Power and Color Doppler Ultrasound Settings for Inflammatory Flow: Impact on Scoring of Disease Activity in Patients With Rheumatoid Arthritis

Authors: Søren Torp-Pedersen, Robin Christensen, Marcin Szkudlarek, Karen Ellegaard, Maria Antonietta D’Agostino, Annamaria Iagnocco, Esperanza Naredo, Peter Balint, Richard J. Wakefield, Arendse Torp-Pedersen, and Lene Terslev

Published in: ARTHRITIS & RHEUMATOLOGY, Vol. 67, No. 2, February 2015, pp 386–395
DOI 10.1002/art.38940

Objective. To determine how settings for power and color Doppler ultrasound sensitivity vary on different high- and intermediate-range ultrasound machines and to evaluate the impact of these changes on Doppler scoring of inflamed joints.

Methods. Six different types of ultrasound machines were used. On each machine, the factory setting for superficial musculoskeletal scanning was used unchanged for both color and power Doppler modalities. The settings were then adjusted for increased Doppler sensitivity, and these settings were designated study settings. Eleven patients with rheumatoid arthritis (RA) with wrist involvement were scanned on the 6 machines, each with 4 settings, generating 264 Doppler images for scoring and color quantification. Doppler sensitivity was measured with a quantitative assessment of Doppler activity: color fraction. Higher color fraction indicated higher sensitivity.

Results. Power Doppler was more sensitive on half of the machines, whereas color Doppler was more sensitive on the other half, using both factory settings and study settings. There was an average increase in Doppler sensitivity, despite modality, of 78% when study settings were applied. Over the 6 machines, 2 Doppler modalities, and 2 settings, the grades for each of 7 of the patients varied between 0 and 3, while the grades for each of the other 4 patients varied between 0 and 2.

Conclusion. The effect of using different machines, Doppler modalities, and settings has a considerable influence on the quantification of inflammation.

Read the Complete Article:Power and Color Doppler settings for Inflammatory Flow

Shear-Wave Elastography: Basic Physics and Musculoskeletal Applications

Authors: Mihra S. Taljanovic, MD, PhD, Lana H. Gimber, MD, MPH, Giles W. Becker, MD, L. Daniel Latt, MD, PhD, Andrea S. Klauser, MD, David M. Melville, MD, Liang Gao, PhD, Russell S. Witte, PhD

In the past 2 decades, sonoelastography has been progressively used as a tool to help evaluate soft-tissue elasticity and add to information obtained with conventional gray-scale and Doppler ultrasonographic techniques. Recently introduced on clinical scanners, shearwave elastography (SWE) is considered to be more objective, quantitative,
and reproducible than compression sonoelastography with increasing applications to the musculoskeletal system. SWE uses an acoustic radiation force pulse sequence to generate shear waves, which propagate perpendicular to the ultrasound beam, causing transient displacements. The distribution of shear-wave velocities at each pixel is directly related to the shear modulus, an absolute measure of the tissue’s elastic properties. Shear-wave images are automatically coregistered with standard B-mode images to provide quantitative color elastograms with anatomic specificity. Shear waves propagate faster through stiffer contracted tissue, as well as along the long axis of tendon and muscle. SWE has a promising role in determining the severity of disease and treatment followup of various musculoskeletal tissues including tendons, muscles, nerves, and ligaments. This article describes the basic ultrasound physics of SWE and its applications in the evaluation of various traumatic and pathologic conditions of the musculoskeletal system.

RadioGraphics 2017; 37:855–870
Published online 10.1148/rg.2017160116

READ THE ARTICLE:  Shear Wave Elastography Physics Applications