Shutter-Speed DCE-MRI Analyses of Human Glioblastoma Multiforme (GBM) Data

Background: The shutter-speed model dynamic contrast-enhanced (SSM-DCE) MRI pharmacokinetic analysis adds a metabolic dimension to DCE-MRI. This is of particular interest in cancers, since abnormal metabolic activity might happen. Purpose: To develop a DCE-MRI SSM analysis framework for glioblastoma multiforme (GBM) cases considering the heterogeneous tissue found in GBM. Study Type: Prospective. Subjects: Ten GBM patients. Field Strength/Sequence: 3T MRI with DCE-MRI. Assessments: The corrected Akaike information criterion (AIC_c) was used to automatically separate DCE-MRI data into proper SSM versions based on the contrast agent (CA) extravasation in each pixel. The supra-intensive parameters, including the vascular water efflux rate constant (k_bo), the cellular efflux rate constant (k_io), and the CA vascular efflux rate constant (k_pe), together with intravascular and extravascular–extracellular water mole fractions (p_b and p_o, respectively) were determined. Further error analyses were also performed to eliminate unreliable estimations on k_io and k_bo. Statistical Tests: Student's t-test. Results: For tumor pixels of all subjects, 88% show lower AIC_c with SSM than with the Tofts model. Compared to normal-appearing white matter (NAWM), tumor tissue showed significantly larger p_b (0.045 vs. 0.011, P < 0.001) and higher k_pe (3.0 × 10⁻² s⁻¹ vs. 6.1 × 10⁻⁴ s⁻¹, P < 0.001). In the contrast, significant k_bo reduction was observed from NAWM to GBM tumor tissue (2.8 s⁻¹ vs. 1.0 s⁻¹, P < 0.001). In addition, k_bo is four orders and two orders of magnitude greater than k_pe in the NAWM and GBM tumor, respectively. These results indicate that CA and water molecule have different transmembrane pathways. The mean tumor k_io of all subjects was 0.57 s⁻¹. Data Conclusion: We demonstrate the feasibility of applying SSM models in GBM cases. Within the proposed SSM analysis framework, k_io and k_bo could be estimated, which might be useful biomarkers for GBM diagnosis and survival prediction in future. Level of Evidence: 4. Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2020;52:850–863.