Benefits associated with harmonic tissue imaging in the obstetric patient

Objective: We sought to determine the impact of harmonic tissue imaging on image resolution and visualization of fetal structures during obstetric ultrasonography. Study Design: Patients with singleton second- or third-trimester fetuses were recruited. Prospective comparisons of conventional fundamental imaging and harmonic tissue imaging were made. Visualization rates and frequencies of improvement in resolution were calculated. Discriminate function analysis evaluated determinants of improved visualization. Results: Harmonic tissue imaging improved resolution of at least one fetal structure in 51.4% of patients studied. Differences were most marked for 4-chamber views of the heart with improvement in resolution in 30.5% of patients and change in ability to visualize in 9.5%. Maternal weight and gestational age had a significant influence on whether improvements were noted with harmonic tissue imaging, accounting for 27% of the variance. Conclusions: Harmonic tissue imaging offers significant improvements over fundamental imaging in image resolution and structure visualization in obese patients during the second trimester of pregnancy. (Am J Obstet Gynecol 2000;182:1620-2.)