Developing patient-specific anatomic models for validation of cardiac ablation guidance procedures

Image-guided cardiac ablation has the potential to decrease procedure times and improve clinical outcome for patients with cardiac arrhythmias. There are several proposed methods for integrating patient-specific anatomy into the cardiac ablation procedure; however, these methods require thorough validation. One of the primary challenges in validation is determining ground truth as a standard for comparison. Some validation protocols have been developed for animals models and even in patients; however, these methods can be costly to implement and may increase the risk to patients. We have developed an approach to building realistic patient-specific anatomic models at a low-cost in order to validate the guidance procedure without introducing additional risk to the patients. Using a pre-procedural cardiac computed tomography scan, the blood pool of the left and right atria of a patient are segmented semi-manually. In addition, several anatomical landmarks are identified in the image data. The segmented atria and landmarks are converted into a polygonalized model which is used to build a thin-walled patient-specific blood pool model in a stereo-lithography system. Thumbscrews are inserted into the model at the landmarks. The entire model is embedded in a platinum silicone material which has been shown to have tissue-mimicking properties relative to ultrasound. Once the pliable mold has set, the blood pool model is extracted by dissolving the rigid material. The resulting physical model correctly mimics a specific patient anatomy with embedded fiducals which can be used for validation experiments. The patient-specific anatomic model approach may also be used for pre-surgical practice and training of new interventionalists.