Postoperative MR evaluation of the neorectum in patients with congenital anorectal malformations

Five patients with an original diagnosis of supralevator anal atresia had fecal incontinence following pull-through procedures. The imaging evaluation initially included barium enema and MR studies. Perineal electrostimulation data were also obtained. MR imaging was performed with a 1.5-T system. A tuberculin syringe filled with chloral hydrate was inserted into the neorectum to serve as a high-signal-intensity lumen marker. T1-weighted images were obtained in the sagittal, coronal, and axial planes with a spin-echo pulse sequence 60/20 (repetition time msec). The neorectum was determined to be centrally positioned or eccentrically placed within the external anal sphincter and puborectalis muscles. Prospectively, MR imaging accurately indicated the position of the neorectum relative to the sphincteric muscular complex. Perineal electrostimulation data were concordant with MR findings in all patients. Barium enema was helpful in one patient with rectal stricture at the pull-through site. The authors discuss how MR imaging of the postoperative neorectum in patients with fecal incontinence provides useful information in planning the surgical revision