Roy Soendersing Dwarkasing MD, Abstract Co-Author: Nothing to Disclose

Tychon Geeraedts, Presenter: Nothing to Disclose

Wim Hop PHD, , Abstract Co-Author: Nothing to Disclose

Ruud Schouten MD, PhD, Abstract Co-Author: Nothing to Disclose

Gabriel P. Krestin MD, PhD, Abstract Co-Author: Consultant, General Electric Company Research grant, General Electric Company Research grant, Bayer AG Research grant, Siemens AG

To assess the diagnostic performance of dedicated MRI in patients with persistent anal and perianal pain and without abnormalities found in the clinical work up.

Patients referred from the surgical department for colorectal diseases to the MRI unit were reviewed regarding symptoms, indication for MRI, findings in the clinical work up and final diagnosis. The search criteria were anal and perianal pain more than 3 months and no causes found in the clinical work up including examination under general anaesthesia and anorectoscopy. In case the patient was previously treated for anorectal diseases the disease free period should be at least 1 year. MRI was performed using an endoanal or pelvic phased array coil with complete view of the pelvis and anal canal with T2 weighted sequences in 3 planes. All examinations were read by 2 abdominal radiologists.

The study group (n = 101, mean 49 years) was stratified in 2 groups; patients with history of anorectal diseases (group 1, n= 44) and  without (group 2, n= 57). MRI indicated the final diagnoses in 43 %, including perianal fislulae (n=18), fistulae with abscess (n=2),  abscesses (n=10), painfull scarring of the anal sphincter (n= 12), metastasis to the sacrum (n=1). All fistulae and abscesses (n=30) were surgically proven; metastasis to the sacrum was biopsy proven (n=1). Scarring of the sphincter muscles was demonstrated by MRI and assessed clinically as the causative substrate (n=12). In the remaining patients with no abnormalities on MRI the final diagnoses were painful pelvic syndrome (n=38), chronic pain e.c.i. (n=26). Both readers has excellent agreement (kappa value 0.98). MRI demonstrated statistically more abnormalities in group 1 (64 %) compared to group 2 (26%) (p<0.001, Chi-square tests). The PPV of MRI was 90 %; NPV 100 %.    

MRI will demonstrate a physical cause in 43 % of all patients with persistent anal and perianal pain and no abnormalities found in the clinical work up. Statistically more abnormalities were found in patients with a history of anorectal diseases. The most encountered abnormality is perianal fistula disease, including absesses and painfull scar tissue of the anal sphincter muscles. 

Dedicated MRI of the anorectum should be considered in patients with persistent anal and perianal pain before these patients are regarded a functional pain syndrome

Dwarkasing, R, Geeraedts, T, Hop, W, Schouten, R, Krestin, G, MRI Evaluation of Patients with Anal and Perianal Pain Referred to a Tertiary Colorectal Surgical Department.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11014717.html