Early-onset symptomatic radiation necrosis after stereotactic radiosurgery in the setting of COVID-19 infection.

In this brief report, we describe the case of a previously healthy 51-year gentleman who was treated with stereotactic radiosurgery to a dose of 12 Gy to a small right-sided vestibular schwannoma. MRI of the brain performed after treatment revealed stable treated disease but subsequently, the patient developed symptomatic COVID-19 based on PCR along with multiple cranial neurologic deficits, including right facial paralysis, hemifacial anesthesia, and anesthesia of the ipsilateral hard palate and tongue. MRI of the brain was repeated and demonstrated radiation necrosis in the adjacent brainstem for which he was treated with Pentoxifylline and Vitamin E, dexamethasone, and Bevacizumab with only partial improvement. The dose-volume metrics of the brainstem from his radiotherapy plan as well as the trajectory of his imaging findings do not match this clinical picture from radiotherapy alone. We review the basic pathogenesis of the inflammatory response to infection from the SARS-CoV-2 virus as well as the pathogenesis of radiation necrosis. Heightened awareness about potential risks with high-dose radiotherapy in patients with symptomatic COVID-19 should be considered.

Estimating the Risks of Adverse Radiation Effects After Gamma Knife Radiosurgery for Arteriovenous Malformations.

BACKGROUND AND PURPOSE: We evaluated risk factors associated with the development of adverse radiation effects (ARE) after stereotactic radiosurgery (SRS) for cerebral arteriovenous malformations (AVMs). METHODS: We evaluated 755 patients with AVM who underwent a single Gamma Knife SRS procedure with at least a 2-year minimum follow-up. Eighty-seven patients (12%) underwent previous resection and 128 (17%) had previous embolization. The median target volume was 3.6 mL (range, 0.1-26.3 mL). The median margin dose was 20 Gy (range, 13-27 Gy). RESULTS: Fifty-five patients (7%) developed symptomatic ARE at a median follow-up of 75 months. The cumulative rates of symptomatic ARE were 3.2%, 5.8%, 6.7%, and 7.5% at 1, 2, 3, and 5 years, respectively. Factors associated with a higher rate of developing symptomatic ARE included larger AVM volume, higher margin dose, larger 12-Gy volume, higher Spetzler-Martin grade, and higher radiosurgery-based score. The rates of developing symptomatic ARE were higher in the brain stem (22%) or thalamus (16%), compared with AVMs located in other brain locations (4%-8%). Nineteen patients (3%) sustained irreversible new neurological deficits related to ARE, and 1 patient died. The rates of irreversible symptomatic ARE were 0.8%, 1.9%, 2.1%, and 2.8% at 1, 2, 3, and 5 years, respectively. The 5-year cumulative rates of irreversible symptomatic ARE were 9.1% in thalamus, 12.1% in brain stem, and 1.4% in other locations. CONCLUSIONS: The knowledge of ARE risk rates after AVM radiosurgery can assist informed consent for patients with AVM, their families, and healthcare providers.

Radionecrosis versus disease progression in brain metastasis. Value of (18)F-DOPA PET/CT/MRI. / Radionecrosis versus progresión de la enfermedad en metástasis cerebrales: valor del (18)F-DOPA PET/TC/RM.

The use of (18)F-DOPA PET/CT with magnetic resonance imaging fusion and the use of visual methods and quantitative analysis helps to differentiate between changes post-radiosurgery vs. suspicion of disease progression in a patient with brain metastases from melanoma, thus facilitating taking early surgical action.