Abstract 14649: Assessment of Acute Cryo and RF Ablation Lesions by Non-contrast and Contrast Enhanced MRI Techniques: Similarities and Differences
Introduction: MRI is used to assess acute RF lesions. Cryo-ablation is being increasingly used for EP procedures. No previous studies were performed to assess acute cardiac cryo ablations by MRI. In this study, we have compared visibility of acute cryo and RF lesions using non-contrast and contrast enhanced MRI techniques.
Methods: Cryo and RF ablations of left and right ventricles were performed in 4 canines. Cryo lesions were created using cryo-catheter (Freezor MAX, Medtronic) with freeze times of 2 and 4 minutes. RF lesions were created by ThermoCool catheter (Biosense Webster) at 30 Watts for 30 seconds. Animals were then moved to a 3 Tesla MRI scanner (Verio, Siemens). Imaging included T1-weighted (T1w) and T2w scans, followed by injection of gadolinium-based contrast (0.15 mmol/kg, Multihance (Bracco)) and post-contrast T1w and late gadolinium enhancement (LGE) scans.
Results: Representative T1w, T2w, and post-contrast T1w and LGE images of acute cryo and RF lesions are shown in Fig. 1. All RF lesions were readily detectable on non-contrast T1w images. No cryo lesions were found on non-contrast T1w images (Fig. 1a). Degree and extent of post-ablation edema assessed by T2w images was noticeably different for cryo and RF ablations (Fig. 1b). Edema was very apparent and extended widely beyond lesion core for RF ablations while it was less obvious and mainly restricted to lesion core for cryo ablations. Visibility of cryo and RF lesions was similar in post-contrast T1w and LGE images (Fig. 1c, 1d).
Conclusions: Post-contrast T1w and LGE MRI demonstrated that acute cryo and RF lesions have similar contrast kinetics: significantly slower wash-in and wash-out than that of healthy tissues. Non-contrast T1w MRI is useful for detection of acute RF ablations. However, this technique is not applicable for cryo ablations. Edema caused by cryo and RF ablations can be visualized by T2w MRI. RF ablations result in more apparent and extended edema than edema caused by cryo ablations.
Author Disclosures: E. Kholmovski: Research Grant; Significant; Marrek Inc. R. Ranjan: Honoraria; Modest; Medtronic. Consultant/Advisory Board; Modest; Boston Scientific. J. Silvernagel: None. J. Blauer: None. N. Marrouche: Research Grant; Significant; eCardio, Atricure. Other Research Support; Significant; Siemens. Honoraria; Modest; Biotronik, Boston Scientific, Boehringer Ingelheim. Ownership Interest; Significant; Marreck, UMS, Cardiac Designs, Arapeen Medical, Sentiomed. Consultant/Advisory Board; Significant; Aricure, eCardio.
- © 2014 by American Heart Association, Inc.