Transradial access for pediatric teenage neurointervention: A single-center case series.

Transradial access is widely used in cardiological adult interventions and less in pediatrics. In recent years, this access has become more popular in the neuroradiological community in adult patients since it has fewer complications and is more comfortable for the patient after the procedure. We present a single-center case series of 52 transradial access neurointerventions (43 angiographies and 9 therapeutic procedures) in pediatric patients, with a failure of 4 cases (7.7%) in which we could not puncture the artery, crossing over to transfemoral access. Since in five cases we did angiography followed by therapeutic intervention, thus doing only one puncture access for both procedures, then our access failure rate was 10.6%. The 34 successful transradial access solely angiographies had a median radiation exposure of 887 mGy (interquartile range 628-1352), median fluoroscopy time of 9.5 min (interquartile range 7.5-15.3), and median procedure time of 28 min (interquartile range 24-33 min) Therapeutic procedure diagnosis were: one ruptured saccular aneurysm, two juvenile nasopharyngeal angiofibromas, and five arteriovenous malformations. The transradial access neurointerventions for pediatric population older than 11 years is safe and feasible, having previous experience in adults. Younger population should be considered on a case-to-case basis, depending on ultrasound measurement of the arterial diameter and the materials available.

Impact of b-Value Sampling Scheme on Brain IVIM Parameter Estimation in Healthy Subjects.

PURPOSE: Intravoxel incoherent motion (IVIM) analysis has attracted the interest of the clinical community due to its close relationship with microperfusion. Nevertheless, there is no clear reference protocol for its implementation; one of the questions being which b-value distribution to use. This study aimed to stress the importance of the sampling scheme and to show that an optimized b-value distribution decreases the variance associated with IVIM parameters in the brain with respect to a regular distribution in healthy volunteers. METHODS: Ten volunteers were included in this study; images were acquired on a 1.5T MR scanner. Two distributions of 16 b-values were used: one considered 'regular' due to its close association with that used in other studies, and the other considered 'optimized' according to previous studies. IVIM parameters were adjusted according to the bi-exponential model, using two-step method. Analysis was undertaken in ROI defined using in the Automated Anatomical Labeling atlas, and parameters distributions were compared in a total of 832 ROI. RESULTS: Maps with fewer speckles were obtained with the 'optimized' distribution. Coefficients of variation did not change significantly for the estimation of the diffusion coefficient D but decreased by approximately 39% for the pseudo-diffusion coefficient estimation and by 21% for the perfusion fraction. Distributions of adjusted parameters were found significantly different in 50% of the cases for the perfusion fraction, in 80% of the cases for the pseudo-diffusion coefficient and 17% of the cases for the diffusion coefficient. Observations across brain areas show that the range of average values for IVIM parameters is smaller in the 'optimized' case. CONCLUSION: Using an optimized distribution, data are sampled in a way that the IVIM signal decay is better described and less variance is obtained in the fitted parameters. The increased precision gained could help to detect small variations in IVIM parameters.

Incidence of subarachnoid haemorrhage in the Aconcagua Valley, Chile: a community-based, prospective surveillance project.

BACKGROUND: An epidemiological surveillance project was set up in Central Chile to detect cases of subarachnoid haemorrhage (SAH) and its incidence. METHODS: Community-based prospective surveillance project carried out between 1 July 2000 and 30 June 2003, in the Aconcagua Valley in Central Chile. The authors ascertained all possible cases using multiple overlapping sources. Incidence rates were age-sex-adjusted. RESULTS: The authors identified 33 first-ever cases; 19 were women. The mean age (SD, range) was 50.7 (17.9, 16 to 82). The incidence per 100,000 age-sex adjusted to the world population was 5.1 (4.4 men, 5.6 women). The 30-day case-death rate was 54.5% (95% CI 38.0 to 70.2), and the prehospital death rate 21.2% (95% CI 10.7 to 37.7). CONCLUSIONS: The incidence rate in Aconcagua is notably similar to that reported previously in Northern Chile and lower than in many high-income western populations. The lower incidence rates found in these two Chilean populations might be due to their younger age. A trend towards a higher 30-day case-death rate found in Central Chile is possibly associated with its higher rurality and therefore lesser accessibility to preventive measures and medical care.