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WOS: 000472637800002, Objectives: In this study our first aim was to evaluate the diagnostic concordance of myocardial perfusion scintigraphy (MPS) by pharmacological stress test with adenosine (APST) with coronary angiography (CAG). The secondary aim of this study was to evaluate the correlation between CAG findings and automated analysis parameters such as left ventricular ejection fraction, summed stress score (SSS), summed rest score, summed difference score (SDS), stress MPS defect percentage ratio (extent) and transient ischemic dilation (TID) obtained by myocardial perfusion imaging single-photon emission computed tomography (SPECT). Methods: A total of 129 patients (62 male, 67 female, median age: 60.02) undergoing MPS due to suspicion of coronary ischemia who also underwent subsequent CAG in the last year were included in this study, their MPS data and CAG results were compared. Results: There was no statistically significant diagnostic concordance when visual evaluation of MPS, quantitative MPS parameters and exercise treadmill test (ETT) electrocardiography results were used alone. In fact, diagnostic concordance was higher when automated analysis parameters like TID, SSS and extent values were added to MPS SPECT visual analyses. There was diagnostic concordance in 57.9% of APST patients and 41.7% of ETT patients. There was diagnostic concordance in 75.8% of APST patients and 52.6% of ETT patients who were older than 65 years of age. Conclusion: In our study, we found that the use of APST during MPS increases diagnostic concordance with CAG. Therefore, we think that it would be appropriate to use APST in women and elderly patients with limited exercise habits. The CAG diagnostic mismatch is far above what it should be when MPS reporting is only done with visual data, and it is not supported by quantitative data such as TID, SSS, SDS and extent.

Transient ischemic dilation (TID) is a sensitive and specific marker for detecting the severity and extent of coronary artery disease (CAD), which is closely associated with endothelial dysfunction. TID can be observed on stress-rest myocardial perfusion scan (MPS) due to subendocardial hypoperfusion. Hyperglycemia in type 2 diabetes mellitus (T2DM) could lead to micro- and macrovascular complications and begins with endothelial dysfunction. Endothelin-1 (ET-1), a potent vasocontrictor, increases in endothelial dysfunction. The aim of this study was to examine the correlation between TID index and ET​​-1 levels in T2DM patients without any sign or symptom of cardiovascular complication. An analytic-correlational cross-sectional study was done on T2DM patients who met the inclusion criteria and agreed to participate by signing an informed consent form. The TID index was calculated automatically using standard software provided by the gamma camera GE-Infinia. Stress-rest MPS was done using technetium-99m ( 99m Tc)-tetrofosmin and a pharmacological stress test using adenosine. The ET-1 level was determined by radioimmunoassay. Data distribution was analyzed using the Shapiro-Wilk normality test. The Mann-Whitney test was used to compare the average difference of the variables and Spearman′s rank for correlation analysis. A total of 47 subjects consisting of 24 (51%) males and 23 (49%) females were included in this study. The age range was 37-74 years (54.3 ± 8.4). The TID index range was 0.86-1.26 (median = 1.12) and abnormal TID index was found in 23/47 (49%) subjects. ET-1 levels range 8.02-17.91 pg/mL (median = 11.08). The results showed no significant differences in age, ET-1 levels, and TID index based on age and sex (P > 0.05). There was a significant positive correlation between TID index and ET-1 level with r = 0.7 and P < 0.001. There was a positive correlation between TID index and ET-1 plasma level in patients with T2DM.

Objective: The causes and prognostic significance of the reverse redistribution pattern (RRP) is not clear yet. In this study, we aimed to evaluate the RRP effect on the left ventricular ejection fraction (EF). Methods: Imaging of the patients whose technetium-99m sestamibi myocardial perfusion scintigraphy was carried out and reported as normal were retrospectively examined. One-day protocol and/or pharmacologic stress testing applied patients were excluded. 21 patients with RRP met the inclusion criteria. All of these patients were included in the study as RRP group. Randomly selected 21 patients with non-RRP were included in the study as control group. Transient ischemic dilation (TID) scores and EF values were automatically calculated with the Quantitative Gated SPECT (QGS) program. Results: While a statistically significant difference was not found between the RRP and control groups in terms of age, sex, hypertension, family history, hyperlipidemia, and diabetes (p>0.05), there was a statistically significant difference in terms of smoking (p=0.019). TID scores in the RRP group were significantly lower compared to the control group (p

The critical threshold and clinical significance of transient ischemic dilation (TID) for regadenoson, single-isotope 99mTc SPECT myocardial perfusion imaging (MPI) are not defined. From 100 patients with low likelihood of CAD, we derived the abnormal TID threshold (mean + 2 SD). We validated the threshold in a cohort of 547 patients who received one-day, rest/regadenoson-stress, 99mTc-tetrofosmin SPECT-MPI followed by coronary angiography within 6 months. Patients were classified into three CAD severity strata: no significant CAD, mild to moderate CAD, and severe and extensive CAD. The abnormal TID threshold was determined to be 1.31. Though mean TID ratios were different between the three CAD severity groups and the derivation cohort (P

Cardiovascular disease is the leading cause of death in patients with end-stage renal disease (ESRD) and often goes undetected. Abnormal coronary flow reserve (CFR), which predicts increased risk of cardiac death, may be present in patients with ESRD without other evidence of coronary artery disease (CAD). We prospectively studied 131 patients who had rest and dipyridamole pharmacologic stress N13-ammonia positron emission tomography myocardial perfusion imaging (PET MPI) for kidney transplant evaluation. Thirty-four patients also had left heart catheterization. Abnormal PET MPI was defined as qualitative ischemia or infarct, stress electrocardiogram ischemia, or transient ischemic dilation. CFR was calculated as the ratio of stress to rest coronary blood flow. Global CFR

Transient ischemic dilation (TID) in the setting of abnormal stress–rest cardiac SPECT myocardial perfusion imaging (MPI) has been linked with increased cardiovascular risk. However, the significance of TID in the setting of an otherwise normal SPECT MPI study has not been clearly established. In this study, cardiac CT was used to evaluate the prevalence of atherosclerotic lesions and the severity of coronary artery stenosis in patients with TID of the left ventricle with or without associated myocardial perfusion defects on SPECT MPI. Methods: The study population consisted of 1,553 consecutive patients who had undergone both cardiac CT and SPECT MPI within 1 mo between January 1, 2006, and September 1, 2011. Patients included in the study group had a pathologic TID value defined as ≥1.18 for men and ≥1.22 for women. Coronary CT angiography was used to evaluate each coronary segment for the presence and composition of atherosclerotic plaque and the degree of coronary stenosis. TID-positive patients were compared with a 2:1 risk-factor-matched-pair control cohort without TID. Results: TID was identified in 30 patients who were compared with TID-negative risk-factor-matched controls (n = 60). When compared with the TID-negative control cohort, TID-positive patients had no significant differences in the presence and extent of atherosclerosis, the degree of coronary artery stenosis, or the calcium score at cardiac CT. Similarly, there were no significant differences in these CT measures in TID-positive patients with a normal perfusion study (n = 20) when compared with TID-negative patients with a normal perfusion study (n = 48). In addition, there was no significant difference in the incidence of major adverse cardiac events when comparing both the TID-positive patients and the TID-negative control cohort and when comparing patients who were TID-positive with normal perfusion with patients who were TID-negative with normal perfusion. Conclusion: The presence of TID with an otherwise normal SPECT MPI study does not translate into a greater extent of coronary artery disease as assessed by cardiac CT or increased risk for future major adverse cardiac events.

Introduction The current guidelines for CAD suggest that patients with moderate to severe ischemia should be referred for angiography and possible revascularization, while patients with mild ischemia can be safely treated medically. These recommendations are currently being tested in the ISCHEMIA trial. It is unclear how often patients with moderate to severe ischemia are referred to coronary angiography. The aim of this study is to identify the rate and predictors of referral to coronary angiography post MPI. Methodology A retrospective cohort study included patients with suspected or known CAD who were referred to PET-CT imaging MPI due various clinical indications between May 2011 and March 2017. Ischemic burden was measured by the sum difference score. Moderate to severe ischemia was defined by summed stress score more than 7. Results A total of 5060 patients were included. Approximately, one third of patients had prior coronary disease. The prevalence and extent of ischemia was higher among patients with previous coronary disease. Chest pain or shortness of breath was the most common indication for referral to MPI. Patients who had severe ischemia, nearly 70% of them were referred to coronary angiography within 90 days and 76.6% were referred to coronary angiography within one year. However patients with moderate ischemia were much less often referred to coronary angiography and less than half of these patients were referred to coronary angiography within 90 days. The independent predictors of referral to coronary angiography within 90 days among all patients were age, CAD, transient ischemic dilation and presence and degree of ischemia. Conclusion This study found that the increase in patient’s age, Summed Different Score, Transient Ischemic Dilation, ischemia group, and having CAD can predict an increased in the coronary angiography referral, and CVA is a protective factor for referral to coronary angiography.

Background— We prospectively evaluated the incremental prognostic value of transient ischemic dilation (TID) in patients with type 2 diabetes mellitus during long-term follow-up and estimated cardiac death and nonfatal myocardial infarction (MI) using traditional approaches of prognostication to more recent methods. Methods and Results— A total of 672 consecutive diabetic patients with available rest and stress gated myocardial perfusion single-photon emission computed tomographic data were enrolled. Stepwise Cox regression analysis was used to estimate cardiac death or nonfatal MI. Risk reclassification was calculated, and an exploratory analysis was performed to evaluate the effect of coronary revascularization on event-free survival. Adding TID to a multivariable model, including age, history of MI, stress type, poststress left ventricular ejection fraction, and stress-induced myocardial ischemia, improved discrimination of cardiac death or nonfatal MI (C statistic, 0.74–0.82; P =0.01; adjusted hazard ratio, 3.6; P P P Conclusions— TID provides independent and incremental prognostic information for the prediction of cardiac death or nonfatal MI in patients with diabetes mellitus. The addition of TID to a prediction model based on cardiovascular risk factors, left ventricular ejection fraction, and ischemia significantly improves risk discrimination and reclassification for incident cardiac events. The effect of revascularization seems to be influenced by left ventricular systolic function, stress-induced myocardial ischemia, and TID.

Context: Transient ischemic dilatation (TID) of the left ventricle is a non-invasive marker of suspected or known Coronary Artery Disease (CAD), and is used for the prediction of prognosis. Because the value of TID has been emphasized by current publications in clinical nuclear cardiology field, the current review of the literature was conducted to present comprehensive overview on the findings in this field. Evidence Acquisition: Relevant literature was obtained by searching online databases, including MEDLINE/PubMed, Google Scholar, and Science Direct using the following keywords: transient ischemic dilation, Single Photon Emission Computed Tomography Myocardial Perfusion Imaging (SPECT MPI), procedural guidelines for myocardial perfusion imaging, and coronary artery disease. Articles were inspected to obtain good agreement criteria pertinent to the objective of the study. Overall, 21 relevant articles were selected to be included in the review. Results: Stress-induced subendocardial hypoperfusion, post-ischemic stunning, and impaired coronary flow reserve have been reported as common causes of TID. Transient Ischemic Dilatation can be easily measured by available automatic software on the market, including Emory Cardiac Toolbox, 4D-MSPECT, etc. A close correlation between TID and LV volume/function has been emphasized by previous researchers. Transient Ischemic Dilatation, in the setting of a cardiac SPECT MPI with abnormal findings, has been known to be a robust indicator of severe/extensive CAD and future cardiac events. However, only a limited number of publications are available for its probable use in the setting of normal MPI, especially based on patients at high-risk and those with TID. Conclusions: By using an upper limit value of TID that is derived according to the optimum imaging procedure of a particular laboratory, routine reporting of TID measurement as part of conventional SPECT MPI analysis may be useful.

Background Transient ischemic dilatation (TID) of the left ventricle is a potential marker of high risk obstructive coronary artery disease on stress myocardial perfusion imaging (MPI). There is, however, interstudy variation in the diagnostic performance of TID for identification of severe and extensive coronary disease anatomy, and varied prognostic implications in the published literature. Methods We searched MEDLINE, EMBASE, and COCHRANE databases for studies where TID was compared with invasive or CT coronary angiography for evaluation of coronary artery stenosis. Two reviewers independently evaluated and abstracted data from each study. A bivariate random effects model was used to derive pooled sensitivities and specificities, in order to account for correlation between TID in MPI and anatomic disease severity. Results A total of 525 articles were reviewed, of which 51 met inclusion criteria. Thirty-one studies contributed to the analysis, representing a total of 2037 patients in the diagnostic meta-analysis and 9003 patients in the review of prognosis. The ratio above which TID was deemed present ranged from 1.13 to 1.38. Pooled sensitivity was 44% (95% CI 30%-60%) and specificity was 88% (95% CI 83%-92%) for the detection of extensive or severe anatomic coronary artery disease. Analysis of outcome data demonstrated increased cardiac event rates in patients with TID and an abnormal MPI. In otherwise normal perfusion, TID is an indicator of poor prognosis in patients with diabetes and/or a history of coronary disease. Conclusions Among patients undergoing MPI, the presence of TID is specific for the detection of extensive or severe coronary artery disease. Electronic supplementary material The online version of this article (doi:10.1007/s12350-017-1040-7) contains supplementary material, which is available to authorized users.

In myocardial perfusion SPECT, transient ischemic dilation ratio (TID) is a well-established marker of severe ischemia and adverse outcome. However, its role in the setting of (82)Rb PET is less well defined.We analyzed 265 subjects who underwent clinical rest-dipyridamole (82)Rb PET/CT. Sixty-two subjects without a prior history of cardiac disease and with a normal myocardial perfusion study had either a low or a very low pretest likelihood of coronary artery disease or negative CT angiography. These subjects were used to establish a reference range of TID. In the remaining 203 patients with an intermediate or high pretest likelihood, subgroups with normal and abnormal TID were established and compared with respect to clinical variables, perfusion defect scores, left ventricular function, and absolute myocardial flow reserve. Follow-up was obtained for 969 ± 328 d to determine mortality by review of the social security death index.In the reference group, TID ratio was 0.98 ± 0.06. Accordingly, a threshold for abnormal TID was set at greater than 1.13 (0.98 + 2.5 SDs). In the study group, 19 of 203 patients (9%) had an elevated TID ratio. Significant differences between subgroups with normal and abnormal TID ratio were observed for ejection fraction reserve (5.0 ± 6.4 vs. 1.8 ± 7.9; P0.05), difference between end-systolic volume (ESV) at rest and stress (ΔESV[stress-rest]; 1.8 ± 7.4 vs. 12.3 ± 13.0 mL; P0.0001), difference between end-diastolic volume (EDV) at rest and stress (ΔEDV[stress-rest]; 10.8 ± 11.5 vs. 23.8 ± 14.6 mL; P0.0001), summed rest score (1.8 ± 3.8 vs. 3.8 ± 7.6; P0.05), summed stress score (3.0 ± 5.4 vs. 7.5 ± 9.8; P0.002), summed difference score (1.3 ± 2.6 vs. 3.7 ± 5.3; P0.02), and global myocardial flow reserve (2.1 ± 0.8 vs. 1.7 ± 0.6; P0.02). Additionally, TID-positive patients had a significantly lower overall survival probability (P0.05). In a subgroup analysis of patients without regional perfusion abnormalities, TID-positive patients' overall survival probability was significantly smaller (P0.03), and TID was an independent predictor (exponentiation of the B coefficients [Exp(b)] = 6.22; P0.009) together with an ejection fraction below 45% (Exp[b] = 6.16; P0.002).The present study suggests a reference range of TID for (82)Rb PET myocardial perfusion imaging that is in the range of previously established values for SPECT. Abnormal TID in (82)Rb PET is associated with more extensive left ventricular dysfunction, ischemic compromise, and reduced global flow reserve. Preliminary outcome analysis suggests that TID-positive subjects have a lower overall survival probability.

Transient ischemic dilation (TID) of the left ventricle in myocardial perfusion SPECT (MPS) has been shown to be a clinically useful marker of severe coronary artery disease (CAD). However, TID has not been evaluated for 99mTc-sestamibi rest/stress protocols (Mibi-Mibi). We aimed to develop normal limits and evaluate diagnostic power of TID ratio for Mibi-Mibi scans.TID ratios were automatically derived from static rest/stress MPS (TID) and gated rest/stress MPS from the end-diastolic phase (TID(ed)) in 547 patients who underwent Mibi-Mibi scans [215 patients with correlating coronary angiography and 332 patients with low likelihood (LLk) of CAD]. Scans were classified as severe (≥ 70% stenosis in proximal left anterior descending (pLAD) artery or left main (LM), or ≥ 90% in ≥ 2 vessels), mild to moderate (≥ 90% stenosis in 1 vessel or ≥ 70%-90% in ≥ 1 vessel except pLAD or LM), and normal (70% stenosis or LLk group). Another classification based on the angiographic Duke prognostic CAD index (DI) was also applied: DI ≥ 50, 30 ≤ DI50 and DI30 or LLk group.The upper normal limits were 1.19 for TID and 1.23 for TID(ed) as established in 259 LLk patients. Both ratios increased with disease severity (P.0001). Incidence of abnormal TID increased from 2% in normal patients to36% in patients with severe CAD. Similarly, when DI was used to classify disease severity, the average ratios showed significant increasing trend with DI increase (P.003); incidence of abnormal TID also increased with increasing DI. The incidence of abnormal TID in the group with high perfusion scores significantly increased compared to the group with low perfusion scores (stress total perfusion deficit, TPD3%) (P.0001). The sensitivity for detecting severe CAD improved for TID when added to mild to moderate perfusion abnormality (3% ≤ TPD10%): 71% vs 64%, P.05; and trended to improve for TID(ed)/TID(es): 69% vs 64%, P = .08, while the accuracy remained consistent if abnormal TID was considered as a marker in addition to stress TPD. Similar results were obtained when DI was used for the definition of severe CAD (sensitivity: 76% vs 66%, P.05 when TID was combined with stress TPD).TID ratios obtained from gated or ungated Mibi-Mibi MPS and are useful markers of severe CAD.

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. Methods and Results: A total of 278 patients with suspected or confirmed CAD underwent both exercise stress 99mTc-sestamibi gated single-photon emission computed tomography and coronary angiography. LV mechanical dyssynchrony was evaluated using the SyncTool to obtain the phase SD and histogram bandwidth. In the detection of 128 patients with multivessel CAD, a summed stress score (SSS) of ≥9 showed a sensitivity of 84% and a specificity of 53%, while an increase in phase SD of ≥4.4° and a bandwidth of ≥14° after exercise had sensitivities of 74% and 68%, and specificities of 84% and 91%, respectively. On multivariate analysis the combination of post-stress increases in phase SD, histogram bandwidth, transient ischemic dilation (TID) ratio and SSS best identified multivessel CAD (sensitivity 77%, specificity 88%, χ2=181.8), compared with TID ratio and SSS only (sensitivity 70%, specificity 76%, χ2=68.9). Conclusions: The addition of phase analysis to evaluate exercise-induced LV mechanical dyssynchrony on conventional perfusion analysis enabled better identification of patients with multivessel CAD. (Circ J 2012; 76: 1942–1952)

Background: Although poststress myocardial stunning is regarded as a marker for severe coronary artery disease (CAD), no study has yet compared the diagnostic value of poststress stunning with transient ischemic dilation (TID) of the left ventricle (LV) for detecting multivessel CAD. Methods and Results: A total of 271 patients with suspected or known CAD underwent adenosine triphosphate (ATP) loading and at-rest gated single-photon emission computed tomography. We assessed myocardial perfusion with a 20-segment model, and analyzed the changes in LV volumetric analysis induced by ATP and an automatically derived TID ratio. In 147 patients with multivessel CAD, the prevalence of multi-territorial ischemia was higher, and the post-ATP increase in end-systolic volume (ESV) and TID ratio were greater, than in the 124 with insignificant or single-vessel CAD (P

SummaryBackgroundWe sought to explore the value of stress-induced transient ischemic dilation (TID) of the left ventricle during dobutamine stress echocardiography, to predict the presence of multi-vessel coronary artery disease as seen by coronary angiography.MethodsWe enrolled 60 patients referred to our stress echocardiography labs with ischemic-type chest pain or other symptoms suggestive of myocardial ischemia. All patients underwent resting and stress echocardiography employing the standard dobutamine stress protocol. TID ratio was defined as the ratio of left ventricular end-diastolic volume or end-systolic volume measured at peak stress, to that measured at rest (EDV ratio and ESV ratio, respectively). We enrolled 20 consecutive patients with normal response (control group) who were subsequently evaluated to develop normal limits for TID ratio, and 40 patients with ischemic response (study group) that comprised 20 consecutive patients without TID (group A) and 20 consecutive patients with TID (group B). Patients then underwent coronary angiography.ResultsBoth EDV ratio and ESV ratio were significantly higher in groups A and B as compared to the control group (P

Reducing acquisition time may improve patient throughput, increase camera efficiency, and reduce costs; reducing acquisition time also increases image noise. Newly available software controls the effects of noise by maximum a posteriori reconstruction while maintaining resolution with resolution-recovery methods. This study compares half-time (HT) gated myocardial SPECT images processed with ordered-subset expectation maximization with resolution recovery (OSEM-RR) (with and without CT-based attenuation correction [AC]) with full-time (FT) images obtained with a standard clinical protocol and reconstructed with filtered backprojection (FBP) and OSEM (with and without AC).A total of 212 patients (mean age, 57 y; age range, 27-86 y) underwent 1-d rest/stress (99m)Tc-tetrofosmin gated SPECT. FT (12.5 min, both rest and stress) and HT (rest, 7.5 min; stress, 6.0 min) images were acquired with low-dose CT for AC in 112 patients. HT acquisitions were processed with OSEM-RR (with and without AC) using software, and FT acquisitions were processed with FBP and OSEM (with and without AC). In another 100 patients, test-retest repeatability was assessed using 2 sets of FT images (FBP reconstruction) that were acquired one immediately after the other. Radiologists unaware of the acquisition and reconstruction protocols visually assessed all reconstructed images for summed stress, summed rest, and summed difference scores and regional wall motion using a 17-segment model. Automated analysis on gated SPECT was used to determine left ventricular volumes, ejection fraction, and dilation (end-diastolic volume, end-systolic volume, left ventricular ejection fraction, and transient ischemic dilation [TID]). A clinical diagnosis was also determined.All measurements resulted in significant correlations (P0.01) between the HT and FT images. The only significant difference in mean values was for OSEM-RR plus AC; this method led to an increase in TID by 4% over FT imaging. The concordance in the clinical diagnosis for HT versus FT was 106 to 112 (kappa = 0.88) for no AC and 102 to 106 (kappa = 0.91) for AC, similar to the repeatability of FT versus FT (98/100, kappa = 0.95).HT images processed with the new algorithm provided a clinical diagnosis in concordance with that from FT images in 95% (no AC) to 96% (AC) of cases. This concordance is similar to the test-retest repeatability of FT imaging.

Background Although transient left ventricular (LV) dilation is a well-known marker for extensive coronary artery disease (CAD), few studies performed quantitative analysis of LV function of post adenosine triphosphate (ATP) stress and at rest to detect extensive CAD.

Background. Diabetes and left ventricular hypertrophy (LVH) can cause coronary flow reserve abnormalities in the absence of coronary artery disease (CAD). We sought to evaluate the impact of LVH and diabetes on the relationship between ischemia, severe CAD, and transient ischemic dilation (TID) on adenosine myocardial perfusion imaging (MPI). Methods and Results. We prospectively recruited 157 patients referred for routine single-day adenosine technetium 99m MPI. LVH was assessed by use of transthoracic echocardiography. A ratio of 1.19 or greater on MPI defined TID in men and 1.31 or greater in women. Summed difference scores were determined by use of a 17-segment 5-point scoring system. TID was present in 22 of 157 patients (14%), diabetes in 54 of 157 (34%), and LVH in 42 of 157 (27%). By multivariate logistic regression, LVH, ischemia (summed difference score >2), and diabetes were independently predictive of TID. The incidence of TID was stratified by the presence or absence of diabetes and/or LVH in those with ischemia on MPI (8/8 [100%] vs 0/11 [0%], P

SummaryObjectivesAlthough the Heston index, derived left ventricular (LV) volumetric analysis, is reported to best represent transient LV dilation on non-gated single-photon emission computed tomography (SPECT), its diagnostic performance has not been proven to identify extensive coronary artery disease (CAD) as assessed by coronary angiogram. Accordingly, we sought to evaluate the diagnostic utility of Heston index to detect multi-vessel CAD.MethodsPost-stress and resting electrocardiogram-gated 99mTc-sestamibi SPECT was performed in 223 patients with suspected or known CAD. All of the patients underwent coronary angiography within 3 months of gated SPECT. The summed stress, summed rest, and summed difference scores were calculated using a 20-segment model. The left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) were calculated automatically with the QGS program. In addition, stress-to-rest ratios of EDV, ESV, and (ESV×5+EDV) were calculated; the latter was defined as Heston index.ResultsIn the 104 patients with multi-vessel CAD, the summed stress score (17.5±10.0 vs. 11.7±9.2, p

Transient ischemic dilation (TID) of the left ventricle (LV) has not been validated as a marker of extensive coronary artery disease (CAD) for studies using a cadmium-zinc-telluride (CZT) camera with upright imaging. TID ratios were obtained from upright stress and rest images on a CZT camera. Separate cut-off values were determined for exercise and for regadenoson stress. The cutoffs were then applied to 28 patients with extensive CAD and 101 patients without extensive CAD. With treadmill exercise, an upright TID ratio ≥1.16 provided a positive predictive value of 50% and a negative predictive value of 85.4% for the identification of extensive CAD. In the regadenoson group, an upright TID ratio of 1.29 provided a positive predictive value of 20% and a negative predictive value of 75.9%. Although not an independent predictor of extensive CAD in all subjects, in subjects with a normal upright LVEF, it provided a predictive value by receiver operating characteristics comparable to the SSS. Increased upright TID measurements on a CZT camera are associated with extensive CAD. The upright TID measurements can serve in an adjunctive role to SSS, and may be most effective in patients with a normal upright exercise LVEF.

Background There have been limited data regarding the value of gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) for the detection of left main coronary artery disease (CAD). Methods and Results We studied 101 patients with angiographic left main CAD (≥50% stenosis) and no prior myocardial infarction or coronary revascularization who underwent gated exercise or adenosine stress technetium 99m sestamibi SPECT MPI. By perfusion assessment alone, high-risk disease with moderate to severe defects (>10% myocardium at stress) was identified in only 56% of patients visually and 59% quantitatively. Absence of significant perfusion defect (≥5% myocardium) was seen in 13% of patients visually and 15% quantitatively. However, by combining visual perfusion data and nonperfusion variables, especially transient ischemic dilation, 83% of patients were identified as high risk. Conclusions The findings of this study demonstrate that assessment of perfusion data alone by visual or quantitative SPECT MPI analysis underestimates the magnitude of left main CAD. The combination of perfusion and nonperfusion abnormalities on gated MPI identifies high risk in most patients with left main CAD.

The definition of an abnormal transient ischemic dilation (TID) ratio may be different according to stress type, type of isotope, and imaging protocols. The aim of this study was to derive the normal threshold and assessment of the TID ratio via 2-day dipyridamole stress/rest technetium 99m sestamibi myocardial perfusion single photon emission computed tomography (MPS).We performed 2-day dipyridamole stress/rest Tc-99m sestamibi MPS in 665 patients. The TID ratio was calculated automatically with the Emory Cardiac Toolbox. The upper limit of normal (1.19) for the TID ratio was derived from 131 patients with a low (5%) likelihood of coronary artery disease as mean + 2 SDs. Patients with complete or partial reversible defects or multivessel-type or left anterior descending artery (LAD) territory perfusion abnormalities had higher TID ratios than the other patients. These patients had a higher frequency of an abnormal TID ratio (1.19) as well. Binary logistic regression analysis showed that ischemia and LAD territory perfusion abnormality were independent predictors of an abnormal TID ratio.The threshold for an abnormal TID ratio via 2-day post-dipyridamole stress/rest Tc-99m sestamibi MPS was greater than 1.19. By use of this protocol, TID is not uncommon and it is related to a greater amount of ischemic burden as well as multivessel-type or LAD territory perfusion abnormality.

Although transient left ventricular (LV) dilation is a well-known marker for extensive coronary artery disease (CAD), few studies have performed quantitative analysis of LV function after stress and at rest to detect extensive CAD.Poststress and resting gated single photon emission computed tomography (SPECT) was performed in 175 patients with suspected CAD. All of the patients underwent coronary angiography within 3 months of gated SPECT. In the 83 patients with multivessel CAD, the summed difference score was greater (9.2 +/- 7.0 vs 3.3 +/- 4.0, P.0001), the poststress increase in end-systolic volume (ESV) was larger (7.0 +/- 8.0 mL vs -0.8 +/- 4.7 mL, P.0001), and the poststress increase in ejection fraction (EF) was less (-4.7% +/- 5.4% vs -0.4% +/- 4.5%, P.0001) than in the 92 patients with insignificant or single-vessel CAD. In the detection of multivessel CAD, a summed difference score of 9 or greater showed a sensitivity of 46% and specificity of 90%, whereas an increase in ESV of 5 mL or greater and a decrease in EF of 5% or greater after exercise had a sensitivity of 66% and 52%, respectively, and specificity of 87% and 83%, respectively. The multivariate discriminant analysis revealed that the combination of poststress increase in ESV, summed difference score, and diabetes mellitus best identified multivessel CAD, with a sensitivity of 72% and specificity of 84% (chi(2), 81.7).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.

Abnormal values of the transient ischemic dilation ratio (TID) according to an exercise myocardial SPECT are linked to severe coronary artery disease. The authors investigated the relationship between TID and the levels of VCAM, ICAM, E-selectin, microalbuminuria, intima-media thickness and HbA(1c) of diabetic subjects.We observed 38 subjects with diabetes type 2 (10 women, 28 men), of average age 56.08 +/- 8.24 years, with no past history of cardiovascular disease. All subjects were examined using an exercise myocardial SPECT. Transient ischemic dilation, summed stress score (SSS), summed rest score (SRS) and stress total severity score (STSS) were determined to quantify myocardial ischemia.The average IMT value was 1.05 +/- 0.31 mm. The TID value was 1.02 +/- 0.154, VCAM 795.24 +/- 163.25 mg/l, ICAM 516.55 +/- 164.07, E-selectin 63.82 +/- 38.89, HbA(1c) 7.09 +/- 1.68%, microalbuminuria 68.01 +/- 55.21 mg/l. When ascertaining the relation of TID to the other factors we used Pearson's correlation at the level of significance p0.05. We proved a statistically significant correlation between the value of TID and glycosylated hemoglobin HbA(1c) (p = 0.035); the other factors did not show any significant correlation.Diabetes and its long- term unsatisfactory compensation can be one of the factors which affect left ventricular transient ischemic dilation.

Objectives We sought to evaluate the prognostic significance of left ventricular (LV) transient ischemic dilation (TID) for patients with a positive stress echocardiogram (SE). Background TID during SE has been related to the presence of extensive coronary artery disease, but its long-term prognostic implications have not been reported. Methods In all, 99 consecutive patients with a positive SE comprised the study group. LV volumes were evaluated according to the modified Simpson's rule. TID during SE was defined as the presence of an increase in LV end-diastolic volume during the stress test. A clinical history was fulfilled for each patient and all of them were followed up. Results Of 99 patients, 32 (32.3%) showed TID. Mean age was 65.8 ± 9.8 years for non-TID group and 70.2 ± 8.4 for TID group ( P = .048). Baseline characteristics and subsequent treatment were similar in both groups. Mean follow-up was 21.4 ± 15.8 months. In non-TID group the mean survival free of acute myocardial infarction was 47.28 months and 39.7 months in TID group (log rank=0.012). In the univariate and multivariate analysis only TID and the wall motion score index were found as independent predictors related to long-term prognosis (risk ratio=6.9; 95% confidence interval=0.8-59.6; P = .042; and risk ratio=0.4; 95% confidence interval=0.18-0.89; P = .047, respectively). Conclusions LV TID during SE is an easy and independent prognostic marker. It helps to select patients with increased risk.

In patients with coronary artery disease (CAD), the characteristics of those with discordant exercise thallium 201 single photon emission computed tomography (SPECT) lung uptake (lung-to-heart [L/H] ratio) and left ventricular (LV) transient ischemic dilation (LVTID) are not well defined. The population included 310 patients having exercise Tl-201 SPECT and coronary angiography. The population was subclassified into 4 subgroups: increased L/H ratio only, increased LVTID only, both, and neither. The L/H ratio was weakly correlated to LVTID (r = 0.18). The L/H ratio was correlated to the summed difference score (r = 0.26), summed rest score (r = 0.31), summed stress score (r = 0.5), and rest and stress LV volume (r = 0.5 and r = 0.54, respectively). LVTID was only correlated to the summed difference score (r = 0.32) and stress LV volume (r = 0.17). Increased LVTID only was associated with more frequent ischemia and patients with it tended to be more extensively ischemic, as compared with patients with increased L/H ratio only, but had a similar angiographic extent of CAD. These results were independent of prior myocardial infarction variable. As compared with patients with increased L/H ratio alone, patients with increased LVTID alone are more frequently ischemic but have a similar angiographic extent of CAD. Increased L/H ratio was correlated to both rest and postexercise LV volume, whereas increased LVTID was correlated only to postexercise LV volume.

Transient ischemic dilation (TID) on myocardial perfusion imaging (MPI) has been recognized as specific indicator for multi-vessel coronary artery disease, especially in the setting of concomitant perfusion defects. The clinical significance of TID in an otherwise normal MPI has been a subject of

TID is an abnormal finding in stress myocardial perfusion imaging that suggests severe and extensive CAD and signifies a worse prognosis. TID has been reported with exercise and pharmacologic stress testing, planar and SPECT imaging, and Tl-201, Tc-99m, and dual-isotope protocols. Underlying mechanisms include a combination of stress-induced subendocardial hypoperfusion, ischemic systolic dysfunction, and less likely physical LV dilation with severe ischemia. TID appears to represent a significant ischemic burden and, compared with increased pulmonary Tl-201 uptake, suggests less permanent LV dysfunction and more myocardium at risk. Stress-to-rest LV volume ratios of 1.12 (epicardial) and 1.22 (endocardial) have been consistently shown to be highly specific for severe and extensive CAD.

Introduction: Electrocardiography (ECG)-gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) for the diagnosis and prognosis of coronary artery disease (CAD) is the most commonly performed imaging procedure in nuclear cardiology. Case Presentation: A 67-year-old man underwent exercise electrocardiography (ECG)-gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) for evaluating his mild dyspnea on exertion (New York Heart Association class I). Images showed inducible ischemia of severe intensity in the interior walls and moderate intensity in the apicoseptal and anteroseptal segments, but exercise stress to induce coronary hyperemia revealed marked ST-segment depressions in low heart rates and the patient complained of only mild dyspnea during these ECG changes. He subsequently underwent coronary angiography, which revealed left main and severe three-vessel disease. This discrepancy between the SPECT perfusion images and the extent of coronary artery disease in this case represents the masking of one ischemic territory (left system) by another more severely ischemic territory (right system). Discussion: The reason is that we assess the relative and not absolute differences of the tracer uptake in this imaging modality. There may be other findings on MPI images which could help us overcome this pitfall, including detecting wall motion abnormalities, lung uptake of the tracer, or transient ischemic dilation. Another important issue is the ECG changes during exercise stress testing, which could point to a more extensive coronary artery disease than the one detected on MPI images alone.

1349 eginning with Stolzenberg [1] in 1980 and later popularized by Weiss et al. [2] in 1987, the apparent dilatation of the left ventricular cavity on myocardial perfusion imaging in the presence of extensive epicardial vessel stenoses has been referred to as transient ischemic dilation. Iskandrian et al. [3] provided evidence that the mechanism of this apparent dilatation may involve subendocardial ischemia by revealing increased wall thickness on the delay images when cavity dilatation with myocardial thinning was seen during stress. The severely ischemic, count-poor subendocardium at stress appears as part of the left ventricular cavity with an external rim of slightly better perfused epicardium. The result is a relatively dilated left ventricular cavity during stress imaging. Transient ischemic left ventricular cavity dilatation during stress myocardial perfusion imaging has become a generally accepted marker of severe, Causes of Transient Dilatation of the Left Ventricle During Myocardial Perfusion Imaging Vincent J. B. Robinson 1,2 , James H. Corley 2 , David S. Marks 1,3 , Linton W. Eberhardt 2 , Casimir Eubig 2 , George J. Burke 2 , L. Michael Prisant 1

OBJECTIVESThe purpose of the study was to evaluate the relationship between elevated lung/heart ratio (LHR) and transient ischemic dilation (TID) after stress thallium-201 myocardial perfusion imaging and to provide further insight into the mechanism of cavity dilation.BACKGROUNDBecause both LHR and TID have been identified as adjunctive markers of severe coronary disease they should be found in the same patients. Although the mechanism of LHR has been defined, that of transient dilation has not.METHODSWe identified 4,618 consecutive patients undergoing maximal exercise perfusion imaging with thallium-201. Lung/heart ratio and a dilation index were derived and compared to each other and to relevant clinical parameters.RESULTSThere was a very weak relationship between the LHR and dilation index (r = 0.15, p < 0.001). Defining a dilation index ≥1.10 and LHR ≥50% as abnormal revealed that 322 of the patients (7%) had TID only, 351 (7.8%) had LHR only and 40 (0.9%) had both. When compared to patients without these findings both TID and LHR had higher thallium stress defect and redistribution scores. When comparing subjects who had elevated LHR uptake to those who had TID, it was found that those with LHR were more likely to have had prior myocardial infarction (MI) (29% vs. 9%), coronary artery bypass grafting (22% vs. 8%), lower ejection fraction (34 ± 17% vs. 55 ± 11%) and had more evidence of ischemia based on thallium stress defect and redistribution scores. However, patients with cavity dilation had a higher frequency of positive electrocardiographic response (31% vs. 19%) despite lower scintigraphic markers.CONCLUSIONSAlthough pulmonary uptake and transient cavity dilation have both been associated with severe coronary disease, they have a very weak correlation, which, in combination with the different clinical parameters associated with each, suggests that they represent different pathophysiologic responses to exercise-induced ischemia. Our data support the hypothesis that TID represents transient subendocardial ischemia rather than physical dilation from increased end-diastolic pressure.

Vasodilator first-pass stress cardiac magnetic resonance perfusion imaging [stress cardiac magnetic resonance (CMR)] is a reliable, noninvasive method for evaluating myocardial ischemia; however, it does not routinely evaluate metrics such as wall-motion abnormality (WMA) and transient ischemic dilation (TID). Using the new selective A2A adenosine receptor agonist regadenoson, we tested a novel protocol for assessing perfusion defects, WMA, and TID in a single stress CMR session. We evaluated 29 consecutive patients who presented for clinically indicated regadenoson stress CMR. Immediately before and after the regadenoson stress perfusion sequence, we obtained baseline and post-stress cine images in the short-axis orientation to detect worsening or newly developed WMAs. This approach also allowed evaluation of TID. Delayed-enhancement imaging was performed in the standard orientations. All patients tolerated the procedure well. Thirteen patients (45 %) had perfusion abnormalities, and four patients developed TID. Seven patients had WMAs, and three of them also had TID. Patients with TID ± WMAs had multivessel disease documented by coronary angiography. By using regadenoson to assess myocardial ischemia during stress CMR, perfusion defects, WMAs, and TID can be evaluated in a single imaging session. To our knowledge, we are the first to describe this novel approach in a vasodilator stress CMR study.

Objectives. This study was designed to investigate whether left ventricular ejection fraction (LVEF) calculated from post-stress single-photon emission computed tomography (SPECT) reflects the basal value for LVEF or whether post-stress LVEF is reduced in some patients with stress-induced ischemia.Background. Automated programs are now commercially available for assessing global left ventricular (LV) function from post-stress technetium-99m sestamibi gated SPECT performed >15 min after completion of exercise.Methods. Eighty-one sequential patients who underwent a 2-day stress/rest sestamibi imaging protocol and showed perfusion defects on the post-stress tomogram underwent gated acquisition of the second-day rest tomogram. The post-stress and rest tomographic images were read for presence, location, severity and reversibility of defects by consensus of two to three experienced observers with the aid of circumferential count displays. Defects were scored as mild, moderate or severe and as completely or partially reversible or fixed, and a summed defect severity score was calculated. Of these 81 scans, 20 showed nonreversible perfusion defects (group 3), whereas 61 showed reversible perfusion defects. Post-stress and rest LVEF was calculated from the processed gated SPECT data. From 15 additional patients who underwent rest gated SPECT studies on separate days, serial reproducibility of LVEF values calculated from the gated SPECT data was determined to be ±5.2%. Coronary angiography was performed within 3 months of the scan without intervening events in 47 of 81 patients, including 39 of 61 with reversible perfusion defects.Results. In 22 (36%) of 61 patients with reversible perfusion defects, post-stress LVEF was >5% lower than that at rest (group 2), whereas in the remaining 39 patients, post-stress LVEF was either ±5% or greater than that at rest (group 1). Segmental chordal shortening analysis performed in group 2 studies showed that differences in chordal shortening between rest and post-stress were significantly greater in the reversible perfusion defect territories than in the nonischemic perfusion defect territories ([mean ± SD] 0.14 ± 0.14 vs. 0.02 ± 0.09, respectively, p < 0.0001). There were no significant differences among groups for any of the following variables: age, gender, previous myocardial infarction and type of stress. Time to imaging and stress and scan variables were correlated with the change in LVEF by univariate analysis, and the two variables that correlated significantly were the summed defect reversibility score on the scan and a left anterior descending coronary artery location of the scan defect. Only summed defect reversibility score was significant on multivariate analysis.Conclusions. When the only gated sestamibi scan is the post-stress scan, global and regional LV function will not represent basal LV function in all patients with stress-induced ischemia.

Left ventricular (LV) cavity dilation during stress myocardial perfusion imaging has been associated with multivessel disease, and may be an independent prognostic marker in addition to perfusion defects. The present study examines the predictive value for future cardiac events of transient or fixed LV dilation during dipyridamole technetium-99m (Tc-99m) sestamibi single-photon emission computed tomography (SPECT) imaging. The study included 512 consecutive patients who underwent SPECT imaging with Tc-99m sestamibi after dipyridamole infusion. Transient LV dilation was seen in 70 patients (14%) and 74 had fixed cavity dilation (14%); cavity size was normal in 368 patients (72%). Each perfusion scan was classified as normal or abnormal, and if abnormal, defects were categorized as transient or fixed, and as small, medium, or large (depending upon the number of abnormal vascular territories). Events during a mean follow-up of 12.8 +/- 6.8 months were tabulated by direct review of hospital charts and death certificates. The cardiac event rate (cardiac death or nonfatal infarction) was 1.9% in patients with normal cavity size, 11.4% with transient LV dilation, and 13.5% with fixed LV dilation (p < 0.01). Compared with patients with normal cavity size, those with transient LV dilation were more likely to sustain a myocardial infarction (p < 0.01) and those with fixed dilation more frequently suffered cardiac death (p < 0.01) and hospitalization for heart failure (p < 0.01). The group with the highest risk had both a large perfusion defect and cavity dilation. By Cox proportional hazard regression analysis, both transient and fixed LV dilation were strong independent predictors of cardiac events. Transient or fixed LV dilation are commonly seen during dipyridamole Tc-99m sestamibi SPECT imaging (14% incidence for each) and are useful predictors of cardiac events.

We have developed a software suite that automatically selects, analyses, quantitates and displays all the key image data in a myocardial perfusion SPECT study. Methods: The files automatically selected (upon specification of the patient name) are rest and stress projections, rest and stress short axis and gated short axis files, and all ‘snapshot’ files. The projection data sets are presented in cine mode for evaluation of patient motion, while the lung/heart ratio at rest and stress is calculated from regions of interest (ROIs) that are automatically derived and overlayed on the LAO 45 images. Left ventricular (LV) cavity volumes at rest and stress are calculated from the short axis data sets, and the related transient ischemic dilation (TID) ratio derived and displayed. Quantitative measurements of global (ejection fraction) and regional function parameters are performed from the gated short axis dataset. All algorithms use the C++, X-Windows and OSF-Motif standards. The overall suite executes in less than 1 minute on a SunSPARC5 with 32 Mb of RAM and no proprietary hardware. Results: The software was validated on 144 patients (118 rest201 Tl/post-stress 99mTc-sestamibi, 18 post-stress 99mTc-sestamibi, 8 rest 201Tl) acquired on a 90° dual detector (ADAC Vertex, 91 patients) and a triple detector camera (Picker Prism 3000, 53 patients). Overall, the individual algorithms for the analysis of projection, short axis and gated short axis images were successful in 622/660 (94.2%) of the images. In 80.5% of the patients (73/91+43/53) all algorithms executed successfully, without significant difference in success rates for201 Tl versus 99mTc-sestamibi images. Conclusion: Our automated approach to myocardial perfusion SPECT analysis and review is highly successful, intrinsically reproducible, and can produce time and cost savings while improving accuracy in a clinical or teleradiology-type environment.

Transient ischemic dilation (TID) of the left ventricle during stress myocardial perfusion SPECT (MPS) has been shown to be a useful marker of severe coronary artery disease (CAD). However, investigations in diabetic patients with available coronary angiographic data are still limited. We evaluated the incremental diagnostic value of TID in identifying the presence of angiographically severe CAD in diabetic patients. TID ratio values were automatically derived from rest-stress MPS in 242 diabetic patients with available coronary angiography data. A cutoff of ≥1.19 was considered to represent TID. Severe CAD (≥70% stenosis in the proximal left anterior descending artery or the left main artery, or ≥90% stenosis in two or three vessels) was identified in 69 (29%) patients. At multivariate analysis, the best independent predictors of severe CAD were summed stress score and TID (both P

Transient ischemic dilation (TID) of the left ventricle measured by myocardial perfusion Single Photon Emission Computed Tomography (SPECT) and defined as a the ratio of stress myocardial blood volume to rest myocardial blood volume has been shown to be highly specific for detection of severe coronary artery disease. This work investigates automated quantification of TID from cardiac Computed Tomography (CT) perfusion images. To date, TID has not been computed from CT. Previous studies to compute TID have assumed accurate segmentation of the left ventricle and performed subsequent analysis of volume change mainly on static or less often on gated myocardial perfusion SPECT. This, however, may limit the accuracy of TID due to potential errors from segmentation, perfusion defects or volume measurement from both images. In this study, we propose to use registration methods to determine TID from cardiac CT scans where deformation field within the structure of interest is used to measure the local volume change between stress and rest. Promising results have been demonstrated with 7 datasets, showing the potential of this approach as a comparative method for measuring TID.

Abnormal values of the transient ischemic dilation (TID) ratio are associated with severe and extensive coronary artery disease (CAD). The objective of this study was to determine the relationship between TID, determined from stress and rest ventricular volumes during regadenoson gated single-photon emission computed tomography myocardial perfusion imaging (MPI) dual isotope studies, and the extent of CAD found during coronary angiography. 195 patients who underwent dual isotope MPI with regadenoson and cardiac angiography between March 2009 and February 2010 were analyzed. TID was calculated using commercially available software, Emory Cardiac Toolbox. Mean TID values were compared across disease types. A threshold for abnormal TID was determined by adding two standard deviations (SDs) to the mean TID of the “non-obstructive CAD” subgroup. In the 195-patient group analyzed, the mean TID ratio for non-obstructive CAD (n = 104) was found to be 1.09 with a SD of 0.15. In a subgroup of patients whose angiogram was within 3 months of MPI (n = 155), the mean TIDs for non-obstructive disease (n = 81), single-vessel disease (n = 35), and multi-vessel disease (n = 39) were 1.09, 1.15, and 1.19 with SDs of 0.16, 0.19, and 0.26, respectively. Those with an abnormal TID had a crude and adjusted odds ratio of 3.4 for multi-vessel disease which was statistically significant. History of diabetes was not found to be a significant confounder, effect modifier, or mediator of the relationship between the TID and the vessel disease. The mean TID ratio in patients with multi-vessel disease was 1.19. The threshold for an abnormal TID was 1.39 with specificity of 95% and sensitivity of 15% for determining multi-vessel CAD status. We conclude that the level of TID in gated SPECT MPI using regadenoson is associated with the degree of CAD on angiography.

In hemodialysis (HD) patients, the intravascular volume expansion of the pre-HD state leads to a high preload. We aim to examine its effect on myocardial perfusion gated SPECT (MPGS)-derived left ventricular (LV) volumes. The study comprised 50 end-stage renal disease (ESRD) patients on HD with normal 2-day stress/rest MPGS performed for kidney transplantation risk assessment. Patients (pts) comprised 23 men/27 women, with mean age of 59.4 ± 7.1 years. The time elapsed from the last HD session in hours was calculated on both days, and patients were classified according to whether it was higher (group A: 19 pts), lower (group B: 27 pts), or equal (group C: 4 pts) on the stress vs the rest day. End-diastolic, end-systolic volumes (EDV, ESV), and left ventricular ejection fraction (LVEF) were determined using QGS™ software. Transient ischemic dilation (TID) ratios were derived from the nongated images using QPS™ software. Volumes were significantly higher at stress in group A, at rest in group B, and similar in group C. TID ratios were significantly higher in group A vs groups B and C. MPGS-derived ventricular volumes are preload dependent. The high preload of the pre-HD state may mimic ischemic TID if occurring on the stress day and create confusion if coinciding with the rest day.