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Quantitative analysis of whole‐tumor Gd enhancement histograms predicts malignant transformation in low‐grade gliomas
Author(s) -
Tofts Paul S.,
Benton Christopher E.,
Weil Rimona S.,
Tozer Daniel J.,
Altmann Daniel R.,
Jäger H. Rolf,
Waldman Adam D.,
Rees Jeremy H.
Publication year - 2007
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.20800
Subject(s) - fluid attenuated inversion recovery , medicine , histogram , nuclear medicine , transformation (genetics) , malignant transformation , radiology , magnetic resonance imaging , pathology , computer science , artificial intelligence , chemistry , biochemistry , gene , image (mathematics)
Purpose To quantify subtle gadolinium (Gd) enhancement (signal increase) in whole‐tumor histograms and optimize their ability to predict subsequent malignant transformation in low‐grade gliomas (LGGs). Materials and Methods We analyzed histograms from 21 adult subjects with LGGs (eight nontransformers and 13 transformers) who had been imaged every six months for periods of two to five years. Before transformation these tumors were reported as radiologically non‐enhancing. Imaging included a T 1 ‐weighted volume sequence before and after a double dose of Gd‐DTPA contrast agent. Image data sets were spatially registered and subtracted to obtain maps of percent enhancement (%E). Tumor outlines were defined on fluid‐attenuated inversion recovery (FLAIR) images, and the volumes were calculated. Histogram tails were analyzed to obtain the volume (mL) of subtly enhancing tissue (%E > 10%). Results Baseline enhancing volumes were higher for Ts than for NTs ( P < 0.005). Kaplan‐Meier survival curves for a threshold of 4 mL showed clear differences at five years ( P < 0.04). Pretransformation examinations predicted transformation (corrected threshold = 3.0 mL, P = 0.011). Conclusion Clear histogram differences at presentation suggest that the process of transformation starts very early. It is now possible to identify individuals at high risk for transformation at baseline by quantifying the volume of subtly enhancing tumor tissue, and such findings could have an impact on patient management. J. Magn. Reson. Imaging 2007. © 2006 Wiley‐Liss, Inc.