Perfusion In Coronary Artery Disease Research Articles

Value of Dynamic Computed Tomography Myocardial Perfusion in CAD: A Systematic Review and Meta-analysis.

Dynamic stress computed tomography (CT) perfusion is a non-invasive method for quantifying myocardial ischemia by assessing myocardial blood flow (MBF). In this meta-analysis, we evaluated the diagnostic accuracy of dynamic CT perfusion for the detection of significant coronary artery disease (CAD) across various CT scanners, obese patients, and its prognostic value. We systematically searched PubMed, Embase, Web of Science, and Cochrane library for published studies evaluating the accuracy of CT myocardial perfusion in diagnosing functional significant ischemia by invasive fractional flow reserve. The diagnostic performance of dynamic CT perfusion in detecting ischemia was evaluated using a summary receiver operating characteristic (sROC) curve. A total of 23 studies underwent meta- analysis. In myocardial region without ischemia, MBF was measured at 1.44 ml/min/g (95% confidence interval [CI]: 1.13-1.75), while in region with ischemia, it was 0.94 ml/min/g (95% CI: 0.80-1.08) (p<0.001). On the patient-based analysis, the area under the sROC curve of CT-MBF was 0.93, with a sensitivity of 0.84 and specificity of 0.88. Differences in CT type (dual source vs. single source), and body mass index (BMI) did not significantly affect the diagnostic performance. The pooled hazard ratio of dynamic CT perfusion for predicting adverse events was 4.98 (95%CI: 2.08-11.93, p=<0.001, I2=61%, p for heterogeneity = 0.07). Dynamic CT perfusion has high diagnostic performance in the quantitative assessment of ischemia and detection of functional myocardial ischemia as defined by invasive FFR, and may be useful in risk stratification of CAD patients.

Static CT myocardial perfusion imaging: image quality, artifacts including distribution and diagnostic performance compared to 82Rb PET

BackgroundRubidium-82 positron emission tomography (82Rb PET) MPI is considered a noninvasive reference standard for the assessment of myocardial perfusion in coronary artery disease (CAD) patients. Our main goal was to compare the diagnostic performance of static rest/ vasodilator stress CT myocardial perfusion imaging (CT-MPI) to stress/ rest 82Rb PET-MPI for the identification of myocardial ischemia.MethodsForty-four patients with suspected or diagnosed CAD underwent both static CT-MPI and 82Rb PET-MPI at rest and during pharmacological stress. The extent and severity of perfusion defects on PET-MPI were assessed to obtain summed stress score, summed rest score, and summed difference score. The extent and severity of perfusion defects on CT-MPI was visually assessed using the same grading scale. CT-MPI was compared with PET-MPI as the gold standard on a per-territory and a per-patient basis.ResultsOn a per-patient basis, there was moderate agreement between CT-MPI and PET-MPI with a weighted 0.49 for detection of stress induced perfusion abnormalities. Using PET-MPI as a reference, static CT-MPI had 89% sensitivity (SS), 58% specificity (SP), 71% accuracy (AC), 88% negative predictive value (NPV), and 59% positive predictive value (PPV) to diagnose stress-rest perfusion deficits on a per-patient basis. On a per-territory analysis, CT-MPI had 73% SS, 65% SP, 67% AC, 90.8% NPV, and 34% PPV to diagnose perfusion deficits.ConclusionsCT-MPI has high sensitivity and good overall accuracy for the diagnosis of functionally significant CAD using 82Rb PET-MPI as the reference standard. CT-MPI may play an important role in assessing the functional significance of CAD especially in combination with CCTA.

Quantitative myocardial perfusion in coronary artery disease: A perfusion mapping study.

BackgroundCardiac MR stress perfusion remains a qualitative technique in clinical practice due to technical and postprocessing challenges. However, automated inline perfusion mapping now permits myocardial blood flow (MBF, ml/g/min) quantification on‐the‐fly without user input.PurposeTo investigate the diagnostic performance of this novel technique in detecting occlusive coronary artery disease (CAD) in patients scheduled to undergo coronary angiography.Study TypeProspective, observational.SubjectsFifty patients with suspected CAD and 24 healthy volunteers.Field Strength1.5T.Sequence"Dual" sequence multislice 2D saturation recovery.AssessmentAll patients underwent cardiac MR with perfusion mapping and invasive coronary angiography; the healthy volunteers had MR with perfusion mapping alone.Statistical TestsComparison between numerical variables was performed using an independent t‐test. Receiver operator characteristic (ROC) curves were generated for transmyocardial, endocardial stress MBF, and myocardial perfusion reserve (MPR, the stress:rest MBF ratio) to diagnose severe (>70%) stenoses as measured by 3D quantitative coronary angiography (QCA). ROC curves were compared by the method of DeLong et al.ResultsCompared with volunteers, patients had lower stress MBF and MPR even in vessels with <50% stenosis (2.00 vs. 3.08 ml/g/min, respectively). As stenosis severity increased (<50%, 50–70%, >70%), MBF and MPR decreased. To diagnose occlusive (>70%) CAD, endocardial and transmyocardial stress MBF were superior to MPR (area under the curve 0.92 [95% CI 0.86–0.97] vs. 0.90 [95% CI 0.84–0.95] and 0.80 [95% CI 0.72–0.87], respectively). An endocardial threshold of 1.31 ml/g/min provided a per‐coronary artery sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 90%, 82%, 50%, and 98%, with a per‐patient diagnostic performance of 100%, 66%, 57%, and 100%, respectively.Data ConclusionPerfusion mapping can diagnose occlusive CAD with high accuracy and, in particular, high sensitivity and NPV make it a potential "rule‐out" test. Level of Evidence: 1 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2019;50:756–762.

Quantitative Perfusion Analysis of First-Pass Contrast Enhancement Kinetics: Application to MRI of Myocardial Perfusion in Coronary Artery Disease.

PurposePerfusion analysis from first-pass contrast enhancement kinetics requires modeling tissue contrast exchange. This study presents a new approach for numerical implementation of the tissue homogeneity model, incorporating flexible distance steps along the capillary (NTHf).MethodsThe proposed NTHf model considers contrast exchange in fluid packets flowing along the capillary, incorporating flexible distance steps, thus allowing more efficient and stable calculations of the transit of tracer through the tissue. We prospectively studied 8 patients (62 ± 13 years old) with suspected CAD, who underwent first-pass perfusion CMR imaging at rest and stress prior to angiography. Myocardial blood flow (MBF) and myocardial perfusion reserve index (MPRI) were estimated using both the NTHf and the conventional adiabatic approximation of the TH models. Coronary artery lesions detected at angiography were clinically assigned to one of three categories of stenosis severity (‘insignificant’, ‘mild to moderate’ and ‘severe’) and related to corresponding myocardial territories.ResultsThe mean MBF (ml/g/min) at rest/stress and MPRI were 0.80 ± 0.33/1.25 ± 0.45 and 1.68 ± 0.54 in the insignificant regions, 0.74 ± 0.21/1.09 ± 0.28 and 1.54 ± 0.46 in the mild to moderate regions, and 0.79 ± 0.28/0.63 ± 0.34 and 0.85 ± 0.48 in the severe regions, respectively. The correlation coefficients of MBFs at rest/stress and MPRI between the NTHf and AATH models were r = 0.97/0.93 and r = 0.91, respectively.ConclusionsThe proposed NTHf model allows efficient quantitative analysis of the transit of tracer through tissue, particularly at higher flow. Results of initial application to MRI of myocardial perfusion in CAD are encouraging.

3 Tesla is the preferred field strength for perfusion imaging in coronary artery disease – a comparison to 1.5 Tesla and fractional flow reserve

Background Adenosine perfusion imaging at 1.5 Tesla (T) has been shown to yield good diagnostic values in comparison to quantitative coronary angiography. Perfusion imaging at 3 T has the potential benefit of higher contrast- and signalto-noise ratios. However, little is known about diagnostic performance of 3 T perfusion imaging in comparison to 1.5 T and in comparison to invasive measurement of fractional flow reserve (FFR). We sought to evaluate visual and quantitative assessment of adenosine perfusion at 3 T in comparison to 1.5 T and to coronary angiography in patients presenting with suspected coronary artery disease (CAD). Methods 86 consecutive patients with suspected CAD were enrolled in this study. All patients underwent adenosine perfusion at 3 T (Achieva, Philips Medical Systems) and 1.5 T (Intera, Philips Medical Systems) within 72 hours with subsequent coronary angiography within 72 hours. Two independent patient groups were formed. In group 1 1 (N=52) quantitative coronary analysis (QCA) was compared to qualitative perfusion MRI imaging. Group 2 (N=34) underwent FFR measurement in all three major coronary arteries in comparison to quantitative myocardial perfusion reserve (MPR). Results In both groups a significant (p<0.05) higher sensitivity and specificity (group 1: 0.88 vs 0.80 and 0.96 vs. 0.89, p<0.01; group 2 0.91 vs. 0.62 and 1.0 vs. 0.77, p<0.001) was found for 3 T when compared to 1.5 T. Conclusions 3 T appears to be the superior field strength for visual or quantitative analysis of myocardial perfusion in CAD as shown in our two consecutive patient groups.

MRI of Intimal Sarcoma of the Pulmonary Arteries

A 38-year-old woman presented with left lower chest pain. At the age of 3 years, a commissurotomy of the pulmonary valve and infundibulectomy was performed to correct severe infundibular pulmonary stenosis. The initial thoracic CT diagnosed bilateral pulmonary embolism. Echocardiography revealed a filiforme mass in the pulmonary artery 33 mm in length, floating in the right outflow tract, suggesting a pulmonary sarcoma. In addition, a moderate pulmonary valve insufficiency with mild stenosis was diagnosed. Cardiac magnetic resonance (CMR) confirmed the mass in the left pulmonary artery (PA) with floating parts and a small mass in the right PA (Figure 1) and provided complementary findings identifying …

Comparison of Automated 4D-MSPECT and Visual Analysis for Evaluating Myocardial Perfusion in Coronary Artery Disease

The aim of this study was to assess the reproducibility and diagnostic performance for coronary artery disease (CAD) of an automated software package, 4D-MSPECT, and compare the results with a visual approach. We enrolled 60 patients without previously known CAD, who underwent dual-isotope rest Tl-201/stress Tc-99m sestamibi myocardial perfusion imaging and subsequent coronary angiography within 3 months. The automated summed stress score (A-SSS), summed rest score (A-SRS) and summed difference score (A-SDS) were obtained using a 17-segment five-point scale model with 4D-MSPECT. For intraobserver and interobserver variability assessment, automated scoring was done by a nuclear medicine physician twice and by a nuclear medicine technologist. The visual summed stress score (V-SSS), summed rest score (V-SRS), and summed difference score (V-SDS) were obtained by consensus of two nuclear medicine physicians. The intraobserver and interobserver agreements of automated segmental scores were excellent. The intraobserver and interobserver summed scores also correlated well. Agreements between visual and automated segmental scores were moderate (weighted kappa of 0.55 and 0.50 for stress and rest images, respectively). Correlations between automated and visual summed scores were high, with correlation coefficients of 0.89, 0.85 and 0.82 for SSS, SRS and SDS, respectively (all p < 0.001). The receiver operating characteristic area under the curve for diagnosis of CAD by V-SSS, V-SDS, A-SSS and A-SDS were 0.78 +/- 0.06, 0.87 +/- 0.05, 0.84 +/- 0.05 and 0.90 +/- 0.04, respectively. A-SDS had better diagnostic performance than A-SSS and V-SSS (p = 0.043 and p = 0.032, respectively), whereas there was no statistically significant difference between A-SDS and V-SDS (p = 0.56). Using V-SDS > or = 2 as a diagnostic threshold, the sensitivity, specificity, and accuracy for CAD were 83.7%, 76.5% and 81.7%, respectively. Using A-SDS > or = 3 as a diagnostic threshold, the sensitivity, specificity, and accuracy for CAD were 79.1%, 82.4% and 80.0%, respectively. In conclusion, the reproducibility of automated semiquantitative analysis with 4D-MSPECT was excellent. The diagnostic performance of automated semiquantitative analysis with 4D-MSPECT was comparable with the visual approach.

Blood pressure elevation after phenylephrine infusion may adversely affect myocardial perfusion in patients with coronary artery disease

Background: Although blood pressure is a major determinant of myocardial oxygen-demand, little information is currently available regarding the changes in blood pressure (BP) during myocardial ischemia. Since BP elevation may cause left ventricular (LV) wall stress and an increase in oxygen demand, infusion of an α-adrenergic agonist, such as phenylephrine (PH), may provoke changes in myocardial perfusion in coronary artery disease (CAD) patients. As the effects of BP changes alone on myocardial perfusion have never been assessed by thallium-201 (Tl) scintigraphy, we investigated the effects of BP elevation after PH infusion, in order to study the hypothesis that pressure loading alone without increases in heart rate, may provoke transient impairment of regional myocardial perfusion, in CAD patients. Patients and methods: Forty-one (41) patients with angiographically documented CAD, aged 54±8 years, were included in our study. Each patient was given, without any complications, a PH (0.1 mg/ml) dose infused at a rate of 0.8 ml/mm, determined by a standardisation procedure and producing a mean blood pressure elevation of approximately 30% above baseline levels and a heart rate response to levels of no less than 50 bpm. One minute after the desired blood pressure and heart rate responses were reached, 2 mCi of Tl were injected and the PH infusion continued until the termination of the test. Tl scintigraphy was performed both 2 min after Tl injection and 4 h later, while the results were correlated to coronary angiography findings. Results: PH scintigraphy produced 152 total defects. The mean perfusion defect size (%) was 14±12 and was directly related to the number of diseased vessels, i.e., 2% for one-vessel disease, 15% for two-vessel disease and 25% for three-vessel disease ( P<0.05). The lowest percentage Tl activity values were 56±14 and were inversely related to the number of diseased vessels ( P<0.01). The mean Tl lung counts/pixel values were 25±8 while it increased as the number of diseased vessels increased ( P<0.01). The mean lung/heart ratio values were 0.31±0.08 while it increased as the number of diseased vessels increased ( P<0.01). Conclusion: BP elevation after PH loading, produces a significant impairment of myocardial perfusion, that correlates well with the extend of angiographic findings.

Factor Analysis of Medical Image Sequences Improves Evaluation of First-Pass MR Imaging Acquisitions for Myocardial Perfusion

Rationale and Objectives Factor analysis of medical image sequences (FAMIS) applied to gadolinium chelate–enhanced subsecond magnetic resonance (MR) imaging was evaluated as a postprocessing method for assessing myocardial perfusion in coronary artery disease (CAD). Materials and Methods To assess the accuracy of motion correction, five normal volunteers underwent MR imaging at rest. Thirteen patients with well-documented CAD and no myocardial infarction underwent MR imaging at rest and after dipyridamole administration. After motion correction, a single myocardial tissue factor (FAMISt) image was obtained with FAMIS for each raw MR imaging series acquisition. To evaluate how FAMIS could improve the analysis of these acquisitions, five readers visually assessed myocardial perfusion with FAMISt and raw MR images, and a multicase, multi–reader receiver operating characteristic analysis was performed. Results FAMISt images significantly improved detection of the perfusion defects when compared with raw MR images ( P = .002). Areas under the receiver operating characteristic curves ranged from 0.84 to 0.93 with FAMISt images and from 0.48 to 0.85 with raw MR images. Conclusion FAMIS applied to first-pass MR imaging series provided myocardial perfusion images that improve the objective assessment of myocardial perfusion in patients with CAD.

Assessment of myocardial perfusion in coronary artery disease using myocardial contrast echocardiography

MCE has evolved over the past decade as a clinically useful technique for the assessment of myocardial perfusion in patients with coronary artery disease. At present, its applications are limited because of the necessity of injecting microbubbles directly into the arterial circulation. Newer contrast agents, capable of producing myocardial opacification from a venous injection, are likely to broaden significantly the application of this technique in patients with coronary artery disease. Advances in ultrasound technology, such as second-harmonic imaging will make MCE a valuable non-invasive method, capable of simultaneously assessing regional perfusion and function. The advent of ultrasound systems that provide a linear relationship between the tissue concentration of microbubbles and the video intensity will make the method truly quantitative. It is likely that MCE will replace nuclear cardiology for the assessment of myocardial dysfunction by the turn of the century in many patients with coronary artery disease.

Noninvasive evaluation of regional myocardial perfusion with positron emission computed tomography.

Positron emission computed tomography (PET) offers regional measurement of physiological and biochemical processes in vivo. We have constructed a whole-body multislice PET scanner, which provides 7 tomographic images at 16 mm intervals simultaneously. The high sensitivity with good spatial resolution of this system permits dynamic studies of the heart. PET scan of the heart was performed following intravenous bolus injection of 13N labeled ammonia. Serial dynamic images in normal cases showed early accumulation of tracer in the myocardium and rapid clearance from the cardiac blood pool. Delayed clearance from the blood and prolonged retention in the dorsal part of the lungs were observed in cases with myocardial infarction. A perfusion defect was clearly visualized in myocardial infarction except for infarction of the inferior wall. Transient ischemia was also visualized with exercise loading. Thus, PET with 13N ammonia is a valuable diagnostic tool for the evaluation of regional myocardial perfusion in coronary artery disease.

Esophageal acid perfusion in coronary artery disease: Induction of myocardial ischemia

Although coronary artery disease and gastroesophageal reflux disease are common conditions which, therefore, may coexist, it is unknown whether or not the presence of one affects the other. We performed esophageal acid perfusion tests, with concurrent blood pressure, heart rate, and 12-lead electrocardiographic monitoring, in 37 patients, 25 with angiographically documented coronary disease and 12 with normal coronary arteries. Rate—pressure product, an index of myocardial work load, was calculated. In patients with coronary disease who developed chest pain during acid perfusion, rate-pressure product increased from 10.0 ± 1.0 × 103 (mean ± SEM) basally to 15.2 ± 1.5 × 103 (p < 0.001), and 3 of 9 patients showed concomitant electrocardiogram evidence of myocardial ischemia. In addition, in coronary disease, 64% of patients with infrequent or absent reflux symptoms by history had positive acid perfusion tests, and 56% of patients with coronary disease who developed pain during esophageal acid perfusion could not distinguish that pain from their usual angina. We conclude that in coronary disease, acid perfusion (and, presumably, gastroesophageal reflux) resulting in chest pain causes rate—pressure product elevation and can induce myocardial ischemia. The presence of esophageal acid sensitivity is not accurately predicted by clinical history in coronary disease, and pain of esophageal origin is often confused with angina.

Effects of exercise training on left ventricular performance and myocardial perfusion in patients with coronary artery disease

To determine the effects of exercise training on left ventricular performance and myocardial perfusion in coronary artery disease, rest and exercise radionuclide angiocardiography and thallium-201 scintigraphy were performed before and after 12 weeks of training in 16 coronary patients. After training, 15 of the 16 patients had improved exercise tolerance; total treadmill exercise duration increased from (mean ± standard error of the mean) 491 ± 37 to 602 ± 31 seconds (p < 0.01), and the estimated rate of oxygen consumption (VO 2 max) increased from 29.4 ± 1.4 to 33.8 ± 1.2 ml/kg per min (p < 0.001). Resting left ventricular ejection fraction increased from 52 ± 4 to 57 ± 4 percent (p < 0.02); no change occurred in left ventricular functional reserve assessed by ejection fraction and regional wall motion response to exercise at the same ratepressure product before and after training. Myocardial perfusion at equivalent pre- and post-training cardiac work loads during exercise and on redistribution was unchanged by training. It is concluded that in patients with coronary heart disease, physical training increases exercise tolerance, and results in minimal improvement in resting left ventricular systolic performance. Functional reserve of both left ventricular systolic performance and the coronary circulation appears to be unchanged by exercise training. These data suggest that the beneficial effects of training for 12 weeks in patients with coronary artery disease predominantly result from factors other than improvement in left ventricular pump performance or perfusion.

Inequalities of myocardial perfusion in coronary artery disease ("coronary steal").

Inequalities of myocardial perfusion in coronary artery disease ("coronary steal").