Magnetic Resonance Imaging (MRI) Characterization of Perianal Fistulous Disease in a Rural Based Tertiary Hospital of North India

Abstract

SummaryBackgroundTo diagnose and characterize the perianal fistulous disease using Magnetic resonance imaging (MRI) in a hilly and rural area of North India.Material/MethodsThis prospective hospital based study was conducted for a period of one year from April 2014 to April 2015 in the departments of Radiodiagnosis and Surgery of our institute. A total of 50 consecutive patients presenting with perianal fistulous disease fulfilling the inclusion and exclusion criteria were included in the study and taken up for MRI. The perianal fistulae were classified according to St James University hospital classification and tracks were assessed with regard to anatomical plane, length, ramifications, abscess formation, enteric communication, external cutaneous opening, enhancement and suprasphincteric extension. Surgical correlation was done in 31 patients who opted for surgical treatment. Rest of the 19 patients preferred alternative medicine for treatment or chose to postpone their surgery.ResultsThe disease was much more prevalent in males in comparison to females with male to female ratio of 24:1. Grade 4 was the most common type of fistula (34%) while Grade 5 was the least common type (4%).MRI showed a high sensitivity of 93.7% and positive predictive value (PPV) of 96.7% when correlated with surgical findings. A substantial number of patients (38%) preferred alternative medicine or non surgical form of treatment.ConclusionsMRI is a very sensitive modality for the evaluation of perianal fistula. In our study group, the disease predominantly affected middle aged men. Ramifications and abscesses were commonly seen, affecting nearly half of the patients and majority of the patients had active fistulous tracks with posteriorly located enteric opening. Overall, transsphincteric fistulae were most common. Significant number of patients avoided surgery or showed preference for non surgical treatment.

The treatment of anal fistula: secondACPGBIPosition Statement – 2018

“…Several groups have devised grading systems based on MRI. The St James’ system relates to the fistula anatomy and shows good concordance with surgical findings . Van Assche et al .…”

“…Several groups have devised grading systems based on MRI. The St James' system relates to the fistula anatomy [75] and shows good concordance with surgical findings [76]. Van Assche et al [77] have developed a MRI scoring system which includes assessment of the type and number of tracks, the presence and type of extensions, collections and rectal wall thickening and the signal intensity on T2-weighted scans.…”

Preoperatif manyetik rezonans görüntülemenin anal fistül tanı ve cerrahi tedavisine katkısı

“…Few studies have pointed out the false-negative results of the MR imaging 24,27,28 . MR imaging failed to identify two fistulae tracts and two internal openings in our study.…”

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

“…In line with these findings, Singh et al [18] reported high sensitivity of MRI in identification of secondary tract, correct localization of internal opening, and correct detection of horse-shoeing with rates of 93.75%, 95.83%, and 87.5%, respectively. Also, Chauhan et al [19] reported that MRI showed a high sensitivity rate of 93.7% and positive predictive value (PPV) of 96.7% when correlated with surgical findings. Recently, Karanikas et al [20] reported a success rate of 77.4% to demonstrate the presence of a fistula in their series DW-MRI, in comparison to the other pulse sequences, 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.…”