title: Conventional ultrasound and contrast-enhanced ultrasound in evaluating the severity of Crohn's disease.
abstract: OBJECTIVE
  To evaluate the value of conventional ultrasound and contrast-enhanced ultrasound (CEUS) in determining the severity of active Crohn's disease.
  
  
  METHODS
  Thirty-seven patients who were considered to be in active period of Crohn's disease were included. Conventional ultrasound was employed to measure the thicknesses of interior, exterior and the whole bowel walls. Qualitative and quantitative CEUS analysis of the interior, exterior and the whole intestinal walls were also performed. Correlations between these methods and the severity of Crohn's disease were assessed.
  
  
  RESULTS
  Endoscopy grading system identified 19 patients with mild disease and 18 with severe disease. In discriminating severe Crohn's disease from mild disease, the cut-off value for the thickness of the entire bowel wall was 6.8 mm by receiver operating characteristic (ROC) analysis, with area under ROC (AUROC) of 0.84, sensitivity of 94.4%, specificity of 68.4%, positive predictive value (PPV) of 61.1%, negative predictive value (NPV) of 69.2%, and Youden's index of 0.628. The cut-off value for thickness of the interior intestinal wall was 4.8 mm (AUROC, 0.81; sensitivity, 88.9%; specificity, 63.2%; PPV, 85.7%; NPV, 69.6%; Youden's index, 0.521). The sensitivity, specificity, PPV, NPV, accuracy, and Youden's index of CEUS qualitative analysis were 100% (18/18), 57.9% (11/19), 64.3% (18/26), 100% (11/11), 78.4% (29/37), and 0.579, respectively. Quantitative comparison revealed that patients with mild disease and those with severe disease differed only in Imax of inner bowel wall enhancement (2746.9 ± 911 vs. 12814.5 ± 9802.4; P = 0.02) and Imax of entire wall enhancement (2106 ± 660 vs. 9864 ± 6994; P = 0.03). The cut-off value for the Imax of the entire bowel wall was 3067, with the AUROC of 0.96, sensitivity of 100%, specificity of 67.7%, PPV of 100%, NPV of 88.9%, and Youden's index of 0.677; and the cut-off value for the Imax of the interior intestinal layer was 3356, with the AUROC of 1.00, sensitivity of 100%, specificity of 100%, PPV of 100%, NPV of 100%, and Youden's index of 1.0.
  
  
  CONCLUSIONS
  Both conventional ultrasound and CEUS are reliable methods in determining the severity of active Crohn's disease. The diagnostic performance in terms of Youden's index was highest for the Imax of the interior layer, in comparison with all other features on conventional ultrasound, qualitative CEUS, and quantitative CEUS.
authors.affiliation: Department of Medical Ultrasound, Shanghai Tenth People's Hospital, Tenth People's Hospital of Tongji University Shanghai, China.
authors.forename: Chang
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Gastroenterology, Shanghai Tenth People's Hospital, Tenth People's Hospital of Tongji University Shanghai, China.
authors.forename: Xiao-Rong
authors.initials: XR
authors.lastname: Xu
authors.affiliation: Department of Medical Ultrasound, Shanghai Tenth People's Hospital, Tenth People's Hospital of Tongji University Shanghai, China.
authors.forename: Hui-Xiong
authors.initials: HX
authors.lastname: Xu
authors.affiliation: Department of Gastroenterology, Shanghai Tenth People's Hospital, Tenth People's Hospital of Tongji University Shanghai, China.
authors.forename: Zhan-Ju
authors.initials: ZJ
authors.lastname: Liu
authors.affiliation: Department of Medical Ultrasound, Shanghai Tenth People's Hospital, Tenth People's Hospital of Tongji University Shanghai, China.
authors.forename: Yi-Feng
authors.initials: YF
authors.lastname: Zhang
authors.affiliation: Department of Medical Ultrasound, Shanghai Tenth People's Hospital, Tenth People's Hospital of Tongji University Shanghai, China.
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Sun
authors.affiliation: Department of Medical Ultrasound, Shanghai Tenth People's Hospital, Tenth People's Hospital of Tongji University Shanghai, China.
authors.forename: Jun-Mei
authors.initials: JM
authors.lastname: Xu
authors.affiliation: Department of Medical Ultrasound, Shanghai Tenth People's Hospital, Tenth People's Hospital of Tongji University Shanghai, China.
authors.forename: Lin-Na
authors.initials: LN
authors.lastname: Liu
authors.affiliation: Department of Medical Ultrasound, Shanghai Tenth People's Hospital, Tenth People's Hospital of Tongji University Shanghai, China.
authors.forename: Le-Hang
authors.initials: LH
authors.lastname: Guo
authors.affiliation: Department of Medical Ultrasound, Shanghai Tenth People's Hospital, Tenth People's Hospital of Tongji University Shanghai, China.
authors.forename: Xiao-Wan
authors.initials: XW
authors.lastname: Bo
keywords: Crohn’s disease; contrast-enhanced ultrasound; conventional ultrasound; qualitative analysis; quantitative analysis