A introduction to metacalibration methods and their application. This includes a new proof of the double bubble conjecture, new results in the area of equitent problems (isoperimetric problems with boundary), and comments on a mapping conjecture.

No

Infantile hypertrophic pyloric stenosis (IHPS) is a disorder characterized by hypertrophy of the pylorus causing obstruction of the gastric outlet. IHPS occurs in 1 to 3.5 per 1000 live births and normally develops between weeks 3 to 5 of age. Patients commonly present forceful, projectile, nonbilious vomiting. The diagnosis is confirmed with ultrasound in which pyloric muscle thickness (PMT) and pyloric canal length (PCL) are measured as less than or equal to 3.0 mm and 14.5 mm, respectively. Definitive treatment is surgicalpyloromyotomy. Similarly, duodenal atresia can cause projectile, nonbilious vomiting. However, it typically presents within the first 24 to 38 hours of birth. If not diagnosed antenatally, then the classic “double bubble sign” on abdominal x-ray or upper GI series is pathognomonic. In this case study, we discuss a case in which diagnostic imaging leads to the misdiagnosis of a patient presenting with projectile vomiting. Initial presentation, differential diagnosis, and hospital workup will be discussed. We present this case study to raise awareness of the possible misdiagnosis of a common childhood illness due to aberrant radiographic presentation.