Background: Inhalational anesthetic-induced burst suppression (BS) is classically considered a bilaterally synchronous rhythm. However, local asynchrony has been predicted in theoretical studies and reported in patients with pre-existing focal pathology.Method: We used high-speed widefield calcium imaging to study the spatiotemporal dynamics of isoflurane-induced BS in rats.Results: We found that isoflurane-induced BS is not a globally synchronous rhythm. In the neocortex, neural activity first emerged in a spatially shifting, variably localized focus. Subsequent propagation across the whole cortex was rapid, typically within <100 milliseconds, giving the superficial resemblance to global synchrony. Neural activity remained locally asynchronous during the bursts, forming complex recurrent propagating waves. Despite propagation variability, spatial sequences of burst propagation were largely preserved between the hemispheres, and neural activity was highly correlated between the homotopic areas. The critical role of the thalamus in cortical burst initiation was demonstrated by using unilateral thalamic tetrodotoxin injection.Conclusion: The classical impression that anesthetics-induced BS is a state of global brain synchrony is inaccurate. Bursts are a series of shifting local cortical events facilitated by thalamic projection that unfold as rapid, bilaterally asynchronous propagating waves.

Background Hemangioblastomas are rare benign tumours that are most commonly detected in the subtentorium or spinal cord. Optic nerve hemangioblastoma is very rare and is most commonly associated with Von Hippel-Lindau (VHL) syndrome. Case presentation Here, we report a case of hemangioblastoma of the optic nerve with bilateral frontal lobe oedema without VHL syndrome, which has not yet been reported. A 51-year-old woman presented with progressive and painless deteriorating vision in the left eye. Magnetic resonance imaging showed a mass at the back of the left orbital optic nerve. Endoscopic-assisted intraorbital tumour resection was performed successfully. The pathological diagnosis was left optic nerve hemangioblastoma. Conclusions This is the first reported case of optic nerve hemangioblastoma (HBL) with bilateral frontal lobe oedema.

Objectives: In the present study, we introduced a practical approach to quantify organ-specific radiation doses and investigated whether low-dose head circumference (HC)-based protocols for non-enhanced head computed tomography (CT) could reduce organs-specific radiation dose in pediatric patients while maintaining high image quality. Methods: A total of 83 pediatric patients were prospectively recruited. Without limits to the HC, 15 patients were selected as a convention group (CON group) and underwent non-enhanced head CT scan with standard-dose protocols (tube current-time products of 250mAs). Low-dose group (LD group), including remaining 68 pediatrics were divided into 3 subgroups based on the HC: 54.1-57.0 cm for LD200mAs group (HC-based protocols of 200mAs), 51.1-54.0 cm for LD150mAs group (HC-based protocols of 150mAs), 48.1-51.0 cm for LD100mAs group (HC-based protocols of 100mAs). Subjective and objective image quality was evaluated and measured by 2 experienced radiologists. Radimetrics was used to calculate organs-specific radiation dose, including the brain, eye lenses, and salivary glands. Results: In CON250mAs group, radiation doses in the brain and salivary glands were conversely correlated with HC, and pediatric patients with smaller HC received higher organs-specific radiation dose. Reducing tube current-time product from 250 to 100mAs could significantly reduce the organ-specific radiation dose. The subjective image quality score ≥ 3.0 is acceptable for diagnosis purposes. The signal to noise ratio (SNR) and the contrast to noise ratio (CNR) of bilateral thalamus and centrum semiovale in 3 LD subgroups were not statistically different compared with the CON group. Conclusion: Our research indicated that low-dose HC-based protocols of non-enhanced head CT scan can evidently reduce the organ-specific radiation doses, while maintaining high image quality. HC can serve as a vital tool to guide personalized low-dose head CT scan for pediatric patients.

Background: Same head CT examination protocol was employed for pediatric patients who’s skull sizes are different , this could be excessive radiation doses because they usually have smaller head circumference. In our study, we investigate if mAs according to head circumference(HC) reduce radiation doses of sensitive organs including brain, eye lens and salivary glands, but could keep the image quality. Methods: 83 pediatric patients were prospectively selected. Without limiting the head circumference, 15 pediatrics were selected as conventional group by random number method and received routine head CT examination protocol (250mAs). Low-dose group including remaining 68 patients were divided into 3 subgroups based on HC: 54.1-57.0cm for group A(200mAs), 51.1-54.0cm for group B(150mAs), 48.1-51.0cm for group C(100mAs). The Image quality was assessed by subjective and objective image score. Radimetrics was used to calculate radiation doses of sensitive- organs. Results: In the conventional group, pediatric patients with smaller head circumference receive higher radiation doses of sensitive-organs. Radiation doses of brain and salivary glands were negatively correlated with HC. The radiation dose of sensitive-organs in 3 low-dose subgroups were significantly lower than conventional group. The subjective image quality scores in group A and B was no statistical different than conventional group. The SNR of thalamus and centrum ovale in low-dose subgroups were no statistical differences compared with conventional group. Conclusions: Our research indicates that personalized brain CT examination in pediatrics can reduce the radiation doses of sensitive-organs but keep image quality. HC can serve as an effective index to guide personalized head CT scan.