Can the apparent diffusion coefficient be used as a noninvasive parameter to distinguish tumor tissue from
Dirk Pauleit1, Karl-Josef Langen, Frank Floeth
1Clinic for Nuclear Medicine (KME), Research Center Jülich, Jülich, Germany. pauleit@web.de
Purpose:
To determine whether the apparent diffusion coefficient (ADC) can be used to distinguish between tumor tissue and peritumoral brain tissue in cerebral gliomas.
Materials And Methods:
Twenty-two patients with 44 biopsies were enrolled in this study. ADC maps calculated from a diffusion-weighted (DW) multislice EPI sequence were coregistered with conventional MR images. Neuronavigated biopsies and intraoperative markers were used for correlation with the histologic specimens. ADC values and lesion-to-brain ratios of the different sequences were calculated and compared for tumor tissue and peritumoral brain tissue. A logistic regression analysis was performed to determine the diagnostic value of the ADC maps.
Results:
The ADC values and ratios demonstrated a large overlap between tumor tissue and peritumoral tissue. Group comparisons revealed a significantly (P=0.03) lower ADC ratio in tumor tissue (mean=1.28 +/- 0.39) compared to peritumoral tissue (mean=1.48 +/- 0.30), whereas the absolute ADC values did not differ significantly. In the logistic regression analysis, the lesion-to-brain ratio of the gadolinium (Gd)-enhanced T1-weighted sequence was the most valuable predictor of the presence of tumor tissue. The ADC value and ratio were not identified as significant predictors.
Conclusion:
The ADC is not helpful for distinguishing tumor tissue from peritumoral brain tissue in gliomas.
