Abstract Details

Title Reliability of Quantitative Brain Imaging Biomarkers

Topic Neuro-oncology

Presentation(s) P3 - Poster Session 3 (12:00 PM-1:00 PM)

Poster/Presentation
Number 13-001

Objective

Our objective is to design a statistical method to evaluate the level of change in the brain regional biological parameter and help us interpret it as a real biological change or as a measurement error.

Background In the repeatability analysis, when the measurement is the mean value of a parametric map within a region of interest (ROI), the ROI size becomes important as by increasing the size, the measurement will have a smaller variance. This is important in decision-making in prospective clinical studies of brain when the ROI size is variable, e.g., in monitoring the effect of treatment on lesions by quantitative MRI, and in particular when the ROI is small, e.g., in the case of brain lesions in multiple sclerosis. Thus, methods to estimate repeatability measures for arbitrary sizes of ROI are desired.

Design/Methods We propose a statistical model of the values of parametric map within the ROI and a method to approximate the model parameters, based on which we estimate repeatability coefficient for an ROI with an arbitrary size. Experiments are conducted on simulated data as well as on scan-rescan brain MRI of healthy subjects. Simulated data are generated by a set of model parameters (ground truth) and the parameters are estimated and compared with the ground truth.

Results The experiments show that the repeatability coefficient significantly varies with the ROI size in studies with small ROIs, such as in voxel-wise analysis of brain imaging biomarkers and monitoring the small lesions. In addition, the results show that the proposed method accurately estimates the model parameters

Conclusions

Repeatability coefficient needs to be correctly estimated based on the ROI size in studies with small ROIs. The main application of this study is the adjustment of the decision threshold based on the lesion size in treatment monitoring.

Authors/Disclosures
Fatemeh Hajighasemi, MD (University of California Irvine) PRESENTER	No disclosure on file
	No disclosure on file
	No disclosure on file
Bruce R. Rosen, MD (Massachusetts General Hosp.)	No disclosure on file

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