Perivascular spaces and headache: A population-based imaging study (HUNT-MRI).

BACKGROUND: In four previous clinic-based MRI studies headache sufferers (in particular migraineurs) had more perivascular spaces (PVS) than individuals who were headache-free. METHODS: The present study was part of a large longitudinal, epidemiological study (Nord-Trøndelag Health Survey (HUNT)). The 1006 participants, age 50-65 years at inclusion, had participated in all previous HUNT surveys (1-3), and been randomly selected to a population-based imaging study of the head (HUNT-MRI, 2007-2009). The number of visible PVS in the basal ganglia (BG) and hemispheric white matter (HWM) was compared in headache sufferers (migraine with and without aura, non-migrainous headache) and people who were headache-free. RESULTS: The results showed in general small differences between headache sufferers and headache-free participants. In the cross-sectional analysis migraineurs without aura had fewer PVS than headache-free individuals in BG (OR = 0.84, 95% CI = 0.76--0.94, p value = 0.003) and in BG and HWM together (OR = 0.97, 95% CI = 0.95-1.00, p value = 0.046). No difference between long-term headache sufferers and long-term headache-free individuals with regard to number of PVS was found. DISCUSSION: In contrast to previous studies, the present large, blinded, population-based study showed no increase in number of dilated PVS among headache sufferers. Fewer PVS among those with migraine without aura may be a spurious finding.

Comparison of contrast in brightness mode and strain ultrasonography of glial brain tumours.

BACKGROUND: Image contrast between normal tissue and brain tumours may sometimes appear to be low in intraoperative ultrasound. Ultrasound imaging of strain is an image modality that has been recently explored for intraoperative imaging of the brain. This study aims to investigate differences in image contrast between ultrasound brightness mode (B-mode) images and ultrasound strain magnitude images of brain tumours. METHODS: Ultrasound radiofrequency (RF) data was acquired during surgery in 15 patients with glial tumours. The data were subsequently processed to provide strain magnitude images. The contrast in the B-mode images and the strain images was determined in assumed normal brain tissue and tumour tissue at selected regions of interest (ROI). Three measurements of contrast were done in the ultrasound data for each patient. The B-mode and strain contrasts measurements were compared using the paired samples t- test. RESULTS: The statistical analysis of a total of 45 measurements shows that the contrasts in the strain magnitude images are significantly higher than in the conventional ultrasound B-mode images (P < 0.0001). CONCLUSIONS: The results indicate that ultrasound strain imaging provides better discrimination between normal brain tissue and glial tumour tissue than conventional ultrasound B-mode imaging. Ultrasound imaging of tissue strain therefore holds the potential of becoming a valuable adjunct to conventional intraoperative ultrasound imaging in brain tumour surgery.