The use of beam angulation to overcome anisotropy when viewing human tendon with high frequency linear array ultrasound

Reliability of coracohumeral distance and subcoracoid tendons in subacromial pain syndrome

This study investigated the intra-rater reliability of a novice ultrasound (US) examiner and the inter-rater reliability of two examiners (novice, expert) in the measures of coracohumeral distance at rest (CHD) and at 60° of elevation without (CHD60) or with weights (CHD60w), tendon thickness of the long head of the biceps (LHB) and subscapularis (SCP). Twenty-one patients with subacromial pain syndrome (SAPS) and 20 asymptomatic participants were included. Intra and inter-rater reliability were tested with intraclass-correlation-coefficient (ICC), differences between raters were analyzed with Bland-Altman plots. Intra-rater reliability for CHD, CHD60 and CHD60w was excellent (ICC = 0.97-0.98) in asymptomatic participants, and good-to-excellent (0.88-0.93) in SAPS, while intra-rater reliability for LHB and SCP was good-to-excellent in asymptomatic participants (0.88-0.97) and in SAPS (0.90-0.92). Inter-rater reliability for CHD, CHD60 and CHD60w was moderate-to-good (0.70-0.90) in asymptomatic participants and good (0.85-0.87) in SAPS, in contrast inter-rater reliability for LHB and SCP was poor in asymptomatic participants (0.10-0.46) and poor-to-moderate (0.49-0.61) in SAPS. Bland-Altman plots revealed systematic and/or proportional bias for tendons' thickness. A novice showed good-to-excellent intra-rater reliability in all US measures, whereas in comparison to an expert a novice can measure reliably CHD, CHD60 and CHD60w, but not LHB and SCP, where more training is recommended.

High-Resolution Ultrasonographic Anatomy of the Carpal Tendons of Sporting Border Collies

Recent literature has demonstrated that high-resolution ultrasonographic anatomy of the canine carpus is possible; however, only the structures of the dorsal face were described. The aims of this prospective study were: (1) to describe the normal ultrasonographic appearance of the carpal tendons in sporting Border Collies; (2) to measure the height, length, and thickness of the tendon at the radial ulnar notch level in order to create a baseline reference for the breed, and (3) to describe a standardised protocol to ultrasonographically evaluate the carpal faces and visible tendinous structures. A pilot study based on ten cadaveric front limbs was used to identify the structures. A subsequent clinical phase of the study using twenty-six Border Collies was recorded. The tendons of the Extensor Carpi Radialis, Extensor Digitorum Communis, and Extensor Digitorum Lateralis were identified and followed from the tenomuscular junction to the distal insertion on the dorsal face of the digits. On the lateral face, the tendon of the Extensor Carpi Ulnaris was recognised and followed. On the palmar face, the two heads of the Flexor Carpi Ulnaris tendon ending on the accessory carpal bone, the adjacent Flexor Digitorum Superficialis tendon, and the deep and medially located Flexor Digitorum Profundus tendon were seen and followed. The Flexor Carpi Radialis and the Abductor Pollicis Longus tendons were seen in the medial carpal face. The ulnar notch of the radius was used as the measurement and starting point of the ultrasonography. These data could be used as a standard reference in the case of chronic overuse and trauma-induced changes in the canine carpus.

Diagnostic and therapeutic musculoskeletal ultrasound applications of the shoulder

High frequency ultrasound is a valuable tool for assessing soft tissue injuries about the shoulder. It has advantages over other imaging modalities including relatively low cost, portability, and dynamic real-time visualization. It has a high sensitivity for identifying tendon degeneration, bursitis, and rotator cuff tears. Ultrasound is also an excellent modality for diagnostic and therapeutic needle-guided procedures. A detailed knowledge of shoulder anatomy and transducer positioning is required for obtaining adequate diagnostic value from ultrasound. This Monograph is designed to help develop scanning protocols for optimizing image acquisition for musculoskeletal assessment of the shoulder. Muscle Nerve, 2019.

Elasticity standard values of the Achilles tendon assessed with acoustic radiation force impulse elastography on healthy volunteers: a cross section study

Background

To determine normal values for acoustic radiation force impulse (ARFI) shear wave elastography of the Achilles tendon.

Methods

Using the VTIQ mode with the Acuson S3000™ (Siemens Healthcare, Erlangen, Germany), we measured the shear wave velocity (SWV) in m/s and the diameter in mm of both Achilles tendons in 182 healthy volunteers. The tendon was displayed in a sagittal view with a relaxed tendon. The parameters were tested for correlations with the anthropometric data of the subjects, between the genders and different age groups, as well as information obtained from the history, such as smoking and sporting activities.

Results

Using a sagittal acoustic window, we determined a mean SWV of 9.09 ± 0.71 m/s for the left Achilles tendon and 9.17 ± 0.61 m/s for the right. There was a significant difference between the results for the right and left side (p < 0.05). The diameter on the left was 4.7 ± 0.9 mm. On the right, it was 4.8 ± 0.9 mm. Likewise there was a significant difference between the results for the diameter of the left and right side (p < 0.05). Neither gender, body mass index (BMI) nor age had a significant effect on either of the measured parameters (p > 0.05). The same goes for the consumption of tobacco and alcohol (p > 0.05).

Conclusions

Age, gender, BMI, smoking or the consumption of alcohol did not affect either the elasticity or the diameter of the Achilles tendon.

Nonconfocal all-optical laser-ultrasound and photoacoustic imaging system for angle-dependent deep tissue imaging

Biomedical imaging systems incorporating both photoacoustic (PA) and ultrasound capabilities are of interest for obtaining optical and acoustic properties deep in tissue. While most dual-modality systems utilize piezoelectric transducers, all-optical systems can obtain broadband high-resolution data with hands-free operation. Previously described reflection-mode all-optical laser-ultrasound (LUS) systems use a confocal source and detector; however, angle-dependent raypaths are lost in this configuration. As a result, the overall imaging aperture is reduced, which becomes increasingly problematic with depth. We present a reflection-mode nonconfocal LUS and PA imaging system that uses signals recorded on all-optical hardware to create angle-dependent images. We use reverse-time migration and time reversal to reconstruct the LUS and PA images. We demonstrate this methodology with both a numerical model and tissue phantom experiment to image a steep-curvature vessel with a limited aperture 2-cm beneath the surface. Nonconfocal imaging demonstrates improved focusing by 30% and 15% compared to images acquired with a single LUS source in the numerical and experimental LUS images, respectively. The appearance of artifacts is also reduced. Complementary PA images are straightforward to acquire with the nonconfocal system by tuning the source wavelength and can be further developed for quantitative multiview PA imaging.

A User Guide to Compound Imaging

Compound imaging is now available on several high-end ultrasound scanners. It takes different forms and refers to different methods of creating the ultrasound image. The aim of this article is to familiarize the reader with simple background information about how it works, and to provide a clinician's view of how, why and when to use it.

Ultrasonic assessment of extracellular matrix content in healing Achilles tendon

Although several imaging modalities have been utilized to observe tendons, assessing injured tendons by tracking the healing response over time with ultrasound is a desirable method which is yet to be realized. This study examines the use of ultrasound for non-invasive monitoring of the healing process of Achilles tendons after surgical transection. The overall extracellular matrix content of the transection site is monitored and quantified as a function of time. B-mode images (built from successive A-scan signatures) of the injury site were obtained and compared to biomechanical properties. A quantitative measure of tendon healing using the extracellular matrix (ECM) content of the injury site was analyzed using linear regression with all biomechanical measures. Contralateral tendons were used as controls. The trend in the degree of ECM regrowth in the 4 weeks following complete transection of excised tendons was found to be most closely paralleled with that of linear stiffness (R(2) = 0.987, p < .05) obtained with post-ultrasound biomechanical tests. Results suggest that ultrasound can be an effective imaging technique in assessing the degree of tendon healing, and can be used to correlate structural properties of Achilles tendons.

Asymptomatic Achilles tendon pathology is associated with a central fat distribution in men and a peripheral fat distribution in women: a cross sectional study of 298 individuals

Background

Adiposity is a modifiable factor that has been implicated in tendinopathy. As tendon pain reduces physical activity levels and can lead to weight gain, associations between tendon pathology and adiposity must be studied in individuals without tendon pain. Therefore, the purpose of this study was to determine whether fat distribution was associated with asymptomatic Achilles tendon pathology.

Methods

The Achilles tendons of 298 individuals were categorised as normal or pathological using diagnostic ultrasound. Fat distribution was determined using anthropometry (waist circumference, waist hip ratio [WHR]) and dual-energy x-ray absorptiometry.

Results

Asymptomatic Achilles tendon pathology was more evident in men (13%) than women (5%) (p = 0.007). Men with tendon pathology were older (50.9 ± 10.4, 36.3 ± 11.3, p < 0.001), had greater WHR (0.926 ± 0.091, 0.875 ± 0.065, p = 0.039), higher android/gynoid fat mass ratio (0.616 ± 0.186, 0.519 ± 0.142, p = 0.014) and higher upper-body/lower body fat mass ratio (2.346 ± 0.630, 2.022 ± 0.467, p = 0.013). Men older than 40 years with a waist circumference >83 cm had the greatest prevalence of tendon pathology (33%). Women with tendon pathology were older (47.4 ± 10.0, 36.0 ± 10.3, p = 0.008), had less total fat (17196 ± 3173 g, 21626 ± 7882 g, p = 0.009), trunk fat (7367 ± 1662 g, 10087 ± 4152 g, p = 0.003) and android fat (1117 ± 324 g, 1616 ± 811 g, p = 0.005). They had lower central/peripheral fat mass ratios (0.711 ± 0.321 g, 0.922 ± 0.194 g, p = 0.004) than women with normal tendons. Women with tendon pathology were more often menopausal (63%, 13%, p = 0.002).

Conclusions

Men with Achilles tendon pathology were older and had a central fat distribution. Women with tendon pathology were older and had a peripheral fat distribution. An interaction between age and waist circumference was observed among men.

Tendinopathy discrimination by use of spatial frequency parameters in ultrasound B-mode images

The structural characteristics of a healthy tendon are related to the anisotropic speckle patterns observed in ultrasonic images. This speckle orientation is disrupted upon damage to the tendon structure as observed in patients with tendinopathy. Quantification of the structural appearance of tendon shows promise in creating a tool for diagnosing, prognosing, or measuring changes in tendon organization over time. The current work describes a first step taken towards this goal-classification of Achilles tendon images into tendinopathy and control categories. Eight spatial frequency parameters were extracted from regions of interest on tendon images, filtered and classified using linear discriminant analysis. Resulting algorithms had better than 80% accuracy in categorizing tendon image kernels as tendinopathy or control. Tendon images categorized wrongly provided for an interesting clinical association between incorrect classification of tendinopathy kernels as control and the symptom and clinical time history based inclusion criteria. To assess intersession reliability of image acquisition, the first 10 subjects were imaged twice during separate sessions. Test-retest of repeated measures was excellent (tau = 0.996, ICC = (2, 1) = 0.73 with one outlier) indicating a general consistency in imaging techniques.

Extensor Retinaculum of the Wrist: Sonographic Characterization and Pseudotenosynovitis Appearance

OBJECTIVE

We have found in our practice that the normal extensor retinaculum of the wrist may appear hypoechoic on sonography and, because it is closely applied to the extensor tendons, may simulate tenosynovitis. This study prospectively evaluates the extensor retinaculum in 50 healthy adult volunteers, characterizing its sonographic appearance.

CONCLUSION

The extensor retinaculum has a characteristic appearance on sonography. A hypoechoic appearance from anisotropy should not be confused with tenosynovitis.

ULTRASONOGRAPHIC ANATOMY OF THE NORMAL CANINE CALCANEAL TENDON

To provide a series of detailed ultrasonographic images of the canine calcaneal tendon, greyhound cadaver pelvic limbs were scanned with a high-resolution transducer, and images compared with dissected specimens. The three components of the calcaneal tendon are the tendons of insertion of the gastrocnemius, superficial digital flexor, and a conjoined tendon formed by tendons from the biceps femoris, semitendinosus, and gracilis. Each of these three tendons was visible in transverse ultrasound images, each measuring 2.4-3.2-mm thick at mid-calcaneal tendon. Improved understanding of the anatomy of the calcaneal tendon will support clinical ultrasonography of this region.

Musculoskeletal ultrasound

Over the last few years a sonographic revolution has occurred in rheumatology. Ultrasonography has been shown to be capable of substantially changing the traditional approach to most clinical problems in daily rheumatological practice because of its ability to allow a quick, safe and inexpensive access to otherwise undetectable anatomical information on the early targets of most rheumatic diseases. Ultrasonography completes the physical examination in a rapid and accurate manner and allows the detection of a wide spectrum of pathological findings involving different anatomical structures in the musculoskeletal system. Guidance for intervention (joint aspiration, synovial or soft tissue biopsy, joint or tendon sheath injection) is a major application of ultrasonography. Sonographic guidance is particularly useful when fluid collections are very small or when the inflammatory process is adjacent to anatomical structures that could be seriously damaged by the injection.