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Biomedical subjects

B L Holman

Publications and source records attributed to B L Holman.

At least 55 records · Page 3Linked to original sources
PubMed1994

Brain single-photon emission computed tomography.

Single-photon emission computed tomography (SPECT) provides cost-effective information on regional cerebral perfusion and, indirectly, on regional cerebral metabolism. Its ease of use facilitates the application of SPECT in clinical neurology. SPECT is emerging as a useful tool for the management of patients with stroke, epilepsy, recurrent brain neoplasms, and some forms of dementia. The applications being investigated, such as in vivo receptor labeling for benzodiazepines, serotonin, dopamine, and muscarinic receptors, may expand the clinical usefulness of this technique in the future.

Brain Death↗
PubMed1994

Detection of intracranial abnormalities in patients with chronic fatigue syndrome: comparison of MR imaging and SPECT.

OBJECTIVE: Chronic fatigue syndrome is a recently characterized condition of unknown origin that is manifested by fatigue, flulike complaints, and neurologic signs and symptoms, including persistent headache, impaired cognitive abilities, mood disorders, and sensorimotor disturbances. This syndrome can be difficult to diagnose clinically or by standard neuroradiologic tests. We performed MR imaging and single-photon emission computed tomography (SPECT) in patients with chronic fatigue syndrome to compare the usefulness of functional and anatomic imaging in the detection of intracranial abnormalities. SUBJECTS AND METHODS: Sixteen patients who fulfilled the Centers for Disease Control, British, and/or Australian criteria for chronic fatigue syndrome had MR and SPECT examinations within a 10-week period. Axial MR and SPECT scans were analyzed as to the number and location of focal abnormalities by using analysis of variance with the Student-Newman-Keuls option. MR imaging findings in patients with chronic fatigue syndrome were compared with those in 15 age-matched control subjects, and SPECT findings in the patients with chronic fatigue syndrome were compared with those in 14 age-matched control subjects by using Fisher's exact test. The findings on MR and SPECT scans in the same patients were compared by using the Wilcoxon matched-pairs signed-ranks test. RESULTS: MR abnormalities consisted of foci of T2-bright signal in the periventricular and subcortical white matter and in the centrum semiovale; there were 2.06 foci per patient, vs 0.80 foci per control subject. MR abnormalities were present in eight (50%) of 16 patients, compared with three (20%) of 15 age-matched control subjects. Neither of these differences reached significance, although the power of the study to detect differences between groups was small. Patients with chronic fatigue syndrome had significantly more defects throughout the cerebral cortex on SPECT scans than did normal subjects (7.31 vs 0.43 defects per subject, p < .001). SPECT abnormalities were present in 13 (81%) of 16 patients, vs three (21%) of 14 control subjects (p < .01). SPECT scans showed significantly more abnormalities than did MR scans in patients with chronic fatigue syndrome (p < .025). In the few patients who had repeat SPECT and MR studies, the number of SPECT abnormalities appeared to correlate with clinical status, whereas MR changes were irreversible. CONCLUSION: SPECT abnormalities occur more frequently and in greater numbers than MR abnormalities do in patients with chronic fatigue syndrome. SPECT may prove to be useful in following the clinical progress of patients with this syndrome.

Adult↗
PubMed1994

SPECT imaging of the brain: comparison of findings in patients with chronic fatigue syndrome, AIDS dementia complex, and major unipolar depression.

OBJECTIVE: Chronic fatigue syndrome is an illness of unknown origin that begins abruptly with a flulike state and has symptoms suggesting both a chronic viral encephalitis and an affective disorder. We compared single-photon emission computed tomography (SPECT) scans of patients with chronic fatigue syndrome with those of patients with AIDS dementia complex and unipolar depression. SUBJECTS AND METHODS: We used 99mTc-hexamethylpropyleneamine oxime to examine 45 patients with chronic fatigue syndrome, 27 patients with AIDS dementia complex, and 14 patients with major unipolar depression. Scans of 38 healthy persons were used as controls. Comparison of regional defects between groups, as well as midcerebral uptake indexes (an objective measure of global radionuclide uptake), was performed by using analysis of variance with the Student-Newman-Keuls option. Correlation between the number of regional defects and the midcerebral uptake index was determined by using the Spearman rank-correlation test. RESULTS: Patients with AIDS dementia complex had the largest number of defects (9.15 per patient) and healthy patients had the fewest defects (1.66 per patient). Patients with chronic fatigue syndrome and depression had similar numbers of defects per patient (6.53 and 6.43, respectively). In all groups, defects were located predominantly in the frontal and temporal lobes. The midcerebral uptake index was found to be significantly lower (p < .002) in the patients with chronic fatigue syndrome (.667) and patients with AIDS dementia complex (.650) than in patients with major depression (.731) or healthy control subjects (.716). Also, a significant negative correlation was found between the number of defects and midcerebral uptake index in patients with chronic fatigue syndrome and AIDS dementia complex, but not in depressed patients or control subjects. CONCLUSION: These findings are consistent with the hypothesis that chronic fatigue syndrome may be due to a chronic viral encephalitis; clinical similarities between chronic fatigue syndrome and depression may be due to a similar distribution and number of defects in the two disorders.

AIDS Dementia Complex↗
PubMed1994

Gender differences in cerebral perfusion in cocaine abuse: technetium-99m-HMPAO SPECT study of drug-abusing women.

UNLABELLED: Cocaine abuse continues to be a major public health concern, with a variety of medical and neurologic sequelae. Previous studies have demonstrated abnormalities in cerebral perfusion in chronic cocaine abusers and after acute administration of cocaine. Although women are becoming increasingly represented among drug abusers, few studies have included women. To the authors' knowledge, none has compared cerebral perfusion in asymptomatic women with that in men. METHODS: The cerebral perfusion of 13 cocaine-dependent women, 4 of whom were also heroin dependent, was studied with 99mTc hexamethylpropyleneamine oxime (HMPAO) SPECT. These women were compared with 13 cocaine-dependent men and 26 healthy control subjects. Structural brain lesions and neurologic abnormalities were excluded by MRI and neurologic evaluation. Perfusion studies were interpreted in a standardized fashion by reviewers blinded to clinical information. RESULTS: It was found that cocaine-dependent women were much less likely to have abnormal study findings than cocaine-dependent men (p = 0.003) and were indistinguishable from normal women (p = 1.0). However, the results in both women and men who concurrently used heroin plus cocaine were all abnormal. Perfusion abnormalities tended to be located in anterior brain structures, such as the frontal and temporal cortex and the basal ganglia. CONCLUSION: These data suggest that cocaine-dependent women have fewer abnormalities in cerebral perfusion than cocaine-dependent men, but that concurrent abuse of heroin and cocaine is associated with more perfusion abnormalities in both sexes.

Adult↗
PubMed1994

Hyperperfusion of ictal seizure focus demonstrated by MR perfusion imaging.

MR using a susceptibility-weighted sequence and dynamic contrast enhancement with gadolinium demonstrated relative hyperperfusion of the right temporoparietal cortex in a patient in focal status epilepticus. A single-photon emission CT (SPECT) scan also demonstrated hyperperfusion of the right temporoparietal cortex. Perfusion MR, SPECT, and electroencephalogram normalized when the seizures ended.

Adult↗
PubMed1994

Early and delayed brain SPECT with technetium-99m-ECD and iodine-123-IMP in subacute strokes.

UNLABELLED: The brain distribution of 99mTc-ECD versus 123I-IMP was compared in patients with subacute stroke in order to compare diagnostic accuracy. METHODS: A total of 25 patients with subacute stroke underwent early and delayed SPECT imaging with 99mTc-ECD and 123I-IMP. Washout of 99mTc-ECD was calculated and a differential percentage of activity (DPA) of ischemic versus normal zones was assessed. Images were analyzed twice by five independent observers. RESULTS: Technetium-99m-ECD clearance was 12.5% from the whole brain during early imaging. Ischemic parietal zones had higher clearance than normal parietal zones. Technetium-99m-ECD images showed larger differences between abnormal and normal brain activity than 123I-IMP images. Detection accuracy was slightly, but not significantly, higher for 99mTc-ECD and 123I-IMP (sensitivity: 73.8% as 66.6%; specificity: 81.7% as 81.6%). Reproducibility among observers was similar for 99mTc-ECD and early 123I-IMP. CONCLUSION: Technetium-99m-ECD demonstrates high diagnostic accuracy during subacute stroke, similar to 123I-IMP, but with more intense, better delineation of the perfusion defects.

Adult↗
PubMed1994

A neural network classifier for cerebral perfusion imaging.

UNLABELLED: Artificial neural networks have been applied to a variety of pattern recognition tasks in medical imaging and have been shown to be a powerful classification tool. The potential usefulness to discriminate normal from abnormal cerebral perfusion patterns was investigated. METHODS: Cerebral perfusion imaging with 99mTc-labeled hexamethylpropyleneimine oxime was performed on 52 normal control subjects, 29 patients with clinically diagnosed Alzheimer's disease (AD) and 25 patients with chronic cocaine polydrug abuse. Each study was registered and scaled to a common anatomic coordinate system, yielding 120 standardized cortical regions. A back-propagation neural network classifier based on regional perfusion was used to classify normal and abnormal perfusion patterns. The neural network was trained to discriminate patients with AD from age-matched normal controls and cocaine polydrug abuse patients from normal controls. The performance of the neural network in these two tasks was evaluated quantitatively by receiver operating characteristic (ROC) analysis using cross-validation. RESULTS: For patients with AD, the area under the ROC curve was 0.93 +/- 0.04. When testing with the cocaine polydrug abuser data, the area under the ROC curve was 0.89 +/- 0.04. CONCLUSION: Neural networks provide a potentially useful tool in the decision-making task to discriminate patients with AD and cocaine abuse from normal controls.

Adult↗
PubMed1993

Thallium-201 technetium-99m HMPAO single-photon emission computed tomography (SPECT) imaging for guiding stereotactic craniotomies in heavily irradiated malignant glioma patients.

SPECT scanning with Tl-201 and Tc-99m offers a unique, inexpensive functional imaging modality to combine with CT stereotactic craniotomy for guiding resection of necrosis and/or tumour in patients treated with escalated doses of radiation (> 6000 cGy) by either brachytherapy or radiosurgery. Thirty-two cases were analyzed, with a detailed description of the imaging and operative techniques.

Astrocytoma↗
PubMed1993

Cerebral blood flow in patients with dementia of Alzheimer's type.

In the normal brain as well as in Alzheimer's disease (AD), regional cerebral blood flow (CBF) is coupled to metabolic demand and, therefore, changes in CBF reflect variations in neuronal metabolism. The use of radionuclide techniques, such as positron emission tomography (PET) and single photon emission computed tomography (SPECT), provides an accurate assessment of regional functional activity, i.e., CBF and metabolism, and could be very helpful for the differential diagnosis of AD. This disease is characterized by a decrease in global CBF and metabolism. When found, a symmetric bi-parieto-temporal CBF reduction is highly diagnostic for AD, despite the fact that a similar CBF pattern could also be observed in other types of dementia. Many AD patients with parieto-temporal flow reduction also have a diffuse flow reduction in the frontal cortical areas, particularly in advanced stages of the disease. Lateral CBF asymmetry is also very frequent; speech disorders are highly characteristic of left-sided flow reduction, while visuospatial apraxia is dominating in the right-sided cases. In advanced and severe cases of AD, CBF and metabolism tend to be more uniformly reduced throughout the cortex, sparing only the primary visual and sensory-motor cortices. PET and SPECT measurement of brain perfusion and metabolism has added a new dimension to the knowledge of dementia disorders, with a better differential diagnosis between AD and other forms of dementia. The correlation with neuropsychological data has also given new insight into the disease.

Aging↗
PubMed1993

Tc-99m HMPAO brain perfusion SPECT in acute aphasia. Correlation with clinical and structural findings.

Tc-99m hexamethylpropylene amineoxime (HMPAO) brain perfusion SPECT was correlated with CT, MRI, and clinical findings in 17 patients with acute and subacute aphasia to determine its diagnostic potential in the early phases of stroke-associated language dysfunction. SPECT was performed using a dedicated brain imaging system after intravenous injection of 20 mCi (740 MBq) of Tc-99m HMPAO. Transaxial and three-dimensional surface rendered images were evaluated visually, and perfusion defects were correlated with CT, MRI, and a standard battery of clinical tests for aphasia. Clinical examination was insufficient for anatomic localization of aphasia in more than 40% of patients. CT exams were normal in 5 patients, although SPECT demonstrated perfusion defects in all 17. Nonfluent aphasia was present in only 6 of 10 patients with perfusion defects in Broca's area and fluent aphasia was present in only 5 of 10 patients with lesions in Wernicke's area. Auditory comprehension defect was associated with perfusion defects in the inferior parietal region in 9 of 12 patients (P = 0.05); reading and writing abnormalities were associated with perfusion defects in the posterior frontal, superior and inferior parietal cortex, and superior temporal gyri, and repetition deficit was associated with defects involving the inferior parietal cortex, the supramarginal and angular gyri, and the ipsilateral thalamus in 8 of 11 patients (P < 0.05). Brain perfusion SPECT should be included in the initial evaluation of aphasic patients, because clinical tests of aphasia and morphological imaging have limited value for accurately determining the extent and location of functional deficits.

Acute Disease↗
PubMed1993

Quantitative brain SPECT in Alzheimer's disease and normal aging.

To improve the diagnostic utility of brain single-photon emission computed tomography (SPECT) in Alzheimer's disease (AD), we have developed and evaluated an objective method of differentiating patients and healthy elderly controls using a quantitative image analysis protocol. HMPAO-SPECT image datasets from 29 patients with probable AD and 78 age-matched controls were registered to a common anatomic frame of reference. Activity levels within 120 standardized cortical volumes were determined by an automated procedure. Subjects were classified into normal and AD groups by quadratic discriminant analysis using two features: global average activity level and average normalized activity levels within the two clusters of standardized volumes identified as most significantly different in AD by analysis of covariance. The classification used split-half replication to ensure valid results. Classification performance quantified by the area under a binormal ROC curve fitted to the data was 0.923 +/- 0.036; at a threshold likelihood ratio of 1, the sample sensitivity was 91% and specificity was 86%. We conclude that quantitative SPECT accurately distinguishes AD patients from elderly controls.

Aged↗