Improved 3D quantitative mapping of blood volume and endothelial permeability in brain tumors

Abstract

We describe a new method to allow simultaneous mapping of endothelial permeability and blood volume in intracranial lesions. The technique is based on a tumor leakage profile during the first pass (fp) of contrast bolus calculated from the time-dependent plasma-contrast concentration function (PCCF) in three-dimensional (3D) T1-weighted dynamic studies. The performance of the method has been evaluated by comparing results with those obtained from more conventional methods in patients with primary brain neoplasms. The new permeability maps (k fp ) are visually compatible with those calculated using a conventional multicompartment model (k tran ). Quantitatively, the new maps are free from overestimation of k tran due to first-pass effects. The new blood volume maps, which segment out the contamination of contrast leakage, agree closely with maps derived from susceptibility studies. The new method is fast, robust, and easy to perform. The method is suitable for use in clinical environments and is likely to be of benefit where longitudinal assessment of treatment response is required.

Comparative study into the robustness of compartmental modeling and model‐free analysis in DCE‐MRI studies

“…These strategies allowed rapid volume acquisition, suitable for DCE-MRI studies. Native tissue T 1 values were determined prior to contrast agent administration from three acquisitions with three different flip angles (␣ ϭ 2°, 10°, 35°) (14,15). The dynamic series utilized the same three-dimensional acquisition (TR, TE, FOV, matrix identical), with ␣ ϭ 35°, repeated to cover between three and six minutes.…”

“…The temporal resolution of the acquisition was approximately eight seconds, and images were acquired contiguously in time. Scanner transmitter and receiver gains were kept constant throughout both the baseline T 1 calculation and the dynamic series to facilitate signal comparisons for determination of contrast agent concentration (15,16). Contrast agent (0.1 mmol/kg of gadodiamide: Gd-DTPA-BMA [Omniscan, Nycomed, Norway]) was administered manually by an experienced neuroradiologist following the seventh dynamic scan.…”

“…For the second series, 6 volumes were acquired at 75-second intervals. Scanner transmitter and receiver gains were kept constant throughout both the baseline T 1 calculation and the two dynamic series to facilitate signal comparisons for determination of contrast agent concentration (0.1 mmol/kg gadopentate dimeglumine: Gd-DTPA [Magnevist, Schering, Germany]) (15,16).…”

Uncertainty in the analysis of tracer kinetics using dynamic contrast‐enhanced T1‐weighted MRI

“…As a practical example of these choices, the models were each fitted to recent experimental data (input and tissue residue curves) acquired in a meningioma (12), shown in Fig. 4.…”

“…Given this, the following analyses assume that the arterial input function has been measured. Although techniques to achieve this are not yet in common use, an increasing number of investigators are developing practical methods for doing so (11,12). …”