One-Year Test-Retest Reliability of Intrinsic Connectivity Network fMRI in Older Adults (P03.082)

Abstract

Objective: To evaluate long-term reliability of intrinsic connectivity analytical strategies in older subjects and their potential use as disease-monitoring biomarkers. Background “Resting-state” or task-free fMRI can assess intrinsic connectivity network (ICN) integrity in health and disease, suggesting a potential for use of these methods as disease-monitoring biomarkers. Numerous analytical options are available, including model-driven ROI-based correlation analysis and model-free, independent component analysis (ICA). High test-retest reliability will be a necessary feature of a successful ICN biomarker, yet available reliability data remains limited. Design/Methods: 24 healthy older controls were recruited through the UCSF Memory and Aging Center and underwent two sessions of task-free functional MR imaging roughly one year apart. One ICN, the salience network, was examined using a series of analytical strategies. Test-retest reliability was measures by intraclass coefficients (ICC) of ICN scores across the two sessions. Results: Most ICN analytical methods proved reliable (ICC > 0.4) and were improved by wavelet analysis. Seed-based ROI correlation analysis showed high map-wise reliability, whereas graph theoretical measures and temporal concatenation group ICA produced the most reliable individual unit-wise outcomes. Including global signal regression in ROI-based correlation analyses reduced reliability. Conclusions: Our study provides a direct comparison between the most commonly used ICN fMRI methods and potential guidelines for measuring intrinsic connectivity in aging control and patient populations over time. Disclosure: Dr. Guo has nothing to disclose. Dr. Kurth has nothing to disclose. Dr. Zhou has nothing to disclose. Dr. Mayer has nothing to disclose. Dr. Eickhoff has nothing to disclose. Dr. Kramer has nothing to disclose. Dr. Seeley has received personal compensation for activities with Korea Novartis.