Magnetic resonance imaging as an adjunct to planning an anorectal pull-through.

Magnetic resonance imaging (MRI) is a relatively new diagnostic tool that generates images of sections of the body taken in any plane. We report the use of MRI as a tool to plan surgical procedures in patients with imperforate anus, imaging the pelvis and lumbosacral spine in the sagittal, transverse, and coronal planes. MRI clearly reveals the extent of the pelvic musculature even in patients with severe sacral agenesis. MRI is extremely useful in assessing patients under consideration for reoperation, clearly demonstrating the relationship between the pulled through colon and the "striated muscle complex." A very useful addition is the ability, on the same study, to detect previously unsuspected anomalies such as tethered cord, lipoma of the filum terminale, and renal dysplasia. We conclude that MRI is a very useful examination in selected patients with imperforate anus.