Opacification patterns of cardiac masses using low-mechanical index contrast echocardiography: comparison with histopathological findings.

Abstract

Two-dimensional echocardiography is the main noninvasive imaging tool to identify cardiac masses but is unable to provide detailed tissue characterization. The aim of the study was to assess the ability of low mechanical index (MI) contrast echocardiography to detect presence and amount of tissue vascularization as validated by histopathology study of cardiac masses. Twelve consecutive patients (5 females and 7 males, age range 51-82 years) underwent conventional and contrast two-dimensional echocardiography with low MI. By contrast echocardiography, mass enhancement was classified as absent (suggesting thrombus), partial, or complete (suggesting vascularized mass, both with early or late >20 cycles of opacification) as compared to the adjacent myocardium. The precise nature of the cardiac masses was provided by histopathology examination and/or by resolution after anticoagulation therapy during follow-up. Presence, type, and degree of mass vascularization were assessed by histology, immunohistochemistry, and morphometric analysis. Among the 12 cases, mass enhancement was absent, late and peripheral, late and partial, and early and complete in three cases each. Cardiac masses consisted of thrombus (three), secondary malignant cardiac tumor (three), myxoma (three), papillary fibroelastoma (two), and cavernous hemangioma (one). At histology, cardiac hemangioma had the highest degree of vascularization, at difference from thrombi which were not vascularized, and data were in keeping with contrast echocardiography findings. Low MI contrast echocardiography is an easy, noninvasive cardiac imaging tool to assess cardiac mass vascularization. The degree of contrast enhancement and time to opacification are highly variable among cardiac masses and correspond to different extent of vascularization.