MRI - MRI 7 months post-surgery
Axial T1
Axial T1 C+
Axial FLAIR
Axial T2
Axial ADC
MRS
Axial MR Perfusion (CBV)
Axial DWI
Axial ADC
Axial Gradient Echo
Coronal T1 C+
Right frontal craniotomy. Underlying this is an enhancing mass with marked increase of surrounding FLAIR hyperintensity, which crosses the midline at the genu of the corpus callosum and extends to the posterior frontal lobe. There is effacement of the frontal horn of the right lateral ventricle with subfalcine herniation and leftward midline shift of 4.5 mm. No hydrocephalus.
Cerebral blood volume is reduced throughout the right frontal lobe without any areas of focal elevation. Specifically, the enhancing component of the mass does not demonstrate high rCBV.
Only a thin rim of diffusion restriction surrounds the resection cavity, smaller than the enhancing component, which mostly demonstrates facilitated diffusion.
MR spectroscopy in the enhancing component of the mass is dominated by lipid and lactate peaks on an otherwise hypometabolic baseline.
Conclusion
Marked increase in the enhancing mass and FLAIR signal. Although there are areas of low ADC, that are concerning for viable high-grade tumour, the low cerebral blood volume and lack of choline elevation, large lipid and lactate peaks on spectroscopy suggest the dominant process, especially in the context of an MGMT methylated tumour, 7 months post-surgery, favour pseudoprogression as being the dominant process.