Intrasession and interrater reliability of rehabilitative ultrasound imaging measures of the deep neck flexors: A pilot study

A Procedure for Measuring Anterior Scalene Morphology and Quality with Ultrasound Imaging: An Intra- and Inter-rater Reliability Study

OBJECTIVE

Ultrasound (US) imaging is an essential tool for clinicians because of its cost-effectiveness and accessibility for assessing multiple muscle metrics including muscle quality, size and shape. Although previous studies highlighted the importance of the anterior scalene muscle (AS) in patients with neck pain, studies analyzing the reliability of US measurements for this muscle are lacking. This study aimed to develop a protocol for assessing AS muscle shape and quality measured with US and investigating its intra- and inter-examiner reliability.

METHODS

Through use of a linear transducer, B-mode images of the anterolateral neck region at the C7 level were acquired in 28 healthy volunteers by two examiners (one experienced and one novel). Cross-sectional area, perimeter, shape descriptors and mean echo-intensity were measured twice by each examiner in randomized order. Intra-class correlation coefficients (ICCs), standard errors of measurement and minimal detectable changes were calculated.

RESULTS

Results indicated no muscle side-to-side asymmetries (p > 0.05). Gender differences were found for muscle size (p < 0.01), but muscle shape and brightness were comparable (p > 0.05). Intra-examiner reliability was good to excellent for all metrics for the experienced and (ICC >0.846) and novel (ICC >780) examiners. Although inter-examiner reliability was good for most of the metrics (ICC >0.709), the estimates for assessing solidity and circularity were unacceptable (ICC <0.70).

CONCLUSION

This study found that the described ultrasound procedure for locating and measuring anterior scalene muscle morphology and quality is highly reliable in asymptomatic individuals.

Musculoskeletal diagnostic ultrasound imaging for thickness measurement of four principal muscles of the cervical spine -a reliability and agreement study

BACKGROUND

The reliability of musculoskeletal diagnostic ultrasound imaging (MSK-DUSI) for the evaluation of neck musculature has been sparsely documented in the research literature. Until now, research has featured a limited number of subjects and only few studies have tested for both inter- and intra-reliability using appropriate methodology.

METHODS

Four examiners conducted an inter- and intra-rater reliability and agreement study. Fifty females with and without neck pain (NP) between the ages of 20-70 were recruited from October 2014 to April 2015. The muscles that were evaluated were the longus colli (Lcol), the rectus capitis posterior major (Rcpm), the deep cervical extensors (Dce) and the semispinalis capitis (Sscap). Each of the examiners captured ultrasound images of their allocated muscle and measured the thickness of that muscle twice, on separate occasions, for the first part of the intra-rater reliability study. For the second part, a second image of the same muscle was taken on the same subject and measured by the same examiner. The four examiners then met to measure on each other's images, to test inter-rater reliability. Their results were compared pair-wise using Interclass Correlation Coefficients (ICC) and Bland-Altman plots. Linear regression analysis was performed to evaluate for possible bias.

RESULTS

Inter-rater reliability was found to be good for Lcol and Sscap muscles and moderate towards poor for the deeper Rcpm and Dce muscles. Intra-rater reliability was good for all the muscles, with the exception of the Dce, which was found to be moderate in the second part of the study. The B&A plots showed good agreement, few outliers, and no bias. However, the agreement intervals indicated a measurement error within the variance of the method that may not have been acceptable for these small muscles if the aim is to evaluate change in thickness.

CONCLUSIONS

This study found that MSK-DUSI had variable reliability in assessing the thickness of the Lcol, Rcpm, Dce, and Sscap muscles. No bias was demonstrated, but agreement intervals were wide.

Reliability of a measurement method for the cross-sectional area of the longus colli using real-time ultrasound imaging

OBJECTIVE

Real-time ultrasound imaging is an established objective outcome measurement with proven reliability. However, it is still largely biased by user-ability. Published research in the area of real-time ultrasound imaging reliability in the cervical region and in particular the deep cervical flexors is quite sparse. The purpose of this investigation was to examine if a novice ultrasound user could agree favourably with an experienced ultrasound sonographer in measuring the cross-sectional area of the longus colli.

METHODS

Ultrasound images were captured from 22 healthy subjects on two different occasions, one week apart, by a novice ultrasound user. They were acquired using a GE Healthcare LOGIQe ultrasound machine, at a depth of 3-4 cm with the transducer frequency set to 8 MHz, in line with previous research guidelines. Cross-sectional area was then measured on-screen by both a novice and experienced ultrasound user to determine inter-rater reliability. Intra-rater reliability was also analysed using cross-sectional area figures from days one and two.

RESULTS

Intra-rater reliability for real-time ultrasound imaging for the cross-sectional area of the longus colli was "excellent" (intra-class correlation 0.90, 95% CI 0.82-0.95). Inter-rater reliability was "moderate" but in keeping with previous published research (intra-class correlation 0.61, 95% CI 0.37-0.77).

CONCLUSION

Difficulties in identifying the borders of the longus colli muscle due to its deep anatomical location and surrounding structures make it difficult for assessors to agree favourably on cross-sectional area measurements, leading to "moderate" levels of inter-rater reliability and poor agreement. Intra-rater reliability is excellent, and in this instance indicates that a novice user can be just as reliable as a more experienced ultrasound user.

Inter-rater, intra-rater, and inter-machine reliability of quantitative ultrasound measurements of the patellar tendon

The use of ultrasound (US) to perform quantitative measurements of musculoskeletal tissues requires accurate and reliable measurements between investigators and ultrasound machines. The objective of this study was to evaluate inter-rater and intra-rater reliability of patellar tendon measurements between providers with different levels of US experience and inter-machine reliability of US machines. Sixteen subjects without a history of knee pain were evaluated with US examinations of the patellar tendon. Each tendon was scanned independently by two investigators using two different ultrasound machines. Tendon length and cross-sectional area (CSA) were obtained, and examiners were blinded to each other's results. Tendon length was measured using a validated system involving surface markers and calipers, and CSA was measured using each machine's measuring software. Intra-class correlation coefficients (ICCs) were used to determine reliability of measurements between observers, where ICC > 0.75 was considered good and ICC > 0.9 was considered excellent. Inter-rater reliability between sonographers was excellent and revealed an ICC of 0.90 to 0.92 for patellar tendon CSA and an ICC of 0.96 for tendon length. ICC for intra-rater reliability of tendon CSA was also generally excellent, with ICC between 0.87 and 0.96. Inter-machine reliability was excellent, with ICC of 0.91-0.98 for tendon CSA and 0.96-0.98 for tendon length. Bland-Altman plots were constructed to measure validity and demonstrated a mean difference between sonographers of 0.03 mm(2) for CSA measurements and 0.2 mm for tendon length. Using well-defined scanning protocols, a novice and an experienced musculoskeletal sonographer attained high levels of inter-rater agreement, with similarly excellent results for intra-rater and inter-machine reliability. To our knowledge, this study is the first to report inter-machine reliability in the setting of quantitative musculoskeletal ultrasound.