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Radiation necrosis

Contributedby:Dr.G.BhanuPrakash

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Radiation necrosis often enters into the differential diagnosis of an expanding brain lesion following therapy. The diagnosis is established by the presence of necrosis, thickened blood vessels and an infiltrate of macrophages. Cytologic atypia is unusual in the associated glia, although the endothelial cells may demonstrate atypia. Either smears or immunohistochemistry will reveal the macrophage population.

Tags: Dr.G.Bhanu, Prakash, gims, mci, plab, screening, test, usmle.mbbs

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Permalink Reply by Dr. Padmesh Jain on January 23, 2013 at 3:47pm

This is histopath diagnosis & an invasive method to differentiate radiation necrosis frm brain tumour. Once the patient is undergoing therapy this is not an advisable method due to obvious reasons.

MRS (Magnetic Resonance Spectroscpy) helps to solve the very important issue of differentiation of radiation necrosis and gliosis frm residual or recurrent neoplasm.

Patient with radiation necrosis will have reduced peaks of all metabolites whereas recurrent/residual tumour will have characteristic spectrum of tumour with elevated choline.

one can also take help of MR perfusion imaging for the same. A tumour will be hypervascular whereas radiation necrosis will be hypovascular

will post the image for the same in sometime

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Permalink Reply by Dr. Padmesh Jain on January 23, 2013 at 4:20pm

this is MRI-coronal image showing tumour in the right parietal region and the increase choline ratio in the spectrum along with bifid inverted lactate peak

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Permalink Reply by Dr. Padmesh Jain on January 23, 2013 at 4:23pm

this is an axial MRI of brain showing post-radiation tumour in the left temporal lobe. On perfusion image, the corresponding area shows more of red colour indicating hypervascularity suggesting recurrence.

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Permalink Reply by Dr. Padmesh Jain on January 23, 2013 at 4:31pm

Now, this sagittal MRI of brain shows post radiation tumour in the left frontal lobe. On perfusion image (2nd image), the corresponding area shows LESS of red colour indicating HYPOvascularity suggesting radiation necrosis.

On MR spectroscopy (last image)same area shows lots of noise and no dominant peak.

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Permalink Reply by Dindukurthi Sudhakar on January 23, 2013 at 4:38pm

Thanxalot for the very clear explanatory images and the notes, Dr.Padmesh Jain.

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Permalink Reply by James Lobo on January 24, 2013 at 12:26am

wow..Dr. Padmesh Jain.

thanx 4 such nice explanation with images.

i wasnt aware dat imaging hs so advanced dat v cn non-invasively determine so many things.

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Permalink Reply by Dr. Padmesh Jain on January 24, 2013 at 2:32pm

thanks Dindukurthi Sir and James.

@james..yes there has been tremendous advancement in the imaging modlities and nowadays with help of imaging features we can in some cases with 90 % accuracy predict the histological type as well..isnt that amazing ?