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MR Imaging Parameters for Noninvasive Prediction of EGFR Amplification in IDH-Wildtype Lower-Grade Gliomas: A Multicenter Study
Yae Won Park1, Ji Eun Park2, Sung Soo Ahn1, Seung Hong Choi3, Ho Sung Kim2, and Seung-Koo Lee1
1Yonsei University College of Medicine, Seoul, Korea, Republic of, 2University of Ulsan College of Medicine, Seoul, Korea, Republic of, 3Seoul National University Hospital, Seoul, Korea, Republic of

Synopsis

Epidermal growth factor receptor (EGFR) amplification status of isocitrate dehydrogenase-wildtype (IDHwt) lower-grade gliomas (LGGs; grade II/III) is one of the key molecular markers for diagnosing molecular glioblastoma. Our study shows that infiltrative or mixed pattern, lower ADC, lower 5th percentile of ADC, and higher 95th percentile of nCBF may be useful imaging biomarkers for the EGFR amplification of IDHwt LGGs. Moreover, quantitative imaging biomarkers may add value to qualitative imaging parameters (with AUCs of 0.71 and 0.88, p = 0.020).

Abstract

Background: Epidermal growth factor receptor (EGFR) amplification status of isocitrate dehydrogenase-wildtype (1IDHwt) lower-grade gliomas (LGGs; grade II/III) is one of the key molecular markers for diagnosing molecular glioblastoma.

Objective: To identify noninvasive imaging parameters from diffusion-weighted imaging and dynamic susceptibility contrast (DSC) imaging to predict the EGFR amplification status of IDHwt LGGs.

Methods: A total of 86 IDHwt LGG patients with known EGFR amplification status (62 non-amplified, 24 amplified) from three tertiary institutions were included. Qualitative imaging features as well as the quantitative imaging features such as the histogram parameters from apparent diffusion coefficient (ADC), normalized cerebral blood volume (nCBV), and normalized cerebral blood flow (nCBF) were assessed. Univariable and multivariable logistic regression models were constructed.

Results: On multivariable analysis, infiltrative or mixed pattern (OR = 5.47, p = 0.017), mean ADC (OR = 0.01, p = 0.043), 5th percentile of ADC (OR = 0.01, p = 0.017), and 95th percentile of nCBF (OR = 1.26, p = 0.025) were independent predictors of EGFR amplification. The diagnostic performance of the model with qualitative imaging parameter significantly increased when quantitative imaging parameters were added, with area under the curves of 0.71 and 0.88, respectively (p = 0.020).

Conclusion: Infiltrative or mixed pattern, lower ADC, lower 5th percentile of ADC, and higher 95th percentile of nCBF may be useful imaging biomarkers for the EGFR amplification of IDHwt LGGs. Moreover, quantitative imaging biomarkers may add value to qualitative imaging parameters.

Acknowledgements

None.

References

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Figures

Figure 1. Images of a 75-year-old female with an EGFR amplified grade III IDHwt glioma reveals T2 hyperintense tumor in the right frontal lobe, showing an infiltrative pattern (size of precontrast T1 abnormality much smaller than size of FLAIR abnormality). The histogram and cumulative histogram (dark blue line) of ADC shows a 5th percentile DC value and mean ADC value of 0.60 x 10-3 mm2/s and 1.01 x 10-3 mm2/s, respectively. The histogram and cumulative histogram (dark blue line) of nCBF shows a 95th percentile of the nCBF value of 7.54.

Figure 2. Images of a 58-year-old female with an EGFR non-amplified grade III IDHwt glioma reveals T2 hyperintense tumor in the left temporal lobe, showing an expansile pattern (size of precontrast T1 abnormality approximates size of FLAIR abnormality). The histogram and cumulative histogram (dark blue line) of ADC shows a 5th percentile ADC value and mean ADC value of 0.73 x 10-3 mm2/s and 1.28 x 10-3 mm2/s, respectively. The histogram and cumulative histogram (dark blue line) of nCBF shows a 95th percentile of the nCBF value of 4.55.

Proc. Intl. Soc. Mag. Reson. Med. 29 (2021)
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