Intestinal Dynamic Color Doppler Sonographic Tissue Perfusion Measurement

The evaluation of intestinal diseases encompasses morphological as well as functional aspects. The proper function of any organ depends on a sufficient blood supply to meet its actual metabolic needs. Blood flow though is a measure of physiological and pathophysiological tasks which are accomplished by the respective organ. Thus, many of these tasks can be described by measuring the amount of blood passing through tissues. Inflammation is an excellent example of such a response to a stimulus which increases tissue perfusion. The measurement of perfusion intensity would be helpful to monitor inflammatory processes. In contrast to the obvious advantages of such an approach only very limited methods exist to quantify perfusion of the bowel today. Contrast media in MRI, CT and angiography can give a vague impression of the quality of bowel perfusion but are not usable to quantify perfusion. Doppler ultrasound is used to record changes of blood flow velocity in the main intestinal arteries to calculate the so called Resistance Index (RI) and the related Pulsatility Index (PI). Both cannot describe the amount of intestinal blood since they lack the information of the width of the intestinal vascular network. Besides the actual flow velocity inside each vessel the vessel width is the other necessary constituent to calculate flow intensity or volume inside a tissue. We developed a novel method to overcome these limitations the Dynamic Color Doppler Sonographic Tissue Perfusion Measurement (DTPM). The following chapter describes the principle of DTPM and its use in gastroenterology. DTPM was developed to meet so far unsatisfied daily needs in clinical practice, to quantify tissue perfusion in order to answer pressing clinical questions: is the tissue viable, is it damaged and to which extent, is there an inflammatory hyperperfusion, is the blood supply to an organ sufficient to fulfill its tasks properly.