Is Magnetic Resonance Imaging Superior to Conventional Radiography in Neonates with Anorectal Malformation?

Abstract

Introduction This study was conducted to evaluate the role of magnetic resonance imaging (MRI) in neonates with anorectal malformation (ARM). Materials and Methods Newborns, referred to Pediatric Surgical Ward through General Surgery Outpatient Department and Emergency Department of Sir Sunderlal Hospital as a case of ARM, were included in the study. Unstable patients requiring urgent primary colostomy were excluded from the study. Forty neonates with ARM and 20 neonates having no ARM were included in the study ( 2 years, i.e., conducted between September 2018 and July 2020). The included patients were evaluated clinically and were subjected to an invertogram (after 24 hours of delivery), which is conventional radiography. Further, MRI was performed using 1.5 T superconductive system; 5 to 6 mm contiguous sections were obtained using a head or a body coil according to the size of the infant patient to obtain images with sharp anatomical detail: Sagittal, coronal, and axial conventional spin-echo T1-weighted images of the pelvic region were obtained in all patients, with perpendicular coronal plane and the axial plane parallel to pelvic floor. Results The majority of patients (60%) were referred on day 3 of birth and rest were referred after 3 days of birth. Conventional radiography, that is, invertogram was done in all study population. Sixty per cent of the total included patients had supralevator location of rectal pouch. Conventional radiography was detected to be low type of ARM—all had infralevator position of rectal pouch in MRI, but 60% of the intermediate had supralevator level and all high abnormalities had supralevator level. These distribution anomalies were statistically significant. The levator ani length index and external anal sphincter length index were also compared and found to be thickest in intermediate type, thick in low types, and thin in high type of abnormalities, which is an added advantage of MRI over radiography. Conclusion Preoperative assessment of ARM with MRI gives useful information regarding type of malformation as well as sphincter muscle and associated malformations. Large sample size was needed for future landmark in the field of ARM.

Keywords

• anorectal malformation
• invertogram
• mri
• sphincter muscle complex
• external anal sphincter
• vacterl