title: Efficiency of quantitative echogenicity for investigating supraspinatus tendinopathy by the gray-level histogram of two ultrasound devices.
abstract: OBJECTIVE
  The gray-level histogram of ultrasound is a promising tool for scanning the hypoechogenic appearance of supraspinatus tendinopathy, and the aim of this study was to test the hypothesis that the gray-level value of the supraspinatus tendon in the painful shoulder has a lower value on B-mode images even though in different ultrasound devices.
  
  
  METHODS
  Sixty-seven patients who had unilateral shoulder pain with rotator cuff tendinopathy underwent bilateral shoulder ultrasonography, and we compared the mean gray-level values of painful shoulders and contralateral shoulders without any pain in each patient using two ultrasound devices. The echogenicity ratio (symptomatic/asymptomatic side) of two ultrasound devices was compared.
  
  
  RESULTS
  A significant difference existed between the symptomatic shoulder and contralateral asymptomatic shoulder (p < 0.001) on the mean gray-level value measurements of each device. The symptomatic-to-asymptomatic tendon echogenicity ratio of device A was 0.919 ± 0.090 in the transverse plane and 0.937 ± 0.081 in the longitudinal plane, and the echogenicity ratio of device B was 0.899 ± 0.113 in the transverse plane and 0.940 ± 0.113 in the longitudinal plane.
  
  
  CONCLUSIONS
  The decline of the mean gray-level value and the echogenicity ratio of the supraspinatus tendon in the painful shoulder may be utilized as a useful sonographic reference of unilateral rotator cuff lesions.
  
  
  METHODS
  Diagnostic level III.
authors.affiliation: Department of Orthopaedic Surgery, Chang Gung Memorial Hospital at Chia-Yi, No. 6, West Sec, Chia-Pu Road, Putz city, Chia-Yi county, 613, Taiwan, ROC.
authors.forename: Jiun-Cheng
authors.initials: JC
authors.lastname: Hsu
authors.affiliation: Department of Orthopaedic Surgery, Chang Gung Memorial Hospital at Chia-Yi, No. 6, West Sec, Chia-Pu Road, Putz city, Chia-Yi county, 613, Taiwan, ROC.
authors.forename: Po-Han
authors.initials: PH
authors.lastname: Chen
authors.affiliation: Department of Orthopaedic Surgery, Chang Gung Memorial Hospital at Chia-Yi, No. 6, West Sec, Chia-Pu Road, Putz city, Chia-Yi county, 613, Taiwan, ROC.|College of Medicine, Chang Gung University at Taoyuan, Taoyuan city, Taiwan, ROC.
authors.forename: Kuo-Chin
authors.initials: KC
authors.lastname: Huang
authors.affiliation: Department of Orthopaedic Surgery, Chang Gung Memorial Hospital at Chia-Yi, No. 6, West Sec, Chia-Pu Road, Putz city, Chia-Yi county, 613, Taiwan, ROC. orma2244@adm.cgmh.org.tw.|College of Medicine, Chang Gung University at Taoyuan, Taoyuan city, Taiwan, ROC. orma2244@adm.cgmh.org.tw.
authors.forename: Yao-Hung
authors.initials: YH
authors.lastname: Tsai
authors.affiliation: Department of Orthopaedic Surgery, Chang Gung Memorial Hospital at Chia-Yi, No. 6, West Sec, Chia-Pu Road, Putz city, Chia-Yi county, 613, Taiwan, ROC.|College of Medicine, Chang Gung University at Taoyuan, Taoyuan city, Taiwan, ROC.
authors.forename: Wei-Hsiu
authors.initials: WH
authors.lastname: Hsu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017006:Rotator Cuff / Q000000981:diagnostic imaging*; D000070636:Rotator Cuff Injuries / Q000000981:diagnostic imaging*; D012782:Shoulder / Q000000981:diagnostic imaging*; D020069:Shoulder Pain / Q000209:etiology; D052256:Tendinopathy / Q000150:complications / Q000000981:diagnostic imaging*; D014463:Ultrasonography / Q000295:instrumentation* / Q000379:methods; D055815:Young Adult
keywords: Gray-level; Histogram; Quantitative ultrasound; Supraspinatus