Delayed Contrast Extravasation MRI for Depicting Tumor and Non-Tumoral Tissues in Primary and Metastatic Brain Tumors

Abstract

The current standard of care for newly diagnosed glioblastoma multiforme (GBM) is resection followed by radiotherapy with concomitant and adjuvant temozolomide. Recent studies suggest that nearly half of the patients with early radiological deterioration post treatment do not suffer from tumor recurrence but from pseudoprogression. Similarly, a significant number of patients with brain metastases suffer from radiation necrosis following radiation treatments. Conventional MRI is currently unable to differentiate tumor progression from treatment-induced effects. The ability to clearly differentiate tumor from non-tumoral tissues is crucial for appropriate patient management. Ten patients with primary brain tumors and 10 patients with brain metastases were scanned by delayed contrast extravasation MRI prior to surgery. Enhancement subtraction maps calculated from high resolution MR images acquired up to 75 min after contrast administration were used for obtaining stereotactic biopsies. Histological assessment was then compared with the pre-surgical calculated maps. In addition, the application of our maps for prediction of progression was studied in a small cohort of 13 newly diagnosed GBM patients undergoing standard chemoradiation and followed up to 19.7 months post therapy. The maps showed two primary enhancement populations: the slow population where contrast clearance from the tissue was slower than contrast accumulation and the fast population where clearance was faster than accumulation. Comparison with histology confirmed the fast population to consist of morphologically active tumor and the slow population to consist of non-tumoral tissues. Our maps demonstrated significant correlation with perfusion-weighted MR data acquired simultaneously, although contradicting examples were shown. Preliminary results suggest that early changes in the fast volumes may serve as a predictor for time to progression. These preliminary results suggest that our high resolution MRI-based delayed enhancement subtraction maps may be applied for clear depiction of tumor and non-tumoral tissues in patients with primary brain tumors and patients with brain metastases.

Blood–Brain Barrier Imaging in Human Neuropathologies

“…However, as previously shown (66,67), short scans may miss information hidden in slower processes. The described work compares enhancement patterns using three time points following CA injection, with the last point at 75-min post-injection.…”

Blood‐brain barrier dysfunction in canine epileptic seizures detected by dynamic contrast‐enhanced magnetic resonance imaging

“…Dogs with encephalitis and dogs with IE displayed multifocal BBBD, whereas in dogs with tumors, the BBB was damaged primarily in and around the tumor. BBBD has often been reported around brain tumors . Using the linear DCE‐MEI added details that enabled identification of regions within and around the tumor with quick washout of the contrast (a negative slope), suggesting high density of blood vessels, as well as areas of mainly positive slope voxels, indicative of BBBD and representing the tumor bed.…”

Increase in FLAIR Signal of the Fluid Within the Resection Cavity as Early Recurrence Marker: Also Valid for Brain Metastases?

“…Another limitation might arise due to the sometimes quite difficult differentiation between tumor progression and pseudoprogression in brain metastases [28,31,32]. For gliomas, PET and perfusion imaging are important for differentiation.…”