title: Thermal lesion conspicuity following interstitial radiofrequency thermal tumor ablation in humans: a comparison of STIR, turbo spin-echo T2-weighted, and contrast-enhanced T1-weighted MR images at 0.2 T.
abstract: The purpose of this study was to compare the contrast between radiofrequency (RF) thermal liver lesions and surrounding tissue in T2-weighted turbo spin-echo sequences (TSE T2), short TI inversion recovery techniques (STIR), and contrast-enhanced (CE) T1-weighted spin-echo images. Nineteen RF thermal ablations were performed on eight patients with metastatic liver tumors. After ablation, contrast-to-noise ratios (CNRs) were calculated between mean signal amplitudes from three regions of interest (ROI) (lesion, surrounding edema, and normal tissue) using TSE T2-weighted, STIR, and contrast-enhanced T1-weighted (CE T1) sequences for each lesion. CNRs between the thermal lesion and normal liver tissue for both TSE T2-weighted (mean 0.9) and STIR (2.0) images were significantly lower than for CE T1-weighted (8.4) images (t-test, alpha = 0.05). However, CNRs between edema rim and the core of the thermal lesion for both TSE T2-weighted (8.1) and STIR images (7.2) were not significantly different (t-test, alpha = 0.05) from CNRs between lesion and normal tissue for CE T1-weighted images (8.4), nor was the CNR between edema rim and normal tissue for both TSE T2-weighted (10.3) and STIR (9.8) images. Although the edema was not visible on CE T1-weighted images, 18 of 19 lesions (94.7%) were surrounded by a hyperintense rim on TSE T2-weighted or STIR images. Both TSE T2-weighted and STIR sequences represent valid techniques for repeatable assessment of RF thermal lesions.
authors.affiliation: Department of Radiology, University Hospitals of Cleveland/Case Western Reserve University, Cleveland, Ohio 44106, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Aschoff
authors.forename: N
authors.initials: N
authors.lastname: Rafie
authors.forename: J A
authors.initials: JA
authors.lastname: Jesberger
authors.forename: J L
authors.initials: JL
authors.lastname: Duerk
authors.forename: J S
authors.initials: JS
authors.lastname: Lewin
mesh_terms: D000328:Adult; D000368:Aged; D017115:Catheter Ablation; D003287:Contrast Media; D005260:Female; D006801:Humans; D006979:Hyperthermia, Induced; D008099:Liver / Q000473:pathology; D008113:Liver Neoplasms / Q000473:pathology / Q000556:secondary / Q000628:therapy*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged
chemical_list: D003287:Contrast Media