PurposeArtificial neural networks (ANN) might help to diagnose coronary artery disease. This study aimed to determine whether the diagnostic accuracy of an ANN-based diagnostic system and conventional quantitation are comparable.MethodsThe ANN was trained to classify potentially abnormal areas as true or false based on the nuclear cardiology expert interpretation of 1001 gated stress/rest 99mTc-MIBI images at 12 hospitals. The diagnostic accuracy of the ANN was compared with 364 expert interpretations that served as the gold standard of abnormality for the validation study. Conventional summed stress/rest/difference scores (SSS/SRS/SDS) were calculated and compared with receiver operating characteristics (ROC) analysis.ResultsThe ANN generated a better area under the ROC curves (AUC) than SSS (0.92 vs. 0.82, p < 0.0001), indicating better identification of stress defects. The ANN also generated a better AUC than SDS (0.90 vs. 0.75, p < 0.0001) for stress-induced ischemia. The AUC for patients with old myocardial infarction based on rest defects was 0.97 (0.91 for SRS, p = 0.0061), and that for patients with and without a history of revascularization based on stress defects was 0.94 and 0.90 (p = 0.0055 and p < 0.0001 vs. SSS, respectively). The SSS/SRS/SDS steeply increased when ANN values (probability of abnormality) were >0.80.ConclusionThe ANN was diagnostically accurate in various clinical settings, including that of patients with previous myocardial infarction and coronary revascularization. The ANN could help to diagnose coronary artery disease.

Reduction in cardiac ¹²³I-metaiodobenzylguanidine (MIBG) uptake is a characteristic feature of Parkinson’s disease (PD) and dementia with Lewy bodies (DLB), and is useful in distinguishing them from other neurodegenerative disorders. The aim of this study was to investigate the role of this method of scintigraphy in the differential diagnosis of dementia in our Memory Clinic. We performed MIBG scintigraphy in patients with dementia referred to the Memory Clinic and compared the heart-to-mediastinum (H/M) ratio of MIBG uptake. Thirty out of 32 patients with DLB and all 9 PD with dementia patients had reduced H/M ratios, whereas 37 out of 40 patients with Alzheimer’s disease had normal H/M ratios. Most patients with vascular dementia, frontotemporal dementia, and other dementias had normal H/M ratios. The overall sensitivity to positively identify patients with Lewy body disease (including DLB and PD with dementia) was 95%, and the specificity to distinguish them from patients with other types of dementias was 87%. MIBG scintigraphy showed a high sensitivity for the detection of Lewy body disease, and also a high specificity for discrimination from other types of dementia. The scintigraphy may provide a valuable and adjunctive method in the diagnosis of Lewy body disease and a differential diagnostic tool for patients with dementias.

Circulation Journal Official Journal of the Japanese Circulation Society http://www. j-circ.or.jp he development of electrocardiogram-gated single-photon emission computed tomography (SPECT) has enabled the assessment of left ventricular (LV) function after stress and at rest, which has in turn enabled better detection of coronary artery disease (CAD), particularly that of multivessel pathology. 1-4 Recently, a novel technique was developed to evaluate not only myocardial function, but also LV mechanical dyssynchrony using phase analysis on gated SPECT. 5,6 Using this method, several studies have reported the diagnostic and prognostic value of LV mechanical dyssynchrony in patients with heart failure. 7-9 Although LV regional disparities in contractility are known to occur during periods of demand ischemia such as in exercise or dobutamine infusion, 10,11 few studies have analyzed LV mechanical dyssynchrony after stress and at rest to detect high-risk CAD by applying count-based temporal and spatial phase analysis. 12, 13 Considering the diagnostic challenge of multivessel CAD due to balanced ischemia on myocardial SPECT, we retrospectively evaluated whether exercise-induced LV mechanical dyssynchrony as assessed on phase analysis may have enhanced diagnostic value over conventional perfusion analysis in the detection of multivessel CAD. Editorial p 1832Methods Subjects Subjects consisted of 278 consecutive patients (241 men and 37 women; mean age 62±10 years) with suspected or known Background: Although stress-induced left ventricular (LV) wall motion abnormality is a well-known marker for extensive coronary artery disease (CAD), no study has yet analyzed whether phase analysis of exercise-induced LV mechanical dyssynchrony may have enhanced diagnostic value over conventional perfusion analysis in the detection of multivessel CAD.

lthough stress-induced wall motion abnormalities usually disappear rapidly once myocardial ischemia is eliminated, there are a few cases in which wall motion abnormalities remain, even >30 min after elimination of the ischemia; myocardial stunning is the apparent mechanism in such cases. [1][2][3][4][5][6] The characteristics of technetium-99m ( 99m Tc)-sestamibi, which rarely redistributes, 7 in conjunction with electrocardiogram-gated single-photon emission computed tomography (SPECT) enables assessment of both myocardial ischemia during stress and left ventricular wall motion and function at least 30 min after the stress. 8,9 Although myocardial stunning has been mainly shown after exercise-induced ischemia, 1-6 pharmacologic vasodilation, which induces maldistribution of the blood flow in the intramyocardium, is commonly used as the method of inducing stress during myocardial perfusion imaging. Therefore, the aims of the present study were to evaluate the myocardial stunning induced by standard stress tests in clinical practice, and to compare the development of myocardial stunning with either exercise or pharmacologic stress. Methods SubjectsThe subjects were 179 consecutive patients with known or suspected coronary artery disease (CAD), who underwent exercise or adenosine triphosphate disodium (ATP) stress myocardial perfusion imaging. Patients with a history of coronary angioplasty or bypass graft surgery were considered to have known CAD, whereas those with a clinical risk profile, symptoms or electrocardiographic abnormalities were considered as having suspected CAD. Patients with a history of prior myocardial infarction were excluded. In total, there were 112 men and 67 women, with a mean age of 66±9 years, and 77 of them underwent coronary angiography because of clinical symptoms, electrocardiographic abnormalities or scintigraphic findings. Of those with known CAD, 50 patients had a history of coronary revascularization (coronary angioplasty in 39 patients, coronary artery bypass grafting in 11). Written informed consents were given by all participants. Stress 99m Tc-Sestamibi SPECTStress myocardial SPECT with 99m Tc-sestamibi was performed using a 1-day exercise -rest protocol. 10 Exercise Background Exercise gated single-photon emission computed tomography (SPECT) using technetium-99m ( 99m Tc)-sestamibi evaluates both myocardial perfusion during stress and wall motion >30 min after the stress, which has the potential to assess not only exercise-induced myocardial ischemia but also the development of myocardial stunning. Methods and ResultsTo evaluate the incidence of post-stress myocardial stunning, as well as comparing the effects of different stress methods on the development of stunning, 179 consecutive patients with known or suspected coronary artery disease (CAD) underwent 99m Tc-sestamibi SPECT with either exercise (n=135) or adenosine triphosphate disodium (ATP) (n=44). Electrocardiogram-gated SPECT images were acquired >30 min after the stress and again 4 h later, and perfusion and wall mo...

The addition of "post-ATP stress" and "at rest" LV functional analysis using gated SPECT to conventional perfusion analysis helps to better identify patients with multi-vessel CAD.

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The addition of poststress and at-rest LV functional analysis by use of gated SPECT to conventional perfusion analysis helps to better identify patients with multivessel CAD.

Background: Although the Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) score is used to characterize coronary anatomy based on 9 anatomic criteria such as lesion location and complexity, the relationship between SYNTAX score and myocardial ischemia has yet to be elucidated. Methods and Results:A total of 158 consecutive patients with suspected or known coronary artery disease (CAD), who underwent both 99 m Tc-sestamibi single-photon emission computed tomography (SPECT) and coronary angiography, were evaluated. Stress SPECT was assessed using a 17-segment model, and the percentage of the myocardial defect scores (DS) was calculated. In 37 patients with intermediate-high SYNTAX scores (>22), the number of men and the prevalence of multi-vessel CAD were significantly higher, and the % stress and ischemic DS were significantly greater than in 121 patients with low SYNTAX scores (≤22). Coronary risk factors, however, were similar between the 2 groups. The % stress and ischemic DS significantly correlated with SYNTAX score. In patients with a low SYNTAX score, % stress and ischemic DS also significantly correlated with the SYNTAX score, whereas no such correlation was observed in the intermediate-high SYNTAX score group.Conclusions: SYNTAX score correlated well with myocardial ischemia as assessed on stress SPECT in general. The higher the SYNTAX score, however, the less clear was the correlation with the extent of myocardial ischemia. (Circ J 2013; 77: 2772 -2777