FMRI moc profile
QIBA fMRI Subcommittee Profile Draft
March 22, 2010
Cathy Elsinger (co-chair)
Assumption: It is appropriate for the QIBA fMRI subcommittee to work towards development of technical and practical guidelines which cover data acquisition, statistical analysis and paradigm design procedures in order to reduce variability, increase repeatability and reliability in BOLD fMRI exam administration and the quantitative measures derived. An ultimate goal is to arrive at a set of quantitative measures that can be used to validate/verify appropriateness of stimulus paradigms and associated protocols for future clinical applications and clinical research trial applications.
Short Term Goal: QIBA fMRI subcommittee to establish guidelines and recommendations to optimize acquisition parameters, paradigm design, and statistical analysis for single-subject BOLD fMRI exams to increase quality control, clinical utility and characterize clinical uses of fMRI which are appropriate. Initial test case will be mapping of motor cortex for presurgical planning purposes.
Long Term Goal: Individual QIBA Profiles can address different use-cases, which could be expanded and addressed through different subgroups (e.g.,Presurgical planning endpoint involves risk assessment and predictive value assessment for patient undergoing surgery while a pharma/clinical trial involves therapeutic effects/response)
QIBA Profiles consist of:
1. Intended use (clinical context), e.g. risk assessment or clinical trials
2. Claims (level of performance, both state-of-the-art and areas for improvement)
3. Protocol (structure provided by UPICT template)
4. Compliance check
QIBA Profile Draft:
Intended Use: fMRI is used as a tool for presurgical planning in patients undergoing brain surgery. The location of the brain tissue to be resected determines the particular region or regions of the brain to be investigated and the stimulus paradigm(s) selected (e.g. motor task, language task). The change in BOLD signal (relative to a rest condition) provides information about the brain region(s) involved in task performance and the proximity of this eloquent cortex to brain tissue to be resected. Presurgical planning endpoints involve risk assessment (how close is tissue to be resected to areas of eloquent cortex) and predictive value assessment (will removal of eloquent cortex result in a deficit) that influence patient surgery. Our goal is to determine the quantitative value of BOLD fMRI as predictor of cortical function and/or essential function and thus a medically meaningful surrogate for change in brain activity - a valid imaging biomarker.
Claim 1 – with the appropriate MR compatible peripheral equipment and software for stimulus delivery, patients can perform cognitive or sensorimotor tasks while they are in the MR scanner, and this behavior can be measured.
Claim 2 – the behavior elicited from the patient can be synchronized with MR image acquisition using the appropriate pulse sequence and the statistical result (change in MR signal) can be measured.
Claim 3 – The statistical result (change in MR signal) is quantifiable in terms of (1) magnitude of task-related activity relative to baseline with a statistical parameter such as F or T (and its p value); (2) temporal correlation of the signal with the task timing; (3) the spatial pattern of activation (density, clustering); and (4) proximity to a site of pathology or proposed resection margin.
Subgoals for development activities:
1. Guidelines for acquisition of fMRI data for presurgical mapping (claims 1 & 2)
2. Guidelines for processing and statistical analysis of data (quality control analysis and determination of degree of tolerable variability, i.e., what is clinically acceptable variance?) (claim 3)
3. Guidelines for design of clinically appropriate task paradigms based on clinical application, e.g. motor mapping (what are feasible motor task for motor cortex?) or language mapping (what are feasible language paradigms for laterality?)
4. Explore methodology (optimal vs. workable); QIBA reflects a bull’s eye approach of acceptable, target and ideal performance levels
How do we develop a roadmap for the groundwork to be done in terms of the characterizing the technical standards or methodology to be detailed, determining the accuracy and reproducibility of the measures acquired or the level of performance that would be considered acceptable, thus improving the clinical efficacy of fMRI exams?
Retrospective - What current state of the art is as reflected in the literature?
Collaborative analytical work with data derived from the ASFNR study?