Andrea S Doria1, Paul Dick. 1. Department of Diagnostic Imaging, The Hospital for Sick Children, 555 University Avenue, University of Toronto, Toronto, ON, Canada M5G1X8. andrea.doria@sickkids.ca
Abstract
RATIONALE AND OBJECTIVES: BOLD MRI provides functional information based on minimal changes. Problems inherent in data processing of the very low signal-to-noise-ratio of BOLD experiments have created obstacles for validation of certain techniques using standard strength-field MR scanners. Measures of diagnostic accuracy of clustered data are directly related to the reading parameters used to define regions-of-interest (ROIs). Our primary aim was to determine the combination of ROI-related reading parameters that provides highest accuracy for discrimination of presence or absence of arthritis in acute and subacute stages of the disease using paired comparisons of BOLD MRI data. MATERIALS AND METHODS: Six male New Zealand white rabbits were injected with albumin into one knee and saline into the contralateral knee, 3 animals had albumin injected into only one of the knees, 2 had saline injected into one of the knees, and 3 animals were not injected. The rabbits' knees underwent BOLD MRI on days 1 and 28 after induction of arthritis, except for the knees of 3 animals (albumin- vs saline-injected knees, n = 2 animals; saline- vs noninjected knees, n = 1 animal) that died before expected and had only the first MRI examination done. Percentage of activated voxels and differences in on-and-off signal intensities were the BOLD MRI methods applied. Data were analyzed using anatomic-driven small ROI, voxel-chaser-driven small ROI and anatomic-driven large ROI techniques. RESULTS: Diagnostic areas-under-the curve (AUCs) were obtained only for acute arthritis and only when percentage of activated voxels was used. Low threshold, positive voxel activations and small ROIs generated the largest AUCs (AUC +/- SE, .911 +/- .092, P = .014) using either anatomic-driven or voxel-chaser-driven techniques. A sensitivity analysis confirmed the importance of threshold as a parameter for analysis. CONCLUSION: Low threshold, positive voxel activations and small ROIs constituted the set of reading parameters that provided the most accurate BOLD MRI results.
RATIONALE AND OBJECTIVES: BOLD MRI provides functional information based on minimal changes. Problems inherent in data processing of the very low signal-to-noise-ratio of BOLD experiments have created obstacles for validation of certain techniques using standard strength-field MR scanners. Measures of diagnostic accuracy of clustered data are directly related to the reading parameters used to define regions-of-interest (ROIs). Our primary aim was to determine the combination of ROI-related reading parameters that provides highest accuracy for discrimination of presence or absence of arthritis in acute and subacute stages of the disease using paired comparisons of BOLD MRI data. MATERIALS AND METHODS: Six male New Zealand white rabbits were injected with albumin into one knee and saline into the contralateral knee, 3 animals had albumin injected into only one of the knees, 2 had saline injected into one of the knees, and 3 animals were not injected. The rabbits' knees underwent BOLD MRI on days 1 and 28 after induction of arthritis, except for the knees of 3 animals (albumin- vs saline-injected knees, n = 2 animals; saline- vs noninjected knees, n = 1 animal) that died before expected and had only the first MRI examination done. Percentage of activated voxels and differences in on-and-off signal intensities were the BOLD MRI methods applied. Data were analyzed using anatomic-driven small ROI, voxel-chaser-driven small ROI and anatomic-driven large ROI techniques. RESULTS: Diagnostic areas-under-the curve (AUCs) were obtained only for acute arthritis and only when percentage of activated voxels was used. Low threshold, positive voxel activations and small ROIs generated the largest AUCs (AUC +/- SE, .911 +/- .092, P = .014) using either anatomic-driven or voxel-chaser-driven techniques. A sensitivity analysis confirmed the importance of threshold as a parameter for analysis. CONCLUSION: Low threshold, positive voxel activations and small ROIs constituted the set of reading parameters that provided the most accurate BOLD MRI results.
Authors: Andrea S Doria; Adrian Crawley; Harpal Gahunia; Rahim Moineddin; Tammy Rayner; Vivian Tassos; Anguo Zhong; Kenneth Pritzker; Maria Mendes; Roland Jong; Robert B Salter Journal: Pediatr Radiol Date: 2011-08-05
Authors: Otilia C Nasui; Michael W Chan; George Nathanael; Adrian Crawley; Elka Miller; Jaques Belik; Hai-Ling Cheng; Andrea Kassner; Tammy Rayner; Ruth Weiss; Garry Detzler; Anguo Zhong; Rahim Moineddin; Roland Jong; Marianne Rogers; Andrea S Doria Journal: Eur Radiol Date: 2014-09-04 Impact factor: 5.315
Authors: Michael W Chan; George Nathanael; Antonella Kis; Afsaneh Amirabadi; Anguo Zhong; Tammy Rayner; Ruth Weiss; Garry Detzler; Roland Jong; Harpal Gahunia; Rahim Moineddin; Adrian Crawley; Andrea S Doria Journal: Pediatr Radiol Date: 2013-12-24
Authors: Andrea S Doria; Adrian Crawley; Paul Babyn; Tammy Rayner; Marjorie McLimont; Rahim Moineddin; Ronald Laxer; Brian Feldman Journal: Clinics (Sao Paulo) Date: 2013-05 Impact factor: 2.365