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PSEUDO-RESPONSE:
Angiogenetic inhibitors can cause a decrease in contrast
enhancement due to reduction in blood-brain barrier permeability rather then true
reduction in volume
(
Clarke JL et al. Curr Neurol Neurosci Rep 2009).
Pseudo-response might be an indicator of subsequent favourable response
A 47-year-old man with GBM. A reduction of the enhancing portion of the lesion is observed 1 day after initiation of cediranib
treatment. Four weeks later, besides a continuing reduction in the enhancing portion, an expansion is observed in the FLAIR
images. Expansions in both the enhancing area and abnormal hyperintense areas consistent with tumor progression were
observed subsequently (L.C. Hygino da Cruz Jr et al. AJNR 2011)
IMAGING of TREATMENT RESPONSE
PSEUDO-RESPONSE
RANO Criteria for pseudoresponse: greater than 50%
reduction in contrast enhancement without a significant
decrease in nonenhancing tumour.
Decreased enhancement should persist more than 4
weeks to be considered true response.