DCE-MRI V.2, Consensus QIBA Profile

The goal of the DCE-MRI quantification QIBA Profile version 2.0 is to provide an update from the Dynamic Contrast Enhanced MRI (DCE-MRI) Quantification profile (version 1.0, dated July 1, 2012) in order to include the use of 3 Tesla (T) MRI and the use of parallel imaging with receiver coil arrays. While many pharmacokinetic models have been described, this QIBA Profile (DCE-MRI Quantification) specifically addresses the physiological parameter Ktrans derived from the Tofts or generalized kinetic model (GKM) (1), which is correlated with the vessel (surface/area product and permeability) and haemodynamic (flow) properties. Tofts et al. introduced an extended Tofts model or extended GKM (eGKM), including a signal contribution from the arteries to cover tissue with higher vascularization (1). DCE-MRI is recognized as a potential method to provide predictive, prognostic, and/or physiological response biomarkers for cancer (2–10). This potential has been obtained despite considerable variation in the methods used for acquisition and analysis of the DCE-MRI data. This suggests there are substantial physiological differences (i.e., benign vs. malignant or non-responsive vs. responsive tumors) underlying these observations. Thus, there is potential value recognized in the integration of DCE-MRI for basic research, drug development, clinical research, and in routine clinical practice. However, in order to fulfill the promise of using DCE-MRI as a clinically useful tool, it is essential that common quantitative endpoints are used and that results are independent of imaging platforms, clinical sites, and time. Update to include 3T: With the inclusion of 3T MRI, we have introduced “recommended” procedures to calibrate and compensate for radio frequency (RF) transmit (or B1 + field) inhomogeneity, described in the subsequent sections. At 3T, this calibration is ideally utilized to obtain the desired precision of the resulting DCE-MRI biomarkers in the breast and prostate, and this finding is expected to generalize to all other body parts (11,12). This profile also contains an Appendix with recommended vendor-specific procedures for acquiring the requisite calibration information. Update to include Parallel Imaging: The inherent trade-offs between temporal and spatial resolution can be improved by using parallel imaging techniques to accelerate acquisition. But, the use of parallel imaging comes at the expense of signal-to-noise ratio (SNR) and potential artifacts. Nevertheless, modest acceleration factors are beneficial in the context of DCE-MRI and a range of acceleration factors are described in this profile. Profile development is an evolutionary, phased process; this Profile is in the Public Comment Resolution Draft stage. The performance claims represent expert consensus and will be empirically demonstrated at a subsequent stage. Users of this Profile are encouraged to refer to the following site to understand the document’s context: http://qibawiki.rsna.org/index.php/QIBA_Profile_Stages. The Claim (Section 2) describes the biomarker performance. The biomarker performance claims are derived from the body of scientific literature that have presented test-retest studies meeting scientific requirements. The Activities (Section 3) contribute to generating the biomarker. Requirements are placed on the Actors that participate in those activities as necessary to achieve the Claim. Assessment Procedures (Section 4) for evaluating specific requirements are defined as needed to ensure acceptable performance. Conformance (Section 5) regroups Section 3 requirements by the Actor to conveniently check Conformance to the profile. This document is intended to help imaging staff generating this biomarker, vendor staff developing related products, purchasers of such products, clinicians who are using this biomarker to aid in clinical decisions, and researchers using this imaging biomarker as an endpoint measure within clinical trials. Note that this document states requirements to achieve the specified Claims and does not reflect “standard of care” requirements for DCE-MRI. Due to the limited availability of test-retest studies, some of the Claims were achieved based on protocols that are outdated relative to the currently available imaging capabilities. Therefore, this profile also provides recommendations based on consensus by the DCE-MRI committee that reflect current quantitative DCE-MRI practices. Conformance to this Profile is secondary to properly caring for the patient.