Localised increase in regional cerebral perfusion in patients with visual snow syndrome: a pseudo-continuous arterial spin labelling study

• Published in: Journal of neurology, neurosurgery and psychiatry Vol. 92; no. 9; pp. 918 - 926
• Main Authors: Puledda, Francesca, Schankin, Christoph J, O'Daly, Owen, Ffytche, Dominic, Eren, Ozan, Karsan, Nazia, Williams, Steve C R, Zelaya, Fernando, Goadsby, Peter J
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group LTD 01.09.2021; BMJ Publishing Group
• Series: Original research
• Subjects: Adult; Brain - diagnostic imaging; Brain research; Cerebrovascular Circulation - physiology; Female; Humans; Labeling; Magnetic Resonance Imaging; Male; Menstruation; Migraine; Migraine Disorders - diagnostic imaging; Neurosciences; Patients; Perceptual Disorders - diagnostic imaging; Perfusion Imaging; Spin Labels; Young Adult
• ISSN: 0022-3050; 1468-330X; 1468-330X
• DOI: 10.1136/jnnp-2020-325881

ObjectivesWe aimed to investigate changes in regional cerebral blood flow (rCBF) using arterial spin labelling (ASL) in patients with visual snow syndrome (VSS), in order to understand more about the underlying neurobiology of the condition, which remains mostly unknown.MethodsWe performed an MRI study in which whole-brain maps of rCBF were obtained using pseudo-continuous ASL. Twenty-four patients with VSS and an equal number of gender and age-matched healthy volunteers took part in the study. All subjects were examined with both a visual paradigm consisting of a visual-snow like stimulus, simulating key features of the snow, and a blank screen at rest, randomly presented.ResultsPatients with VSS had higher rCBF than controls over an extensive brain network, including the bilateral cuneus, precuneus, supplementary motor cortex, premotor cortex and posterior cingulate cortex, as well as the left primary auditory cortex, fusiform gyrus and cerebellum. These areas were largely analogous comparing patients either at rest, or when looking at a ‘snow-like’ visual stimulus. This widespread, similar pattern of perfusion differences in either condition suggests a neurophysiological signature of visual snow. Furthermore, right insula rCBF was increased in VSS subjects compared with controls during visual stimulation, reflecting a greater task-related change and suggesting a difference in interoceptive processing with constant perception of altered visual input.ConclusionThe data suggest VSS patients have marked differences in brain processing of visual stimuli, validating its neurobiological basis.