Application of ultrasound for muscle assessment in sarcopenia: towards standardized measurements

TLDR: This review provides an evidence base for an ultrasound protocol in the assessment of skeletal muscle with the use of US and creates conditions to further test the applicability of US for use on a large scale as a routine assessment and follow-up tool for appendicular muscle.

About: This article is published in European Geriatric Medicine.The article was published on 2018-12-01 and is currently open access. It has received 112 citations till now.

Figures

Table 4 Consensus proposition, shortcomings in knowledge and protocol listings for system and system settings Consensus proposition:  All types of ultrasound machine can be used, as long as B-mode is present  Extended field of view is not necessary but recommended

Table 2 Measuring points and components of quadriceps muscles used in assessment

Table 3 Consensus proposition, shortcomings in knowledge and protocol listings for patient positioning pre-investigation Consensus proposition:  No exercise 30 min before investigation  Preferably minimum 30 min (maximum 60 min) in the same position before  Investigation, for measurements in recumbent position

Fig. 1 Overview of the study selection process using the PRISMA 2009 flow chart [166]. NCDL no clear description of location of measuring point, NCDM no clear description of muscle measured, AOS article outside of scope of manuscript, ROA referencing to other articles for measurement technique, FTNA full-text not available

Table 6 Proposed anatomical landmarks for each muscle discussed

Table 5 Consensus proposition, shortcomings in knowledge and protocol listings for components

Frequently asked questions

Q1. What are the contributions in "Application of ultrasound for muscle assessment in sarcopenia: towards standardized measurements" ?

This review aims to provide an evidence-based standardization of assessing appendicular muscle with the use of US. Through this process, five items of muscle assessment were identified in the evaluated articles: thickness, crosssectional area, echogenicity, fascicle length and pennation angle. The results of this review provide thus an evidence base for an ultrasound protocol in the assessment of skeletal muscle. This standardization of measurements is the first step in creating conditions to further test the applicability of US for use on a large scale as a routine assessment and follow-up tool for appendicular muscle. 

Q2. What have the authors stated for future works in "Application of ultrasound for muscle assessment in sarcopenia: towards standardized measurements" ?

Future directions can certainly involve changing some of the recommendations, if there is new evidence to support these changes. Hopefully, this way future studies will have an extra support to build upon. 

Q3. What can be set to have the possible view of the muscle?

Depth focus, general gain, time-gain compensation, dynamic range, etc. can be set in order to have the best possible view of the muscle that is to be assessed. 

Q4. What was assessed for muscle thickness and anatomical cross-sectional area?

At a distance of 50% between the anterior superior iliac spine and the distal border of the patella, rectus femoris was assessed for muscle thickness and anatomical cross-sectional area [93]. 

Q5. What is the way to measure the thickness of a muscle?

For measuring the maximal thickness of a muscle, it is advised not only to take the midpoint of the muscle in between the tendons, but at this point of the longitudinal axis, to use the point at 50% between the medial and lateral border of the muscle bulk. 

Q6. What is the important factor in determining strength?

In non-athletic populations, inter-limb differences in strength are possibly more related to neural factors than pure muscle-related factors [86]. 

Q7. What are the main reasons why CT and MRI are not practical?

In clinical practice, however, CT and MRI are not practical, due to the limited availability, lack of portability, high cost and radiation exposure (CT). 

Q8. What are the components that can be easily measured when assessing muscle components?

The five components that can be easily measured when assessing muscle components are already mentioned: muscle thickness, pennation angle, fascicle length, echo intensity and cross-sectional area. 

Q9. What is the need for a tool that can give information about both muscle quantity and quality?

There is an important need for an instrument that can give information about both muscle quantity and quality, that is cheap and easily available in routine practice, and that can be used in large populationbased screenings. 

Q10. What is the largest part of the information on the quadriceps muscle?

The largest part of information on anatomical landmarks is found on the four bellies of the quadriceps muscle (rectus femoris, vastus lateralis, vastus medialis, vastus intermedius). 

Q11. What is the way to assess muscle thickness?

It seems logical to use the thickest zone of a muscle when wanting to assess muscle thickness, as this will be the place that the muscle will generate the most contractive power.