Analysis Of Single Photon Emission Research Articles

Three-dimensional stereotactic surface projection in the statistical analysis of single photon emission computed tomography data for distinguishing between Alzheimer's disease and depression.

AIMTo evaluate usefulness of single photon emission computed tomography (SPECT) with three-dimensional stereotactic surface projection (3D-SSP) in distinguishing between Alzheimer’s disease (AD) and depression.METHODSWe studied 43 patients who presented with both depressive symptoms and memory disturbance. Each subject was evaluated using the following: (1) the Minimal Mental State Examination; (2) the Hamilton Rating Scale for Depression; (3) Clinical Global Impression-Severity scale (CGI-S); and (4) SPECT imaging with 3D-SSP.RESULTSThe MMSE scores correlated significantly with the maximum Z-scores of AD-associated regions. CGI-S scores correlated significantly with the maximum Z-scores of depression-associated regions. Factor analysis identified three significant factors. Of these, Factor 1 could be interpreted as favouring a tendency for AD, Factor 2 as favouring a tendency for pseudo-dementia, and Factor 3 as favouring a depressive tendency.CONCLUSIONWe investigated whether these patients could be categorized as types: Type A (true AD), Type B (pseudo-dementia), Type C (occult AD), and Type D (true depression). The factor scores in factor analysis supported the validity of this classification. Our results suggest that SPECT with 3D-SSP is highly useful for distinguishing between depression and depressed mood in the early stage of AD.

Development and optimization of SPECT gated blood pool cluster analysis for the prediction of CRT outcome

Phase analysis of single photon emission computed tomography (SPECT) radionuclide angiography (RNA) has been investigated for its potential to predict the outcome of cardiac resynchronization therapy (CRT). However, phase analysis may be limited in its potential at predicting CRT outcome as valuable information may be lost by assuming that time-activity curves (TAC) follow a simple sinusoidal shape. A new method, cluster analysis, is proposed which directly evaluates the TACs and may lead to a better understanding of dyssynchrony patterns and CRT outcome. Cluster analysis algorithms were developed and optimized to maximize their ability to predict CRT response. About 49 patients (N = 27 ischemic etiology) received a SPECT RNA scan as well as positron emission tomography (PET) perfusion and viability scans prior to undergoing CRT. A semiautomated algorithm sampled the left ventricle wall to produce 568 TACs from SPECT RNA data. The TACs were then subjected to two different cluster analysis techniques, K-means, and normal average, where several input metrics were also varied to determine the optimal settings for the prediction of CRT outcome. Each TAC was assigned to a cluster group based on the comparison criteria and global and segmental cluster size and scores were used as measures of dyssynchrony and used to predict response to CRT. A repeated random twofold cross-validation technique was used to train and validate the cluster algorithm. Receiver operating characteristic (ROC) analysis was used to calculate the area under the curve (AUC) and compare results to those obtained for SPECT RNA phase analysis and PET scar size analysis methods. Using the normal average cluster analysis approach, the septal wall produced statistically significant results for predicting CRT results in the ischemic population (ROC AUC = 0.73;p < 0.05 vs. equal chance ROC AUC = 0.50) with an optimal operating point of 71% sensitivity and 60% specificity. Cluster analysis results were similar to SPECT RNA phase analysis (ROC AUC = 0.78, p = 0.73 vs cluster AUC; sensitivity/specificity = 59%/89%) and PET scar size analysis (ROC AUC = 0.73, p = 1.0 vs cluster AUC; sensitivity/specificity = 76%/67%). A SPECT RNA cluster analysis algorithm was developed for the prediction of CRT outcome. Cluster analysis results produced results equivalent to those obtained from Fourier and scar analysis.

Comment on Grippaudo et al.: Radiolabelled white blood cell scintigraphy in the work-up of dermal filler complications

Dear Sir, I read with great interest the recent article by Grippaudo et al. [1]. The authors evaluated the role of WBC scintigraphy in the diagnosis and follow-up of patients with suspected soft tissue infection caused by dermal fillers in the face. They concluded that scintigraphy with radiolabelled WBC was found to be the most accurate method for diagnosing infection in patients with long-term dermal filler complications, particularly using qualitative analysis of single photon emission computed tomography (SPECT) images. I think infection should be classified as an acute or subacute complication related to dermal fillers. Rather, foreign body granuloma is a delayed or long-term dermal filler complication [2, 3]. Therefore, it is reasonable to say that infection can be accompanied by a granulomatous reaction. Although accurate diagnosis has been made using scintigraphy with radiolabelled WBC, this novel method cannot affect the treatment modality. Clinically, once physicians suspect filler-related infection, they should commence adequate culture followed by appropriate antibiotic therapy [4, 5]. In my opinion, it would be more practical if clinicians could exclude soft tissue tumour in the cases of foreign body granuloma by use of scintigraphy with radiolabelled WBC. Diagnosis of dermal filler-related infection with such a novel method is less cost-effective. In addition, depending on such a novel method for follow-up of patients with suspected soft tissue infection caused by dermal fillers cannot be justified in all cases. I think scintigraphy with radiolabelled WBC only reveals inflammatory reactions without providing additional information about the injected materials or otherwise while incurring additional costs to the patients. Due to its cost-effectiveness, surgeons have ceased to conduct a routine diagnostic imaging study once clinical diagnoses are confirmed. In my opinion, clinical challenges originate not from an insufficient diagnostic method but mainly from the difficulty in obtaining an accurate history. Above all, accurate diagnosis based on clinical suspicion is the most important to define treatment [4]. However, as dermal filler injections have become widespread and subsequent infection/inflammation or granuloma have increased, I agree with Grippaudo et al. that physicians treating these complicated conditions should be familiar with the novel diagnostic method [1]. With various dermal fillers, attempts to rejuvenate the aging hands also have recently gained popularity [5]. I suggest that further study with complications of hand rejuvenation can also be of great interest to many clinicians with the novel method introduced by the authors. To the best of our knowledge, the article by Grippaudo et al. is the first study to introduce scintigraphy with radiolabelled WBC for the diagnosis and follow-up of injected filler complications. This issue itself has special merit to many surgeons as well as other physicians treating this complicated condition and further studies with granulomatous lesions caused by dermal filler are warranted.

Deep gray matter hyperperfusion with occipital hypoperfusion in dementia with Lewy bodies

Although decreased occipital perfusion is a characteristic feature of dementia with Lewy bodies (DLB), not all patients with DLB show a significant decreased perfusion in the occipital lobe. We explored characteristics of perfusion changes to improve the identification of DLB, in addition to occipital hypoperfusion. Statistical image analysis of single photon emission computed tomography data was performed on 22 patients with DLB and 25 patients with Alzheimer's disease (AD). A significant decreased perfusion in the occipital lobe was found in 16 patients with DLB (72%) and three patients with AD (12%), while a significant increased perfusion in the deep gray matter (striatum and/or thalamus) was found in 18 patients with DLB (81%) and eight patients with AD (31%), respectively. Either occipital hypoperfusion or deep gray matter hyperperfusion was found in 21 patients with DLB (95%), while in nine patients with AD (35%), indicating a sensitivity of 95% and a specificity of 65% in discriminating DLB from AD. Our results suggest that the addition of deep gray matter hyperperfusion to occipital hypoperfusion may be useful in the clinical differentiation of DLB and AD.

Objective Analysis of Tomographic Ventilation–Perfusion Scintigraphy in Pulmonary Embolism

Ventilation-perfusion scintigraphy is highly sensitive for pulmonary embolism (PE), but its clinical usefulness is limited by its nondiagnostic rate. Objective analysis of single photon emission computed tomography (SPECT) three-dimensional scintigraphy may improve its diagnostic performance compared with subjective interpretation. To determine the diagnostic accuracy of objective SPECT analysis in PE. We determined the ventilation/perfusion (V(.)/Q(.)) relationship using SPECT scintigraphy in a retrospective cohort of 73 patients. Measures of V(.)/Q(.) heterogeneity (logSD(Q(.)), logSD(V(.)), logSD(VQR)), including a novel parameter, the weighted median V(.)/Q(.) value, were calculated. Using receiver operating characteristic (ROC) analysis, each parameter's diagnostic accuracy was determined. The weighted median V(.)/Q(.) value was then assessed prospectively in a second cohort of 50 patients. In cohort 1, all parameters of V(.)/Q(.) heterogeneity were higher in patients with PE (p < 0.002). The weighted median V(.)/Q(.) had the highest area under the ROC curve (0.93; 95% confidence interval, 0.87-0.98). When applied to the prospective cohort, the area under the ROC curve was 0.87 (95% confidence interval, 0.75-0.99), with diagnostic cutoff values having negative and positive predictive values of 96 and 83%, respectively. In the retrospective and prospective cohorts, 82 and 73% of initially reported intermediate or low probability scans had diagnostic weighted median V(.)/Q(.) values, with 90 and 100% accuracy, respectively. Objective analysis of SPECT scintigraphy has a high diagnostic accuracy in patients with suspected PE. Objective analysis has the potential to reduce the number of nondiagnostic scan results, and may be useful for quantifying V(.)/Q(.) mismatch in other pulmonary disorders.

Prediction of psychiatric response to donepezil in patients with mild to moderate Alzheimer's disease

Donepezil is a selective acetylcholinesterase inhibitor approved for the symptomatic treatment of mild to moderate Alzheimer's disease (AD). Since behavioral symptoms severely affect quality of life for AD patients and their caregivers, predicting behavioral responses to donepezil will be useful in managing patients with AD. In this study, we analyzed 70 consecutive cases with mild to moderate AD. Caregivers were interviewed with the Neuropsychiatric Inventory for behavioral assessment and 4-point improvement at week 12 was accepted as a treatment response. Twenty-one (30.0%) patients showed a behavioral response, while 42 (60.0%) showed no behavioral change and 7 (10.0%) worsened. Dysphoria, anxiety and apathy significantly improved after treatment among the responder group. The baseline profile including age, sex, Mini-Mental State Examination (MMSE), the Alzheimer's Disease Assessment Scale (ADAS-cog) and the Geriatric Depression Scale did not differ significantly among the three groups. Statistical Parametric Mapping analysis of single photon emission computed tomography (SPECT) images at baseline showed that cerebral blood flow in the premotor and parietotemporal cortices was significantly higher in the responder group than in the worse group. The present study suggested usefulness of SPECT imaging in the prediction of behavioral response to donepezil among AD patients even with similar psychiatric symptoms and cognitive functions.

Hypoperfusion of inferior frontal brain regions in abstinent alcoholics: a pilot SPECT study.

This pilot study evaluated hypotheses concerning the relationship between cerebral hypoperfusion and residual deficits in the functioning of frontal brain systems in abstinent long-term alcoholics. The participants (N = 22) were 10 healthy, abstinent alcoholics (9 men) and 12 age-equivalent nonalcoholic controls (10 men). Cerebral blood flow was observed through the use of regionally specific computer-derived quantitative analysis of single photon emission computed tomography (SPECT) perfusion images. Measures of alcohol use, abstinence and neuropsychological functioning were also obtained to relate to SPECT findings. A positive relationship was observed between perfusion levels in the left inferior frontal brain region and years of sobriety. Alcoholics with less than 4 years of sobriety had significantly reduced left inferior frontal perfusion compared with both nonalcoholic controls and alcoholics having longer periods of sobriety. The findings support the hypothesis that frontal brain abnormalities in alcoholics may subside with extended abstinence.

Hypoperfusion of the Cerebellum and Aging Effects on Cerebral Cortex Blood Flow in Abstinent Alcoholics: A SPECT Study

This study evaluated hypotheses concerning alcoholism, aging, and the relationship between cerebral hypoperfusion and residual deficits in the functioning of cerebellar and neocortical brain systems. The participants were 10 healthy abstinent alcoholics (9 men, 1 woman) and 12 nonalcoholic controls (10 men, 2 women) ranging in age from 35 to 67 years. Cerebral blood flow was observed through the use of regionally specific computer-derived quantitative analysis of single photon emission computed tomography (SPECT) perfusion images. Cerebellar perfusion was measured and compared with cerebral cortex perfusion in age-equivalent subgroups of alcoholics and controls (under 55 years; 55 years and over). In abstinent alcoholics under age 55, cerebellar perfusion ratios were significantly reduced compared with the controls. In alcoholics and nonalcoholic controls 55 years old and older, this relationship was reversed, probably as a result of diminished cortical perfusion with aging in the alcoholics and of cerebellar decline in the controls. The findings support hypotheses that the residual effects of alcoholism include cerebellar brain abnormalities and that aging combined with long-term alcoholism leads to cerebral cortical decline.

SPECT画像のROC解析 : ローパスフィルタの遮断周波数による信号検出能への影響

SPECT画像のROC解析 : ローパスフィルタの遮断周波数による信号検出能への影響

Diagnosis of myocardial contusion. Quantitative analysis of single photon emission computed tomographic scans.

Prior studies from our institution have shown that single photon emission computed tomography is sensitive (100%) in predicting patients at risk for serious arrhythmias. However, the positive predictive value is low (15% to 20%). The purpose of this study was to determine if quantitative analysis of single photon emission computed tomographic defects could improve predictive value. One hundred seventy-five patients with positive single photon emission computed tomographic scans were studied. One hundred two patients developed arrhythmias, 42 of which were ventricular. Arrhythmias were associated with all defect loci and all defect sizes. The incidence of arrhythmias did increase with increasing size. Patients were at risk for arrhythmias up to 72 hours after trauma. The value of single photon emission computed tomography is its ability to predict patients at risk for arrhythmias. This study shows that any single photon emission computed tomographic defect, regardless of location or size, is a significant predictor of arrhythmias.

Information analysis of single photon emission computed tomography with count losses

An analysis is presented of the information transfer from emitter-space to detector-space in single photon emission computed tomography (SPECT) systems. The analysis takes into account the fact that count loss side information is generally not available at the detector. Side information corresponds to the number gamma-rays lost deleted due to lack of interaction with the detector data. It is shown that the information transfer depends on the structure of the likelihood function of the emitter locations associated with the detector data. This likelihood function is the average of a set of ideal-detection likelihood functions, each matched to a particular set of possible deleted gamma-ray paths. A lower bound is derived for the information gain due to incorporating the count loss side information at the detector. This is shown to be significant when the mean emission rate is small or when the gamma-ray deletion probability is strongly dependent on emitter location. Numerical evaluations of the mutual information, with and without side information, associated with information-optimal apertures and uniform parallel-hole collimators are presented.