Skeleton Graph Matching vs. Maximum Weight Cliques aorta registration techniques.

Vascular diseases are one of the most challenging health problems in developed countries. Past as well as ongoing research activities often focus on efficient, robust and fast aorta segmentation, and registration techniques. According to this needs our study targets an abdominal aorta registration method. The investigated algorithms make it possible to efficiently segment and register abdominal aorta in pre- and post-operative Computed Tomography (CT) data. In more detail, a registration technique using the Path Similarity Skeleton Graph Matching (PSSGM), as well as Maximum Weight Cliques (MWCs) are employed to realise the matching based on Computed Tomography data. The presented approaches make it possible to match characteristic voxels belonging to the aorta from different Computed Tomography (CT) series. It is particularly useful in the assessment of the abdominal aortic aneurysm treatment by visualising the correspondence between the pre- and post-operative CT data. The registration results have been tested on the database of 18 contrast-enhanced CT series, where the cross-registration analysis has been performed producing 153 matching examples. All the registration results achieved with our system have been verified by an expert. The carried out analysis has highlighted the advantage of the MWCs technique over the PSSGM method. The verification phase proves the efficiency of the MWCs approach and encourages to further develop this methods.

Skeleton-based abdominal aorta registration technique.

Vascular diseases are the most challenging health problems in developed countries. The vascular segmentation as well as registration techniques are the topics of past and ongoing research activities. In this work we target an abdominal aorta registration technique. The developed methodology is useful in the assessment of abdominal aortic aneurysm treatment by visualizing the correspondence between pre- and postoperative Computed Tomography (CT) data. The presented approach makes it possible to match all voxels belonging to the aorta from different CT series. It is based on aorta lumen segmentation and graph matching method. To segment the lumen area a hybrid level-set active contour approach is used. The matching step is performed based on a path similarity skeleton graph matching procedure. The registration results have been tested on the database of 8 patients, for which two different contrast-enhanced CT series were acquired. All registration results achieved with our system and verified by an expert prove the efficiency of the approach and encourage to further develop this method.

[The palliative treatment of primary hepatocellular carcinoma by chemoembolization]. / Palliative Behandlung des primären Leberzellkarzinoms mit Chemoembolisation.

16 patients (12 men, 4 women; mean age 62.8 +/- 9.8 years) with inoperable advanced hepatocellular carcinoma were treated palliatively by chemoembolization. 50 mg/m2 epirubicin, 30 mg/m2 cisplatin, 8 ml fatty acid ethyl ester of iodinated papaver oil and 10 ml nonionic contrast medium were injected under fluoroscopy into the proper hepatic artery. Partial remission was achieved in 10 patients after a median of 4 months. In 4 patients there was no change in the morphological and biochemical findings, in two others the tumour progressed, i.e. an overall response rate of 62.5%. The median survival time was 9 months. There were no serious complications ascribable to the treatment. Chemoembolization is a palliative treatment with few side effects which can also be effective in prolonging survival time in advanced hepatocellular carcinoma.

[The results of the chemoembolization of advanced hepatocellular carcinomas. The effect on the survival times, morphological findings and tumor markers]. / Ergebnisse der Chemoembolisation fortgeschrittener Leberzellkarzinome. Einfluss auf Uberlebenszeiten, morphologische Befunde und Tumormarker.

Chemoembolization is a well-recognized therapeutic procedure in the treatment of stage I and stage II hepatocellular carcinoma (HCC). Until now it is rarely used in the treatment of stage III HCC. In a prospective study we analysed the efficacy and the side effects of chemoembolization in 16 patients with stage III HCC. Chemoembolization was performed with an emulsion of lipiodol, 4-epirubicin and cisplatinum. All patients tolerated the treatment without remarkable complications. With 9 months the median survival rate was considerable higher than the survival rate of untreated patients and of patients treated with systemic chemotherapy or with local perfusion.

[Long-term experience with a PACS subsystem]. / Langzeiterfahrungen mit einem PACS-Subsystem.

Our experiences with a PACS-Subsystem have shown, that it would be more usefull and less expensive, first to install digital archiving systems in single areas. After a certain time of errorfree working the subsstems should be integrated into a superior information system. Fast data networks and userfriendly viewing stations are a basic requirement. Common standards of archiving, independent of the manufacturer, should be considered.

[Renin-angiotensin system under extracorporeal circulation during heart valve surgery]. / Das Renin-Angiotensin-System unter extrakorporaler Zirkulation während Herzklappenoperationen.

Angiotensin I (A I), angiotensin II (A II) and the activity of angiotensin-converting enzyme (ACE) were measured in 15 patients undergoing cardiopulmonary bypass for mitral or aortic valve replacement. During cardiopulmonary bypass A I, A II, A I/II ratio and arteriovenous A II--difference decreased markedly, whereas the activity of ACE fell only during a small 15 min period after start of extracorporeal circulation. Possible reasons for these effects are discussed.