Feasibility of second-generation ultrasound contrast media in the detection of active sacroiliitis.
OBJECTIVE
To determine whether a recently available contrast-enhanced ultrasound (CEUS) technique using second-generation microbubbles allows for the detection of active sacroiliitis, and to measure CEUS enhancement depth at the dorsocaudal part of the sacroiliac (SI) joints in healthy volunteers compared with patients with sacroiliitis.


METHODS
Forty-two consecutive patients (84 SI joints) presenting with a clinical diagnosis of sacroiliitis in 50 SI joints and 21 controls (42 SI joints) were investigated by CEUS using a standardized low mechanical index ultrasound protocol. Detected vascularity was used to retrospectively measure the enhancement depth in the dorsocaudal part of the SI joints.


RESULTS
CEUS detected enhancement in all clinically active SI joints, showing an enhancement depth into the dorsal SI joint cleft of 18.5 mm (range 16-22.1), which was significantly higher compared with both inactive joints of patients (3.6 mm, range 0-12; P < 0.001) and healthy controls (3.1 mm, range 0-7.8; P < 0.001). All inactive joints were correctly classified based on a lack of deep enhancement in patients with sacroiliitis and controls (42 of 42, 100% sensitivity, 100% specificity; Cohen's kappa = 1).


CONCLUSIONS
CEUS allowed the differentiation of active sacroiliitis from inactive SI joints, and proved to be a feasible method for the detection of vascularity in clinically active sacroiliitis by showing deep contrast enhancement into the SI joints not detectable in inactive joints of patients or controls. If this technique might add information to the earlier detection of sacroiliitis, it should be addressed in further studies.
Klauser
Andrea S
AS
Medical University Innsbruck, Innsbruck, Austria. andrea.klauser@i-med.ac.at
De Zordo
Tobias
T
Bellmann-Weiler
Rosa
R
Feuchtner
Gudrun M
GM
Sailer-Höck
Michaela
M
Sögner
Peter
P
Gruber
Johann
J
D000328:Adult; D001168:Arthritis / Q000000981:diagnostic imaging*; D016022:Case-Control Studies; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008297:Male; D045423:Microbubbles; D012446:Sacroiliac Joint / Q000098:blood supply / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods
D003287:Contrast Media