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Value CMR: Towards a Comprehensive, Rapid, Cost-Effective Cardiovascular Magnetic Resonance Imaging.

ABSTRACT: Cardiac magnetic resonance imaging (CMR) is considered the gold standard for measuring cardiac function. Further, in a single CMR exam, information about cardiac structure, tissue composition, and blood flow could be obtained. Nevertheless, CMR is underutilized due to long scanning times, the need for multiple breath-holds, use of a contrast agent, and relatively high cost. In this work, we propose a rapid, comprehensive, contrast-free CMR exam that does not require repeated breath-holds, based on recent developments in imaging sequences. Time-consuming conventional sequences have been replaced by advanced sequences in the proposed CMR exam. Specifically, conventional 2D cine and phase-contrast (PC) sequences have been replaced by optimized 3D-cine and 4D-flow sequences, respectively. Furthermore, conventional myocardial tagging has been replaced by fast strain-encoding (SENC) imaging. Finally, T1 and T2 mapping sequences are included in the proposed exam, which allows for myocardial tissue characterization. The proposed rapid exam has been tested in vivo. The proposed exam reduced the scan time from >1 hour with conventional sequences to <20 minutes. Corresponding cardiovascular measurements from the proposed rapid CMR exam showed good agreement with those from conventional sequences and showed that they can differentiate between healthy volunteers and patients. Compared to 2D cine imaging that requires 12-16 separate breath-holds, the implemented 3D-cine sequence allows for whole heart coverage in 1-2 breath-holds. The 4D-flow sequence allows for whole-chest coverage in less than 10 minutes. Finally, SENC imaging reduces scan time to only one slice per heartbeat. In conclusion, the proposed rapid, contrast-free, and comprehensive cardiovascular exam does not require repeated breath-holds or to be supervised by a cardiac imager. These improvements make it tolerable by patients and would help improve cost effectiveness of CMR and increase its adoption in clinical practice.

SUBMITTER: Ibrahim EH

PROVIDER: S-EPMC8147553 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Cardiovascular magnetic resonance (CMR) is increasingly used to assess patients with mitral regurgitation. Its advantages include quantitative determination of ventricular volumes and function and the mitral regurgitant fraction, and in ischemic mitral regurgitation, regional myocardial function and viability. In addition to these, identification of leaflet prolapse or restriction is necessary when valve repair is contemplated. We describe a systematic approach to the evaluation of mitral regurgitation using CMR which we have used in 149 patients with varying etiologies and severity of regurgitation over a 15 month period. Following standard ventricular cine acquisitions, including 2, 3 and 4 chamber long axis views and a short axis stack for biventricular function, we image movements of all parts of the mitral leaflets using a contiguous stack of oblique long axis cines aligned orthogonal to the central part of the line of coaptation. The 8-10 slices in the stack, orientated approximately parallel to a 3-chamber view, are acquired sequentially from the superior (antero-lateral) mitral commissure to the inferior (postero-medial) commissure, visualising each apposing pair of anterior and posterior leaflet scallops in turn (A1-P1, A2-P2 and A3-P3). We use balanced steady state free precession imaging at 1.5 Tesla, slice thickness 5 mm, with no inter-slice gaps. Where the para-commissural coaptation lines curve relative to the central region, two further oblique cines are acquired orthogonal to the line of coaptation adjacent to each commissure. To quantify mitral regurgitation, we use phase contrast velocity mapping to measure aortic outflow, subtracting this from the left ventricular stroke volume to calculate the mitral regurgitant volume which, when divided by the left ventricular stroke volume, gives the mitral regurgitant fraction. In patients with ischemic mitral regurgitation, we further assess regional left ventricular function and, with late gadolinium enhancement, myocardial viability. Comprehensive assessment of mitral regurgitation using CMR is feasible and enables determination of mitral regurgitation severity, associated leaflet prolapse or restriction, ventricular function and viability in a single examination and is now routinely performed at our centre. The mitral valve stack of images is particularly useful and easy to acquire.

Project description:BackgroundMyocardial perfusion cardiovascular magnetic resonance (CMR) is a well-established method for detection of ischemic heart disease. However, ECG gating problems can result in image degradation and non-diagnostic scans, particularly in patients with arrhythmias.MethodsA turboFLASH saturation recovery pulse sequence was used without any ECG triggering. One saturation pulse followed by 4-5 slices of undersampled radial k-space images was acquired rapidly, on the order of 40-50 msec per image. The acquisition of the set of 4-5 slices was continuously repeated approximately 4 times per second. An iterative constrained reconstruction method was used to reconstruct the ungated images. The ungated perfusion images were post-processed into three different sets of images (ungated, self-gated to near systole, and self-gated to near diastole). To test the ungated approach and compare the different processing methods, 8 patients scheduled for coronary angiography underwent stress and rest perfusion imaging with the ungated acquisition. Six patients had a history of atrial fibrillation (AF). Three blinded readers assessed image quality and presence/absence of disease.ResultsAll 8 subjects successfully completed the perfusion CMR protocol and 7/8 underwent coronary angiography. Three patients were in atrial fibrillation during CMR. Overall, the CMR images were of high quality as assessed by the three readers. There was little difference in image quality between patients in AF compared to those in sinus rhythm (3.6±0.7 vs. 3.3±0.5). Stress/rest perfusion imaging showed normal perfusion in 4 patients, fixed perfusion defects in 2 patients, and reversible perfusion defects in 2 patients, corresponding with angiographic results. Pooled results from the independent readers gave a sensitivity of 0.92 (CI 0.65-0.99) and specificity of 0.92 (CI 0.65-0.99) for the detection of coronary artery disease using ungated perfusion imaging. The same sensitivity, and a specificity of 1 (CI 0.76-1), was achieved when the images were self-gated after acquisition into near systole or near diastole.ConclusionsUngated radial dynamic perfusion CMR can give high quality imaging in patients in sinus rhythm and during atrial fibrillation. In this small cohort, high diagnostic accuracy was possible with this rapid perfusion imaging sequence. An ungated approach simplifies the acquisition and could expand the role of perfusion CMR to include patients with arrhythmia and those with gating problems.

Project description:Pompe disease is an autosomal recessive disorder caused by deficiency of the lysosomal α-1,4-glucosidase leading to accumulation of glycogen in target tissues with progressive organ failure. While the early infantile-onset form is characterized by early severe hypertrophic cardiomyopathy with cardiac and respiratory failure, clinically relevant cardiomyopathy seems to be uncommon in patients with late-onset Pompe disease, and the prevalence and nature of myocardial abnormalities are still to be clarified.Seventeen patients with genetically proven late-onset Pompe disease (50 ± 18 years, 11 male) and 18 age- and gender-matched healthy controls (44 ± 10 year, 12 male) underwent comprehensive cardiovascular magnetic resonance (CMR) including conventional and advanced techniques: cine and feature tracking-based strain imaging for depiction of (even subtle) systolic LV dysfunction as well as late gadolinium enhancement (LGE) and myocardial extracellular volume fraction (ECV) quantification for focal and diffuse fibrosis detection.All patients had normal left ventricular (LV) and right ventricular (RV) volumes and normal LV and RV ejection fraction. In comparison to healthy controls, neither conventional cine nor advanced feature-tracking based-strain imaging could depict any (subclinical) myocardial systolic dysfunction. Three (18%) of the patients had non-ischemic LGE in the basal inferolateral wall and 21% demonstrated elevated global ECV values suggestive of interstitial myocardial fibrosis. Non-specific abnormalities such as left atrial (LA) dilatation were present in two patients, while LV hypertrophy was seen only in one. Two of the three LGE-positive patients were also hypertensive and demonstrated high global ECV values (>30%) in addition to dilated LA. After a median follow-up of 25 (11-29) months, only one cardiovascular event occurred: one of the LGE-positive patients with a high cardiovascular risk profile suffered an acute coronary syndrome.In contrast to the early infantile-onset form of Pompe disease, mild and rather non-specific cardiac abnormalities can be detected by CMR only in a small proportion of patients with late-onset Pompe disease. The observed structural abnormalities seem to result from an interplay between the storage disease and other comorbidities and they did not affect short-term to mid-term prognosis in adult Pompe patients.

Project description:BackgroundWhile current guidelines recommend noninvasive testing to detect coronary artery disease, stress tests are deemed inconclusive in a quarter of cases. The strategy for risk stratification after inconclusive stress testing is not well standardized. To assess the prognostic value of vasodilator stress cardiovascular magnetic resonance (CMR) parameters and CMR-based coronary revascularization in patients after inconclusive stress testing.MethodsBetween 2008 and 2020, consecutive patients with a first non-CMR inconclusive stress test referred for vasodilator stress perfusion CMR were followed for the occurrence of major adverse cardiovascular events (MACE), defined by cardiovascular death or nonfatal myocardial infarction. CMR-related coronary revascularization was defined as any revascularisation occurring within 90 days after CMR. Univariable and multivariable Cox regressions were performed to determine the prognostic value of each parameter.ResultsOf 1563 patients who completed the CMR protocol, 1402 patients (66.7% male, 69.5 ± 11.0 years) completed the follow-up (median [interquartile range], 6.5 [5.6-7.5] years); 197 experienced a MACE (14.1%). Vasodilator stress CMR was well tolerated without severe adverse events. Using Kaplan-Meier analysis, inducible ischemia and late gadolinium enhancement (LGE) were significantly associated with the occurrence of MACE (hazard ratio, HR: 2.88 [95% CI 2.18-3.81]; and HR: 1.46 [95% CI 1.16-1.89], both p < 0.001; respectively). In multivariable Cox regression, the presence and extent of inducible ischemia were independent predictors of a higher incidence of MACE (HR: 2.53 [95% CI 1.89-3.40]; and HR: 1.58 [95% CI 1.47-1.71]; both p < 0.001; respectively). After adjustment, the extent of inducible ischemia showed the best improvement in model discrimination above traditional risk factors (C-statistic 0.75 [95% CI 0.69-0.81] with C-statistic improvement: 0.12). The study suggested no benefit of CMR-related coronary revascularization in reducing MACE.ConclusionsIn patients with a first non-CMR inconclusive stress test, vasodilator stress CMR has good prognostic value to predict MACE offering an incremental prognostic value over traditional risk factors.

Project description:BackgroundCardiovascular magnetic resonance (CMR) is the gold standard method for the assessment of cardiac structure and function. Reference ranges permit differentiation between normal and pathological states. To date, this study is the largest to provide CMR specific reference ranges for left ventricular, right ventricular, left atrial and right atrial structure and function derived from truly healthy Caucasian adults aged 45-74.MethodsFive thousand sixty-five UK Biobank participants underwent CMR using steady-state free precession imaging at 1.5 Tesla. Manual analysis was performed for all four cardiac chambers. Participants with non-Caucasian ethnicity, known cardiovascular disease and other conditions known to affect cardiac chamber size and function were excluded. Remaining participants formed the healthy reference cohort; reference ranges were calculated and were stratified by gender and age (45-54, 55-64, 65-74).ResultsAfter applying exclusion criteria, 804 (16.2%) participants were available for analysis. Left ventricular (LV) volumes were larger in males compared to females for absolute and indexed values. With advancing age, LV volumes were mostly smaller in both sexes. LV ejection fraction was significantly greater in females compared to males (mean?±?standard deviation [SD] of 61?±?5% vs 58?±?5%) and remained static with age for both genders. In older age groups, LV mass was lower in men, but remained virtually unchanged in women. LV mass was significantly higher in males compared to females (mean?±?SD of 53?±?9 g/m2 vs 42?±?7 g/m2). Right ventricular (RV) volumes were significantly larger in males compared to females for absolute and indexed values and were smaller with advancing age. RV ejection fraction was higher with increasing age in females only. Left atrial (LA) maximal volume and stroke volume were significantly larger in males compared to females for absolute values but not for indexed values. LA ejection fraction was similar for both sexes. Right atrial (RA) maximal volume was significantly larger in males for both absolute and indexed values, while RA ejection fraction was significantly higher in females.ConclusionsWe describe age- and sex-specific reference ranges for the left ventricle, right ventricle and atria in the largest validated normal Caucasian population.

Project description:ImportanceAdults late after total correction of tetralogy of Fallot (TOF) are at risk for major complications. Cardiovascular magnetic resonance (CMR) imaging is recommended to quantify right ventricular (RV) and left ventricular (LV) function. However, a commonly used risk model by Khairy et al requires invasive investigations and lacks CMR imaging to identify high-risk patients.ObjectiveTo implement CMR imaging in noninvasive risk stratification to predict major adverse clinical outcomes.Design, setting, and participantsThis multicenter study included 575 adult patients with TOF (4.083 patient-years at risk) from a prospective nationwide registry in whom CMR was performed. This study involved 5 tertiary referral centers with a specialized adult congenital heart disease unit. Multivariable Cox hazards regression analysis was performed to determine factors associated with the primary end point. The CMR variables were combined with the noninvasive components of the Khairy et al risk model, and the C statistic of the final noninvasive risk model was determined using bootstrap sampling. The data analysis was conducted from January to December 2016.Main outcomes and measuresThe composite primary outcome was defined as all-cause mortality or ventricular arrhythmia, defined as aborted cardiac arrest or documented ventricular fibrillation and ventricular tachycardia (lasting ≥30 seconds or recurrent symptomatic).ResultsOf the 575 patients with TOF, 57% were male, and the mean (SD) age was 31 (11) years. During a mean (SD) follow-up of 7.1 (3.5) years, the primary composite end point occurred in 35 patients, including all-cause mortality in 13 patients. Mean (SD) RV ejection fraction (EF) was 44% (10%), and mean (SD) LV EF was 53% (8%). There was a correlation between RV EF and LV EF (R, 0.36; 95% CI, 0.29-0.44; P < .001). Optimal thresholds for ventricular function (RV EF <30%: hazard ratio, 3.90; 95% CI, 1.84-8.26; P < .001 and LV EF <45%: hazard ratio, 3.23; 95% CI, 1.57-6.65; P = .001) were independently predictive in multivariable analysis. Both thresholds were included in a point-based noninvasive risk model (C statistic, 0.75; 95% CI, 0.63-0.85) and combined with the noninvasive components of the Khairy et al risk model.Conclusions and relevanceIn patients with repaired TOF, biventricular dysfunction on CMR imaging was associated with major adverse clinical outcomes. The quantified thresholds (RV EF <30% and LV EF <45%) may be implemented in noninvasive risk stratification.

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Value CMR: Towards a Comprehensive, Rapid, Cost-Effective Cardiovascular Magnetic Resonance Imaging.

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