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Feasibility of abdomino‐pelvic T1‐weighted real‐time thermal mapping of laser ablation
Author(s) -
Dick Elizabeth A.,
Wragg Paul,
Joarder Rita,
de Jode Michael,
Lamb Gabrielle,
Gould Stuart,
Gedroyc Wladyslaw M.W.
Publication year - 2003
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.10242
Subject(s) - thermal ablation , ablation , magnetic resonance imaging , medicine , laser ablation , laser , grayscale , materials science , nuclear medicine , radiology , pixel , physics , optics
Purpose To prove the hypothesis that T1‐weighted (T1W) thermal mapping is reliable and achievable in magnetic resonance (MR)‐guided laser tumor ablation. Materials and Methods Near real‐time gray and color‐scale T1W thermal maps in 111 MR‐guided laser thermal ablations (LTA) of liver, kidney, and uterine tumors were studied. After laser fiber placement, near real‐time gray and color‐scale thermal maps were produced. Previous work showed T1 signal is inversely proportional to temperature below 55°C (the point of irreversible necrosis). Results Thermal mapping was successful in 84% of uterine, 74% of hepatic, and 20% of renal ablations. For hepatic and uterine tumors, size and conspicuity of thermal lesions were significantly greater on subtracted colorized images rather than gray‐scale raw image mapping ( P = 0.001, paired Student's t‐test). Patient movement ( N = 24), fiber charring N = 2), magnetic field distortion, and reconstruction errors ( N = 2) caused mapping failure. For both renal and hepatic tumors, comparison of near real‐time T1W colorized thermal map and follow up gadolinium‐enhanced MR imaging revealed moderate correlation (Pearson correlation coefficient of 0.55 and 0.5, respectively). Conclusion In hepatic, renal, and uterine thermal maps, the color scale produced significantly greater sized lesions with significantly greater conspicuity than the gray scale. T1W thermal mapping was reliable and successfully achieved in 73.7% of procedures, and predicted the ablated area of the tumor moderately well. J. Magn. Reson. Imaging 2003;17:197–205. © 2003 Wiley‐Liss, Inc.