain (including gray and white matter), or white matter were calculated at each imaging time point. Dynamic image data from tumor, gray matter, brain, or white matter were analyzed using a 2-compartment, 4-parameter model applied for the entire duration of imaging, in which delay, K1, distribution volume, k3, and k4 were optimized using a nonlinear optimization method. Parameter estimation for each region included both an early subset of data from a conventional dynamic imaging period (0-60 min) and the full, extended dataset for each region. RESULTS: In 12 of the 19 patients, visual analysis showed that the delayed images better distinguished the high uptake in tumors relative to uptake in gray matter. SUV comparisons also showed greater uptake in the tumors than in gray matter, brain, or white matter at the delayed times. The estimated k4 values for tumors were not significantly different from those for gray matter in early imaging analysis but were lower (P < 0.01) using the extended-time data. CONCLUSION: The kinetic parameter results confirm the visual and SUV interpretation that tumor enhancement is greater than enhancement of surrounding brain regions at later imaging times, consistent with a greater effect of FDG-6-phosphate degradation on normal brain relative to glioma.

Adult↗
PubMed2004

18F-FDG kinetics in locally advanced breast cancer: correlation with tumor blood flow and changes in response to neoadjuvant chemotherapy.

UNLABELLED: The aim of this study was to characterize the biologic response of locally advanced breast cancer (LABC) to chemotherapy using (15)O-water-derived blood flow measurements and (18)F-FDG-derived glucose metabolism rate parameters. METHODS: Thirty-five LABC patients underwent PET with (15)O-water and (18)F-FDG before neoadjuvant chemotherapy and 2 mo after the initiation of treatment. Kinetic analysis for (15)O-water was performed using a single tissue compartment model to calculate blood flow; a 2-tissue compartment model was used to estimate (18)F-FDG rate parameters K(1), k(2), k(3), and the flux constant, K(i). Correlations and ratios between blood flow and (18)F-FDG rate parameters were calculated and compared with pathologic tumor response. RESULTS: Although blood flow and (18)F-FDG transport (K(1)) were correlated before chemotherapy, there was relatively poor correlation between blood flow and the phosphorylation constant (k(3)) or the overall (18)F-FDG flux (K(i)). Blood flow and (18)F-FDG flux were more closely matched after chemotherapy, with changes in k(3) accounting for the increased correlation. These findings were consistent with a decline in both the K(i)/flow and k(3)/flow ratios with therapy. The ratio of (18)F-FDG flux to transport (K(i)/K(1)) after 2 mo of chemotherapy was predictive of ultimate response. CONCLUSION: The pattern of tumor glucose metabolism in LABC, as reflected by analysis of (18)F-FDG rate parameters, changes after therapy, even in patients with modest clinical responses. This may indicate a change in tumor "metabolic phenotype" in response to treatment. A low ratio of glucose metabolism (reflected by K(i)) to glucose delivery (reflected by K(1) and blood flow) after therapy is associated with a favorable response. Further work is needed to understand the tumor biology underlying these findings.

Antineoplastic Agents↗
PubMed2003

Cerebral metabolic changes accompanying conversion of mild cognitive impairment into Alzheimer's disease: a PET follow-up study.

A high percentage of patients with mild cognitive impairment (MCI) develop clinical dementia of the Alzheimer type (AD) within 1 year. The aim of this longitudinal study was to identify characteristic patterns of cerebral metabolism at baseline in patients converting from MCI to AD, and to evaluate the changes in these patterns over time. Baseline and follow-up examinations after 1 year were performed in 22 MCI patients (12 males, 10 females, aged 69.8+/-5.8 years); these examinations included neuropsychological testing, structural cranial magnetic resonance imaging and fluorine-18 fluorodeoxyglucose positron emission tomography (PET) evaluation of relative cerebral glucose metabolic rate (rCMRglc). Individual PET scans were stereotactically normalised with NEUROSTAT software (Univ. of Michigan, Ann Arbor, USA). Subsequently, statistical comparison of PET data with an age-matched healthy control population and between patient subgroups was performed using SPM 99 (Wellcome Dept. of Neuroimaging Sciences, London, UK). After 1 year, eight patients (36%) had developed probable AD (referred to as MCI(AD)), whereas 12 (55%) were still classified as having stable MCI (referred to as MCI(MCI)). Compared with the healthy control group, a reduced rCMRglc in AD-typical regions, including the temporoparietal and posterior cingulate cortex, was detected at baseline in patients with MCI(AD). Abnormalities in the posterior cingulate cortex reached significance even in comparison with the MCI(MCI) group. After 1 year, MCI(AD) patients demonstrated an additional bilateral reduction of rCMRglc in prefrontal areas, along with a further progression of the abnormalities in the parietal and posterior cingulate cortex. No such changes were observed in the MCI(MCI) group. In patients with MCI, characteristic cerebral metabolic differences can be delineated at the time of initial presentation, which helps to define prognostic subgroups. A newly emerging reduction of rCMRglc in prefrontal cortical areas is associated with the transition from MCI to AD.

Aged↗
PubMed2003

Prediction of hyperperfusion after carotid endarterectomy by brain SPECT analysis with semiquantitative statistical mapping method.

BACKGROUND AND PURPOSE: Hyperperfusion syndrome is a rare but disastrous complication after carotid endarterectomy (CEA). The aim of this study was to investigate the relationship between preoperative cerebral blood flow (CBF) abnormalities and postoperative hyperperfusion through the use of statistical brain mapping analysis. METHODS: For 41 patients with unilateral carotid stenosis >or=70%, CBF and cerebral vasoreactivity (CVR) were investigated with resting and acetazolamide-challenge single photon emission CT before CEA. CBF 1 day after CEA was also measured. Three-dimensional stereotactic surface projection (3D-SSP) analysis of CBF changes was performed by use of a control database of 20 subjects. RESULTS: Patients with reduced CVR (CVR <10%, n=15) were categorized into 2 groups based on the severity of CBF reduction relative to the control database by 3D-SSP analysis without normalization: type I (ipsilateral CBF decrease <20%, n=8) and type II (ipsilateral CBF decrease >or=20%, n=7). With thalamic normalization, the patients were also categorized into 2 groups: type A (ipsilateral Z score 2, n=5). Severe CBF reduction (>or=20% or Z score >2) was significantly associated with postoperative hyperperfusion (CBF increase >or=100%). However, 3D-SSP with thalamic normalization (Z score) demonstrated a higher predictive value (80%) and specificity (91%) for hyperperfusion than 3D-SSP without normalization (percent reduction) (57% and 73%, respectively). No patients with normal CVR (CVR >or=10%, n=26) demonstrated postoperative hyperperfusion. CONCLUSIONS: Objective evaluation of abnormalities of CBF and CVR with 3D-SSP could identify patients at risk for postoperative hyperperfusion.

Acetazolamide↗
PubMed2003

Diminished striatal [123I]iodobenzovesamicol binding in idiopathic cervical dystonia.

Striatal dysfunction is thought to underlie many dystonias. We used [(123)I]iodobenzovesamicol single-photon emission computed tomography imaging to determine the density of cholinergic terminals in the striatum and other brain regions in 13 subjects with idiopathic cervical dystonia. Striatal [(131)I]iodobenzovesamicol binding was reduced. These results support a role for striatal dysfunction in idiopathic dystonias and suggest diminished striatal cholinergic interneuron density in cervical dystonia.

Adult↗
PubMed2003

Insights into the pathophysiology of neuropathic pain through functional brain imaging.

We present here an example case of neuropathic pain with heat allodynia as a major symptom to illustrate how the functional imaging of pain may provide new insights into the pathophysiology of painful sensory disorders. Tissue injury of almost any kind, but especially peripheral or central neural tissue injury, can lead to long-lasting spinal and supraspinal re-organization that includes the forebrain. These forebrain changes may be adaptive and facilitate functional recovery, or they may be maladaptive, preventing or prolonging the painful condition, and interfering with treatment. In an experimental model of heat allodynia, we used functional brain imaging to show that: (1) the forebrain activity during heat allodynia is different from that during normal heat pain, and (2) during heat allodynia, specific cortical areas, specifically the dorsolateral prefrontal cortex, can attenuate specific components of the pain experience, such as affect, by reducing the functional connectivity of subcortical pathways. The forebrain of patients with chronic neuropathic pain may undergo pathologically induced changes that can impair the clinical response to all forms of treatment. Functional imaging, including PET, fMRI, and neurophysiological techniques, should help identify brain mechanisms that are critical targets for more effective and more specific treatments for chronic, neuropathic pain.

Adult↗
PubMed2003

Imaging Alzheimer's disease: clinical applications.

Extensive PET imaging research on AD has been conducted since PET scanners became available in the early 1980s. PET imaging using FDG, now commercially available, can detect early metabolic changes in AD and differential metabolic features of various dementing disorders. Image analysis techniques have also advanced in the field of functional brain imaging and permit accurate and consistent scan interpretation. PET studies that involve autopsy-confirmed cases suggest that the PET diagnosis of AD is no worse or may even be better than clinical diagnosis. Limited prospective studies demonstrated the effects of PET imaging in dementia management, which precludes the approval of FDG PET for more widespread, reimbursable use. Further evidence for the efficacy of PET imaging through well-organized clinical studies, as well as continuing efforts in technologic development and basic research to characterize functional alterations in dementing disorders in living patients, are equally important to achieve the goal of better dementia care.

Alzheimer Disease↗
PubMed2003

Determination of kinetic rate constants for 2-[18F]fluoro-2-deoxy-D-glucose and partition coefficient of water in conscious macaques and alterations in aging or anesthesia examined on parametric images with an anatomic standardization technique.

Kinetic rate constants for 2-[18F]fluoro-2-deoxy-d-glucose (FDG) and the tissue-blood partition coefficient of water were determined using dynamic positron emission tomography in conscious macaques, and alterations in these parameters in aging or anesthesia were also examined. The parameters were estimated on a pixel-by-pixel basis using an anatomic standardization technique; group differences were then examined on the parametric images from the young, aged, and anesthesia groups. For the conscious condition, seven young and seven aged male rhesus macaques were used; six young male rhesus macaques were used for the isoflurane anesthesia condition. H2 15O and FDG were used as tracers. The kinetic parameters were estimated by a nonlinear least-square fitting procedure with compartment models including terms for the cerebral blood volume (CBV) and time delay of the input function. Cerebral blood flow (CBF) and cerebral metabolic rate of glucose (CMRglc) were also calculated from the estimated parameters. In the aged group, glucose phosphorylation was decreased more than glucose transport, and the occipital cortex was the most affected region where reduction in CBV, CMRglc, and CBF were also observed. In the anesthesia group, glucose transport was decreased; however, glucose phosphorylation was not affected except for the occipital pole. The occipital cortex was also the most affected region. The tissue-blood partition coefficient of water was decreased globally.

Aging↗
PubMed2002

A unique representation of heat allodynia in the human brain.

Skin inflammation causes innocuous heat to become painful. This condition, called heat allodynia, is a common feature of pathological pain states. Here, we show that heat allodynia is functionally and neuroanatomically distinct from normal heat pain. We subtracted positron emission tomography scans obtained during painful heating of normal skin from scans during equally intense but normally innocuous heating of capsaicin-treated skin. This comparison reveals the specific activation of a medial thalamic pathway to the frontal lobe during heat allodynia. The results suggest that different central pathways mediate the intensity and certain qualitative aspects of pain. In making this differentiation, the brain recognizes unique physiological features of different painful conditions, thus permitting adaptive responses to different pain states.

Adult↗
PubMed2002

Prominent hypometabolism of the right temporoparietal and frontal cortex in two left-handed patients with primary progressive aphasia.

Primary progressive aphasia (PPA) is characterized by progressive deterioration of language function with relative preservation of other cognitive functions. Previous studies based on neuroimaging and histology point to predominantly left temporal pathology in PPA patients. Here we report two left-handed subjects with typical symptoms of the nonfluent form of PPA in whom 18F-FDG PET revealed an asymmetric right-hemispheric pattern of reduced glucose metabolism in the frontal and temporoparietal cortex. These findings support the hypothesis that PPA can be considered as a symptom complex rather than a disease entity.

Aged↗
PubMed2002

Neuroimaging in dementia with Lewy bodies: metabolism, neurochemistry, and morphology.

Dementia with Lewy bodies (DLB) is recognized as one of the most common forms of neurodegenerative dementia. Neuroimaging contributes to a better understanding of the pathophysiology of DLB by examining alterations in brain metabolism, neurochemisty, and morphology in living patients. Neuroimaging can provide objective and quantifiable antemortem markers for the presence of and the progression of DLB and permits differentiation from other dementias. This article reviews current neuroimaging findings in DLB with particular attention to occipital hypometabolism, dopaminergic and cholinergic deficits, and medial temporal lobe atrophy as measured by positron emission tomography, single-photon emission computed tomography, and magnetic resonance imaging.

Aged↗
PubMedDate not supplied

Transfection of neuroprogenitor cells with iron nanoparticles for magnetic resonance imaging tracking: cell viability, differentiation, and intracellular localization.

PURPOSE: Magnetic resonance imaging (MRI) can track labeled cells in the brain. The use of hemagglutinating virus of Japan envelopes (HVJ-Es) to effectively introduce the contrast agent to neural progenitor cells (NPCs) is limited to date despite their high NPC affinity. PROCEDURES: HVJ-Es and Lipofectamine 2000 were compared as transfection vehicles of superparamagnetic iron oxide (SPIO). Labeled NPCs were examined for iron content, MRI signal change, and fundamental cell characteristics. Prussian Blue staining was used after differentiation to determine SPIO localization. RESULTS: HVJ-Es transfected up to 12.5 +/- 8.8 times more SPIO into NPCs. HVJ-Es do not affect cell viability or differentiation capability. Superparamagnetic iron oxide was disseminated in both the soma and neurites. CONCLUSIONS: These findings indicate that HVJ-Es are an effective vehicle for SPIO transfection of NPCs. The intracellular localization after differentiation raises the question as to the capability of MRI to distinguish cell migration from axonal or dendritic growth in vivo.

Animals↗
PubMedDate not supplied

Regional brain activation due to pharmacologically induced adrenergic interoceptive stimulation in humans.

OBJECTIVE: Identifying the brain regions associated with visceral sensory activation and awareness (interoception) was a neglected area of neural science until quite recently despite being essential to a comprehensive understanding of psychosomatic processes, baroreception, and higher brain functions such as fear and anxiety, other emotions, and pain. METHODS: In this study regional changes in the cerebral metabolic rate for glucose were determined with positron emission tomography in response to cardiovascular-respiratory activation induced in healthy humans by beta-adrenergic stimulation produced with intravenous isoproterenol, which acts predominantly in the periphery because of minimal transport across the blood-brain barrier. RESULTS: Interoceptive activation raised heart rate to approximately 120 beats per minute, produced somatic and to a lesser extent psychological symptoms, and significantly increased cerebral glucose metabolism in the left primary somatosensory cortex and medial portion of the cingulate gyrus; right insular cortex showed a trend toward an increase that was significant in homogeneous subgroups of right-handed or female subjects. CONCLUSIONS: These results demonstrate the involvement of specific brain regions as well as hemispheric laterality of function in visceral perception, and they suggest that during emotional reactions involving changes in visceral organ function, activation of some of the brain regions observed could be due specifically to interoceptive processes.

Adrenergic beta-Agonists↗