Brain Single-photon Emission Tomography Research Articles

The Role of Ictal Brain Single Photon-Emission Tomography in Refractory Epilepsy Complementary to Magnetic Resonance Imaging and Electroencephalogram – Our Experience

Background: Correct identification of the epileptogenic zone (EZ) is essential for surgical success for focal epilepsy. There are multiple modalities which are available for detecting the anatomical and the functional abnormalities. The purpose of this study was to determine the complementary role of ictal brain single photon-emission tomography (SPECT) in delineating the EZ in addition to electroencephalogram (EEG) and magnetic resonance imaging (MRI). Methodology: Clinical and diagnostic data from patients with refractory epilepsy undergoing ictal brain SPECT (IEBS), EEG, MRI between 2014 and 2019 were analyzed retrospectively. Tc99m-ethyl cysteinate dimer was administered intravenously during or within 30 s of onset of seizure activity. Results: Eighty-nine patients aged: Four months-32 years (median age: Eight years) were studied. The concordance of IEBS with MRI and EEG were studied. Among them, EEG was normal in 22 and abnormal in 67 (multifocal: 40, unifocal: 8, generalized: 19). MRI was normal in 36, abnormal in 26, nonspecific in 24 and not done in three patients. Of the 80 patients showing tracer uptake in IEBS, 14-multifocal uptake and 66-unifocal uptake (EEG and MRI were not showing any abnormality in 15 and 27 patients, respectively). Unifocal uptake in IEBS was concordant with EEG in 11 (16.67%) and MRI in 15 (27.72%). The concordance and nonconcordance of the results among the two imaging modalities or EEG assuming surgical site as the gold standard was noted. Twenty-two had undergone surgical removal of the EZ, 15 was conformable with MRI or IEBS. Conclusion: In patients with noncontributory EEG and MRI, IEBS could detect the epileptogenic focus. Therefore, depending entirely on EEG and MRI may limit its diagnosis. IEBS, MRI and EEG are complementary to each other in the detecting the epileptogenic focus.

Effect of Low-Dose Statins in Addition to Standard Therapy on Brain Perfusion and Neurocognitive Performance in Patients with Major Depressive Disorder

Introduction: Major depressive disorder (MDD) is a prevalent condition which has a well-known association with ischemic cardiomyopathy, probably explained by an inflammatory mediator mechanism. Statins, besides reducing cholesterol production, have pleiotropic effects including anti-inflammatory activity. The goal was to evaluate the effect of statins as an addition to standard therapy on mood status, brain perfusion, and neurocognitive performance in MDD. Methods: We studied 20 MDD patients with brain single-photon emission tomography and Cambridge Neuropsychological Test Automated Battery (CANTAB), half randomized to 10 mg of Rosuvastatin or placebo, in addition to selective serotonin reuptake inhibitors (SSRIs) therapy and being reevaluated 3 months later. The images were compared using Statistical Parametric Mapping; clinical scores (Hamilton Depression Score with 17 items and Beck’s Depression Inventory) as well as neurocognitive parameters were applied as covariances (CoV) to estimate regional cerebral blood flow (rCBF) changes with both therapies. Results: Clinical scores decreased in both groups (p = 0.0001); Beck’s presented a larger decrease with statins. We observed significantly rCBF changes expressed as significant larger clusters of voxels (p < 0.05) in the pre/subgenual anterior cingulate plus orbitofrontal cortex and a small area in the posterior cingulate gyrus in the statins group, whereas it was not observed with placebo, when using clinical scores as CoV. A similar pattern of rCBF changes was present with emotions recognition, attentional, paired associates learning, spatial planning, and working memory tasks. Conclusion: Short-term use of low-dose statins in MDD patients under SSRIs results in important rCBF changes in key mood associated areas to improvement in neurocognitive performance. These findings, even though demonstrated in a small sample, could open a new therapeutic tool in the comprehensive management of this disorder.

Determinants of brain SPECT perfusion and connectivity in treatment-resistant depression

This study aims to characterize and compare functional brain single photon emission tomography (SPECT) perfusion and connectivity in treatment-resistant depression (TRD) according to distinct demographic or clinical profiles (male vs. female; old vs. young; unipolar vs. bipolar) and to study their relationship to the severity and the duration of episode/illness. We retrospectively included 127 consecutive patients who met DSM-IV criteria for a nonpsychotic major TRD episode. All patients were studied using 99mTc-ethyl cysteinate dimer SPECT. Whole-brain, voxel-based, between-groups analyses were performed according to demographic and clinical data and in comparison to 37 healthy subjects. Voxel-wise interregional correlation was also performed to compare functional SPECT connectivity. Finally, relationships were searched for regarding severity and duration of episode/illness. The whole group of patients exhibited significant hypoperfusion within bilateral fronto-temporal, insular, and anterior cingulate cortices, as well as within the left caudate. Functional connectivity between left frontal and left cerebellar regions was higher in patients than in healthy subjects. Gender, age, and type of mood disorder did not influence these SPECT patterns. A significant relationship was found between brain SPECT perfusion and either duration or global severity of illness in particular frontal areas. Our data support the hypothesis of a shared SPECT pattern, whatever the profile of TRD, involving fronto-temporal regions and the cerebellum.

Assessing response using 99mTc-MIBI early after interstitial chemotherapy with carmustine-loaded polymers in glioblastoma multiforme: preliminary results.

Introduction. Early signs of response after applying wafers of carmustine-loaded polymers (gliadel) are difficult to assess with imaging because of time-related imaging changes. 99mTc-sestamibi (MIBI) brain single-photon emission tomography (SPET) has reportedly been used to reveal areas of cellularity distinguishing recurrent neoplasm from radionecrosis. Our aim was to explore the role of MIBI SPET in assessing response soon after gliadel application in glioblastoma multiforme (GBM). Methods. We retrospectively reviewed the charts on 28 consecutive patients with a radiological diagnosis of GBM who underwent MIBI SPET/CT before surgery (with intracavitary gliadel placement in 17 patients), soon after surgery, and at 4 months. The area of uptake was selected using a volume of interest that was then mirrored contralaterally to obtain a semiquantitative ratio. Results. After adjusting for ratio at the baseline, the effect of treatment (gliadel versus non-gliadel) was not statistically significant. Soon after surgery, however, 100% of patients treated with gliadel had a decreased ratio, as opposed to 62.5% of patients in the non-gliadel group (P = 0.0316). The difference between ratios of patients with radical versus partial resection reached statistical significance by a small margin (P = 0.0528). Conclusions. These data seem to suggest that the MIBI ratio could be a valuable tool for monitoring the effect of gliadel early after surgery.

123I-ADAM SPET imaging of serotonin transporter in patients with epilepsy and comorbid depression

BackgroundPurpose of the study was to investigate alterations in midbrain serotonin transporter (SERT) binding in patients with epilepsy and symptoms of depression compared to patients with epilepsy with no symptoms of depression.MethodsWe studied 12 patients with epilepsy (7 patients had focal and 5 had generalized epilepsy syndromes). The presence of self-reported symptoms of depression was assessed using Beck Depression Inventory (BDI) and the Emotional State Questionnaire (EST-Q). The binding potential of the SERT was assessed by performing brain single photon emission tomography (SPET) using the SERT radioligand 2-((2-((dimethylamino)methyl)phenyl)thio)-5-(123)iodophenylamine (123I-ADAM).ResultsSeven patients had BDI and EST-Q subscale scores greater than 11 points, which was interpreted as the presence of symptoms of depression. We found that 123I-ADAM binding was not significantly different between patients with epilepsy with and without symptoms of depression. In addition, 123I-ADAM binding did not show a significant correlation to either BDI or EST-Q depression subscale scores and did not differ between patients with focal vs. generalized epilepsy.ConclusionThe results of our study failed to demonstrate alterations of SERT binding properties in patients with epilepsy with or without symptoms of depression.

Reverse Fox test for detecting visuospatial dysfunction corresponding to parietal hypoperfusion in mild Alzheimer's disease.

We developed a novel visuospatial clinical task to detect parietal dysfunction in mild Alzheimer's disease (AD). A total of 65 outpatients, including 47 with mild AD and 18 cognitively and neuroradiologically normal individuals with subjective memory impairment (NL), performed the "Reverse Fox" test and underwent brain single photon emission tomography. Patients with AD were divided into subgroups according to the results of the Reverse Fox test (successful vs unsuccessful). Success in the Reverse Fox test was achieved by 31.9% of patients with AD and 94.4% of NL. The unsuccessful AD subgroup had reduced perfusion of the medial parietal and bilateral temporoparietal regions compared with the successful AD subgroup. Failure in the Reverse Fox test was related to parietal hypoperfusion in patients with mild AD. Our findings suggest that the Reverse Fox test may be one of the useful supporting tools for detecting mild AD at outpatient clinic.

Combined Treatment of Methylprednisolone Pulse and Memantine Hydrochloride Prompts Recovery from Neurological Dysfunction and Cerebral Hypoperfusion in Carbon Monoxide Poisoning: A Case Report

A 49-year-old healthy man developed sudden unconsciousness under inadequate ventilation. Blood gas analysis showed carboxyhemoglobin of 7.3%. After normobaric oxygen therapy, he recovered completely 7 days later. At 3 weeks after carbon monoxide (CO) exposures, memory and gait disturbances appeared. Neurological examination revealed Mini-Mental State Examination (MMSE) score of 5 of 30 points, leg hyper-reflexia with Babinski signs, and Parkinsonism. Brain fluid-attenuated inversion recovery imaging disclosed symmetric hypointense lesions in the thalamus and the globus pallidus, and hyperintense lesions in the cerebral white matter. Brain single-photon emission tomography (SPECT) scanning with (99m)Technesium-ethyl cysteinate dimer displayed marked hypoperfusion in the cerebellum, the thalamus, the basal ganglia, and the entire cerebral cortex. He was diagnosed as CO poisoning and treated with hyperbaric oxygen therapy. The neurological deficits were not ameliorated. At 9 weeks after neurological onset, methylprednisolone (1000 mg/day, intravenous, 3 days) and memantine hydrochloride (20 mg/day, per os) were administered. Three days later, MMSE score was increased from 3 to 20 points. Neurological examination was normal 3 weeks later. Brain SPECT exhibited 20% increase of regional cerebral blood flows in the cerebellum, the thalamus, the basal ganglia, and the entire cerebral cortex. These clinicoradiological changes supported that the treatment with steroid pulse and memantine hydrochloride could prompt recovery from neurological dysfunction and cerebral hypoperfusion. Further clinical trials are warranted whether such combined therapy can attenuate neurological deficits and cerebral hypoperfusion in patients with CO poisoning.

The comparison of pre- and post-treatment 99mTc HMPAO brain SPECT images in patients with obsessive-compulsive disorder

The objective of the present study was to compare brain activation in patients with obsessive-compulsive disorder (OCD) who received pharmacotherapy (selective serotonin reuptake inhibitor (SSRI) or a SSRI–risperidone combination) with that in healthy controls using 99mTc-hexamethyl propyleneamine oxime (HMPAO) brain single photon emission tomography (SPECT). Twelve OCD patients achieving clinical response (seven SSRI responders, five patients responded to SSRI plus risperidone) underwent post-treatment SPECT scan. The baseline regional cerebral blood flow (rCBF) was significantly reduced in a large part of the cerebral cortex and the left cingulate gyrus in OCD patients compared with controls. After a 50% reduction of the OCD symptoms, bilaterally increased rCBF in the thalamus showed a significant effect of time in both of the patient groups. In the remitted state, although rCBF in the cingulate gyrus did not differ in SSRI responders compared with controls, patients who responded to the combination of SSRI+ risperidone showed significant hypoperfusion in the left anterior cingulate gyrus. SSRI responders had normalized rCBF in the frontal region relative to the control group. Consequently, based on our results, we attribute the observed thalamic rCBF alteration to SSRI treatment. Our results also suggested that brain perfusion changes associated with clinical remission may differ across patient subgroups.

The influence of resolution recovery by using collimator detector response during 3D OSEM image reconstruction on (99m)Tc-ECD brain SPET images.

Partial volume effect, due to the poor spatial resolution of single photon emission tomography (SPET), significantly restricts the absolute quantification of the regional brain uptake and limits the accuracy of the absolute measurement of blood flow. In this study the importance of compensation for the collimator-detector response (CDR) in the technetium-99m ethyl cysteinate dimer ((99m)Tc-ECD) brain SPET was assessed, by incorporating system response in the ordered-subsets expectation maximization (OSEM) reconstruction algorithm. By placing a point source of (99m)Tc at different distances from the face of the collimator, CDR were found and modeled using Gaussian functions. A fillable slice of the brain phantom was designed and filled by (99m)Tc. Projections acquired from the phantom and also 4 patients who underwent the (99m)Tc-ECD brain SPET were used in this study. To reconstruct the images, 3D OSEM algorithm was used. System blurring functions were modeled, during the reconstruction in both projection and backprojection steps. Our results were compared with the conventional resolution recovery using Metz filter in filtered backprojection (FBP). Visual inspection of the images was performed by six nuclear medicine specialists. Quantitative analysis was also studied by calculating the contrast and the count density of the reconstructed images. For the phantom images, background counts and noise were decreased by 3D OSEM compared to the FBP-Metz method. Quantitatively, the ratio of the counts of the occupied hot region to that of the cold region of the reconstructed by FBP-Metz images was 1.14. This value was decreased from 1.12 to 0.86 for 3D OSEM of 2 and 30 iterations respectively. The reference value was 0.85 for the planar image. For clinical images, hot to cold regions (grey to white matter), the count ratio was increased from 1.44 in FBP-Metz to 3.2 and 4 in 3D OSEM with 10 and 20 iterations respectively. Based on the interpretability of images, the best scores (3.79±0.51) by the physicians were given to the images reconstructed by 3D OSEM and 10 iterations. This value was 0.63±0.77 for FBP-Metz images. In conclusion, by incorporating the distance dependent CDR during 3D OSEM, it was possible to reconstruct the brain images with much higher resolution and contrast as compared to the conventional resolution recovery method, which used FBP-Metz. It was however important to make a trade-off between noise and resolution by determining an optimum iterations number.

Is there still a place for SPET in the era of PET brain imaging?

Although positron emission tomography (PET) may be credited with providing the impetus for the new clinical interest in functional neuroimaging and currently is an increasingly important imaging tool for noninvasive assessment of brain tumors, single-photon emission tomography (SPET) has offered an alternative technique with the relative advantages of lower price and wide availability. Brain SPET has been proven useful in the differentiation of tumor recurrence from radiation necrosis, in the non-invasive assessment of gliomas and meningiomas aggressiveness, in differentiating neoplastic from non neoplastic intracerebral haemorrhage, in monitoring treatment response and estimating patients' prognosis. Thus, SPET may still have a role in the diagnosis and characterization of brain tumors. Future comparative studies between SPET and PET or latest magnetic resonance based neuroimaging techniques are warranted.

Alleviation of Brain Hypoperfusion after Preventative Treatment with Lomerizine in an Elderly Migraineur with Aura

Previous studies of brain single-photon emission tomography (SPECT) showed changes of regional cerebral blood flow (rCBF) in migraineurs during prodromes or headache attacks. Little is known about how successful medication of migraine prevention can reflect rCBF in migraineurs. We highlighted alternation of brain SPECT findings in a migraineur with aura before and after prophylactic treatment with lomerizine, a calcium channel blocker. A 70-year-old man with migraine developed visual disturbance frequently at walking exercise for the recent 3 months. After this visual attack, a mild-degree of throbbing headache occured occasionally. Brain SPECT using 99mTc-ethyl cysteinate dimer was performed at interictal time of migraine. Brain SPECT before lomerizine treatment revealed hypoperfusion in the frontal, parietal, and occipital regions. He was diagnosed with recurrence of migraine with aura (MA). Lomerizine (10 mg/day, po) was administered for 3 months. MA and visual aura without headache were dramatically improved. Migraine attacks and visual disturbance were not induced at exercise. At 3 months after lomerizine medication, brain SPECT showed remarkable increase of rCBF. These SPECT changes of our patient indicated that antimigraine mechanism of lomerizine could contribute to restoration of cerebral hypoperfusion.

Squalor Syndrome After Focal Orbitofrontal Damage

To investigate a responsible lesion for squalor syndrome. Squalor syndrome is a behavioral disorder characterized by extreme self-neglect and domestic squalor. Although frontal lobe dysfunction has been postulated to account for squalor syndrome, the relevant part of the frontal lobe has not been elucidated. A 49-year-old housewife who suffered rupture of an anterior communicating artery aneurysm at the age of 40 years was examined using a wide range of neuropsychologic tasks. Computed tomography of the head and brain single photon emission tomography with IMP was also carried out. Her performance on neuropsychologic testing was within the normal range, except for the gambling task. Computed tomography of the head showed low-density areas in the bilateral orbitofrontal cortices, basal forebrain, and right ventromedial caudate. Brain single photon emission tomography with IMP showed decreased regional cerebral blood flow in the bilateral orbitofrontal cortices and the basal forebrain. Our findings suggest that an orbitofrontal lesion may be responsible for squalor syndrome by leading to inappropriate decision-making and abnormal impulsivity.

Olmesartan, an Angiotensin II Receptor Blocker, Restores Cerebral Hypoperfusion in Elderly Patients With Hypertension

We evaluated the effects of olmesartan, an angiotensin II receptor blocker (ARB), on cerebral blood flow (CBF) in elderly and hypertensive subjects. Ten subjects with first- or second-degree essential hypertension (mean age, 70.5 years) underwent brain single-photon emission tomography (SPECT) scanning with (99m)Tc-ethyl cysteinate dimer before and after a 24-week course of olmesartan. Mean systolic blood pressure (SBP) was 156.2+/-9.9 mm Hg, and mean diastolic blood pressure (DBP) was 89.1+/-5.5mm Hg. No subject had any abnormalities on neurologic examination or previous history of stroke or cardiovascular disease. Before olmesartan administration, the hypertensive subjects had approximately 15% less whole brain CBF compared with age-matched normotensive controls. Regional CBF was decreased by 11%-20% in the frontal, parietal, temporal, and posterior lobes. Olmesartan treatment significantly decreased SBP to 130.4+/-4.2mm Hg (P < .001) and DBP to 78.2+/-7.0mm Hg (P < .001). After 24 weeks of olmesartan treatment, CBF of whole brain and regional CBF of the frontal, parietal, and temporal lobe were similar to those of control subjects. Our brain SPECT data indicate that olmesartan restores brain hypoperfusion in elderly and hypertensive patients without organic damage. This ARB may have a favorable potential for cerebrovascular circulation, in addition to a blood pressure-lowering effect.

Peduncular hallucinosis: A polysomnographic and spect study of a patient and efficacy of serotonergic therapy

Peduncular hallucinosis (PH) consists of formed and coloured visual images, which the patient knows are unreal; it is often associated with lesions of the pons, midbrain and diencephalon. A 72-year-old man had noted the sudden onset of visual hallucinations one year before, specifying the time and body position in a 4-week, 24-h diary. Thereafter, he underwent video-polysomnography (VPSG), brain magnetic resonance imaging (MRI), angiography (MRA), proton spectroscopy ( 1H MRS), and single photon emission tomography (SPECT). Patient’s diaries and VPSG showed a strong clustering of hallucinatory experiences during the evening/night time while lying in supine position, similar to hypnagogic hallucination and sleep paralysis in supine position. Repeated episodes of REM sleep behaviour disorder (RBD) occurred during the night. MRI and MRA showed an elongated and dilated left internal carotid artery displacing the left subthalamus upwards, and 1H MRS relatively decreased N-acetyl-aspartate in the left subthalamus. Brain SPECT during PH revealed hypoperfusion in the right temporal region and hyperperfusion in the left occipital and right opercular regions (the latter possibly related to the patient’s awareness of unreality). PH resolved with serotonergic (citalopram) therapy.

Dopamine Transporter SPECT/CT and Perfusion Brain SPECT Imaging in Idiopathic Basal Ganglia Calcinosis

A case of idiopathic basal ganglia calcification in a 56-year-old woman with parkinsonism and cognitive impairment is described. The nigrostriatal dopaminergic pathway and regional cerebral blood flow were evaluated using dopamine transporter (DAT) brain single photon emission tomography combined with a low-dose x-ray computerized tomography transmission (hybrid SPECT/CT) and Tc-99m HMPAO brain perfusion SPECT study, respectively. DAT SPECT/CT imaging revealed a reduction in DAT binding in both striatum regions coinciding with bilateral calcifications in the basal ganglia. Brain perfusion scan showed hypoperfusion in basal ganglia regions, posterior parietal cortex bilaterally, left frontopolar and dorsolateral prefrontal cortex, and left temporal lobe. These findings correlated well with the clinical condition of the patient. Mineralization may play a critical role in the pathogenesis of neuronal degeneration. Cortical perfusion changes in patients may better explain the patient's altered cognitive and motor functions.

Tau haplotype influences cerebral perfusion pattern in frontotemporal lobar degeneration and related disorders

The modulating factors on phenotypic expression of frontotemporal lobar degeneration (FTLD) remain still unknown. The aim of this study was to determine whether tau genetic variability modulates the brain functional and the clinical phenotypic expression of FTLD. Clinical and neurological evaluations, a standardized neuropsychological assessments as well as a brain single photon emission tomography perfusion imaging studies were performed in 48 FTLD patients. Cerebral perfusion patterns were analysed according to H1 or H2 tau haplotypes by statistical parametric mapping and principal component analysis. Two different patterns of cerebral dysfunction characterized the haplotypes, as hypoperfusion of frontal medial and cingulated cortex in H2-carriers and a prevalent involvement of posterior parietal regions in H1-carriers. Further, a significant increase of cerebrospinal fluid total tau and phospho tau levels was found in H2-carriers. These findings support a role of tau haplotype in modulating disease phenotype by influencing the hypoperfusion pattern and cerebrospinal fluid tau levels in FTLD.

もやもや病の統計学的脳血流ＳＰＥＣＴ画像解析

To investigate pathophysiology of moyamoya disease, we analyzed brain single photon emission tomography (SPECT) images of patients with this disease by using interface software for a 3-dimensional (3D) data extraction format. Presenting symptoms were TIA in 21 patients and hemorrhage in 6 patients. All the patients underwent brain SPECT scan of 123I-IMP at rest and after acetazolamide challenge (17 mg/kg iv, 2-day method). Cerebral blood flow (CBF) was quantitatively measured using arterial blood sampling and an autoradiography model. The group of the patients who presented with TIAs showed decreased CBF in the frontal lobe at rest compared to that of patients with hemorrhage, but Z-score ((mean—patient data)/SD) did not reach statistical significance. Significant CBF decrease after acetazolamide challenge was observed in a wider cerebral cortical area in the TIA group than in the hemorrhagic group. The brain region of hemodynamic ischemia (stage II) correlated well with the responsible cortical area for clinical symptoms of TIA. A hemodynamic ischemia stage image clearly represented recovery of reserve capacity after bypass surgery. Statistical evaluation of SPECT may be useful to understand and clarify the pathophysiology of this disease.

Is it possible to predict the long-term response to venlafaxine with the use of biological markers and psychophysiological methods?

Introduction The present study investigated whether it is possible to predict the medium term response to venlafaxine using biological markers and psychophysiological methods. Material Fourteen (14) patients aged 21–60 years suffering from Major Depression according to DSM-IV were included in the study. Methods The SCAN v 2.0 and the IPDE were used to assist clinical diagnosis. Patients were investigated with electrooculogram (EOG), Pattern-Reversal Visual Evoked Potentials (PR-VEPs), Dexamethasone Suppression Test (DST), d-fenfluramine Challenge Test, and brain Single Photon Emission Tomography (SPECT). Venlafaxine 150–225 mg per os daily was administered. The follow-up period was 2 years. Statistical analysis Chi-square test and ANOVA were used for the analysis of data. Results There was a lower left globus pallidus regional cerebral blood flow in patients with better response. On the contrary, chronic patients were closer to normality. Discussion The results of the current study provide preliminary evidence concerning our ability to predict response to venlafaxine and to understand its way of action.

The role of Tc-99m-HMPAO SPET perfusion neuroimaging and cerebrovascular reactivity to acetazolamide in patients with mild cognitive impairment

Background In contrast to the physiological age related decline of cognitive functions, mild cognitive impairment (MCI) is considered an early stage of dementia. In the presence of vascular risk factors, it is difficult to differentiate early stages of Alzheimer's disease (AD) from those of vascular dementia (VD), solely on the basis of clinical and neuroimaging (CT, MRI) findings. Single photon emission tomography (SPET) is a technique to obtain functional tomographic images of the 3-dimensional distribution of a radiopharmaceutical. One of the most widely used radiopharmaceutical for regional Cerebral Blood Flow (CBF) SPET is Technetium-99m (Tc-99m) labelled compound with HMPAO (Ceretec; Nycomed Amersham). After intravenous injection the Tc-99m-HMPAO lipophilic compound cross the intact blood brain barrier, distribute in the brain proportional to local blood flow and is retained in the brain with a fixed regional distribution for a sufficient time period to permit image acquisition. The peak brain activity is reached within 2 min post-injection. Since there is no redistribution, the initial tracer uptake and distribution remains almost unchanged for several hours and are independent of rCBF variations occurring after the fixation time (frozen images, which represent the rCBF at the time of injection). Acetazolamide (Diamox) is known to increase Cerebral Blood Flow (CBF) without changing the cerebral metabolic rate of oxygen. Patients with compromised circulation and resultant reduced CBF due to reduced perfusion pressure does not respond to acetazolamide. However, little is known about the cerebrovascular reactivity (CVR) in patients with MCI due to degenerative or perfusion related memory disturbances. Materials and methods This study included 18 patients with demonstrated (clinic and neuropsychologic findings) MCI. There were ten men and eight women (age range 52–82 years, mean 69 years) with neurological clinical examination including Hachinski scale score. Computerized tomography (CT) scanning and Magnetic resonance (MR) imaging was performed in all patients. SPET brain perfusion imaging was performed after the intravenous injection of a typical dose of 740 MBq Tc-99m-HMPAO in two different days before and after the intravenous administration of 1 gr Diamox. All SPET scans were interpreted visually.

Stroop interference task and single-photon emission tomography in anorexia: A preliminary report

The aim of this preliminary study was to investigate the physiologic substrate of executive function in anorexia nervosa (AN) by assessing the relation between brain perfusion and Stroop interference task (SIT). The classical SIT test and brain single-photon emission tomography (SPET) were evaluated in 16 AN females (mean age = 23.69 +/- 8.68 years; mean body mass index [BMI] = 16.19 +/- 1.53 kg/m2). The relation between the two examinations was searched by statistical parametric mapping (SPM 99) with a height threshold of p = .001. An abnormally low or a borderline SIT value was found in 25% of patients. A significant correlation between the SIT score and brain perfusion was found in the superior frontal gyrus of both hemispheres (Brodmann's area [BA] 6 in both hemispheres and BA 8 in the right hemisphere). No correlation was found in the anterior cingulate gyrus. BA 6 and BA 8 and the anterior cingulate are believed to be the basis of both error detection and immediate correction. Activity of BA 6 and BA 8 reflects this executive task in AN patients as well, whereas the lack of correlation in the anterior cingulate may suggest its blunted activity in AN patients, similarly to what is shown in other conditions characterized by impaired executive function, such as patients with depression, patients with schizophrenia, and abstinent drug abusers. However, these findings should still be quoted as preliminary, given some limitations of the study design, such as the lack of a control group, and the unfeasibility of controlling some relevant confounding variables, such as psychiatric comorbidity, medication, and the time interval between examinations, mainly deriving from the relatively few patients studied.