Myocardial Perfusion
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2021 ◽  
Author(s):  
Markus Henningsson ◽  
Carl-Johan Carlhäll ◽  
Tino Ebbers ◽  
Johan Kihlberg

Abstract Objective: To evaluate systolic flow-sensitive alternating inversion recovery (FAIR) during rest and exercise stress using 2RR (two cardiac cycles) or 1RR intervals between inversion pulse and imaging. Materials and Methods: 1RR and 2RR FAIR was implemented on a 3T scanner. Ten healthy subjects were scanned during rest and stress. Stress was performed using an in-bore ergometer. Heart rate, mean myocardial blood flow (MBF) and temporal signal-to-noise ratio (TSNR) were compared using paired t-tests. Results: Mean heart rate during stress was higher than rest for 1RR FAIR (85.8±13.7bpm vs 63.3±11.1bpm; p<0.01) and 2RR FAIR (83.8±14.2bpm vs 63.1±10.6bpm; p<0.01). Mean stress MBF was higher than rest for 1RR FAIR (2.97±0.76ml/g/min vs 1.43±0.6 ml/g/min; p<0.01) and 2RR FAIR (2.8±0.96 ml/g/min vs 1.22±0.59 ml/g/min; p<0.01). Resting mean MBF was higher for 1RR FAIR than 2RR FAIR (p<0.05), but not during stress. TSNR was lower for stress compared to rest for 1RR FAIR (4.52±2.54 vs 10.12±3.69; p<0.01) and 2RR FAIR (7.36±3.78 vs 12.41±5.12; p<0.01). 2RR FAIR TSNR was higher than 1RR FAIR for rest (p<0.05) and stress (p<0.001). Discussion: We have demonstrated feasibility of systolic FAIR in rest and exercise stress. 2RR delay systolic FAIR enables non-contrast perfusion assessment during stress with relatively high TSNR.


Author(s):  
Lennert Minten ◽  
Keir McCutcheon ◽  
Sander Jentjens ◽  
Maarten Vanhaverbeke ◽  
Vincent F.M. Segers ◽  
...  

Objective: Although coronary artery disease (CAD) is frequent in patients with aortic stenosis (AS), hemodynamic assessment of CAD severity in patients undergoing valve replacement for severe AS is challenging. Myocardial hypertrophic remodelling interferes with coronary blood flow and may influence the values of fractional flow reserve (FFR) and non-hyperemic pressure ratios (NHPRs). The aim is to investigate these effects on current CAD indices by comparing intra-coronary hemodynamics prior to, immediately after and six months after aortic valve replacement (AVR), when it is expected that microvascular function has improved. Furthermore, we will compare FFR and Resting Full Cycle Ratio (RFR) with myocardial perfusion SPECT as indicators of myocardial ischemia in patients with AS and CAD. Study design: One hundred patients with AS and CAD will be prospectively included. Patients will undergo pre-AVR SPECT and intra-coronary hemodynamic assessment at baseline, immediately after and six months after AVR. The primary endpoint is the change in FFR. Secondary endpoints include the acute change of FFR after TAVR, the diagnostic accuracy of FFR versus RFR compared with SPECT for the assessment of ischemia, changes in microvascular function as assessed by the index of microcirculatory resistance (IMR), and the effect of these changes on FFR.Conclusion: The present study will evaluate intra-coronary physiology before, immediately after and six months after AVR in patients with AS and intermediate coronary stenosis. The understanding of the impact of AVR on the assessment of FFR, NHPR and microvascular function may help guide the need for revascularization in these patients.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Valeria Cantoni ◽  
Roberta Green ◽  
Carlo Ricciardi ◽  
Roberta Assante ◽  
Leandro Donisi ◽  
...  

We compared the prognostic value of myocardial perfusion imaging (MPI) by conventional- (C-) single-photon emission computed tomography (SPECT) and cadmium-zinc-telluride- (CZT-) SPECT in a cohort of patients with suspected or known coronary artery disease (CAD) using machine learning (ML) algorithms. A total of 453 consecutive patients underwent stress MPI by both C-SPECT and CZT-SPECT. The outcome was a composite end point of all-cause death, cardiac death, nonfatal myocardial infarction, or coronary revascularization procedures whichever occurred first. ML analysis performed through the implementation of random forest (RF) and k -nearest neighbors (KNN) algorithms proved that CZT-SPECT has greater accuracy than C-SPECT in detecting CAD. For both algorithms, the sensitivity of CZT-SPECT (96% for RF and 60% for KNN) was greater than that of C-SPECT (88% for RF and 53% for KNN). A preliminary univariate analysis was performed through Mann-Whitney tests separately on the features of each camera in order to understand which ones could distinguish patients who will experience an adverse event from those who will not. Then, a machine learning analysis was performed by using Matlab (v. 2019b). Tree, KNN, support vector machine (SVM), Naïve Bayes, and RF were implemented twice: first, the analysis was performed on the as-is dataset; then, since the dataset was imbalanced (patients experiencing an adverse event were lower than the others), the analysis was performed again after balancing the classes through the Synthetic Minority Oversampling Technique. According to KNN and SVM with and without balancing the classes, the accuracy ( p value = 0.02 and p value = 0.01) and recall ( p value = 0.001 and p value = 0.03) of the CZT-SPECT were greater than those obtained by C-SPECT in a statistically significant way. ML approach showed that although the prognostic value of stress MPI by C-SPECT and CZT-SPECT is comparable, CZT-SPECT seems to have higher accuracy and recall.


2021 ◽  
Vol 8 ◽  
Author(s):  
Jei-Yie Huang ◽  
Chun-Kai Huang ◽  
Ruoh-Fang Yen ◽  
Kuo-Liong Chien ◽  
Yen-Wen Wu

Background: The aim of this study was to determine whether, and if so how, attenuation correction (AC) improves the diagnostic performance of myocardial perfusion imaging (MPI) in different coronary artery-supplied territories, using coronary angiography as the reference standard.Methods: PubMed and EMBASE were searched until December 2020 for studies evaluating AC MPI for the diagnosis of coronary artery disease (CAD) with vessel-based data. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool. For each study, the sensitivity, specificity, diagnostic odds ratios and areas under summary receiver operating characteristic curves (AUC) with 95% confidence intervals were calculated to determine the diagnostic accuracy of AC compared to non-AC MPI. A bivariate mixed-effects model was used to pool the data. Subgroup analyses considering the type of radiotracer and type of AC were performed.Results: A total of 264 articles were screened, of which 22 studies (2,608 patients) were enrolled. Significant improvements in specificity [0.78 vs. 0.58 in overall CAD, 0.87 vs. 0.61 in right coronary artery (RCA)] and diagnostic odds ratios (16 vs. 8 in overall CAD, 18 vs. 7 in RCA) after AC were shown in overall CAD at a patient level and RCA stenosis. Improvements in AUC were also noted. MPI had a similar diagnostic performance for detecting left anterior descending and left circumflex coronary artery stenosis with or without AC. There were trends of decreased sensitivity after AC, but none were significant. Diagnostic odds ratio showed significant improvement after AC only in the technetium-99m subgroup.Conclusion: The results of this study suggest that AC should be applied to MPI to improve the diagnosis of CAD regardless of which type of radiotracer, and that AC MPI can improve the specificity of detecting RCA stenosis.


2021 ◽  
Author(s):  
Brandon Harris ◽  
Stafford Warren ◽  
Eva Persson ◽  
Ravinay Bhindi ◽  
Michael Ringborn ◽  
...  

Background: There is sufficient collateral flow to prevent myocardial ischemia during balloon occlusion in approximately one in five patients. However, the magnitude of myocardial perfusion provided by the coronary collateral circulation during occlusion is unknown. Therefore, the aim of this study was to quantify collateral myocardial perfusion during balloon occlusion in patients with coronary artery disease (CAD). Methods: Patients without angiographically visible collaterals undergoing elective percutaneous transluminal coronary angioplasty (PTCA) to a single epicardial vessel underwent two scans with 99mTc-sestamibi myocardial perfusion single-photon emission computed tomography (SPECT). All subjects underwent at least three minutes of angiographically verified complete balloon occlusion, at which time an intravenous injection of the radiotracer was administered, followed by SPECT imaging. A second radiotracer injection followed by SPECT imaging was performed 24 hours after PTCA. Results: The study included 21 patients (median [interquartile range] age 70 [56-74] years, 48% female). The diameter stenosis ranged from 60-99%, with successful PTCA performed with a mean 5-minute balloon occlusion. The perfusion defect extent was 16 [8-30]% of the LV. The collateral perfusion at rest was 64 [58-68]% of normal perfusion. Collateral perfusion was negatively correlated with perfusion defect size (R2=0.85, p<0.001), and did not differ by sex (p=0.27) or age (p=0.58). Conclusions: This is the first study to describe the magnitude of coronary microvascular collateral perfusion in patients with CAD. On average, despite coronary occlusion and an absence of angiographically visible collateral vessels, collaterals provide approximately 60% of the perfusion that reaches the jeopardized myocardium during coronary occlusion.


2021 ◽  
Author(s):  
Ketina Arslani ◽  
Danielle M Gualandro ◽  
Christian Puelacher ◽  
Giovanna Lurati Buse ◽  
Andreas Lampart ◽  
...  

Abstract Background: Patients developing perioperative myocardial infarction/injury(PMI) have high mortality. PMI work-up and therapy remain poorly defined.Methods: In a prospective multicenter study enrolling high-risk patients undergoing major non-cardiac surgery within a systematic PMI screening and clinical response program, the frequency of cardiovascular imaging during PMI work-up and its yield for possible type 1 myocardial infarction(T1MI) was assessed. Automated PMI detection triggered evaluation by the treating physician/ cardiologist on service, who determined selection/timing of cardiovascular imaging. In transthoracic echocardiography(TTE) a new wall motion abnormality within 30days, in myocardial perfusion imaging(MPI) a new scar or ischemia within 90days, and in coronary angiography(CA) Ambrose-Type II or complex lesions within 7days of PMI detection were considered indicative of T1MI. Results: In patients with PMI, 21%(268/1269) underwent at least one cardiac imaging modality. TTE was used in 13%(163/1269), MPI in 3%(37/1269), and CA in 5%(68/1269). Consultation by a cardiologist, was associated with higher use of cardiaovascular imaging(27% versus 13%). Signs indicative of T1MI were found in 8% of TTE, 46% of MPI, and in 63% of CA. Conclusion: Most patients with PMI did not receive any cardiovascular imaging within their PMI work-up. If performed, MPI and CA have high yield for signs indicative of T1MI. Study registration: https://clinicaltrials.gov/ct2/show/NCT02573532


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