Video Dimension Analyzer

Automatically Measures Lumen Diameter & Wall Thickness

Model V94

Continuously measures the lumen diameter and wall thickness of isolated, cannulated vessels of 50 - 350 µm diameter that may be imaged through a television camera attached to a microscope. For larger vessels, or those with thick walls, only the outside diameter can be measured. These measurements are displayed on digital panel meters, and analog output signals acquired for recording. Changes in dimensions arising from vessel constriction or dilation are automatically followed with rapid (<20 ms) time resolution.

The principle of the instrument is based on sensing optical density changes of the vessel image at a chosen scan line seen on the TV monitor. Rotation of the camera allows the scan line to perpendicularly intersect the long axis of the vessel. Initially, the width of two windows in the scan line is set to bracket the vessel wall. Trigger controls are then adjusted to sense the wall that is more optically dense than the lumen and the image outside the vessel. A switch also allows triggering at the transition from a dark background to an optically bright one. This feature can be useful for fluorescent tissue images and certain other situations. Once these settings are made they do not require further adjustment during the course of the experiment.

V94 Specifications