2018 AAPM Annual Meeting
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Session Title: Advanced DWI: Applications for Radiation Oncology
Question 1: Which of the following affects the calculated apparent diffusion coefficients (ADC)?
Reference:Chenevert TL. Principles of diffusion-weighted imaging (DW-MRI) as applied to body imaging. In “Diffusion-weighted MR Imaging: applications in the body”. Koh and Thoeny (Eds.). Spinger. 2010.
Choice A:The applied b-values in diffusion weighted imaging.
Choice B:The intravoxel incoherent motion (IVIM), or the microcapillary blood flow.
Choice C:The signal to noise ratio (SNR) of the DWI images.
Choice D:All of the above.
Question 2: Which of the following is NOT a typical application of diffusion weighted imaging (DWI):
Reference:Padhani AR, et al. Diffusion-weighted magnetic resonance imaging as a cancer biomarker: consensus and recommendations. Neoplasia. 11(2): 102–125. 2009.
Choice A:Early detection of ischemic stroke.
Choice B:Gadolinium contrast agent enhanced dynamic imaging of the liver.
Choice C:Detection of malignant tumors such as in whole body MRI and imaging of prostate cancer.
Choice D:Early assessment or prediction for the efficacy of treatment of cancer.
Question 3: Which of the following can cause geometric distortion on MRI image?
Reference:Walker, A., Liney, G. P., Metcalfe, P. E. & Holloway, L. C. (2014). MRI distortion: considerations for MRI based radiotherapy treatment planning. Australasian Physical & Engineering Sciences in Medicine, 37 (1), 103-113.
Choice A:Chemical shifts
Choice B:Inhomogeneity in magnetic field
Choice C:Gradient non-linearity
Choice D:All of the above
Choice E:None of the above
Question 4: Which of the following is not a challenge for using conventional DWI in the Viewray RTgRT system?
Reference:Y. Gao, F. Han, Z. Zhou, M. Cao, T. Kaprealian, M. Kamrava, M. Wang, J. Neylon, D. Low, Y. Yang, P. Hu, “Distortion-Free Diffusion MRI using an MRI-Guided Tri-Cobalt 60 Radiotherapy System: Sequence Validation and Preliminary Clinical Experience”, Med Phys. 2017 Jul 10. doi: 10.1002/mp.12465
Choice A:Biological changes, such as ADC change, often happen earlier than morphological change.
Choice B:Optimal timing of acquiring DWI.
Choice C:Low spatial resolution.
Choice D:Large geometric distortion.
Choice E:SNR loss causing inaccurate DWI with high b values.
Question 5: What are the limitations of applying voxel-based heterogeneity analysis of the ADC to predict the treatment outcome?
Reference:Rectal Cancer: Assessment of Neoadjuvant Chemoradiation Outcome based on Radiomics of Multiparametric MRI, K. Nie, L. Shi, Q. Chen, X. Hu, S.K. Jabbour, N. Yue, T. Niu, and X. Sun, Clin Cancer Res; 22(21) November 1, 2016
Choice A:The coarse imaging resolution could wash out the heterogeneity distribution of the ADC maps.
Choice B:The variations of the ADC values exist at the microstructure scale.
Choice C:The dependency of ADC on a variety of histological features indicates it lacks biological specificity.
Choice D:All of the above.
Question 6: Which of the following is true for the prostate cancer:
Reference:Automatic classification of prostate cancer Gleason scores from multiparametric magnetic resonance images, D. Fehr, H. Veeraraghavan, A. Wibmer, T. Gondo, K. Matsumoto, H.A. Vargas, E. Sala, H. Hricak and J.O. Deasy, PNAS November 17, 2015. 112 (46) E6265-E6273
Choice A:The ADC maps can not be used to estimate the volumetric tumour cell density distribution.
Choice B:The texture features derived from the ADC can improve the classification power for differentiating cancers by the aggressiveness.
Choice C:Considering the low signal noise ratio of the DWI, the second order texture features generated from the ADC map lacks clinical benefits.
Choice D:The texture feature sets derived from the ADC map has equal contributions to classification performance and should be all included in the classifier.
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