Quantification of sonographic echogenicity with grey-level histogram width: a clinical tissue characterization

Area of Science:

• Medical Imaging
• Ultrasound Technology
• Quantitative Sonography

Background:

• Grey-level histogram width (GLHW) varies with tissue echogenicity in ultrasound imaging.
• Standardization of GLHW measurements across different sonographic devices is crucial for clinical applications.

Purpose of the Study:

• To evaluate the reproducibility of Grey-level histogram width (GLHW) measurements across various commercial ultrasound devices.
• To establish normal ranges for GLHW in pregnancy and assess its utility in differentiating normal from abnormally echogenic placentas.

Main Methods:

• Testing GLHW values using an RMI-412 phantom across different sonographs (Aloka UIP-100, Toshiba SSA-270A, SSD-680) at minimal contrast settings.
• Analyzing the influence of device gain, STC, and image depth on GLHW.
• Establishing normal GLHW ranges in 222 normal pregnancies from 20 to 41 weeks gestation.
• Comparing GLHW values of normal placentas and Grannum Grade III placentas.

Main Results:

• GLHW values were reproducible across tested sonographic devices, with minor adjustments for inter-device differences.
• Device gain, STC, and image depth did not significantly affect GLHW within clinical ranges.
• Device contrast setting was found to influence GLHW.
• Measured GLHW values for normal pregnancies fell within established ranges, while Grade III placentas showed values above the normal upper limit.
• Manual and automated GLHW measurements yielded identical results.

Conclusions:

• Grey-level histogram width (GLHW) is a reproducible quantitative ultrasound parameter.
• GLHW measurements are consistent across different commercial ultrasound devices and unaffected by common clinical adjustments.
• GLHW is a valuable tool for assessing placental echogenicity and can aid in the diagnosis of abnormally echogenic placentas.