Lateral Abdominal Muscles Shear Modulus and Thickness Measurements under Controlled Ultrasound Probe Compression by External Force Sensor: A Comparison and Reliability Study

Water immersion ultrasound can improve the repeatability of ultrasonic measurement of dorsalis pedis artery diameter and hemodynamic parameters

OBJECTIVE

In comparing the repeatability of the internal diameter and hemodynamic parameters of the dorsalis pedis artery measured by immersion ultrasound and contact ultrasound, the factors affecting the accuracy and repeatability of measurement were analyzed. This study aimed to provide a better method for ultrasound evaluation of the dorsalis pedis artery before flap transplantation.

METHODS

Two senior sonographers measured the diameter of the dorsalis pedis artery (D) of 56 healthy volunteers, measuring at the same location and at different time points using water immersion and contact ultrasound. Color Doppler ultrasound was used to measure the hemodynamics of the dorsalis pedis artery, including peak systolic velocity (PSV), end diastolic velocity (EDV), and resistance index (RI). The interclass correlation coefficient (ICC) was used to evaluate the intraobserver and interobserver repeatability for each group's measurements.

RESULTS

The intraobserver and interobserver reproducibility of D, PSV, EDV, and RI measurements by water immersion ultrasound was very good. The intraobserver and interobserver reproducibility of the contact ultrasound measurements of D, PSV, EDV, and RI was good.

CONCLUSION

The repeatability of water immersion ultrasound is better than that of contact ultrasound in the measurement of the dorsalis pedis artery. Water immersion ultrasound can improve the near-field resolution of superficial tissues and increase the display of the lengths of blood vessels in images, thereby suggesting its superiority in ultrasound examination of dorsalis pedis arteries.

Ultrasonic Imaging and Sensors

Ultrasound imaging is a wide research field, covering areas from wave propagation physics, sensors and front-end electronics to image reconstruction algorithms and software [...].

Intra-Rater Reliability of Shear Wave Elastography for the Quantification of Respiratory Muscles in Adolescent Athletes

The aim of this study was to assess the intra-rater reliability and agreement of diaphragm and intercostal muscle elasticity and thickness during tidal breathing. The diaphragm and intercostal muscle parameters were measured using shear wave elastography in adolescent athletes. To calculate intra-rater reliability, intraclass correlation coefficient (ICC) and Bland-Altman statistics were used. The reliability/agreement for one-day both muscle measurements (regardless of probe orientation) were at least moderate. During the seven-day interval between measurements, the reliability of a single measurement depended on the measured parameter, transducer orientation, respiratory phase, and muscle. Excellent reliability was found for diaphragm shear modulus at the peak of tidal expiration in transverse probe position (ICC_3.1 = 0.91-0.96; ICC₃.₂ = 0.95), and from poor to excellent reliability for the intercostal muscle thickness at the peak of tidal inspiration with the longitudinal probe position (ICC_3.1 = 0.26-0.95; ICC₃.₂ = 0.15). The overall reliability/agreement of the analysed data was higher for the diaphragm measurements (than the intercostal muscles) regardless of the respiratory phase and probe position. It is difficult to identify a more appropriate probe position to examine these muscles. The shear modulus/thickness of the diaphragm and intercostal muscles demonstrated good reliability/agreement so this appears to be a promising technique for their examination in athletes.

Quantitative Analysis of Abdominal Muscles Using Elastography in Female Patients With Incisional Hernia

This study aimed to assess the thickness and shear wave speed (SWS) of the anterolateral abdominal wall muscles in female patients with incisional hernias of different widths, in order to analyze the biomechanical properties of abdominal wall muscles. This study included 53 patients with incisional hernia (Group A [hernia width <4 cm]: 21 patients, Group B [hernia width ≥4 cm]: 32 patients). The muscle thickness and SWS values of the external oblique (EO), internal oblique (IO), and transversus abdominis (TrA), and the hernia width were measured using Siemens Acuson S2000 ultrasound systems. Four detection points were labeled on the anterolateral abdominal wall: points 1, 2, 3, and 4, corresponding to the upper right, upper left, lower right, and lower left, respectively. The muscle thickness of the IO at point 3 was significantly different between both groups (p = 0.024). Group B had significantly higher SWS values than Group A, especially for the EO (points 1, 2, and 3), IO (points 1 and 2), and TrA (points 2 and 4) (p < 0.05). Pearson correlation analysis shows no significant correlation between muscle thickness and the SWS values of EO, IO, and TrA (all p > 0.05). Linear correlation analysis showed a significantly positive correlation between hernia width and the mean SWS value of EO, IO, and TrA (p = 0.004, 0.005, and 0.043, respectively). Muscle thickness was not reliable measure to directly reflect the biomechanical changes of the abdominal wall muscles in patients with incisional hernia. Comparatively, SWE can accurately measure the stiffness of the abdominal wall muscles and intuitively evaluate its biomechanical properties.

Feasibility of Using a Portable MyotonPRO Device to Quantify the Elastic Properties of Skeletal Muscle

BACKGROUND The aims of this study were to (1) calculate the correlation between different tensile force levels and corresponding muscle stiffness both in vitro and in vivo; (2) determine whether muscle stiffness assessed using a MyotonPRO myotonometer can be used to accurately estimate muscle activity level; and (3) evaluate the inter-operator reliability of MyotonPRO-based measurement in assessing biceps brachii muscle (BBM) stiffness. MATERIAL AND METHODS In Experiment I, muscle stiffness, as measured using the MyotonPRO, was obtained at 0 N, 2 N, 4 N, 6 N, 8 N, and 10 N of applied force on 6 fresh medial gastrocnemius muscle specimens. In Experiment II, 11 healthy subjects were recruited. BBM stiffness, assessed by the same device, was obtained at different tensile force levels, from 0 to 50% of maximal voluntary contraction (MVC). For the reliability test, the score for each subject was quantified by 2 operators (I and II), thrice, at 30-minute intervals on the same day. RESULTS A strong correlation was found between the different tensile force levels, which corresponded to muscle stiffness in vitro (r=0.71-0.95, all P<0.05). In vivo, muscle stiffness increased linearly with an increase of the tensile force levels from 0 to 50% of MVC (r=0.99, P=0.00) and there was a significant difference in BBM stiffness among the incremental isometric tasks (F [1.76, 17.60]=91.52, P=0.00). The inter-operator reliability for the measurement of BBM stiffness was good (ICC=0.86). CONCLUSIONS Our findings indicate that muscle stiffness measured using the MyotonPRO is strongly related to muscle activity level and that the MyotonPRO is a feasible tool for quantifying BBM stiffness as well as for quantifying changes in MVC levels.

A Sarcopenia Detection System Using an RGB-D Camera and an Ultrasound Probe: Eye-in-Hand Approach

Skeletal muscle mass deficiency and quality degradation constitute sarcopenia for elderly people. Sarcopenia can result in musculoskeletal damage and accompany various metabolic problems, which make early sarcopenia diagnosis important. Various modalities, such as computed tomography (CT) and magnetic resonance imaging (MRI), have been developed for screening sarcopenia. Recently, ultrasound scanning was suggested for screening sarcopenia because of its safety, usability, and cost effectiveness. However, there has been no standardized assessment methodology for screening sarcopenia with ultrasound scanning. Therefore, prior to this study, we developed a four-degrees-of-freedom (DOF) sarcopenia detection system using an RGB-D camera and an ultrasound probe to automatically scan the human thigh without operator dependency. However, due to the eye-to-hand approach with the RGB-D camera, the system has limited usability for clinical trials. Therefore, in this study we modified the system such that it became eye-in-hand by attaching the RGB-D camera to the upper part of the system with an enhanced arc fitting algorithm. The modified system and enhanced algorithm were verified by an in-vitro test with bean curd-gelatin phantom. The results showed that the thickness of bean curd in the gelatin phantom was maintained at approximately 12.7 ± 0.35 mm over the 71.5∘ scanning range with 2.49 ± 0.15 N radial force at various thickness measuring points.