LAUSR

W e would like to thank Dr Xu for the interest in our article “Spatial Distribution of Pancreatic Stones in Chronic Pancreatitis.” First, our effort to optimize this mathematical model of spatial distribution of pancreatic stones has never stopped. The current mathematical model is really built on the hypothesis that the pancreas is in a standard spherical shape and stones are randomly distributed in the ball. In fact, the pancreas is long, narrow, and asymmetrical. Chronic pancreatitis is a progressive disease with irreversible destruction of the pancreatic parenchyma and ductal structures, characterized by atrophy and fibrosis of pancreas; thus, the shape is more diverse and irregular. We are in progress of collecting and processing large amounts of pancreatic imaging data to optimize the model based on the fact that the pancreas is composed of pancreas head, body, and tail. Ideally, we could develop an average shape of pancreas as the standard mathematical model to analyze the degree of pancreatic parenchymal atrophy and spatial distribution of pancreatic stones. Second, the basic calculation method for 3-dimensional (3D) is similar to 2-dimensional (2D), but the amount of data needed for 3D reconstruction calculation would markedly increase, and the computing equipment also needs to be innovated and optimized. Coronal reformatted images are the most commonmethod of computed tomography (CT) reconstruction to evaluate pancreatic anatomy. Thus, we initially established a standard to describe the spatial distribution of pancreatic stones through 2D coronal projection instead of 3D images, and the 2D model is simple and practicable currently, which could meet the clinical demand. We will continue collecting relevant data to further analyze the spatial distribution of pancreatic stones through 3D reconstruction. Third, it is a brilliant idea to depict the main pancreatic duct and branch ducts in