Diagnostic ultrasound is a form of energy that has the potential for effects in tissues (bioeffects). The 2 most likely mechanisms are heating and cavitation. The thermal index (TI) expresses the potential for rise in temperature. The MI indicates the potential for the ultrasound to induce inertial cavitation. Scarce data exist regarding instrument’s acoustic output for routine ultrasound examinations. Data collected during routine ultrasound examinations (first trimester for viability, nuchal translucency, anatomy surveys including 3-dimensional/4-dimensional studies and growth studies) show that “gray-scale” B-mode ultrasound is associated with a negligible rise in TI. However, Doppler studies show significantly higher levels of TI, which can reach 1.5 and above.
*Department of Obstetrics and Gynecology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
†Department of Obstetrics and Gynecology;
‡Rush Fetal and Neonatal Medicine Center, Rush University Medical Center, Chicago, Illinois
The authors declare that they have nothing to disclose.
Correspondence: Eyal Sheiner, MD, PhD, Department of Obstetrics and Gynecology, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel. E-mail: firstname.lastname@example.org