More people die from this disease in Germany than from traffic accidents: around 10,000 deaths per year can be traced back to a ruptured aortic aneurysm. An aneurysm is a bulging of a blood vessel caused by fatigue of the vessel wall. If the dilated area tears, the consequences can be fatal: If a large artery such as the aorta is affected, the patient can bleed to death within a very short time.
Aneurysms of the abdominal aorta are not at all rare. In Western Europe and the USA, three percent of men and one percent of women between the ages of 65 and 70 are affected, as Armin Huß explains. The disease often remains symptom-free – the challenge is to even notice the aneurysm and then decide whether the risk of rupture is so great that surgery is necessary.
Huß has set himself the goal of improving the diagnosis of aneurysms, even though he is not a doctor, but a professor of technical mechanics. He and his colleagues at the Frankfurt University of Applied Sciences have been working for years on making engineering findings usable for medicine. To do this, they assess overstretched blood vessels in the body using similar criteria to those used by a materials tester who examines a strained metal pipe.
4D ultrasound shows deformations of the aortic wall
To assess how dangerous an aneurysm is, angiologists typically measure its size and observe whether it changes over time. An engineer who wants to assess the breaking strength of a pipe is also interested in the stresses in the metal in order to recognize when things become dangerous, says Huß. He and his colleagues use 4D ultrasound to show the deformations of an aortic wall. This technique, which allows an organ and its movements to be mapped three-dimensionally over time, has been used in medicine for a long time.
Red means danger: deformation of an aneurysm in 4D ultrasoundFAST
Huß’ colleagues Christopher Blase and Andreas Wittek have developed software that enables deformation measurements of the abdominal aorta in living people. The image of the organ is divided into segments and a relative deformation is given for each section. From the materials researcher’s point of view, it becomes particularly dangerous when severely deformed areas border sections that hardly warp: the probability of a crack is particularly high there, says Huß.
The data provided by 4D ultrasound, along with other measurements, could help doctors better assess a patient’s individual risk. Unnecessary interventions could then possibly be avoided. According to the professor, the necessary ultrasound devices are available in the clinics and practices. They would only need to be equipped with suitable commercial software based on the program developed at Frankfurt University.
To test their method, the researchers recently conducted a study in collaboration with the University Hospitals of Frankfurt and Heidelberg. 22 patients with abdominal aortic aneurysms were examined. The doctors compared the results of a computed tomographic angiography with those of a 4D ultrasound. According to Manuel Schönborn, doctoral student and co-author of the study, both methods can complement each other at the current stage of development.
Aneurysms can occur not only in the aorta, but also in cerebral vessels and can be just as dangerous there. Huss does not rule out that the findings of his working group could also help in assessing such vulnerabilities. Little can be done in the brain with ultrasound, but deformation measurements are also possible with computer tomography – although the high radiation exposure must be taken into account.