Purpose: To evaluate the use of contrast material-enhanced magnetic resonance (MR) imaging with conventional T1-weighted gradient-recalled echo (GRE) and inversion-recovery (IR)-prepared GRE methods to quantitatively measure the size of irreversible electroporation (IRE) ablation zones in the liver in a rat model.
Materials And Methods: All studies were approved by the institutional animal care and use committee and were performed in accordance with institutional guidelines. Seventeen adult male Sprague-Dawley rats were divided into four groups. Rats in groups 1-3 (n = 15 total) underwent IRE performed by using different IRE parameters after gadopentetate dimeglumine administration. Rats in group 4 (n = 2) underwent IRE ablation without prior gadopentetate dimeglumine injection to serve as control animals. MR imaging measurements (with conventional T1-weighted GRE and IR-prepared GRE methods) were performed 2 hours after IRE to predict the IRE ablation zones, which were correlated with pathology-confirmed necrosis areas 24 hours after IRE by using the Spearman correlation coefficient. Bland-Altman plots were also generated to investigate the agreement between MR imaging-measured ablation zones and reference standard histologic measurements of corresponding ablation zones.
Results: The necrotic areas measured on the pathology images were well correlated with the hyperintense regions measured on T1-weighted GRE images (r = 0.891, P < .001) and normal tissue-nulled IR images (r = 0.874, P < .001); pathology measurements were also well correlated with the smaller hyperintense regions measured on those IR images with inversion times specifically selected to null signal from the peripheral penumbra surrounding the ablation zone (r = 0.939, P < .001). Bland-Altman plots indicated that these penumbra-nulled IR images provided more accurate predictions of IRE ablation zones, with T1-weighted GRE measurements tending to overestimate ablation zone sizes.
Conclusion: Contrast-enhanced MR imaging permits accurate depiction of ablated tissue zones after IRE procedures. IR-prepared contrast-enhanced MR imaging can be used to quantitatively measure IRE ablation zones in the liver.
Supplemental Material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10100645/-/DC1.
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http://dx.doi.org/10.1148/radiol.10100645 | DOI Listing |
J Vasc Interv Radiol
January 2025
Department of Electrical and Computer Engineering, Kansas State University, Manhattan, KS 66506, USA; Department of Biomedical Engineering, The George Washington University, Washington, DC 20052, USA. Electronic address:
Purpose: To determine the technical feasibility of discriminating discontiguous from contiguous ablation zones between a pair of microwave ablation (MWA) applicators using broadband microwave transmission signal measurements in an in vivo porcine liver model.
Methods: Dual applicator 2.45GHz MWA was performed using one directional and one omnidirectional applicator, spaced 3cm apart, under imaging guidance.
Reg Anesth Pain Med
January 2025
Department of Anesthesiology & Critical Care Medicine, Memorial Sloan Kettering Cancer Center, New York, New York, USA
Background: Sacroiliac joint (SIJ) dysfunction accounts for the etiology of pain in 15%-30% of low back pain cases. Some patients with conservative treatment-refractory SIJ dysfunction undergo radiofrequency (RF) ablation of the SIJ for prolonged pain relief. This procedure involves placing up to 12 RF probes in what is an invasive, resource-intensive, and time-consuming process.
View Article and Find Full Text PDFHeart Rhythm
January 2025
Hacettepe University, Faculty of Medicine, Department of Cardiology, Ankara, Turkey.
Background: Atypical atrial tachycardia (AT) is a commonly encountered rhythm disorder especially in patients with underlying atrial scar. Peak frequency (PF) annotation of bipolar electrograms is a novel method, which mainly aims to discriminate near-field and far-field signals.
Objective: To evaluate the association between PF annotation of low-voltage zones (LVZ) and deceleration zones (DZ) during sinus / paced rhythm and their role to predict the critical isthmus (CI) and termination sites of atypical ATs.
PLoS One
January 2025
Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Objective: This study aimed to introduce and evaluate a novel software-based system, BioTrace, designed for real-time monitoring of thermal ablation tissue damage during image-guided radiofrequency ablation for hepatocellular carcinoma (HCC).
Methods: BioTrace utilizes a proprietary algorithm to analyze the temporo-spatial behavior of thermal gas bubble activity during ablation, as seen in conventional B-mode ultrasound imaging. Its predictive accuracy was assessed by comparing the ablation zones it predicted with those annotated by radiologists using contrast-enhanced computed tomography (CECT) 24 hours post-treatment, considered the gold standard.
Phys Med Biol
January 2025
Department of Biomedical Engineering, University of Cincinnati, UC Bioscience Center, 3159 Eden Ave., Cincinnati, Ohio, 45221, UNITED STATES.
Ultrasound echo decorrelation imaging can successfully monitor and control thermal ablation of animal liver and tumor tissue ex vivo and in vivo. However, normal and diseased human liver has substantially different physical properties that affect echo decorrelation. Here, effects of human liver tissue condition on ablation guidance by three-dimensional echo decorrelation imaging are elucidated in experiments testing closed-loop control of radiofrequency ablation (RFA) in normal and diseased human liver tissue ex vivo.
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