American Journal of Roentgenology, Vol 173, 723-728, Copyright © 1999 by American Roentgen Ray Society
Transanal MR imaging after repair of anorectal anomalies in children: appearances in pull-through versus posterior sagittal reconstructions
NM deSouza, HC Ward, AD Williams, M Battin, DN Harris and DK McIver
Department of Radiology, Hammersmith Hospital, London, England.
OBJECTIVE: Our objective was to use transanal MR imaging to compare the
anatomic appearance of the components of the anal sphincter and the pattern
of scarring after a pull-through perineoplasty versus a posterior sagittal
anorectoplasty. SUBJECTS AND METHODS: Sixteen children ranging in age from
10 months to 15 years (mean, 10 years) were imaged using transanal receiver
coils appropriate to the size of the child. Five had low, four
intermediate, and seven high anomalies. Seven had undergone a transanal
pull-through procedure, and nine had undergone posterior sagittal
reconstruction. The integrity of the muscles was assessed on T1-weighted
and short inversion time inversion recovery transverse and coronal images
using a qualitative MR imaging score. The pattern of scarring was also
assessed. RESULTS: In the transanal pull-through group, four of seven
patients showed external sphincter deficiency. A circumferential
low-signal-intensity band was seen inferior to the sphincter in six
patients. All posterior sagittal reconstructions had a long posterior
midline scar. Five of nine patients showed external sphincter deficiency,
whereas a further two had internal sphincter deficiency. No differences
were seen in MR imaging scores for each operative procedure for all grades
of severity of anorectal anomaly. However, a comparison between high and
intermediate anomalies showed a small improvement in MR imaging score using
the transanal pull-through procedure (Mann-Whitney U test = 3, p < .03).
Manometric pressures obtained in 13 patients were poor. CONCLUSION:
Transanal MR imaging identifies focal defects and patterns of scarring of
the anal sphincter complex in infants and children and provides valuable
information about individual muscle components.