Quantitation of blood‐brain barrier defect by magnetic resonance imaging and gadolinium‐DTPA in patients with multiple sclerosis and brain tumors

Abstract

In this study quantitation of the degree of deficiency of the blood-brain barrier (BBB) in patients with multiple sclerosis or brain tumors, by using MRI, is shown to be possible. As a measure of permeability of the BBB to Gadolinium-DTPA (Gd-DTPA) the flux per unit of distribution volume per unit of brain mass was used. This quantity was found by introducing the longitudinal relaxation rate (R1) as a measure of concentration of Gd-DTPA in the brain tissue in the mathematical model for the transcapillary transport over the BBB. High accordance between the observed data points and the model was found, and the results were comparable to results obtained from similar studies using positron emission tomography. The improved possibility of quantitating the defect of the BBB by MRI may give new information about pathogenesis or etiology, and leads to improved methods in monitoring the efficacy of treatments in intracranial diseases.

Diffusion‐weighted and dynamic contrast‐enhanced MRI in evaluation of early treatment effects during neoadjuvant chemotherapy in breast cancer patients

“…This resulted in a total of 14 patients with baseline MRI (median 2 days before NAC; range, 0-6), and 12 patients with pre-and post-treatment MRI (median 21 days after the first NAC; range, [19][20][21]. The reduction in clinical tumor diameter was evaluated after 3 or 4 cycles, median 80 days after the first NAC (range, 63-86), and ranged from 16 to 100%.…”

“…Independent Component Analysis (ICA), as implemented in the tool MELODIC in the same software package, was used to remove residual effects of the motion correction algorithm and remove minor motion disturbance from the remaining DCE-MRI series. The algorithm decomposes the intensity-time curves from each series in a set of statistically independent components (13)(14)(15)(16)(17)(18)(19) for the data analyzed in this work, automatically selected by the algorithm as a trade-off between complexity and accuracy) under the assumption that the original data can be obtained as a linear combination of the components. ICA can separate components that are located within the tumor region and show the enhancement curve that is typical of breast carcinomas from other sources of signal (18).…”

DCE-MRI biomarkers in the clinical evaluation of antiangiogenic and vascular disrupting agents

“…Other related measures such as the rate constant (k ep ), which describes the ratio of K trans /v e have also been used. Several models have been applied to clinical trial data to enable calculation of K trans and v e , many of which are equivalent (Larsson et al, 1990;Tofts and Kermode, 1991).…”

DCE‐MRI pixel‐by‐pixel quantitative curve pattern analysis and its application to osteosarcoma

“…The methods for DCE-MRI data processing can be divided into three types: Heuristic models (9 -14), pharmacokinetic models (15)(16)(17)(18)(19), and pattern analysis (20,21). Within each type there is a variety of derived models.…”

“…Pharmacokinetic models are widely used in DCE-MRI (15)(16)(17)(18)(19). After converting the dynamic signal to the contrast agent concentration, several pharmacokinetic parameters can be assessed on the basis of pharmacokinetic modeling.…”