Generation of 3D ultrasound biomicroscopic images: technique validation and in vivo volumetric imaging of rat lateral gastrocnemius

Abstract

Introduction: Ultrasound biomicroscopy (UBM) is a technique for generating high-resolution images, with frequencies from 20 MHz to 100 MHz. For example, it has been used in animal research related to models of injury and diseases that mimic human conditions. With a three-dimensional ultrasound (3D) image system, an organ can be viewed at various angles and the volume estimated, contributing to an accurate diagnosis. This work refers to the generation of 3D-UBM images, employing a 35 MHz ultrasound system, from multiple two-dimensional (2D) images. Phantoms were used to validate the technique and to determine its reliability of volume measurements. Additionally, the technique was used to obtain 3D images of the rat gastrocnemius muscle. Methods: Four different phantoms were used and ten acquisition sequences of 2D-images acquired for each one. Thereafter, 5 volume segmentations were performed for each acquisition sequence, resulting in 50 measured volumes for each phantom. The physical volumes of all phantoms were used to validate the technique based on the coefficient of variation (CV) and the intraclass correlation coefficient (ICC). Images of the gastrocnemius muscle were acquired and the partial volume quantified. Results: The CV and ICC confirmed the reliability of volume measurements obtained by segmentation. Moreover, cross-sectional 2D images of rat hindlimb were obtained, allowing to identify the gastrocnemius muscle and to partially quantify the muscle volume from 3D images. Conclusion: The results indicated that the technique is valid to generate 3D images and quantify the volume of a muscle compatible with the dimensions of a small animal.

Three-dimensional Visualization of Ultrasound Backscatter Statistics by Window-modulated Compounding Nakagami Imaging

“…46 In vivo volumetric imaging of the rat lateral gastrocnemius muscle was made through the generation of 3D ultrasound biomicroscopic images. 47 Quantitative volumetric imaging of normal, neoplastic, and hyperplastic mouse prostates was also implemented using 3D ultrasound. 48 It should be noted that 3D ultrasound imaging has been widely applied to morphology or volumetric measurements, but the literature details few applications to tissue characterization.…”