Calculating windowing width and level from Image pixel data can be done via accessing the raw pixel data and applying your own algorithm or via the DicomObjects method SetDefaultWindows of the DicomImage object.

The Width COM/.NET and Level COM/.NET properties of an image are unusual, in that they are both stored as a part of the image, and are also transient DicomImage properties, regularly adjusted by users. This page explains the relationship between the persistent and transient values.

For plain radiographs (conventional x-rays), the size recorded on the film is always larger than the size of the object being imaged, due to an effect called geometric magnification.

This article explains how to get the fastest performance for cine images such as cardiac angiograms