Prognostic value of brain tissues' volumes in patients with essential tremor treated with MRgFUS thalamotomy.

MRgFUS Vim thalamotomy is a novel, effective, minimally invasive therapeutic option for patients with essential tremor (ET). Among the selection criteria, some parameters related to the patient's anatomy, such as the skull density ratio (SDR), are well recognized. The role of brain tissue interposed between the target and the ultrasound transducers has never been explored. Therefore, the purpose of our study was to evaluate the correlation and the possible predictive value between brain tissue volumes (grey matter - GM, white matter - WM, and cerebrospinal fluid - CSF) and several treatment-related variables (periprocedural parameters, MRI imaging findings, and the clinical outcome). We analysed data from thirty ET patients previously submitted to MRgFUS thalamotomy. Pre-treatment images were automatically segmented in sopra-tentorial (ST) WM, GM, and CSF using SPM 12. The most significant findings were a positive correlation of the ST-GM with the Accumulated Thermal Dose (ATD) (p < 0,001) and a negative correlation of the ATD temperature with ST-CSF and ST-TIV (p < 0,001). Ultrasound propagation speed is lower in fluids than brain tissues. Also, WM has an attenuation rate of 1.5 higher than the GM. Therefore, the difference in the ATD may be explained by the different acoustic properties of normal brain tissues interposed between the transducers and the VIM.

A population-based study of the incidence and prognosis of lacunar stroke.

OBJECTIVE: To evaluate incidence and prognosis of lacunar stroke in a prospective, population-based patient registry. METHODS: The authors included first-ever strokes occurring between 1994 and 1998. They assessed incidence, risk factors, mortality, and recurrence in patients with lacunar stroke. RESULTS: The authors identified 491 patients (15.3%) with lacunar stroke (252 men and 239 women) and 2,153 patients (67.3%) with nonlacunar stroke (998 men and 1,155 women). Crude annual incidence rate for a first-ever lacunar stroke was 33.0/100,000 (95% CI 30.2 to 36.0). At the univariate logistic regression analysis among patients with lacunar stroke there was a higher proportion of cigarette smoking and hypercholesterolemia and a lower proportion of chronic atrial fibrillation than in patients with nonlacunar stroke. For lacunar stroke, the 30-day case-fatality rate was 4.3% (95% CI 2.5 to 6.1) and the 1-year case-fatality rate was 13.0% (95% CI 10.0 to 16.0). During the first year of follow-up the average annual stroke recurrence rate was lower in patients with lacunar (2.83%; 95% CI 1.36 to 4.30) than in those with nonlacunar stroke (5.10%; 95% CI 4.17 to 6.03) while from the second year onward, rates were similar in both groups. CONCLUSION: In the short term, patients with nonlacunar stroke had more vascular events, but in the long term, the risk of death and of stroke recurrence was similar.