MRI of Fistula-in-Ano: A Comparison of Endoanal Coil with External Phased Array Coil Techniques

MR Imaging of Perianal Crohn Disease

“…Multichannel, external pelvic phasedarray coils have improved MR imaging acquisition quality through parallel imaging, with benefits of decreased acquisition time, increased signal-to-noise ratio, and larger fields of view, without the need for endoanal coils. While deSouza et al found better surgical concordance for detection of primary tract and internal opening by using an endoanal coil, an external pelvic phased-array coil enabled better visualization of supralevator disease, disease in the ischiorectal/ischioanal fossae, and subcutaneous extensions (28). Higher-fieldstrength 3-T magnets provide better signal-to-noise ratio with increased spatial resolution compared with 1.5-T, but to our knowledge, no direct comparison studies have been performed.…”

Surgical management of pyogenic complications of Crohnʼs disease

“…Many other studies using the endoanal coil have also shown MRI to be a sensitive technique for fistula classification, although accuracy may vary depending on a variety of factors such as technique, type of fistula, or presence of proctitis. [7][8][9] Accuracy as reported in the literature for MRI ranges from 84%-91%. [10][11][12] However, the use of the endoanal coil has obvious limitations in the Crohn's patient with severe active rectal disease or stricture in the setting of anal fistula disease.…”

MRI of Crohn?s Anoperineal Disease

“…External phased array coils represent an excellent alternative in providing high spatial resolution images with a large field of view, while avoiding the discomfort of an endoluminal coil. The larger fields of view are important for better delineation of secondary tracks and extensions [36].…”