4D analysis of the heart
Alfredo Lopez presented at the SPIE, the conference for medical imaging, the paper „3D inter-subject cardiac registration using 4D information“.
The authors of that paper are: Alfredo López, Software Competence Center Hagenberg (Austria); Karl Fritscher, Univ. für Gesundheitswissenschaften, Medizinische Informatik und Technik (Austria); Thomas Trieb, Innsbruck Medical Univ. (Austria); Rainer Schubert M.D., Univ. für Gesundheitswissenschaften, Medizinische Informatik und Technik (Austria); Julian Mattes, Software Competence Center Hagenberg (Austria)“.
New diagnostic methods for heart diseases
This research project was executed within the framework of an EU funded program called IPECA. In the context of that project new diagnostic methods for heart diseases will be developed. The research study is mainly focused on myocarditis, a disease pattern of the myocardial muscle. The basis for the scientific work are cardiac SPECT and MR images showing the cardiac cycle. An average cardiac cycle lasts about 0,5 and 0,7 seconds. For obtaining reliable data, every 50 millisecond a 3D picture of the heart is made.
At the moment, doctors are missing a tool, which supports them in the interpretation of the SPECT and MR images. A computer based tool would help them to asses the constitution of the patient. The aim of this research project is to quantify the differences in the motion of the heart and to present those differences in a suitable visual illustration.
Scientific approach: 4D-analysis and 4D-registration
Images of the hearts anatomic structure of two different groups (patients with heart diseases and healthy test persons) will be compared and analyzed with statistical methods. This procedure should indicate how the motion of a healthy structure differs from the motion of the same kind of structure but in a pathological state.
When dealing with sequences of 3D images a 4D registration of the image sequences is essential for the comparison of motion or shape at selected points in time. 4D registration means to register no only 3D images of a time sequence but to register two different time sequences as a whole, called a “spatio-temporal alignment”. It implies a temporal alignment of the sequences as well as a spatial alignment. 4D registration has also been used to compare sequences acquired with different modalities, for instance gated cardiac SPECT images with MR images.
The approach proposed works with “bridging point” registration. It allows using additional information provided by the user for a one single or two selected pair of points in time. The selected pairs of points in time are called bridging points (in time). Here the researchers calculated first a temporal association between the images of the two sequences. Beside that, a linear temporal alignment of the two sequences using temporal nearest neighbor interpolation was used.
With that approach we gain up to 33% in registration accuracy, mentions Alfredo Lopez and Julian Mattes, head of Biomedical Data Analysis, adds: “we intend to test our technology on a larger selection of patients, additionally we plan to apply our technique to investigate the evolution of the cardiac motion of patients suffering from myocarditis.
EU research program
The project was funded by the EU-Program ALFA (Latina – Formación Académica). European partner universities within the project are the university Joseph Fourier Grenoble (UFJ), the „Private Universität für Gesundheitswissenschaften, Medizinische Informatik und Technik (UMIT)“, „Die Freie Universität Brüssel“ and the university of Rennes. In South America, the university of Santiago de Chile and other universities from Venezuela and Mexico are involved. Because of that research program Alfredo Lopez, who studied at the university of Santiago de Chile and holds a degree in mathematics for industrial use, came to Austria. At the Software Competence Center Hagenberg, he will finish his Ph.D. thesis “comparative analysis of the motion of the heart”, which is supervised and supported by Julian Mattes.