The consistency of transcutaneous perianal ultrasonography and pelvic magnetic resonance in assessing perianal lesions of Crohn's disease

Abstract

Objective To analyze the consistency of transcutaneous perianal ultrasonography (TPUS) and pelvic magnetic resonance imaging (MRI) in diagnosing perianal lesions of Crohn's disease (CD), and to evaluate the value of transcutaneous perianal ultrasonography in detecting perianal lesions of CD. Methods A cohort of 102 patients diagnosed as Corhn's disease were enrolled from August 2008 to August 2010. Perianal abscess and fistula of these CD patients was diagnosed by ultrasonography and MRI system. Statistics was performed with SPSS 11.5 software for X2 test. The consistency was analyzed with Kappa test. Results The mean onset time of perianal lesions in CD was -0.443 year (95％CI:-1.659～0.773 year) before typical symptoms showed up. There was no significant difference in detecting perianal lesions of CD between transcutaneous perianal ultrasonography and pelvic magnetic resonance imaging (P ＝ 0.706, Kappa ＝ 0.541). If pelvic magnetic resonance imaging was considered as the golden standard in detecting perianal lesions of CD,the sensitivity (Sen), specificity (Spe), Youden's index, positive predictive value (PPV) and negative predictive value (NPV) of TPUS were 72.73％, 82.61％, 0.55, 66.67％ and 86.36％ respectively.Furthermore, there was no significant difference between transcutaneous perianal ultrasonography and pelvic magnetic resonance imaging in detecting perianal abscess ( P ＝ 0.706, Kappa ＝ 0.496) and fistula (P＝0.655, Kappa＝0.546) of CD. Conclusions Perianal lesions occur in the entire course of CD. There was favorable consistency between transcutaneous perianal ultrasonography and pelvic magnetic resonance imaging in detecting perianal abscess and fistula of CD. Transcutaneous perianal ultrasonography can be used as an additional method in detecting and evaluting perianal lesions of CD. Key words: Ultrasonography; Crohn's disease; Anusdiseases; Abscess; Rectal fistula; Magnetic resonance imaging; Pelvis