Enhancing brain tumor characterization with pCASL imaging

Medical history

A 55 year-old woman underwent an MRI after 2 months of a sensory-motor deficit of the right hemibody. Symptoms were progressive, predominant on the lower limb, and required a walking aid. Partial motor seizures also occurred, with spontaneous resolution within a few minutes.

Image acquisition and analysis

MR images were obtained using a 3T MRI scanner (Skyra, Siemens Healthineers, Erlangen, Germany). The protocol included 3D T2-weighted (T2w), Fluid-Attenuated Inversion Recovery (FLAIR) and T1-weighted acquisitions before (T1w) and after (T1wE) contrast injection, as well as Diffusion Weighted Imaging (DWI), Susceptibility Weighted Imaging (SWI), Dynamic Susceptibility Contrast (DSC) perfusion and Pseudo-Continuous Arterial Spin Labeling (pCASL) sequences.

DWI, DSC perfusion and pCASL data were post-processed with Olea Sphere 3.0 (Olea Medical, La Ciotat, France) to obtain Apparent Diffusion Coefficient (ADC), DSC relative Cerebral Blood Volume (rCBV) and pCASL relative Perfusion Weighted Imaging (rPWI) maps, respectively.

Findings

Conventional MRI sequences revealed a contrast-enhancing, necrotic, peri-rolandic left mass (Fig. 1).

SWI showed a high intra-tumoral susceptibility signal (ITSS) in the posterior and mesial side of the lesion (orange arrows), possibly partially influencing DWI signal and rCBV cartography derived from DSC perfusion (Fig. 2).

The 3D pCASL rPWI map was also markedly increased in this part of the lesion (Fig. 3).

pCASL imaging definitely confirmed the presence of neo-angiogenesis in the peri-rolandic left mass. Therefore, multimodal MRI suggested the presence of an aggressive brain tumor. Subsequent partial surgical resection and histo-molecular analysis allowed the diagnosis of glioblastoma, IDH-wildtype, WHO grade 4.

Conclusion

This case illustrates the benefit of adding pCASL perfusion in brain tumor characterization. While sus­ceptibility artefacts are commonly present in pre- and post-surgical brain lesions and often affect DSC perfusion interpretation, they do not impact pCASL analysis, hence increasing the clinical value of this contrast-free perfusion technique.