Brain Tumour MRI — Grading, Perfusion & Post-Treatment

Brain Tumour MRI

Conventional MRI finds and locates a brain tumour; advanced sequences help say how aggressive it is — and, after treatment, whether it’s coming back.

The conventional core

T1 pre/post-gadolinium, T2/FLAIR, and diffusion characterise a mass: enhancement pattern, oedema, mass effect, and restricted diffusion (highly cellular tumour, e.g. lymphoma). Enhancement reflects blood–brain barrier breakdown but does not by itself equal high grade.

Grading with advanced sequences

Perfusion (DSC/DCE): relative cerebral blood volume (rCBV) rises with angiogenesis — higher rCBV supports higher-grade glioma.
Spectroscopy: raised choline, reduced NAA (high Cho/NAA), lactate/lipid in aggressive/necrotic tumour.
Diffusion/ADC: low ADC reflects dense cellularity.

No single sequence grades a tumour — it’s the multiparametric picture, always confirmed by histology/molecular markers.

The hardest question: recurrence vs treatment effect

After chemoradiotherapy, new enhancement may be true progression or radiation necrosis / pseudoprogression. Perfusion (recurrent tumour tends to higher rCBV) and spectroscopy help distinguish them, and follow-up is assessed with structured criteria (RANO). This distinction directly changes management.

Reference: Wen PY et al. Response Assessment in Neuro-Oncology (RANO). J Clin Oncol; Boxerman JL et al. perfusion MRI consensus in glioma.

Educational summary for clinicians; diagnosis requires histology/molecular data. Not medical advice.