Advances in cardiac imaging: the role of magnetic resonance imaging and computed tomography in identifying athletes at risk

Cardiodiagnostic sex-specific differences of the female athlete in sports cardiology

The cardiovascular care of highly active individuals and competitive athletes has developed into an important focus within the field of sports medicine. An evolving understanding of exercise-induced cardiovascular remodeling in athletes has led to a more robust characterization of physiologic adaptation versus pathological dysfunction, but this distinction is often challenging due to diagnostic commonalities. Current data reflects sporting-focused analyses of mainly male athletes, which may not be easily applicable to the female athletic heart. Increasingly female-specific cardiac dimensional and physiologic data are starting to emerge from comparative studies that may be utilized to address this growing need, and further guide individualized care. Here, we review current literature evaluating female-specific cardiovascular adaptations of the athletic heart, and formulate a discussion on cardiac remodeling, cardiodiagnostic findings, etiologic mechanisms, limitations of currently available data, and direction for future research in the cardiovascular care of female athletes.

The role of cardiac computed tomography in sports cardiology: back to the future!

In recent years, the role of pre-participation evaluation (PPE) in the prevention of sudden cardiac death in competitive athletes has become evident. Most physicians routinely supplement assessment by resting electrocardiogram with imaging techniques, such as echocardiography. The primary goal of imaging in the clinical assessment of competitive athletes is to exclude cardiovascular conditions associated with adverse outcomes. Cardiac computed tomography is emerging as an important technique for stratifying cardiovascular risk and assessing coronary artery disease (CAD), particularly in master athletes. Conversely, in young athletes, this technique has the best non-invasive coronary artery resolution and provides valuable details on coronary artery anatomy. Recent technical developments have brought about a dramatic reduction in radiation exposure, a major drawback of this diagnostic method; nowadays cardiac computed tomography may be performed at a dose of barely one millisievert. The present review provides a practical guide for the use of cardiac computed tomography in the PPE of competitive athletes, with a specific focus on its value for detecting congenital coronary anomalies and CAD in young and master athletes, respectively.

Cardiac Magnetic Resonance Normal Reference Values of Biventricular Size and Function in Male Athlete's Heart

OBJECTIVES

The aim of this meta-analysis was to derive normal reference values of biventricular size and function estimated by cardiac magnetic resonance (CMR) in competitive athletes.

BACKGROUND

Exercise-induced enlargement of cardiac chambers is commonly observed in competitive athletes. However, ventricular dilatation is also a common phenotypic expression of life-threatening cardiomyopathies. The use of CMR for the exclusion of pathology is growing. However, normal reference values have not been established for athletes.

METHODS

The authors conducted a systematic review of English-language studies in the MEDLINE, Scopus, and Cochrane databases investigating biventricular size and function by CMR in athletes. Athletes were divided into endurance, combined, and mixed groups according to the sport practiced. The potential impact of training volume was also evaluated.

RESULTS

Twenty-seven studies and 983 competitive athletes were included for CMR quantification of biventricular size and function. In this review, normal reference values are presented for biventricular size and function to be applied to male competitive athletes according to the disciplines practiced. A significant impact of training volume was demonstrated for the right ventricle: athletes practicing the largest number of training hours per week were those exhibiting the greatest degree of right ventricular remodeling. Notably, biventricular function was not significantly affected by training volume.

CONCLUSIONS

The present meta-analysis defines the normal limits of biventricular size and function estimated by CMR in competitive athletes. The authors suggest using these normal reference values as an alternative to standard upper limits derived from the general population when interpreting CMR images in athletes.

High-Risk Cardiovascular Conditions in Sports-Related Sudden Death: Prevalence in 5,169 Schoolchildren Screened via Cardiac Magnetic Resonance

Improving preparticipation screening of candidates for sports necessitates establishing the prevalence of high-risk cardiovascular conditions (hr-CVC) that predispose young people to sudden cardiac death (SCD). Our accurate, novel protocol chiefly involved the use of cardiac magnetic resonance (CMR) to estimate this prevalence. Middle and high school students from a general United States population were screened by means of questionnaires, resting electrocardiograms, and CMR to determine the prevalence of 3 types of hr-CVC: electrocardiographic abnormalities, cardiomyopathies, and anomalous coronary artery origin from the opposite sinus with intramural coronary course (ACAOS-IM). We examined the range of normal left ventricular size and function in the main study cohort (schoolchildren 11-14 yr old). We defined diagnostic criteria for hr-CVC and compared the cardiac measurements of these younger participants with those of older children whom we examined (age, 15-18 yr). From 5,169 completed diagnostic studies (mean participant age, 13.06 ± 1.78 yr), CMR results revealed 76 previously undiagnosed cases of hr-CVC (1.47% of the total cohort): 11 of dilated cardiomyopathy (14.5%), 3 of nonobstructive hypertrophic cardiomyopathy (3.9%), 23 ACAOS-IM cases (30.3%; 6 left-ACAOS and 17 right-ACAOS), 4 Wolff-Parkinson-White patterns (5.3%), 34 prolonged QT intervals (44.7%), and 1 Brugada pattern (1.3%). Cardiomyopathies were significantly more prevalent in the older children. Of note, we identified 959 cases (18.5%) of left ventricular noncompaction. If our estimate is accurate, only 1.47% of school-age sports participants will need focused secondary evaluations; the rest can probably be reassured about their cardiac health after one 30-minute screening study.

Clinical significance of ST depression at exercise stress testing in competitive athletes: usefulness of coronary CT during screening

BACKGROUND

Congenital coronary anomalies (CCAs) and coronary artery disease (CAD) arouse intense scientific and clinical interest in sports medicine and sports cardiology medical communities because of their potential to trigger sudden cardiac death (SCD) in athletes. Exercise stress testing represent the first instrumental assessment to evaluate electrocardiographic changes during effort. Coronary computed tomography angiography (CCTA) is an advanced accurate noninvasive imaging modality for excluding CAD and abnormalities of origin and course of coronary vessels. The aim of this study is to investigate with CCTA the clinical significance of ST depression suggestive for myocardial ischemia during exercise stress testing in athletes and to determine the prevalence of CAD and/or CCAs.

METHODS

Sixty-five consecutive athletes showing electrocardiographic findings positive or equivocal for myocardial ischemia on exercise stress testing during pre-participation screening were investigated with CCTA.

RESULTS

Among the 65 athletes investigated, 36 showed Myocardial Bridge (MB), one showed an anomalous coronary origin and seven showed CAD. Among 36 athletes with MB, 4 were associated with mild coronary artery stenosis. Three athletes with CAD needed percutaneous transluminal coronary angioplasty or coronary artery bypass surgery.

CONCLUSIONS

In competitive athletes even with excellent workload capacities, in absence of cardiomyopathy, the presence of ischemic electrocardiographic abnormalities could be mainly determined by a coronary congenital or acquired pathology. In this population CCTA is a useful imaging modality of choice for the risk stratification and for the diagnostic process, to allow eligible athletes to compete and to follow-up subjects requiring medical surveillance.

Native T1 reference values for nonischemic cardiomyopathies and populations with increased cardiovascular risk: A systematic review and meta-analysis

Background

Although cardiac MR and T₁ mapping are increasingly used to diagnose diffuse fibrosis based cardiac diseases, studies reporting T₁ values in healthy and diseased myocardium, particular in nonischemic cardiomyopathies (NICM) and populations with increased cardiovascular risk, seem contradictory.

Purpose

To determine the range of native myocardial T₁ value ranges in patients with NICM and populations with increased cardiovascular risk.

Study Type

Systemic review and meta‐analysis.

Population

Patients with NICM, including hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM), and patients with myocarditis (MC), iron overload, amyloidosis, Fabry disease, and populations with hypertension (HT), diabetes mellitus (DM), and obesity.

Field Strength/Sequence

(Shortened) modified Look–Locker inversion‐recovery MR sequence at 1.5 or 3T.

Assessment

PubMed and Embase were searched following the PRISMA guidelines.

Statistical Tests

The summary of standard mean difference (SMD) between the diseased and a healthy control populations was generated using a random‐effects model in combination with meta‐regression analysis.

Results

The SMD for HCM, DCM, and MC patients were significantly increased (1.41, 1.48, and 1.96, respectively, P < 0.01) compared with healthy controls. The SMD for HT patients with and without left‐ventricle hypertrophy (LVH) together was significantly increased (0.19, P = 0.04), while for HT patients without LVH the SMD was zero (0.03, P = 0.52). The number of studies on amyloidosis, iron overload, Fabry disease, and HT patients with LVH did not meet the requirement to perform a meta‐analysis. However, most studies reported a significantly increased T₁ for amyloidosis and HT patients with LVH and a significant decreased T₁ for iron overload and Fabry disease patients.

Data Conclusions

Native T₁ mapping by using an (Sh)MOLLI sequence can potentially assess myocardial changes in HCM, DCM, MC, iron overload, amyloidosis, and Fabry disease compared to controls. In addition, it can help to diagnose left‐ventricular remodeling in HT patients.

Level of Evidence: 2

Technical Efficacy: Stage 3

J. Magn. Reson. Imaging 2018;47:891–912.

The effects of changes in utilization and technological advancements of cross-sectional imaging on radiologist workload

RATIONALE AND OBJECTIVES

To examine the effect of changes in utilization and advances in cross-sectional imaging on radiologists' workload.

MATERIALS AND METHODS

All computed tomography (CT) and magnetic resonance imaging (MRI) examinations performed at a single institution between 1999 and 2010 were identified and associated with the total number of images for each examination. Annual trends in institutional numbers of interpreted examinations and images were translated to changes in daily workload for the individual radiologist by normalizing to the number of dedicated daily CT and MRI work assignments, assuming a 255-day/8-hour work day schedule. Temporal changes in institutional and individual workload were assessed by Sen's slope analysis (Q = median slope) and Mann-Kendall test (Z = Z statistic).

RESULTS

From 1999 to 2010, a total of 1,517,149 cross-sectional imaging studies (CT = 994,471; MRI = 522,678) comprising 539,210,581 images (CT = 339,830,947; MRI = 199,379,634) were evaluated at our institution. Total annual cross-sectional studies steadily increased from 84,409 in 1999 to 147,336 in 2010, representing a twofold increase in workload (Q = 6465/year, Z = 4.2, P < .0001). Concomitantly, the number of annual departmental cross-sectional images interpreted increased from 9,294,140 in 1990 to 94,271,551 in 2010, representing a 10-fold increase (Q = 8707876/year, Z = 4.5, P < .0001). Adjusting for staffing changes, the number of images requiring interpretation per minute of every workday per staff radiologist increased from 2.9 in 1999 to 16.1 in 2010 (Q = 1.7/year, Z = 4.3, P < .0001).

CONCLUSIONS

Imaging volumes have grown at a disproportionate rate to imaging utilization increases at our institution. The average radiologist interpreting CT or MRI examinations must now interpret one image every 3-4 seconds in an 8-hour workday to meet workload demands.

Role of CMR imaging in risk stratification for sudden cardiac death

Left ventricular ejection fraction as determined by echocardiography has a limited sensitivity in predicting risk for sudden cardiac death (SCD). Subsequent efforts to improve cost-effectiveness of device implantation and identify a better risk-stratifying tool have been quite desirable. The presence of scar and myocardial tissue heterogeneity has been linked to ventricular arrhythmia, which is believed to be the major cause of SCD. Cardiac magnetic resonance is a noninvasive imaging modality that visualizes and quantifies scar, with growing evidence delineating its additive value in identifying patients at higher risk for SCD.

A silent cause of sudden cardiac death especially in sport: congenital coronary artery anomalies

AIM

To raise awareness of congenital coronary artery anomalies (CCAAs) as an important cause of sudden cardiac death (SCD) in athletes, we describe a cohort of the malignant subset. Defining the key anatomical features for the cardiologist and pathologist to be aware of and detailing a systematic approach to examining the coronary arteries at autopsy.

METHODS

Retrospective non-case-controlled analysis of 2304 cases of SCD referred by pathologists between 1994 and January 2012.

RESULTS

31 (1.3%) of the 2304 cases of SCD had CCAAs; 24 men (77%) and 7 women (23%), mean age 28 years (range 16 months-63 years). In 15 cases (48%), SCD occurred during or immediately after physical exertion. Cardiac symptoms were documented to have occurred in only seven patients (23%) prior to SCD. The anomaly had been identified by the referring pathologist in only 11 of the 31 cases (35%).

CONCLUSIONS

CCAAs are a rare and mostly benign entity, but a subset has the potential to be fatal without any forewarning. In a significant proportion of cases identified in this large cohort, the victim was under exertion at the time of death, highlighting the relevance of this anomaly to the sports and exercise medicine community.

Ethnic differences in ventricular hypertrabeculation on cardiac MRI in elite football players

PURPOSE

Left ventricular (LV) trabeculation may be more pronounced in ethnic African than in Caucasian (European) athletes, leading to possible incorrect diagnosis of left ventricular non-compaction cardiomyopathy (LVNC). This study investigates ethnic differences in LV hypertrabeculation amongst elite athletes with cardiac magnetic resonance (CMR) and electrocardiography (ECG).

METHODS

38 elite male football (soccer) players (mean age 23.0, range 19-34 years, 28/38 European, 10/38 African) underwent CMR and ECG. Hypertrabeculation was assessed using the ratio of non-compacted to compacted myocardium (NC/C ratio) on long-axis and short-axis segments. ECGs were systematically rated.

RESULTS

No significant differences were seen in ventricular volumes, wall mass or E/A ratio, whereas biventricular ejection fraction (EF) was significantly lower in African athletes (European/African athletes LVEF 55/50 %, p = 0.02; RVEF 51/48 %, p = 0.05). Average NC/C ratio was greater in African athletes but only significantly at mid-ventricular level (European/African athletes: apical 0.91/1.00, p = 0.65; mid-ventricular 0.89/1.45, p < 0.05; basal 0.40/0.46, p = 0.67). ECG readings demonstrated no significant group differences, and no correlation between ECG anomalies and hypertrabeculation.

CONCLUSIONS

A greater degree of LV hypertrabeculation is seen in healthy African athletes, combined with biventricular EF reduction at rest. Recognition of this phenomenon is necessary to avoid misdiagnosis of LVNC.

Noninvasive imaging modalities and sudden cardiac arrest in the young: can they help distinguish subjects with a potentially life-threatening abnormality from normals?

Sudden cardiac arrest (SCA) in the young is always tragic, but fortunately it is an unusual event. When it does occur, it usually happens in active individuals, often while they are participating in physical activity. Depending on the population's characteristics, the most common causes of sudden cardiac arrest in these subjects are hypertrophic cardiomyopathy, congenital coronary abnormalities, arrhythmia in the presence of a structurally normal heart (ion channelopathies or abnormal conduction pathways), aortic rupture, and arrhythmogenic right-ventricular cardiomyopathy. Two-dimensional echocardiography (2-DE) has been proposed as a screening tool that can potentially detect four of these five causes of SCA, and many groups now sponsor community-based 2-DE SCA-screening programs. "Basic" 2-DE screening may include assessment of ventricular volumes, mass, and function; left atrial size; and cardiac and thoracic vascular (including coronary) anatomy. "Advanced" echocardiographic techniques, such as tissue Doppler and strain imaging, can help in diagnosis when the history, electrocardiogram (ECG), and/or standard 2-DE screening suggest there may be an abnormality, e.g., to help differentiate those with "athlete's heart" from hypertrophic or dilated cardiomyopathy. Cardiac magnetic resonance imaging or cardiac computed tomography can be added to increase diagnostic sensitivity and specificity in select cases when an abnormality is suggested during SCA screening. Test availability, cost, and ethical issues related to who to screen, as well as the detection of those with potential disease but low risk, must be balanced when deciding what tests to perform to assess for increased SCA risk.

Phidippides cardiomyopathy: a review and case illustration

Phidippides was a Greek messenger who experienced sudden death after running more than 175 miles in two days. In today's world, marathon running and other endurance sports are becoming more popular and raising concern about sudden deaths at these events. Once etiologies such has hypertrophic cardiomyopathy, anomalous coronary arteries, and coronary atherosclerosis have been excluded, there is now an additional consideration termed Phidippides cardiomyopathy. Because endurance sports call for a sustained increase in cardiac output for several hours, the heart is put into a state of volume overload. It has been shown that approximately one-third of marathon runners experience dilation of the right atrium and ventricle, have elevations of cardiac troponin and natriuretic peptides, and in a smaller fraction later develop small patches of cardiac fibrosis that are the likely substrate for ventricular tachyarrhythmias and sudden death. Cardiac magnetic resonance imaging is emerging as the diagnostic test of choice for this condition. This review and case report summarizes the key features of this newly appreciated disorder.

Cardiovascular screening of adolescent athletes

A preparticipation cardiovascular screening is recommended for all athletes with the aim of identifying conditions that increase the risk for adverse cardiac event, including sudden death. History and physical examination are the mainstay of cardiovascular screening of young athletes. The ability to identify athletes at risk, however, based on history and physical examination alone is low, and inclusion of an electrocardiogram as a screening tool has been suggested to improve the sensitivity of screening. This article provides an overview of key aspects of cardiovascular screening currently recommended in the United States for young athletes.

Screening for proximal coronary artery anomalies with 3-dimensional MR coronary angiography

Under 35 years of age, 14% of sudden cardiac death in athletes is caused by a coronary artery anomaly (CAA). Free-breathing 3-dimensional magnetic resonance coronary angiography (3D-MRCA) has the potential to screen for CAA in athletes and non-athletes as an addition to a clinical cardiac MRI protocol. A 360 healthy men and women (207 athletes and 153 non-athletes) aged 18–60 years (mean age 31 ± 11 years, 37% women) underwent standard cardiac MRI with an additional 3D-MRCA within a maximum of 10 min scan time. The 3D-MRCA was screened for CAA. A 335 (93%) subjects had a technically satisfactory 3D-MRCA of which 4 (1%) showed a malignant variant of the right coronary artery (RCA) origin running between the aorta and the pulmonary trunk. Additional findings included three subjects with ventral rotation of the RCA with kinking and possible proximal stenosis, one person with additional stenosis and six persons with proximal myocardial bridging of the left anterior descending coronary artery. Coronary CT-angiography (CTA) was offered to persons with CAA (the CAA was confirmed in three, while one person declined CTA) and stenosis (the ventral rotation of the RCA was confirmed in two but without stenosis, while two people declined CTA). Overall 3D MRCA quality was better in athletes due to lower heart rates resulting in longer end-diastolic resting periods. This also enabled faster scan sequences. A 3D-MRCA can be used as part of the standard cardiac MRI protocol to screen young competitive athletes and non-athletes for anomalous proximal coronary arteries.

The effect of age in the cardiac MRI evaluation of the athlete's heart

PURPOSE

Increasing age is accompanied by a higher risk of sports-related death, especially from coronary disease and cardiomyopathies. It is unclear if the mature athlete's heart differs from young athletes. Our aim was to assess the effect of age on ventricular volumes and wall-mass. We also established maximum cardiac MRI (CMR) reference values in mature athletes to facilitate differentiation from cardiomyopathy.

METHODS

143 healthy persons aged 40-60 years (mean age 49±6 years [±SD], 39% women) underwent CMR: 78 athletes (exercising 9-18 h/week), and 65 age and gender matched non-athletes (≤3 h/week). From a larger study, cardiac MRI data of 195 healthy persons aged 18-39 years (mean age 28±6, 48% women) were included for statistical analysis: 81 athletes and 114 matched non-athletes.

RESULTS

With multivariate analysis, age only has limited effect on ventricular volumes (LV 1%, RV 3%) and wall-mass (0.01%). Only athletes show significant decrease in right and left ventricular volumes and LV-mass with increasing age (p<0.05). RV wall-mass remains unaffected by age. Ventricular diameters, volumes and wall-mass are significantly lower in mature athletes compared to young athletes, and significantly higher compared to mature non-athlete controls (p<0.05).

CONCLUSIONS

Only athletes show a significant decrease in ventricular volumes and LV wall-mass with increasing age, which probably reflects decreasing training intensity rather than the effect of age. Mature athletes form a distinct group requiring separate reference values as they have significantly lower ventricular volumes and wall-mass as compared to young athletes, however, still significantly higher values than mature non-athletes.