Use of air-steroid-saline mixture as contrast medium in greyscale ultrasound imaging: experimental study and practical applications in rheumatology.
OBJECTIVE
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.
Koski
J M
JM
Mikkeli Central Hospital, Mikkeli, Finland. f.koski@fimnet.fi
Saarakkala
S J
SJ
Heikkinen
J O
JO
Hermunen
H S
HS
D000388:Air; D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging; D003287:Contrast Media; D005938:Glucocorticoids; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007596:Joints / Q000000981:diagnostic imaging; D011785:Quality Assurance, Health Care; D015203:Reproducibility of Results; D012219:Rheumatology / Q000379:methods*; D012965:Sodium Chloride; D014463:Ultrasonography / Q000379:methods* / Q000592:standards
D003287:Contrast Media; D005938:Glucocorticoids; D012965:Sodium Chloride