Ultrasound tissue characterization with the gray level histogram width of the B-mode

AbstractObjectives. We investigated fetal lung immaturity, fetal brain periventricular echodensity (PVE) and other problems related to changes in fetal tissue by non-invasive ultrasound tissue characterization, using a commonly available real-time B-mode ultrasound machine.Methods. Histograms of a region of interest (ROI) were displayed on a B-mode screen. The base length of a histogram divided by the full gray-scale length gave the gray level histogram width (GLHW); this value is insensitive to changes in B-mode model, device gain or image depth. Any variation in the magnitude of GLHW in high-contrast images was easily corrected. Fetal lung immaturity was suspected when the fetal lung GLHW was less than that of normal fetal lung and fetal liver after 30 weeks of pregnancy. The GLHW values of fetal brain PVE were also compared to those of normal fetal brain.Results. GLHW values were compared between the “mature fetal lung” and the “immature fetal lung” groups, as determined by the stable microbubble test:...