High- and low-grade glioma differentiation: the role of percentage signal recovery evaluation in MR dynamic susceptibility contrast imaging.

PURPOSE: Evaluation of cerebral blood volume (CBV) with magnetic resonance (MR) imaging can differentiate low-grade from high-grade gliomas. The percentage of signal recovery (PSR) in the venous phase of perfusion curves is inversely proportional to blood-brain barrier (BBB) permeability. Since even BBB permeability relates to glioma malignancy grade, we carried out a comparative evaluation between CBV and PSR to characterise cerebral gliomas. MATERIALS AND METHODS: Forty-nine patients with cerebral gliomas were studied with MR perfusion imaging. In all tumours, both maximum CBV and minimum PSR were calculated. The difference between the CBV and PSR mean values among the low-grade and high-grade gliomas was assessed using statistical methods. We also examined whether there was an additional difference between low-grade and grade III gliomas. Finally, CBV and PSR diagnostic sensitivity and specificity in identifying low-grade gliomas compared to all gliomas and low-grade gliomas compared to all gliomas excluding glioblastomas was assessed. RESULTS: A significant difference between low-grade and high-grade gliomas with both CBV and PSR was demonstrated. Conversely, there was a significant difference between low-grade and grade III gliomas only with PSR, while CBV did not show significant difference. Finally, superior sensitivity and specificity of PSR compared to CBV in identifying low-grade gliomas was demonstrated both compared to all gliomas and all gliomas excluding glioblastomas. CONCLUSION: The PSR evaluation proved better than CBV for determining the grade of brain and is therefore a useful tool to be considered in the MR evaluation of gliomas.

The relationship between infratentorial lesions, balance deficit and accidental falls in multiple sclerosis.

OBJECTIVE: The role of static posturography and magnetic resonance imaging (MRI) in identifying patients at high risk of falls was investigated. Relationships between static posturography measures and MRI metrics were also investigated. METHODS: A total of 31 ambulatory MS patients (EDSS ranging from 2.0 to 5.0) with a predominant balance disorder were recruited. Each patient underwent a static posturography with a monoaxial platform and a conventional 1.5 T brain MRI scan. Measurements of T1-hypointense and T2-hyperintense lesion volumes (LVs), focusing on lesions selectively located at infratentorial levels, were performed by two operators unaware of clinical data. The self-reported number of falls in the previous 6 months was considered as the main outcome measure. RESULTS: Fourteen (45%) patients reported 1 or more falls over the past 6 months. When compared to non-faller patients, they had a higher EDSS score, poorer static standing balance, and greater brainstem and middle cerebellar peduncle (MCP) T2-LVs. A strength correlation between brainstem T2-LV and impaired static standing balance in an open eye condition was also found. In the multivariate analysis, the variables more strictly associated with recurrent falls were greater T2-LV at the MCP (beta: 6.2; p=0.01) and brainstem (beta: 5.8; p=0.001) levels, and a wider displacement of the body center of pressure in the closed eye condition (beta: 0.02; p=0.03). CONCLUSION: Our data suggests that the damage of specific infratentorial areas negatively affect the static standing balance and may predispose MS patients to accidental falls. These findings might contribute in selecting patients requiring a proper rehabilitation intervention program.