Brain Perfusion Single-photon Emission Research Articles

Tc-99m ECD brain perfusion single-photon emission computed tomography in Parry–Romberg syndrome

We report a 15-year-old girl referred to our department for a brain perfusion study with a diagnosis of Parry–Romberg syndrome with left hemifacial atrophy and left enophthalmos. In the presence of a normal magnetic resonance imaging, Tc-99m ECD brain perfusion revealed left temporal lobe hypoperfusion with preserved perfusion in rest of the cortical and subcortical regions and both cerebellar hemispheres.

Preoperative Cerebral Oxygen Extraction Fraction Imaging Generated from 7T MR Quantitative Susceptibility Mapping Predicts Development of Cerebral Hyperperfusion following Carotid Endarterectomy

Preoperative hemodynamic impairment in the affected cerebral hemisphere is associated with the development of cerebral hyperperfusion following carotid endarterectomy. Cerebral oxygen extraction fraction images generated from 7T MR quantitative susceptibility mapping correlate with oxygen extraction fraction images on positron-emission tomography. The present study aimed to determine whether preoperative oxygen extraction fraction imaging generated from 7T MR quantitative susceptibility mapping could identify patients at risk for cerebral hyperperfusion following carotid endarterectomy. Seventy-seven patients with unilateral internal carotid artery stenosis (≥70%) underwent preoperative 3D T2*-weighted imaging using a multiple dipole-inversion algorithm with a 7T MR imager. Quantitative susceptibility mapping images were then obtained, and oxygen extraction fraction maps were generated. Quantitative brain perfusion single-photon emission CT was also performed before and immediately after carotid endarterectomy. ROIs were automatically placed in the bilateral middle cerebral artery territories in all images using a 3D stereotactic ROI template, and affected-to-contralateral ratios in the ROIs were calculated on quantitative susceptibility mapping-oxygen extraction fraction images. Ten patients (13%) showed post-carotid endarterectomy hyperperfusion (cerebral blood flow increases of ≥100% compared with preoperative values in the ROIs on brain perfusion SPECT). Multivariate analysis showed that a high quantitative susceptibility mapping-oxygen extraction fraction ratio was significantly associated with the development of post-carotid endarterectomy hyperperfusion (95% confidence interval, 33.5-249.7; P = .002). Sensitivity, specificity, and positive- and negative-predictive values of the quantitative susceptibility mapping-oxygen extraction fraction ratio for the prediction of the development of post-carotid endarterectomy hyperperfusion were 90%, 84%, 45%, and 98%, respectively. Preoperative oxygen extraction fraction imaging generated from 7T MR quantitative susceptibility mapping identifies patients at risk for cerebral hyperperfusion following carotid endarterectomy.

Effect of resolution recovery using graph plots on regional cerebral blood flow in healthy volunteers.

We evaluated the effect of resolution recovery (RR) using graph plots on regional cerebral blood flow (rCBF) in brain perfusion single-photon emission computed tomography (SPECT) images derived from healthy volunteers and patients diagnosed with probable Alzheimer's disease. We acquired brain perfusion SPECT images with scatter correction (SC), computed tomography-based attenuation correction (CTAC), and RR from a three-dimensional brain phantom and from healthy volunteers. We then compared contrast-to-noise ratio, count density ratios, increase maps, and rCBF using statistical parametric mapping 8. Regional brain counts were significantly increased from 20-24% with SC, CTAC, and RR compared with SC and CTAC. Mean CBF in healthy volunteers was 42.5±5.4mL/100g/min. Average rCBF determined using SC, CTAC and RR increased 7.5, 2.0, and 3.7% at the thalamus, posterior cingulate, and whole brain, respectively, compared with SC and CTAC. Resolution recovery caused variations in normal rCBF because counts increased in cerebral regions.

4D Flow MR Imaging of Ophthalmic Artery Flow in Patients with Internal Carotid Artery Stenosis

Background and Purpose:To assess the clinical feasibility of time-resolved 3D phase contrast (4D Flow) MRI assessment of the ophthalmic artery (OphA) flow in patients with internal carotid artery stenosis (ICS).Materials and Methods:Twenty-one consecutive patients with unilateral ICS were recruited. 4D Flow MRI and acetazolamide-stress brain perfusion single photon emission computed tomography (SPECT) were performed. The flow direction on the affected-side OphA was categorized into native flow (anterograde or unclear) and non-native flow (retrograde flow) based on 4D Flow MRI. In the affected-side middle cerebral artery (MCA) territory, the ratio of rest cerebral blood flow to normal control (RCBFMCA) and cerebral vascular reserve (CVRMCA) were calculated from SPECT dataset. High-risk patients were defined based on the previous large cohort study (RCBFMCA < 80% and CVRMCA < 10%).Results:Eleven patients had native OphA flow (4 anterograde, 7 unclear) and the remaining 10 had non-native OphA flow. RCBFMCA and CVRMCA each were significantly lower in non-native flow group (84.9 ± 18.9% vs. 69.8 ± 7.3%, P < 0.05; 36.4 ± 20.6% vs. 17.0 ± 15.0%, P < 0.05). Four patients in the non-native flow group and none in the native flow group were confirmed as high-risk (Sensitivity/Specificity, 1.00/0.65).Conclusion:The 6 min standard 4D Flow MRI assessment of OphA in patients with ICS can predict intracranial hemodynamic impairment.

The usefulness of combined brain perfusion single-photon emission computed tomography, Dopamine-transporter single-photon emission computed tomography, and 123 I-metaiodobenzylguanidine myocardial scintigraphy for the diagnosis of dementia with Lewy bodies.

Current diagnostic criteria recommend neuroimaging as a diagnostic support tool for the clinical diagnosis of dementia with Lewy bodies (DLB). Because DLB causes characteristic impairments and disabilities, such as neuroleptic hypersensitivity, which may significantly increase morbidity and mortality, its prompt and correct diagnosis is very important. The aim of this study was to evaluate the extent to which diagnostic accuracy can be increased by using different combinations of brain perfusion single-photon emission computed tomography (bp-SPECT), 123 I-metaiodobenzylguanidine myocardial scintigraphy (MIBG scintigraphy), and DAT-SPECT. Taking finances and patient burden into consideration, we compared the tests to determine priority. Thirty-four patients with probable DLB (75.0 ± 8.3 years old; 14 men, 20 women) underwent bp-SPECT, MIBG scintigraphy, and DAT-SPECT. Our comparison of three functional imaging techniques indicated that MIBG scintigraphy (79%) and Dopamine-transporter (DAT) SPECT (79%) had better sensitivity for characteristic abnormalities in DLB than bp-SPECT (53%). The combination of the three modalities could increase sensitivity for diagnosis of DLB to 100%. Additionally, the ratio of patients with rapid eye movement sleep behaviour disorder was significantly higher in the positive finding group on MIBG scintigraphy than in the negative finding group. In terms of stand-alone diagnostic means, priority should be placed on MIBG scintigraphy or DAT-SPECT for the diagnosis of DLB. However, our results suggest that the combination of bp-SPECT, MIBG scintigraphy, and DAT-SPECT increased the accuracy of the clinical diagnosis of DLB.

Diagnosis of dementia with Lewy bodies: can 123I-IMP and 123I-MIBG scintigraphy yield new core features?

Since the clinical symptoms of different types of dementia frequently overlap, especially in the earlier stages at onset, it is difficult to distinguish dementia with Lewy bodies (DLB) from other neurodegenerative dementias based on their clinical manifestations alone. Nuclear medicine imaging has been reported as a high-value index for the objective evaluation and diagnosis of DLB. The aim of this study was to evaluate whether nuclear medicine imaging findings may yield core features to be added to the diagnosis of DLB. We enrolled 332 patients with suspected DLB. All were evaluated by both 123I-metaiodobenzylguanidine (123I-MIBG) myocardial scintigraphy and 123I-labelled N-isopropyl-p-iodoamphetamine (123I-IMP). brain perfusion single-photon emission CT. The final clinical diagnosis indicated probable DLB in 92 patients (40 males, 52 females; mean age ± standard deviation, 77.4 ± 6.4 years; range, 56-89 years); 240 patients (98 males, 142 females; mean age, 75.5 ± 9.0 years; range, 70-87 years) were recorded as being without DLB. The accepted core features used for clinical evaluations were fluctuating cognition, visual hallucinations and Parkinsonism. The nuclear medicine evaluation indices were the severity score of cerebral blood flow on 123I-IMP scintigraphs of the posterior cingulate and praecuneus and a reduction in the blood flow in the occipital lobe. For 123I-MIBG evaluation, we recorded the early and delayed heart-to-mediastinum (H/M) ratios and the washout rate. Univariate and multivariate analyses of fluctuating cognition, visual hallucinations, Parkinsonism and early H/M ratio in patients with probable and without DLB revealed significant differences. Parameters based on 123I-IMP studies did not show any significant differences by multivariate analysis. The area under the curve for the early H/M ratio was 0.918; for fluctuating cognition, visual hallucinations and Parkinsonism, it was 0.693, 0.760 and 0.611, respectively, by receiver-operating characteristic analysis. The early H/M ratio of <2.0 on 123I-MIBG scintigraphs was of the highest diagnostic accuracy. The sensitivity, specificity and accuracy for the diagnosis of probable DLB were 82.4%, 96.3% and 92.5%, respectively. The early H/M ratio obtained by 123I-MIBG myocardial scintigraphy can serve as a reliable diagnostic index for the core clinical features of DLB. It can be used for the early diagnosis and treatment of DLB. Advances in knowledge: 123I-MIBG myocardial scintigraphy performed at the initial clinical examination can facilitate the early identification or exclusion of DLB and the early H/M ratio may be a diagnostic biomarker for DLB.

55歳で全身痙攣発作を来し，特徴的な頭部画像所見からSturge-Weber症候群III型と診断した1例

A 55-year-old man with no mental retardation had presented a history of frequent transient clumsiness of his right upper and lower extremities for about 20 years. He was admitted to a general hospital with weakness of right side of the body, and first-ever generalized seizure attack occurred the next day. Brain CT showed calcification in the left cerebral cortices. So he was referred to our hospital. On neurological examination, he had mild clumsiness of his right upper limb and right pyramidal tract sign. He had neither facial port-wine stain nor glaucoma. The blood test and cerebrospinal fluid analysis were unremarkable. Electroencephalogram showed slowing and reduction of activity at the left frontal and parietal areas with no epileptic activities. Brain CT showed "tram-track calcification" and lobar atrophy in the left fronto-parietal cortices. Susceptibility weighted imaging (SWI) on MRI revealed enlarged transmedullary veins in the left periventricular white matter and low intensity lesions along the cortical gyri. Post gadolinium fluid-attenuated inversion recovery imaging (FLAIR-Gd) showed leptomeningeal enhancement in the left fronto-parietal lobes more extensively than those by post gadolinium T1-weighted image. Brain perfusion single photon emission computed tomography with a technetium-99m-ethyl cysteinate dimer (99mTc-ECD SPECT) revealed hypoperfusion in the fronto-parietal lobes. These clinical and neuroimaging findings were compatible with type III Sturge-Weber syndrome (SWS). His condition was improved after treatment with oral levetiracetam (1,000 mg daily). Although adult-onset type III SWS is very rare, it is important to perform SWI and post-contrast FLAIR for assessing leptomeningeal angioma in patients with seizure with focal cortical calcification even if they have no facial nevus.

Neural Correlates of Motor Recovery Measured by SPECT at Six Months After Basal Ganglia Stroke.

ObjectiveTo investigate neural correlates associated with recovery of motor function over 6 months in patients with basal ganglia (BG) stroke using acetazolamide (ACZ) stress brain-perfusion single-photon emission computed tomography (SPECT).MethodsMedical records of 22 patients presenting first-ever BG stroke were retrospectively reviewed. Regional cerebral blood flow (CBF) and cerebrovascular reserve (CVR) were measured for 9 regions in each cerebral hemisphere (primary motor cortex, supplementary motor area, premotor cortex, prefrontal cortex, temporal lobe, parietal lobe, occipital lobe, BG, and thalamus). The Fugl-Meyer Assessment (FMA) motor score was used to assess motor function.ResultsAfter ACZ injection, CBF of all regions of interest (ROIs) increased compared with baseline. Baseline CBF of all ROIs was not significantly correlated with changes in FMA upper or lower motor score. However, multivariate analysis revealed CVR was significantly associated with change in FMA upper score in the ipsilateral primary motor cortex (R2=0.216, p=0.017), the ipsilateral parietal lobe (R2=0.135, p=0.029), and the contralateral primary motor cortex (R2=0.210, p=0.041).ConclusionCVR in the bilateral primary motor cortex and ipsilateral parietal lobe was associated with restoration of upper motor function 6 months after BG stroke. SPECT is a readily available imaging modality useful in studying brain residual function in patients with BG stroke.

The cingulate island sign within early Alzheimer’s disease-specific hypoperfusion volumes of interest is useful for differentiating Alzheimer’s disease from dementia with Lewy bodies

BackgroundIn addition to occipital hypoperfusion, preserved metabolism of the posterior cingulate gyri (PCG) relative to the precunei is known as the cingulate island sign (CIS) in the patients with dementia with Lewy bodies (DLB). CIS has been detected using [18F]fluorodeoxyglucose positron emission tomography but not using brain perfusion single-photon emission computed tomography (SPECT). The purpose of this study was to optimize brain perfusion SPECT to enable differentiation of DLB from Alzheimer’s disease (AD) using CIS and occipital hypoperfusion.Eighteen patients with probable DLB and 17 age-matched Pittsburgh compound B-positive patients with AD underwent technetium-99m ethyl cysteinate dimer SPECT. SPECT Z-score maps were generated using the easy Z-score imaging system (eZIS) analysis software (Matsuda H, Mizumura S, Nagao T, Ota T, Iizuka T, Nemoto K, Takemura N, Arai H, Homma A, AJNR Am J Neuroradiol 28(4):731–6, 2007), which included volumes of interest (VOIs) in which a group comparison between patients with AD and cognitively normal subjects revealed significant relative hypoperfusion. We used the Montreal Neurological Institute (MNI) space anatomical border to divide the bilateral PCG to precunei VOIs into two parts, the PCG and precunei. Z-scores in the PCG, precunei, and occipital areas and ratios were analysed and compared with receiver operating characteristic (ROC) curve analyses.ResultsThe largest area under the curve (AUC) value for use in differentiating DLB from AD with the ratio of PCG to medial occipital was 0.87; the accuracy, sensitivity, and specificity were 85.7, 88.9, and 82.4 %, respectively. The AUC with the ratio of PCG to the precuneus was smaller, and it was 0.85, though no significant difference was observed between these two AUCs.ConclusionsThe Z-score ratio of the PCG within the early-AD-specific VOI to medial-occipital area is clinically useful in discriminating demented patients with DLB from those with AD.Electronic supplementary materialThe online version of this article (doi:10.1186/s13550-016-0224-5) contains supplementary material, which is available to authorized users.

Effect of Deep Brain Stimulation on Regional Cerebral Blood Flow in Patients with Medically Refractory Tourette Syndrome.

In this study, alterations in brain perfusion have been investigated in patients with Tourette syndrome (TS) compared with control subjects. In addition, we investigated the effects of deep brain stimulation (DBS) in both globus pallidus internus (GPi) and centromedian-parafascicular/ventralis oralis internus nuclei of the thalamus (CM/Voi) and sham (SHAM) stimulation on cerebral blood flow. In a prospective controlled, randomized, double-blind setting, five severely affected adult patients with TS with predominant motor or vocal tics (mean total tic score on the Yale Global Tic Severity Scale: 39) underwent serial brain perfusion single photon emission computed tomography with 99mTc-ECD. Results were compared with data from six age-matched control subjects. All patients were investigated at four different time points: once before DBS implantation (preOP) and three times postoperatively. Postoperative scans were performed in a randomized order, each after 3 months of either GPi, CM/Voi, or SHAM stimulation. At each investigation, patients were injected at rest while awake, but scanned during anesthesia. This procedure ensured that neither anesthesia nor movement artifacts influenced our results. Control subjects were investigated only once at baseline (without DBS or anesthesia). At baseline, cerebral blood flow was significantly reduced in patients with TS (preOP) compared with controls in the central region, frontal, and parietal lobe, specifically in Brodmann areas 1, 4–9, 30, 31, and 40. Significantly increased perfusion was found in the cerebellum. When comparing SHAM stimulation to preOP condition, we found significantly decreased perfusion in basal ganglia and thalamus, but increased perfusion in different parts of the frontal cortex. Compared with SHAM condition both GPi and thalamic stimulation resulted in a significant decrease in cerebral blood flow in basal ganglia and cerebellum, while perfusion in the frontal cortex was significantly increased. Our results provide substantial evidence that, in TS, brain perfusion is altered in the frontal cortex and the cerebellum and that these changes can be reversed by both GPi and CM/Voi DBS.

Brain perfusion imaging with voxel-based analysis in secondary progressive multiple sclerosis patients with a moderate to severe stage of disease: a boon for the workforce.

BackgroundThe present study was carried out to evaluate cerebral perfusion in multiple sclerosis (MS) patients with a moderate to severe stage of disease. Some patients underwent hyperbaric oxygen therapy (HBOT) and brain perfusion between before and after that was compared.MethodsWe retrospectively reviewed 25 secondary progressive (SP)-MS patients from the hospital database. Neurological disability evaluated by Expanded Disability Status Scale Score (EDSS). Brain perfusion was performed by (99 m) Tc-labeled bicisate (ECD) brain SPECT and the data were compared using statistical parametric mapping (SPM). In total, 16 patients underwent HBOT. Before HBOT and at the end of 20 sessions of oxygen treatment, 99mTc-ECD brain perfusion single photon emission computed tomography (SPECT) was performed again then the results were evaluated and compared. Brain perfusion was performed by (99 m) Tc-labeled bicisate (ECD) brain SPECT and the data were compared using statistical parametric mapping (SPM).ResultsA total of 25 SP-MS patients, 14 females (56 %) and 11 males (44 %) with a mean age of 38.92 ± 11.28 years included in the study. The mean disease duration was 8.70 ± 5.30 years. Of the 25 patients, 2 (8 %) had a normal SPECT and 23 (92 %) had abnormal brain perfusion SPECT studies. The study showed a significant association between severity of perfusion impairment with disease duration and also with EDSS (P <0.05). There was a significant improvement in pre- and post-treatment perfusion scans (P <0.05), but this did not demonstrate a significant improvement in the clinical subjective and objective evaluation of patients (P >0.05).ConclusionsThis study depicted decreased cerebral perfusion in SP-MS patients with a moderate to severe disability score and its association with clinical parameters. Because of its accessibility, rather low price, practical ease, and being objective quantitative information, brain perfusion SPECT can be complementing to other diagnostic modalities such as MRI and clinical examinations in disease surveillance and monitoring. The literature on this important issue is extremely scarce, and follow up studies are required to assess these preliminary results.

Cerebrovascular Events During Pregnancy and Puerperium Resulting from Preexisting Moyamoya Disease: Determining the Risk of Ischemic Events Based on Hemodynamic Status Assessment Using Brain Perfusion Single-Photon Emission Computed Tomography

The purposes of this study were to review the cerebrovascular events (CVE) during pregnancy and puerperium in adults with moyamoya disease (MMD) and to evaluate its risk factors. We reviewed electronic medical records on 141 pregnancies in 71 women diagnosed with MMD and this study included only 27 pregnancies (23 patients) diagnosed with MMD before pregnancy. Basal and acetazolamide-stress brain perfusion single-photon emission computed tomography (SPECT) was conducted for 40 hemispheres in 21 pregnancies within 1 year of the gestational period, ranging from 22 months before delivery to 12 months after delivery for evaluation of the hemodynamic status of the patients to devise the MMD treatment strategy. Twelve pregnancies (44.4%) showed CVE during pregnancy or puerperium in the group diagnosed with MMD before pregnancy. All the 12 CVE were ischemic, without any hemorrhagic events. A decreased cerebral vascular reserve capacity (CVRC) on stress SPECT was observed in 25 (62.5%) of the 40 hemispheres, and 18 of these 25 hemispheres showed TIA. In contrast, only 2 of 15 hemispheres which revealed normal CVRC on stress SPECT showed TIA. Overall, a decreased CVRC on stress SPECT imaging was statistically associated with development of CVE (P < 0.001). Furthermore, the clinical type of MMD was also regarded as predictive factor for CVE in this study. Especially, ischemic type MMD revealed a statistical association with the development of CVE (P= 0.014, odds ratio= 16.50). Assessment of cerebral hemodynamic status with stress SPECT may predict CVE during pregnancy and puerperium.

Preoperative prediction of cerebral hyperperfusion after carotid endarterectomy using middle cerebral artery signal intensity in 1.5-tesla magnetic resonance angiography followed by cerebrovascular reactivity to acetazolamide using brain perfusion single-photon emission computed tomography

Objective: The purpose of the present study was to determine whether the signal intensity of the middle cerebral artery (MCA) on preoperative 1.5-T magnetic resonance angiography (MRA) could identify patients at risk for hyperperfusion following carotid endarterectomy (CEA) as a clinical screening test and whether an additional measurement of preoperative cerebrovascular reactivity (CVR) to acetazolamide on brain perfusion single-photon emission computed tomography (SPECT) could increase the predictive accuracy for the development of hyperperfusion.Methods: In 301 patients, the signal intensity of the MCA ipsilateral to CEA on MRA was preoperatively graded according to the ability to visualize the MCA. For patients with reduced MCA signal intensity on the MRA study, CVR to acetazolamide was subsequently assessed using brain perfusion SPECT. Cerebral hyperperfusion was determined intraoperatively using transcranial regional cerebral oxygen saturation monitoring with near-infrared spectroscopy.Results: Preoperative reduced MCA signal intensity was significantly associated with the development of cerebral hyperperfusion (95% CI, 1.188-3.965; p = 0.0352). While the sensitivity and negative predictive value were 100% both for the preoperative MCA signal intensity alone and in combination with subsequent preoperative CVR to acetazolamide, the specificity and positive predictive value were significantly greater for the latter than for the former (p < 0.05).Conclusions: Signal intensity of the MCA on preoperative 1.5-T MRA identifies patients at risk for hyperperfusion following CEA as a clinical screening test. An additional measurement of preoperative CVR to acetazolamide increases the predictive accuracy for the development of hyperperfusion.

Psychosis in Machado-Joseph Disease: Clinical Correlates, Pathophysiological Discussion, and Functional Brain Imaging. Expanding the Cerebellar Cognitive Affective Syndrome.

Machado-Joseph disease (MJD) is the most common spinocerebellar ataxia worldwide with a broad range of clinical manifestations, but psychotic symptoms were not previously characterized. We investigated the psychiatric manifestations of a large cohort of Brazilian patients with MJD in an attempt to characterize the presence of psychotic symptoms. We evaluated 112 patients with clinical and molecular diagnosis of MJD from February 2008 to November 2013. Patients with psychotic symptoms were referred to psychiatric evaluation and brain perfusion single-photon emission computed tomography (SPECT) analysis. A specific scale-Positive and Negative Syndrome Scale (PANSS)-was used to characterize psychotic symptoms in MJD patients. We also performed an autopsy from one of the patients with MJD and psychotic symptoms. Five patients presented psychotic symptoms. Patients with psychotic symptoms were older and had a late onset of the disease (p < 0.05). SPECT results showed that MJD patients had significant regional cerebral blood flow (rCBF) decrease in the cerebellum bilaterally and vermis compared with healthy subjects. No significant rCBF differences were found in patients without psychotic symptoms compared to patients with psychotic symptoms. The pathological description of a patient with MJD and psychotic symptoms revealed severe loss of neuron bodies in the dentate nucleus and substantia nigra. MJD patients with a late onset of the disease and older ones are at risk to develop psychotic symptoms during the disease progression. These clinical findings may be markers for an underlying cortical-cerebellar disconnection or degeneration of specific cortical and subcortical regions that may characterize the cerebellar cognitive affective syndrome.

Relationship between white matter lesions and regional cerebral blood flow changes during longitudinal follow up in Alzheimer's disease.

The aim of the present study was to evaluate the relationship between baseline white matter lesions (WML) and changes in regional cerebral blood flow during longitudinal follow up of patients with Alzheimer's disease (AD). A total of 38 patients with AD were included in the study (16 men, 22 women; mean age 77.8 years). All patients were evaluated using the Mini-Mental State Examination and brain perfusion single-photon emission computed tomography at baseline with an approximately 2-year follow up. The patients were divided into two subgroups according to the presence of WML on magnetic resonance imaging. Single-photon emission computed tomography data were analyzed using a voxel-by-voxel group analysis with Statistical Parametric Mapping 8 and region of interest analysis using FineSRT. Changes in Mini-Mental State Examination scores and regional cerebral blood flow were analyzed using the Wilcoxon signed-rank test. Mean Mini-Mental State Examination scores in AD patients with WML significantly decreased from 19.4 ± 4.8 to 15.5 ± 6.5 (P = 0.003). Statistical Parametric Mapping 8 and FineSRT analysis showed more severe and widespread regional cerebral blood flow reduction, mainly in the frontal and mesial temporal regions in AD patients with WML compared with those without WML. Baseline WML could predict a rapid progression of cognitive and brain functional impairment during longitudinal follow up in AD. Geriatr Gerontol Int 2016; 16: 836-842.

Post-carotid endarterectomy changes in cerebral glucose metabolism on (18)F-fluorodeoxyglucose positron emission tomography associated with postoperative improvement or impairment in cognitive function.

Cognitive function is often improved or impaired after carotid endarterectomy (CEA) for patients with cerebral hemodynamic impairment. Cerebral glucose metabolism measured using positron emission tomography (PET) with (18)F-fluorodeoxyglucose (FDG) correlates with cognitive function in patients with neurodegenerative diseases. The present study aimed to determine whether postoperative changes in cerebral glucose metabolism are associated with cognitive changes after CEA. In patients who were scheduled to undergo CEA for ipsilateral internal carotid artery (ICA) stenosis (≥ 70% narrowing), cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) to acetazolamide were assessed preoperatively using brain perfusion single-photon emission computed tomography (SPECT). CBF measurement using SPECT was also performed immediately after CEA. For patients with reduced preoperative CVR to acetazolamide in the cerebral hemisphere ipsilateral to surgery, cerebral glucose metabolism was assessed using FDG-PET before surgery and 3 months after surgery and was analyzed using 3D stereotactic surface projection. Neuropsychological testing was also performed preoperatively and 3 months postoperatively. Twenty-two patients with reduced preoperative CVR to acetazolamide successfully underwent FDG-PET studies and neuropsychological testing before and after CEA. Seven, 9, and 6 patients were defined as showing improved, unchanged, and impaired postoperative cognition, respectively, based on the neuropsychological assessments. The cortical area with increased postoperative glucose metabolism was greater in patients with improved postoperative cognition than in those with unchanged (p < 0.001) or impaired (p < 0.001) postoperative cognition. The cortical area with decreased postoperative glucose metabolism was greater in patients with impaired postoperative cognition than in those with improved (p < 0.001) or unchanged (p < 0.001) postoperative cognition. All 7 patients with improved cognition exhibited postoperative hemispheric increases in glucose metabolism, while 5 of the 6 patients with impaired cognition exhibited postoperative hemispheric decreases in glucose metabolism. Brain perfusion SPECT revealed that the latter 6 patients experienced postoperative cerebral hyperperfusion, and 2 of the 6 patients exhibited cerebral hyperperfusion syndrome. The cortical area with decreased postoperative glucose metabolism in these 2 patients was greater than that in other patients. Postoperative changes in cerebral glucose metabolism, as measured using FDG-PET, are associated with cognitive improvement and impairment after CEA.

Evaluation of Regional Cerebral Blood Flow in Alzheimer's Disease Patients with Subclinical Hypothyroidism

Background: This study examined regional cerebral blood flow (rCBF) in Alzheimer's disease (AD) patients with and without subclinical hypothyroidism (SCH). Methods: Eleven AD patients with SCH and 141 AD patients without SCH underwent brain perfusion single photon emission computed tomography (SPECT). The SPECT data were analyzed by statistical parametric mapping (SPM8) and FineSRT. Results: AD patients with SCH showed a significantly decreased rCBF mainly in the temporal lobe and thalamus, whereas those without SCH showed a significantly decreased rCBF in the parietotemporal lobe and cingulate gyrus as well as the frontal lobe. Conclusion: Our findings suggest that SCH may affect cerebral perfusion in regions associated with the memory function.

Perfusion single photon emission computed tomography in a mouse model of neurofibromatosis type 1: towards a biomarker of neurologic deficits.

Neurofibromatosis type 1 (NF1) is a single-gene disorder affecting neurologic function in humans. The NF1+/- mouse model with germline mutation of the NF1 gene presents with deficits in learning, attention, and motor coordination, very similar to NF1 patients. The present study performed brain perfusion single-photon emission computed tomography (SPECT) in NF1+/- mice to identify possible perfusion differences as surrogate marker for altered cerebral activity in NF1. Cerebral perfusion was measured with hexamethyl-propyleneamine oxime (HMPAO) SPECT in NF1+/- mice and their wild-type littermates longitudinally at juvenile age and at young adulthood. Histology and immunohistochemistry were performed to test for structural changes. There was increased HMPAO uptake in NF1 mice in the amygdala at juvenile age, which reduced to normal levels at young adulthood. There was no genotype effect on thalamic HMPAO uptake, which was confirmed by ex vivo measurements of F-18-fluorodeoxyglucose uptake in the thalamus. Morphologic analyses showed no major structural abnormalities. However, there was some evidence of increased density of microglial somata in the amygdala of NF1-deficient mice. In conclusion, there is evidence of increased perfusion and increased density of microglia in juvenile NF1 mice specifically in the amygdala, both of which might be associated with altered synaptic plasticity and, therefore, with cognitive deficits in NF1.

Does preoperative measurement of cerebral blood flow with acetazolamide challenge in addition to preoperative measurement of cerebral blood flow at the resting state increase the predictive accuracy of development of cerebral hyperperfusion after carotid endarterectomy? Results from 500 cases with brain perfusion single-photon emission computed tomography study.

The purpose of the present study was to determine whether preoperative measurement of cerebral blood flow (CBF) with acetazolamide in addition to preoperative measurement of CBF at the resting state increases the predictive accuracy of development of cerebral hyperperfusion after carotid endarterectomy (CEA). CBF at the resting state and cerebrovascular reactivity (CVR) to acetazolamide were quantitatively assessed using N-isopropyl-p-[123I]-iodoamphetamine (IMP)-autoradiography method with single-photon emission computed tomography (SPECT) before CEA in 500 patients with ipsilateral internal carotid artery stenosis (≥ 70%). CBF measurement using 123I-IMP SPECT was also performed immediately and 3 days after CEA. A region of interest (ROI) was automatically placed in the middle cerebral artery territory in the affected cerebral hemisphere using a three-dimensional stereotactic ROI template. Preoperative decreases in CBF at the resting state [95% confidence intervals (CIs), 0.855 to 0.967; P = 0.0023] and preoperative decreases in CVR to acetazolamide (95% CIs, 0.844 to 0.912; P < 0.0001) were significant independent predictors of post-CEA hyperperfusion. The area under the receiver operating characteristic curve for prediction of the development of post-CEA hyperperfusion was significantly greater for CVR to acetazolamide than for CBF at the resting state (difference between areas, 0.173; P < 0.0001). Sensitivity, specificity, and positive- and negative-predictive values for the prediction of the development of post-CEA hyperperfusion were significantly greater for CVR to acetazolamide than for CBF at the resting state (P < 0.05, respectively). The present study demonstrated that preoperative measurement of CBF with acetazolamide in addition to preoperative measurement of CBF at the resting state increases the predictive accuracy of the development of post-CEA hyperperfusion.

Obstructive carotid and/or intracranial artery disease rarely affects the incidence of haemodynamic ischaemic stroke during cardiac surgery: a study on brain perfusion single-photon emission computed tomography with acetazolamide.

Ischaemic stroke is a major complication of cardiac surgery. The optimal strategies for operating on patients with obstructive carotid and/or intracranial artery disease (CIAD) are controversial. We aimed to clarify whether single-photon emission computed tomography (SPECT) with acetazolamide, to quantify the cerebral perfusion reserve, could predict the risk of haemodynamic ischaemic stroke during cardiac surgery. The incidence of stroke related to obstructive CIAD and the corresponding autoregulatory reserve were prospectively assessed in 514 consecutive patients who underwent elective cardiac surgery with cardiopulmonary bypass (n = 484) and off-pump coronary artery bypass grafting (n = 30) between 2009 and 2013. Preoperative cerebral blood flow and its reactivity to acetazolamide were quantitatively determined in patients (n = 88) with obstructive CIAD, diagnosed by carotid ultrasonography and/or magnetic resonance angiography. An impaired cerebral perfusion reserve was identified in 1 (1.1%) of the 88 patients. This patient underwent prophylactic superficial temporal artery to middle cerebral artery anastomosis 1 month before coronary artery bypass surgery. Subsequently, the patient underwent conventional coronary artery bypass surgery, without experiencing perioperative stroke. Seven (1.4%) patients died in-hospital mortality and 5 (1.0%) experienced perioperative stroke. However, no patients experienced perioperative haemodynamic ischaemic stroke. It is unusual for CIAD to affect the incidence of haemodynamic ischaemic stroke during cardiac surgery. Brain perfusion SPECT with acetazolamide is effective for narrowing down patients at high risk of ischaemic stroke during cardiac surgery. Meanwhile, the application of brain perfusion single-photon emission tomography should be confined only to patients with obstructive CIAD because it is an expensive examination tool.