Effectiveness of strain-encoding cardiac magnetic resonance imaging (SENC-CMR) in detecting subclinical cardiotoxicity in in childhood cancer survivors treated with anthracyclines (RF_TH_201)

Preliminary studies in adults indicate that Strain-Encoded Imaging (SENC) can detect early signs of chemotherapy-induced cardiotoxicity, even before changes in left ventricular ejection fraction become apparent, potentially guiding earlier interventions.^1,2 Advanced tagged CMR sequences, such as fast-SENC, enable quantification of global longitudinal (GLS) and circumferential strain (GCS) magnitude, MyoHealth (% normal myocardium ≤ -17) add to our understanding of myocardial mechanical adaptation to cardiac injury. This retrospective study aims to assess the effectiveness of SENC-CMR in detecting subclinical cardiotoxicity in pediatric cancer patients treated with Anthracycline (AC) therapy, comparing its performance to conventional echocardiography and standard cardiac magnetic resonance imaging (CMR) parameters.

Methods: This study involved 70 consecutive childhood cancer survivors, aged 2 to 29 years, with a median age of 14 years (IQR: 8.25-19), including 44.8% females. All participants had received anthracycline (AC) therapy, with a median cumulative dose of 245.8 mg/m² (IQR: 126.6-374.1). Each patient underwent comprehensive cardiac assessment using echocardiography, standard cardiac magnetic resonance imaging (CMR), and strain-encoded CMR (SENC-CMR). Patients were categorized according to the American Heart Association (AHA) heart failure stages (A, B, C) and analyzed with a specific focus on Stage B (n=38).

Results: In Stage B patients, SENC-CMR using MyoStrain GLS (-15.6, p=0.004), GCS (-18.95, p< 0.001) and MyoHealth 57.0% (p< 0.001), demonstrated superior sensitivity in detecting subclinical myocardial dysfunction compared to conventional CMR parameters such as LVEF (54.0%, p< 0.001), left ventricular mass index (55.0 g/m², p=0.10), and echocardiography-derived GLS (-21.5, p=0.024) and GCS (-27.0, p=0.006). Feature tracking derived strain (Q strain) had decreased sensitivity in identifying Stage B patients when compared to SENC-CMR (Table 1).  CMR identified a greater proportion of Stage B patients with LVEF below 55% (21/38) compared to echocardiography (5/38). Conventional CMR parameters, including LV volumes and mass/volume ratio (0.66, p=0.003), were less effective in detecting subtle, early myocardial changes compared to SENC-CMR (Table 1). MyoHealth decreased with advancing heart failure stage (Figure 1) and showed improved function in pediatric cancer patients and survivors, with greater sensitivity to ejection fraction (EF) and stroke volume index (SVI) (Figure 2).

Conclusion: SENC-CMR, utilizing MyoHealth and MyoStrain-derived GLS and GCS, is more sensitive than both standard CMR and echocardiographic parameters, including LVEF, ESVi, EDVi, SVi, and echo and Q-strain-derived GLS and GCS, in identifying early subclinical cardiotoxicity in Stage B pediatric cancer patients treated with anthracyclines. By detecting early myocardial impairment before significant functional decline occurs, SENC-CMR enables timely intervention, potentially preventing progression to symptomatic heart failure. These findings support the integration of SENC-CMR into routine cardiac monitoring for oncology patients at risk of cardiotoxicity.

Figure 1. MyoHealth % and LVEF across Heart Failure Stages (A, B, C): SENC-CMR, MyoHealth utilizing MyoStrain derived GLS and GCS, is more sensitive than standard CMR derived LVEF in identifying early subclinical cardiotoxicity in Stage B cancer patients treated with anthracyclines.
Figure 1.docx.pdf
Figure 2. MyoStrain Monitors Improvement in Function for Pediatric Cancer Patients / Survivors with higher sensitivity to EF and SVI.
Figure 2.docx.pdf