Investigation of the XCAT phantom as a validation tool in cardiac MRI tracking algorithms

Nicholas Lowther*, Svenja Ipsen, Steven Marsh, Oliver Blanck, Paul Keall

*Corresponding author for this work
1 Citation (Scopus)


Purpose: To describe our magnetic resonance imaging (MRI) simulated implementation of the 4D digital extended cardio torso (XCAT) phantom to validate our previously developed cardiac tracking techniques. Real-time tracking will play an important role in the non-invasive treatment of atrial fibrillation with MRI-guided radiosurgery. In addition, to show how quantifiable measures of tracking accuracy and patient-specific physiology could influence MRI tracking algorithm design. Methods: Twenty virtual patients were subjected to simulated MRI scans that closely model the proposed real-world scenario to allow verification of the tracking technique's algorithm. The generated phantoms provide ground-truth motions which were compared to the target motions output from our tracking algorithm. The patient-specific tracking error, ep, was the 3D difference (vector length) between the ground-truth and algorithm trajectories. The tracking errors of two combinations of new tracking algorithm functions that were anticipated to improve tracking accuracy were studied. Additionally, the correlation of key physiological parameters with tracking accuracy was investigated. Results: Our original cardiac tracking algorithm resulted in a mean tracking error of 3.7 ± 0.6 mm over all virtual patients. The two combinations of tracking functions demonstrated comparable mean tracking errors however indicating that the optimal tracking algorithm may be patient-specific. Conclusions: Current and future MRI tracking strategies are likely to benefit from this virtual validation method since no time-resolved 4D ground-truth signal can currently be derived from purely image-based studies.

Original languageEnglish
JournalPhysica Medica
Pages (from-to)198-204
Number of pages7
Publication statusPublished - 01.01.2018


Dive into the research topics of 'Investigation of the XCAT phantom as a validation tool in cardiac MRI tracking algorithms'. Together they form a unique fingerprint.

Cite this