Three-dimensional simulation of lung nodules for paediatric multidetector array CT.

The purpose of this study was to develop and validate a technique for three-dimensional (3D) modelling of small lung nodules on paediatric multidetector array computed tomography (MDCT) images. Clinical images were selected from 21 patients (<18 years old) who underwent MDCT examinations. Sixteen of the patients had one or more real lung nodules with diameters between 2.5 and 6 mm. A mathematical simulation technique was developed to emulate the 3D characteristics of the real nodules. To validate this technique, MDCT images of 34 real nodules and 55 simulated nodules were randomised and rated independently by four experienced paediatric radiologists on a continuous scale of appearance between 0 (definitely not real) and 100 (definitely real). Receiver operating characteristic (ROC) analysis, t-test, and equivalence test were performed to assess the radiologists' ability to distinguish between simulated and real nodules. The two types of nodules were also compared in terms of measured shape and contrast profile irregularities. The areas under the ROC curves were 0.59, 0.60, 0.40, and 0.63 for the four observers. Mean score differences between simulated and real nodules were -8, -11, 13, and -4 for the four observers with p-values of 0.17, 0.06, 0.17, and 0.26, respectively. The simulated and real nodules were perceptually equivalent and had comparable shape and contrast profile irregularities. In conclusion, mathematical simulation is a feasible technique for creating realistic small lung nodules on paediatric MDCT images.

Intestinal malrotation in neonates with nonbilious emesis.

Intestinal malrotation is a relatively uncommon condition with diverse outcomes. Familiarity with variations in the presentation of malrotation is imperative as early diagnosis and prompt subsequent surgical intervention are essential to optimizing outcome. The most frequent clinical sign in the neonate is bile-stained emesis. We report three cases of unsuspected malrotation that were diagnosed in neonates with a history of nonbilious emesis who were assessed for presumed gastroesophageal reflux or aspiration. Gastroesophageal reflux is a common condition among newborns, and can be a subtle presentation of malrotation. Clinicians should consider malrotation as a possible cause of reflux, particularly in infants with unusually pathologic or persistent symptoms necessitating ongoing treatment for reflux.