Glioma perfusion quantification with ASL and DSC: head-to-head comparison with 15O-H₂O PET

Ziel/Aim Arterial spin labeling (ASL) MRI is a method to measure cerebral blood flow (CBF) that uses magnetically labeled blood. So far, its quantitative accuracy and reproducibility with respect to the gold standard of 15O-H₂O PET has been assessed in healthy volunteers and different diseases [1] but not yet in brain tumors. Here, we compare preoperative ASL, PET, and DSC scans side-by-side in eight patients with diffuse glioma.

Methodik/Methods Eight adult patients – 5 men, 3 women, age 40.5±17.0 years – suspected of a newly diagnosed, untreated, diffuse supratentorial cerebral glioma were included [2]. MR imaging – T1-weighted, pseudo-continuous ASL (PCASL), and dynamic susceptibility contrast (DSC) – was performed with a 3T Achieva Philips scanner. Dynamic whole-brain 15O-H2O PET scans were acquired on a Gemini time-of-flight PET-CT scanner including arterial blood sampling [3].

Ergebnisse/Results The linear correlation between ASL and PET predictor function for CBF was: PET=0.995*ASL (CI 0.893 – 1.097) in the healthy tissue. In tumor, cortical BF normalized to contralateral side was PET=1.08*ASL (0.77-1.38) and PET=1.03*DSC (0.74-1.32), with relative difference in tumor BF compared with PET of 21% for ASL and 23.5% in DSC. Qualitative assessment revealed regional discrepancies occurring for, both, ASL and DSC modalities.

Schlussfolgerungen/Conclusions Compared with PET, perfusion imaging with ASL and DSC proved to be challenging in tumors with significant vascular changes, such as a disrupted BBB or a high degree of neovascularization — ASL overestimated BF in the presence of intravascular signal, and DSC underestimated perfusion in non-enhancing tumors. While neither ASL nor DSC can replace PET in tumor quantitative perfusion measurement, ASL is a viable non-invasive semi-quantitative alternative to DSC because of a sensitivity comparable to PET. Moreover, ASL can present complementary information to DSC and thus warrants further research in its utility for glioma assessment.

Publication History

Article published online:
14 April 2022

• Literatur/References

• 1 Fan et al. JCBFM. 2016
• 2 Verburg et al. Neurosurgery. 2016
• 3 Verburg et al. Neuro-Oncology. 2020