A comparison of measurement methods of hippocampal atrophy rate for predicting Alzheimer's dementia in the Aberdeen Birth Cohort of 1936.

INTRODUCTION: Various methods are available to measure hippocampal atrophy rate. We compared methods to predict Alzheimer's dementia. METHODS: Participants with brain imaging at ages 69 and 73 years were identified from a previous study. Simple manual measures and computationally automated volumetry were performed. Receiver operating characteristics assessed the predictive ability of each method at baseline and on logit regression analysis of two serial scans. RESULTS: Ten of 149 participants developed Alzheimer's dementia and had lower baseline volumes (3647 vs. 4194 mm3P = .002), rates of volume loss (-126 vs. -36 mm3/y; P = .001), and rates of loss in hippocampal fraction (-8.55 vs. -2.35 x 10-5/y; P = .001). Baseline volume with a rate of change gave the highest area under the curve value of 0.96. DISCUSSION: Automated volumetry measuring hippocampal size at age 69 years and subsequent rate of change predicts Alzheimer's dementia development.

Coil embolization of ruptured middle cerebral artery aneurysms in the first 2 months of life. Report of two cases.

Intracranial artery aneurysms are very rare in infants. There have been no previous reports of coil embolization to branches of the middle cerebral artery (MCA) in infants. The authors describe successful embolization of ruptured aneurysms of the right frontoopercular MCA branch in a 31-day-old infant, and of the left sylvian MCA branch in a 54-day-old infant. One of the cases involves a dissection flap. The authors also review cases in which coil embolization was used for intracranial aneurysms in the first 2 months of life.

Apparent diffusion coefficient (ADC) measurements may be more reliable and reproducible than lesion volume on diffusion-weighted images from patients with acute ischaemic stroke-implications for study design.

Early ischemic change after stroke can be demonstrated with diffusion-weighted imaging (DWI) and quantified by measuring the apparent diffusion coefficient (ADC) and/or lesion volume. We examined the reliability and reproducibility of lesion volume and ADC measurement on DWI images, and discuss the implications for clinical studies. Using 38 DWI scans from 15 stroke patients, two observers (a physicist and a neuroscience graduate) blind to each other, recorded the lesion volume on DWI sequences, measured the ADC values in this volume and calculated the ratio of ischemic: control ADC (ADCr). One observer repeated his measurements blind to his first, and also examined the effect on lesion volume and ADC of deliberately varying by only one pixel, the outline of the visible boundary of the lesion. The inter and intra-rater reliability were worse for lesion volume than ADC or ADCr measurements: lesion volume, inter-rater coefficient of variation (CoV) 85 +/- 130%, intra-rater CoV 20+/-SD80% (p < 0.05); ADC inter-rater CoV 7.7 +/- SD 19%, intra-rater CoV 0.2 +/- SD 12% (p = NS); and ADCr inter-rater CoV 8 +/- SD27%, intra-rater CoV 0.8 +/- SD73% (p = NS). Altering the position of the outline tracing of the lesion boundary by one pixel altered the measured volumes by 22 +/- SD25% (p < 0.05), but ADC values were altered by only 2.9 +/- SD4.9% and ADCr by 2.7 +/- SD4.8% (p = NS). ADC and ADCr values are more reliable and reproducible than DWI lesion size in acute ischemic stroke because altering where the lesion boundary is measured has a much greater impact on lesion volume than on the ADC or ADCr. This effect is greatest in large lesions.