Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a perfusion technique that allows a non-invasive characterization of the vascular microenvironment through quantitative estimates of vascular permeability parameters [1,2]. DCE-MRI has the potential to assess the blood-brain barrier (BBB) integrity, through the extraction of several features that can help to differentiate brain lesions [[3], [4], [5], [6], [7], [8]]. DCE-MRI has shown promising results for tissue characterization, prediction, and monitoring treatment response in brain lesions [4].

Through the pharmacokinetic model of Tofts et al. [9], it is possible to calculate DCE-MRI-derived kinetic parameters that reflect the two-compartment pharmacokinetics exhibited by paramagnetic contrast agents, which are distributed between the intravascular and extravascular spaces [10]: volume of extravascular extracellular space (EES) per unit volume of tissue (Ve), volume transfer constant between blood plasma and EES (Ktrans), the rate constant between the EES and blood plasma (Kep), and the initial area under the gadolinium curve (IAUGC) [11]. Ktrans is a measure of capillary permeability and is considered to reflect neoangiogenesis. Ve is an independent kinetic parameter that appears in the Tofts model [9]: it is the fractional volume of the EES. It is formally defined as the volume of the EES per unit volume of tissue and consists of a dimensionless number between 0 and 1. The Ve parameter reflects the amount of “space” available within the tissue interstitium where gadolinium accumulates and has been considered as an index of tumor necrosis and an inverse index of tumor cellularity [12]. The DCE parameters are influenced by several factors: acquisition parameters, magnetic field strength of scanners, total acquisition scan time, type of contrast medium, modality of pre- and post-processing of data, motion correction and signal to concentration conversion [13].

The guidelines of the Radiological Society of North America's Quantitative Imaging Biomarkers Alliance (QIBA) emphasise the need to standardise acquisition parameters to reduce sources of variability in DCE imaging [14].

One of the least discussed questions about DCE examinations, related to the accuracy and reliability of the parameters, concerns the scan duration, which remains a parameter not fully considered. Most institutes perform DCE-MRI examination with acquisition protocols ranging from 3 to 7 min not considering that some parameters could be time-dependent, and these time ranges could be too short leading to underestimation of the values [15]. Regarding Ve, acquiring data with timings shorter than 10 min may not allow the gadolinium tracer to distribute properly between the EES and the vascular space and reach equilibrium, which may result in an inaccurate estimate [15]. However, in most institutions, the standard brain tumor protocol uses DCE-MRI scan times of 5 min.

The influence of acquisition time on the parameters extracted from the DCE-MRI examination has been evaluated mainly for breast and prostate tumors; meanwhile studies regarding the brain are inconsistent, and the duration of examinations does not exceed 7 min [[16], [17], [18]].

The purpose of this study is to evaluate the variation of the DCE-MRI parameters as a function of acquisition time from 5 to 10 min in different types of brain tumors.