Cerebral Perfusion SPECT Research Articles

Diagnostic approach with Z-score mapping to reduce artifacts caused by cerebral atrophy in regional CBF assessment of mild cognitive impairment (MCI) and Alzheimer's disease by [99mTc]-ECD and SPECT

PurposeThe aim of this study was to develop a novel approach that enhanced diagnostic accuracy in the diagnosis of mild cognitive impairment (MCI) and early Alzheimer's disease (AD) using cerebral perfusion SPECT by minimizing artifacts caused by cerebral atrophy.Materials and methods[99mTc]-ECD and SPECT studies were performed on 15 cognitively normal patients, 40 patients with MCI, and 16 patients with AD. SPECT images were compared using SPM. The atrophy correction method was incorporated to reduce artifacts through the MRI masking procedure. Regional Z-score, percent extent, and atrophy correction rate were obtained and compared. The Z-score mapping program was structured as a single package that ran semi-automatically.ResultsThe method significantly reduced regional Z-score in most regions, leading to improved estimates. The mean atrophy correction rate ranged from 10.4 to 12.0%. In MCI and AD, the convexities of the frontal and parietal lobes and the posterior medial cerebrum were particularly sensitive to cerebral atrophy, and the Z-scores were overestimated, whereas the posterior cingulate cortex and the cerebellum were less sensitive. The diagnostic accuracy for MCI increased from 67 to 69% and for AD from 78 to 82%.ConclusionThe proposed approach provided more precise Z-scores with less over- or underestimation, artifacts, and improved diagnostic accuracy, being recommended for clinical studies.

Detection of Alzheimer's disease using ECD SPECT images by transfer learning from FDG PET.

To develop a practical method to rapidly utilize a deep learning model to automatically extract image features based on a small number of SPECT brain perfusion images in general clinics to objectively evaluate Alzheimer's disease (AD). For the properties of low cost and convenient access in general clinics, Tc-99-ECD SPECT imaging data in brain perfusion detection was used in this study for AD detection. Two-stage transfer learning based on the Inception v3 network model was performed using the ImageNet dataset and ADNI database. To improve training accuracy, the three-dimensional image was reorganized into three sets of two-dimensional images for data augmentation and ensemble learning. The effect of pre-training parameters for Tc-99m-ECD SPECT image to distinguish AD from normal cognition (NC) was investigated, as well as the effect of the sample size of F-18-FDG PET images used in pre-training. The same model was also fine-tuned for the prediction of the MMSE score from the Tc-99m-ECD SPECT image. The AUC values of w/wo pre-training parameters for Tc-99m-ECD SPECT image to distinguish AD from NC were 0.86 and 0.90. The sensitivity, specificity, precision, accuracy, and F1 score were 100%, 75%, 76%, 86%, and 86%, respectively for the training model with 1000 cases of F-18-FDG PET image for pre-training. The AUC values for various sample sizes of the training dataset (100, 200, 400, 800, 1000 cases) for pre-training were 0.86, 0.91, 0.95, 0.97, and 0.97. Regardless of the pre-training condition ECD dataset used, the AUC value was greater than 0.85. Finally, predicting cognitive scores and MMSE scores correlated (R2 = 0.7072). With the ADNI pre-trained model, the sensitivity and accuracy of the proposed deep learning model using SPECT ECD perfusion images to differentiate AD from NC were increased by approximately 30% and 10%, respectively. Our study indicated that the model trained on PET FDG metabolic imaging for the same disease could be transferred to a small sample of SPECT cerebral perfusion images. This model will contribute to the practicality of SPECT cerebral perfusion images using deep learning technology to objectively recognize AD.

Brain SPECT perfusion and PET metabolism as discordant biomarkers in major depressive disorder

BackgroundBrain SPECT perfusion and PET metabolism have been, most often interchangeably, proposed to study the underlying pathological process in major depressive disorder (MDD). The objective of this study was to specify similarities and inconsistencies between these two biomarkers according to global characteristics of the disease. We conducted a retrospective study in 16 patients suffering from treatment-resistant MDD who underwent, during the same current episode, a cerebral perfusion SPECT with 99mTc-HMPAO and a metabolic PET with 18F-FDG. Whole-brain voxel-based SPM(T) maps were generated in correlation with the number of depressive episodes and in correlation with the depression duration, separately for the two exams (p-voxel < 0.001 uncorrected, k > 20).ResultsNo significant correlations were found between brain metabolism and either the number of depressive episodes or the duration of the disease, even at an uncorrected p-voxel < 0.005. On the other hand, the increased number of depressive episodes was correlated with decreased perfusion of the right middle frontal cortex, the right anterior cingulum cortex, the right insula, the right medial temporal cortex and the left precuneus. The increased depression duration was correlated with decreased perfusion of the right anterior cingulum cortex.ConclusionsThis preliminary study demonstrates more significant results with brain perfusion compared with glucose metabolism in treatment-resistant MDD, highlighting the value of brain SPECT despite less favourable instrumentation detection compared to PET.

The Effect of Electroencephalography Leads on Image Quality in Cerebral Perfusion SPECT and 18F-FDG PET/CT.

Cerebral perfusion SPECT and 18F-FDG PET/CT are commonly performed diagnostic procedures for patients with epilepsy. Individuals undergoing these tests are often inpatients with electroencephalography leads. We have routinely removed these leads because of concern that they would lead to imaging artifacts. The leads would then be replaced at the conclusion of the scan. The goal of our study was to determine whether the electroencephalography leads actually do cause artifacts that can lead to erroneous scan interpretation or make the scan uninterpretable. Methods: 18F-FDG PET/CT and 99mTc-pertechnetate SPECT were performed on a 2-dimensional brain phantom. The phantom was scanned with standard leads, CT/MR-compatible leads, and no leads. The quality of the images was ranked by 3 experienced nuclear medicine physicians, who then determined whether they could differentiate each of the scans from a scan in which it was known that no leads were present. Results: No differences could be detected between scans obtained without leads and scans obtained with either set of leads. The standard electroencephalography leads did create artifacts in the CT portion of the PET/CT images, whereas the CT/MR-compatible leads did not. Conclusion: This phantom study suggests that electroencephalography leads, whether standard or CT/MR-compatible, do not need to be removed for SPECT or PET procedures. Further study evaluating the effect on actual patient scans would be of value to support this conclusion.

SPECT cerebral perfusion imaging and its quantitative analysis for the assessment of stent implantation for cerebral artery stenosis

Objective To evaluate the role of SPECT cerebral perfusion imaging in assessing the stent implantation for cerebral artery stenosis. Methods A total of 35 patients (31 males, 4 females, average age (63.9±10.8) years) with cerebral artery stenosis confirmed by DSA for cerebral artery stent implantation were retrospectively analyzed. 99Tcm-ECD cerebral perfusion imaging was performed for all patients before and after stent implantation. The images were realigned and normalized by SPM 2.0 and then analyzed by Brain Search software for quantitative analysis. The brain was automatically separated to 210 functional areas according to Talarich map. The normalized averaged counts (NAC) of each area were calculated and compared with the data of 28 health controls(8 males, 20 females, average age (35.8±9.4) years). Less than 1.96s was defined as low perfusion lesions. The NAC values before and after stent implantation were compared for classifying improved from non-improved group. The mean number of lesions and Essen stroke risk score (ESRS) were analyzed between the two groups. The mean number of lesions and postoperative improvement rate of the internal carotid artery (ICA) occlusion and stenosis were compared. Paired rank sum test, two-sample t test, two-sample rank sum test and χ2 test were used for statistical analysis. Results In 35 patients with low perfusion areas, 20 were significantly improved after stent implantation. The mean number of lesions in the improved group(34.05±14.41) was significantly higher than that in the non-improved group (22.93±17.24; t=2.067, P 0.05). The mean number of the ICA occlusion lesions (34.36±14.31) was higher than that of the ICA stenosis lesions(31.35±16.37), but the difference was not statistically significant(t=0.498, P>0.05). The improvement rate of the ICA occlusion was higher than that of the ICA stenosis (7/11 vs 10/17), but the difference was not statistically significant(P>0.05). Conclusion SPECT cerebral perfusion imaging and its quantitative analysis can evaluate the low perfusion lesions before stent implantation and predict the perfusion improvement after stent implantation. Key words: Carotid stenosis; Stents; Tomography, emission-computed, single-photon; ECD

Early detection of subjective memory impairment in Parkinson's disease using cerebral perfusion SPECT.

Cognitive dysfunction is a common feature of Parkinson's disease (PD). Recent research has focused on the detection and management of subjective memory impairment (SMI) as the stage that precedes mild cognitive impairment (MCI). Nevertheless, few clinical studies have biomarkers of SMI in PD. Therefore, this study was designed to investigate differences in perfusion brain SPECT between PD with SMI (PD+SMI) and PD without SMI (PD-SMI) to identify a potential prodromal biomarker of progression to dementia in patients with PD. In this study, 30 PD patients with SMI and 24 PD patients without SMI have been recruited. All subjects underwent perfusion brain SPECT and neuropsychological testing. Brain SPECT images were analyzed by using the SPM program and comparing between patients with PD+SMI and PD-SMI. The PD+SMI and PD-SMI groups did not differ in any neuropsychological tests, except for MMSE. Despite a significant difference in MMSE scores, all scores of both groups were in the normal range. Brain SPECT analysis of PD+SMI patients showed hypoperfusion in the frontal and inferior temporal regions, anterior cingulate and thalamus compared with PD-SMI patients. This pilot study investigated the role of decreased brain perfusion SPECT findings in PD+SMI patients compared with PD-SMI patients as a predictive biomarker of pre-dementia as the stage that precedes MCI in PD. Larger, prospective studies are warranted for further investigation of the pathophysiology of neuronal systems during cognitive decline.

Impact of 99mTc-HMPAO Brain Perfusion Scan in the Diagnosis of Hemiplegic Migraine

Hemiplegic migraine (HM) is an unusual type of migraine, with few cases reported in the literature. Unlike other types of migraine, aura HM presents accompanying motor deficit manifestations that do not last more than 24 hours. We report a 27-year-old man referred to us from the emergency department to carry out a cerebral perfusion SPECT with (99m)Tc-HMPAO. He presented with intense headache and motor weakness. The brain perfusion scan was performed before and after intravenous infusion with nimodipine and showed a significant change of cerebral blood flow, allowing early and correct diagnosis.

Fronto-striatal dysfunction in type 3 familial cortical myoclonic tremor epilepsy occurring during aging

The aim of this work is to study the cognition, progressive gait impairment, and neuroimaging findings in two patients over 65 years old of the previously described type 3 familial cortical myoclonic tremor with epilepsy (FCMTE3). We report investigations in two of these five FCMTE3 subjects over 65 and showing progressive gait disorders. They both had a pseudo-Parkinson's way of walking and visual intolerance to bright light and brightness contrast without EEG abnormalities exacerbating cortical myoclonus or triggering seizure. Case 1 had moderate gait impairment and a severe frontal syndrome. Case 2 had severe gait impairment and diffuse cognitive disorders. Both cases had cortical hypoperfusion (predominantly in the left frontal lobe) and no cerebellar abnormality on cerebral perfusion SPECT. DAT-SPECT showed dopaminergic depletion. These data indicate fronto-striatal dysfunction associated with gait impairment and cognitive disorders appearing after several decades of disease progression. This gives clues to understanding the pathogenesis and evolution of FCMTE3. Permanent myoclonic discharges or long-term valproate treatment may cause significant toxic effects on neurons (dopaminergic and frontal neurons). Further functional and molecular analyses are required in order to better understand this pathology and the consequences of chronic cortical myoclonus.

Effect of Prefiltering Cutoff Frequency and Scatter and Attenuation Corrections During Normal Database Creation for Statistical Imaging Analysis of the Brain

The present study aimed to quantify which image reconstruction conditions for normal databases and patients affect statistical brain function image analysis using an easy z score imaging system (eZIS) and 3-dimensional stereotactic surface projections (3D-SSP). We constructed normal databases based on cerebral perfusion SPECT images obtained from 15 healthy individuals. Each normal database was created with the following unique conditions: a variable Butterworth filter cutoff frequency (fc) with and without scatter and attenuation corrections. To simulate patient data, we selected 1 dataset from among those created from the 15 healthy individuals. The simulated patient data were designed to include hypoperfused regions with prespecified volumes. Using 3D-SSP and eZIS, we compared how the above processing conditions affect the distribution of SD in normal database images and the accuracy of detecting specific regions. The SD for the SPECT images increased with the fc of the Butterworth filter. The z score decreased by 30% for 3D-SSP and by 14% for eZIS, indicating that the prefilter significantly affected z scores. The accuracy of detecting the hypoperfused regions was significantly influenced by the fc; 3D-SSP decreased by 7.51%, and eZIS decreased by 55.34%. The detection accuracy with eZIS, which involves a smoothing process, was significantly decreased. The error of the area of hypoperfused regions was minimized when normal database and patient data were both corrected for scatter and attenuation. When the reconstruction conditions (fc, scatter correction, and attenuation correction) at normal database creation differed from those at patient data processing, the z scores widely underestimated the analytic results because the SD varied according to the reconstruction conditions. The accuracy of brain function image analysis can be improved by considering the reconstruction conditions and correcting for scatter and attenuation on both normal databases and patient data.

Scintigraphie cérébrale et démence à corps de Lewy

Dementia of Lewy bodies (DLB) is the second cause of degenerative dementia. There is many clinical presentation of the disease. Brain single photon computed tomography (SPECT) is a simple way to investigate routinely the cerebral blood flow. On cerebral perfusion SPECT, DLB is accompanied by diffuse cortical hypoperfusion predominantly at the posterior cortex and may affect the associative and primary visual areas in relation to neuronal loss or dysfunction. DLB patients have striatal hypofixation on cerebral neurotranmission SPECT-DaTSCAN(®), related with dopaminergic loss. Brain SPECT is useful in the differential diagnosis between DLB and other dementia.

Scintigraphie cérébrale de perfusion et troubles cognitifs d’origine vasculaire

The vascular cognitive impairment (VCI) is a heterogeneous group of various etiologies, which share a presumed vascular cause. Although the age is the most important risk factor, the cardiovascular risk factors are also involved. A relatively high proportion of these cognitive disorders could be prevented or delayed. Only the treatment of arterial hypertension is recognized as a factor in preventing vascular dementia. MRI is the examination of choice for the investigation of cerebral vascular pathology. However, this morphological imaging is insufficient and does not provide useful functional information. Perfusion brain SPECT is not widely used in the exploration of VCI. Strategies for screening VCI are not standardized and long-term studies are needed to establish the better prevention of cognitive vascular disorders. This article aims to summarize the possible benefit of cerebral perfusion SPECT in the exploration of VCI.

Comparaison des performances de l’imagerie des transporteurs dopaminergiques et de la tomoscintigraphie de perfusion cérébrale à l’HMPAO- 99mTc dans le diagnostic de maladie à corps de Lewy diffus

Dementia with Lewy bodies is the second cause of degenerative dementia. Differential diagnosis may be difficult, in spite of the emergence of standardized diagnostic criteria. Tomoscintigraphy using iodine 123-labelled FP-CIT (DaTSCAN ®) could play a role in this process. Cerebral perfusion SPECT imaging is an important step of demented patient evaluation. We compared the diagnostic performance of both of these procedures in the diagnosis of dementia with Lewy bodies. We studied 15 patients; ten DaTSCAN ® and 14 cerebral perfusion studies were performed. Clinical diagnosis at the end of follow-up was established as the diagnostic reference. Cerebral perfusion SPECT showed a very low sensitivity (20%) and a good specificity (89%); considering a prevalence of dementia with Lewy bodies of 20%, positive predictive value (PPV) was 31% and negative predictive value (NPV) 82%. Performances of DaTSCAN ® tomoscintigraphy were more encouraging, (sensitivity and specificity of 100%); predictive values are both of 100%. As a conclusion, DaTSCAN ® tomoscintigraphy performs better than cerebral perfusion SPECT in the diagnosis of dementia with Lewy bodies and no conjoint or sequential use of those tests can be recommended.

A Monte Carlo analysis technique applied to cerebral perfusion SPECT scans

Voxel-based techniques are used to provide objective analyses of SPECT scans. The aim of this study was to develop a voxel-based analysis technique that uses a Monte Carlo method of statistical inference and assess this analysis technique for application to cerebral perfusion SPECT scans. Assessment of the validity of this non-parametric, Monte Carlo method of statistical inference has been performed for a range of study designs, image characteristics and analysis parameters using phantom SPECT and Gaussian images. The Monte Carlo method of statistical inference and the voxel-based analysis technique were clinically evaluated for the analysis of individual cerebral perfusion SPECT scans using control subject data. In addition, a comparison has been performed with an existing analysis package that uses a theoretical parametric method of statistical inference (statistical parametric mapping). The Monte Carlo method was found to provide accurate statistical inference for phantom SPECT and Gaussian images independent of degrees of freedom, acquired counts, image smoothness and voxel significance level threshold. The clinical evaluation of the analysis of individual cerebral perfusion SPECT scans demonstrated satisfactory statistical inference and characterization of perfusion deficits. An analysis method incorporating a Monte Carlo method of statistical inference has been successfully applied for the analysis of cerebral perfusion SPECT scans.

SPECT de perfusión cerebral con 99mTc-HMPAO en un caso de encefalitis por VHS

We present a case of encephalitis caused by Herpes Simplex Virus in a 57 year old woman. The acute picture was suggestive of viral infection without associated neurological symptoms. Due to the posterior appearance of neurological focality, cerebral spinal fluid (CSF) was analyzed. It showed pleocytosis and lymphocytosis, inflammatory process data, and serological test with positivity for Simple Herpes Virus (SHV) subtypes I and II. During admission, other complementary tests were performed: EEG, CT, MRI, cerebral perfusion SPECT; the later supplied significant data regarding anatomical neuroimaging (CT, MRI) in regards to bihemispheral extension of the encephalic condition. Furthermore, after clinical discharge, persistent metabolic abnormality was demonstrated in temporal cortex, responsible for concomitant mixed aphasia.

Alzheimer’s disease: differences in technetium-99m HMPAO SPECT scan findings between early onset and late onset dementia

Objective: To compare the HMPAO SPECT cerebral perfusion patterns in early and late onset Alzheimer’s disease. Methods: Twenty patients with early onset disease (<65 years) and 44 patients with late...

Resting and acetazolamide-activated Tc-99m HMPAO brain SPECT for congenital bilateral absence of the internal carotid arteries.

Congenital bilateral absence of the internal carotid arteries (ICAs) is a rare vascular anomaly in humans. Most patients generally have an asymptomatic clinical course and the condition is not recognized because there are good collateral pathways to the bilateral anterior circulation. However, the condition may be discovered as a result of cerebrovascular complications such as hemodynamic transient ischemic attacks, subarachnoid hemorrhage, and ruptured intracranial aneurysms. In patients with this condition, the pathogenesis of cerebrovascular disease may be associated closely with hemodynamic stress caused by hemodynamics. It is therefore important to evaluate regional cerebral blood flow using cerebral perfusion SPECT in patients with congenital bilateral absence of ICAs.

Cerebral perfusion pressure and spect in patients after craniocerebral injury with transtentorial herniation.

We present a group of 29 consecutive head injured comatose patients with the syndrome of transtentorial herniation. All patients had urgent surgery and then continuous monitoring of ICP, CPP, blood pressure and jugular bulb oximetry was instituted. Two postoperative CT and SPECT examinations were performed in each patient. 15 patients had a normal CPP (> 70 mmHg) throughout the postoperative period, 80% of them had a favourable outcome. On the other hand 14 patients had decreased CPP lasting at least one hour and only 36% of them had a favourable outcome (p < 0.05). Similar relationships were found comparing GOS in patients with normal and increased ICP (> 20 mmHg) and normal and decreased SjO2 (< 55%). All but 3 patients had ischaemia on SPECT. Ischaemia improved on the 2nd SPECT in 11 patients and 10 (91%) of them had a favourable outcome. GOS (mean follow up 9 months) is: 12 patients good, 5 moderately disabled, 2 vegetative, 10 died. We conclude that SPECT is able to disclose even reversible ischaemic changes. In these patients all effort has to be made to keep CPP on normal levels. Improvement in cerebral perfusion is related to a better outcome.

Ictal SPECT during autonomic crisis in familial dysautonomia

The authors report results of SPECT cerebral perfusion studies in two patients with familial dysautonomia (FD) during dysautonomic crises and when clinically stable. SPECT imaging studies used 99mTc ethylene cysteine dimer. During dysautonomic crises, regions in the temporoparietal and frontal lobes had increased uptake. Uptake in these areas was less during asymptomatic periods. Episodic asymmetric cerebral perfusion during crises especially affecting the frontal and temporal lobes is suggestive of ictal activity.

Automated recognition of diffuse vs focal nature of abnormal brain perfusion distribution on SPECT cerebral perfusion studies

Automated recognition of diffuse vs focal nature of abnormal brain perfusion distribution on SPECT cerebral perfusion studies

Visual and Quantitative Analysis of Ictal Cerebral Perfusion SPECT in Comparison to High Resolution MRI and EEG in Partial Epilepsy

s Presented At The 22Nd Annual Western Regional Meeting Of The Society Of Nuclear Medicine October 1997