Ultrasound myocardial tissue characterization by integrated backscatter in children treated with anthracyclines

The objective of our study was to evaluate integrated backscatter (IBS) measurement, an ultrasound method of myocardial tissue characterization, in children receiving cardiotoxic anthracyclines for malignancy. Myocardial injury is known to diminish the normal cyclic variation of IBS (CVIBS) during the cardiac cycle. We used a cross-sectional, case-controlled study of children receiving anthracyclines and serial, prospective observation in a subgroup of children. The study took place in a university-affiliated, tertiary referral center for pediatric cardiology and oncology. Children undergoing routine echocardiograms before, during, and after anthracycline treatment participated in this study. Children evaluated in the cardiology clinic for innocent murmurs participated as controls. There was no intervention. CVIBS was measured using specialized echocardiographic software which quantitates the intensity of backscattered echoes returning from myocardial cells within a user-defined region of interest. Standard echocardiographic measures of left ventricular function were also made. The results indicated that abnormal CVIBS was prevalent during anthracycline treatment (17%) and at late follow-up (20%). In serial studies, CVIBS decreased in all children after anthracycline treatment. Anthracycline dose and time since last dose did not predict which children would have abnormalities of left ventricular function or of CVIBS. This report provides preliminary evidence that CVIBS may be a useful supplement to the noninvasive, echocardiographic assessment of the heart during anthracycline treatment in children.