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

Vo, Duc; Phan, Chien Cong; Nguyen, Linh; Le, Huyen; Nguyen, Tin Dao; Pham, Hung

doi:10.1038/s41598-019-54441-2

Cited by 31 publications

(29 citation statements)

References 15 publications

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“…The key determinant of success in fistula surgery is the radiological assessment. The availability of MRI and transrectal ultrasound (TRUS) have greatly enhanced the understanding of anal fistulas[ 27 ]. The importance of preoperative assessment of the fistula with MRI or TRUS cannot be overemphasized.…”

Section: Discussionmentioning

confidence: 99%

Lessons learned from an audit of 1250 anal fistula patients operated at a single center: A retrospective review

Garg¹,

Kaur²,

Goyal³

et al. 2021

WJGS

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BACKGROUND A complex anal fistula is a challenging disease to manage. AIM To review the experience and insights gained in treating a large cohort of patients at an exclusive fistula center. METHODS Anal fistulas operated on by a single surgeon over 14 years were analyzed. Preoperative magnetic resonance imaging was done in all patients. Four procedures were performed: fistulotomy; two novel sphincter-saving procedures, proximal superficial cauterization of the internal opening and regular emptying and curettage of fistula tracts (PERFACT) and transanal opening of intersphincteric space (TROPIS), and anal fistula plug. PERFACT was initiated before TROPIS. As per the institutional GFRI algorithm, fistulotomy was done in simple fistulas, and TROPIS was done in complex fistulas. Fistulas with associated abscesses were treated by definitive surgery. Incontinence was evaluated objectively by Vaizey incontinence scores. RESULTS A total of 1351 anal fistula operations were performed in 1250 patients. The overall fistula healing rate was 19.4% in anal fistula plug ( n = 56), 50.3% in PERFACT ( n = 175), 86% in TROPIS ( n = 408), and 98.6% in fistulotomy ( n = 611) patients. Continence did not change significantly after surgery in any group. As per the new algorithm, 1019 patients were operated with either the fistulotomy or TROPIS procedure. The overall success rate was 93.5% in those patients. In a subgroup analysis, the overall healing rate in supralevator, horseshoe, and fistulas with an associated abscess was 82%, 85.8%, and 90.6%, respectively. The 90.6% healing rate in fistulas with an associated abscess was comparable to that of fistulas with no abscess (94.5%, P = 0.057, not significant). CONCLUSION Fistulotomy had a high 98.6% healing rate in simple fistulas without deterioration of continence if the patient selection was done judiciously. The sphincter-sparing procedure, TROPIS, was safe, with a satisfactory 86% healing rate for complex fistulas. This is the largest anal fistula series to date.

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Section: Discussionmentioning

confidence: 99%

Lessons learned from an audit of 1250 anal fistula patients operated at a single center: A retrospective review

Garg¹,

Kaur²,

Goyal³

et al. 2021

WJGS

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“…The sensitivity and specificity for abscesses were 100%. A simultaneous comparison of T2W TSE (turbo spin echo) and post-contrast T1W TSE sequences revealed the latter to be more sensitive but the former to be more specific for internal opening and secondary tracks [53]. In another prospective study, apart from showing a high sensitivity and specificity for diagnosing fistula track (98.6% and 99.7%) and identification of internal opening (97.7% and 98.6%), MRI also added significant information in 46.7% cases regarding parameters of complexity, thus establishing its role as an important pre-operative imaging tool for fistula-in-ano [54].…”

Section: Discussionmentioning

confidence: 99%

Current imaging techniques for evaluation of fistula in ano: a review

Sharma

Yadav

Sahu

et al. 2020

Egypt J Radiol Nucl Med

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Background: Fistula in ano is one of the common anorectal disorders which have a tendency to recur specially in complex cases usually due to missed or undetected sepsis at the time of examination or surgery. A correct identification of the primary source of crypt infection along with a complete understanding of the anatomical course of primary and secondary tracks and abscesses is a prerequisite for the successful management of fistula. Preoperative evaluation of fistula in ano using radio-imaging techniques provides a handy insight of fistula anatomy and helps in planning the appropriate treatment strategy. The objective of this article is to review the role of different radio-imaging techniques in the diagnosis and evaluation of fistula in ano along with their advantages and disadvantages over one another. Main text: A comprehensive literature review was performed searching through the electronic databases as well as the standard textbooks of colorectal surgery. X-rays (plain radiographs and contrast fistulography), computed tomography (CT) scanning, anal endosonography, and magnetic resonance (MR) imaging are the modalities used for preoperative imaging of fistula in ano. Due to low accuracy, X-ray fistulography is not used now for fistula imaging. CT fistulography can be more accurate in cases associated with acute inflammations and abscesses and the fistulas related with inflammatory bowel disease. Anal endosonography and MRI are two of the mostly used and reliable imaging techniques for fistula in ano. Though the use of a 3D technology has improved the accuracy of anal endosonography, MRI is the preferred choice by many. However, various reports have depicted comparable accuracies for both MRI and anal endosonography showing both to be equally sensitive but MRI to be more specific. 3D endoanal ultrasound, on the other hand, is more rapid and can also be used intraoperatively to provide live imaging during surgical exploration. Conclusion: Complex and recurrent fistula cases should undergo a preoperative imaging to reduce the chances of recurrence. MRI is recommended as the imaging modality of choice for such cases. 3D anal endosonography may however be a good option over MRI owing to its rapidity, availability, and potential of intraoperative assistance during surgery.

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“…Combined T2W TSE and postcontrast fat sat T1W TSE sequences had high sensitivity (96.6% and 98.4%, respectively) and specificity (92.6% and 81.5%, respectively) for depicting internal openings and secondary tracts, and postcontrast T1 FS TSE sequence was 100% accurate in delineating abscesses. 11 In our study, we compared plain MRI study including axial T1W, axial and coronal oblique T2 W and T2 FS images with postcontrast axial, coronal, and sagittal T1 FS TSE images. We found that T2 and T2FS images were sufficient to make the diagnosis of fistulas as well as their complications in all 30 patients (100%).…”

Section: Discussionmentioning

confidence: 99%

Magnetic Resonance Imaging of Perianal Fistulas in Clinically Symptomatic Patients and the Correlation Among Plain, Contrast, and Post Jelly MRI Fistulography

Gupta

Kumar

et al. 2021

Journal of Coloproctology

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Objectives To evaluate different types of perianal fistulas and their complications on magnetic resonance imaging (MRI) and to compare plain, contrast, and jelly magnetic resonance fistulography findings. Materials and Methods This prospective study was performed in 30 patients who presented with perianal pus discharge or external fistulous opening. Magnetic resonance imaging of the perianal region before and after giving intravenous contrast and after injecting jelly through a percutaneous opening was performed on a 3T scanner and the results were correlated. Results The mean age of the patients was 40.13 ± 13.88 years (range 19–75 years). The male to female ratio was 14:1. The most common type of fistula was St. James classification type I, which was seen in 13 patients (43%), followed by type IV in 30%, type III in 16%, type II in 6.66%, and type V in 3.33% of the patients. Using agreement analysis, we compared the number of primary and secondary tracts, internal openings, and horseshoe tracts and found a significant agreement between plain and post Jelly MRI fistulography (kappa statistic close to 1). When comparing plain and contrast MRI, there was significant agreement in the primary and secondary tracts, while statistically insignificant results were obtained (p > 0.05) for the horseshoe tract and internal openings. Contrast injection was helpful in 7 subjects (23.3%) as peripheral enhancement of abscesses were better delineated. Conclusion Magnetic resonance imaging is the one stop diagnostic modality for perianal fistulas. Acquisition of axial (Ax) T2, axial T2 FS, coronal T2 and coronal T2 FS sequences without administering intravenous contrast or jelly is usually sufficient for the diagnosis of fistulas and their complications.

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

Cited by 31 publications

References 15 publications

Lessons learned from an audit of 1250 anal fistula patients operated at a single center: A retrospective review

Lessons learned from an audit of 1250 anal fistula patients operated at a single center: A retrospective review

Current imaging techniques for evaluation of fistula in ano: a review

Magnetic Resonance Imaging of Perianal Fistulas in Clinically Symptomatic Patients and the Correlation Among Plain, Contrast, and Post Jelly MRI Fistulography

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