Role of Diffusion-Weighted Imaging in the Evaluation of Perianal Fistulae
Background Magnetic resonance imaging (MRI) is the imaging modality of choice for evaluating perianal fistulae, due to its ability to show the relationship of perianal fistulae with anal sphincters, fistula extensions, secondary ramifications and associated complications.
Aim To evaluate the role of diffusion-weighted MRI in the evaluation of perianal fistulae.
Settings and Design A hospital-based cross-sectional study.
Materials and Methods The study group composed of 47 patients of perianal fistula. MRI with diffusion-weighted imaging (DWI) was performed with Philips 0.5 T Ingenia scanner. DWI with different b-values (b = 50, b = 400, and b = 800 smm2) were obtained. The MRI findings were correlated with local clinical examination and or surgical findings.
Statistical Analysis Used Chi-square test, independent samples t-test, and receiver operating characteristic curve analysis.
Result Fifty-nine perianal fistulas in 47 patients were included in the study sample. The visibility of perianal fistula on DWI was less than T2-weighted (T2W) and combined DWI-T2W images. Distinctly visualized (visibility score 2) perianal fistulas were observed in 47 fistulas (79.6%) on DWI, 54 (91.5%) on T2W, and 58 (98.3%) on DWI-T2W images. The mean of apparent diffusion coefficient (ADC) values of active fistula was 0.972 ± 0.127 [SD] 10−3 mm2/s and inactive was 1.232 ± 0.185 [SD] 10−3 mm2/s with a significant difference (p-value < 0.0005). A cut-off mean ADC value of 1.105 × 10−3 mm2/s was used to differentiate active from the inactive fistula with a sensitivity of 87.5% and specificity of 73.3%.
Conclusion Combined DWI-T2W evaluation had a better performance in the detection of fistula than DWI or T2W alone. DWI with mean ADC calculation had a good performance in differentiating active from the inactive fistulas.
23. Mai 2021 (online)
© 2021. Indian Radiological Association. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).
Thieme Medical and Scientific Publishers Private Ltd.
A-12, Second Floor, Sector -2, NOIDA -201301, India
- 1 Zanotti C, Martinez-Puente C, Pascual I, Pascual M, Herreros D, García-Olmo D. An assessment of the incidence of fistula-in-ano in four countries of the European Union. Int J Colorectal Dis 2007; 22 (12) 1459-1462
- 2 Alabiso ME, Iasiello F, Pellino G. et al. 3D-EAUS and MRI in the activity of anal fistulas in Crohn’s disease. Gastroenterol Res Pract 2016; 2016: 1895694
- 3 de Miguel Criado J, del Salto LG, Rivas PF. et al. MR imaging evaluation of perianal fistulas: spectrum of imaging features. Radiographics 2012; 32 (01) 175-194
- 4 George U, Sahota A, Rathore S. MRI in evaluation of perianal fistula. J Med Imaging Radiat Oncol 2011; 55 (04) 391-400
- 5 Halligan S, Stoker J. Imaging of fistula in ano. Radiology 2006; 239 (01) 18-33
- 6 Buchanan GN, Halligan S, Bartram CI, Williams AB, Tarroni D, Cohen CR. Clinical examination, endosonography, and MR imaging in preoperative assessment of fistula in ano: comparison with outcome-based reference standard. Radiology 2004; 233 (03) 674-681
- 7 Buchanan G, Halligan S, Williams A. et al. Effect of MRI on clinical outcome of recurrent fistula-in-ano. Lancet 2002; 360 (93/46) 1661-1662
- 8 Yoshizako T, Wada A, Takahara T. et al. Diffusion-weighted MRI for evaluating perianal fistula activity: feasibility study. Eur J Radiol 2012; 81 (09) 2049-2053
- 9 Hori M, Oto A, Orrin S, Suzuki K, Baron RL. Diffusion-weighted MRI: a new tool for the diagnosis of fistula in ano. J Magn Reson Imaging 2009; 30 (05) 1021-1026
- 10 Dohan A, Eveno C, Oprea R. et al. Diffusion-weighted MR imaging for the diagnosis of abscess complicating fistula-in-ano: preliminary experience. Eur Radiol 2014; 24 (11) 2906-2915
- 11 Tomar V, Yadav A, Rathore RK. et al. Apparent diffusion coefficient with higher b-value correlates better with viable cell count quantified from the cavity of brain abscess. AJNR Am J Neuroradiol 2011; 32 (11) 2120-2125
- 12 Mohsen LA, Osman NM. Diffusion-weighted imaging in the evaluation of perianal fistula and abscess. Egypt J Radiol Nucl Med 2020; 51: 71
- 13 Cavusoglu M, Duran S, Sözmen Cılız D. et al. Added value of diffusion-weighted magnetic resonance imaging for the diagnosis of perianal fistula. Diagn Interv Imaging 2017; 98 (05) 401-408
- 14 Wang Y, Gu C, Huo Y. et al. Diffusion tensor imaging for evaluating perianal fistula: feasibility study. Medicine (Baltimore) 2018; 97 (29) e11570
- 15 Bakan S, Olgun DC, Kandemirli SG. et al. Perianal fistula with and without abscess: assessment of fistula activity using diffusion-weighted magnetic resonance imaging. Iran J Radiol 2015; 12 (04) e29084
- 16 Berman L, Israel GM, McCarthy SM, Weinreb JC, Longo WE. Utility of magnetic resonance imaging in anorectal disease. World J Gastroenterol 2007; 13 (23) 3153-3158
- 17 Panes J, Bouhnik Y, Reinisch W. et al. Imaging techniques for assessment of inflammatory bowel disease: joint ECCO and ESGAR evidence-based consensus guidelines. J Crohn’s Colitis 2013; 7 (07) 556-585
- 18 Maccioni F, Colaiacomo MC, Stasolla A, Manganaro L, Izzo L, Marini M. Value of MRI performed with phased-array coil in the diagnosis and pre-operative classification of perianal and anal fistulas. Radiol Med (Torino) 2002; 104 (1-2) 58-67
- 19 Beets-Tan RG, Beets GL, van der Hoop AG. et al. Preoperative MR imaging of anal fistulas: does it really help the surgeon?. Radiology 2001; 218 (01) 75-84
- 20 Khera PS, Badawi HA, Afifi AH. MRI in perianal fistulae. Indian J Radiol Imaging 2010; 20 (01) 53-57
- 21 Yoshizako T, Kitagaki H. A pictorial review of the impact of adding diffusion-weighted MR imaging to other MR sequences for assessment of anal fistulae. Jpn J Radiol 2013; 31 (06) 371-376
- 22 Morris J, Spencer JA, Ambrose NS. MR imaging classification of perianal fistulas and its implications for patient management. Radiographics 2000; 20 (03) 623-635, discussion 635–637