Verification of palpation-guided intra-articular injections using glucocorticoid-air-saline mixture and ultrasound imaging (GAS-graphy).

OBJECTIVE: To examine a contrast medium method using a glucocorticoid-air-saline mixture and ultrasound imaging (GAS-graphy) for the verification of palpation-guided injections in different joints and to assess the inter-reader reliability of the method. METHODS: A palpation-guided injection of an air-steroid-saline mixture was given into a joint or tendon sheath of 133 consecutive patients. The dynamic ultrasound monitor images of the joints and tendons involved were videotaped before and after the injection. A rheumatologist and two radiologists analyzed separately the video clips of each patient, under blinded conditions. The readers evaluated the accuracy of the injections and the difficulty of the reading process. The inter-reader agreement was assessed by calculating the percentual values and overall kappa coefficient between the readers. RESULTS: The overall accuracy of the successful injections was 76%, 80% and 82 % evaluated by the three readers. In six out of the ten injection sites the accuracy was higher than 80%. The clarity of the method evaluated by the readers was 8, 8 and 8.5 on a scale from 0 to 10. The inter-reader agreement assessed by percentual values was 84.2%, 85.0% and 88.7%. The kappa coefficient between all readers was 0.595 showing moderate agreement. CONCLUSION: The GAS-graphy method for the verification of palpation-guided injections is a simple procedure performable to any joint site and the result can be seen immediately on the monitor after the injection. The reliability of the method is good and it can be used in developing injection techniques as well as in medical or nurse education. The method can be used as an alternative for the radiographic contrast medium method in verifying successful palpation-guided intra-articular injections.

Use of air-steroid-saline mixture as contrast medium in greyscale ultrasound imaging: experimental study and practical applications in rheumatology.

OBJECTIVES: To investigate experimentally the echogenicity of air, a steroid suspension and physiological saline mixed with water in order to find the best contrast medium for injections. To show the practical applications of an airsteroid-saline mixture as a contrast medium in rheumatology. METHODS: In vitro. First, quality assurance measurements were conducted twice on the ultrasound (US) equipment. Subsequently air, a steroid suspension, or physiological saline mixed with water, first alone and then in different combinations, were examined with US using quantitative image analysis. Clinical. The effectiveness of an air-steroid-saline mixture as contrast medium in ultrasonography was tested in joint, bursa and tendon sheath injections. RESULTS: In vitro. Based on the quality assurance measurements the physical performance of the US equipment was excellent. Verified visually and quantitatively the mixture of air, steroid and saline produced the best contrast on US. The importance of air bubbles producing contrast was obvious. Clinical application. Firstly, visualisation of the contrast medium with US made it possible to follow in real-time the passage of a drug to the target area. Secondly, the use of the contrast method verified the presence of steroid in the synovial target intended after a blind injection. Thirdly, anatomical and pathologic anatomical connections could be visualized using this contrast medium in the wrist, shoulder, knee, ankle and foot joint CONCLUSIONS: Verification of US system performance by quality assurance measurement is essential for US imaging. The air-steroid-saline contrast medium method of ultrasound scanning is a somewhat invasive, but inexpensive and rapid method. It can verify the existence or non-existence of an air-steroid-saline contrast medium in the desired place and in adjacent structures, thus showing possible pathologic anatomic connections. The method has a diagnostic and therapeutic value, and expands the interventional spectrum of sonographic imaging.