Reproducibility and Optimal Arterial Input Function Selection in Dynamic Contrast‐Enhanced Perfusion MRI in the Healthy Brain

BACKGROUND: Dynamic contrast-enhanced MRI (DCE-MRI) has seen increasing use for quantification of low level of blood-brain barrier (BBB) leakage in various pathological disease states and correlations with clinical outcomes. However, currently there exists limited studies on reproducibility in healthy controls, which is important for the establishment of a normality threshold for future research. PURPOSE: To investigate the reproducibility of DCE-MRI and to evaluate the effect of arterial input function (AIF) selection and manual region of interests (ROI) delineation vs. automated global segmentation. STUDY TYPE: Prospective. POPULATION: A total of 16 healthy controls; 11 females; mean age 28.7 years (SD 10.1). FIELD STRENGTH/SEQUENCE: A 3T; GE DCE; 3D TFE T1WI. 2D TSE T2. ASSESSMENT: The influx constant Ki , a measure of BBB permeability, and Vp , the blood plasma volume, was calculated using the Patlak model. Cerebral blood flow (CBF) was calculated using Tikhonov model free deconvolution. Manual tissue ROIs, drawn by H.J.S. (30+ years of experience), were compared to automatic tissue segmentation. STATISTICAL TESTS: Intraclass correlation coefficient (ICC) and repeatability coefficient (RC) was used to assess reproducibility. Bland-Altman plots were used to evaluate agreement between measurements day 1 vs. day 2, and manual vs. segmentation method. RESULTS: Ki showed excellent reproducibility in both white and gray matter with an ICC between 0.79 and 0.82 and excellent agreement between manual ROI and automatic segmentation, with an ICC of 0.89 for Ki in WM. Furthermore, Ki values in gray and white matter conforms with histological tissue characteristics, where gray matter generally has a 2-fold higher vessel density. The highest reproducibility measures of Ki (ICC = 0.83), CBF (ICC = 0.77) and Vd (ICC = 0.83) was obtained with the AIF sampled in the internal carotid artery (ICA). DATA CONCLUSION: DCE-MRI shows excellent reproducibility of pharmacokinetic variables derived from healthy controls. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.