Comparison of T2-weighted imaging, diffusion-weighted imaging and contrast-enhanced T1-weighted MR imaging for evaluating perianal fistulas

This study aimed to determine the role of magnetic resonance imaging (MRI) in diagnosing and describing the characteristics of fistula-in-ano, and the agreement between MRI and operative findings. We conducted a retrospective study in 367 patients with fistula-in-ano who were diagnosed and had an operation at the University Medical Center between January 2016 and January 2018. MRI findings were evaluated and compared with surgical findings using the kappa coefficient (k) method. 367 patients (327 male and 40 female, mean age 39.3 ± 12.4 years). A total of 411 primary fistulas were found during surgery. There was a strong agreement between MRI and surgery for classifying primary tracts (k = 0.89) and detecting secondary tracts (k = 0.94). While the sensitivity and specificity of MRI for detecting internal openings were 99% and 85.2% respectively; these rates were 100% for abscesses. Both T2-weighted turbo spin-echo (T2W TSE) and postcontrast fat-saturated T1-weighted turbo spin-echo (FS T1W TSE) sequences showed high sensitivity (96.6% and 98.4% respectively) and specificity (92.6% and 81.5% respectively) for depicting internal openings and secondary tracts. Post-contrast FS T1W TSE sequence was very effective in detecting abscesses with an accuracy of 100%. In conclusion, MRI can be considered an accurate tool for the preoperative evaluation of fistula-in-ano, which is a major determinant of the surgical outcome. Both T2W TSE and post-contrast FS T1W TSE sequences are highly accurate in depicting the features of fistula-in-ano. If there are no contraindications, contrast administration is recommended to differentiate abscesses from active inflammation.

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“…Most of the patients in our study had a single primary tract (90.7%), which was similar to the previous study by Baik et al . (83%) 19 .…”

Section: Discussionmentioning

confidence: 99%

The role of magnetic resonance imaging in the preoperative evaluation of anal fistulas

Phan

Nguyen

et al. 2019

Sci Rep

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“…No direct comparison can be made with this study, as we did not categorise the fistulas as active or inactive and used fully quantitative DCE parameters; however, it highlights the strength of combining MRI quantitative parameters for improved diagnostics. DWI sequences have recently been studied for the evaluation of fistulae [20,[37][38][39]. In a retrospective study involving 24 patients with 41 lesions (23 active lesions and 18 inactive perianal fistulae) [20], the mean value for ADC in the active perianal fistula group (0.908 ± 0.171 × 10 −3 mm 2 /s) was significantly lower than for the inactive group (1.124 ± 0.244 × 10 −3 mm 2 /s).…”

Section: Discussionmentioning

confidence: 99%

Quantitative Magnetic Resonance Imaging in Perianal Crohn’s Disease at 1.5 and 3.0 T: A Feasibility Study

et al. 2021

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Perianal Crohn’s Disease (pCD) is a common manifestation of Crohn’s Disease. Absence of reliable disease measures makes disease monitoring unreliable. Qualitative MRI has been increasingly used for diagnosing and monitoring pCD and has shown potential for assessing response to treatment. Quantitative MRI sequences, such as diffusion-weighted imaging (DWI), dynamic contrast enhancement (DCE) and magnetisation transfer (MT), along with T2 relaxometry, offer opportunities to improve diagnostic capability. Quantitative MRI sequences (DWI, DCE, MT and T2) were used in a cohort of 25 pCD patients before and 12 weeks after biological therapy at two different field strengths (1.5 and 3 T). Disease activity was measured with the Perianal Crohn’s Disease Activity index (PDAI) and serum C-reactive protein (CRP). Diseased tissue areas on MRI were defined by a radiologist. A baseline model to predict outcome at 12 weeks was developed. No differences were seen in the quantitative MR measured in the diseased tissue regions from baseline to 12 weeks; however, PDAI and CRP decreased. Baseline PDAI, CRP, T2 relaxometry and surgical history were found to have a moderate ability to predict response after 12 weeks of biological treatment. Validation in larger cohorts with MRI and clinical measures are needed in order to further develop the model.

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“…Then, Yoshizako et al [21] who assessed the feasibility of using DW-MRI for evaluating perianal fistula activity documented that DW-MRI is a feasible method for evaluating perianal fistula activity with area under the ROC curve of 0.749. Thereafter, Cavusoglu et al [23] documented that DW-MRI has a significant added value compared to T2-WI alone in the diagnosis of perianal fistula and Baik et al [24] found combined DW-MRI and CE-T1WI might improve fistula conspicuity with comparable diagnostic performance to T2WI. Recently, Wang et al [25] reported that fractional anisotropy (FA) and ADC values for positive inflammation activity were significantly lower than those for negative inflammatory activity and concluded that FA and ADC values were instrumental in evaluating the activity of perianal fistulas.…”

Section: Discussionmentioning

confidence: 99%

Preoperative MRI of perianal fistula evaluation and its impact on surgical outcome

Algazzar

Eldib

Zaher

2019

Egypt J Radiol Nucl Med

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Background: Perianal fistula (PAF) is an abnormal tract communicating an external cutaneous opening in the perianal region to the anal canal. PAF is one of the common anorectal disorders in surgical practice with high prevalence. The current study aimed to determine the ability of preoperative MRI for preoperative evaluation of perianal fistula. Results: This is a retrospective evaluation of 65 patients with perianal fistula. MRI fistula imaging-related data were revised, and fistula severity was scored using criteria of both local extension of fistulas and active inflammation for a total maximum score of 22. Preoperative MRI could predict the severity of perianal disease with sensitivity, specificity, and accuracy rates of 75%, 92%, and 84.6%, respectively. Surgical findings concerning PAF severity correlated significantly with MRI findings. Diffusion-weighted magnetic resonance imaging (DW-MRI) provided high sensitivity and accuracy with 100% specificity for fistula visualization and highest sensitivity, specificity, and accuracy for detection of cavities > 3 mm in diameter. DW-MRI provided the highest specificity rate on ROC curve analysis among the three MRI pulse sequences (DW-MRI, short tau inversion recovery (STIR), and T1 post-contrast). Conclusion: MRI is valuable and accurate for preoperative investigation for PAF evaluation and abscess localization. MRI allowed accurate detection of internal fistula opening and its relation to sphincters. DW-MRI is a valuable sequence with highest diagnostic yield, and its addition to STIR WI improves sensitivity and specificity for determination of fistula activity and extension.

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Comparison of T2-weighted imaging, diffusion-weighted imaging and contrast-enhanced T1-weighted MR imaging for evaluating perianal fistulas

Cited by 25 publications

References 29 publications

The role of magnetic resonance imaging in the preoperative evaluation of anal fistulas

The role of magnetic resonance imaging in the preoperative evaluation of anal fistulas

Quantitative Magnetic Resonance Imaging in Perianal Crohn’s Disease at 1.5 and 3.0 T: A Feasibility Study

Preoperative MRI of perianal fistula evaluation and its impact on surgical outcome

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