A. Martinez-Möller, B. Jensen, N. Navab, M. Schwaiger, S. Nekolla Automatic cardiac PET-SPECT and SPECT-SPECT registration Journal of Nuclear Medicine 2008, 49 (suppl. 1), p31. Proceedings of Annual Meeting of Society of Nuclear Medicine (SNM 2008), New Orleans, LA, USA, June 2008 (bib)
	Objectives Combination of examinations acquired in rest and stress or the assessment of perfusion and metabolism is a unique capability of nuclear imaging. However, most protocols require that the patient leaves the scanner between examinations or even use different modalities. The alignment of these studies is mostly done manually which introduces a potential bias. Thus we aimed at the development and initial validation of an automated approach suitable for both SPECT and PET. Methods: Using the ITK toolkit, an automatic rigid image registration using Mattes’ mutual information was implemented and applied in 2 consecutive sets of patients: 12 patients undergoing a rest/stress Tc99m-SPECT and 12 patients undergoing a rest Tc99m-SPECT and an FDG PET for viability assessment. Manual reference registration was performed by an experienced observer. The deviation of the automatic alignment was then compared to the reference. In addition, a second observer blinded to the previous results assessed the visual quality of the algorithm. Results: The average translation between the reference and the automatic approach in x,y,z was 2.3mm, 3.3mm and 4.9mm for PET-SPECT and 3.1mm, 1.1mm, 1.8mm for SPECT-SPECT. The difference in the rotations was minimal (<1°). In the quality read, 2/12 PET-SPECT and 1/12 SPECT-SPECT registrations were found to need a manual correction (25mm, 19mm, 13mm translations).The average time needed for the automatic registration was 30s for PET-SPECT, 3s for SPECT-SPECT on standard computers. Manual registration required 2-3 min per case. Conclusions: Automatic registration of cardiac studies is successfully achieved for intra- and intermodal PET and SPECT imaging. This offers the potential of an additional improvement of the clinical workflow with respect to analysis time and reproducibility.</TD>
	This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each authors copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.