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.

A cadaveric study on sacroiliac joint injection.

The scope of this study was to explore the possibility as well as the feasibility of sacroiliac joint injection following simple X-ray clip location. For the cadaveric study, 10 fixed sacroiliac joint (SIJ) sectional specimens, 4 dried cadaveric pelvises and 21 embalmed adult cadaveric pelvises were dissected, followed by an injection of contrast agent into the joint. The irrigation of the agent was observed through CT scanning. For the radiologic study, 188 CT scans of ankylosing spondylitis patients (143 male, 45 female) were collected from 2010 to 2012, in Nanfang Hospital. What was measured was (1) Distance between the posterior midline and sagittal synovium; (2) Length of the sagittal synovium; (3) Distance between the midpoint of the sagittal synovium and posterior superior iliac spine; and (4) Distance between the superficial skin vertical to the sagittal synovium point were measured. For the practice-based study: 20 patients (17 males and 3 females) with early ankylosing spondylitis, from Nanfang Hospital affiliated with Southern Medical University were recruited, and sacroiliac joint unguided injections were done on the basis of the cadaveric and radiologic study. Only the inferior 1/3(rd) portion parallel to the posterior midline could be injected into since the superior 2/3(rd) portion were filled with interosseous ligaments. Thirteen of the 20 patients received successful injections as identified by CT scan using the contrast agent. Sacroiliac joint injection following simple X-ray clip location is possible and feasible if the operation is performed by trained physicians familiar with the sacroiliac joint and its surrounding anatomic structures.