technetium-tc-99m-mebrofenin and Intestinal-Diseases

A redundant collateral network between the intestinal arteries is present at all times. In case of ischaemia in the gastrointestinal tract, the collateral blood supply can develop further, thus accommodating the demand for oxygen even in the presence of significant stenosis or occlusion of the intestinal arteries without clinical symptoms of intestinal ischaemia. Symptoms of ischemia develop when the genuine and collateral blood supply no longer can accommodate the need for oxygen. Atherosclerosis is the most common cause of obliteration in the intestinal arteries. In chronic intestinal ischaemia (CII), the fasting splanchnic blood flow (SBF) is sufficient, but the postprandial increase in SBF is inadequate and abdominal pain will therefore develop in relation to food intake causing the patient to eat smaller meals at larger intervals with a resulting weight loss. Traditionally, the CII-diagnosis has exclusively been based upon morphology (angiography) of the intestinal arteries; however, substantial discrepancies between CII-symptoms and the presence of atherosclerosis/stenosis in the intestinal arteries have been described repeatedly in the literature impeding the diagnosis of CII. This PhD thesis explores a method to determine the total SBF and its potential use as a diagnostic tool in patients suspected to suffer from CII. The SBF can be measured using a continuous infusion of a tracer and catheterisation of a hepatic vein and an artery. By measuring the SBF before and after a standard meal it is possible to assess the ability or inability to enhance the SBF and thereby diagnosing CII. In Study I, measurement of SBF was tested against angiography in a group of patients suspected to suffer from CII due to pain and weight loss. A very good agreement between the postprandial increase in SBF and angiography was found. The method was validated against a well-established method independent of the hepatic extraction of tracer using pAH in a porcine model (study II). An excellent agreement was found between the two methods for the measurement of SBF. In the same set-up metabolism and recirculation in the intestines of the 99mTechnetium labelled tracer was rejected based on the consistency between the portal and arterial contents of tracer. Based on this study we concluded that an arterial blood sample can be used instead of a portal blood sample, making the method applicable to patients. In study III, 20 healthy volunteers and 29 patients with weight loss and

Topics: Angiography; Aniline Compounds; Animals; Anthropometry; Chronic Disease; Fasting; Glycine; Humans; Imino Acids; Intestinal Diseases; Ischemia; Organotechnetium Compounds; Oxygen Consumption; p-Aminohippuric Acid; Postprandial Period; Radiopharmaceuticals; Splanchnic Circulation; Swine