RESUMO
OBJECTIVE: a considerable subgroup of meningiomas (MN) exhibit indolent and insidious growth. Strategies to detect earlier treatment responses based on tumour biology rather than on size can be useful. We aimed to characterize therapy-induced changes in the apparent diffusion coefficient (ADC) of MN treated with proton-therapy (PT), determining whether the pre- and early post-treatment ADC values may predict tumour response. METHODS: Forty-four subjects with MN treated with PT were retrospectively enrolled. All patients underwent conventional magnetic resonance imaging (MRI) including diffusion-weighted imaging (DWI) at baseline and each 3 months for a follow-up period up to 36 months after the beginning of PT. Mean relative ADC (rADCm) values of 46 MN were measured at each exam. The volume variation percentage (VV) for each MN was calculated. The Wilcoxon test was used to assess the differences in rADCm values between pre-treatment and post-treatment exams. Patients were grouped in terms of VV (threshold -20%). A p < 0.05 was considered statistically significant for all the tests. RESULTS: A significant progressive increase of rADCm values was detected at each time point when compared to baseline rADCm (p < 0.05). Subjects that showed higher pre-treatment rADCm values had no significant volume changes or showed volume increase, while subjects that showed a VV < -20% had significantly lower pre-treatment rADCm values. Higher and earlier rADCm increases (3 months) are related to greater volume reduction. CONCLUSION: In MN treated with PT, pre-treatment rADCm values and longitudinal rADCm changes may predict treatment response.
RESUMO
Mild encephalopathy with a reversible splenial lesion (MERS) is a clinico-radiological syndrome characterized by a transient mild encephalopathy and MRI findings of a reversible lesion in the splenium of corpus callosum (SCC). It is classified in MERS type I and MERS type II, depending on the involvement of SCC alone or also other white matter areas. The syndrome mainly affects children and young adults; the prognosis is favorable with complete or nearly complete neurological and radiological resolution within days or weeks. The vast majority of the cases described in the literature involve Asian and Australian children. The exact pathophysiology is unknown; however, infectious-related MERS (in particular virus associated MERS) remains the most common cause of reversible splenial lesions in childhood. To the best of our knowledge, there is only one published case of MERS associated with cytomegalovirus (CMV) infection involving an Australian child. We present here the first case of a CMV-related MERS in a European Caucasian child.
