Computertomographie-gestützte Charakterisierung arterieller Verschlüsse der unteren Extremität zur Prognosebeurteilung hinsichtlich ihres Ansprechens auf eine lokale Lysetherapie

This thesis examines retrospectively if there is a possibility to evaluate the success of catheter directed thrombolysis in acute arterial limb ischemia of the lower extremity predictively on the basis density, length and volume measured in computed tomography angiography images. Therefore data of 31 of 4.826 patiens who have been treated in the clinic for diagnostical and interventional radiology of the university hospital of Marburg over a time period of six years were analysed. On the basis of result of catheter directed thrombolysis therapy (CDT) all patients were attributed to either the group named “succsess of CDT“ („Lyse Erfolg“) or the group named “failure of CDT“ („Lyse Misserfolg“). Subsequently these two groups were compared. It turned out that the occlusion sites in the "CDT failure" group differed significantly in terms of attenuation coefficient and length. An algorithm was created, which allows a precise selection of patients who can be recommended for CDT. In the first step of the diagnostic algorithm, the length of the occlusion is measured. Using a cutoff value of 360 mm, the patient is assigned to one of two groups A or B. If the measured length is less than 360 mm, the patient is assigned to group A and if the length is 360 mm or more to group B. In the second step, the attenuation coefficients were used as the deciding parameter. In group A, the cutoff value was 59 HU, so all those with coefficients <59 HU were assigned to group A1 and all ≥59 HU to group A2. Similarly, group B is divided into two subgroups, B1 and B2, with a cutoff value of 48 HU. Patients are assigned to group B1 if the coefficient is <48 HU and to group B2 if it is ≥48 HU. CDT is recommended for the groups A1 and B1. This algorithm extandes the value of the diagnostical process and is part of a non-invasive, fast, and cost-effective imaging so that the integration into everyday clinical work is possible in an easy way. By selecting patients more precisely for CDT, the success of the therapy can be maximized and the risks can be minimized. In summary, these data show that a pre-therapeutic assessment of the success of CDT based on measurements from CTA datasets is possible and can help to clarify and simplify the indication fort this type of therapy.