Stress-rest Myocardial Perfusion Imaging Research Articles

Stress-only versus rest-stress SPECT MPI in the detection and diagnosis of myocardial ischemia and infarction by machine learning.

Rest-stress SPECT myocardial perfusion imaging (MPI) is widely used to evaluate coronary artery disease (CAD). We aim to evaluate stress-only versus rest-stress MPI in diagnosing CAD by machine learning (ML). A total of 276 patients with suspected CAD were randomly divided into training (184 patients) and validation (92 patients) cohorts. Variables extracted from clinical, physiological, and rest-stress SPECT MPI were screened. Stress-only and rest-stress MPI using ML were established and compared using the training cohort. Then the diagnostic performance of two models in diagnosing myocardial ischemia and infarction was evaluated in the validation cohort. Six ML models based on stress-only MPI selected summed stress score, summed wall thickness score of stress%, and end-diastolic volume of stress as key variables and performed equally good as rest-stress MPI in detecting CAD [area under the curve (AUC): 0.863 versus 0.877, P = 0.519]. Furthermore, stress-only MPI showed a reasonable prediction of reversible deficit, as shown by rest-stress MPI (AUC: 0.861). Subsequently, nomogram models using the above-stated stress-only MPI variables showed a good prediction of CAD and reversible perfusion deficit in training and validation cohorts. Stress-only MPI demonstrated similar diagnostic performance compared with rest-stress MPI using 6 ML algorithms. Stress-only MPI with ML models can diagnose CAD and predict ischemia from scar.

Machine learning-based diagnosis and risk classification of coronary artery disease using myocardial perfusion imaging SPECT: A radiomics study

This study aimed to investigate the diagnostic performance of machine learning-based radiomics analysis to diagnose coronary artery disease status and risk from rest/stress Myocardial Perfusion Imaging (MPI) single-photon emission computed tomography (SPECT). A total of 395 patients suspicious of coronary artery disease who underwent 2-day stress-rest protocol MPI SPECT were enrolled in this study. The left ventricle myocardium, excluding the cardiac cavity, was manually delineated on rest and stress images to define a volume of interest. Added to clinical features (age, sex, family history, diabetes status, smoking, and ejection fraction), a total of 118 radiomics features, were extracted from rest and stress MPI SPECT images to establish different feature sets, including Rest-, Stress-, Delta-, and Combined-radiomics (all together) feature sets. The data were randomly divided into 80% and 20% subsets for training and testing, respectively. The performance of classifiers built from combinations of three feature selections, and nine machine learning algorithms was evaluated for two different diagnostic tasks, including 1) normal/abnormal (no CAD vs. CAD) classification, and 2) low-risk/high-risk CAD classification. Different metrics, including the area under the ROC curve (AUC), accuracy (ACC), sensitivity (SEN), and specificity (SPE), were reported for models’ evaluation. Overall, models built on the Stress feature set (compared to other feature sets), and models to diagnose the second task (compared to task 1 models) revealed better performance. The Stress-mRMR-KNN (feature set-feature selection-classifier) reached the highest performance for task 1 with AUC, ACC, SEN, and SPE equal to 0.61, 0.63, 0.64, and 0.6, respectively. The Stress-Boruta-GB model achieved the highest performance for task 2 with AUC, ACC, SEN, and SPE of 0.79, 0.76, 0.75, and 0.76, respectively. Diabetes status from the clinical feature family, and dependence count non-uniformity normalized, from the NGLDM family, which is representative of non-uniformity in the region of interest were the most frequently selected features from stress feature set for CAD risk classification. This study revealed promising results for CAD risk classification using machine learning models built on MPI SPECT radiomics. The proposed models are helpful to alleviate the labor-intensive MPI SPECT interpretation process regarding CAD status and can potentially expedite the diagnostic process.

P150 STRESS–REST DYNAMIC–CT MYOCARDIAL PERFUSION IMAGING IN THE MANAGEMENT OF MYOCARDIAL BRIDGING: A “ONE–STOP SHOP” EXAM

Abstract Myocardial bridging (MB) is a congenital anomaly characterized by intramyocardial coronary course that can cause coronary compression during systole and can lead to myocardial ischemia. The improvement in computed tomography (CT) scanner technology has increased the detection of MB during coronary–CT (cCT) exam but the assessment of their functional significance is often challenging. Tha stress–rest myocardial perfusion imaging (MPI) single–photon emission CT (SPECT) is often required to decide patient’s management after anatomical evaluation with cCT or Invasine Coronary Angiography (ICA). However, SPECT has long acquisition protocols, poor spatial resolution, and the anatomical/Functional protocols expose patients to significant radiation doses. Thus, dynamic–CT MPI after cCGT can represent a valid alternative. We report the cases of seven patients in which we detected MBs during cCT exam and we evaluated their functional significance using a stress–rest dynamic–CT MPI to decide the correct patient’s management. Three patients showed reversible perfusion defect in the left anterior descending (LAD) territory segments involved with MB and they were referred for treatment. The remnants four patients with MB in the LAD revealed normal MPI and they were conservatively managed. In all patients the results of the stress perfusion were completely overlapping, but the study with SPECT after anatomical evaluation required a longer process. The cCT and stress–rest dynamic–CT MPI allowed to detect and to evaluate the functional significance and to decide the management of MB in a “one–stop shop” exam.

Initial experience regarding the safety and yield of rest-stress myocardial perfusion imaging in emergency department patients with mildly abnormal high-sensitivity cardiac troponins

BackgroundWith high-sensitivity troponin testing, approximately a third of patients presenting to emergency departments (EDs) with suspected acute coronary syndromes will have mildly abnormal values. However, data regarding rest-stress myocardial perfusion imaging (MPI) in these patients are limited. We hypothesize that stress testing is safe and that the yield for detecting myocardial ischemia is associated with risk stratification by the HEART score. Methods and ResultsWe conducted a retrospective cohort study of consecutive patients referred for rest-stress MPI with mildly abnormal high-sensitivity troponin T (hs-cTn) values. Outcomes were adverse events related to stress MPI, defined as myocardial infarction or ventricular tachyarrhythmia, and the presence of ischemia, defined as a reversible perfusion defect. Among 213 patients, the median age was 67, most were male (61.5%, n = 131), and prior CAD was common (53.5%, n = 114). Myocardial ischemia was present in 13.6% (n = 29), and there were no adverse events attributable to stress MPI. A higher HEART score was associated with myocardial ischemia (Odds Ratio [OR] 1.50, 95% Confidence Interval [CI] 1.08 to 2.08, P = .002). ConclusionRest-stress MPI appears safe in patients with mildly abnormal hs-cTn values, and the yield for detecting ischemia is associated with the HEART score, though further validation studies are needed.

The Role of Myocardial Perfusion Imaging in Patients with Diabetes Mellitus

Abstract Diabetes mellitus is a complex pathology with increasing incidence, associated with an increased risk of coronary heart disease. Myocardial perfusion imaging (MPI) is an important diagnostic tool for the evaluation of coronary artery disease (CAD), with a high prognostic value. Objective. The aim of this study was to evaluate the role of stress-rest MPI in the assessment of patients with DM and suspected or confirmed CAD. Method. We performed a retrospective analysis of 128 patients who underwent stress-rest MPI in our department, all of them with coronary angiography (CA) available. All patients underwent stress rest myocardial perfusion SPECT using a 1-day or 2-day protocol. The radiopharmaceuticals used were 99m-Tc-MIBI or tetrofosmin. The study was performed with a gated protocol SPECT, synchronous with the ECG, using a dual-head gamma camera. Patients were divided in 4 subgroups based on the presence of DM and of significant CA changes. Results. In the group of patients with significant coronary disease on CA and previously diagnosed DM, number of perfusion defects on the stress-rest MPI were higher and also the presence of systolic disfunction and the severity of defects. Our results support the idea that the severity and extent of myocardial perfusion defects are greater in diabetic patients than in non-diabetic patients. Conclusions. We can consider myocardial perfusion SPECT with 99mTc-labeled agents as a feasible method for the diagnosis and evaluation of CAD and for the management of diabetic patients.

Cardiac Sarcoidosis Mimicking Anterior Myocardial Infarction.

A 58-year-old asymptomatic man with electrocardiogram (ECG) abnormality was referred to our institution for cardiac exams. His ECG showed a bifascicular block, and the echocardiography demonstrated a wall motion abnormality in apex. Stress-rest myocardial perfusion imaging (MPI) showed a significant defect in anterior wall with partial redistribution at rest. He was suspected of having an anterior myocardial infarction (MI) and underwent cardiac catheterization. However, coronary angiography (CAG) revealed no significant coronary atherosclerosis. Cardiovascular magnetic resonance imaging (CMR) was performed to evaluate the extent of myocardial infarction. Late gadolinium enhancement (LGE) demonstrated a significant epicardial and midmyocardial LGE in the multiple site including anterior, anteroseptal, lateral, inferior wall, and basal right ventricle junction, which strongly indicated that the fibrosis was due to cardiac sarcoidosis (CS).A myocardial perfusion defect in anterior wall shown in the MPI revealed the fibrosis as an atypical finding mimicking anterior MI.

Changes in left ventricle myocardial volume during stress test using cadmium-zinc-telluride cardiac imaging: Implications in coronary artery disease

BackgroundCadmium-zinc-telluride (CZT) SPECT allows the estimation of left ventricle myocardial volume (LVMV). We tested the clinical relevance of rest-stress LVMV changes (Δ LVMV) in detecting coronary artery disease (CAD, coronary stenosis > 70%), using CZT-SPECT. MethodsWe prospectively enrolled 512 consecutive patients with known or suspected CAD (mean age: 70.3 ± 9.2 years, 72% male) for stress-rest myocardial perfusion imaging (MPI, single-day stress-rest protocol). We quantified summed stress scores (SSS), summed rest scores, and summed difference scores, together with LVMV and ejection fraction (EF) after stress and at rest. All patients underwent coronary angiography within 30 days. ResultsTwo hundred seventy-two patients had CAD at coronary angiography. ΔLVMV ≤ 5 mL, corresponding to 6% of change from rest LVMV, was the best predictor of CAD (AUC = 0.831, 79% sensitivity, 82% specificity), irrespective of the stress protocol (dipyridamole or exercise stress) and independently of MPI-SSS, LV EF, and clinical history (P = 0.004). Integrated discrimination improvement (IDI) and net reclassification improvement (NRI) were significant for the addition of ΔLVMV ≤ 5 mL (IDI = 6.1%, P < 0.0001; NRI = 29.7%, P = 0.02) to MPI-SSS, whereas the other parameters were not. ConclusionsThe evaluation of ΔLVMV using CZT-SPECT can improve the diagnostic accuracy in predicting the presence of CAD when added to conventional MPI.

Stress only myocardial perfusion imaging - comparison of hospitalized and outpatient patients

Abstract Funding Acknowledgements Type of funding sources: None. Background In selected patients, stress-only myocardial perfusion imaging (MPI) has been proposed as an alternative to rest-stress MPI to reduce radiation exposure and enhance laboratory efficiency. The use of attenuation correction improves the diagnostic accuracy of stress-only imaging. However, criteria for selecting appropriate patients for stress-first imaging protocol are not uniform. There is limited data about stress-only MPI in hospitalized patients. The purpose of this study was to compare the proportion of suitable hospitalized and outpatient patients with normal MPI on a routine two-day protocol for stress-only MPI. Methods In a retrospective longitudinal cohort study, stress scintigrams (with and without attenuation correction) of consecutive hospitalized and outpatient patients who underwent MPI at our department by a routine two-day protocol and had a normal MPI were visually and semi-quantitatively re-examined. Patients with summed stress score 0 or 1 were considered as candidates for stress-only MPI. We also obtained data on the patients" clinical characteristics and their treatment. Results We studied 178 patients (mean age 68.8 ± 13.4 years, 89 hospitalized, 89 outpatient patients, 55.6 % female). Hospitalized patients were significantly older than outpatient participants (72.4 ± 13.0 vs. 65 ± 12.9 years, p &amp;lt; 0.001) with no significant differences in risk factors and clinical characteristics. Proportion of inpatients and outpatients suitable for stress-only MPI with and without attenuation correction is shown on Figure 1. There was no significant difference in stress-only MPI with and without attenuation correction between hospitalized and outpatient patients (Figure 1). 9.1% of patients in whom stress only MPI was possible had known coronary artery disease, whereas it was present in 25.0% of patients in whom stress-only MPI was not possible (p = 0.004). By using attenuation correction stress-only MPI could be performed in 54% of patients without known coronary artery disease. There was no difference between hospitalized patients and outpatients (52% vs. 56%, p = 0.700). Absence of coronary artery disease turned out as the only independent prognostic factor for application of stress-only MPI (odds ratio 3.433, 95% confidence interval 1.44-8.17, p = 0.003). There was no influence of hospitalization on the application of stress-only MPI. Conclusions When we choose the right patients (especially those without a known coronary artery disease) and use modern cameras that enable attenuation correction, we can perform stress-only MPI in 50% of patients with a normal MPI result. The same approach can be used for outpatients and inpatients.

The effect of body mass index on high versus low administered activity protocol myocardial perfusion imaging scan time and effective dose using a cadmium zinc telluride camera in clinical practice.

Cadmium Zinc Telluride (CZT) crystal-based myocardial perfusion imaging (MPI) cameras have increased count sensitivity compared to Anger cameras and can be used to lower either the injected activity or the image acquisition time. Institutions adopting CZT cameras need to decide whether to lower the injected activity or imaging time or attempt to lower both with a compromise. The aim of our study was to compare the scan time required to obtain similar count images using high activity protocol (HAP) versus low activity protocol (LAP) stratified by body mass index (BMI) and assess the impact on effective dose and our clinic workflow. Using a CZT camera, a cohort of 100 consecutive clinical patients imaged with LAP rest-stress MPI with approximately 185 MBq and 555 MBq activity was retrospectively compared to a similar cohort of 100 consecutive clinical patients imaged with HAP rest-stress MPI using approximately 370 MBq and 1110 MBq. Administered activity and BMI both had a statistically significant effect on scan time and radiation effective dose. LAP scans took an average of 9 min longer than HAP scans overall, P < 0.0001 and larger BMIs took longer than smaller BMIs, P < 0.0001. In addition, scan times were longer in men than women, P = 0.007. Effective dose was inversely proportional to BMI with an overall decrease of approximately 50% comparing LAP to HAP. For the same CZT camera, the LAP increased scan time while lowering the radiation effective dose when compared to HAP. The increase in scan time increased proportionally to BMI. The effective dose was inversely proportional to BMI. This increase in time did not have a significant impact on our local workflow, but its implications should be considered in the setting of LAP implementation, especially in obese or high patient volume practices.

Prognostic value of myocardial perfusion scintigraphy in diabetic patients and without coronary lesion

ObjectiveTo determine the prognostic value of myocardial perfusion scintigraphy-gated SPECT in patients with diabetes mellitus and without obstructive coronary artery disease. Materials and methodsThis retrospective study included consecutive patients undergoing adenosine stress-rest myocardial perfusion imaging (MPI) by 99mTc-tetrofosmin between 2009 and 2011. The patients had diabetes mellitus and coronary angiography without significant coronary lesions. In total, 37 diabetic patients (female/male: 20/17; mean age: 65.2 (range: 40−78). 29 non-diabetic patients were included wich are matched with the group of diabetic patients with positive MPI. The group of non-diabetic patients had scintigraphy with myocardial ischemia and without angiographic lesions. A 36-month clinical follow-up was performed, and major cardiac events were recorded. ResultsIn 78.3% (29/37) of diabetic patients the scintigraphic study showed myocardial ischemia, while it was negative in the 21.7%. The cardiac event rate in both groups was 6%. In diabetics with a myocardial perfusion study with myocardial ischemia, there were 3 major cardiac events. In diabetic patients with negative study had no cardiac event. In the non-diabetic control group the cardiac events rate was 3.4% (1/29). ConclusionIn diabetic patients without obstructive coronary disease, myocardial perfusion study can be predictor of cardiac events. A negative study can be an indicator of a better cardiovascular prognosis.

Prognostic value of coronary vascular dysfunction assessed by rubidium-82 PET/CT imaging in patients with resistant hypertension without overt coronary artery disease

PurposeThe identification of coronary vascular dysfunction may enhance risk stratification in patients with resistant hypertension (RH). We evaluated if impaired coronary vascular function, assessed by rubidium-82 (82Rb) positron emission tomography/computed tomography (PET/CT) imaging, is associated with increased cardiovascular risk in patients with hypertension without overt coronary artery disease (CAD).MethodsWe studied 517 hypertensive subjects, 26% with RH, without overt CAD, and with normal stress-rest myocardial perfusion imaging at 82Rb PET/CT. The outcome end points were cardiac death, nonfatal myocardial infarction, coronary revascularization, and admission for heart failure.ResultsOver a median of 38 months (interquartile range 26 to 50), 21 cardiac events (4.1% cumulative event rate) occurred. Patients with RH were older (p < 0.05) and had a higher prevalence of left ventricular hypertrophy (p < 0.001), a lower hyperemic myocardial blood flow (MBF), and myocardial perfusion reserve (MPR) (both p < 0.001) compared to those without. Conversely, coronary artery calcium content and baseline MBF were not different between patients with and without RH. At univariable Cox regression analysis, age, RH, left ventricular ejection fraction, coronary artery calcium score, and reduced MPR were significant predictors of events. At multivariable analysis, age, RH, and reduced MPR (all p < 0.05) were independent predictors of events. Patients with RH and reduced MPR had the highest risk of events and the major risk acceleration over time.ConclusionThe findings suggest that the assessment of coronary vascular function may enhance risk stratification in patients with hypertension.

Optimal 99mTc activity ratio in the single-day stress-rest myocardial perfusion imaging protocol: A multi-SPECT phantom study

BackgroundThis investigation used image data generated by an anthropomorphic phantom to determine the minimal 99mTc rest-stress activity concentration ratio (R) able to minimize the ghosting effect in the single-day stress-first myocardial perfusion imaging, using different positions of the perfusion defect (PD), scanners and reconstruction protocols. MethodsA cardiac phantom with a simulated PD was imaged under different R using different gamma cameras and reconstruction algorithms. The residual activity from precedent stress administration was simulated by modeling effective half-times in each compartment of the phantom and assuming a delay of 3 hours between the stress and rest studies. The net contrast (NC) of the PD in the rest study was assessed for different R, PD positions and scanner/software combinations. The optimal R will be the one that minimize the NC in the rest images ResultsThe activity concentration ratio R, the position of the PD and the scanner/software combinations were all main effects with a statistically significant impact on the NC, in decreasing order of relevance. The NC diminished significantly only for R values up to 2. No further improvement was observed for NC for R values above 2 and up to 3. NC was significantly higher in anteroseptal than in posterolateral positions of the PD and higher for solid-state cameras. ConclusionsA rest-stress activity concentration ratio R of 2 in single-day stress-first myocardial perfusion imaging is enough to achieve the maximum net contrast in the PD. This ratio should be used to optimize patient’s radiation exposure.

Valor pronóstico de la gammagrafía de perfusión miocárdica en pacientes diabéticos sin lesiones coronarias

ObjectiveTo determine the prognostic value of myocardial perfusion scintigraphy-gated SPECT in patients with diabetes mellitus and without obstructive coronary artery disease. Materials and methodsThis retrospective study included consecutive patients undergoing adenosine stress-rest myocardial perfusion imaging (MPI) by 99mTc-tetrofosmin between 2009 and 2011. The patients had diabetes mellitus and coronary angiography without significant coronary lesions. In total, 37 diabetic patients (female/male: 20/17; mean age: 65.2 (range: 40-78). 29 non-diabetic patients were included wich are matched with the group of diabetic patients with positive MPI. The group of non-diabetic patients had scintigraphy with myocardial ischemia and without angiographic lesions. A 36-month clinical follow-up was performed, and major cardiac events were recorded. ResultsIn 78.3% (29/37) of diabetic patients the scintigraphic study showed myocardial ischemia, while it was negative in the 21.7%. The cardiac event rate in both groups was 6%. In diabetics with a myocardial perfusion study with myocardial ischemia, there were 3 major cardiac events. In diabetic patients with negative study had no cardiac event. In the non-diabetic control group the cardiac events rate was 3.4% (1/29). ConclusionIn diabetic patients without obstructive coronary disease, myocardial perfusion study can be predictor of cardiac events. A negative study can be an indicator of a better cardiovascular prognosis.

Evaluating the effectiveness of a single CT method for attenuation correction in stress-rest myocardial perfusion imaging with thallium-201 chloride SPECT.

This study aimed to evaluate the effectiveness of a single computed tomography (CT) based attenuation correction method using thallium-201 chloride (201TlCl) in stress-rest myocardial perfusion imaging (MPI). The data of 106 patients who underwent MPI with single photon emission computed tomography (SPECT) using 201TlCl were retrospectively reviewed. MPI SPECT images were reconstructed using stress SPECT and stress CT (SIO), rest SPECT and rest CT (RIO), and rest SPECT and stress CT (RIA). The accuracy of alignment between the SPECT and CT images was evaluated with normalized cross-correlation (NCC) and visual examination. The summed rest score (SRS) was used to evaluate hypoperfusion at rest; washout rate (WO) was used to assess ischemia; and left ventricular ejection fraction (LVEF) was used to evaluate the left ventricle (LV) function. There was no significant difference in NCC and visual evaluation in all three dimensions. The SRS of both RIO and RIA (7.5 ± 7.7 and 7.7 ± 7.6, respectively) did not differ significantly. However, SRSs of RIO and RIA showed a strong correlation (r = 0.98). The WO was 39.0 ± 0.98% for both RIO and RIA, with a strong correlation between the two values (r = 1.00). LVEF was 61.1 ± 17.4% for RIO and 61.3 ± 17.4% for RIA, and a strong correlation was observed between the two values (r = 1.00). In conclusion, the single CT-based attenuation correction method with 201TlCl SPECT has an accuracy equivalent to that of the conventional two CT-based attenuation correction method.

Coronary vascular age: An alternate means for predicting stress-induced myocardial ischemia in patients with suspected coronary artery disease

BackgroundCoronary artery calcium (CAC) can be used to estimate vascular age in adults, providing a convenient transformation of CAC from Agatston units into a year’s scale. We investigated the role of coronary vascular age in predicting stress-induced myocardial ischemia in subjects with suspected coronary artery disease (CAD). MethodsA total of 717 subjects referred to CAC scoring and 82Rb PET/CT stress-rest myocardial perfusion imaging for suspected CAD were studied. CAC score was measured according to the Agatston method and coronary vascular age by equating estimated CAD risk for chronological age and CAC using the formula 39.1 + 7.25 × ln(CAC + 1). ResultsStress-induced ischemia was present in 105 (15%) patients. Mean chronological age, CAC score, and coronary vascular age were higher (all P < .001) in patients with ischemia compared to those without. At incremental analysis, the global Chi square increased from 41.26 to 68.77 (P < .001) when chronological age was added to clinical variables. Including vascular age in the model, the global Chi square further increased from 68.77 to 106.38 (P < .001). Adding chronological age to clinical data, continuous net reclassification improvement (cNRI) was 0.57, while adding vascular age to clinical data and chronological age cNRI was 0.62. At decision curve analysis, the model including vascular age was associated with the highest net benefit compared to the model including only clinical data, to the model including chronological age and clinical data, and to a strategy considering that all patients had ischemia. The model including vascular age also showed the largest reduction in false-positive rate without missing any ischemic patients. ConclusionsIn subjects with suspected CAD, coronary vascular age is strongly associated with stress-induced ischemia. The communication of a given vascular age would have a superior emotive impact improving observance of therapies and healthier lifestyles.

Complete revascularization determined by myocardial perfusion imaging could improve the outcomes of patients with stable coronary artery disease, compared with incomplete revascularization and no revascularization

ObjectivesTo compare the outcomes among patients treated by complete coronary revascularization (CCR) or incomplete coronary revascularization (ICR) and no coronary revascularization (NCR) by myocardial perfusion imaging (MPI), as well as to evaluate the impact of severity of ischemia on patients with coronary artery disease (CAD) by different therapy strategies. BackgroundUsing myocardial ischemia severity determined by MPI guiding treatment strategies for CAD patients still lacks strong clinical evidences. MethodsConsecutive patients (N = 286) underwent clinical stress-rest SPECT MPI and were retrospectively followed-up. For assessment of outcome of treatment, all patients were classified into three groups (CCR, ICR, and NCR), and further divided into two subgroups as mild ischemia (< 10% ischemic myocardium) and moderate-severe ischemia (≥ 10% ischemic myocardium). All-cause death was defined as the primary endpoint, and the composite of deaths, nonfatal myocardial infarction, and repeat revascularization (MACE) as the secondary endpoint. ResultsTwo-hundred eighty-six patients were followed-up for 46 ± 21 months. Thirty deaths and 65 MACEs were recorded. Patients treated by revascularization had significantly lower MACE (P < .001) but not mortality (P = .158) than patients treated by NCR. Outcomes of CCR related to mortality rate were greater than ICR and NCR (death: P = .019, MACE: P < .001). In patients with moderate-severe ischemia, CCR showed improved outcomes than ICR and NCR (death: P = .034; and MACE: P < .001). In patients with mild ischemia, the outcomes of CCR, ICR, and NCR had no significant difference (P > .05). Multivariate regression Cox analysis revealed that summed difference score [death: HR 1.09 (1.03, 1.15), P = .004] was an independent risk factor and CCR was an independent negative predictor [death: HR 0.31 (0.12, 0.81), P = .017; MACE: HR 0.30 (0.16, 0.57), P < .001]. ConclusionsOutcomes of patients treated by CCR were most likely more promising in comparison with treatment of ICR and NCR, especially when patients had over 10% ischemic myocardium.

P389Microvascular dysfunction in type 2 diabetic patients with normal rest-stress myocardial perfusion imaging

P389Microvascular dysfunction in type 2 diabetic patients with normal rest-stress myocardial perfusion imaging

Accuracy of cadmium-zinc-telluride imaging in detecting single and multivessel coronary artery disease: Is there any gender difference?

PurposeTo evaluate gender-related differences in diagnostic accuracy of cadmium‑zinc-telluride (CZT) myocardial perfusion imaging in detecting single- and multi-vessel coronary artery disease (CAD). MethodsWe prospectively enrolled 1161 consecutive patients with known or suspected coronary artery disease (288, 25% women and 873, 75% men) who had been referred to our laboratory for stress–rest myocardial perfusion imaging (single-day stress–rest protocol, mean radiation dose: 4 mSv). All patients underwent coronary angiography within 30 days; significant CAD was defined in the presence of a coronary stenosis >70%. Summed stress scores (SSS), summed rest scores (SRS) and summed difference scores (SDS) were obtained. Image quality was graded “good” or better in >90% of patients. ResultsOn coronary angiography, left main trunk, left anterior descending artery, left circumflex artery and right coronary artery obstructive stenosis were seen in 13, 486, 393 and 499 patients, respectively. Global SSS was the best predictor of CAD in women (AUC = 0.866, 81% sensitivity and 79% specificity) and in men (AUC = 0.871, 76% sensitivity and 84% specificity). Interestingly, its accuracy was maintained also in patients with two-vessel (women: AUC = 0.842, p < 0.001; men: AUC 0.839, p < 0.001) or three-vessel disease (women: AUC = 0.800, p < 0.001; men: AUC 0.804, p < 0.001). There was no gender-related difference in terms of diagnostic accuracy. ConclusionsEvaluation of multivessel disease can be obtained by CZT camera in men as well as in women, with high accuracy at a lower radiation exposure.

Value of automatic patient motion detection and correction in myocardial perfusion imaging using a CZT-based SPECT camera

BackgroundCorrection of motion has become feasible on cadmium-zinc-telluride (CZT)-based SPECT cameras during myocardial perfusion imaging (MPI). Our aim was to quantify the motion and to determine the value of automatic correction using commercially available software. Methods and ResultsWe retrospectively included 83 consecutive patients who underwent stress-rest MPI CZT-SPECT and invasive fractional flow reserve (FFR) measurement. Eight-minute stress acquisitions were reformatted into 1.0- and 20-second bins to detect respiratory motion (RM) and patient motion (PM), respectively. RM and PM were quantified and scans were automatically corrected. Total perfusion deficit (TPD) and SPECT interpretation—normal, equivocal, or abnormal—were compared between the noncorrected and corrected scans. Scans with a changed SPECT interpretation were compared with FFR, the reference standard. Average RM was 2.5 ± 0.4 mm and maximal PM was 4.5 ± 1.3 mm. RM correction influenced the diagnostic outcomes in two patients based on TPD changes ≥7% and in nine patients based on changed visual interpretation. In only four of these patients, the changed SPECT interpretation corresponded with FFR measurements. Correction for PM did not influence the diagnostic outcomes. ConclusionRespiratory motion and patient motion were small. Motion correction did not appear to improve the diagnostic outcome and, hence, the added value seems limited in MPI using CZT-based SPECT cameras.

IQ-SPECT for thallium-201 myocardial perfusion imaging: effect of normal databases on quantification

Although IQ-single-photon emission computed tomography (SPECT) provides rapid acquisition and attenuation-corrected images, the unique technology may create characteristic distribution different from the conventional imaging. This study aimed to compare the diagnostic performance of IQ-SPECT using Japanese normal databases (NDBs) with that of the conventional SPECT for thallium-201 (201Tl) myocardial perfusion imaging (MPI). A total of 36 patients underwent 1-day 201Tl adenosine stress-rest MPI. Images were acquired with IQ-SPECT at approximately one-quarter of the standard time of conventional SPECT. Projection data acquired with the IQ-SPECT system were reconstructed via an ordered subset conjugate gradient minimizer method with or without scatter and attenuation correction (SCAC). Projection data obtained using the conventional SPECT were reconstructed via a filtered back projection method without SCAC. The summed stress score (SSS) was calculated using NDBs created by the Japanese Society of Nuclear Medicine working group, and scores were compared between IQ-SPECT and conventional SPECT using the acquisition condition-matched NDBs. The diagnostic performance of the methods for the detection of coronary artery disease was also compared. SSSs were 6.6±8.2 for the conventional SPECT, 6.6±9.4 for IQ-SPECT without SCAC, and 6.5±9.7 for IQ-SPECT with SCAC (p=n.s. for each comparison). The SSS showed a strong positive correlation between conventional SPECT and IQ-SPECT (r=0.921 and p<0.0001), and the correlation between IQ-SPECT with and without SCAC was also good (r=0.907 and p<0.0001). Regarding diagnostic performance, the sensitivity, specificity, and accuracy were 80.8, 78.9, and 79.4%, respectively, for the conventional SPECT; 80.8, 80.3, and 82.0%, respectively, for IQ-SPECT without SCAC; and 88.5, 86.8, and 87.3%, respectively, for IQ-SPECT with SCAC, respectively. The area under the curve obtained via receiver operating characteristic analysis were 0.77, 0.80, and 0.86 for conventional SPECT, IQ-SPECT without SCAC, and IQ-SPECT with SCAC, respectively (p=n.s. for each comparison). When appropriate NDBs were used, the diagnostic performance of 201Tl IQ-SPECT was comparable with that of the conventional system regardless of different characteristics of myocardial accumulation in the conventional system.