The goal of this study was to investigate the added value of absolute MBF quantitation measured with cardiac-dedicated CZT SPECT to enhance the detection of hidden myocardial hypoperfusion for patients with obstructive coronary artery disease and normal perfusion. A total of 501 patients with normal myocardial perfusion imaging (MPI) results who underwent dynamic cardiac-dedicated CZT SPECT for MBF quantitation, routine MPI, and invasive coronary angiography (CAG) were retrospectively identified from the clinical database. Stenosis of > 50

Purpose: XTR003 is a novel 18F-labeled fatty acid PET tracer to image myocardial fatty acid metabolism that can be potentially used to assess myocardial viability for ischemic heart disease. This Phase I study evaluated its safety, biodistribution, radiation dosimetry, and pharmacokinetics. Methods: Ten healthy Chinese volunteers (mean age of 28.4 +/- 4.6 years, 3 females) were intravenously injected with XTR003 (296-370 MBq) at rest and monitored for adverse events on the day of injection and follow-up days. Multiple whole-body PET images were acquired within 290 minutes and processed to investigate the biodistribution and radiation dosimetry. Whole blood, plasma, and urine were collected simultaneously for 420 minutes to evaluate the pharmacokinetics with the measurement of radioactivity. Results: Only two treatment-related adverse events occurred with no severe adverse effects. After tracer injection, XTR003 in the plasma peaked at 2.883 minutes as .0108235% of injected dose per gram (%ID/g) and reduced to the minimum at 30 minutes. The 0-20 minutes whole-body PET images indicated that both heart and liver were two critical organs with the highest percentage of injected dose (%ID) (4.37 +/- .66 and 48.76 +/- 4.17 %ID). Specifically, XTR003 demonstrated high initial uptake in the heart, with sustained retention for up to 290 minutes (standardized uptake value: 6.50 +/- 2.54 at 0-20 minutes and 5.89 +/- 2.18 at 270-290 minutes). The whole-body effective radiation dose was 17 mSv/MBq. The cumulative urinary excretion was 9.009%. Conclusions: XTR003, as an18F-labeled radiotracer, was safe and well-tolerated. The rapid uptake and prolonged retention of XTR003 in the heart show promise for evaluating myocardial fatty acid metabolism. The Phase II clinical trial to explore the efficacy of XTR003 for detecting myocardial viability should be warranted. Trail number: Identifier: NCT05136391.

Objectives: This study assessed the imaging characteristics, pharmacokinetics and safety of XTR004, a novel 18 F-labeled Positron Emission Tomography (PET) myocardial perfusion imaging tracer, after a single injection at rest in humans. Methods: Eleven healthy subjects (eight men and three women) received intravenous XTR004 (239- 290 megabecquerel [MBq]). Safety profiles were monitored on the dosing day and three follow-up visits. Multiple whole-body PET scans were conducted over 4.7 h to evaluate biodistribution and radiation dosimetry. Blood and urine samples collected for 7.25 h were metabolically corrected to characterize pharmacokinetics. Results: In the first 0- 12 min PET images of ten subjects, liver (26.81 +/- 4.01), kidney (11.43 +/- 2.49), lung (6.75 +/- 1.76), myocardium (4.72 +/- 0.67) and spleen (3.1 +/- 0.84) exhibited the highest percentage of the injected dose (%ID). Myocardial uptake of XTR004 in the myocardium initially reached 4.72 %ID and 7.06 g/mL, and negligibly changed within an hour ( D : 7.20%, 5.95%). The metabolically corrected plasma peaked at 2.5 min (0.0013896 %ID/g) and halved at 45.2 min. Whole-body effective dose was 0.0165 millisievert (mSv)/MBq. Cumulative urine excretion was 8.18%. Treatment-related adverse events occurred in seven out of eleven subjects (63.6%), but no severe adverse event was reported. Conclusions: XTR004 demonstrated a favorable safety profile, rapid, high, and stable myocardial uptake and excellent potential for PET myocardial perfusion imaging (MPI). Further exploration of XTR004 PET MPI for detecting myocardial ischemia is warranted.

This study aimed to evaluate image quality, myocardial perfusion, and diagnostic performance of a novel [18F]F-labeled PET tracer, XTR004 PET, myocardial perfusion imaging (MPI) compared with [13N]Ammonia (NH3) PET MPI. Forty-seven patients with suspected or known coronary artery disease (CAD) were prospectively enrolled to undergo one-day rest/ATP-stress XTR004 and NH3 electrocardiograph-gated PET imaging within 2 weeks. Among them, twenty-six patients underwent invasive coronary angiography (ICA), and nineteen were identified with flow-limited CAD (stenosis ≥ 70

Background: It is clinically needed to explore a more efficient imaging protocol for single photon emission computed tomography (SPECT) myocardial blood flow (MBF) quantitation derived from cadmium zinc telluride (CZT) SPECT camera for the routine clinical utilization. Methods: One hundred and twenty patients with matched clinical characteristics and angiographic findings who completed one-day rest/stress SPECT imaging with either the intermittently sequential imaging (ISI) protocol (two dynamic and two electrocardiography (ECG)-gated scans) or the continuous rapid imaging (CRI) protocol (two dynamic/ECG-gated scans) were included. MBF quantitation adopted residual activity correction (RAC) to correct for rest residual activity (RRA) in the stress dynamic SPECT scan for the detection of flow-limited coronary artery disease. Results: The CRI protocol reduced about 6.2 times shorter than the ISI protocol (25.5 min vs 157.6 min), but slightly higher than the RRA (26.7% +/- 3.6% vs 22.3% +/- 4.9%). With RAC, both protocols demonstrated close stress MBF (2.18 +/- 1.13 vs 2.05 +/- 1.10, P > 0.05) and myocardial flow reserve (MFR) (2.42 +/- 1.05 vs 2.48 +/- 1.11, P > 0.05) to deliver comparable diagnostic performance (sensitivity = 82.1%- 92.3%, specificity = 81.2%- 91.2%). Myocardial perfusion and left ventricular function overall showed no significant difference (all P > 0.26). Conclusion: One-day rest/stress SPECT with the CRI protocol and rest RAC is feasible to warrant the diagnostic performance of MBF quantitation with a shortened examination time and enhanced patient comfort. Further evaluation on the impact of extracardiac activity to regional MBF and perfusion pattern is required. Additional evaluation is needed in a patient population that is typical of those referred for SPECT MPI, including those with known or suspected coronary microvascular disease.

Purpose CZT SPECT with the enhanced imaging characteristic facilitates SPECT myocardial blood flow (MBF) quantitation moving toward a clinical utility to uncover myocardial ischemia. The purpose of this study was to investigate the diagnostic performance of stress MBF, myocardial flow reserve (MFR) and myocardial flow capacity (MFC) derived from CZT SPECT in the detection of coronary artery disease (CAD). Methods One-hundred and eighty patients underwent two-day rest/adenosine-stress scans for SPECT MBF quantitation. All dynamic SPECT images were reconstructed and corrected with necessary corrections. The one-tissue two-compartment kinetic model was utilized to fit kinetic parameters (K1, k2 and FBV) by numeric optimization and converted to MBF from K1. Rest MBF, stress MBF and MFR in left ventricle and coronary territories were calculated from flow polar maps. MFC was assessed by extents of moderately and severely abnormal flow statuses using an integrated flow diagram. Per-patient and per-vessel analyses were performed to determine cutoff values for the detection of angiographically obstructive and flow-limited CAD. Results Using the threshold of ≥ 50% stenosis, 149 patients (82.78%) were classified to have obstructive lesions in 355 vessels (65.74%). Using the threshold of ≥ 70% stenosis, 113 patients (62.78%) were classified to have flow-limited lesions in 282 vessels (52.22%). On per-patient analysis, the optimal cutoff values of stress MBF and MFR to detect ≥ 50% stenosis were (1.44 ml/min/g, 1.96) and (1.34 ml/min/g and 1.75) to detect ≥ 70% stenosis. The optimal cutoff values for severely and combined moderately severely abnormal MFC extents were (2.3-2.5%, 23.1%) and (7.5%, 29.4%), respectively. The overall sensitivity of MFC (0.84-0.86, 0.86-0.90) to detect ≥ 50% and ≥ 70% lesions surpassed those of stress MBF (0.78. 0.78) and MFR (0.80, 0.75) (all p < 0.05) with similar specificity (MFC = 0.84-0.90, 0.87-0.91; stress MBF = 0.87, 0.91; MFR = 0.84, 0.89) (all p ≥ 0.05). Conclusion The non-invasive SPECT MBF quantitation using CZT SPECT is a reliable method to detect angiographically obstructive and flow-limited CAD. Myocardial flow capacity can outperform with higher diagnostic sensitivity than stress MBF or MFR alone.

The aim of this prospective multi-center study was to investigate the diagnostic value of myocardial blood flow (MBF) quantification using NaI(Tl)-based single-photon emission computed tomography (SPECT) for determining coronary artery disease (CAD) defined by quantitative coronary angiography (QCA). Absolute quantitation of MBF and myocardial flow reserve (MFR) using SPECT is clinically feasible; however, whether flow quantification using NaI(Tl) SPECT is superior to commonly performed SPECT myocardial perfusion imaging (MPI) in determining CAD has not been evaluated. Patients with suspected or known CAD underwent pharmacological stress/rest dynamic SPECT imaging and routine SPECT MPI followed by QCA. Obstructive disease was defined as ≥ 50% reduction in luminal diameter on QCA. One hundred fifty-four patients (462 vessels) were included in the analysis. Obstructive CAD was detected in 76/154 patients (49.4%) and 112/462 vessels (24.2%). Optimal cut-off values were 1.86 mL/min/g for stress MBF and 1.95 for MFR, respectively. Stress MBF and MFR were more sensitive than MPI in both individual patients (stress MBF vs MPI: 81.6% vs 51.3%; MFR vs MPI: 72.4% vs 51.3%) and in coronary vascular regions (stress MBF vs MPI: 78.6% vs 31.3%; MFR vs MPI: 75.9% vs 31.3%; all P < .01). In receiver operating characteristic curve analysis, quantification revealed a significantly greater area under the curve than MPI at the patient (stress MBF vs MPI: 0.761 vs 0.641; MFR vs MPI: 0.770 vs 0.641) and the vessel (stress MBF vs MPI: 0.745 vs 0.613; MFR vs MPI: 0.756 vs 0.613; all P < .05) levels. Integrating quantitative SPECT measures with MPI significantly increased the area under the curve and improved the discriminatory and reclassification capacity. Flow quantification using NaI(Tl) SPECT provides superior sensitivity and discriminatory capacity to MPI in detecting significant stenosis. Clinical trial registration NCT03637725.

HomeCirculation: Cardiovascular ImagingVol. 15, No. 3Serial Changes of 99mTc-Sestamibi Washout Due to Coronary Spasm Captured by Dynamic Myocardial Perfusion Imaging With Cardiac Dedicated CZT-SPECT: a Case Report Free AccessCase ReportPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessCase ReportPDF/EPUBSerial Changes of 99mTc-Sestamibi Washout Due to Coronary Spasm Captured by Dynamic Myocardial Perfusion Imaging With Cardiac Dedicated CZT-SPECT: a Case Report Yue Chen, MD, MS, Ze-kun Pang, MD, MS, Jiao Wang, MD, PhD, Rui-fei Yang, MD, MS, Rui Jing, MD, MS, Hong-xin Chu, MD, MS, Bailing Hsu, PhD, Wen-hua Lin, MD, MS and Jian-ming Li, MD, PhD Yue ChenYue Chen Department of Nuclear Medicine (Y.C., Z.-k.P., J.W., H.-x.C., J.-m.L.), TEDA International Cardiovascular Hospital, China. , Ze-kun PangZe-kun Pang Department of Nuclear Medicine (Y.C., Z.-k.P., J.W., H.-x.C., J.-m.L.), TEDA International Cardiovascular Hospital, China. , Jiao WangJiao Wang Department of Nuclear Medicine (Y.C., Z.-k.P., J.W., H.-x.C., J.-m.L.), TEDA International Cardiovascular Hospital, China. , Rui-fei YangRui-fei Yang Department of Cardiology (W.h.L; R.-f.Y., R.J.,.), TEDA International Cardiovascular Hospital, China. , Rui JingRui Jing Department of Cardiology (W.h.L; R.-f.Y., R.J.,.), TEDA International Cardiovascular Hospital, China. , Hong-xin ChuHong-xin Chu Department of Nuclear Medicine (Y.C., Z.-k.P., J.W., H.-x.C., J.-m.L.), TEDA International Cardiovascular Hospital, China. , Bailing HsuBailing Hsu Correspondence to: Jian-ming Li, MD, PhD, Department of Nuclear Medicine, TEDA International Cardiovascular Hospital, Tianjin 300457, China, Email E-mail Address: [email protected] or Wen-hua Lin, MD, MS, Department of Cardiology, TEDA International Cardiovascular Hospital, Tianjin 300457, China, Email E-mail Address: [email protected] or Bailing Hsu, PhD, Nuclear Science and Engineering Institute, University of Missouri-Columbia, E2433 Lafferre Hall, University of Missouri-Columbia, Columbia, MO 65211, Email E-mail Address: [email protected] Nuclear Science and Engineering Institute, University of Missouri-Columbia (B.H.). , Wen-hua LinWen-hua Lin Department of Cardiology (W.h.L; R.-f.Y., R.J.,.), TEDA International Cardiovascular Hospital, China. and Jian-ming LiJian-ming Li https://orcid.org/0000-0002-2585-4753 Department of Nuclear Medicine (Y.C., Z.-k.P., J.W., H.-x.C., J.-m.L.), TEDA International Cardiovascular Hospital, China. Originally published23 Feb 2022https://doi.org/10.1161/CIRCIMAGING.121.013687Circulation: Cardiovascular Imaging. 2022;15Other version(s) of this articleYou are viewing the most recent version of this article. Previous versions: February 23, 2022: Ahead of Print A 64-year-old man with a history of smoking and known coronary artery disease underwent percutaneous coronary intervention in left anterior descending artery 4 years ago. Recently, he was admitted to hospital after experiencing intermittent retrosternal pain for 3 days. A blood test for biochemical indices came back negative. His electrocardiography showed T-wave changes, and his echocardiogram showed a normal left ventricular ejection fraction, 63%. The patient was further instructed to undergo dynamic myocardial perfusion imaging (MPI) on a cardiac single photon emission computed tomography (SPECT) using cadmium zinc telluride detector scanner to measure myocardial blood flow over a one-day period. As part of the dynamic SPECT imaging protocol, a rest scan was performed immediately before the first intravenous injection of 99mTc-sesetami (MIBI) tracer, and an hour later, a stress scan was conducted 3 minutes following the intravenous infusion of adenosine (0.14 mg/kg per minute) and immediately before the second MIBI injection. Serial ECGs were recorded during the stressing process to monitor patient safety. The patient complained of chest pain and shortness of breath throughout the adenosine infusion and developed coronary spasms (CS) 2.5 minutes after the infusion. His SPECT myocardial blood flow quantitation showed an abnormally low myocardial flow reserve of 1.39, in combination with an abnormal myocardial flow capacity of 38.19% extent of moderately and severely anomalous flow statues, an indication of myocardial ischemia (Figure 1). Additionally, stress dynamic MPI data further divided into sequences of perfusion images revealed MIBI washout gradually in the inferoseptal, inferior and apical myocardium, which ultimately led to large stress perfusion defects in regions (from 0% to 31%) and diminished left ventricular ejection fraction (from 64% to 48%; Figure 2). Serial electrocardiograms showed progressive development of CS and remission after treatment with high-concentrated oxygen and sublingual nitroglycerin (Figure 3). Figure 4 shows the time sequence from the peak stress stage to the end of the stress dynamic SPECT scan. He was transferred to receive an urgent coronary angiography, which revealed only mild hyperplasia in the previously implanted stent in the proximal left anterior descending and 99% spastic occlusion in the middle left anterior descending. Following the infusion of 200 μg of nitroglycerin through the catheter, the spasm was controlled, and no residual abnormality in the coronary intima was observed on coronary angiography and confirmed by optical coherence tomography (Figure 5).Download figureDownload PowerPointFigure 1. Single photon emission computed tomography myocardial blood flow (MBF) quantitation from dynamic myocardial perfusion imaging. LAD indicates left anterior descending; LCX, left circumflex; LV, left ventricle; MFR, myocardial flow reserve; and RCA, right coronary artery.Download figureDownload PowerPointFigure 2. Serial change of 99mTc-Sestamibi washout and diminished left ventricular ejection fraction (LVEF) starting from the completion of adenosine infusion. LAD indicates left anterior descending; LCX, left circumflex; and RCA, right coronary artery.Download figureDownload PowerPointFigure 3. Real-time ECG monitoring during the adenosine-stress dynamic single photon emission computed tomography acquisition. A, Baseline ECG at rest stage. B, Peak-stress ECG at 3 min post the adenosine infusion. C, ECG in the early stage of spasm showing obvious ST-segmental and T-wave elevation in the anterior wall leads at 2.5 min post the end of adenosine infusion. D, ECG in the peak of spasm showing ST-segmental elevation in multiple leads, ST-segmental elevation above R waves in the anterior wall leads (V2, V3, and V4), and T-wave fusion with tombstone-like change at 4.3 min. E, Progressive ECG showing short bursts of VA during the peak of spasm at 5.1 min. F, The frequency of short bursts of VA became slower during the control period of spasm after sublingual 0.5 mg nitroglycerin at 7 min. G, Early remission of spasm showed a tendency of ST-segmental regression in the anterior wall leads at 7.5 and 7.75 min. VA indicates ventricle and atrium.Download figureDownload PowerPointFigure 4. The time sequence of coronary spasm event from the peak stress stage (3 min post the adenosine infusion) to the end of stress dynamic single photon emission computed tomography scan. LVEF indicates left ventricular ejection fraction; MIBI, 99mTc-sesetami; MPI, myocardial perfusion imaging; NTG, nitroglycerin; and VA, ventricle and atrium.Download figureDownload PowerPointFigure 5. Coronary angiography of coronary spasm observed before and after intracoronary nitroglycerin treatment, and the transparent intima reconfirmed by optical coherence tomography (OCT). LAD indicates left anterior descending; LCX, left circumflex; NTG, nitroglycerin; and RCA, right coronary artery.CS is a transient constriction of the coronary artery that may lead to myocardial ischemia downstream as a result of partial or complete occlusion. Clinically, this event cannot be measured in real-time without an intracoronary provoking procedure (eg, Ergometrine test). Nonetheless, some previous studies have observed MIBI washout in the myocardium caused by CS in delayed SPECT imaging.1 The present study, to our knowledge, is the first to report the kinetic of myocardial MIBI washout induced by CS during the adenosine-stress dynamic SPECT scan. According to this patient's dynamic perfusion and ECG, MIBI washout was instantaneous when acute myocardial ischemia occurred. MIBI washout is explained by local Ca+2 accumulation causing depolarization in the transmembrane of mitochondria, resulting in the loss of MIBI cation to be indicative of mitochondrial dysfunction.From our study, 3 points can be learned as follows:The progressive development of myocardial ischemia leading to mitochondrial dysfunction can be very rapid during severe CS episodes. It is vital to seek immediate medical treatment at the onset of CS to prevent further acute injury to myocytes.Provocative tests with acetylcholine or ergometrine have been proposed to diagnose CS, but their safety remains a major concern.2 Adenosine as a vessel dilatator has been widely used in MPI with a well-accepted safety profile, and cases of CS following an adenosine-stress test have been reported.3 The results of this study demonstrate that dynamic MPI with adenosine is an effective method to monitor CS progression and reflect the pathophysiological characteristic by measuring the MIBI washout kinetics.CS often coexists with coronary microvascular dysfunction, as this patient population has a strikingly increased risk of cardiac events.4 In this case, myocardial flow reserve and myocardial flow capacity in 3 vessel territories were overall abnormal to additionally indicate diffuse coronary microvascular dysfunction. SPECT myocardial blood flow quantitation is, therefore, valuable for assessing the coexistence of CS and coronary microvascular dysfunction.In conclusion, serial changes in MIBI washout in dynamic MPI with cardiac dedicated SPECT using cadmium zinc telluride detector can be useful to evaluate the mitochondrial dysfunction and the severity of myocardial ischemia when CS occurs. Further quantification of myocardial blood flow reveals clinical insight on whether CS and coronary microvascular dysfunction coexist.Article InformationSources of FundingNone.Disclosures None.FootnotesFor Sources of Funding and Disclosures, see page 186.Correspondence to: Jian-ming Li, MD, PhD, Department of Nuclear Medicine, TEDA International Cardiovascular Hospital, Tianjin 300457, China, Email [email protected]com or Wen-hua Lin, MD, MS, Department of Cardiology, TEDA International Cardiovascular Hospital, Tianjin 300457, China, Email [email protected]com or Bailing Hsu, PhD, Nuclear Science and Engineering Institute, University of Missouri-Columbia, E2433 Lafferre Hall, University of Missouri-Columbia, Columbia, MO 65211, Email [email protected]comReferences1. Ono S, Takeishi Y, Yamaguchi H, Abe S, Tachibana H, Sato T, Kubota I. Enhanced regional washout of technetium-99m-sestamibi in patients with coronary spastic angina.Ann Nucl Med. 2003; 17:393–398. doi: 10.1007/BF03006607CrossrefMedlineGoogle Scholar2. Kaski JC. Testing for coronary artery spasm noninvasively: potentially ideal, but safe?JACC Cardiovasc Imaging. 2020; 13:1888–1890. doi: 10.1016/j.jcmg.2020.04.002CrossrefMedlineGoogle Scholar3. Han PP, Tian YQ, Wei HX, Wang Q, He ZX. Coronary spasm after completion of adenosine pharmacologic stress test.Ann Nucl Med. 2011; 25:580–585. doi: 10.1007/s12149-011-0493-zCrossrefMedlineGoogle Scholar4. Suda A, Takahashi J, Hao K, Kikuchi Y, Shindo T, Ikeda S, Sato K, Sugisawa J, Matsumoto Y, Miyata S, et al. Coronary functional abnormalities in patients with angina and nonobstructive coronary artery disease.J Am Coll Cardiol. 2019; 74:2350–2360. doi: 10.1016/j.jacc.2019.08.1056CrossrefMedlineGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetails March 2022Vol 15, Issue 3 Advertisement Article InformationMetrics © 2022 American Heart Association, Inc.https://doi.org/10.1161/CIRCIMAGING.121.013687PMID: 35290080 Originally publishedFebruary 23, 2022 Keywordsmyocardial perfusion imagingnitroglycerincoronary angiographyelectrocardiographyspasmPDF download Advertisement SubjectsCoronary Artery DiseaseNuclear Cardiology and PET

Background 99m Tc-PYP scintigraphy provides differential diagnosis of ATTR cardiomyopathy (ATTR-CM) from light chain cardiac amyloidosis and other myocardial disorders without biopsy. This study was aimed to assess the diagnostic feasibility and the operator reproducibility of 99m Tc-PYP quantitative SPECT. Method Thirty-seven consecutive patients who underwent a 99m Tc-PYP thorax planar scan followed by SPECT and CT scans to diagnose suspected ATTR-CM were enrolled. For the quantitative SPECT, phantom studies were initially performed to determine the image conversion factor (ICF) and partial volume correction (PVC) factor to recover 99m Tc-PYP activity concentration in the myocardium for calculating the standardized uptake value (SUV) (unit: g/ml). SUV max was compared among groups of ATTR-CM, AL cardiac amyloidosis, and other pathogens (others) and among categories of Perugini visual scores (grades 0–3). The intra- and inter-operator reproducibility of quantitative SPECT was verified, and the corresponded repeatability coefficient (RPC) was calculated. Results The ICF was 79,327 Bq/ml to convert count rate in pixel to 99m Tc activity concentration. PVC factor as a function of the measured activity concentration ratio in the myocardium and blood-pool was [ y = 1.424 × (1 − exp(− 0.759 × x )) + 0.104]. SUV max of ATTR-CM (7.50 ± 2.68) was significantly higher than those of AL (1.96 ± 0.35) and others (2.00 ± 0.74) (all p < 0.05). SUV max of grade 3 (8.95 ± 1.89) and grade 2 (4.71 ± 0.23) were also significantly higher than those of grade 1 (1.92 ± 0.31) and grade 0 (1.59 ± 0.39) (all p < 0.05). Correlation coefficient ( R 2 ) of SUV max reached 0.966 to 0.978 with only small systematic difference (intra = − 0.14; inter = − 0.23) between two repeated measurements. Intra- and inter-operator RPCs were 0.688 and 0.877. Conclusions 99m Tc-PYP quantitative SPECT integrated with adjustable PVC factors is feasible to quantitatively and objectively assess the burden of cardiac amyloidosis for diagnosis of ATTR-CM.

We aimed to evaluate the feasibility of resting myocardial blood flow (rMBF), quantified with dynamic 13 N-Ammonia (NH3) PET, for identifying myocardial viability and predicting improvement of left ventricular ejection fraction (LVEF) after coronary artery bypass grafting (CABG). Ninety-three patients with coronary artery disease (CAD) and chronic LVEF < 45%, scheduled for CABG, had dynamic 13NH3 PET and 18F-FDG PET imaging. The perfusion/metabolism polar maps were categorized in four patterns: normal (N), mismatch (M1), match (M2) and reverse mismatch (RM). The value of rMBF for identifying viable myocardium (M1, RM) and post CABG improvement of LVEF≥8% was analyzed by receiver operating characteristic (ROC) curves. Correlations of rMBF in segments to ΔLVEF post CABG were verified. Mean rMBFs were significantly different (N=0.60±0.14; M1=0.44±0.07, M2=0.34±0.08, RM=0.53±0.09 ml/min/g, P<0.001). The optimal rMBF cutoff to identify viable myocardium was 0.42 ml/min/g (sensitivity=88.3%, specificity=82.0%) and 0.43 ml/min/g for predicting improvement of LVEF ≥8% (74.6%, 80.0%). The extent and rMBF of combined M1/RM demonstrated a moderate to high correlation to improved LVEF (r=0.78, 0.71, P<0.001). Resting MBF, derived by dynamic 13NH3 PET, may be positioned as a supplement to 18F-FDG PET imaging for assessing the presence of viable myocardium and predicting potential improvement of LVEF after CABG.

Short imaging protocol to quantify myocardial blood flow (MBF) and myocardial flow reserve (MFR) may enhance the clinical application of 13N-ammonia cardiac PET. We assessed the flow quantitation of 13N-ammonia PET implementing simple retention model and two-compartment model.

The purpose of this study was to evaluate subjects with high-risk alcohol cardiotoxicity and patients with alcoholic cardiomyopathy (ACM) via dynamic 11C-Acetate positron emission tomography (PET) imaging as a myocardial oxidative metabolic probe. We recruited 37 subjects with chronic alcohol consumption [18 with moderate consumption (MC), 19 with heavy consumption (HC)], 5 ACM patients, and 12 healthy controls to receive dynamic 11C-Acetate PET scans. PET imaging data were analyzed to calculate kinetic parameters (e.g., Kmono, K1 and k2) based on the mono-exponential and one-tissue compartmental models. Myocardial oxygen consumption (MVO2) and myocardial external efficiency (MEE) were then derived from these kinetic parameters. MVO2 was significantly lowered in the HC group and in ACM patients (0.121± 0.018 and 0.111 ± 0.017 mL·g−1·min−1, respectively) compared with those in healthy controls and MC subjects (0.144 ± 0.023 and 0.146 ± 0.027 mL·g−1·min−1, respectively; P < .01). MEE was significantly reduced in ACM patients (13.0% ± 4.3%) compared with those of healthy controls (22.4% ± 4.6%, P < .01), MC subjects (20.1% ± 4.5%, P < .05), and HC subjects (22.3% ± 4.5%, P < .001). Functional assessment via dynamic 11C-Acetate PET imaging may represent a clinically feasible probe for identifying cohorts with high-risk cardiotoxicity due to addictive alcohol consumption and ACM.

99mTc-3SPboroxime is a 99mTc(III) complex with high initial heart uptake comparable to that of 99mTc-Teboroxime, but with significantly longer myocardial retention in Sprague–Dawley rats. This study was performed to demonstrate its feasibility on myocardial perfusion imaging and myocardial blood flow quantification in swine models. Dynamic single-photon emission computed tomography (SPECT) studies with 99mTc-3SPboroxime were performed in normal (with/without dipyridamole, n = 9) and acute myocardial infarction (AMI) swine (n = 3) in comparison with 99mTc-Teboroxime and 99mTc-Sestamibi. List-mode acquisitions were immediately started after injection and continued for 15 minutes. Regions of interest were drawn on heart (infarct and remote areas of AMI swine) and liver to generate time activity curves. Heart/liver and infarct/remote radioactivity ratios were calculated. One-tissue compartment model was implemented to obtain K1 and K2 values. The initial heart uptake of 99mTc-3SPboroxime was close to that of 99mTc-Teboroxime, but higher than that of 99mTc-Sestamibi. 99mTc-3SPboroxime had a myocardial retention longer than that of 99mTc-Teboroxime. The heart/liver ratio of 99mTc-3SPboroxime was higher than that of 99mTc-Teboroxime at later stage (13-15 minutes post-injection). The K1 value of 99mTc-3SPboroxime was much higher than that of 99mTc-Sestamibi, and the K2 value was significantly lower than that of 99mTc-Teboroxime both at rest and dipyridamole stress (rest K1: 0.63 ± 0.11 vs 0.40 ± 0.04 mL·min−1·g−1, P = 0.027; stress K1: 0.89 ± 0.05 vs 0.54 ± 0.08 mL·min−1·g−1, P = 0.031; rest K2: 0.22 ± 0.04 vs 0.33 ± 0.11 mL·min−1·g−1, P = 0.003; stress K2: 0.31 ± 0.03 vs 0.60 ± 0.30 mL·min−1·g−1, P = 0.047). High quality SPECT images could be obtained in any of the 5 minutes windows over the first 15 minutes after injection of 99mTc-3SPboroxime in normal and AMI swine models. Apical and anterior perfusion defects were clearly visualized in AMI swine. 99mTc-3SPboroxime is a promising radiotracer for future clinical translation considering its heart uptake, heart/liver ratio and SPECT image quality, as well as the advantage over 99mTc-Sestamibi in the definition of stress flow.