Frontal hypoperfusion in depressed patients with dementia of Alzheimer type demonstrated on 3DSRT

Aims: Depressive symptoms are common in patients with dementia of Alzheimer type (DAT) and contribute to clinical morbidity. Previous studies have suggested that hypoperfusion in the prefrontal cortex and anterior cingulate gyrus are involved in the pathophysiology of depression in DAT. Using 3‐D stereotactic region of interest (ROI) template (3DSRT), fully automated ROI analysis software, the purpose of the present study was to investigate the relationship between depressive symptoms and regional cerebral blood flow (rCBF) in DAT. Methods: Technetium‐99m‐ethyl cysteinate dimer (^99mTc‐ECD) single‐photon emission computed tomography (SPECT) and Japanese version of the Neuropsychiatric Inventory (NPI) were carried out in 35 patients diagnosed as having mild–moderate DAT according to DSM‐IV. These patients were divided into the depressive group (D group: n = 17) and non‐depressive group (ND group: n = 18) using the NPI depression items. All data from SPECT images were analyzed using 3DSRT software. On 3DSRT the perfusion ratios (rCBF of bilateral callosomarginal, precentral, central, parietal, angular, temporal, posterior cerebral, pericallosal, lenticular nucleus, thalamus and hippocampus/cerebellar hemisphere) of each segment were compared between the D group and the ND group. Results: The perfusion ratios of the left callosomarginal segment for the D group were significantly lower (P < 0.05) than those of the ND group. Conclusions: Hypoperfusion in the left frontal cortex contributes to the expression of depressive symptoms in patients with DAT.     

Altered cerebral blood flow patterns associated with pathologic worry in the elderly

Background: Generalized anxiety disorder (GAD) is the most prevalent anxiety disorder among the elderly and has high functional and cognitive morbidity. However, late‐life GAD is relatively understudied and its functional neuroanatomy is uncharted. Several imaging studies have suggested abnormalities in the cognitive control systems of emotion regulation in anxiety disorders in young adults. The aim of this study was to examine the neural correlates of emotion regulation in late‐life GAD. Method: We compared 7 elderly GAD subjects and 10 elderly nonanxious comparison subjects using functional MRI. Regional cerebral blood flow (rCBF) was measured using pulsed arterial spin labeling perfusion MRI at rest and during an emotion regulation paradigm. Results: Relative to the rest condition, elderly nonanxious comparison subjects had increased rCBF during worry induction (WI) in the right insula, bilateral amygdala, and associative temporooccipital areas. Elderly GAD subjects had increased rCBF during WI in the associative temporooccipital areas, but not in the insula or the amygdala. During worry suppression (WS), elderly nonanxious comparison subjects had increased rCBF in the prefrontal cortex (PFC) and dorsal ACC. Elderly GAD subjects had no changes in rCBF during WS in the PFC. Conclusions: When attempting to regulate their emotional responses, elderly anxious subjects failed to activate prefrontal regions involved in the downregulation of negative emotions. These results, showing that elderly anxious subjects are not effectively engaging the PFC in suppressing worry, may be clinically relevant for developing personalized therapeutic strategies for the treatment of late‐life GAD. Depression and Anxiety 28:202–209, 2011. © 2011 Wiley‐Liss, Inc.     

Relationship between psychiatric symptoms and regional cerebral blood flow in patients with mild Alzheimer's disease

Background: Behavioral and psychological symptoms of dementia (BPSD) are frequently observed in patients with dementia and often cause serious problems. However, the cause of BPSD has not yet been elucidated. Moreover, the precise evaluation of BPSD in mild dementia has not been studied in any great detail. In the present study, we investigated the relationship between psychiatric symptoms and regional cerebral blood flow (rCBF) in patients with mild Alzheimer's disease (AD). Methods: The present study included 47 patients (20 men and 27 women) who were diagnosed with mild AD. Mean patient age was 72.8 ± 8.2 years. Single photon emission computed tomography (SPECT) with ^99mTc‐ethyl cysteinate dimer (^99mTc‐ECD) was performed in all patients. The SPECT data were analyzed using a three‐dimensional stereotactic region of interest template, which evaluated CBF in 24 segments. Psychiatric symptoms were evaluated in patients using the Brief Psychiatric Rating Scale. Each psychiatric symptom was designated as ‘symptom present’ in cases in which the BPRS item score was more than 3. We compared 10 segments of rCBF in symptom‐present patients with those in symptom‐absent patients. Results: Motor retardation was the most common psychiatric symptom (36.2%), followed by depression (19.1%), anxiety (17.0%), emotional withdrawal (17.0%), and somatic concern (14.9%). Alzheimer's disease patients with motor retardation exhibited a tendency towards lower rCBF in seven segments (left callosomarginal, bilateral parietal, bilateral angular, and bilateral temporal). However, no specific tendency was observed in depression, anxiety, and somatic concern. Conclusions: In the present study, we observed a tendency for decreased brain perfusion in patients with motor retardation. Further studies are necessary to confirm that this trend contributes to the appearance of psychiatric symptoms in patients with mild AD.     

Changes in regional cerebral blood flow in the right cortex homologous to left language areas are directly affected by left hemispheric damage in aphasic stroke patients: evaluation by Tc‐ECD SPECT and novel analytic software

Background: The objective of this study was to clarify the influence of regional cerebral blood flow (rCBF) changes in language‐relevant areas of the dominant hemisphere on rCBF in each region in the non‐dominant hemisphere in post‐stroke aphasic patients. Methods: The study subjects were 27 aphasic patients who suffered their first symptomatic stroke in the left hemisphere. In each subject, we measured rCBF by means of 99mTc‐ethylcysteinate dimmer single photon emission computed tomography (SPECT). The SPECT images were analyzed by the statistical imaging analysis programs easy Z‐score Imaging System (eZIS) and voxel‐based stereotactic extraction estimation (vbSEE). Segmented into Brodmann Area (BA) levels, Regions of Interest (ROIs) were set in language‐relevant areas bilaterally, and changes in the relative rCBF as average negative and positive Z‐values were computed fully automatically. To assess the relationship between rCBF changes of each ROIs in the left and right hemispheres, the Spearman ranked correlation analysis and stepwise multiple regression analysis were applied. Results: Globally, a negative and asymmetric influence of rCBF changes in the language‐relevant areas of the dominant hemisphere on the right hemisphere was found. The rCBF decrease in left BA22 significantly influenced the rCBF increase in right BA39, BA40, BA44 and BA45. Conclusions: The results suggested that the chronic increase in rCBF in the right language‐relevant areas is due at least in part to reduction in the trancallosal inhibitory activity of the language‐dominant left hemisphere caused by the stroke lesion itself and that these relationships are not always symmetric.     

A case of delusional disorder,somatic type with remarkable improvement of clinical symptoms and single photon emission computed tomograpy findings following modified electroconvulsive therapy

A 72-year-old male with delusional disorder, somatic type (DDST), was treated by modified electroconvulsive therapy (mECT). His somatic delusions were completely resolved by mECT. In parallel with the improvement of his clinical symptoms, we observed an improvement of regional cerebral blood flow (rCBF) in the left temporal and parietal lobes shown by the single photon emission computed tomograpy (SPECT). This study appears to support the utility of mECT for somatic delusions in elderly patients and suggests possible association of the dysfunction in the left temporal and parietal lobes with manifestation of the somatic delusion of the patient.     

Brain perfusion asymmetry in patients with oral somatic delusions

Oral cenesthopathy is a somatic delusion or hallucination involving the oral area and is categorized as a delusional disorder, somatic type. The pathophysiology of this intractable condition remains obscure. In this study, we clarified the pathophysiology of oral cenesthopathy by evaluating regional brain perfusion. We performed single photon emission computed tomography (SPECT) using ^99mTc-ethylcysteinate dimer in 16 subjects (cenesthopathy:control = 8:8). The SPECT images were visually assessed qualitatively, and quantitative analyses were also performed using a three-dimensional stereotactic region-of-interest template. The visual assessment revealed a right > left perfusion asymmetry in broad areas of the brain among the patients. The quantitative analysis confirmed that the regional cerebral blood flow values on the right side were significantly larger than those on the left side for most areas of the brain in the patients. A comparison of the R/(R + L) ratios in both groups confirmed the significant brain perfusion asymmetry between the two sides in the callosomarginal, precentral, and temporal regions in the patients. Qualitative evaluation of the SPECT images revealed right > left brain perfusion asymmetry in broad regions of the brain. Moreover, the quantitative analyses confirmed the perfusion asymmetry between the two sides in the frontal and temporal areas. Those may provide the key for elucidation of the pathophysiology of oral cenesthopathy.     

Brain SPECT imaging in children and adolescents with obsessive-compulsive disorder

Summary. Objective: To evaluate the patterns of regional cerebral blood flow (rCBF) in cortical and subcortical regions by Brain SPECT imaging, in children and adolescents with obsessive-compulsive disorder (OCD) before and after treatment.Method: Fourteen OCD patients (6 to 17 years old) underwent brain SPECT; ten of those subjects were reexamined after successful treatment. rCBF ratios were correlated with clinical parameters on the 14 patients in symptomatic state, and we compared rCBF ratios of the ten patients before and after treatment.Results: There was no statistically significant difference in average ratios of rCBF before and after treatment. There were significant clinical correlations between current age and age of onset of OCD and rCBF in the bilateral superior frontal, and bilateral parietal cortical regions.Conclusions: Further investigations on abnormal neurodevelopment of cortical-subcortical circuits possibly involved in symptomatology of paediatric OCD are warranted.     

Perfusion MRI detects rCBF abnormalities in early stages of HIV-cognitive motor complex

OBJECTIVE: To evaluate patients with early HIV-cognitive motor complex (HIV-CMC) for possible regional cerebral blood flow (rCBF) abnormalities on perfusion MRI (pMRI). BACKGROUND: Nuclear medicine techniques have demonstrated global and focal cerebral perfusion abnormalities in patients with HIV dementia. Ultrafast pMRI enables the measurement of rCBF throughout the brain without the need to apply radioactive tracers or ionizing radiation. METHODS: pMRI was used to measure the rCBF in 19 patients with early stages of HIV-CMC and 15 healthy seronegative control subjects. The rCBF maps were registered to high-resolution anatomic MRI scans and transformed into Talairach space. Statistical analysis of the rCBF maps was performed with SPM96. RESULTS: Compared with the control subjects, the patients with HIV had statistically significantly decreased rCBF bilaterally in the inferior lateral frontal cortices (right: -15%, p < 0.002; left: -12%, p < 0.005) and in the inferior medial parietal brain region (-15%, p < 0.0009). In contrast, rCBF was increased bilaterally in the posterior inferior parietal white matter (right: +19%, p < 0.0001; left: + 17%, p < 0.001). Furthermore, rCBF abnormalities correlated significantly with clinical disease severity as measured by CD4 count, plasma viral load, Karnofsky score, and HIV dementia scale. DISCUSSION: Our results are consistent with previous findings from PET and SPECT studies. Furthermore, pMRI can detect rCBF abnormalities that correlate with disease severity in HIV-CMC. Because pMRI is more cost-effective, faster, and safer than nuclear medicine techniques for monitoring rCBF changes, pMRI may be more feasible for monitoring the effects of therapy for HIV-CMC.     

A single photon emission computerized tomography (SPECT) study of regional cerebral blood flow in bipolar disorder

Data on functional imaging of bipolar disorder (BD) utilizing single photon emission computerized tomography (SPECT) is limited. This study assessed regional cerebral blood flow (rCBF), using ^99mTc-ECD SPECT, among patients with BD, with mania (N=10) or depression (N=10), compared with 10 patients with unipolar depression and 10 normal controls. Regions of interest were analysed using a semi-automatic brain quantification programme. Compared to controls, patients with mania had significantly reduced perfusion mainly in the left frontal area, also in the left anterior cingulate and parietal cortices; those with bipolar depression had significantly lowered rCBF principally in the anterior temporal regions bilaterally, as well as the left parietal area. Patients with unipolar depression had significantly lowered perfusion than controls in most of the regions examined, chiefly in the anterior temporal and frontal cortices bilaterally; they also had lowered perfusion in the right anterior temporal and frontal areas, as well as the right middle temporal area and the right thalamus, compared to patients with mania. Increased severity of psychotic symptoms was associated with reduced rCBF in patients. These results indicate that altered blood flow in the frontal-subcortical systems characterises patients with BD, as well as those with unipolar depression.     

Tc-99 HMPAO SPECT study of regional cerebral blood flow in olanzapine-treated schizophrenic patients

Dopamine D₂ blocking typical antipsychotic drugs are known to change the cerebral perfusion patterns of schizophrenic patients, especially in the frontal cortex and basal ganglia. In recent years atypical antipsychotics such as olanzapine, which have high serotonin 5-HT_2A/dopamine D₂ occupation ratios, have been shown to be more effective in the treatment of schizophrenia symptoms. The aim of this study was to evaluate the regional cerebral blood flow (rCBF) of the schizophrenic patients treated with olanzapine in a within-subject design. Twenty-four patients with schizophrenia participated as subjects in the study. Each subject was scanned in a medication-free state and after 6 weeks of 10 mg/day fixed dose olanzapine treatment. Despite the clinical improvement seen in the patients, repeated-measures analysis of variance showed that olanzapine produced no significant changes in cortical rCBF after the six-week treatment. This finding indicates that unlike typical antipsychotics olanzapine has no negative effect on cortical cerebral perfusion patterns of schizophrenic patients. Received: 12 December 2001 / Accepted: 5 December 2002 RID="*" ID="*"The preliminary report of this paper had been presented at 12^th European College of Neuropsychopharmacology Congress in London, 1999 and awarded by poster award. This work had been carried out at Erciyes University School of Medicine, departments of psychiatry and nuclear medicine. Correspondence to Ali Saffet Gonul, MD     

Changes in regional cerebral blood flow demonstrated by 99mTc-HMPAO SPECT in euthymic bipolar patients

Single photon emission computed tomography (SPECT) with ^99mTc-HMPAO was used to compare regional cerebral blood flow (rCBF) in patients with bipolar disorder and in healthy controls. The sample of this study consisted of 16 euthymic bipolar patients who met the DSM-IV criteria and 10 healthy control subjects. The mean regional cerebral blood flow values of the bipolar euthymic patients were significantly lower than those of the controls in the bilateral medial-basal temporal, occipital; medial frontal; parietal regions and in the cingulate gyrus; the hypoperfusion in the cingulate had the highest significant P value (.001, Bonferroni correction). No significant differences in rCBF emerged between right and left-brain regions. The most important findings of the current study are the presence of regional cerebral perfusion alterations, particularly in the cingulate gyrus in the euthymic bipolar patients. Our results imply that underlying brain dysfunction may be independent from manic or depressive episodes in bipolar disorder. Because of the small number of subjects, however, this finding should be viewed as preliminary. This study was presented as an oral presentation in the 7th International Congress of Nuclear Oncology and 18th National Congress of The Turkish Society of Nuclear Medicine 13–17 May 2006, Antalya, Turkey and in the International Conference on Mood Disorders 30 March–1 April 2006 Istanbul, Turkey.     

Cortical pattern of reduced perfusion in hearing loss revealed by ASL‐MRI

Age‐related hearing loss (HL) can be related to brain dysfunction or structural damage and may result in cerebral metabolic/perfusion abnormalities. Arterial spin labeling (ASL) magnetic resonance imaging (MRI) allows investigating noninvasively brain perfusion changes. Pseudocontinuous ASL and T1‐weighted MRI (at 3 T) and neuropsychological testing (Montreal Cognitive Assessment) were performed in 31 HL (age range = 47–77 years, mean age ± SD = 63.4 ± 8.4 years, pure‐tone average [PTA] HL > 50 dB) and 28 normal hearing (NH; age range = 48–78 years, mean age ± SD = 59.7 ± 7.4 years) subjects. Cerebral blood flow (CBF) and gray matter volume (GMV) were analyzed in the cortical volume to assess perfusion and structural group differences. Two HL subjects showing cognitive impairment were excluded from group comparisons. No significant differences in either global or local atrophy were detected between groups but the HL group exhibited significant regional effects of reduced perfusion within the bilateral primary auditory cortex, with maximal CBF difference (?17.2%) in the right lateral Heschl's gyrus. For the whole sample of HL and NH subjects (n = 59 = 31 HL + 28 NH), the regional CBF was correlated positively to the regional GMV (p = 0.020). In HL subjects (n = 31), the regional CBF was correlated negatively to the audiogram steepness (frequency range: 2–4 kHz, right ear: p = 0.022, left ear: p = 0.015). The observed cortical pattern of perfusion reduction suggests that neuronal metabolism can be related to HL before the recognition of brain structural damage. This also illustrates the potential of ASL‐MRI to contribute early functional markers of reduced central processing associated with HL.     

Muscarinic acetylcholine receptor status in Alzheimer’s disease assessed using (R,R) <Superscript>123</Superscript>I-QNB SPECT

Abstract Background One of the most characteristic changes in Alzheimer's disease (AD) is a deficit in cortical cholinergic neurotransmission and associated receptor changes. Objective To investigate differences in the distribution of M1/M4 receptors using (R, R) ¹²³I-iodo-quinuclidinyl-benzilate (QNB) and single photon emission computed tomography (SPECT) in patients with mild/moderate AD and agematched controls. Also, to compare ¹²³I-QNB uptake to the corresponding changes in regional cerebral blood flow (rCBF) in the same subjects. Methods Forty two subjects (18 AD and 24 healthy elderly controls) underwent ¹²³IQNB and perfusion ^99mTc-exametazime SPECT scanning. Image analysis was performed using statistical parametric mapping (SPM99) following intensity normalisation of each image to its corresponding mean whole brain uptake. Group differences and correlations were assessed using two sample t-tests and linear regression respectively. Results Significant reductions in ¹²³I-QNB uptake were observed in regions of the frontal rectal gyrus, right parahippocampal gyrus, left hippocampus and areas of the left temporal lobe in AD compared to controls (height threshold of p ≤ 0.001 uncorrected). Such regions were also associated with marked deficits in rCBF. No significant correlations were identified between imaging data and clinical variables. Conclusion Functional impairment as measured by rCBF is more widespread than changes in M1/M4 receptor density in mild/moderate AD, where there was little or no selective loss of M1/M4 receptors in these patients that was greater than the general functional deficits shown on rCBF scans.     

In child and adult migraineurs the somatosensory cortex stands out … again: An arterial spin labeling investigation

Over the past decade, human brain imaging investigations have reported altered regional cerebral blood flow (rCBF) in the interictal phase of migraine. However, there have been conflicting findings across different investigations, making the use of perfusion imaging in migraine pathophysiology more difficult to define. These inconsistencies may reflect technical constraints with traditional perfusion imaging methods such as single‐photon emission computed tomography and positron emission tomography. Comparatively, pseudocontinuous arterial spin labeling (pCASL) is a recently developed magnetic resonance imaging technique that is noninvasive and offers superior spatial resolution and increased sensitivity. Using pCASL, we have previously shown increased rCBF within the primary somatosensory cortex (S1) in adult migraineurs, where blood flow was positively associated with migraine frequency. Whether these observations are present in pediatric and young adult populations remains unknown. This is an important question given the age‐related variants of migraine prevalence, symptomology, and treatments. In this investigation, we used pCASL to quantitatively compare and contrast blood flow within S1 in pediatric and young adult migraineurs as compared with healthy controls. In migraine patients, we found significant resting rCBF increases within bilateral S1 as compared with healthy controls. Furthermore, within the right S1, we report a positive correlation between blood flow value with migraine attack frequency and cutaneous allodynia symptom profile. Our results reveal that pediatric and young adult migraineurs exhibit analogous rCBF changes with adult migraineurs, further supporting the possibility that these alterations within S1 are a consequence of repeated migraine attacks. Hum Brain Mapp 38:4078–4087, 2017. © 2017 Wiley Periodicals, Inc.     

Changes of regional cerebral blood flow in stroke patients assessed by SPECT]

The aim of our work was to evaluate changes in regional cerebral blood flow (rCBF) in patients with TIA and/or completed stroke and localisation of fotopenic foci in basal conditions and, in some cases, after stimulation pharmacological trial with acetazolamide. One hundred and fifty three patients participated in the study--105 with completed stroke and 48 with TIA. Regional CBF (rCBF) was evaluated using a single-headed rotating gamma camera (Diacam, Siemens) with high resolution collimator, after injection of 740 MBq 99mTc-HMPAO (Ceretec, Amersham). Sixteen patients with TIA underwent SPECT at baseline and after injection of acetazolamide (ACZ). Relative regional perfusion was expressed as the ratio of cerebral/cerebellar activity. In the completed stroke population, the perfusion ratios were significantly lower than those of controls and TIA at baseline (p < 0.001) and TIA after ACZ (p < 0.01). CONCLUSIONS: This study shows a significant difference in rCBF in patients with completed stroke and/or TIA and controls. In patients with TIA and rCBF similar to that observed in controls, perfusion deficits may be visible after ACZ injection.     

Interictal cerebral blood flow abnormality in cryptogenic West syndrome

Purpose: To elucidate the abnormality of interictal regional cerebral blood flow (rCBF) of West syndrome at the onset . Methods: Quantitative measurement of rCBF with an autoradiography method using N‐isopropyl‐(¹²³I) p‐iodoamphetamine single photon emission computed tomography (SPECT) was performed on 14 infants with cryptogenic West syndrome. Regions of interest (ROIs) for rCBF were placed automatically using an automated ROI analysis software (three‐dimensional stereotactic ROI template), and were grouped into 12 segments: callosomarginal, precentral, central, parietal, angular, temporal, posterior cerebral, pericallosal, lenticular nucleus, thalamus, hippocampus, and cerebellum. We compared rCBF between the patients and seven age‐matched infants with cryptogenic focal epilepsy as a control group. The patients were divided into two groups according to the duration from onset to SPECT, to compare rCBF. Results: Quantitative analysis revealed cerebral hypoperfusion in cryptogenic West syndrome with normal SPECT images under visual inspection. In bilateral central, posterior cerebral, pericallosal, lenticular nucleus, and hippocampus, and in the left parietal, temporal, and cerebellum, and in the right angular and thalamus segments there were statistical differences (p < 0.05). Compared with the duration from onset to SPECT, there were no significant differences of rCBF in all segments. Discussion: Broad cerebral hypoperfusion with posterior predominance involving the hippocampus and lenticular nucleus implies that even cryptogenic West syndrome has a widespread cerebral dysfunction at least transiently, which would correspond to clinical manifestations of hypsarrhythmia and epileptic spasms. Hippocampal hypoperfusion suggests the dysfunction of hippocampal circuitry in the brain adrenal axis, and may contribute to subsequent cognitive impairment of cryptogenic West syndrome.     

The peak time difference of time–density curve in intravenous digital subtraction angiography correlates to an asymmetric cerebral blood flow as determined by positron emission tomography

A time–density curve study in contrast media transit is theoretically possible to evaluate an asymmetric cerebral perfusion. In this study, we confirmed the correlation between the peak time difference in a regional time–density curve and the asymmetry of cerebral blood flow using positron emission tomography (PET). Five patients with a unilateral occlusion of the carotid or middle cerebral artery underwent intravenous digital subtraction angiography and PET on two successive days. We placed four pairs of regions of interest as appropriate in each study, and obtained the peak time of a regional time–density curve, regional cerebral vascular blood flow (rCVBF) and regional cerebral blood flow (rCBF). We obtained a significant linear correlation between the right-to-left difference of peak time and the difference of 1/rCVBF (r = 0.85, p < 0.001). The peak time difference also showed good correlation to the absolute difference of rCBF (r = ?0.84, p < 0.001). A time–density curve study can detect the asymmetry of rCBF, and may be used to evaluate unilateral ischemic damages.     

Clinical symptoms and regional cerebral blood flow in schizophrenia

This study examined the relationship between clinical symptoms and regional cerebral blood flow (rCBF) in schizophrenic patients using single photon emission computed tomography (SPECT). The subjects were 26 medicated schizophrenic patients diagnosed according to DSM-III-R criteria. Clinical symptoms were assessed using the Scale for the Assessment of Negative Symptoms (SANS), selected items for the Positive and Negative Syndrome Scale (PANSS), and the scale for Schneider's first rank symptoms. Resting rCBF was measured using N-isopropyl-p-[I-123] iodoamphetamine (I-123 IMP) SPECT, and relative rCBF distribution was evaluated in nine regions of interest in each hemisphere. Factor analysis of symptom ratings indicated four separate syndromes: psychomotor poverty, alienation (hallucination and disturbance of the self), delusion, and disorganization. Stepwise multiple regression analysis showed the psychomotor poverty syndrome to be correlated with decreased rCBF in bilateral superior frontal areas and increased rCBF in the left thalamus and right basal ganglia. The disorganization syndrome was correlated with increases rCBF in bilateral anterior cingulates and decreased rCBF in bilateral midolle frontal areas. The alienation syndrome was shown related to increased rCBF in the right inferior frontal area and parietal area. Dysfunction in distinctive neural networks involving various prefrontal areas would thus appear to underlie these syndromes in schizophrenia.     

Variability of cerebral blood fow deficits in99mTc-HMPAO SPECT in patients with Alzheimer's disease

Summary The purpose of this study was to analyse the frequency of the different pathological perfusion patterns in SPECT in a clinical, unselected population of patients with Alzheimer's disease. In 91 patients and 16 control subjects regional cerebral blood flow (rCBF) was measured with Single Photon Emission Computed Tomography (SPECT) using^99mTc-hexa-methyl-propyleneamine oxime (HMPAO). 95% confidence intervals obtained from the perfusion values of the control subjects were used to define normal perfusion ranges.The frequency of perfusion deficits in the left frontal, temporal, parietal and occipital lobes were 62.2%, 60.4%, 70.3% and 23.1%, respectively. In the right hemisphere the corresponding values were 60.4%, 58.2%, 63.7% and 9.9%. With the exception of the occipital lobes these frequencies were not significantly different. The analysis of the perfusion pattern of each patient revealed 35 different combinations of lobes with perfusion deficits. The temporo-parietal perfusion deficits were not more frequent than the temporo-frontal perfusion deficits. These results suggest that in the clinical routine a high variety of heterogeneous rCBF patterns have to be expected.     

A SPECT study of apathy in Alzheimer's disease

BACKGROUND/AIMS: To assess the association between regional cerebral blood flow (rCBF) and apathy in Alzheimer's Disease (AD). METHODS: SPECT and MRI scans were obtained from 51 nondepressed outpatients meeting criteria for probable AD (age 77.6 +/- 6.6 years; MMSE 22.3 +/- 5.1; 23 apathetic, 28 nonapathetic) and 23 healthy elderly (75.6 +/- 3.8 years) controls. The following regions of interest (ROIs) were compared between apathetic and nonapathetic AD patients and then referenced against aged controls: anterior cingulate, orbitofrontal cortex, middle medial temporal cortex, hippocampus, medial superior temporal cortex, thalamus/hypothalamus and pons. RESULTS: Apathetic and nonapathetic patients had significant differences in rCBF. Relative to nonapathetic AD patients, apathetic AD patients had lower perfusion in 2 ROIs (right orbitofrontal cortex and left anterior cingulate) and higher perfusion in 5 ROIs (right and left hippocampi, left medial superior temporal gyrus, and right and left middle medial temporal cortex). Comparison of rCBF in these 7 ROIs to healthy elderly controls confirmed hypoperfusion in the left anterior cingulate and right orbitofrontal cortex and suggested a relative sparing of perfusion among apathetic AD patients in the remaining 5 ROIs. CONCLUSIONS: In this group of nondepressed patients with AD, apathetic subjects displayed significant perfusion differences compared to nonapathetic subjects.