Identification of surgically-induced longitudinal lesions of the equine deep digital flexor tendon in the digital flexor tendon sheath using contrast-enhanced ultrasonography: an ex-vivo pilot study

Equine flexor tendon imaging part 1: Recent developments in ultrasonography, with focus on the superficial digital flexor tendon

Flexor tendon injuries are a major cause of lameness in performance horses and have considerable impact on equine welfare and the wider horse industry. Ageing and repetitive strain frequently cause varying degrees of tendon micro-damage prior to the recognition of clinical tendinopathy. Whilst B-mode ultrasonography is most commonly utilised for detection and monitoring of tendon lesions at the metacarpal/metatarsal level, the emphasis of recent research has focused on the identification of subclinical tendon damage in order to prevent further tendon injury and improve outcomes. The introduction of elastography, acoustoelastography and ultrasound tissue characterisation in the field of equine orthopaedics shows promising results and might find wider use in equine practice as clinical development continues. Based on the substantial number of research studies on tendon imaging published over the past decade this literature review aims to examine the currently used ultrasonographic imaging techniques and their limitations, and to introduce and critically appraise new modalities that could potentially change the clinical approach to equine flexor tendon imaging.

Assessment of intrasynovial injection in horses by contrast-enhanced ultrasonography using air bubbles created by agitation of solution

BACKGROUND

Accuracy of intrasynovial injections can be challenging to assess in a clinical setting in horses. Contrast-enhanced ultrasonography (CEUS) using injectate agitated with air has been used to determine the success rates of synovial injections in human rheumatology.

OBJECTIVES

To assess the diagnostic sensitivity and specificity of CEUS and to describe its clinical use.

STUDY DESIGNS

Cadaveric study followed by a prospective descriptive observational study.

METHODS

Part 1: CEUS was performed following injection of agitated methylene-blue solution targeting 13 different anatomical synovial structures from three equine cadavers. Contrast was seen as hyperechoic dots, patches or lines on ultrasonography. CEUS was classified as positive if contrast was considered to be intrasynovial and negative if contrast was considered to be extrasynovial. A second synoviocentesis was performed to determine if the injection was intrasynovial based on the presence or absence of methylene-blue. Estimates of sensitivity and specificity were calculated. Part 2: CEUS was performed following injection of agitated solutions targeting synovial structures as part of routine investigation and treatment of clinical cases.

RESULTS

Part 1: CEUS was correctly classified as positive or negative in all intrasynovial and extrasynovial injections respectively. The sensitivity estimate was 100% (CI 93%-100%) and the specificity estimates was 100% (CI 16%-100%). Part 2: The technique was used safely for 26 injections (14 horses; 19 different synovial structures) administered to localise or treat lameness. Traumatic intersynovial communications or synovial membrane defects were identified using CEUS in 3 horses.

MAIN LIMITATIONS

The low number of extrasynovial injections in Part 1 resulted in an imprecise specificity estimate.

CONCLUSIONS

In horses, CEUS performed following intended intrasynovial injection can be useful for identifying unsuccessful injections.

The Value of Percutaneous Shoulder Puncture with Contrast-enhanced Ultrasound in Differentiation of Rotator Cuff Tear Subtypes: A Preliminary Prospective Study

Imaging tests perform relatively well in the detection of rotator cuff tears (RCTs), exhibiting high sensitivity and specificity, mainly among larger full-thickness tears (tear width >1 cm). However, these tests are relatively less accurate in the detection of small full-thickness tears and partial-thickness tears. The purpose of this study was to determine the feasibility of percutaneous ultrasound-guided tendon lesionography (PUTL) using the SonoVue and the value of percutaneous shoulder puncture via contrast-enhanced ultrasound (CEUS)-a combination of percutaneous ultrasound-guided subacromial bursography (PUSB) and PUTL-in the detection of RCT subtypes. Conventional ultrasound (US), CEUS and magnetic resonance imaging (MRI) were performed and prospectively evaluated in 97 patients who had undergone arthroscopy because of suspected RCTs. The rates of detection of the various subtypes of RCTs using CEUS, PUSB, PUTL, US and MRI were evaluated. The RCT subtype detection rate via CEUS was significantly higher than the rates via US and MRI (96.9%, 74.2% and 76.3%, respectively), as were the detection rates for small full-thickness tears combined with partial-thickness tears (98.2%, 60.0% and 61.8%, respectively). The detection rate with PUSB was significantly higher than those with US and MRI in assessing full-thickness tears combined with bursal-side partial-thickness tears (93.9%, 65.3% and 65.3%, respectively). The detection rate with PUTL was significantly higher than those with US and MRI in assessing the corresponding subtypes (100.0%, 69.2% and 76.9%, respectively). On the basis of our findings, we consider PUTL a tolerable and feasible procedure. Percutaneous shoulder puncture using CEUS can be an effective alternative method with better diagnostic performance than US and MRI for the detection of RCT subtypes.