June 14, 2013Open Access

Dynamic variations in the ultrasound greyscale median of carotid artery plaques

Q: What is the clinical evidence from this study?

Study design: Observational. Population: Carotid artery plaques (n=19). Intervention: Frame-by-frame ultrasound greyscale median (GSM) measurement vs. Still ultrasound images. Primary outcome: Inter-frame coefficient of variation (CV) for greyscale median (GSM).

BKBaris KanberQueen Mary University of London THTimothy HartshorneUniversity of Leicester MHMark A. HorsfieldUniversity of Essex

Key Result

Frame-by-frame ultrasound analysis of carotid artery plaques revealed a mean inter-frame coefficient of variation of 5.2% for greyscale median, indicating significant dynamic variations.

Study Design

Type

Observational (n=19)

Multicenter

PICO

Population

19 consecutive patients (mean age 76, 42.1% female) with 27 carotid artery plaques (stenosis range 10%-80%) undergoing ultrasound imaging.

Exposure / Comparator

Frame-by-frame ultrasound greyscale median (GSM) measurement vs Still ultrasound images

Primary Outcome

Inter-frame coefficient of variation (CV) for greyscale median (GSM)

Limitations

Use of two-dimensional ultrasound providing only a cross-section of the whole plaque volume.
Susceptibility to variations due to out-of-plane plaque, probe, and patient motion.
Exclusion of anechoic regions and regions of acoustic shadowing from analysis.
Absence of attempts to fix the scan plane location and orientation beyond normal clinical measures.

Abstract

BACKGROUND: Several studies have found that the ultrasound greyscale median (GSM) of carotid artery plaques may be useful for predicting the risk of cerebrovascular events. However, measurements of GSM are typically performed on still ultrasound images ignoring any variations that may be observed on a frame-by-frame basis. The aim of this study was to establish the existence and investigate the nature and extent of these variations. METHODS: Employing a novel method that enabled plaque boundaries to be tracked semi-automatically, variations in the plaque GSM and observed cross-sectional area were measured for 27 carotid artery plaques (19 consecutive patients, stenosis range 10%-80%) over image sequences of up to 10 seconds in length acquired with a mean frame rate of 32 frames per second. RESULTS: Our results showed a mean inter-frame coefficient of variation (CV) of 5.2% (s.d. 2.5%) for GSM and 4.2% (s.d. 2.9%) for the plaque area. Thirteen of the 27 plaques (48%) exhibited CV in GSM greater than 5% whereas only six plaques (22%) had CV in plaque area of greater than 5%. There was no significant correlation between the CV of GSM and plaque area. CONCLUSIONS: Inter-frame variations in the plaque GSM such as those found in this study have implications on the reproducibility of GSM measurements and their clinical utility. Studies assessing the GSM of carotid artery plaques should consider these variations.

Ask AI

Helpful

Bookmark

View Full Paper

Ask AI

Helpful

Bookmark

View Full Paper

Cite This Study

Kanber et al. (Fri,) conducted a observational in Carotid artery plaques (n=19). Frame-by-frame ultrasound greyscale median (GSM) measurement vs. Still ultrasound images was evaluated on Inter-frame coefficient of variation (CV) for greyscale median (GSM). Frame-by-frame ultrasound analysis of carotid artery plaques revealed a mean inter-frame coefficient of variation of 5.2% for greyscale median, indicating significant dynamic variations.

synapsesocial.com/papers/6a7714f4576efb0ddaf710f2 https://doi.org/https://doi.org/10.1186/1476-7120-11-21