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Patient body motion correction for dynamic cardiac PET ‐ CT by attenuation‐emission alignment according to projection consistency conditions
Author(s) -
Hunter Chad R. R. N.,
Klein Ran,
Alessio Adam M.,
deKemp Robert A.
Publication year - 2019
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1002/mp.13419
Subject(s) - imaging phantom , correction for attenuation , cardiac pet , nuclear medicine , positron emission tomography , projection (relational algebra) , iterative reconstruction , partial volume , computer science , attenuation , computer vision , cardiac imaging , data consistency , torso , artificial intelligence , algorithm , physics , medicine , radiology , optics , anatomy , operating system
Patient body motion is known to cause large deviations in the determination of myocardial blood flow ( MBF ) with errors exceeding 300%. Accurate correction for patient whole‐body motion is still a largely unsolved problem in cardiac positron emission tomography (PET) imaging. Objective This study evaluated the efficacy of using Natterer's formulation of the Helgason–Ludwig consistency conditions on the two‐dimensional Radon transform to align computed tomography to PET projection data in multiple time frames of a dynamic sequence for the purpose of frame‐by‐frame correction of rigid whole‐body motion. Methods The correction algorithm was evaluated with digital NCAT phantoms using realistic noise added by the analytical simulator. Count rates used in the simulation were derived from clinical patient data. In addition, a proof of concept test using measured data with a cardiac torso phantom was conducted. Results Motion correction resulted in significant improvement in the accuracy of MBF estimates, especially for high count‐rate acquisitions. Maximum errors for 2 cm of motion dropped from 325% to 25% and from 250% to 25% using global and regional partial‐volume correction, respectively. Median MBF errors dropped from 33% to 4.5% and 27% to 3.8%, respectively. Importantly, the correction algorithm performed equally well to compensate for body motion in both early and late time frames. Conclusion Cardiac PET ‐CT data used for attenuation correction ( CTAC ) alignment using projection consistency conditions was effective for reducing errors in MBF measurements due to simulated patient motion, and can be integrated into the image reconstruction workflow.