Reference ranges ("normal values") for cardiovascular magnetic resonance (CMR) in adults and children: 2020 update.

Cardiovascular magnetic resonance (CMR) enables assessment and quantification of morphological and functional parameters of the heart, including chamber size and function, diameters of the aorta and pulmonary arteries, flow and myocardial relaxation times. Knowledge of reference ranges ("normal values") for quantitative CMR is crucial to interpretation of results and to distinguish normal from disease. Compared to the previous version of this review published in 2015, we present updated and expanded reference values for morphological and functional CMR parameters of the cardiovascular system based on the peer-reviewed literature and current CMR techniques. Further, databases and references for deep learning methods are included.

Left Ventricular Mass at MRI and Long-term Risk of Cardiovascular Events: The Multi-Ethnic Study of Atherosclerosis (MESA).

Background Few data exist on the long-term risk prediction of elevated left ventricular (LV) mass quantified by MRI for cardiovascular (CV) events in a contemporary, ethnically diverse cohort. Purpose To assess the long-term impact of elevated LV mass on CV events in a prospective cohort study of a multiethnic population in relationship to risk factors and coronary artery calcium (CAC) score. Materials and Methods The Multi-Ethnic Study of Atherosclerosis, or MESA (ClinicalTrials.gov: NCT00005487), is an ongoing prospective multicenter population-based study in the United States. A total of 6814 participants (age range, 45-84 years) free of clinical CV disease at baseline were enrolled between 2000 and 2002. In 4988 participants (2613 [52.4%] women; mean age, 62 years ± 10.1 [standard deviation]) followed over 15 years for CV events, LV mass was derived from cardiac MRI at baseline enrollment by using semiautomated software at a central core laboratory. Cox proportional hazard models, Kaplan-Meier curves, and z scores were applied to assess the impact of LV hypertrophy. Results A total of 290 participants had hard coronary heart disease (CHD) events (207 myocardial infarctions [MIs], 95 CHD deaths), 57 had other CV disease-related deaths, and 215 had heart failure (HF). LV hypertrophy was an independent predictor of hard CHD events (hazard ratio [HR]: 2.7; 95% confidence interval [CI]: 1.9, 3.8), MI (HR: 2.8; 95% CI: 1.8, 4.0), CHD death (HR: 4.3; 95% CI: 2.5, 7.3), other CV death (HR: 7.5; 95% CI: 4.2, 13.5), and HF (HR: 5.4; 95% CI: 3.8, 7.5) (P < .001 for all end points). LV hypertrophy was a stronger predictor than CAC for CHD death, other CV death, and HF (z scores: 5.4 vs 3.4, 6.8 vs 2.4, and 9.7 vs 3.2 for LV hypertrophy vs CAC, respectively). Kaplan-Meier analysis demonstrated an increased risk of CV events in participants with LV hypertrophy, particularly after 5 years. Conclusion Elevated left ventricular mass was strongly associated with hard coronary heart disease events, other cardiovascular death, and heart failure over 15 years of follow-up, independent of traditional risk factors and coronary artery calcium score. © RSNA, 2019 See also the editorial by Hanneman in this issue.

Baseline ST elevation and myocardial scar: Results from the multi-ethnic study of atherosclerosis.

BACKGROUND: The mechanism of ST elevation on baseline electrocardiograms (ECG) unknown but it may be associated with abnormal myocardial substrate. This paper evaluates whether clinically unrecognized myocardial scar on cardiac magnetic resonance imaging (CMR) is associated with ST elevation at baseline. METHODS: The Multi-Ethnic Study of Atherosclerosis (MESA) study is a population-based cohort in the United States. Participants were aged 45 through 84 years and free of clinical cardiovascular disease at enrollment in 2000-2002. Our cohort included 1365 participants who underwent both ECG and contrast enhanced CMR in the 5th examination (2010-2012). Multivariable logistic regression examined the association of ST elevation and CMR defined regional myocardial scar after adjusting for cardiovascular risk factors. RESULTS: Of 1365 participants (58 ±9 years, 52% men), 105 (8%) had scar on CMR. Of these, the scar in 40 participants followed an ischemic pattern and in the other 65 participants followed a non-ischemic pattern. ST elevation at the 5th examination was present in 435 participants: 40 (0.9%) had ST elevations in inferior and 427 (98%) in lateral leads. 2/40 (5%) and 22/427 (5%) participants with inferior and lateral ST elevations, respectively, had evidence of scar. 15 (1.0%) had myocardial scar noted in the basal anterior region. In the fully adjusted models, ST elevation was associated with scar in basal anterior region (OR 18.2, p = 0.031). CONCLUSIONS: In a community population, ST elevation at baseline in the inferior or lateral leads was associated with myocardial scar in the basal inferior and anterior segments. The previously described association between ST elevation and increased mortality may be mediated by myocardial scar.

Hypertrabeculated Left Ventricular Myocardium in Relationship to Myocardial Function and Fibrosis: The Multi-Ethnic Study of Atherosclerosis.

Purpose To determine if excess greater left ventricle (LV) trabeculation is associated with decreased average regional myocardial function, diffuse fibrosis, or both. Materials and Methods This was a HIPAA-compliant institutional board approved multicenter study, and all participants provided written informed consent. Participants in the Multi-Ethnic Study of Atherosclerosis (MESA) underwent a comprehensive cardiac magnetic resonance (MR) examination. LV trabeculation was measured with the maximal apical fractal dimension (FD), which is a marker of endocardial complexity. Demographic covariates, cardiovascular risk factors, and cardiac MR measurements were compared across quartiles of FD. Associations between FD and peak regional systolic circumferential strain (Ecc) and T1 time, a surrogate for diffuse myocardial fibrosis, were assessed with multivariable linear regression models. Results A total of 1123 subjects (593 [52.8%] female; mean age, 67.1 years ± 8.7 [standard deviation]) underwent FD and Ecc measurement, and 992 (521 [52.5%] female; mean age, 67.1 years ± 8.7) underwent FD and T1 measurement. Mean FD was 1.2 ± 0.07 in both groups, and mean Ecc was -18.3 ± 2.27 in the subjects who underwent FD and Ecc measurement. Global volumes and ejection fraction showed no differences between FD quartiles. However, with increasing FD quartile, Ecc was greater (indicating worse average regional function) (P < .001). After adjustment, greater trabeculation was associated with 21% worse myocardial strain (relative to the mean) per unit change in FD (regression coefficient = 4.0%; P < .001). There was no association between the degree of trabeculation and diffuse fibrosis measured with T1 mapping. Conclusion Average regional LV function was worse in individuals with greater LV trabeculation, supporting the concept of hypertrabeculation being an epiphenomenon of disease. © RSNA, 2017.

Fractal Analysis of Myocardial Trabeculations in 2547 Study Participants: Multi-Ethnic Study of Atherosclerosis.

PURPOSE: To quantitatively determine the population variation and relationship of left ventricular (LV) trabeculation to LV function, structure, and clinical variables. MATERIALS AND METHODS: This HIPAA-compliant multicenter study was approved by institutional review boards of participating centers. All participants provided written informed consent. Participants from the Multi-Ethnic Study of Atherosclerosis with cardiac magnetic resonance (MR) data were evaluated to quantify LV trabeculation as a fractal dimension (FD). Entire cohort participants free of cardiac disease, hypertrophy, hypertension, and diabetes were stratified by body mass index (BMI) into three reference groups (BMI <25 kg/m(2); BMI ≥25 kg/m(2) to <30 kg/m(2); and BMI ≥30 kg/m(2)) to explore maximal apical FD (FDMaxApical). Multivariable linear regression models determined the relationship between FD and other parameters. RESULTS: Included were 2547 participants (mean age, 68.7 years ± 9.1 [standard deviation]; 1211 men). FDMaxApical are in arbitrary units. FDMaxApical reference ranges for BMI 30 kg/m(2) or greater (n = 163), 25 kg/m(2) or greater to less than 30 kg/m(2) (n = 206), and less than 25 kg/m(2) (n = 235) were 1.203 ± 0.06 (95% confidence interval: 1.194, 1.212), 1.194 ± 0.06 (95% confidence interval: 1.186, 1.202), and 1.169 ± 0.05 (95% confidence interval: 1.162, 1.176), respectively. In the entire cohort, adjusted for anthropometrics, trabeculation was higher in African American participants (standardized ß [sß] = 0.09; P ≤ .001) and Hispanic participants (sß = 0.05; P = .013) compared with white participants and was also higher in African American participants compared with Chinese American participants (sß = 0.08; P = .01), and this persisted after adjustment for hypertension and LV size. Hypertension (sß = 0.07; P < .001), LV mass (sß = 0.22; P < .001), and wall thickness (sß = 0.27; P < .001) were positively associated with FDMaxApical even after adjustment. In the group with BMIs less than 25 kg/m(2), Chinese American participants had less trabeculation than white participants (sß = -0.15; P = .032). CONCLUSION: Fractal analysis of cardiac MR imaging data measures endocardial complexity, which helps to differentiate normal from abnormal trabecular patterns in healthy versus diseased hearts. Trabeculation is influenced by race and/or ethnicity and, more importantly, by cardiac loading conditions and comorbidities. Clinicians who interpret cine MR imaging data should expect slightly less endocardial complexity in Chinese American patients and more in African American patients, Hispanic patients, hypertensive patients, and those with hypertrophy.

Normal values for cardiovascular magnetic resonance in adults and children.

Morphological and functional parameters such as chamber size and function, aortic diameters and distensibility, flow and T1 and T2* relaxation time can be assessed and quantified by cardiovascular magnetic resonance (CMR). Knowledge of normal values for quantitative CMR is crucial to interpretation of results and to distinguish normal from disease. In this review, we present normal reference values for morphological and functional CMR parameters of the cardiovascular system based on the peer-reviewed literature and current CMR techniques and sequences.

Artificial intelligence (AI)-assisted chest computer tomography (CT) insights: a study on intensive care unit (ICU) admittance trends in 78 coronavirus disease 2019 (COVID-19) patients.

Background: The global coronavirus disease 2019 (COVID-19) pandemic has posed substantial challenges for healthcare systems, notably the increased demand for chest computed tomography (CT) scans, which lack automated analysis. Our study addresses this by utilizing artificial intelligence-supported automated computer analysis to investigate lung involvement distribution and extent in COVID-19 patients. Additionally, we explore the association between lung involvement and intensive care unit (ICU) admission, while also comparing computer analysis performance with expert radiologists' assessments. Methods: A total of 81 patients from an open-source COVID database with confirmed COVID-19 infection were included in the study. Three patients were excluded. Lung involvement was assessed in 78 patients using CT scans, and the extent of infiltration and collapse was quantified across various lung lobes and regions. The associations between lung involvement and ICU admission were analysed. Additionally, the computer analysis of COVID-19 involvement was compared against a human rating provided by radiological experts. Results: The results showed a higher degree of infiltration and collapse in the lower lobes compared to the upper lobes (P<0.05). No significant difference was detected in the COVID-19-related involvement of the left and right lower lobes. The right middle lobe demonstrated lower involvement compared to the right lower lobes (P<0.05). When examining the regions, significantly more COVID-19 involvement was found when comparing the posterior vs. the anterior halves and the lower vs. the upper half of the lungs. Patients, who required ICU admission during their treatment exhibited significantly higher COVID-19 involvement in their lung parenchyma according to computer analysis, compared to patients who remained in general wards. Patients with more than 40% COVID-19 involvement were almost exclusively treated in intensive care. A high correlation was observed between computer detection of COVID-19 affections and the rating by radiological experts. Conclusions: The findings suggest that the extent of lung involvement, particularly in the lower lobes, dorsal lungs, and lower half of the lungs, may be associated with the need for ICU admission in patients with COVID-19. Computer analysis showed a high correlation with expert rating, highlighting its potential utility in clinical settings for assessing lung involvement. This information may help guide clinical decision-making and resource allocation during ongoing or future pandemics. Further studies with larger sample sizes are warranted to validate these findings.

Modified look-locker inversion recovery T1 mapping indices: assessment of accuracy and reproducibility between magnetic resonance scanners.

BACKGROUND: Cardiovascular magnetic resonance (CMR) T1 mapping indices, such as T1 time and partition coefficient (λ), have shown potential to assess diffuse myocardial fibrosis. The purpose of this study was to investigate how scanner and field strength variation affect the accuracy and precision/reproducibility of T1 mapping indices. METHODS: CMR studies were performed on two 1.5T and three 3T scanners. Eight phantoms were made to mimic the T1/T2 of pre- and post-contrast myocardium and blood at 1.5T and 3T. T1 mapping using MOLLI was performed with simulated heart rate of 40-100 bpm. Inversion recovery spin echo (IR-SE) was the reference standard for T1 determination. Accuracy was defined as the percent error between MOLLI and IR-SE, and scan/re-scan reproducibility was defined as the relative percent mean difference between repeat MOLLI scans. Partition coefficient was estimated by ΔR1myocardium phantom/ΔR1blood phantom. Generalized linear mixed model was used to compare the accuracy and precision/reproducibility of T1 and λ across field strength, scanners, and protocols. RESULTS: Field strength significantly affected MOLLI T1 accuracy (6.3% error for 1.5T vs. 10.8% error for 3T, p<0.001) but not λ accuracy (8.8% error for 1.5T vs. 8.0% error for 3T, p=0.11). Partition coefficients of MOLLI were not different between two 1.5T scanners (47.2% vs. 47.9%, p=0.13), and showed only slight variation across three 3T scanners (49.2% vs. 49.8% vs. 49.9%, p=0.016). Partition coefficient also had significantly lower percent error for precision (better scan/re-scan reproducibility) than measurement of individual T1 values (3.6% for λ vs. 4.3%-4.8% for T1 values, approximately, for pre/post blood and myocardium values). CONCLUSION: Based on phantom studies, T1 errors using MOLLI ranged from 6-14% across various MR scanners while errors for partition coefficient were less (6-10%). Compared with absolute T1 times, partition coefficient showed less variability across platforms and field strengths as well as higher precision.

Cardiovascular Magnetic Resonance for Patients With COVID-19.

COVID-19 is associated with myocardial injury caused by ischemia, inflammation, or myocarditis. Cardiovascular magnetic resonance (CMR) is the noninvasive reference standard for cardiac function, structure, and tissue composition. CMR is a potentially valuable diagnostic tool in patients with COVID-19 presenting with myocardial injury and evidence of cardiac dysfunction. Although COVID-19-related myocarditis is likely infrequent, COVID-19-related cardiovascular histopathology findings have been reported in up to 48% of patients, raising the concern for long-term myocardial injury. Studies to date report CMR abnormalities in 26% to 60% of hospitalized patients who have recovered from COVID-19, including functional impairment, myocardial tissue abnormalities, late gadolinium enhancement, or pericardial abnormalities. In athletes post-COVID-19, CMR has detected myocarditis-like abnormalities. In children, multisystem inflammatory syndrome may occur 2 to 6 weeks after infection; associated myocarditis and coronary artery aneurysms are evaluable by CMR. At this time, our understanding of COVID-19-related cardiovascular involvement is incomplete, and multiple studies are planned to evaluate patients with COVID-19 using CMR. In this review, we summarize existing studies of CMR for patients with COVID-19 and present ongoing research. We also provide recommendations for clinical use of CMR for patients with acute symptoms or who are recovering from COVID-19.

Association of Pro-B-Type Natriuretic Peptide With Cardiac Magnetic Resonance-Measured Global and Regional Cardiac Function and Structure Over 10 Years: The MESA Study.

Background NT-proBNP (N-terminal pro-B-type natriuretic peptide) is widely used to diagnose and manage patients with heart failure. We aimed to investigate associations between NT-proBNP levels and development of global and regional myocardial impairment, dyssynchrony, and risk of developing myocardial scar over time. Methods and Results We included 2416 adults (45-84 years) without baseline clinical cardiovascular disease from MESA (Multi-Ethnic Study of Atherosclerosis). NT-proBNP was assessed at baseline (2000-2002). Cardiac magnetic resonance-measured left ventricular parameters were assessed at baseline and year 10 (2010-2012). Tagged cardiac magnetic resonance and myocardial dyssynchrony were assessed. We used linear and logistic regression models to study the relationships between quartiles of NT-proBNP levels and outcome variables. Left ventricular parameters decreased over time. After 10-year follow-up and adjusting for cardiovascular disease risk factors, people in the highest quartile had significantly greater decline in left ventricular ejection fraction (-1.60%; 95% CI, -2.26 to -0.94; P<0.01) and smaller decline in left ventricular end systolic volume index (-0.47 mL/m2; 95% CI, -1.18 to 0.23; P<0.01) compared with those in the lowest quartile. Individuals in the highest quartile had more severe risk factor adjusted global, mid, and apical regional dyssynchrony compared with those in the lowest, second, and third quartiles (all P-trend<0.05). Compared with the lowest-quartile group, the adjusted odds ratios for having myocardial scar was 1.3 (95% CI, 0.7-2.2) for quartile 2; 1.2 (95% CI, 0.6-2.3) for quartile 3; and 2.7 (95% CI, 1.4-5.5) for quartile 4 (P-trend=0.012) for the total sample. Conclusions Among participants without baseline clinical cardiovascular disease, higher baseline NT-proBNP concentration was significantly associated with subclinical changes in developing myocardial dysfunction, more severe cardiac dyssynchrony, and higher odds of having myocardial scar over a 10-year period independent of traditional cardiovascular disease risk factors.

Prevalence of Unexplained Left Ventricular Hypertrophy by Cardiac Magnetic Resonance Imaging in MESA.

Background Hypertrophic cardiomyopathy is defined as unexplained left ventricular ( LV ) hypertrophy (wall thickness ≥15 mm) and is prevalent in 0.2% of adults (1:500) in population-based studies using echocardiography. Cardiac magnetic resonance imaging ( MRI ) allows for more accurate wall thickness measurement across the entire ventricle than echocardiography. The prevalence of unexplained LV hypertrophy by cardiac MRI is unknown. MESA (Multi-Ethnic Study of Atherosclerosis) recruited individuals without overt cardiovascular disease 45 to 84 years of age. Methods and Results We studied 4972 individuals who underwent measurement of regional LV wall thickness by cardiac MRI as part of the MESA baseline exam. American Heart Association criteria were used to define LV segments. We excluded participants with hypertension, LV dilation (≥95% predicted end-diastolic volume) or dysfunction (ejection fraction ≤50%), moderate-to-severe left-sided valve lesions by cardiac MRI , severe aortic valve calcification by cardiac computed tomography (aortic valve Agatston calcium score >1200 in women or >2000 in men), obesity (body mass index >35 kg/m2), diabetes mellitus, and current smoking. Sixty-seven participants (aged 64±10 years, 9% female) had unexplained LV hypertrophy (wall thickness ≥15 mm in at least 2 adjacent LV segments), representing 1.4% (1 in 74) participants, 2.6% of men and 0.2% of women. Prevalence was similar across categories of race/ethnicity. Hypertrophy was focal in 17 (25.4%), intermediate in 44 (65.7%), and diffuse in 5 (7.5%) participants. Conclusions The prevalence of unexplained LV hypertrophy in a population-based cohort using cardiac MRI was 1.4%. This may have implications for the diagnosis of patients with hypertrophic cardiomyopathy and will require further study.

Subspecialized Radiological Reporting Expedites Turnaround Time of Radiology Reports and Increases Productivity.

INTRODUCTION: To assess the impact of changing from general to subspecialized reporting on turnaround time of radiology reports (TAT), the fraction of radiology reports available within 24 hours (R< 24 h) and productivity. MATERIALS AND METHODS: Reporting workflow in our radiology department was changed from general reporting (radiologists report imaging studies of all areas [neuroradiological, abdominal, musculoskeletal imaging et cetera]) to subspecialized reporting (radiologists solely report imaging studies of their subspecialty field [e. g. musculoskeletal]). TAT, R< 24 h and productivity were calculated for a 12-month period of general reporting (January-December 2012) and compared to a 12-month period of subspecialized reporting (April 2014-March 2015) using Mann Whitney U-test, Pearson chi-square test and odds ratios, respectively. RESULTS: Report TAT decreased from a median of 17:04 hours (h) during general reporting to 3:38 h during subspecialized reporting, resulting in a 4.7-fold improvement (p < 0.001). R< 24 h improved significantly from 65 % to 87 % (p < 0.001). The odds of a radiology report being available < 24 h was 3.6- fold higher during subspecialized compared to general reporting. Productivity increased from a median of 301 to 376 (reports/full-time radiologist/month) (p = 0.001). CONCLUSION: Changing the workflow from general to subspecialized reporting significantly improved the turnaround time of radiology reports, the fraction of radiology reports available within 24 hours and productivity. KEY POINTS: · Changing the radiology reporting workflow from general to subspecialized reporting is feasible.. · Implementation of subspecialized reporting yielded significant improvement of radiology report turnaround time.. · Implementation of subspecialized reporting substantially increased the fraction of radiology reports available < 24 h.. · Radiologists' productivity increased after changing to subspecialized reporting.. CITATION FORMAT: · Stern C, Boehm T, Seifert B et al. Subspecialized Radiological Reporting Expedites Turnaround Time of Radiology Reports and Increases Productivity. Fortschr Röntgenstr 2018; 190: 623 - 629.

Absence of Fibrosis and Inflammation by Cardiac Magnetic Resonance Imaging in Rheumatoid Arthritis Patients with Low to Moderate Disease Activity.

OBJECTIVE: The prevalence of heart failure is increased 2-fold in patients with rheumatoid arthritis (RA); this is not explained by ischemic heart disease or other risk factors for heart failure. We hypothesized that in patients with RA without known heart disease, cardiac magnetic resonance imaging (cMRI) would detect altered cardiac structure, function, and fibrosis. METHODS: We performed 1.5-T cMRI in 59 patients with RA and 56 controls frequency-matched for age, race, and sex, and compared cMRI indices of structure, function, and fibrosis [late gadolinium enhancement (LGE), native T1 mapping, and extracellular volume (ECV)] using Mann-Whitney U tests and linear regression, adjusting for age, race, and sex. RESULTS: Most patients with RA had low to moderate disease activity [28-joint count Disease Activity Score-C-reactive protein median 3.16, interquartile range (IQR) 2.03-4.05], and 49% were receiving anti-tumor necrosis factor agents. Left ventricular (LV) mass, LV end-diastolic and -systolic volumes indexed to body surface area, and LV ejection fraction and left atrial size were not altered in RA compared to controls (all p > 0.05). Measures of fibrosis were not increased in RA: LGE was present in 2 patients with RA and 1 control subject; native T1 mapping was similar comparing RA and control subjects, and ECV (median, IQR) was lower (26.6%, 24.7-28.5%) in patients with RA compared to control subjects (27.5%, 25.4-30.4%, p = 0.03). CONCLUSION: cMRI measures of cardiac structure and function were not significantly altered, and measures of fibrosis were similar or lower in RA patients with low to moderate disease activity compared to a matched control group.

Cardiovascular imaging environment: will the future be cloud-based?

INTRODUCTION: In cardiovascular CT and MR imaging large datasets have to be stored, post-processed, analyzed and distributed. Beside basic assessment of volume and function in cardiac magnetic resonance imaging e.g., more sophisticated quantitative analysis is requested requiring specific software. Several institutions cannot afford various types of software and provide expertise to perform sophisticated analysis. Areas covered: Various cloud services exist related to data storage and analysis specifically for cardiovascular CT and MR imaging. Instead of on-site data storage, cloud providers offer flexible storage services on a pay-per-use basis. To avoid purchase and maintenance of specialized software for cardiovascular image analysis, e.g. to assess myocardial iron overload, MR 4D flow and fractional flow reserve, evaluation can be performed with cloud based software by the consumer or complete analysis is performed by the cloud provider. However, challenges to widespread implementation of cloud services include regulatory issues regarding patient privacy and data security. Expert commentary: If patient privacy and data security is guaranteed cloud imaging is a valuable option to cope with storage of large image datasets and offer sophisticated cardiovascular image analysis for institutions of all sizes.