[Visualization of Cerebrospinal Fluid Dynamics by Respiratory Motion Using Phase Dispersion: Optimization of Spatial and Temporal Resolutions].

PURPOSE: The purpose of this study was to investigate the optimal spatial resolution and temporal resolution of dynamic improved motion-sensitized driven-equilibrium steady-state free precession for visualization of respiratory-driven cerebrospinal fluid (CSF) dynamics. METHODS: We investigated the differences in the visualization using the midsagittal cross-sections of nine healthy volunteers by three imaging conditions. (A: spatial resolution 0.49×0.49×5 mm, temporal resolution 1000 ms; B: 0.49×0.49×5 mm, 430 ms; and C: 0.78×0.78×5 mm, 200 ms). First, we calculated the CSF of the third and fourth ventricles and the signal-to-noise ratio (SNR) of the pons. Next, we calculated the signal intensity ratio (SIR) of the CSF flowing at 10 cm/s or more and the CSF flowing at 10 cm/s or less due to respiration. We also calculated the difference between the inspiration and expiration SIR. Furthermore, 1) the presence of flow in the third and fourth ventricles centered on the cerebral aqueduct and 2) the change in flow due to respiration was investigated by a three-point scale visual assessment by seven radiological technologists. RESULTS: The SNR was the highest in A, the next highest in B, and the lowest in C in all cases. There were significant differences between A and B, and A and C in CSF of the third and fourth ventricles. However, there was no significant difference between B and C. The CSF signal intensity changed with respiration. The SIR of the third ventricle was higher on inspiration and lower on expiration. Conversely, the SIR of the fourth ventricle was lower on inspiration and higher on expiration. There was a significant difference between A and C and B and C in each SIR (p<0.05). The difference between inspiration and expiration SIR was the highest in B, the next highest in A, and the lowest in C in both the third and fourth ventricles. Significant differences were found between A and C, and between B and C (p<0.05). There was no significant difference in the presence of flow in the third and fourth ventricles centered on the cerebral aqueduct (p=0.264). On the other hand, there was a significant difference between the imaging conditions in the change in flow due to respiration, with B having a higher value than the others (p<0.001). CONCLUSION: The optimal spatial and temporal resolutions were 0.49×0.49×5 mm and 430 ms, respectively. The results also suggest that it is important to carefully set the imaging conditions for the spatial and temporal resolutions because of the use of phase dispersion in this method.

Respiratory-driven Cyclic Cerebrospinal Fluid Motion in the Intracranial Cavity on Magnetic Resonance Imaging: Insights into the Pathophysiology of Neurofluid Dysfunction.

Neurofluids, a recently developed term that refers to interstitial fluids in the parenchyma and cerebrospinal fluid (CSF) in the ventricle and subarachnoid space, play a role in draining waste products from the brain. Neurofluids have been implicated in pathological conditions such as Alzheimer's disease and normal pressure hydrocephalus. Given that CSF moves faster in the CSF cavity than in the brain parenchyma, CSF motion can be detected by magnetic resonance imaging. CSF motion is synchronized to the heartbeat and respiratory cycle, but respiratory cycle-induced CSF motion has yet to be investigated in detail. Therefore, we analyzed CSF motion using dynamic improved motion-sensitized driven-equilibrium steady-state free precession-based analysis. We analyzed CSF motion linked to the respiratory cycle in four women and six men volunteers aged 23 to 38 years. We identified differences between free respiration and tasked respiratory cycle-associated CSF motion in the ventricles and subarachnoid space. Our results indicate that semi-quantitative analysis can be performed using the cranial site at which CSF motion is most prominent as a standard. Our findings may serve as a reference for elucidating the pathophysiology of diseases caused by abnormalities in neurofluids.

A Case of Endovascular Treatment for In-Hospital Stroke with COVID-19 under Protected Code Stroke.

Objective: Coronavirus disease 2019 (COVID-19) is characterized by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and presents with respiratory symptoms. Overall, 5.7% of COVID-19 patients with severe respiratory status have been reported to develop acute cerebrovascular diseases (CVDs), and 41.3% of COVID-19 cases were considered nosocomial infections. Therefore, Protected Code Stroke, which is a guideline for acute stroke management that takes into account the safety of healthcare workers, has been developed. We created an operational manual for COVID-19 in the endovascular treatment center of our hospital and report our experience treating acute stroke in a COVID-19 patient. Case Presentation: A 67-year-old man presented with a 5-day history of fever. Chest CT showed ground glass opacity (GGO) on admission, and the polymerase chain reaction (PCR) test for COVID-19 was positive. Dysarthria, right-sided hemiparesis, and aphasia were discovered on the morning of the third day after hospitalization. MRI showed an acute ischemic stroke at the left corona radiata and occlusion of the left middle cerebral artery (MCA). Progression of right-sided hemiparesis and exacerbation of respiratory status developed after the MRI. Tracheal intubation was performed, and the patient was treated with intravenous alteplase and mechanical thrombectomy (MT). Recanalization of blood flow was not obtained, and the neurological deficits remained. Conclusion: MT was performed for large-vessel occlusion (LVO) in a COVID-19 patient during the COVID-19 pandemic. Safety for healthcare workers and appropriate rapid treatment for acute stroke patients are both vital in the current environment.

Simple Identification of Cerebrospinal Fluid Turbulent Motion Using a Dynamic Improved Motion-sensitized Driven-equilibrium Steady-state Free Precession Method Applied to Various Types of Cerebrospinal Fluid Motion Disturbance.

The motion of cerebrospinal fluid (CSF) within the subarachnoid space and ventricles is greatly modulated when propagating synchronously with the cardiac pulse and respiratory cycle and path through the nerves, blood vessels, and arachnoid trabeculae. Water molecule movement that propagates between two spaces via a stoma, foramen, or duct presents increased acceleration when passing through a narrow area and can exhibit "turbulence." Recently, neurosurgeons have started to perform fenestration procedures using neuroendoscopy to treat hydrocephalus and cystic lesions. As part of the postoperative evaluation, a noninvasive diagnostic technique to visualize the water molecules at the fenestrated site is necessary. Because turbulence is observed at this fenestrated site, an imaging technique appropriate for observing this turbulence is essential. We therefore investigated the usefulness of a dynamic improved motion-sensitized driven-equilibrium steady-state free precession (Dynamic iMSDE SSFP) sequence of magnetic resonance imaging that is superior for ascertaining turbulent motions in healthy volunteers and patients. Images of Dynamic iMSDE SSFP from volunteers revealed that CSF motion at the ventral surface of the brainstem and the third ventricle is augmented and turbulent. Moreover, our findings confirmed that this technique is useful for evaluating treatments that utilize neuroendoscopy. As a result, Dynamic iMSDE SSFP, a simple sequence for visualizing CSF motion, entails a short imaging time, can extensively visualize CSF motion, does not require additional processes such as labeling or trigger setting, and is anticipated to have wide-ranging clinical applications in the future.

Neuroendoscopic Evacuation for Spontaneous Cerebellar Hemorrhage Is a Safe and Secure Approach and May Become a Mainstream Technique.

Patients with spontaneous cerebellar hemorrhage present with rapidly deteriorating neurological symptoms due to a hematoma-induced mass effect in the brainstem. We compared the standard surgical approach of a suboccipital craniectomy with neuroendoscopic surgery for treating spontaneous cerebellar hemorrhage. We performed a retrospective analysis of 41 patients indicated for surgery to treat spontaneous cerebellar hemorrhage. At our hospital, craniectomy was performed until 2010, and neuroendoscopic surgery was performed thereafter when a qualified surgeon was available. Duration of surgery and intraoperative blood loss were lower in the neuroendoscopic surgery group. The extent of hematoma removal and the percentage of patients requiring shunting were similar between groups. The mass effect was resolved in all patients in both groups, and no substantial re-bleeding was observed in either group. The outcomes at discharge were comparable between the two groups. Our surgeons used the supine lateral position, which involves fewer burdens to the patient than the prone position. Selection of the site of the burr hole is important to avoid the midline and to avoid the area exactly above the transverse and sigmoid sinus. Our results suggest that minimally invasive neuroendoscopic surgery is safe and superior to craniectomy due to shortened duration of surgery and decreased intraoperative bleeding.

Prehospital information and spot sign are complementary predictors of post-admission outcomes of intracerebral hematoma.

Prehospital information of patients with intracerebral hematomas (ICHs), including systolic blood pressure (SBP), Glasgow Coma Scale (GCS), and neurological deterioration (ND), defined as GCS score worsening ≥2 points, has been reported, though relationships among the prehospital information and clinical factors, including the spot sign, which was a reported predictor of outcomes, were not clarified. The purpose of this study was to elucidate relationships among prehospital information, the spot sign, and clinical outcomes after admission using multivariate analysis. Consecutive patients with ICHs admitted within 6 h of onset from 2009 to 2017 were investigated. Among 645 eligible patients, prehospital ND was found in 107 (16.6%). Multiple regression analysis showed that predictors of hematoma volume were prehospital GCS (p < 0.0001), prehospital ND (p < 0.0001), anticoagulant use (p = 0.0254), and cortical hematoma (p < 0.0001). Predictors of emergency surgery or death within 24 h were prehospital SBP (p = 0.0005, unit OR: 1.01), prehospital GCS (p < 0.0001, unit OR: 0.82), prehospital ND (p = 0.0002, OR: 3.26), and hematoma volume (p < 0.0001, unit OR: 1.04). Predictors of death at discharge were prehospital GCS (p < 0.0001, unit OR: 0.75), prehospital ND (p = 0.0001, OR: 3.49), and age (p = 0.0008, unit OR: 1.036). On the other hand, none of the 3 items of prehospital information were predictors of the spot sign or hematoma enlargement. The prehospital information and the spot sign could predict post-admission outcomes in a complementary fashion. Prehospital information might be used as a reference for preparing emergency treatment, as well as possible future blood pressure-lowering treatment, before emergency department arrival.