Cardiovascular MR Imaging in Cardio-oncology

Measurement of Ejection Fraction by Cardiac Magnetic Resonance Imaging and Echocardiography to Monitor Doxorubicin-Induced Cardiotoxicity

Doxorubicin is a standard treatment option for breast cancer, lymphoma, and leukemia, but its benefits are limited by its potential for cardiotoxicity. The primary objective of this study was to compare cardiac magnetic resonance imaging (CMRI) versus echocardiography (ECHO) to detect a reduction in left ventricular ejection function, suggestive of doxorubicin cardiotoxicity. We studied eligible patients who were 18 years or older, who had breast cancer or lymphoma, and who were offered treatment with doxorubicin with curative intent dosing of 240 to 300 mg/m ² body surface area between March 1, 2009 and October 31, 2013. Patients underwent baseline CMRI and ECHO. Both imaging studies were repeated after four cycles of treatment. Ejection fraction (EF) calculated by both methods was compared and analyzed with the inferential statistical Student's t test. Twenty-eight eligible patients were enrolled. Two patients stopped participating in the study before undergoing baseline CMRI; 26 patients underwent baseline ECHO and CMRI. Eight of those 26 patients declined posttreatment studies, so the final study population was 18 patients. There was a significant difference in EF pre- and posttreatment in the CMRI group ( p  = 0.009) versus the ECHO group that showed no significant differences in EF ( p  = NS). It appears that CMRI is superior to ECHO for detecting doxorubicin-induced reductions in cardiac systolic function. However, ECHO is less expensive and more convenient for patients because of its noninvasive character and bedside practicality. A larger study is needed to confirm these findings.

MRI in cardio-oncology: A review of cardiac complications in oncologic care

From detailed characterization of cardiac abnormalities to the assessment of cancer treatment-related cardiac dysfunction, cardiac MRI is playing a growing role in the evaluation of cardiac pathology in oncology patients. Current guidelines are now incorporating the use of MRI for the comprehensive multidisciplinary approach to cancer management, and innovative applications of MRI in research are expanding its potential to provide a powerful noninvasive tool in the arsenal against cancer. This review focuses on the application of cardiac MRI to diagnose and manage cardiovascular complications related to cancer and its treatment. Following an introduction to current cardiac MRI methods and principles, this review is divided into two sections: functional cardiovascular analysis and anatomical or tissue characterization related to cancer and cancer therapeutics. Level of Evidence: 5 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2019;50:1349-1366.

Cardiac Magnetic Resonance Imaging in Oncology

BACKGROUND

Cardiac magnetic resonance imaging (MRI) is emerging as an important diagnostic modality in the management of cardiovascular-related dysfunction in oncological diseases. Advances in imaging techniques have enhanced the detection and evaluation of cardiac masses; meanwhile, innovative applications have created a growing role for cardiac MRI for the management of cardiotoxicity caused by cancer therapies.

METHODS

An overview is provided of the clinical indications and technical considerations of cardiac MRI. Its role in the evaluation of cardiac masses and cardiac function is reviewed, and novel sequences are discussed that are giving rise to future directions in cardio-oncology research. A review of the literature was also performed, focusing on cardiac MRI findings associated with cardiac dysfunction related to cancer treatment.

RESULTS

Cardiac MRI can be used to differentiate benign and malignant primary cardiac tumors, metastatic disease, and pseudotumors with high spatial and temporal resolution. Cardiac MRI can also be used to detect the early and long-term effects of cardiotoxicity related to cancer therapy. This is accomplished through a multiparametric approach that uses conventional bright blood, dark blood, and postcontrast sequences while also considering the applicability of newer T1 and T2 mapping sequences and other emerging techniques.

CONCLUSIONS

Cardio-oncology programs have an expanding presence in the multidisciplinary approach of cancer care. Consequently, knowledge of cardiac MRI and its potential applications is critical to the success of contemporary cancer diagnostics and cancer management.

Electrocardiographic abnormalities and mortality in aging survivors of childhood cancer: A report from the St Jude Lifetime Cohort Study

BACKGROUND

Electrocardiography (ECG), predictive of adverse outcomes in the general population, has not been studied in cancer survivors. We evaluated the prevalence of ECG abnormalities and associations with mortality among childhood cancer survivors.

METHODS

Major and minor abnormalities were coded per the Minnesota Classification system for participants in the St Jude Lifetime Cohort Study (n = 2,715) and community controls (n = 268). Odds ratios (ORs) and 95% CIs were calculated using multivariable logistic regression; and hazard ratios, using Cox proportional hazards regression.

RESULTS

Survivors were a median age of 31.3 (range 18.4-63.8) years at evaluation and 7.4 (range 0-24.8) years at diagnosis. Prior therapies included cardiac-directed radiation (29.5%), anthracycline (57.9%), and alkylating (60%) chemotherapies. The prevalence of minor ECG abnormalities was similar among survivors and controls (65.2% vs 67.5%, P = .6). Major ECG abnormalities were identified in 10.7% of survivors and 4.9% of controls (P < .001). Among survivors, the most common major abnormalities were isolated ST/T wave abnormalities (7.2%), evidence of myocardial infarction (3.7%), and left ventricular hypertrophy with strain pattern (2.8%). Anthracyclines ≥300 mg/m² (OR 1.7 95% CI 1.1-2.5) and cardiac radiation (OR 2.1 95% CI 1.5-2.9 [1-1,999 cGy], 2.6 95% CI 1.6-3.9 [2,000-2,999 cGy], 10.5 95% CI 6.5-16.9 [≥3,000 cGy]) were associated with major abnormalities. Thirteen participants had a cardiac-related death. Major abnormalities were predictive of all-cause mortality (hazard ratio 4.0 95% CI 2.1-7.8).

CONCLUSIONS

Major ECG abnormalities are common among childhood cancer survivors, associated with increasing doses of anthracyclines and cardiac radiation, and predictive of both cardiac and all-cause mortality.

Role of Imaging in Cardio-Oncology

OPINION STATEMENT

Recent advances in cancer treatment and research have greatly improved survival rates for patients with cancer. However, many of these cancer survivors are developing cardiac disease-most commonly heart failure as a result of this treatment. Certain chemotherapeutic agents, including anthracyclines and trastuzumab, have been linked to cardiotoxicity-induced cardiomyopathy in cancer patients. It has been reported as early as during infusion and as late as several years following treatment. Radiation therapy, particularly to the left breast, has also been linked to cardiac disease. The responsibility of cardiac monitoring has traditionally fallen on oncologists using assessment of LVEF through multigated acquisition (MUGA) scans or echocardiograms. The "formal" definition of cardiotoxicity, as a 5 to 10% decrease in LVEF from its baseline, even though not validated, is currently used by clinicians to alter treatment, but it has been recently challenged, as a possible irreversible late stage of a myocardial insult. Furthermore, it falls into the interobserver variability range of echocardiography. The growing field of medicine called cardio-oncology is based on emerging research that has shown that more advanced imaging modalities can help detect cardiotoxicity early, allowing the patient to receive treatment and avoid developing heart failure from cancer treatment. While traditional imaging still has its place in cardiac monitoring, cardiac magnetic resonance imaging is the most accurate and detailed imaging modality available to assess cardiotoxicity. Our own pilot cardiac MRI study suggests that a normal left ventricular remodeling to chemotherapy, when patients have not developed heart failure symptoms, could occur over time. Perhaps, knowing a baseline normal response could help us to define a more accurate definition of cardiotoxicity by CMR. Here, we discuss various imaging modalities and emerging techniques that can assist in detecting early signs of cardiotoxicity and thus reduce the incidence of cardiac disease in cancer survivors.

Left Ventricular Function Evaluation on a 3T MR Scanner with Parallel RF Transmission Technique: Prospective Comparison of Cine Sequences Acquired before and after Gadolinium Injection

Objectives

To compare cine MR b-TFE sequences acquired before and after gadolinium injection, on a 3T scanner with a parallel RF transmission technique in order to potentially improve scanning time efficiency when evaluating LV function.

Methods

25 consecutive patients scheduled for a cardiac MRI were prospectively included and had their b-TFE cine sequences acquired before and right after gadobutrol injection. Images were assessed qualitatively (overall image quality, LV edge sharpness, artifacts and LV wall motion) and quantitatively with measurement of LVEF, LV mass, and telediastolic volume and contrast-to-noise ratio (CNR) between the myocardium and the cardiac chamber. Statistical analysis was conducted using a Bayesian paradigm.

Results

No difference was found before or after injection for the LVEF, LV mass and telediastolic volume evaluations. Overall image quality and CNR were significantly lower after injection (estimated coefficient cine after > cine before gadolinium: -1.75 CI = [-3.78;-0.0305], prob(coef>0) = 0% and -0.23 CI = [-0.49;0.04], prob(coef>0) = 4%) respectively), but this decrease did not affect the visual assessment of LV wall motion (cine after > cine before gadolinium: -1.46 CI = [-4.72;1.13], prob(coef>0) = 15%).

Conclusions

In 3T cardiac MRI acquired with parallel RF transmission technique, qualitative and quantitative assessment of LV function can reliably be performed with cine sequences acquired after gadolinium injection, despite a significant decrease in the CNR and the overall image quality.

Pathophysiology and preventive strategies of anthracycline-induced cardiotoxicity

Cardiotoxicity is a well-known complication following treatment with anthracyclines. However, they are still widely used in chemotherapy for breast cancer, lymphoma, leukemia, and sarcoma, among others. Patient clinical characteristics, such as age, sex, comorbidities, anthracycline dose and infusion schedule, and the combined anti-cancer agents used, are diverse among cancer types. It is difficult to recommend guidelines for the prevention or management of anthracycline-induced cardiotoxicity applicable to all cancer types. Therefore, anthracycline-induced cardiotoxicity remains a major limitation in the proper management of cancer patients treated with an anthracycline-combined regimen. Efforts have been extensive to determine the mechanism and treatment of anthracycline-induced cardiotoxicity. Because cardiotoxicity causes irreversible damage to the myocardium, prevention is a more effective approach than treatment of cardiotoxicity after symptomatic or asymptomatic cardiac dysfunction develops. This article will review the pathophysiological mechanisms of anthracycline-induced cardiotoxicity and strategies for protecting the myocardium from anthracycline.

Breast cancer therapy-associated cardiovascular disease

Breast cancer treatments have evolved over the past decades, although several widely used treatments have adverse cardiac effects. Radiotherapy generally improves the survival of women with breast cancer, although its deleterious cardiovascular effects pose competing risks of morbidity and/or mortality. In the past, radiation-associated cardiovascular disease was a phenomenon considered to take more than a decade to manifest, but newer research suggests that this latency is much shorter. Knowledge of coronary anatomy relative to the distribution of the delivered radiation dose has improved over time, and as a result, techniques have enabled this risk to be decreased. Studies continue to be performed to better understand, prevent and mitigate against radiation-associated cardiovascular disease. Treatments such as anthracyclines, which are a mainstay of chemotherapy for breast cancer, and newer targeted agents such as trastuzumab both have established risks of cardiotoxicity, which can limit their effectiveness and result in increased morbidity and/or mortality. Interest in whether β-blockers, statins and/or angiotensin-converting enzyme (ACE)-inhibitors might have therapeutic and/or preventative effects in these patients is currently increasing. This Review summarizes the incidence, risks and effects of treatment-induced cardiovascular disease in patients with breast cancer and describes strategies that might be used to minimize this risk.