BACKGROUND: Currently, no definitive method reliably differentiates pseudoprogression from true progression. Misclassification can either halt effective therapy or prolong ineffective treatment. We hypothesized that the diagnostic accuracy could be improved using quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) after error correction via point-of-care portable perfusion phantoms (P4s). This study aimed to develop a P4 for quantitative DCE-MRI of the brain and enhance accuracy in distinguishing between pseudo and true glioblastoma progression. METHODS: Twelve patients with potential glioblastoma progression after adjuvant chemoradiation therapy were recruited. Each subject underwent two DCE-MRI exams within a week using a single 3T MRI scanner. Quantitative DCE-MRI parameters were retrieved based on the extended Tofts model (ETM), Tofts model (TM), and shutter speed model (SSM) before and after P4-based error correction. The consistency of the pharmacokinetic (PK) parameter measurements was evaluated based on the within-subject coefficient of variation (wCV) before and after P4-based error correction. Glioblastoma progression status was determined using the Response Assessment in Neuro-Oncology (RANO) criteria about five months after DCE-MRI exams. RESULTS: Among the participants, five had true progression, and seven had pseudoprogression. The wCVs of the CONCLUSIONS: Following P4-based error correction, a quantitative DCE-MRI parameter,