Coronary Magnetic Resonance Angiography Research Articles

Extended MRI-based PET motion correction for cardiac PET/MRI

PurposeA 2D image navigator (iNAV) based 3D whole-heart sequence has been used to perform MRI and PET non-rigid respiratory motion correction for hybrid PET/MRI. However, only the PET data acquired during the acquisition of the 3D whole-heart MRI is corrected for respiratory motion. This study introduces and evaluates an MRI-based respiratory motion correction method of the complete PET data.MethodsTwelve oncology patients scheduled for an additional cardiac 18F-Fluorodeoxyglucose (18F-FDG) PET/MRI and 15 patients with coronary artery disease (CAD) scheduled for cardiac 18F-Choline (18F-FCH) PET/MRI were included. A 2D iNAV recorded the respiratory motion of the myocardium during the 3D whole-heart coronary MR angiography (CMRA) acquisition (~ 10 min). A respiratory belt was used to record the respiratory motion throughout the entire PET/MRI examination (~ 30–90 min). The simultaneously acquired iNAV and respiratory belt signal were used to divide the acquired PET data into 4 bins. The binning was then extended for the complete respiratory belt signal. Data acquired at each bin was reconstructed and combined using iNAV-based motion fields to create a respiratory motion-corrected PET image. Motion-corrected (MC) and non-motion-corrected (NMC) datasets were compared. Gating was also performed to correct cardiac motion. The SUVmax and TBRmax values were calculated for the myocardial wall or a vulnerable coronary plaque for the 18F-FDG and 18F-FCH datasets, respectively.ResultsA pair-wise comparison showed that the SUVmax and TBRmax values of the motion corrected (MC) datasets were significantly higher than those for the non-motion-corrected (NMC) datasets (8.2 ± 1.0 vs 7.5 ± 1.0, p < 0.01 and 1.9 ± 0.2 vs 1.2 ± 0.2, p < 0.01, respectively). In addition, the SUVmax and TBRmax of the motion corrected and gated (MC_G) reconstructions were also higher than that of the non-motion-corrected but gated (NMC_G) datasets, although for the TBRmax this difference was not statistically significant (9.6 ± 1.3 vs 9.1 ± 1.2, p = 0.02 and 2.6 ± 0.3 vs 2.4 ± 0.3, p = 0.16, respectively). The respiratory motion-correction did not lead to a change in the signal to noise ratio.ConclusionThe proposed respiratory motion correction method for hybrid PET/MRI improved the image quality of cardiovascular PET scans by increased SUVmax and TBRmax values while maintaining the signal-to-noise ratio.Trial registration METC162043 registered 01/03/2017.

Diagnostic performance of 3.0 T unenhanced Dixon water-fat separation coronary MR angiography in patients with low-to-intermediate risk of coronary artery disease

PurposeTo evaluate the diagnostic performance of 3.0 T unenhanced compressed-sensing sensitivity encoding (CS-SENSE) Dixon water-fat separation coronary MR angiography (CMRA) in patients with low-to-intermediate risk of coronary artery disease (CAD) and its ability to grade the severity of CAD based on Coronary Artery Disease Reporting and Data System (CAD-RADS). MethodsA total of 55 patients who was clinically evaluated as low-to-intermediate risk of CAD were finally included to undergo both 3.0 T CS-SENSE water-fat separation CMRA and coronary computed tomography angiography (CCTA), and 11 of them also underwent X-ray coronary angiography (CAG). The severity of coronary artery disease was graded in patients who had completed both CCTA and CMRA examinations by the use of CAD-RADS reports for the patients with stable chest pain, and the diagnostic consistency between the two approaches was evaluated. Diagnostic performance of CMRA was assessed using the combination of CCTA and CAG as the reference standard for excluding or confirming CAD respectively. ResultsThe sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy of 3.0 T unenhanced water-fat separation coronary MRA were 90.0%, 95.0%, 81.8%, 97.4% and 94.0% for a patient-based analysis respectively. In comparison with CCTA, 3.0 T Dixon water-fat separation CMRA demonstrated excellent consistency in grading the severity of coronary heart disease according to CAD-RADS (0.77 for kappa value). ConclusionIn the group of low-to-intermediate probability for CAD, 3.0 T unenhanced CS-SENSE Dixon water-fat separation CMRA can present satisfactory diagnostic performance for the exclusion of CAD with high sensitivity and negative predictive value as well as the evaluation of grading the severity of coronary artery disease.

MRI Diagnosis of Coronary Artery Lesions in Children With Kawasaki Disease and Their Correlation With Inflammatory Factors.

Ultrasonography (US), as a routine examination for evaluating coronary artery lesions (CAL) in children with Kawasaki disease (KD), has strong subjectivity and limitations. Non-contrast enhanced coronary magnetic resonance angiography (NCE-CMRA) is sensitive and reliable in displaying the segments of coronary arteries (CA). To evaluate the CA using NCE-CMRA, to compare NCE-CMRA with US, and to assess the correlation between KD-related inflammatory factors and the occurrence of CAL. Retrospective. 61 children with KD who had undergone NCE-CMRA. Ultimately, 52 cases were included (32 males and 20 females), with an average of 5.9 ± 0.3 years old. 3-T, 3D balanced turbo field echo sequence. NCE-CMRA and US coronary visualization rates were compared in 41 children who were imaged with both techniques. Inflammatory factors were compared between CAL and normal coronary artery (NCA) subgroups. In the CAL group, correlations of these inflammatory factors with CAL parameters were investigated. Comparison between groups was performed by the two independent samples t-test; the comparison of enumeration data between groups was performed by chi-square test. Receiver operating characteristic (ROC) curve analysis was performed to determine the sensitivity of inflammatory factors for detecting CAL. The correlation between CAL and inflammatory indexes was analyzed by multiple linear regression. A P value <0.05 was considered statistically significant. NCE-CMRA visualized significantly more segments than US (76% vs. 46%). There were significant differences in PLT, CRP, ESR, and D-dimer between the CAL and NCA groups. ROC curve analysis showed that the sensitivities of these four indicators in diagnosing CAL were 39%, 44%, 72%, and 61%, respectively, at cut-off points of 562.5 × 109 /L, 48.93 mg/L, 45.5 mm/h, and 0.5 mg/L, respectively. The combination of NCE-CMRA and inflammatory factors is helpful for the early diagnosis and disease severity of CAL in children with KD. 3 TECHNICAL EFFICACY: Stage 2.

Comparison between diaphragmatic-navigated and self-navigated coronary magnetic resonance angiography at 3T in pediatric patients with congenital coronary artery anomalies.

Coronary magnetic resonance angiography (CMRA) is being increasingly used in pediatric patients with congenital coronary artery anomalies (CAAs). However, the data on the free-breathing self-navigation technique, which has the potential to simplify the acquisition plan with a high success rate at 3T, remain scarce. This study investigated the clinical application value of self-navigated (sNAV) CMRA at 3T in pediatric patients with suspected CAAs and compared it to conventional diaphragmatic-navigated (dNAV) CMRA. From April 2019 to March 2022, we enrolled 65 pediatric patients (38 males and 27 females; mean age 8.5±4.4 years) with suspected CAAs in this prospective study. All patients underwent both dNAV and sNAV sequences in random order with gradient recalled echo (GRE) sequence during free breathing, with 39 (20 males and 19 females; mean age 10.2±3.6 years) of them additionally undergoing coronary computed tomography angiography (CCTA) or invasive coronary angiography (ICA). We measured and compared the success rate, scan time, visual score of the 9 main coronary artery segments, vessel sharpness, and vessel length between the two sequences. The diagnostic accuracy was compared using CCTA or ICA as a reference. The success rate of sNAV-CMRA (65/65, 100%) was higher than that of dNAV-CMRA (61/65, 93.8%) (P<0.001), and the scan time of sNAV-CMRA (7.3±2.5 min) was significantly shorter than that of dNAV-CMRA (9.1±3.6 min) (P=0.002). The acquisition efficiency of dNAV-CMRA was 40.5%±12.9%, while for sNAV-CMRA, 100% acquisition efficiency was achieved. There was no significant difference in vessel length of any of the coronary arteries, visual score, or vessel sharpness of the left circumflex coronary artery (LCX) between the two sequences (all P values >0.050). The visual score and vessel sharpness of the right coronary artery and left anterior descending coronary artery (LAD) were significantly improved in dNAV-CMRA compared with sNAV-CMRA (all P values <0.050). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the detection of CAAs were not significantly different between the two sequences (all P values >0.050). Our findings demonstrated that both sNAV and dNAV in CMRA provide clinical application value in pediatric patients with CAAs and have similar diagnostic performance. Although the image quality of sNAV-CMRA is slightly inferior compared to that of dNAV-CMRA, sNAV-CMRA allows for a simpler scanning procedure.

Optimal Protocol for Contrast-enhanced Free-running 5D Whole-heart Coronary MR Angiography at 3T.

Free-running 5D whole-heart coronary MR angiography (MRA) is gaining in popularity because it reduces scanning complexity by removing the need for specific slice orientations, respiratory gating, or cardiac triggering. At 3T, a gradient echo (GRE) sequence is preferred in combination with contrast injection. However, neither the injection scheme of the gadolinium (Gd) contrast medium, the choice of the RF excitation angle, nor the dedicated image reconstruction parameters have been established for 3T GRE free-running 5D whole-heart coronary MRA. In this study, a Gd injection scheme, RF excitation angles of lipid-insensitive binominal off-resonance RF excitation (LIBRE) pulse for valid fat suppression and continuous data acquisition, and compressed-sensing reconstruction regularization parameters were optimized for contrast-enhanced free-running 5D whole-heart coronary MRA using a GRE sequence at 3T. Using this optimized protocol, contrast-enhanced free-running 5D whole-heart coronary MRA using a GRE sequence is feasible with good image quality at 3T.

Kiosk 9R-TC-01 - Deep Learning-based Super Resolution for 3D Whole-heart Coronary MR Angiography

Kiosk 9R-TC-01 - Deep Learning-based Super Resolution for 3D Whole-heart Coronary MR Angiography

Kiosk 11R-TB-08 - Feasibility of Inav-based FBee-breathing Non-contrast Coronary MRA at 0.7mm3 Resolution

Kiosk 11R-TB-08 - Feasibility of Inav-based FBee-breathing Non-contrast Coronary MRA at 0.7mm3 Resolution

CMR 2-62 - Development of Computer-aided Detection of Significant Coronary Artery Stenosis in Whole-heart Coronary MRA Using Deep Convolutional Neural Network

CMR 2-62 - Development of Computer-aided Detection of Significant Coronary Artery Stenosis in Whole-heart Coronary MRA Using Deep Convolutional Neural Network

Feasibility study of the multishot gradient-echo planar imaging sequence in non-enhanced and free-breathing whole-heart magnetic resonance coronary angiography

To investigate the feasibility of non-enhanced and free-breathing whole-heart magnetic resonance coronary angiography (MRCA) using multishot gradient-echo planar imaging (MSG-EPI). In total, 29 healthy volunteers were recruited for free-breathing whole-heart MRCA acquisition using the MSG-EPI sequence and fast gradient echo (GRE) sequence. After the examination, the actual scanning times, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) of the left main (LM) coronary artery, subjective quality scores for each segment, and evaluable length of the coronary artery were recorded and statistically analysed. There was no significant difference between the SNRLM of the MSG-EPI sequence and fast GRE sequence (p=0.130), but the CNRLM of the MSG-EPI sequence was higher (p=0.001). The subjective quality score of the mid- and distal left anterior descending branch as well as the distal circumflex branch of the coronary artery in the MSG-EPI sequence was higher than that in the fast GRE sequence (p=0.003, 0.001, and 0.003, respectively). The evaluable length of the left anterior descending branch and the circumflex branch was better using the MSG-EPI sequence than that of the fast GRE sequence (p=0.015 and<0.001, respectively). Moreover, the scanning time of the MSG-EPI sequence was 54.5% less than that of the fast GRE sequence (p<0.001). The MSG-EPI sequence improves the subjective and objective image quality of MRCA as well as reduces the scanning time.

Simultaneous, free-breathing, non-contrast 3D whole-heart coronary magnetic resonance angiography and vulnerable plaque imaging in patients with suspected acute coronary syndrome

Abstract Background Coronary artery high-risk plaque identified on cardiovascular magnetic resonance (CMR) is associated with future coronary events, independent of coronary artery luminal stenosis. We have recently developed a 3-dimensional whole-heart free-breathing non-contrast CMR sequence that allows for simultaneous high-resolution visualisation of the coronary arteries and vulnerable plaque on co-registered bright and black blood images (iT2prep-BOOST) with 100% respiratory scan efficiency. Objectives To validate iT2prep-BOOST in patients with non-ST-segment elevation myocardial infarction (NSTEMI) against the reference standard imaging modalities of invasive X-ray coronary angiography and intravascular imaging [optical coherence tomography (OCT)/intravascular ultrasound (IVUS)]. Methods 41 consecutive patients with suspected NSTEMI, based upon clinical history, electrocardiographic changes and positive high-sensitivity troponin assays, were recruited into the study. Invasive coronary angiography ± intravascular imaging was used to classify coronary segments into the following categories: normal, non-culprit and culprit segments; stenosed segments as well as segments with vulnerable plaque features (lipid, calcium, fibroatheroma, thin cap fibroatheroma (TCFA), plaque rupture and thrombus). The highest plaque/myocardial signal intensity ratio (PMR) in each coronary segment was analysed on iT2prep-BOOST. Results The mean iT2prep-BOOST acquisition time was 10.8 ± 1.3 minutes. The mean ± standard error of mean (SEM) PMR of culprit segments was significantly higher than non-culprit segments, which was significantly higher than normal segments (1.01 ± 0.05 vs. 0.67 ± 0.01 vs. 0.35 ± 0.01, P&amp;lt;0.001). Coronary segments with lipid, calcium and fibroatheroma had a significantly higher PMR compared to normal coronary segments (P&amp;lt;0.001) but lower than segments with TCFA, plaque rupture and thrombus (P&amp;lt;0.001). There was a progressive increase in PMR with increasing degree of coronary stenosis (P&amp;lt;0.001). Patients with type 2 diabetes, hypertension, hyperlipidaemia and family history of coronary artery disease had a significantly higher PMR on iT2prep-BOOST (P&amp;lt;0.001, P=0.02, P=0.04 and P=0.02 respectively). Finally, PMR was positively correlated with HbA1c, total cholesterol, non-HDL cholesterol, LDL cholesterol and triglyceride levels (P&amp;lt;0.001, P=0.02, P=0.02, P=0.05 and P=0.05 respectively). Conclusions In summary, the proposed iT2prep-BOOST framework has the potential to simultaneously acquire coronary artery angiography and to differentiate normal segments from non-culprit and culprit plaque segments. Furthermore, PMR is associated with both biochemical and patient related risk factors for coronary artery disease (CAD). The long-term prognostic value of PMR needs to be investigated in a longitudinal multi-centre study of patients with suspected CAD.Figure 1Figures 2 and 3

Abstract 17209: Late Gadolinium Enhancement by Cardiovascular Magnetic Resonance versus Invasive Coronary Angiography: A Meta-Analysis on Diagnostic Accuracy for Cardiovascular Ischemia

Introduction: Invasive Coronary Angiography (ICA) has been the gold standard for diagnosing cardiovascular ischemia, however, it carries an inherent risk due to its invasive nature. Late Gadolinium Enhancement (LGE) by Cardiovascular Magnetic Resonance (CMR) is a promising non-invasive alternative. This necessitates determining its diagnostic accuracy to inform clinical decision-making. Hypothesis: This study aims to assess the diagnostic accuracy of LGE by CMR and ICA in detecting cardiovascular ischemia. Methods: We performed a systematic review of studies until January 2023 across multiple databases, including PubMed, Embase, and the Cochrane Library, that compared the diagnostic accuracy of LGE by CMR and ICA for cardiovascular ischemia. Diagnostic performance measures, including sensitivity, specificity, false-positive rate estimates, diagnostic odds ratio, and positive and negative Likelihood Ratios (LR), were pooled using a random-effects model and presented with a 95% Confidence Interval (CI). R software (version 4.0.3) with the mada package was utilized for statistical analyses. Results: Our meta-analysis collected data from 8 studies encompassing 1,020 patients, of which 395 had confirmed ischemic imaging and 625 had confirmed non-ischemic heart imaging. The results revealed that LGE by CMR had high diagnostic accuracy for detecting cardiovascular ischemia. The sensitivity was 90.9% (95% CI: 80.2%-96.1%, I2=50.4%), the specificity was 89.3% (95% CI: 79.2%-94.8%, I2=90.5%), and the false-positive rate was 10.7% (95% CI: 5.2%-20.8%). The diagnostic odds ratio for LGE by CMR was 82.82 (95% CI: 25.2-272.5), and the positive and negative Likelihood Ratios were 8.46 (95% CI: 4.19-17.06) and 0.10 (95% CI: 0.05-0.23), respectively. Conclusions: This study demonstrates the high diagnostic accuracy of LGE by CMR for cardiovascular ischemia, as indicated by its high sensitivity, specificity, and substantial diagnostic odds ratio. These findings suggest that LGE by CMR could be a reliable non-invasive alternative to ICA, potentially improving clinical decision-making and reducing risks associated with invasive imaging. Further studies and policy reviews are needed to optimize the use of this promising diagnostic modality.

Nonischemic or Dual Cardiomyopathy in Patients With Coronary Artery Disease.

Randomized trials in obstructive coronary artery disease (CAD) have largely shown no prognostic benefit from coronary revascularization. Although there are several potential reasons for the lack of benefit, an underexplored possible reason is the presence of coincidental nonischemic cardiomyopathy (NICM). We investigated the prevalence and prognostic significance of NICM in patients with CAD (CAD-NICM). We conducted a registry study of consecutive patients with obstructive CAD on coronary angiography who underwent contrast-enhanced cardiovascular magnetic resonance imaging for the assessment of ventricular function and scar at 4 hospitals from 2004 to 2020. We identified the presence and cause of cardiomyopathy using cardiovascular magnetic resonance imaging and coronary angiography data, blinded to clinical outcomes. The primary outcome was a composite of all-cause death or heart failure hospitalization, and secondary outcomes were all-cause death, heart failure hospitalization, and cardiovascular death. Among 3023 patients (median age, 66 years; 76% men), 18.2% had no cardiomyopathy, 64.8% had ischemic cardiomyopathy (CAD+ICM), 9.3% had CAD+NICM, and 7.7% had dual cardiomyopathy (CAD+dualCM), defined as both ICM and NICM. Thus, 16.9% had CAD+NICM or dualCM. During a median follow-up of 4.8 years (interquartile range, 2.9, 7.6), 1116 patients experienced the primary outcome. In Cox multivariable analysis, CAD+NICM or dualCM was independently associated with a higher risk of the primary outcome compared with CAD+ICM (adjusted hazard ratio, 1.23 [95% CI, 1.06-1.43]; P=0.007) after adjustment for potential confounders. The risks of the secondary outcomes of all-cause death and heart failure hospitalization were also higher with CAD+NICM or dualCM (hazard ratio, 1.21 [95% CI, 1.02-1.43]; P=0.032; and hazard ratio, 1.37 [95% CI, 1.11-1.69]; P=0.003, respectively), whereas the risk of cardiovascular death did not differ from that of CAD+ICM (hazard ratio, 1.15 [95% CI, 0.89-1.48]; P=0.28). In patients with CAD referred for clinical cardiovascular magnetic resonance imaging, NICM or dualCM was identified in 1 of every 6 patients and was associated with worse long-term outcomes compared with ICM. In patients with obstructive CAD, coincidental NICM or dualCM may contribute to the lack of prognostic benefit from coronary revascularization.

Self-navigated coronary MR angiography for coronary aneurysm detection in Kawasaki disease at 3T: comparison with conventional diaphragm-navigated coronary MR angiography.

To assess the scan time, image quality, and diagnostic performance of self-navigated coronary MR angiography (SN-CMRA) for coronary aneurysm (CAA) detection in Kawasaki disease (KD) patients and compare it with diaphragm-navigated CMRA (DN-CMRA). SN-CMRA and DN-CMRA were performed on 76 pediatric patients with KD (48 males, 6.75 ± 3.59 years). Thirty-three of whom underwent coronary CT angiography (CCTA)/invasive coronary angiography (ICA). The scan time and qualitative and quantitative image quality assessment were compared between the two sequences. The diagnostic performance for CAA detection by the two approaches using CCTA/ICA as the reference standard was compared on per-patient, per-vessel, and per-segment basis. The scan time of SN-CMRA was significantly shorter than that of DN-CMRA (7.49 ± 2.31 min vs. 10.03 ± 4.47 min, p< 0.001). There was no difference in overall and segmental image quality to reach the clinical diagnostic criteria between the two sequences (all p> 0.05). No significant difference in vessel length of the three main coronary arteries was found between the two approaches (all p> 0.05). Moreover, SN-CMRA showed no difference from DN-CMRA in contrast ratio of blood-myocardium (1.25 (interquartile range [IQR], 1.06 to 1.51) vs. 1.18 (IQR, 0.95 to 1.64), p= 0.706). There was no difference in the diagnostic accuracy of SN-CMRA and DN-CMRA for CAA detection on per-patient, per-vessel, or per-segment basis (all p> 0.05). SN-CMRA at 3T showed reliable diagnostic performance and application value for CAA detection in children with KD. Compared with DN-CMRA, SN-CMRA can simplify the scanning procedure and shorten the scan time, achieving comparable image quality and diagnostic accuracy. Coronary aneurysm in children with Kawasaki disease (KD) can be detected by self-navigated coronary MR angiography (CMRA) non-invasively and without radiation, achieving comparable image quality and diagnostic performance as diaphragm-navigated CMRA while shortening scanning time. It can provide reference for risk stratification and treatment management of KD. • Evaluating the size of coronary aneurysm is important for risk stratification and treatment of Kawasaki disease. • Self-navigated coronary MR angiography (SN-CMRA) shortens scan time and achieves comparable image quality and diagnostic performance compared with diaphragm-navigated coronary MR angiography. • SN-CMRA can evaluate coronary aneurysm non-invasively and without radiation, providing information for risk stratification and treatment.

Sex-specific and ethnicity-specific differences in MINOCA.

Suspected myocardial infarction with non-obstructive coronary arteries (MINOCA) has received increasing attention over the past decade. Given the heterogeneity in the mechanisms underlying acute myocardial infarction in the absence of obstructive coronary arteries, the syndrome of MINOCA is considered a working diagnosis that requires further investigation after diagnostic angiography studies have been performed, including coronary magnetic resonance angiography and functional angiography. Although once considered an infrequent and low-risk form of myocardial infarction, recent data have shown that the prognosis of MINOCA is not as benign as previously assumed. However, despite increasing awareness of the condition, many questions remain regarding the diagnosis, risk stratification and treatment of MINOCA. Women seem to be more susceptible to MINOCA, but studies on the sex-specific differences of the disease are scarce. Similarly, ethnicity-specific factors might explain discrepancies in the observed prevalence or underlying pathophysiological mechanisms of MINOCA but data are also scarce. Therefore, in this Review, we provide an update on the latest evidence available on the sex-specific and ethnicity-specific differences in the clinical features, pathophysiological mechanisms, treatment and prognosis of MINOCA.

Multicentre medicoeconomic evaluation of cardiac magnetic resonance imaging for predicting coronary artery disease in left ventricular dysfunction: The CAMAREC study design

BackgroundCardiac magnetic resonance imaging may provide a non-invasive alternative to coronary angiography for differentiating between ischaemic and non-ischaemic cardiomyopathy in cases of unexplained reduced left ventricular ejection fraction. AimThe CAMAREC study aims to evaluate the diagnostic accuracy of cardiac magnetic resonance imaging in predicting significant coronary artery disease in patients with reduced left ventricular ejection fraction, using coronary angiography as the gold standard for comparison. MethodsCAMAREC is a prospective cohort study of 406 patients in 10 centres with newly diagnosed, unexplained left ventricular ejection fraction ≤ 45%. Cardiac magnetic resonance imaging and coronary angiography will be conducted within a 2-week interval, starting with cardiac magnetic resonance imaging; independent committees will review the results blindly. Primary outcome is sensitivity of detecting ischaemic scar on cardiac magnetic resonance imaging for predicting significant coronary artery disease on coronary angiography according to Felker's criteria. Secondary outcomes include specificity and positive and negative predictive values (with 95% confidence intervals) of cardiac magnetic resonance imaging for predicting significant coronary artery disease in patients with reduced left ventricular ejection fraction, kappa concordance coefficient between cardiac magnetic resonance imaging and coronary angiography for diagnosing the affected myocardial territory, and the impact of cardiac magnetic resonance imaging on revascularization decisions. Two ancillary studies will evaluate the incremental cost-effectiveness of using cardiac magnetic resonance imaging first versus coronary angiography first, and the sensitivity of pre- and postcontrast T1-mapping for predicting significant coronary artery disease in patients with reduced left ventricular ejection fraction. ConclusionOur study protocol is designed to rigorously evaluate cardiac magnetic resonance imaging as a non-invasive alternative to coronary angiography in patients with unexplained reduced left ventricular ejection fraction. The results will have significant implications for patient management, and may support growing evidence for the clinical utility of cardiac magnetic resonance imaging.

3.0 T unenhanced Dixon water-fat separation whole-heart coronary magnetic resonance angiography: compressed-sensing sensitivity encoding imaging versus conventional 2D sensitivity encoding imaging.

This study was aimed to investigate 3.0 T unenhanced Dixon water-fat whole-heart CMRA (coronary magnetic resonance angiography) using compressed-sensing sensitivity encoding (CS-SENSE) and conventional sensitivity encoding (SENSE) in vitro and in vivo. The key parameters of CS-SENSE and conventional 1D/2D SENSE were compared in vitro phantom study. In vivo study, fifty patients with suspected coronary artery disease (CAD) completed unenhanced Dixon water-fat whole-heart CMRA at 3.0 T using both CS-SENSE and conventional 2D SENSE methods. We compared mean acquisition time, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and the diagnostic accuracy between two techniques. In vitro study, CS-SENSE achieved better effectiveness between higher SNR/CNR and shorter scan times using the appropriate acceleration factor compared with conventional 2D SENSE. In vivo study, CS-SENSE CMRA had better performance than 2D SENSE in terms of the mean acquisition time, SNR and CNR (7.4 ± 3.2min vs. 8.3 ± 3.4min, P = 0.001; SNR: 115.5 ± 35.4 vs. 103.3 ± 32.2; CNR: 101.1 ± 33.2 vs. 90.6 ± 30.1, P < 0.001 for both). The diagnostic accuracy between CS-SENSE and 2D SENSE had no significant difference on a patient-based analysis (sensitivity: 97.3% vs. 91.9%; specificity: 76.9% vs. 61.5%; accuracy: 92.0% vs. 84.0%; P > 0.05 for each). Unenhanced CS-SENSE Dixon water-fat separation whole-heart CMRA at 3.0 T can improve the SNR and CNR, shorten the acquisition time while providing equally satisfactory image quality and diagnostic accuracy compared with 2D SENSE CMRA.

Diagnostic Performance and Safety of a Novel Ferumoxytol-Enhanced Coronary Magnetic Resonance Angiography.

Currently, noninvasive arteriography for the diagnosis of coronary artery disease is clinically limited to the computed tomography scanning, where patients have to be exposed to the radiation and risks associated with iodinated contrast. We aimed to investigate the diagnostic performance and safety of a novel ferumoxytol-enhanced coronary magnetic resonance angiography (CMRA) in patients with suspected coronary artery disease. Thirty patients, 19 males, with a median age of 63 years old, and 17 with renal insufficiency, who were scheduled for invasive coronary angiography, were enrolled. Ferumoxytol was administered intravenously with a dose of 3 mg/kg during CMRA. Images were acquired with an ECG-triggered, navigator-gated, inversion recovery-prepared 3D fast low-angle shot sequence, and the image quality was assessed by a 4-point scale. Eighteen-segment coronary artery model was adopted to evaluate the visibility of the coronary arteries, and the image quality and stenosis were evaluated in nine segments. The diagnostic performance of CMRA is described as sensitivity, specificity, positive and negative predictive values, and accuracy with the invasive coronary angiography results as reference. The patients' vital signs were monitored during CMRA, and their hepatic and renal functions were followed up for 3 months to evaluate the safety of ferumoxytol. Two hundred fifty-two of the 270 study segments were identified by CMRA, and their quality score reached 3.6±0.7. Referring to the invasive coronary angiography results, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of ferumoxytol-enhanced CMRA reached 100.0%, 66.7%, 92.3%, 100.0%, and 93.3% respectively in patient-based analysis; 91.4%, 90.9%, 86.5%, 94.3%, and 91.1%, respectively in vessel-based analysis; and 92.3%, 96.7%, 83.7%, 98.6%, and 96.0%, respectively in segment-based analysis. No ferumoxytol-related adverse event was observed during the 3-month follow-up. Ferumoxytol-enhanced CMRA demonstrated good diagnostic performance and excellent safety in the diagnosis of significant coronary stenosis, providing an alternative to coronary computed tomography angiography for the diagnosis of coronary artery disease. URL: https://www. gov; Unique identifier: NCT05032937.

Cardiac fibroblast activation after acute myocardial infarction: pilot study using technetium 99m-iFAP SPECT

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Instituto Nacional de Investigaciones Nucleares (ININ). Background/Introduction Excessive fibrosis and persistent active fibroblasts can lead to increased left ventricular stiffness and, thus, heart failure. Cardiac remodeling is an important factor in the prognosis of patients after an acute myocardial infarction (AMI), and fibroblast activation is mandatory for repair and regeneration of the damage. There's an increasing use of molecular imaging in cardiovascular processes, such as molecules targeting fibroblast activation protein (FAP). FAP inhibitors (iFAP) radiolabeled with 68Ga in PET/CT have demonstrated adequate biodistribution and high uptake by activated fibroblasts in patients with cardiovascular risk factors and after acute myocardial infarction. Unfortunately, PET is not always widely available or cost-effective. Purpose This pilot study evaluates the feasibility of imaging activated fibroblast using 99mTc-iFAP SPECT in patients after AMI and its correlation with myocardial perfusion imaging (MPI), cardiac magnetic resonance (CMR) and invasive coronary angiography (ICA). Methods A prospective study with recent first AMI and non-previous known coronary artery disease patients were included. They underwent 99mTc-MIBI MPI SPECT and 99mTc-iFAP SPECT (including whole-body scan and thorax anterior static image acquired at 20, 60, and 120 min for the iFAP) and CMR/ICA within 14 days (+-2) after AMI. Qualitative and quantitative analysis was performed using a 17 segments model using QPS (Cedars Sinai) to determine the infarct extension from MPI and the correlation with the 99mTc-iFAP uptake pattern. A visual grading scale was established to assess localized tracer uptake and segments belonging to the hypoperfused area of the culprit's vessel. CMR yielded an area of injury with late gadolinium enhancement (LGE) and correlated with MPI studies. Results Five patients with STEMI were included (mean age of 63). Localized uptake of 99mTc-iFAP was observed in all patients with according to the affected coronary territory detected by ICA in 100% of patients (four anterior STEMI, one inferior STEMI). No radiotracer uptake was observed in the non-infarcted territories. Agreement between myocardial iFAP uptake, MIBI myocardial perfusion defect, CMR LGE, and ICA findings are presented in figure 1. An agreement of mismatch in polar maps between iFAP and MPI was performed, obtaining an excellent mismatch pattern in all patients, especially in transmural infarct segments. The best quality image was obtained at 60 minutes. Conclusions We successfully carried out the first pilot study with the patented 99mTc-iFAP molecule with SPECT technique. 99mTc-iFAP is a promising novel biomarker in assessing myocardial injury in sites where PET/CT is unavailable. There is an excellent correlation between iFAP uptake with the perfusion defect, LGE, and invasive anatomical obstruction findings. It is feasible and necessary to extend the inclusion of patients to a larger sample.

Feasibility of accelerated non-contrast-enhanced whole-heart bSSFP coronary MR angiography by deep learning-constrained compressed sensing.

To examine a compressed sensing artificial intelligence (CSAI) framework to accelerate image acquisition in non-contrast-enhanced whole-heart bSSFP coronary magnetic resonance (MR) angiography. Thirty healthy volunteers and 20 patients with suspected coronary artery disease (CAD) scheduled for coronary computed tomography angiography (CCTA) were enrolled. Non-contrast-enhanced coronary MR angiography was performed with CSAI, compressed sensing (CS), and sensitivity encoding (SENSE) methods in healthy participants and with CSAI in patients. Acquisition time, subjective image quality score, and objective image quality measurement (blood pool homogeneity, signal-to-noise ratio [SNR], and contrast-to-noise ratio [CNR]) were compared among the three protocols. The diagnostic performance of CASI coronary MR angiography for predicting significant stenosis (≥ 50% diameter stenosis) on CCTA was evaluated. The Friedman test was performed to compare the three protocols. Acquisition time was significantly shorter in the CSAI and CS groups than in the SENSE group (10.2 ± 3.2min vs. 10.9 ± 2.9min vs. 13.0 ± 4.1min, p < 0.001). However, the CSAI approach had the highest image quality scores, blood pool homogeneity, mean SNR value, and mean CNR value (all p < 0.001) compared with the CS and SENSE approaches. The sensitivity, specificity, and accuracy of CSAI coronary MR angiography per patient were 87.5% (7/8), 91.7% (11/12), and 90.0% (18/20); those per vessel were 81.8% (9/11), 93.9% (46/49), and 91.7% (55/60); and those per segment were 84.6% (11/13), 98.0% (244/249), and 97.3% (255/262), respectively. CSAI yielded superior image quality within a clinically feasible acquisition time in healthy participants and patients with suspected CAD. The non-invasive and radiation-free CSAI framework could be a promising tool for rapid screening and comprehensive examination of the coronary vasculature in patients with suspected CAD. • This prospective study showed that CSAI enables a reduction in acquisition time by 22% with superior diagnostic image quality compared with the SENSE protocol. • CSAI replaces the wavelet transform with a CNN as a sparsifying transform in the CS algorithm, achieving high coronary MR image quality with reduced noise. • CSAI achieved per-patient sensitivity of 87.5% (7/8) and specificity of 91.7% (11/12) respectively for detecting significant coronary stenosis.

Fully automated pixel-wise quantitative CMR-myocardial perfusion with CMR-coronary angiography to detect hemodynamically significant coronary artery disease.

We applied a fully automated pixel-wise post-processing framework to evaluate fully quantitative cardiovascular magnetic resonance myocardial perfusion imaging (CMR-MPI). In addition, we aimed to evaluate the additive value of coronary magnetic resonance angiography (CMRA) to the diagnostic performance of fully automated pixel-wise quantitative CMR-MPI for detecting hemodynamically significant coronary artery disease (CAD). A total of 109 patients with suspected CAD were prospectively enrolled and underwent stress and rest CMR-MPI, CMRA, invasive coronary angiography (ICA), and fractional flow reserve (FFR). CMRA was acquired between stress and rest CMR-MPI acquisition, without any additional contrast agent. Finally, CMR-MPI quantification was analyzed by a fully automated pixel-wise post-processing framework. Of the 109 patients, 42 patients had hemodynamically significant CAD (FFR ≤ 0.80 or luminal stenosis ≥ 90% on ICA) and 67 patients had hemodynamically non-significant CAD (FFR ˃ 0.80 or luminal stenosis < 30% on ICA) were enrolled. On the per-territory analysis, patients with hemodynamically significant CAD had higher myocardial blood flow (MBF) at rest, lower MBF under stress, and lower myocardial perfusion reserve (MPR) than patients with hemodynamically non-significant CAD (p < 0.001). The area under the receiver operating characteristic curve of MPR (0.93) was significantly larger than those of stress and rest MBF, visual assessment of CMR-MPI, and CMRA (p < 0.05), but similar to that of the integration of CMR-MPI with CMRA (0.90). Fully automated pixel-wise quantitative CMR-MPI can accurately detect hemodynamically significant CAD, but the integration of CMRA obtained between stress and rest CMR-MPI acquisition did not provide significantly additive value. • Full quantification of stress and rest cardiovascular magnetic resonance myocardial perfusion imaging can be postprocessed fully automatically, generating pixel-wise myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) maps. • Fully quantitative MPR provided higher diagnostic performance for detecting hemodynamically significant coronary artery disease, compared with stress and rest MBF, qualitative assessment, and coronary magnetic resonance angiography (CMRA). • The integration of CMRA and MPR did not significantly improve the diagnostic performance of MPR alone.