Hirschsprung disease and hypoganglionosis in adults: radiologic findings and differentiation.

PURPOSE

To retrospectively evaluate the imaging features of adult Hirschsprung disease (HD) and adult hypoganglionosis (HG) and to compare these features with histopathologic findings.

MATERIALS AND METHODS

This study was institutional review board approved, and the requirement for informed consent was waived. The imaging, medical, and histopathologic data of 10 patients (seven women, three men; mean age, 38 years) with histopathologically proved adult HD and/or adult HG were reviewed. Two radiologists reviewed 10 transverse computed tomographic (CT) scans and five double-contrast barium enema radiographs in consensus for the presence or absence and the location of the transition zone. The transverse diameter ratio of the most dilated colonic segment proximal to the transition zone to the narrowed colonic segment distal to the transition zone (ie, transition zone ratio), and the longitudinal length of the transition zone were also determined. The CT findings of HD and HG were compared by using the Mann-Whitney U test.

RESULTS

All patients with lifelong or chronic constipation had a transition zone in the upper part of the rectum or rectosigmoid junction (n = 5) or in the descending colon (n = 5) on the CT scans and the double-contrast barium enema radiographs. The transition zone ratio was significantly different between the patients with HD (median ratio, 4.0) and the patients with HG (median ratio, 2.0) (P = .016). However, there was no significant difference in the longitudinal length of the transition zone between the two patient groups (median ratios, 4.4 cm for HD group and 6.0 cm for HG group; P = .190).

CONCLUSION

A markedly dilated proximal colonic segment with a transition zone and a narrowed distal colonic segment on CT and double-contrast barium enema images in conjunction with chronic refractory constipation in an adult should suggest the diagnosis of adult HD or adult HG. The detection of a much higher transition zone ratio may help to establish the diagnosis of HD.