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Biomedical subjects

J M Mountz

Publications and source records attributed to J M Mountz.

At least 37 records · Page 2Linked to original sources
PubMed1998

Postinfectious cerebellitis: clinical significance of Tc-99m HMPAO brain SPECT compared with MRI.

PURPOSE: We compared Tc-99m HMPAO brain SPECT and MRI with the clinical findings in a case of a 14-year-old boy with post-infectious cerebellitis. RESULTS: Tc-99m HMPAO brain SPECT scan showed marked reduction in perfusion to the left anterior lobe, left lateral hemisphere, and left posterior lobe of the cerebellum. The MRI showed a limited region of abnormal signal in the mid posterior left cerebellar hemisphere. Since the patient's overall neurological deficit was characterized by ataxia, nystagmus, head and body titubation, dysmetria, dysdiadochokinesia, loss of normal check, and rebound testing attributed to the involvement of the anterior, lateral, and posterior lobes of the left cerebellar hemisphere, the Tc-99m HMPAO brain SPECT finding correlated better with the extent of functional neurological deficits. CONCLUSION: Tc-99m HMPAO brain SPECT may better assess cerebellar signs and symptoms in cerebellitis since the blood flow abnormalities correlated with dysfunction of the cerebellum, whereas the MRI abnormalities did not encompass the scope of the neurological deficits.

Adolescent↗
PubMed1998

Familial painful restless legs syndrome correlates with pain dependent variation of blood flow to the caudate, thalamus, and anterior cingulate gyrus.

To understand the relationship of caudate, thalamic, and anterior cingulate perfusion to pain states, we investigated familial restless legs syndrome in a father and daughter during the state of pain induced by immobility using semiquantitative regional cerebral blood flow (rCBF) brain single photon emission computed tomography (SPECT). The father underwent 4 brain SPECT scans using the rCBF tracer 99mTc-HMPAO several weeks apart, at different pain levels and after treatment with L-dopa. Caudate, thalamic, and anterior cingulate rCBF indices were measured. The caudate nuclei showed a 13% reduction in rCBF with increasing pain. The thalami and anterior cingulate showed a 7 and 6.6% increase in rCBF, respectively, with increasing pain. Compared to normal controls at rest, there was a decrease in caudate rCBF by 13% and an increase in thalamic rCBF by 3%. Linear regression for the caudate nuclei revealed a significant reduction in rCBF (p < 0.05), as pain increased. The daughter underwent an identical rCBF brain SPECT scan procedure at a high pain level induced by immobilization. Her scan showed a 12% reduction in caudate rCBF and a 1.2% increase in the anterior cingulate rCBF compared to healthy controls. The study supports the association between pain and decreased regional cerebral blood flow to the caudate nucleus as reported in fibromyalgia syndrome. There is increase in anterior cingulate rCBF with increasing pain. Our findings also corroborate that there is increased thalamic rCBF with pain stimulation.

Adult↗
PubMed1997

Thalamic thought disorder: on being "a bit addled".

Humans can generate and maintain relatively coherent trains of thought in natural discourse. The neural mediation of this ability and the phenomenology of its breakdown are not well understood. We report a case of a woman with paramedian thalamic strokes involving the mammillothalamic tract, intralaminar nuclei, parts of the dorsomedial and ventral lateral nuclei bilaterally. She presented with a dense amnesia and confusion typical of the syndrome of bilateral paramedian thalamic infarcts. Her Tc-99m HMPAO brain SPECT scan showed decreased thalamic and basal ganglia blood flow. General diminution of cerebral blood flow and areas of further diminution in the right frontal, left temporal and left temporoparietal regions were also observed. Although her amnesia was characteristic of diencephalic amnesia, her most striking clinical feature was a bizarre, disconnected and at times incoherent speech output. Analysis of her speech revealed relatively preserved lexical and morpho-syntactic linguistic production. By contrast, analysis of the macrostructure of her discourse revealed frequent unpredictable topic shifts that were completely unconstrained by contextual factors. Many of her shifts were intrusions from previous topics. We interpret her severely disordered speech output as representing the surface manifestations of a thought disorder (rather than as a language disorder per se) characterized by an inability to maintain and appropriately shift themes that normally guide discourse. Median and intralaminar thalamic nuclei appear to be critical for the neurophysiologic regulation of thalamocortical and striatocortical circuits, which in turn may be critical for the functional regulation of contextually appropriate transitions of thought.

Aged↗
PubMed1997

A semiquantitative cortical circumferential normalization method for clinical evaluation of rCBF brain SPECT.

The authors studied 33 normal patients who ranged in age from 8 to 71 years to establish a normative data base for young-age, middle-age, and older-age subjects using a computer automated semi-quantitative cortical annular region of interest (ROI) method. The data were grouped to obtain a "young age-range" normative data base of mean age +/- 1 S.D. = 13.1 +/- 4.8 years (seven subjects with an age range of 6 to 20 years); a "middle age-range" normative data base of mean age +/- 1 S.D. = 39 +/- 2.7 years (12 subjects with an age range of 35 to 43 years); and an "older age-range" normative data base of mean age +/- 1 S.D. = 59.7 +/- 5.8 years (14 subjects with an age range of 55 to 71 years). Normative values were obtained for brain level parallel to and positioned at 3.5, 5.5, and 7.5 cm above the canthomeatal (CM) line. The results show that the average global rCBF indices (defined as cortical/cerebellar ratios) for the young age-range group were 0.98, 0.99, 1.07; middle age-range group were 0.84, 0.86, and 0.88; and older age-range group were 0.86, 0.87 and 0.87 for CM + 3.5 cm, CM + 5.5 cm, and CM + 7.5 cm, respectively. In routine clinical studies, on more then 2,000 Tc-99m HMPAO brain SPECT scans, the authors have employed this semi-quantitative cortical circumferential normalization method of analysis to accurately calculate indices representing cortical blood flow values. This method also allows efficient comparison of individual patient values to age-range matched normal control groups to assist in disease diagnosis.

Adolescent↗
PubMed1997

Regional stability of cerebral blood flow measured by repeated technetium-99m-HMPAO SPECT: implications for the study of state-dependent change.

UNLABELLED: The replicability of resting state rCBF has implications for the analysis of cerebral activation protocols and the interpretation of rCBF in disease states. This study examined the stability of rCBF as measured by two resting state 99mTc-HMPAO brain SPECT scans with an emphasis on examining the contribution of specific cerebral regions to within and between subjects variance. METHODS: Nine normal, medically healthy subjects underwent two 99mTc-HMPAO brain SPECT scans under identical conditions separated by 48 hr. A reference system and semiautomated computer ROI method was used to enable accurate alignment and cortical analysis of the two scans. RESULTS: Mean within-subject difference between Scans 1 and 2 was 2.8% (range 0%-7.8%) for the 36 cortical ROIs. The mean between-subject coefficient of variation was 10% (range 7%-15%) for these ROIs. Correlation analysis of rCBF pattern replication for all slice levels yielded a highly significant overall consistency of pattern within subjects (Pearson r = 0.698, p = 0.0001). Variance component analysis revealed regional heterogeneity in between-subjects variance, with significantly greater variability found in frontal regions. The within-subject repeated measures variability was not significantly different across regions. CONCLUSION: Good within-subject 48-hr replicability indicates that individual resting state rCBF reflects fairly stable, subject-specific factors. This also justifies comparing state-dependent studies separated by a modest length of time. Although individual patterns of rCBF replicate well, the larger contribution of frontal regions to normal between-subjects variance makes evaluating the frontal effects of disease or activation more difficult.

Aged↗
PubMed1996

Tc-99m HMPAO brain SPECT scanning in Munchausen syndrome.

Regional cerebral blood flow was studied in a patient with Munchausen syndrome using high resolution Tc-99m HMPAO SPECT. The scan demonstrated marked hyperperfusion of the right hemithalamus. The cranial CT scan was normal. The abnormal right hemithalamic blood flow is discussed in relation to the hypothesized neuropathy of this disorder.

Female↗
PubMed1995

Fibromyalgia in women. Abnormalities of regional cerebral blood flow in the thalamus and the caudate nucleus are associated with low pain threshold levels.

OBJECTIVE: To determine if regional cerebral blood flow (rCBF) in the left and right hemithalami or the left and right heads of the caudate nucleus is abnormal in women with fibromyalgia (FM). METHODS: Resting-state rCBF in the hemithalami and left and right heads of the caudate nucleus of 10 untreated women with FM and 7 normal control women was measured by single-photon-emission computed tomography. Pain threshold levels at tender and control points also were assessed in both the women with FM and the controls. RESULTS: The rCBF in the left and right hemithalami and the left and right heads of the caudate nucleus was significantly lower in women with FM than in normal controls (P = 0.01, P = 0.003, P = 0.01, and P = 0.02, respectively). Compared with controls, the women with FM also were characterized by significantly lower cortical rCBF (P = 0.001) and lower pain threshold levels at both tender points (P = 0.0001) and control points (P = 0.0001). CONCLUSION: The findings of low rCBF and generalized low pain thresholds support the hypothesis that abnormal pain perception in women with FM may result from a functional abnormality within the central nervous system.

Adult↗
PubMed1995

SPECT abnormalities in generalized dystonia.

A patient with severe, generalized dystonia and 6 age range-matched controls were studied with the regional cerebral blood flow tracer technetium-99m hexamethylpropyleneamine oxime by single-photon emission computed tomography to test the hypothesis that cerebellar function is abnormal in dystonia. Analysis was performed by drawing regions of interest around the caudate head nuclei, hemithalami, deep cerebellar nuclei, and cerebellar hemicortices. The counts in each region of interest were normalized to whole brain cerebral blood flow in an identical manner for each subject. The dystonic patient had a difference in regional cerebral blood flow between the right and left deep cerebellar nuclei, increased regional cerebral blood flow in subcortical motor structures, and an abnormal relationship between right cerebellar cortical and right deep cerebellar nuclear regional cerebral blood flow. The findings in this patient provide evidence that the cerebellum may play a role in the pathophysiology of motor signs in some patients with dystonia.

Brain↗
PubMed1995

Focal cerebral blood flow change during craving for alcohol measured by SPECT.

To test the hypothesis that craving for alcohol in the alcohol-dependent individual is mediated by a limbic circuit involving the caudate nuclei, regional cerebral blood flow was measured with [99mTc]HMPAO SPECT during control and craving conditions in 9 alcohol-dependent subjects. In all subjects, blood flow in the head of the right caudate nucleus increased during the craving condition, and these blood flow increases were strongly correlated with the experimentally induced increases in craving for alcohol. These new findings suggest a functional role for the limbic striatum in the mediation of craving and impaired control over alcohol consumption.

Adult↗
PubMed1995

Functional deficits in autistic disorder: characterization by technetium-99m-HMPAO and SPECT.

UNLABELLED: Autistic disorder is an early and severe developmental disorder characterized by deficits in verbal and nonverbal language, social skills, cognitive functioning and an abnormal repertoire of behaviors. Current research, however, has failed to identify the neurobiological mechanisms that underlie autism or those cortical brain regions, if any, that are abnormal. METHODS: We examined regional cerebral blood flow (rCBF) in six young, severely autistic patients. High-resolution brain SPECT with 99mTc-HMPAO was performed while five of the six patients were under general anesthesia. The scans reflected the subjects' rCBF in their usual alert behavioral state, since the tracer was injected at least 15 min prior to anesthesia and is rapidly extracted and fixed in the brain. A computer-automated cortical region of interest (ROI) generator was used to define 12 annular cortical regions (region 1 = left frontal, clockwise to region 12 = right frontal) for count data acquisition. The ratio of average counts in each ROI to whole-slice counts for the autistic patients was compared to age-matched controls using repeated measures (splt-plot) ANOVA statistical analysis for three representative brain levels. RESULTS: In the autistic patients, cortical regions 3, 4, and 10 were abnormally low at the cortical level canthomeatal (CM) + 3.5 cm. At level CM + 5.5 cm, regions 3, 4, 5 and 10 were abnormally low, and at level CM + 7.5 cm, regions 7 and 9 were also abnormally low. These regions correspond to abnormally low rCBF values located predominately in the temporal and parietal lobes, with the left cerebral hemisphere showing greater rCBF abnormalities than the right. CONCLUSION: Our findings suggest that the temporal and parietal lobes have abnormal rCBF in autism. HMPAO brain SPECT in combination with general anesthesia is particularly useful for imaging severely noncompliant patients.

Adolescent↗
PubMed1994

A reference method for correlation of anatomic and functional brain images: validation and clinical application.

We describe a reference device that provides accurate correlation between anatomic and functional brain images. The reference device, which generates fiduciary reference points on sequential scan planes, is positioned adjacent to the canthomeatal line of the subject and held in place by a glasses-like framework anchored to the external auditory meatus. The reference system was tested on 17 subjects undergoing 99mTc hexamethylpropylene amine oxime ([99mTc]HMPAO) brain single-photon emission computed tomography (SPECT) and cranial computed tomography (CT) scans. The centers of the caudate nuclei, thalami, brain stem, and cerebellar vermis were identified independently on CT and SPECT. The average difference +/- 1 SD between structure locations (x, y, and z) on SPECT and CT were calculated as 1.86 +/- 1.5, 2.16 +/- 1.4, and 1.83 +/- 1.9 mm, respectively. The clinical application of the method is showed by coregistration of images from SPECT to MRI. An example of sequential [99mTc]HMPAO brain SPECT scan sections precisely coregistered with MRI scan sections oriented parallel to and sequentially above the canthomeatal line illustrates the correlation between regional cerebral blood flow (rCBF) tracer activity on SPECT and normal anatomic structures. Test-retest activation paradigms in brain SPECT requires precise SPECT-to-SPECT image coregistration to evaluate changes in rCBF during activation. Precisely coregistered rest, 48-hour repeat rest [99mTc]HMPAO SPECT studies are shown to illustrate the normal intrasubject variability of tracer uptake. An example of the usefulness of image coregistration for evaluation of viable residual brain tumor and its application to tumor biopsy is presented. An example of developmental abnormalities identified by [99mTc]HMPAO brain SPECT is illustrated by a case of autistic disorder. An example of image coregistration in stroke and evaluation of cerebrovascular disease with Diamox (Lederle Laboratory Division, Pearl River, NY) cerebrovasculature stress testing is presented. The usefulness in epilepsy using a protocol whereby the tracer is injected during the ictal phase of seizure is presented. We conclude that the reference system provides an accurate, rapid, and noninvasive patient-specific method for correlating brain structure with brain function.

Adolescent↗
PubMed1994

Technetium-99m-HMPAO brain SPECT evaluation of neurotoxicity due to manganese toxicity.

UNLABELLED: We performed initial and follow-up regional cerebral blood flow (rCBF) studies using 99mTc-hexamethylpropyleneamine oxime (HMPAO) SPECT on a patient with manganese-induced central nervous system (CNS) neurotoxicity. METHODS: The patient had a history of long-term exposure to manganese at the time of the first scan, while the follow-up scan was performed 9 mo after removal from the toxic environment. The patient's serum level of manganese was five- to tenfold greater than normal at the time of the initial rCBF brain SPECT scan. RESULTS: The rCBF brain SPECT scan demonstrated significantly decreased rCBF in the right caudate nucleus and both thalami. A MRI scan obtained at the same time was normal. The follow-up rCBF brain SPECT scan was normal. CONCLUSIONS: This report supports the utilization of functional rCBF brain SPECT imaging to provide objective evidence of a function CNS abnormality due to neurotoxicity at an early clinical stage. Our results emphasize that rCBF brain SPECT may provide a confirmational test to support the diagnosis of neurotoxicity in the appropriate clinical setting.

Brain↗
PubMed1993

Ictal single-photon emission computed tomography demonstrates localized epileptogenesis in cortical dysplasia.

We investigated the use of ictal single-photon emission computed tomography (SPECT) in 2 children with intractable epilepsy. Ictal scalp electroencephalographic studies failed to localize the epileptic focus and interictal data demonstrated widespread lateralized abnormalities. Ictal SPECT studies with technetium 99m-hexamethylpropyleneamineoxime demonstrated focal areas of hyperperfusion in the frontal lobes. Resection of the abnormal areas shown by SPECT was carried out despite evidence of large areas of epileptogenesis demonstrated by scalp and subdural electroencephalographic studies. Pathological material revealed cortical dysplasia. Ictal SPECT provides functional evidence for localized epileptogenesis in focal cortical dysplasia.

Cerebral Cortex↗
PubMed1993

Regional cerebral blood flow changes in stroke imaged by Tc-99m HMPAO SPECT with corresponding anatomic image comparison.

Cerebral infarction is the result of cerebrovascular insufficiency and itself creates complex changes in cerebral hemodynamics. To allow recognition of patterns of change in regional cerebral blood flow (r-CBF) caused by cerebral infarction, the authors present an atlas of Tc-99m hexamethylpropyleneamine oxime (Tc-99m HMPAO) SPECT brain scan sections for a variety of strokes demonstrating typical vascular territorial involvements and evolution of morphologic and r-CBF change. Sections from MRI or CT are shown with SPECT images of the stroke lesion for comparison of the complementary information provided by regional cerebroperfusion and by morphology. Examples of SPECT during acute, subacute, and chronic stages of stroke are provided. To illustrate the temporal evolution of stroke and accompanying changes in the "stroke penumbra," case examples of acute tissue necrosis, luxury perfusion, ischemia, and diaschisis are presented. Methods for semiquantitative analysis of morphologic versus r-CBF defect size after acute stroke are described. How brain SPECT scans conducted during Diamox initiated cerebrovascular stress tests can complement the information obtained from baseline studies and assist in the interpretation of r-CBF abnormalities is also demonstrated.

Adult↗
PubMed1993

Effect of haloperidol on measures of craving and impaired control in alcoholic subjects.

We recently proposed that alcoholics suffer from a functional defect within the basal ganglia/limbic striatum or its modulation by dopaminergic projections from the ventral tegmentum, and that inhibition of striatal output caused by the prodopaminergic effects of alcohol ingestion induces or exacerbates craving and impaired control over alcohol consumption in alcoholic individuals. To test this hypothesis, 16 subjects with a diagnosis of alcohol dependence or abuse were studied in a double-blind, placebo-controlled experiment in which the effects of the D-2 antagonist haloperidol on measures of craving and impaired control were assessed before and after administration of a priming dose of alcohol. Subjects were pretreated with 0.015-0.025 mg/kg haloperidol (experimental condition) or 2 ml normal saline (control condition), and subsequently consumed 0.4-0.6 g/kg ethanol as their preferred alcohol-containing beverage. Significant increases in subjectively rated craving for alcohol and perceived difficulty resisting additional alcohol consumption occurred following the priming dose of alcohol when subjects were pretreated with saline. In contrast, no significant changes in reported ability to resist additional alcohol occurred when subjects were pretreated with haloperidol, and reported levels of craving decreased relative to baseline following haloperidol pretreatment. Subjects also consumed about 25% less optionally available alcohol when pretreated with haloperidol than when pretreated with saline. These findings support the hypothesis that craving and impaired control are induced or exacerbated by the prodopaminergic effects of alcohol consumption.

Adult↗
PubMed1993

Ictal 99mTc HM-PAO brain single-photon emission computed tomography in electroencephalographic nonlocalizable partial seizures.

A 9-year-old child with intractable focal epilepsy was studied for possible surgical treatment. Multiple electroencephalographic studies did not localize the epileptic focus. An ictal single-photon emission computed tomography (SPECT) study with technetium 99m-hexamethylpropyleneamineoxime demonstrated a focal area of hyperperfusion. Through three-dimensional, functional to anatomical image-matching techniques, the focus was overlaid on the magnetic resonance image localizing the cortical convolution responsible for the epileptogenic focus. Subdural electroencephalographic studies performed for seizure localization and functional mapping confirmed this location. This case emphasized the usefulness of ictal SPECT scans in patients with seizures nonlocalizable by electroencephalography being evaluated for epilepsy surgery.

Child↗
PubMed1993

The ethics and safety of alcohol administration in the experimental setting to individuals who have chronic, severe alcohol problems.

There is a popular belief that the experimental administration of alcohol to individuals who have chronic, severe alcohol problems ('alcoholics') is inherently dangerous or unethical. This creates an environment in which researchers who desire to conduct a study involving the administration of alcohol to persons with severe alcohol problems must defend the relative safety and reasonableness of this practice when, in fact, scientific justification for not using this important methodologic technique in alcohol research is lacking. The primary purpose of this manuscript is to present and discuss the safety, ethical, and practical considerations of research involving administration of alcohol to subjects who have had difficulty refraining from harmful alcohol use in the natural setting. The authors also describe a study in which they monitored the short-term effects of administering 0.4-0.6 g/kg alcohol to 16 recently abstinent subjects who had chronic, severe alcohol problems. This study revealed no evidence that the administration of beverage alcohol in the experimental setting to such individuals causes an uncontrollable desire for more alcohol, precipitates immediate relapse, or creates any behavioral problems. The data also suggested that the knowledge gained from the effects of alcohol ingestion in the experimental setting might help many subjects to understand more completely their addiction or drinking behaviour. It is concluded that there is no overriding reason why alcohol cannot, with due precaution, be safely and ethically administered in the experimental setting to human subjects who suffer from alcohol problems.

Adult↗