Imagerie neurologique Solution APT CEST V.1.0

• IRM

A 56-year-old woman with a single brain metastasis of a HER2-positive breast cancer was treated with complete resection and Gamma Knife (GK) stereotactic radiotherapy of the surgical cavity. Three months after the GK procedure the patient was admitted to the hospital for seizures.

Multiparametric MRI in brain tumours is an invaluable methodology for obtaining in-depth information for the structural and functional tissue features guiding the differential diagnosis and assisting the tumour staging. Each MRI parametric maps provides crucial information for the different histomolecular tumour substrates, whereas the ‘tier-like’ interpretation of the combined structural-functional outputs helps the radiologist to reach an accurate diagnosis.

This case report shows the potential added value of Amide Proton Transfer (APT) contrast in the discrimination between radio-induced toxicity lesions and tumor progression in brain metastatic disease.

The young patient presented a first hyperthermic convulsive seizure. One month later, he presented another tonic-clonic episode with left hemicorporeal seizure lasting less than 5 minutes. Another month later, he had a tonic-clonic seizure again, without fever but complicated by status epilepticus. Afterwards, a CT scan showed a right parietal lesion, and he was transferred to the Necker- Enfants Malades hospital for a brain and spinal-cord MRI. The spinal-cord MRI did not reveal any metastases.