MicroPure imaging for the evaluation of microcalcifications in gouty arthritis involving the first metatarsophalangeal joint: a preliminary study.
OBJECTIVE
To assess the value of MicroPure, a new ultrasound image processing technique, in identifying microcalcifications (formed by monosodium urate crystals) in the first metatarsophalangeal joints attacked by gout compared to gray-scale ultrasound images.


METHODS
Thirty-six patients who fulfilled the study inclusion criteria underwent gray-scale ultrasound and MicroPure examinations of the first metatarsophalangeal joints attacked by gout. Static images of the target areas were acquired using gray-scale ultrasound and MicroPure. Two independent and blinded investigators analyzed the images to determine the number of microcalcifications and to score for image quality and artifacts.


RESULTS
The two investigators observed significantly more microcalcifications with MicroPure compared to gray-scale ultrasound (ρ<0.001). The level of agreement between the investigators consistently increased from gray-scale ultrasound to MicroPure imaging (gray-scale interclass correlation coefficient of 0.69 vs. MicroPure interclass correlation coefficient of 0.81). One investigator preferred the MicroPure image quality over gray-scale ultrasound (ρ<0.001), but the other investigator disagreed (ρ<0.001). Both investigators observed fewer artifacts with MicroPure than with gray-scale ultrasound (ρ<0.009).


CONCLUSIONS
MicroPure imaging identified significantly more microcalcifications than gray-scale ultrasound.
Department of Ultrasound, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai, China.
Lu
L
Yin
Department of Ultrasound, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai, China.
Jiaan
J
Zhu
Department of Rheumatology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital. Shanghai, China.
Qin
Q
Xue
Department of Rheumatology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital. Shanghai, China.
Niansong
N
Wang
Department of Ultrasound, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai, China.
Zhenlong
Z
Hu
Department of Ultrasound, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai, China.
Yunxia
Y
Huang
Department of Ultrasound, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai, China.
Fang
F
Liu
Department of Ultrasound, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai Institute of Ultrasound in Medicine, Shanghai, China.
Bing
B
Hu
D000328:Adult; D000368:Aged; D015210:Arthritis, Gouty / Q000000981:diagnostic imaging* / Q000378:metabolism*; D002114:Calcinosis / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008683:Metatarsophalangeal Joint / Q000000981:diagnostic imaging*; D008875:Middle Aged; D014463:Ultrasonography / Q000379:methods*; D014527:Uric Acid / Q000378:metabolism
D014527:Uric Acid