Quantitative evaluation of adhesion severity around subscapularis and its relationship with shoulder range of motion in frozen shoulder and rotator cuff disorder: an observational study using dynamic ultrasonography.

Background: This study aimed to evaluate the severity of adhesion between muscles in the shoulder joint using dynamic ultrasonography and to confirm whether adhesions cause range of motion (ROM) restrictions. Methods: Twenty-four shoulders from 15 frozen shoulder patients and 24 shoulders from 18 rotator cuff disorder patients were enrolled. We obtained ultrasound video sequences of the subscapularis (SSC) and deltoid muscles during shoulder external rotation. The mean stretching velocities of the deltoid and SSC were subsequently analyzed using a personal computer. If adhesions occurred between both muscles, the deltoid was stretched more vigorously, and we calculated mean stretching velocity of the deltoid / SSC as adhesion severity. The coracohumeral ligament thickness was measured using the same images. Shoulder ROM was measured by using a universal goniometer. Results: The intraclass correlation coefficients (1.1) and (2.1) of the adhesion severity measurements were 0.85 and 0.91, respectively. Multiple linear regression analysis revealed that the adhesion severity is a significant predictor for external rotation ROM in the rotator cuff disorder group (R2 = 0.44, F = 10.1, P < .01, t = -2.9), while coracohumeral ligament thickness predicts ROM in the frozen shoulder group (R2 = 0.28, F = 5.5, P = .01, t = -3.0). Conclusion: The proposed method is reliable. Muscle adhesion causes ROM restriction of the shoulder joint. The primary cause of shoulder ROM restriction differed between the diagnostic groups.

Color Doppler shear wave elastography using commercial ultrasound machine with compensated transducer scanning delay.

PURPOSE: Tissue elasticity can be measured and mapped using color Doppler elastography. In a previous study, a binary pattern of shear waves was observed using a color flow imaging (CFI) system with matched pulse Doppler packet size as well as shear wave frequency and displacement condition. In the present study, we demonstrate the possibility of mapping shear wave velocity and resolving phantom elasticity using any commercial ultrasound machine without fulfilling that condition. METHODS: We derive a relation between Doppler autocorrelator integration time and the estimated flow velocity. The underlying principles behind the shear wave shadows captured by a typical modern ultrasound machine are investigated. The ultrasound machine measurement preset is calibrated to remove the effect of transducer array scanning delay in modifying the appearing wavenumber and thus correct the measurement error. RESULTS: The method was used to successfully measure the elasticity of a biological tissue-mimicking phantom and distinguish a stiff phantom from a soft phantom. CONCLUSION: Using this method, the elasticity of a biological tissue-mimicking phantom can be recovered with less strict constraint. As a result, it provides more flexibility to be implemented in common ultrasound machines. This method may be practically used to help identify tissue stiffness-related disease.

Binary Pattern Color Doppler Shear Wave Elastography.

Some studies suggested a correlation between tissue elasticity and diseases, such as Adhesive Capsulitis (AC) of the shoulder. One category of method to measure elasticity is by utilizing Doppler imaging. This paper discusses color Doppler shear wave elastography methods and demonstrated an experiment with biological tissue mimicking phantom. A simulation with binary pattern color Doppler shear wave elastography shows that wavelength of a shear wave with suggested magnitude is equal to four multiple of pitch strip in a color flow image. However, the larger amplitude changes the duty ratio and frequency of the pattern. An experiment with biological tissue mimicking Polyvinyl Alcohol (PVA) phantoms has shown that the binary pattern color Doppler method has successfully recovered shear wave velocity map and calculate the elasticity.Clinical Relevance-The result of experiments presents a possibility of using the method for quantitatively access the stage of tissue stiffness related disease.

Visualization of Shoulder Ligaments Motion by Ultrasound Speckle Tracking Method.

There is no unified consensus on the pathophysiology of adhesive capsulitis which is also called as frozen shoulder. Some studies have suggested that coracohumeral ligament (CHL) played an important role in adhesive capsulitis. These studies showed relation between disease prevalence and CHL thickness by means of ultrasound or MRI. Other possible etiology of the disease is the adhesion of shoulder ligament with each other. In the present study, shoulder ligaments motion is visualized with velocity vector by speckle tracking and temporal outlier removal algorithm to process ultrasound movie during forced movement of shoulder joint. The measurement with a typical subject has demonstrated an improvement of velocity vector deviation of up to 43% by the proposed outlier removal technique.

Biomechanics of C2C12 Cells Observed with Cellular Resolution Scanning Acoustic Microscope Combined with Optical Microscope.

Biomechanics of the cell indicates the inner structure and viability of the cell. Mechanical properties are represented by acoustic properties such as speed of sound (SOS) or acoustic impedance. In the present study, cellular resolution scanning acoustic microscope combined with optical microscope (OptSAM) is developed to observe the change of mechanical properties in cell differentiation. Main part of the OptSAM was consisted of 350 MHz ultrasound transducer mechanically scanned by a piezo-actuator. Thickness, SOS, acoustic impedance, density and elastic bulk modulus of the cell were deduced by the ultrasound responses in both time domain and frequency domain. C2C12 cell changing its form from myoblast to myotube was observed by OptSAM. The value of bulk modulus slightly increased in response to differentiation process. OptSAM non-invasively provides important information on biomechanics of cells without contact or staining.