Point of Care Transcranial Color-Coded Duplex Ultrasound of the Middle Cerebral Artery

Summary

Transcranial ultrasound is an essential tool for monitoring patients with various neurological conditions. Although it is commonly used in a protocolized fashion in consultative studies, the brain has been overlooked in many protocols utilizing point-of-care ultrasound (PoCUS). This study proposes a PoCUS image acquisition protocol.

Abstract

In the assessment and management of many clinical problems, point-of-care (PoC) ultrasound is an emerging bedside tool. Transcranial color-coded duplex (TCCD) ultrasound can be valuable in multiple situations, including for patients who are unconscious or have an equivocal neurologic examination, as it helps rule in specific intracranial pathologies. Despite the known diagnostic value of transcranial ultrasound, its use in critical care medicine remains variable. This variability is partly due to inconsistent training across hospitals, stemming from a lack of standardized education and training. Additionally, the brain has often been overlooked in many critical care protocols, such as RUSH (Rapid Ultrasound for Shock and Hypotension) and FAST (Focused Assessment with Sonography in Trauma) exams. To address these gaps, this article proposes a protocol for PoC TCCD image acquisition in adults, detailing indications, limitations, transducer selection, placement, sequence acquisition, and image optimization. Furthermore, the use of PoC TCCD is discussed as a means of screening for three conditions: vasospasm, raised intracranial pressure, and progression of cerebral circulatory arrest.

Introduction

First described by Aaslid et al. in 1982, transcranial Doppler (TCD) ultrasonography offered a method to evaluate intracranial blood flow and velocity¹. Later, transcranial color-coded duplex ultrasound (TCCD) was developed to allow color-coded visualization of intracerebral vasculature. This permits TCCD to partly overcome a limitation of TCD: angle dependence. Specifically, as a result of Doppler shift, measurements of blood flow velocity are most accurate if the angle of the ultrasound beam and the axis of the vessel are between 0-30 degrees². While flow velocity measurements in TCD assume an angle close to zero, TCCD....

Protocol

This procedure adheres to the ethical standards of the institutional committee on human experimentation and the Helsinki Declaration. Ultrasound is considered a minimal-risk procedure; therefore, written consent from the patient is generally not required. Patients with concerns about neurological changes in an appropriate clinical setting were included in the study. Those with open head wounds, surgical incisions, or surgical dressings at the insonation site were excluded. The consumables and equipment used in this study.......

Discussion

PoC ultrasound is increasingly playing a vital role in the diagnosis and management of patients with acute organ dysfunction, as seen with RUSH and FAST exams. However, when evaluating cerebral function, to date there is little published guidance for clinicians seeking to perform PoC TCCD.

To develop this PoC protocol, we chose to adapt TCCD rather than TCD imaging. In contrast to traditional TCD, TCCD combines B-mode and color Doppler, allowing for angle correction that results in more acc.......

Materials

Name	Company	Catalog Number	Comments
Low Frequency Ultrasound Probe (C35xp)	SonoSite (FujiFilm)	P19617
SonoSite X-porte Ultrasound	SonoSite (FujiFilm)	P19220
Ultrasound Gel	AquaSonic	PLI 01-08