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Multimodality imaging to assess immediate response to irreversible electroporation in a rat liver tumor model. Radiology 2014 Jun;271(3):721-9

Date

02/22/2014

Pubmed ID

24555632

Pubmed Central ID

PMC4263650

DOI

10.1148/radiol.14130989

Scopus ID

2-s2.0-84901676315   22 Citations

Abstract

PURPOSE: To compare changes on ultrasonographic (US), computed tomographic (CT), and magnetic resonance (MR) images after irreversible electroporation (IRE) ablation of liver and tumor tissues in a rodent hepatoma model.

MATERIALS AND METHODS: Studies received approval from the institutional animal care and use committee. Forty-eight rats were used, and N1-S1 tumors were implanted in 24. Rats were divided into groups and allocated for studies with each modality. Imaging was performed in normal liver tissues and tumors before and after IRE. MR imaging was performed in one group before and after IRE after hepatic vessel ligation. US images were graded to determine echogenicity changes, CT attenuation was measured (in Hounsfield units), and MR imaging signal-to-noise ratio (SNR) was measured before and after IRE. Student t test was used to compare attenuation and SNR measurements before and after IRE (P < .05 indicated a significant difference).

RESULTS: IRE ablation produced greater alterations to echogenicity in normal tissues than in tumors. Attenuation in ablated liver tissues was reduced compared with that in control tissues (P < .001), while small attenuation differences between ablated (42.11 HU ± 2.11) and control (45.14 HU ± 2.64) tumors trended toward significance (P = .052). SNR in ablated normal tissues was significantly altered after IRE (T1-weighted images: pre-IRE, 145.95 ± 24.32; post-IRE, 97.80 ± 18.03; P = .004; T2-weighted images, pre-IRE, 47.37 ± 18.31; post-IRE, 90.88 ± 37.15; P = .023). In tumors, SNR differences before and after IRE were not significant. No post-IRE signal changes were observed after hepatic vessel ligation.

CONCLUSION: IRE induces rapid changes on gray-scale US, unenhanced CT, and MR images. These changes are readily visible and may assist a performing physician to delineate ablation zones from the unablated surrounding parenchyma.

Author List

Zhang Y, White SB, Nicolai JR, Zhang Z, West DL, Kim DH, Goodwin AL, Miller FH, Omary RA, Larson AC

Author

Sarah B. White MD, MS, FSIR, FCIRSE Vice Chair, Professor in the Radiology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Contrast Media
Disease Models, Animal
Electroporation
Liver Neoplasms, Experimental
Magnetic Resonance Imaging
Male
Microscopy, Electron
Microscopy, Fluorescence
Multimodal Imaging
Rats
Rats, Sprague-Dawley
Tomography, X-Ray Computed
Ultrasonography