P232 Real-time Shear Wave Ultrasound Elastography in distinguishing inflammatory from fibrotic stenosis in Crohn's disease
Y.-j. Chen*1, R. Mao2, Y. He2, B.-l. Chen2, Z.-r. Zeng2, X.-y. Xie1, M.-h. Chen2
1First Affiliated Hospital of Sun Yat-sen University, Department of Medical Ultrasonics, Guangzhou, China, 2First Affiliated Hospital of Sun Yat-Sen University, Department of Gastroenterology, Guangzhou, China
Differentiation between inflammatory and fibrotic strictures in Crohn's disease (CD) is difficult but crucial for therapeutic decisions. Prior work has demonstrated that ultrasound elastography imaging (UEI) can identify intestinal ﬁbrosis in animal models of CD. The purpose of our study was to determine if real-time shear wave elastography (SWE), a new technique of UEI can be used to distinguish inflammatory from fibrotic strictures in CD patients.
A total of one hundred and twenty established CD patients underwent transcutaneous UEI by the technique of real-time SWE using the ultrasound system, Aixplorer (SuperSonic Imagine S.A., Aix-en-Provence, France). Thickened bowel wall and proximal normal bowel were analyzed by measuring Young's Modulus (YM) of the tissue. According to a formalized score combining endoscopy, CT/MR enterography and histology, strictures were classified as inflammatory and fibrotic stenosis. One-way ANOVA and Bonferroni were used for statistical analysis, and receiver operating characteristic (ROC) curves were created to assess diagnostic performance.
YM was measured successfully in one hundred and ten CD patients(male n=40, female n=70; mean age 40y, range 13y-65y,). These 110 patients were divided into three groups: acute inﬂammatory non-stenotic (n=46), inﬂammatory stenosis (n=44) and ﬁbrotic stenosis group (n=20), with the value of YM as 15.5 ± 6.7 KPa, 16.7 ± 5.7 KPa, and 25.8 ± 8.0 KPa respectively. Transcutaneous UEI demonstrated YM was higher in ﬁbrotic stenosis than inﬂammatory stenosis ( P=0.016) and acute inﬂammed non-stenotic group (P=0.015). No significant difference existed between acute inﬂammatory stenosis and acute inﬂamnatory non-stenotic bowel (P>0.05). The most accurate cut-off value for distinguishing inflammatory from fibrotic stenosis was 17.5 KPa, achieving 98% of sensitivity and 71.4% of specificity. The area under the receiver operating characteristic curve (AUC) was 0.883（95% CI: 0.84-0.93）.
UEI provides a noninvasive new method in distinguishing inflammatory from fibrotic strictures in CD patients, and may thereby be helpful in guiding therapeutic decisions.