Morphological evaluation for the narrowest section of the patent ductus arteriosus in infants by CT: a crucial point for device closure.

Background: The minimum diameter of the patent ductus arteriosus measured in the lateral angiographic view is usually used to determine the device size. Sometimes the device can be easily removed from the patent ductus arteriosus, even if it appears to be the optimum size.
Methods: From 2016 to 2021, 29 patients who underwent contrast-enhanced CT prior to patent ductus arteriosus closure included. Morphological evaluation of the narrowest part of the patent ductus arteriosus was performed on contrast-enhanced CT. We also examined whether there were differences in morphology depended on Krichenko classification, age, and the diameter of the narrowest portion of the patent ductus arteriosus.
Results: At the time of treatment, the median age was 4.8 (range, 1-52) months, and the median weight was 5.0 (2.5-12.7) kg. The median minimum vertical diameter of patent ductus arteriosus was 2.9 (1.6-6.6) mm. The narrowest patent ductus arteriosus part in the contrast CT imaging showed horizontal-to-vertical diameter ratios in the range of 1.0-1.7, with no case where the vertical diameter was larger than the horizontal diameter. The median horizontal-to-vertical diameter ratio by Krichenko type was: A, 1.22; C, 1.29; E, 1.62(p = 0.017). When classifying the patients into a group aged under six months (n = 21) and a group aged six months or older (n = 8), the respective median horizontal-to-vertical diameter ratio was 1.34 and 1.15 (p = 0.027). The vertical patent ductus arteriosus diameter was not correlated with the elliptical shape.
Conclusions: Most patent ductus arteriosus cases have a horizontally oriented elliptical shape in this study. This characteristic showed high reproducibility and is important information that angiography cannot evaluate.