Optimized Three-Dimensional Cardiovascular Magnetic Resonance Whole Heart Imaging Utilizing Non-Selective Excitation and Compressed Sensing in Children and Adults with Congenital Heart Disease

Background:In congenital heart disease(CHD)patients,detailed three-dimensional anatomy depiction plays a pivotal role for diagnosis and therapeutical decision making.Hence,the present study investigated the applicability of an advanced cardiovascular magnetic resonance(CMR)whole heart imaging approach utilizing nonselective excitation and compressed sensing for anatomical assessment and interventional guidance of CHD patients in comparison to conventional dynamic CMR angiography.Methods:86 consecutive pediatric patients and adults with congenital heart disease(age,1 to 74 years;mean,35 years)underwent CMR imaging including a freebreathing,ECG-triggered 3D nonselective SSFP whole heart acquisition using compressed SENSE(nsWHcs).Anatomical assessability and signal intensity ratio(SIR)measurements were compared with conventional dynamic 3D-/4D-MR angiography.Results:The most frequent diagnoses were partial anomalous pulmonary venous drainage(17/86,20%),transposition of the great arteries(15/86,17%),tetralogy of Fallot(12/86,14%),and a single ventricle(7/86,8%).Image quality of nsWHcs was rated as excellent/good in 98%of patients.nsWHcs resulted in a reliable depiction of all large thoracic vessels(anatomic assessability,99%–100%)and the proximal segments of coronary arteries and coronary sinus(>90%).nsWHcs achieved a homogenously distributed SIR in all cardiac cavities and thoracic vessels without a significant difference between pulmonary and systemic circulation(10.9±3.5 and 10.6±3.4;p=0.15),while 3D angiography showed significantly increased SIR for targeted vs.non-targeted circulation(PA-angiography,15.2±8.1 vs.5.8±3.6,p<0.001;PV-angiography,7.0±3.9 vs.17.3±6.8,p<0.001).Conclusions:The proposed nsWHcs imaging approach provided a consistently high image quality and a homogeneous signal intensity distribution within the pulmonary and systemic circulation in pediatric patients and adults with a wide spectrum of congenital heart diseases.nsWHcs enabled detailed anatomical assessment and three-dimensional reconstruction of all cardiac cavities and large thoracic vessels and can be regarded particularly useful for preprocedural planning and interventional guidance in CHD patients.

Cardiovascular magnetic resonance in myocardial infarction with non-obstructive coronary arteries patients: A review

The diagnosis of myocardial infarction with non-obstructive coronary arteries(MINOCA)necessitates documentation of an acute myocardial infarction(AMI),non-obstructive coronary arteries,using invasive coronary angiography or coronary computed tomography angiography and no clinically overt cause for AMI.Historically patients with MINOCA represent a clinical dilemma with subsequent uncertain clinical management.Differential diagnosis is crucial to choose the best therapeutic option for ischemic and non-ischemic MINOCA patients.Cardiovascular magnetic resonance(CMR)is able to analyze cardiac structure and function simultaneously and provides tissue characterization.Moreover,CMR could identify the cause of MINOCA in nearly two-third of patients providing valuable information for clinical decision making.Finally,it allows stratification of patients with worse outcomes which resulted in therapeutic changes in almost half of the patients.In this review we discuss the features of CMR in MINOCA;from exam protocols to imaging findings.

Frontiers of COVID-19-related myocarditis as assessed by cardiovascular magnetic resonance

Coronavirus disease 2019(COVID-19)is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection.In some patients,COVID-19 is complicated with myocarditis.Early detection of myocardial injury and timely intervention can significantly improve the clinical outcomes of COVID-19 patients.Although endomyocardial biopsy(EMB)is currently recognized as the‘gold standard’for the diagnosis of myocarditis,there are large sampling errors,many complications and a lack of unified diagnostic criteria.In addition,the clinical methods of treating acute and chronic COVID-19-related myocarditis are different.Cardiac magnetic resonance(CMR)can evaluate the morphology of the heart,left and right ventricular functions,myocardial perfusion,capillary leakage and myocardial interstitial fibrosis to provide a noninvasive and radiation-free diagnostic basis for the clinical detection,efficacy and risk assessment,and followup observation of COVID-19-related myocarditis.However,for the diagnosis of COVID-19-related myocarditis,the Lake Louise Consensus Criteria may not be fully applicable.COVID-19-related myocarditis is different from myocarditis related to other viral infections in terms of signal intensity and lesion location as assessed by CMR,which is used to visualize myocardial damage,locate lesions and quantify pathological changes based on various sequences.Therefore,the standardized application of CMR to timely and accurately evaluate heart injury in COVID-19-related myocarditis and develop rational treatment strategies could be quite effective in improving the prognosis of patients and preventing potential late-onset effects in convalescent patients with COVID-19.

Feature-Tracking Strain Derived from Compressed Sensing Cine Cardiovascular Magnetic Resonance Imaging for Myocardial Infarct Detection: A Feasibility Study

Purpose: This study aimed to use gadolinium-enhanced cardiovascular magnetic resonance (LGE-CMR) scanning to examine the clinical feasibility of feature-tracking strain (FT-strain) analysis on compressed sensing (CS) cine cardiovascular magnetic resonance (CMR) imaging for detecting myocardial infarction (MI). Methods: We enrolled 37 patients who underwent conventional cine CMR, CS cine CMR, and LGE-CMR scanning to assess cardiovascular disease. FT-strain analysis was used to assess peak circumferential strain (p-CS) based on an 18-segment model in both cine CMR imaging modalities. Based on LGE-CMR imaging findings, myocardial segments were classified as remote, adjacent, subendocardial infarcted, and transmural infarcted. The diagnostic performance of p-CS for detecting MI was compared between CS cine CMR imaging and conventional cine CMR imaging using the receiver operating characteristic (ROC) curve analysis. Results: A total of 440 remote, 85 adjacent, 76 subendocardial infarcted, and 65 transmural infarcted segments were diagnosed on LGE-CMR imaging. There were significant between-group differences in p-CS on both conventional and CS cine CMR (p < 0.05 in each) imaging. The sensitivity and specificity of p-CS for identifying MI were 85% and 79% for conventional cine CMR imaging, and 82% and 77% for CS cine CMR imaging, respectively. There was no significant difference between conventional and CS cine CMR imaging in the area under the curve of p-CS (0.89 vs. 0.87, p = 0.15). Conclusion: FT-strain analysis of CS cine CMR imaging may help identify MI;it may be used alongside or instead of conventional CMR imaging.

Role of cardiac magnetic resonance imaging in the diagnosis and management of COVID-19 related myocarditis: Clinical and imaging considerations

There is a growing evidence of cardiovascular complications in coronavirusdisease 2019 (COVID-19) patients. As evidence accumulated of COVID-19 mediatedinflammatory effects on the myocardium, substantial attention has beendirected towards cardiovascular imaging modalities that facilitate this diagnosis.Cardiac magnetic resonance imaging (CMRI) is the gold standard for thedetection of structural and functional myocardial alterations and its role inidentifying patients with COVID-19 mediated cardiac injury is growing. Despiteits utility in the diagnosis of myocardial injury in this population, CMRI’s impacton patient management is still evolving. This review provides a framework for theuse of CMRI in diagnosis and management of COVID-19 patients from theperspective of a cardiologist. We review the role of CMRI in the management ofboth the acutely and remotely COVID-19 infected patient. We discuss patientselection for this imaging modality;T1, T2, and late gadolinium enhancementimaging techniques;and previously described CMRI findings in other cardiomyopathieswith potential implications in COVID-19 recovered patients.

Left atrial physiology and pathophysiology:Role of deformation imaging

The left atrium(LA) acts as a modulator of left ventricular(LV) filling. Although there is considerable evidence to support the use of LA maximum and minimum volumes for disease prediction,theoretical considerations and a growing body of literature suggest to focus on the quantification of the three basic LA functions:(1) Reservoir function:collection of pulmonary venous return during LV systole;(2) Conduit function:passage of blood to the left ventricle during early LV diastole; and(3) Contractile booster pump function(augmentation of ventricular filling during late LV diastole. Tremendous advances in our ability to non-invasively characterize all three elements of atrial function include speckle tracking echocardiography(STE),and more recently cardiovascular magnetic resonance myocardial feature tracking(CMR-FT). Corresponding imaging biomarkers are increasingly recognized to have incremental roles in determining prognosis and risk stratification in cardiac dysfunction of different origins. The current editorial introduces the role of STE and CMR-FT for the functional assessment of LA deformation as determined by strain and strain rate imaging and provides an outlook of how this exciting field may develop in the future.

The Impact of a Bicuspid Aortic Valve on Aortic Geometry and Function in Patients with Aortic Coarctation:A Comprehensive CMR Study

Background:An isolated bicuspid aortic valve(BAV)is associated with structural and functional abnormalities of the aorta and the left ventricle(LV).Although~50%of patients with aortic coarctation(CoA)have a BAV,less is known about its impact on LV function and aortic geometry and function in CoA patients.In this cardiovascular magnetic resonance imaging(CMR)study,we analysed markers of LV and aortic function as well as aortic geometry in a large cohort of CoA patients with a BAVand compared them with CoA patients with a tricuspid aortic valve(TAV).Methods:We included 48 patients with a BAV(18.4±9.3 years)and 45 patients with TAV(20.7±9.9 years).LV volumes,mass and ejection fraction as well as aortic distensibilty,pulse wave velocity(PWV)were measured from standard cine CMR and phase-contrast CMR images.2-dimensional CMR feature tracking(2DCMR-FT)was performed to measure longitudinal,circumferential and radial strain and strain rate of the LV.Aortic arch geometry was classified as romanic,gothic and crenel.Results:LV volumes,mass and ejection fraction as well as aortic distensibility and PWV did not significantly differ between the BAV and the TAV group.There was also no significant difference for LV global longitudinal,radial and circumferential strain and strain rate between both groups.Patients with a BAV had more commonly a gothic aortic arch compared to TAV patients,but this difference was not statistically significant(22 vs.14,p=0.2).Ascending and descending aortic distensibility correlated with LV mass in the entire patient group(p<0.001).Global longitudinal,circumferential and radial strain(GLS,GCS,GRS)and global longitudinal and circumferential strain rate(GLSR,GCSR)correlated with LV ejection fraction(p<0.001).Conclusion:Our data suggest that the presence of a BAV does not adversely impact LV and aortic function in children and young adults with CoA.The correlation of global circumferential,longitudinal and radial strain values with LV ejection fraction demonstrates that 2D-CMR-FT might provide additional information related to ventricular function in CoA patients.

A Ring-Reinforced Right Ventricle to Pulmonary Artery Conduit Is Associated with Better Regional Mechanics after Stage I Norwood Operation

Background:The right ventricle to pulmonary artery conduit(RVPAC)may impair right ventricular(RV)function in patients with functional single right ventricles.Modification of the RVPAC using a ring-reinforced end with dunked insertion into the RV through a limited ventriculotomy may reduce the impact on RV function.We compared RV segmental strain between patients with a traditional RVPAC and ring-reinforced RVPAC using feature tracking cardiovascular magnetic resonance(CMR)imaging.Methods:Patients with CMR examinations after Stage I operation with RVPAC between 2000 and 2018 were reviewed.Ventricular mass,volumes,late gadolinium enhancement(LGE),and peak radial and circumferential strain of the 4 segments near the RVPAC insertion site were analyzed.Results:The study included 71 CMR examinations in 61 patients(30 traditional RVPAC,31 ring-reinforced RVPAC).Prior to Stage II,the ring-reinforced RVPAC group had better peak radial strain and circumferential strain in 1 of 4 segments proximal to the RVPAC insertion site compared to the traditional RVPAC group.Prior to Stage III operation,the ring-reinforced group had better peak radial and circumferential strain in 2 of 4 segments.LGE at the RVPAC insertion site was observed in 97%of patients before Stage II and 95%of patients before Stage III.RVPAC type and regional strain were not associated with transplant-free survival during a median follow-up of 6.3 years.Conclusions:Compared to a traditional RVPAC,the ring-reinforced RVPAC is associated with improved regional mechanics at the conduit insertion site.Further investigation of long-term outcomes after ring-reinforced RVPAC is warranted.

Automated Segmentation of Left Ventricle Using Local and Global Intensity Based Active Contour and Dynamic Programming

The aim of this work is to develop an improved region based active contour and dynamic programming based method for accurate segmentation of left ventricle （LV） from multi-slice cine short axis cardiac magnetic resonance （MR） images. Intensity inhomogeneity and weak object boundaries present in MR images hinder the segmentation accuracy. The proposed active contour model driven by a local Gaussian distribution fitting （LGDF） energy and an auxiliary global intensity fitting energy improves the accuracy of endocardial boundary detection. The weightage of the global energy fitting term is dynamically adjusted using a spatially varying weight function. Dynamic programming scheme proposed for the segmentation of epicardium considers the myocardium probability map and a distance weighted edge map in the cost matrix. Radial distance weighted technique and conical geometry are employed for segmenting the basal slices with left ventricle outflow tract （LVOT） and most apical slices. The proposed method is validated on a public dataset comprising 45 subjects from medical image computing and computer assisted interventions （MICCAI） 2009 segmentation challenge. The average percentage of good endocardial and epicardial contours detected is about 99%, average perpendicular distance of the detected good contours from the manual reference contours is 1.95 mm, and the dice similarity coefficient between the detected contours and the reference contours is 0.91. Correlation coefficient and the coefficient of determination between the ejection fraction measurements from manual segmentation and the automated method are respectively 0.9781 and 0.9567, for LV mass these values are 0.9249 and 0.8554. Statistical analysis of the results reveals a good agreement between the clinical parameters determined manually and those estimated using the automated method.