Purpose: Assessment of the diagnostic efficacy of triphasic spiral-CT scanning (TPS-CT) for liver disease evaluation. CT arteriography (CTA) and CT arterioportography (CTAP) were used as reference, methods which together have the highest sensitivity for detecting tumours and the perfusion conditions of the liver.Material and methods: 50 TPS-CT and CTA/CTPA were performed in 49 patients. After an initial examination without enhancement the first scan was initiated 15-25 s after the peripheral bolus injection of contrast medium, the second after an interscan delay of 20-25 s. By this means the liver was imaged in different phases of perfusion. In the course of the CTA/CTPA-exam the imaging was carried out after selective, intraarterial application of contrast agent.Results: The differentiation of the perfusion phases succeeded in 90% of the patients. When compared with standard CT, which images only the portal venous phase, the new technique, which additionally shows the arterial perfusion, accomplished an increase in sensitivity for hypervascular lesions (51 % vs. 60 %). Yet in comparison with CTA/CTPA fewer lesions could be detected (87 vs. 138). Furthermore, by documenting the contrast agent kinetics, characterisation of the lesion was also facilitated.Conclusion: DPS-CT is a valuable additional tool for imaging the liver, even if the information yield is less when compared to CTA/CTPA.

Acute exacerbations of chronic inflammatory bowel disease (ulcerative colitis and Crohn's disease) are characterised by an increase in immunoglobulin G (IgG) positive cells in the mucosa, whereas uninflamed mucosa of inflammatory bowel disease patients displays only moderately increased or normal numbers of these cells. Previous data suggest that acute exacerbations of ulcerative colitis and Crohn's disease can be distinguished by different IgG subclass expression of mucosal immunocytes and a different IgG subclass production pattern of lamina propria lymphocytes. A procedure to obtain enough intestinal mononuclear cells from biopsy specimens to measure in vitro IgG and IgG1 production in control subjects and various patient groups has been established. IgG2 could be measured in Crohn's disease and ulcerative colitis only, as the concentrations in control subjects were below the sensitivity of the ELISA method. We found that IgG and IgG1 production correlated with the degree of local inflammation in both diseases, even in slightly inflamed mucosa, compared with control subjects. The proportion of IgG1 subclass was significantly increased in severely inflamed mucosa of both ulcerative colitis and Crohn's disease patients. A major difference between Crohn's disease and ulcerative colitis mucosa is apparent in mild or no inflammation. In Crohn's disease mucosa in remission, the IgG1/IgG ratio is comparable with that in controls, yet ulcerative colitis mucosa still displays significantly increased proportions of IgG1. In addition, the IgG2/IgG ratio is 0.12 in ulcerative colitis and 0.19 in Crohn's disease patients. The results show the dependence of local IgG and IgG1 production on the degree of inflammation and that an increase in subclass IgG1 in ulcerative colitis is present at all stages, including remission. These findings support the hypothesis that different immunoregulatory mechanisms are involved in Crohn's disease and ulcerative colitis. Environmental stimuli or genetic background may be responsible for the observed differences.

Die Ätiologie und die Pathogenese der Colitis ulcerosa (CU) und des M. Crohn (MC) sind bisher nicht geklärt, jedoch lassen verschiedene klinische und experimentelle Befunde auf eine Beteiligung des Immunsystems schließen. Es ist seit vielen Jahren bekannt, daß sich bei MC und CU in der Lamina propria der entzündeten Mukosa eine Zunahme der mononukleären Zellen findet. Eine Teilpopulation dieser Zellen enthält zytoplasmatisches oder membrangebundenes Immunglobulin (Übersicht bei [2]). In normaler Darmmukosa überwiegen IgA-positive Zellen. Da das von diesen Zellen produzierte IgA keine oder nur schwache inflammatorische Wirkungen hat, kommt es in der Regel zu einer Immunexklusion ohne Komplement-oder Zellaktivierung. Im Gegensatz dazu wird durch Antikörper der IgG-Klasse eine entzündliche Reaktion unterstützt. Insbesondere die IgG-Subklasse-1 zeichnet sich durch eine ausgeprägte Fähigkeit zur Komplementaktivierung aus, so daß Antikörper dieses Isotyps bei gleicher Antigenspezifität wie IgA möglicherweise eine Entzündung mit Epitheldestruktion auslösen.