Rofo 2009; 181 - VO410_1
DOI: 10.1055/s-0029-1221632

Towards a software based PET/MR: A new approach for highly accurate registration of PET and MRI scull base to inguinal imaging

S Thees 1, K Kendziorra 2, D Marwede 2, H Kirsten 1, D Fritsch 1, M Moche 1, O Sabri 2, T Kahn 1
  • 1Universitätsklinikum Leipzig AöR, Klinik und Poliklinik für Diagnostische und Interventionelle Radiologie, Leipzig
  • 2Universitätsklinikum Leipzig AöR, Klinik und Poliklinik für Nuklearmedizin, Leipzig

Ziele: To design and to evaluate a framework allowing for software based, highly accurate registration of PET and MRI nearly whole-body imaging (from scull base to inguinal). Methode: A new approach to sequentially rigid and non-rigid registration of PET and MRI nearly whole-body imaging was applied: To determine the respective transformations Trigid and Tnon-rigid, first the CT-part of the PET/CT was registered at the MRI. Second the corresponding registration of PET and MRI was achieved by application of (Tnon-regid * Tregid) at the PET-part of the PET/CT.

To avoid unnecessary miss-registration in the raw scan-data patients underwent nearly whole-body MRI and subsequent PET/CT at the same day. Furthermore positioning of the patients at the PET/CT and MRI scanner was equalized using adapted positioning devices for the hand-over-the-head-supine position in both scanners.

Accuracy of registration was assessed as well by the maximum registration error at specific reference points as by a comparison of the reliability the underling anatomical structure of a tracer-accumulation could be determined at the PET/MR in comparison to the PET/CT. Ergebnis: In all of the Patients highly accurate registration between PET and MRI could be achieved. In most of the cases the maximum registration error was below 1cm. Furthermore determination of the underling anatomical structure of tracer-accumulation in both modalities (PET/MR and PET/CT) was highly concordant. Schlussfolgerung: The demonstrated framework, comprising a new approach to rigid and non-rigid PET/MRI registration as well as an equalized patient position at the MRI and PET/CT preformed on the same day, enables for highly accurate registration of PET and MRI nearly whole-body imaging.

In particular the software based PET/MR was proven to allow for a reliable determination of the underling anatomical structure a tracer-accumulation belongs to. Thus we regard the presented solution of a software based PET/MR ready for further clinical evaluation.

Korrespondierender Autor: Thees S

Universitätsklinikum Leipzig AöR, Klinik und Poliklinik für Diagnostische und Interventionelle Radiologie, Liebigstraße 20, 04103 Leipzig

E-Mail: sebastian.thees@medizin.uni-leipzig.de

MRT - PET - registration - PET/MR - PET/MRT