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Characterization of edema after cryo and radiofrequency ablations based on serial magnetic resonance imaging.

ABSTRACT: INTRODUCTION:Radiofrequency (RF) and cryoablation are routinely used to treat arrhythmias, but the extent and time course of edema associated with the two different modalities is unknown. Our goal was to follow the lesion maturation and edema formation after RF and cryoablation using serial magnetic resonance imaging (MRI). METHODS AND RESULTS:Ventricular ablation was performed in a canine model (n?=?11) using a cryo or an irrigated RF catheter. T2-weighted (T2w) edema imaging and late gadolinium enhancement (LGE)-MRI were done immediately (0?day: acute), 1 to 2 weeks (subacute), and 8 to 12 weeks (chronic) after ablation. After the final MRI, excised hearts underwent pathological evaluation. As a result, 45 ventricular lesions (cryo group: 20; RF group: 25) were evaluated. Acute LGE volume was not significantly different but acute edema volume in cryo group was significantly smaller (1225.0?±?263.5 vs 1855.2?±?520.5?mm3 ; P?=?0.01). One week after ablation, edema still existed in both group but was similar in size. Two weeks after ablation there was no edema in either of the groups. In the chronic phase, the lesion volume for cryo and RF in LGE-MRI (296.7?±?156.4 vs 281.6?±?140.8?mm3 ; P?=?0.73); and pathology (243.3?±?125.9 vs 214.5?±?148.6?mm3 ; P?=?0.49), as well as depth, was comparable. CONCLUSIONS:When comparing cryo and RF lesions of similar chronic size, acute edema is larger for RF lesions. Edema resolves in both cryo and RF lesions in 1 to 2 weeks.

SUBMITTER: Yamashita K

PROVIDER: S-EPMC6363882 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature

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Characterization of edema after cryo and radiofrequency ablations based on serial magnetic resonance imaging.

Yamashita Kennosuke K Kholmovski Eugene E Ghafoori Elyar E Kamali Roya R Kwan Eugene E Lichter Justin J MacLeod Robert R Dosdall Derek J DJ Ranjan Ravi R

Journal of cardiovascular electrophysiology 20181121 2

<h4>Introduction</h4>Radiofrequency (RF) and cryoablation are routinely used to treat arrhythmias, but the extent and time course of edema associated with the two different modalities is unknown. Our goal was to follow the lesion maturation and edema formation after RF and cryoablation using serial magnetic resonance imaging (MRI).<h4>Methods and results</h4>Ventricular ablation was performed in a canine model (n = 11) using a cryo or an irrigated RF catheter. T2-weighted (T2w) edema imaging and ...[more]

PMID: 30375090

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Project description:ImportanceCharacterizing longitudinal patterns of regional brain volume changes in a population with normal cognition at the individual level could improve understanding of the brain aging process and may aid in the prevention of age-related neurodegenerative diseases.ObjectiveTo investigate age-related trajectories of the volumes and volume change rates of brain structures in participants without dementia.Design, setting, and participantsThis cohort study was conducted from November 1, 2006, to April 30, 2021, at a single academic health-checkup center among 653 individuals who participated in a health screening program with more than 10 years of serial visits.ExposureSerial magnetic resonance imaging, Mini-Mental State Examination, health checkup.Main outcomes and measuresVolumes and volume change rates across brain tissue types and regions.ResultsThe study sample included 653 healthy control individuals (mean [SD] age at baseline, 55.1 [9.3] years; median age, 55 years [IQR, 47-62 years]; 447 men [69%]), who were followed up annually for up to 15 years (mean [SD], 11.5 [1.8] years; mean [SD] number of scans, 12.1 [1.9]; total visits, 7915). Each brain structure showed characteristic age-dependent volume and atrophy change rates. In particular, the cortical gray matter showed a consistent pattern of volume loss in each brain lobe with aging. The white matter showed an age-related decrease in volume and an accelerated atrophy rate (regression coefficient, -0.016 [95% CI, -0.012 to -0.011]; P < .001). An accelerated age-related volume increase in the cerebrospinal fluid-filled spaces, particularly in the inferior lateral ventricle and the Sylvian fissure, was also observed (ventricle regression coefficient, 0.042 [95% CI, 0.037-0.047]; P < .001; sulcus regression coefficient, 0.021 [95% CI, 0.018-0.023]; P < .001). The temporal lobe atrophy rate accelerated from approximately 70 years of age, preceded by acceleration of atrophy in the hippocampus and amygdala.Conclusions and relevanceIn this cohort study of adults without dementia, age-dependent brain structure volumes and volume change rates in various brain structures were characterized using serial magnetic resonance imaging scans. These findings clarified the normal distributions in the aging brain, which are essential for understanding the process of age-related neurodegenerative diseases.

Project description:BACKGROUND:Myocardial edema in acute myocardial infarction (AMI) is commonly imaged using dark-blood short tau inversion recovery turbo spin echo (STIR-TSE) cardiovascular magnetic resonance (CMR). The technique is sensitive to cardiac motion and coil sensitivity variation, leading to myocardial signal nonuniformity and impeding reliable depiction of edematous tissues. T2-prepared balanced steady state free precession (T2p-bSSFP) imaging has been proposed, but its contrast is low, and averaging is commonly needed. T2 mapping is useful but requires a long scan time and breathholding. We propose here a single-shot magnetization prepared sequence that increases the contrast between edema and normal myocardium and apply it to myocardial edema imaging. METHODS:A magnetization preparation module (T2STIR) is designed to exploit the simultaneous elevation of T1 and T2 in edema to improve the depiction of edematous myocardium. The module tips magnetization down to the -z axis after T2 preparation. Transverse magnetization is sampled at the fat null point using bSSFP readout and allows for single-shot myocardial edema imaging. The sequence (T2STIR-bSSFP) was studied for its contrast behavior using simulation and phantoms. It was then evaluated on 7 healthy subjects and 7 AMI patients by comparing it to T2p-bSSFP and T2 mapping using the contrast-to-noise ratio (CNR) and the contrast ratio as performance indices. RESULTS:In simulation and phantom studies, T2STIR-bSSFP had improved contrast between edema and normal myocardium compared with the other two edema imaging techniques. In patients, the CNR of T2STIR-bSSFP was higher than T2p-bSSFP (5.9?±?2.6 vs. 2.8?±?2.0, P?<?0.05) but had no significant difference compared with that of the T2 map (T2 map: 6.6?±?3.3 vs. 5.9?±?2.6, P?=?0.62). The contrast ratio of T2STIR-bSSFP (2.4?±?0.8) was higher than that of the T2 map (1.3?±?0.1, P?<?0.01) and T2p-bSSFP (1.4?±?0.5, P?<?0.05). CONCLUSION:T2STIR-bSSFP has improved contrast between edematous and normal myocardium compared with commonly used bSSFP-based edema imaging techniques. T2STIR-bSSFP also differentiates between fat that was robustly suppressed and fluids around the heart. The technique is useful for single-shot edema imaging in AMI patients.

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Characterization of edema after cryo and radiofrequency ablations based on serial magnetic resonance imaging.

Publications

Characterization of edema after cryo and radiofrequency ablations based on serial magnetic resonance imaging.

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