Ventricular Perfusion Defects Research Articles

Metabolic Changes Precede Radiation-Induced Cardiac Remodeling in Beagles: Using Noninvasive 18F-FDG (18F-Fludeoxyglucose) and 13N-Ammonia Positron Emission Tomography/Computed Tomography Scans.

BackgroundThis study was performed to characterize the metabolic, functional, and structural cardiac changes in a canine model of radiation‐induced heart disease by serial in vivo imaging and ex vivo analyses.Methods and ResultsThirty‐six dogs were randomly assigned to control or irradiated groups at 3 time points (months 3, 6, and 12 after radiation; each group comprised 6 dogs). The left anterior myocardium of dogs in irradiated groups was irradiated locally with a single dose of 20‐Gy X‐ray. The irradiated myocardial regions showed increased myocardial uptake of 18F‐FDG (18F‐fludeoxyglucose) in the irradiated beagles, but the increased uptake area decreased at months 6 and 12 compared with month 3 after radiation. Abnormality of myocardial perfusion and cardiac function were detected at month 6 after radiation. Compared with the control groups, the protein expression of GLUT4 (glucose transporter 4) was upregulated in the irradiated groups, correlating with significantly decreased CPT1 (carnitine acyltransferase 1) expression. Mitochondria degeneration, swelling, and count reduction in the irradiated groups were observed. The difference in CD68 of macrophage markers and the inflammatory cytokines (IL‐6 [interleukin 6], TNF‐α [tumor necrosis factor α]) between the irradiation and control groups was not significant. Furthermore, the progressive aggravation of apoptosis and fibrosis was displayed.ConclusionsElevated 18F‐FDG uptake occurred after irradiation and subsequently led to ventricular perfusion defects and dysfunction. The process was associated with myocardial metabolic substrate remodeling, cardiac muscle cell apoptosis, and myocardial fibrosis rather than inflammation.

P3716Risk stratification among diabetic patients undergoing stress myocardial perfusion imaging and the relation with systolic ventricular function and perfusion defects

P3716Risk stratification among diabetic patients undergoing stress myocardial perfusion imaging and the relation with systolic ventricular function and perfusion defects

CARDIAC TROPONIN T CONCENTRATIONS MEASURED WITH A HIGH-SENSITIVITY ASSAY AND REVERSIBLE MYOCARDIAL ISCHEMIA IN PATIENTS WITH SUSPECTED STABLE ANGINA: A DOPPLER-CIP SUBSTUDY

Cardiac troponin T measured with high sensitivity assays (hs-cTnT) have been associated with reversible myocardial ischemia, but whether hs-cTnT concentrations are related to the presence of reversible ventricular hypokinesia or perfusion defects in patients with suspected stable angina is unknown

Association between left ventricular perfusion defects and myocardial deformation indexes in heart transplantation recipients

The aim of the study was to analyze possible correlations between strain echocardiography (STE) and PET myocardial perfusion in a population of heart transplantation (HTx) recipients showing preserved left ventricular (LV) ejection fraction. By STE, LV global longitudinal strain (LV GLS) was lower in HTx. PET showed no transient or chronic ischemia in 83 of 115 HTx (73%). Fixed perfusion defects were observed in 17% of HTx and reversible ischemia in 10%. Significant coronary stenosis was observed only in 10 cases. GLS was independently associated with age at HTx and fixed perfusion defects (HR 0.41; P<.001). Such relationships underline STE ability to early identify HTx pts with subclinical myocardial dysfunction during long-term follow-up.

Regadenoson provides perfusion results comparable to adenosine in heterogeneous patient populations: A quantitative analysis from the ADVANCE MPI trials

BackgroundTotal and reversible left ventricular (LV) perfusion defect size (PDS) predict patient outcome. Limited data exist as to whether regadenoson induces similar perfusion abnormalities as observed with adenosine. We sought to determine whether regadenoson induces a similar LV PDS as seen with adenosine across varying patient populations. Methods and ResultsADVANCE MPI were prospective, double-blind randomized trials comparing regadenoson to standard adenosine myocardial perfusion tomography (SPECT). Following an initial adenosine SPECT, patients were randomized to either regadenoson (N = 1284) or a second adenosine study (N = 660). SPECT quantification was performed blinded to randomization and image sequence. Propensity analysis was used to define comparability of regadenoson and adenosine perfusion results. Baseline clinical and SPECT results were similar in the two randomized groups. There was a close correlation between adenosine and regadenoson-induced total (r2 = 0.98, P < .001) and reversible (r2 = 0.92, P < .001) PDS. Serial differences in total (0.00 ± 3.51 vs −0.11 ± 3.46, P = .51) and reversible (0.15 ± 3.79 vs 0.07 ± 3.33, P = .65) PDS were also comparable in patients randomized to regadenoson vs adenosine, respectively, and irrespective of age, gender, diabetic status, body mass index, or prior cardiovascular history. By propensity analysis, regadenoson-induced total PDS was significantly larger than observed with adenosine. ConclusionThis is the first study to show that regadenoson induces similar, if not larger, perfusion defects than those observed with adenosine across different patient populations and demonstrates the value of quantitative analysis for defining serial changes in SPECT perfusion results. Regadenoson should provide comparable diagnostic and prognostic SPECT information to that obtained with adenosine.

Right ventricular stress-induced perfusion defects and late gadolinium enhancement in coronary artery disease.

The assessment of right ventricular (RV) perfusion defects has remained challenging during vasodilator stress perfusion with cardiovascular magnetic resonance (CMR). The significance of RV signal abnormalities during vasodilator stress perfusion and late gadolinium-enhanced CMR is yet uncertain. Among 61 individuals who underwent adenosine CMR stress testing before cardiac catheterization, we assessed the severity of coronary artery stenoses, mortality, the presence of stress and rest perfusion defects, as well as the presence of late gadolinium enhancement (LGE). Right ventricular stress-induced perfusion defects were positively associated with left anterior descending artery and proximal right coronary artery stenoses but were negatively associated with left circumflex artery stenoses. The presence of RVLGE was associated with mortality, but 77% of those with RVLGE also had left ventricular LGE. Proximal right coronary artery and left anterior descending artery stenoses are positively associated, whereas left circumflex artery stenoses are negatively associated with RV stress-induced perfusion defects. Right ventricular LGE was associated with mortality, but further study is needed to determine whether this is independent of left ventricular LGE.

Right ventricular stress-induced perfusion defects and late gadolinium enhancement in coronary artery disease

Right ventricular stress-induced perfusion defects and late gadolinium enhancement in coronary artery disease

Small, Short-Duration, Dobutamine-Induced Perfusion Defects Are Not Associated With Adverse Prognosis in Intermediate-Risk Individuals Receiving Cardiovascular Magnetic Resonance Stress Imaging

The objective of this study was to assess the frequency and prognostic utility of small, short-duration left ventricular myocardial perfusion defects during dobutamine cardiovascular magnetic resonance (DCMR) stress imaging. We performed first-pass contrast-enhanced DCMR at peak stress in 331 consecutively recruited individuals (aged 68 ± 8 years, 50% men) at intermediate risk for a future cardiac event. Size, location, and persistence of low-signal intensity perfusion defects were recorded. Cardiac events were assessed by personnel blinded to imaging results for a median of 24 months after the DCMR. Among the 55 individuals (16.6%) who exhibited small (<25% myocardial thickness) and short-duration (<5 frames in persistence) perfusion defects, diabetes was more prevalent (P = 0.019) and no cardiac events were observed. Large, persistent perfusion defects were associated with coronary artery disease, prior myocardial infarction, and decreased left ventricular function (P < 0.001 for all) and increased 2-year risk for a cardiac event (hazard ratio, 10.3; P < 0.001; confidence interval, 3.3-33.0). In individuals with diabetes, hypertension, or coronary artery disease at intermediate risk for a future cardiac event, small, short-duration DCMR perfusion defects are not associated with increased 2-year risk for a subsequent cardiac event.

Assessing risk in acute chest pain: The value of stress myocardial perfusion imaging in patients admitted through the emergency department

To prospectively assess the clinical value of stress-gated myocardial single photon emission computed tomography (SPECT) for triaging patients admitted through the emergency department (ED) with acute chest pain (ACP). Prospective, observational cohort study in 1,576 consecutive patients who were evaluated for ACP over a 29-month period. Stress SPECT was performed within 24 hours of admission from the ED. Analysis included quantification of total and ischemic left ventricular perfusion defect size (PDS). Cardiac events were defined as an acute coronary syndrome during the index hospitalization or in follow-up over 7.3 ± 2.8 months. Eighty-five cardiac events occurred in 77 patients (4.9%). SPECT was abnormal in 135 patients (8.6%) of whom 83 (61.5%) had a reversible defect. Event rates were significantly higher in patients with an abnormal (40%) versus a normal (1.6%) SPECT (P < .0001); and in those with a (1) large (>15%) versus small (≤15%) PDS (50.0% vs 33.7%, P = .05) and (2) large (>10%) versus small (≤10%) ischemic PDS (87.5% vs 42.4%, P < .0001, respectively). SPECT best predicted cardiac events by multivariate analysis. The addition of SPECT to clinical variables significantly improved overall risk prediction (global χ(2) 103.6 vs 207.1, P < .001). Stress SPECT can accurately assess risk in a heterogeneous group of patients with ACP of unclear cardiac etiology, and beyond that provided by a clinical risk assessment alone. Our results support the use of stress SPECT for identifying very low-risk ACP patients with normal study results who can be safely discharged home.

Quantitative Comparison of Myocardial Perfusion Defects using Different Reconstruction Algorithms

Objective: To investigate the impact of a reconstruction method incorporating corrections for scatter, attenuation, and distance dependent detector response on cardiac single emission computed tomography (SPECT) perfusion studies compared with filtered back projection (FBP). Materials and methods: A total of 20 patients underwent same-day, rest-stress SPECT/CT myocardial perfusion imaging. Images were reconstructed using iterative 3D ordered-subsets expectation-maximization (OSEM 3D) and FBP algorithms. Stress and rest myocardial perfusion defects were quantified using polar maps and normal database comparisons. The Bland-Altman plots were used to assess their degree of agreement. Results were confirmed by coronary angiography. The contrast, contrast to noise ratio and signal to noise ratio were used for the quantitative evaluation of the reconstruction quality. Results: Perfusion defect extent quantification on OSEM 3D reconstructed images agreed and correlated well with defect extent quantification on FBP reconstructed images (bias ± standard deviation, -15% ± 20; r = 0.63) during stress and at rest (-10% ±15; r=0.70). Agreement and correlation were similar for severity scores during stress (-1.02 ± 1.77 SD’s; r=0.62), and at rest (-1.10 ± 1.49 SD’s; r=0.61). There were no statistically significant differences between the methods regarding perfusion defect extent or severity. The overall agreement rate with coronary angiography was similar. OSEM 3D reconstruction algorithm significantly increases the image contrast by 31% (P<0.05). Conclusions: Compensation for detector response, attenuation and scatter improves image contrast compared with FBP. Applying quantitative analysis, OSEM 3D reconstruction produced increased image contrast compared to FBP, but similar results regarding the size and severity of left ventricular perfusion defects.

A comparative study of 99 Tc m N-mercaptopyridine-N-oxide and 99 Tc m -sestamibi myocardial perfusion imaging on acute myocardial infarction canine model

Objective The purpose of the present study is to compare the pharmacokinetic and biodistribution properties of 99Tcm N-mercaptopyridine-N-oxide (99 Tcm N-MPO) with 99 Tcm-sestamibi (99 Tcm-MIBI) in normal dogs, and to investigate the potential of 99TcmN-MPO as a myocardial perfusion agent in canines with acute myocardial infarction. Methods Twelve healthy mongrel dogs were injected intravenously with 99TcmN-MPO (n = 6) or 99Tcm-MIBI (n = 6). Tracer kinetics in body fluids were determined by collecting blood of 1 ml via a femoral vein catheter at 30 s, 1,2,3,4,5, 10, 20, 30, 40, 60and 90 min post-injection (p. i.). The collected blood samples were weighed and counted for radioactivity in a γ-counter. Anterior and posterior planar γ-camera images were collected at 10, 20, 30, 60, 90, and 120 min after injection, with organ uptake quantified by region-of-interest (ROIs) analysis. For comparison, 99Tcm-MIBI was also evaluated in the same twelve dogs. Canine infarct models were set up by micro-invasive interventional embolization. SPECT images in the canine infarct model were collected 24 hours after myocardial infarction at 30 min and 60 min after the administration of 99Tcm N-MPO (n = 5) or 99Tcm-MIBI (n = 5). Results Both of 99Tcm N-MPO and 99Tcm-M1BI had a rapid blood clearance with less than 50% of initial radioactivity remaining at 1 min [99TcmN-MPO: (35. 77 ± 6. 31)% ID/mg ,99Tcm-MIBI (34. 46 ± 6. 83) % ID/mg] and less than 5% at 30 min p. i. [99Tcm N-MPO(3. 11 ± 1.44) % ID/mg,99Tcm-MIBI (2.93 ±0. 39)% ID/mg] . After injection, 99TcmN-MPO showed significant accumulation in the myocardium and prolonged retention. This rapid liver clearance of 99TcmN-MPO led to favorable heart-to-liver ratios, reaching values of 0. 54 ±0. 06 at 10 min, 1.02 ±0. 06 at 30 min, and 1.38 ±0. 06 at 60 min p. i.In contrast, the heart/liver ratio of 99Tcm-MIBI remained low at all time points (0. 46 ± 0. 03 at 10 min,0. 63 ±0. 03 at 30 min, and 0. 62 ± 0. 12 at 60 min p. i.). SPECT imaging studies in canines with acute myocardial infarction indicated that good visualization of the left ventricular wall and perfusion defects could be achieved at 30 min after administration of 99TcmN-MPO, but not 99Tcm-MIBI. Conclusion The combination of high heart uptake and rapid liver clearance makes 99TcmN-MPO a promising new radiotracer for myocardial perfusion imaging. Key words: Myocardial infarction; Radioisotopes; Tomography, emission-computed,singlephoton

Persistent Chest Pain in Absence of Angiographic Significant Coronary Artery Disease is Associated with Permanent Myocardial Perfusion Defects in Magnetic Resonance Imaging in Post-menopausal Women

We studied a population of post-menopausal women with persistent chest pain (PChP) in order to investigate the relationship between myocardial perfusion at rest and during a stress test using magnetic resonance imaging (MRI). Our goals were to document whether transient myocardial perfusion is induced by dipyridamole infusion and if perfusion defects are also present at rest. The study population consisted of 45 consecutive women (mean age 57.6±8.7 years), who reported chest pain symptoms. PChP was defined as self-reported continuing chest pain after one year. We compared the results of the perfusion MRI studies in subgroups with and without obstructive coronary artery disease (CAD). The latest tools and technologies of Synapse™ Cardiovascular – Fujifilm’s cardiovascular (CV) image and information management system – helped us to achieve clear and comprehensive outcomes. In the group of women with PChP and non-obstructive CAD, 16 of 34 (48%) showed a well-evident left ventricular perfusion defect at baseline (four in one segment; eight in two segments and four in three or more segments). The localisation of the perfusion defects – seen using Synapse Cardiovascular – were anteroapical (n=6); septal (n=10); and inferoor inferolateral (n=4). These defects were ‘permanent’ or ‘fixed’, i.e. were present at rest and were neither induced nor modified by the administration of dipyridamole. In any of the women with CAD we found these anomalies. ‘Fixed’ perfusion defects at MRI – probably due to permanent damage of the coronary microcirculation – suggest a disease state typical for post-menopausal women with PChP.

Kinetic characterization of a novel cationic 99mTc(I)-tricarbonyl complex, 99mTc-15C5-PNP, for myocardial perfusion imaging

BackgroundIntense liver uptake of 99mTc-sestamibi (MIBI) often interferes with visualization of myocardial perfusion in the inferior wall of the left ventricle. To develop improved myocardial perfusion agents, crown ether-containing dithiocarbamates and bisphosphines have been introduced in recent years. This study was designed to investigate the myocardial imaging properties and in vivo kinetics of a cationic 99mTc(I)-tricarbonyl complex, 99mTc-15C5-PNP, in comparison with MIBI. MethodsDynamic cardiac images were acquired for 60 minutes after intravenous tracer injection using a small-animal SPECT system in healthy control rats and rats with myocardial infarcts. Myocardial and liver time-activity curves were generated for radiopharmaceutical kinetic analysis. ResultsGood visualization of the left ventricular wall and perfusion defects could be achieved 20 minutes after 99mTc-15C5-PNP administration. 99mTc-15C5-PNP images in all hearts with infarcts showed perfusion defects, which were comparable to MIBI images. The kinetic curves plotted from 1 to 60 minutes demonstrated that 99mTc-15C5-PNP has a shorter washout half-life (6.4 ± 3.2 vs 124 ± 30.5 minutes, P < .01) in the liver, lower residual liver activity (14.5 ± 10.2% vs 36.5 ± 28.9%, P < .01), and higher heart/liver ratio than MIBI. Conclusions99mTc-15C5-PNP has potential for rapid myocardial perfusion imaging with low liver uptake.

Evaluation of 99 mTcN-MPO as a New Myocardial Perfusion Imaging Agent in Normal Dogs and in an Acute Myocardial Infarction Canine Model: Comparison with 99 mTc-Sestamibi

(99) (m)TcN-MPO ([(99) (m)TcN(mpo)(PNP5)](+): mpo = 2-mercaptopyridine oxide and PNP5 = N-ethoxyethyl-N,N-bis[2-(bis(3-methoxypropyl)phosphino)ethyl]amine) is a cationic (99) (m)Tc-nitrido complex, which has favorable biodistribution and myocardial uptake with rapid liver clearance in Sprague Dawley rats. The objective of this study was to compare the biodistribution and pharmacokinetics of (99) (m)TcN-MPO and (99) (m)Tc-Sestamibi in normal dogs, and to evaluate the potential of (99) (m)TcN-MPO as a myocardial perfusion agent in canines with acute myocardial infarction. Five normal mongrel dogs were injected intravenously with (99) (m)TcN-MPO. Venous blood samples were collected via a femoral vein catheter at 0.5, 1, 2, 3, 4, 5, 10, 20, 30, 40, 60, and 90 min post-injection (p.i.). Anterior-posterior planar images were acquired by γ-camera at 10, 20, 30, 60, 90, and 120 min p.i. Regions of interest (ROIs) were drawn around the heart, liver, and lungs. The heart/liver and heart/lung ratios were calculated by dividing the mean counts in heart ROI by the mean counts in the liver and lung ROI, respectively. For comparison, (99) (m)Tc-sestamibi was also evaluated in the same five dogs. The interval period between the two examinations was 1 week to eliminate possible interference between these two radiotracers. In addition, single positron emission computed tomography (SPECT) images in the canine infarct model were collected 24 h after myocardial infarction at 30 and 60 min after the administration of (99) (m)TcN-MPO (n = 4) or (99) (m)Tc-Sestamibi (n = 4). It was found that (99) (m)TcN-MPO and (99) (m)Tc-Sestamibi displayed very similar blood clearance characteristics during the first 90 min p.i. Both (99) (m)TcN-MPO and (99) (m)Tc-Sestamibi had a rapid blood clearance with less than 50% of initial radioactivity remaining at 1 min and less than 5% at 30 min p.i. (99) (m)TcN-MPO and (99) (m)Tc-Sestamibi both showed good heart/lung contrast. The heart/liver ratio of (99) (m)TcN-MPO increased with time (0.53 ± 0.06 at 10 min, 0.90 ± 0.062 at 30 min, and 1.22 ± 0.06 at 60 min p.i.), whereas the heart/liver ratio of (99) (m)Tc-Sestamibi remained low at all time points (0.50 ± 0.03 at 10 min, 0.64 ± 0.03 at 30 min, and 0.60 ± 0.02 at 60 min p.i.). SPECT imaging studies in canines with acute myocardial infarction indicated that good visualization of the left ventricular wall and perfusion defects could be achieved at 30 min after administration of (99) (m)TcN-MPO but not after (99) (m)Tc-Sestamibi. The combination of reasonable heart uptake with rapid hepatobiliary excretion makes (99) (m)TcN-MPO a promising new radiotracer for myocardial perfusion imaging.

Regadenoson Induces Comparable Left Ventricular Perfusion Defects as Adenosine: A Quantitative Analysis From the ADVANCE MPI 2 Trial

This study sought to determine whether regadenoson induces left ventricular perfusion defects of similar size and severity as seen with adenosine stress. Total and ischemic left ventricular perfusion defect size predict patient outcome. Therefore, it is important to show that newer stressor agents induce similar perfusion abnormalities as observed with currently available ones. The ADVANCE MPI 2 (Adenosine versus Regadenoson Comparative Evaluation for Myocardial Perfusion Imaging) study was a prospective, double-blind, randomized trial comparing image results in patients undergoing standard gated adenosine single-photon emission computed tomography (SPECT) myocardial perfusion imaging who were then randomized in a 2:1 ratio to either regadenoson (N = 495) or a second adenosine SPECT (N = 260). Quantitative SPECT analysis was used to determine total left ventricular perfusion defect size and the extent of ischemia. Quantification was performed by a single observer who was blinded to randomization and image sequence. Baseline gated perfusion results were similar in patients randomized to adenosine or regadenoson. No significant differences in total (11.5 +/- 15.7 vs. 11.4 +/- 15.8, p = 0.88) or ischemic (4.8 +/- 9.2 vs. 4.6 +/- 8.9, p = 0.43) perfusion defect sizes were observed between the regadenoson and adenosine groups, respectively. Linear regression showed a close correlation between adenosine and regadenoson for total (r = 0.97, p < 0.001) and ischemic (r = 0.95, p < 0.001) left ventricular perfusion defects. Serial differences in total (-0.03 +/- 3.89 vs. -0.13 +/- 4.16, p = 0.73) and ischemic (0.15 +/- 4.08 vs. 0.25 +/- 3.81, p = 0.74) perfusion defect size and left ventricular ejection fraction (0.12 +/- 0.32 vs. 0.15 +/- 0.35, p = 0.27) from study 1 to study 2 were virtually identical in patients randomized to regadenoson versus adenosine, respectively. The good correlation between serial adenosine and regadenoson studies regarding total (0.41 +/- 5.43 vs. 0.21 +/- 5.23, p = 0.76) and ischemic (0.17 +/- 5.31 vs. 0.23 +/- 6.08, p = 0.94) perfusion defects persisted in the subgroup of 308 patients with an abnormal baseline SPECT. Applying quantitative analysis, regadenoson induces virtually identical scintigraphic results as adenosine regarding the size and severity of left ventricular perfusion defects and the extent of scintigraphic ischemia.

The Evolving Roles of Nuclear Cardiology

The use of cardiac imaging modalities has grown steadily, and cardiac nuclear studies constitute a large part of this number. Nuclear Cardiology is often mistakenly considered a synonym of myocardial perfusion imaging (MPI), but has broader applications, including metabolic imaging, innervation imaging, among other technologies. MPI has been a powerful diagnostic and prognostic tool in the assessment of patients for known or suspected CAD for decades, and is now increasingly used for the evaluation of the anti-ischemic effects of various therapies, according to changes in left ventricular perfusion defect size defined by sequential MPI. Neuronal dysfunction identified with iodine-123-metaiodobenzylguanidine may give information on prognosis in different disease conditions, such as after myocardial infarction, in diabetes and dilated cardiomyopathy. Molecular imaging may identify the predominant cellular population in the atherosclerotic plaque and help predict the likelihood of clinical events. Therefore, although its usefulness is well established, Nuclear Cardiology remains a moving science, whose roles keep in pace with evolving clinical needs and expectations.

Abstract 6131: Regadenoson Induces Perfusion Defects of Comparable Extent and Severity as Adenosine: A Quantitative Analysis from the ADVANCE 2 Trial

The quantified total and ischemic left ventricular (LV) perfusion defect size (PDS) is an important determinant of subsequent patient outcome. Therefore it is important to determine whether a new stressor agent induces similar perfusion abnormalities as a standard stressor agent such as adenosine. The ADVANCE 2 was a double-blind randomized trial comparing image results in patients undergoing standard adenosine (Ad) SPECT who were then randomized to either a second Ad SPECT (N=260) or SPECT following pharmacologic stress with Regadenoson (Reg) (N=493). All raw data of gated SPECT images (2 sets/patient) were reconstructed and reoriented in a standard fashion. Quantitative SPECT was performed using a previously validated automated program which determined the extent and severity of left ventricular (LV) perfusion defect size (PDS) and the extent of scintigraphic ischemia. PDS severity was defined as mild, moderate or severe based on the relation to normal pixel count activity (&gt;50%, 26–50%, and 0–25%, respectively). Quantification was performed blinded to randomization and image sequence. Baseline perfusion results were similar (p&gt;.05) between patients randomized to Ad vs Reg with respect to total (10.2±14.8 vs 11.5±15.8), ischemic (4.2±7.8 vs 4.6±8.9) and scar (6.0±10.7 vs 6.9±11.3) LV PDS. Results are summarized in the table below. Linear regression analysis showed a close correlation between Ad vs Reg for total (r=0.97, p&lt;.0001) and ischemic (0.94, p&lt;.0001) LV PDS. In this large database, quantitative SPECT analysis demonstrates that Regadenoson induces a comparable extent and severity of perfusion abnormality as induced with standard adenosine stress. This implies that similar prognostic information should be obtainable with Regadenoson stress as observed with adenosine.

Using the Consensus of Different Models to Predict Radiotherapy (RT)-induced Cardiac Perfusion Defects

Using the Consensus of Different Models to Predict Radiotherapy (RT)-induced Cardiac Perfusion Defects

An Unusual Case of Congenitally Corrected Transposition of the Great Arteries in the Elderly

A 56-year-old man1–4 with a history of mild dyspnea for several years and without cardiovascular risk factors was referred to our institution for coronary angiography. Before he was admitted to the hospital, a transthoracic 2-dimensional echocardiogram (TTE) was performed. The TTE was not diagnostic enough because of a suboptimal acoustic window and a technetium-99m single photon emission computed tomography pharmacological (dipyridamole) stress test that showed a mild, reversible left ventricular septal perfusion defect. On admission to our institution, the patient was asymptomatic and had no signs of heart failure on physical examination; however, a mild systolic (grade 2) murmur was heard on cardiac auscultation. An ECG at rest showed a sinus rhythm with normal PR interval and complete left bundle-branch block …

An Initial Strategy of Intensive Medical Therapy Is Comparable to That of Coronary Revascularization for Suppression of Scintigraphic Ischemia in High-Risk But Stable Survivors of Acute Myocardial Infarction

The purpose of this study was to determine the relative benefit of intensive medical therapy compared with coronary revascularization for suppressing scintigraphic ischemia. Although medical therapies can reduce myocardial ischemia and improve patient survival after acute myocardial infarction, the relative benefit of medical therapy versus coronary revascularization for reducing ischemia is unknown. A prospective randomized trial in 205 stable survivors of acute myocardial infarction was made to define the relative efficacy of an intensive medical therapy strategy versus coronary revascularization for suppressing scintigraphic ischemia as assessed by serial gated adenosine Tc-99m sestamibi myocardial perfusion tomography. All patients at baseline had large total (> or =20%) and ischemic (> or =10%) adenosine-induced left ventricular perfusion defects and an ejection fraction > or =35%. Imaging was performed during 1 to 10 days of hospital admission and repeated in an identical fashion after optimization of therapy. Patients randomized to either strategy had similar baseline demographic and scintigraphic characteristics. Both intensive medical therapy and coronary revascularization induced significant but comparable reductions in total (-16.2 +/- 10% vs. -17.8 +/- 12%; p = NS) and ischemic (-15 +/- 9% vs. -16.2 +/- 9%; p = NS) perfusion defect sizes. Likewise, a similar percentage of patients randomized to medical therapy versus coronary revascularization had suppression of adenosine-induced ischemia (80% vs. 81%; p = NS). Sequential adenosine sestamibi myocardial perfusion tomography can effectively monitor changes in scintigraphic ischemia after anti-ischemic medical or coronary revascularization therapy. A strategy of intensive medical therapy is comparable to coronary revascularization for suppressing ischemia in stable patients after acute infarction who have preserved LV function.