Ruptured aneurysm in collateral arteries with blood-flow impairment of posterior inferior cerebellar artery: a report of three cases.

Herein, we report three cases of cerebellar hemorrhage due to a ruptured small aneurysm located on a collateral artery compensating for one or more stenotic or occluded major cerebellar arteries. In each case, endovascular distant parent artery occlusion of both the collateral artery and aneurysm was performed to prevent rebleeding. A ruptured small aneurysm in a collateral artery may be observed in patients with hemorrhage in an atypical cerebellar region, especially in cases of stenosis or occlusion of the vertebral artery or posterior inferior cerebellar artery. Thus, cerebral angiography is recommended to rule out collateral artery aneurysm.

Frequency and Characteristics of Paraclinoid Aneurysm in Ruptured Cerebral Aneurysms.

OBJECTIVE: This study aimed to determine the frequency of paraclinoid aneurysms among ruptured cerebral aneurysms and compare paraclinoid aneurysms with other aneurysms to clarify the characteristics of ruptured paraclinoid aneurysms. METHODS: This study included 970 ruptured cerebral aneurysms treated at our hospital between 2003 and 2020. RESULTS: There were 15 cases (1.3%) of paraclinoid aneurysms with maximum diameters of 5-22 mm (mean±standard deviation [SD], 11.6±5.4 mm). Treatment consisted of clipping in four patients and endovascular treatment in 11. Factors significantly different in multivariate analysis for paraclinoid aneurysms compared with those for other aneurysms were a history of hypertension (odds ratio [OR], 1.2-9.8; p=0.021) and aneurysm ≥10 mm (OR, 7.5-390.3; p<0.001). The sites of paraclinoid aneurysm were ophthalmic artery type in nine patients, anterior wall type in five, medial wall type in one, and ventral wall type in zero. The medial wall type (22 mm) was significantly larger than the ophthalmic artery type (mean±SD, 7.2±2.0 mm) (p=0.003), and the anterior wall type (mean±SD, 12.2±4.8 mm) was significantly larger than the ophthalmic artery type (p=0.024). CONCLUSION: This study showed a low frequency of paraclinoid aneurysms among ruptured cerebral aneurysms. Most were upward-facing with relatively large aneurysms, and no aneurysms were smaller than 5 mm. With recent advances in endovascular treatment devices, paraclinoid aneurysms are easily treatable. However, the treatment indication of each paraclinoid aneurysm should be carefully considered.

A Case of Iatrogenic Dural Artery-Pial Vein Shunt Treated with Endovascular Treatment.

Objective: A few cases of postsurgical iatrogenic arteriovenous shunts have been reported, with the arterial blood flow directly entering the pial veins. Herein, we reported a patient with a dural artery-pial vein shunt found 1 year after aneurysmal clipping. Case Presentation: A 64-year-old male presented with generalized convulsion 1 year after cerebral aneurysmal clipping. A CT showed intracerebral hemorrhage in the temporo-occipital cortex and a dural artery-pial vein shunt in proximity to the previous craniotomy center. The arterial blood flow from the deep temporal artery, the middle meningeal artery, and the anterior auricular branch of the superficial temporal artery shunted into the superficial middle cerebral vein, with evident cortical venous reflux. Embolization was performed with n-butyl-2-cyanoacrylate and completely occluded the shunt. The patient was discharged without neurological deficits. Conclusion: Endovascular liquid embolization may be an effective treatment for iatrogenic dural artery-pial vein shunt.

Magnetic Resonance Imaging/Gadolinium-enhanced Vessel Wall Image after Bypass Surgery in Moyamoya Disease.

OBJECTIVE: After bypass surgery in patients with moyamoya disease, several changes on magnetic resonance imaging (MRI)/fluid attenuated inversion recovery (FLAIR) have been recognized, while findings on MRI/gadolinium-enhanced (Gd) vessel wall imaging (VWI) have never been reported. The purposes of this study were to investigate postoperative changes on MRI/Gd VWI and to clarify the relationship between the MRI/Gd VWI and MRI/FLAIR findings. METHODS: Consecutive patients who underwent bypass surgery at our hospital from September 2020 to March 2022 were candidates. RESULTS: In 20 patients with moyamoya disease, 25 operated hemispheres were investigated. In all hemispheres, hyperintensities in the cortical sulci on MRI/FLAIR and enhancement in the cortical sulci on MRI/Gd VWI appeared after bypass surgery. The maximum appearance of sulci enhancement on MRI/Gd VWI occurred earlier than the maximum appearance of the sulci hyperintensity on MRI/FLAIR, and this difference was significant (p = 0.001). CONCLUSIONS: MRI/Gd VWI demonstrated that the peak of the enhancement changes preceded the peak of hyperintensity changes on MRI/FLAIR. These MRI changes may reflect alterations in blood-brain barrier permeability after bypass surgery in patients with moyamoya disease.

Cerebrovascular Reserve Impairment in the Anterior Cerebral Artery Territory Predicts Deep Temporal Artery Enlargement After Combined Revascularization Surgery in Moyamoya Disease.

OBJECTIVE: A combined surgery of direct and indirect revascularization has been frequently performed in patients with moyamoya disease, though the efficacy of indirect revascularization surgery in adult patients with moyamoya disease has not been established. This study aimed to evaluate superficial temporal artery (STA) and deep temporal artery (DTA) diameters 1 day and 3 months after combined revascularization surgery in patients with moyamoya disease. We also investigated clinical factors related to DTA enlargement after surgery. METHODS: We examined 78 cerebral hemispheres in 57 adult and pediatric patients with moyamoya disease who underwent combined revascularization surgery [STA-MCA bypass and encephalo-duro-myo-synangiosis] in our institution. STA and DTA diameters were measured on axial magnetic resonance angiography images at 1 day and 3 months after surgery. RESULTS: DTA diameter increased in 64 hemispheres (82.1%). DTA diameter increase in association with STA diameter decrease was found in 39 hemispheres (50%). The proportion of hemispheres with a reduction in STA diameter was significantly higher in hemispheres with DTA enlargement than in hemispheres with DTA reduction (P = 0.0088). Among the 64 hemispheres with DTA enlargement, 51 (79.7%) showed cerebrovascular reserve (CVR) impairment in the anterior cerebral artery (ACA) territory before surgery. CVR impairment in the ACA territory was the only clinical factor related to DTA enlargement (P < 0.001). CONCLUSION: The DTA frequently enlarges after combined revascularization surgery, even in adult patients with moyamoya disease. In patients with impaired CVR in the ACA territory, blood supply from the DTA to the ACA territory can be expected after combined revascularization surgery.

Nontraumatic Internal Carotid Aneurysms in the Paranasal Sinuses Presenting with Epistaxis: A Case Report.

Epistaxis due to rupture of a nontraumatic internal carotid artery (ICA) aneurysm in the paranasal sinus has rarely been reported. Here, we report a case of double ICA aneurysms located within both the sphenoid and ethmoid sinuses. A 78-year-old woman presented with recurrent massive epistaxis. Magnetic resonance angiogram (MRA) and cerebral angiogram showed two ICA aneurysms: one protruded into the sphenoid sinus and the other protruded into the ethmoid sinus. Intra-aneurysmal coil embolization was performed for both aneurysms. The patient recovered completely, and a follow-up MRA 3 years later showed no recurrence of the aneurysms. Intra-aneurysmal coil embolization is an option of treatment for an ICA aneurysm filling the paranasal sinus.

New-generation tyrosine kinase inhibitor-associated asymptomatic cerebrovascular stenosis: two illustrative cases.

New-generation tyrosine kinase inhibitors (TKIs), nilotinib and ponatinib, for chronic myelogenous leukemia (CML) have been reported to cause symptomatic cerebral ischemia. Herein, we report two patients with asymptomatic cerebral artery stenosis associated with these TKIs, as a previously unreported finding. Both patients were in their 40 s and administered new-generation TKIs without vascular risk factors. New-generation TKIs for CML can cause major cerebrovascular stenosis without any symptoms. Examining the neck and intracranial arteries using magnetic resonance angiography and carotid ultrasonography may prevent future cerebral infarctions associated with these TKIs.

Microcatheter Re-Shaping Using Fusion Image in Coil Embolization: A Technical Note.

Objective: We report the utility of microcatheter reshaping by referring to fusion images with 3D-DSA and microcatheter 3D images made using non-subtraction and non-contrast (non-SC) rotational images. Case Presentations: Case 1: The patient was a 74-year-old man who had an internal carotid-anterior choroidal artery bifurcation aneurysm with a tortuous proximal parent artery. The initial attempt to introduce the microcatheter into the aneurysm was unsuccessful. During this unsuccessful microcatheter introduction, we created fusion images with 3D-DSA and microcatheter 3D images by acquiring positional information of the microcatheter using the non-SC method. By reshaping the microcatheter with reference to the fusion images, the direction of the distal end of the microcatheter was reshaped to be in accordance with the long axis of the aneurysm, a shape more suitable for coiling. Case 2: The patient was a 47-year-old man who had an anterior communicating (A-com) artery aneurysm with two daughter sacs. We successfully placed two microcatheters in the direction of each sac to make more stable framing by referring to 3D fusion images after the first microcatheter was positioned. In both cases, microcatheter reshaping was necessary because of the vessel and aneurysm anatomy. We have used this technique successfully in 15 patients, for both ruptured and unruptured aneurysms. The average number of microcatheter reshaping was 1.3 times. Conclusion: This method provides effective microcatheter reshaping for coil embolization of aneurysms, particularly those with differences between the axis of the parent artery and the vertical axis of aneurysm, or with a tortuous proximal artery.

Diagnostic Tests for COVID-19 and Their Accuracy: Important Information for Physicians Caring for Patients with Stroke.

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SAR-CoV-2), which appeared at the end of 2019 and has spread rapidly worldwide. In Japan, the increasing number of people infected with SAR-CoV-2 is also a cause of concern for physicians managing stroke patients. From the perspective of viral transmission in the hospital, stroke physicians must determine whether patients who have been transported by emergency have confirmed or suspected COVID-19. For this reason, stroke physicians must also understand about the characteristics and accuracy of the test for COVID-19 diagnosis. This article describes the sensitivity of the clinical symptoms, imaging investigations such as chest radiography and chest CT, and accuracy of nucleic-acid amplification tests and antigen tests used in the diagnosis of COVID-19. However, it should be noted that the accuracy of specimen tests may change depending on the collection site, timing, and method, because positive results in these tested specimens depend on the viral loads. In performing medical treatment for stroke, high accuracy and rapid inspection for COVID-19 is desired, but this is not currently available. For acute stroke treatment, such as thrombectomy, we recommend that these emergency patients, who are suspected of COVID-19 by clinical symptoms and image investigations, should be treated with implementation of strict infection control against droplets, contact, and airborne transmission until the most sensitive polymerase chain reaction test result is confirmed as negative.

Heterochrony and growth rate variation mediate the development of divergent genital morphologies in closely related Ohomopterus ground beetles.

The rapid divergence of genital morphology is well studied in the context of sexual selection and speciation; however, little is known about the developmental mechanisms underlying divergence in genitalia. Ground beetles in the subgenus Ohomopterus genus Carabus have species-specific genitalia that show coevolutionary divergence between the sexes. In this study, using X-ray microcomputed tomography, we examined the morphogenesis of male and female genitalia in two closely related Ohomopterus species with divergent genital morphologies. The morphogenetic processes generating the male and female genitalia at the pupal stage were qualitatively similar in the two species. The male aedeagus and internal sac and female bursa copulatrix were partially formed at pupation and developed gradually thereafter. The species-specific genital parts, male copulatory piece, and female vaginal appendix differed in the timing and rate of development. The relatively long copulatory piece of Carabus maiyasanus began to develop earlier, but subsequent rates of growth were similar in the two species. The timing of the formation of the vaginal appendix and initial growth rates were similar, but subsequent rapid growth led to a longer vaginal appendix in C. maiyasanus. Thus, substantial interspecific differences in the size of genital parts were mediated by different underlying developmental mechanisms between the sexes (i.e., a shift in the developmental schedule in males and a change in growth rate in females). These results revealed the spatio-temporal dynamics of species-specific genital structure development, providing a novel platform for evo-devo studies of the diversification of genital morphologies.

A Protocol of Infection Control for Mechanical Thrombectomy in Possible COVID-19 Patients: Tokai University COVID-19 Manual.

The crisis of the coronavirus disease (COVID-19) is causing damage to the social and medical community. However, extreme emergency neuro-interventions such as mechanical thrombectomy still require the healthcare workers to offer the appropriate treatment while preventing further spread of the infection. This article outlines the necessary steps in managing a possible COVID-19 patient starting from patient screening to personnel infection and environmental contamination measures.

Benefits and Risks of CT Angiography Immediately after Emergency Arrival for Patients with Intracerebral Hematoma.

Computed tomography angiography (CTA) immediately after diagnosis of intracerebral hematoma (ICH) on noncontrast CT in the emergency room has benefits, which consist of early diagnosis of secondary ICH and prediction of hematoma growth using the spot sign in primary ICH, but CTA also involves possible risks of acute kidney injury (AKI) and adverse reactions. The purpose of this study was to evaluate the benefits and risks of CTA. A total of 1423 consecutive adult patients diagnosed with ICH who were admitted within 3 days of onset between 2010 and 2017 were retrospectively analyzed. Of 1082 patients undergoing CTA, 162 patients (15.0%) showed secondary ICH, and the sensitivity of CTA for secondary ICH was 95.7%. Of 920 patients with primary ICH, a logistic regression model using the spot sign and four other previously reported risk factors (antiplatelet agents, anticoagulants, interval from onset to arrival, hematoma volume) with an area under the curve (AUC) of 0.787 significantly improved model performance to predict hematoma growth compared with a model using the same four factors without the spot sign (AUC: 0.697) (DeLong's test: P = 0.0002). Rates of AKI occurrence were 9.0% and 9.8% in patients with and without CTA, respectively. The odds ratio of AKI in patients with CTA adjusted by reported risk factors was 1.16 (95% confidence interval: 0.72-1.95, P = 0.5548). Emergency CTA following noncontrast CT in patients with ICH could be useful for early diagnosis of secondary ICH and prediction of hematoma growth using the spot sign in primary ICH with little risk.

Changing the Currently Held Concept of Cerebrospinal Fluid Dynamics Based on Shared Findings of Cerebrospinal Fluid Motion in the Cranial Cavity Using Various Types of Magnetic Resonance Imaging Techniques.

The "cerebrospinal fluid (CSF) circulation theory" of CSF flowing unidirectionally and circulating through the ventricles and subarachnoid space in a downward or upward fashion has been widely recognized. In this review, observations of CSF motion using different magnetic resonance imaging (MRI) techniques are described, findings that are shared among these techniques are extracted, and CSF motion, as we currently understand it based on the results from the quantitative analysis of CSF motion, is discussed, along with a discussion of slower water molecule motion in the perivascular, paravascular, and brain parenchyma. Today, a shared consensus regarding CSF motion is being formed, as follows: CSF motion is not a circulatory flow, but a combination of various directions of flow in the ventricles and subarachnoid space, and the acceleration of CSF motion differs depending on the CSF space. It is now necessary to revise the currently held concept that CSF flows unidirectionally. Currently, water molecule motion in the order of centimeters per second can be detected with various MRI techniques. Thus, we need new MRI techniques with high-velocity sensitivity, such as in the order of 10 µm/s, to determine water molecule movement in the vessel wall, paravascular space, and brain parenchyma. In this paper, the authors review the previous and current concepts of CSF motion in the central nervous system using various MRI techniques.

Preservation of Anterior Choroidal Artery Blood Flow During Trapping of the Internal Carotid Artery for a Ruptured Blood Blister-Like Aneurysm with High-Flow Bypass.

BACKGROUND: The ideal surgery for a blood blister-like aneurysm (BBA) in the internal carotid artery (ICA) involves complete termination of blood flow into the BBA by trapping of the ICA at sites both proximal and distal to the BBA. In the present report, we describe a clipping method with ICA trapping for prevention of anterior choroidal artery ischemia, a major problem in ICA trapping with reconstruction surgery using external carotid artery-middle cerebral artery high-flow bypass (HFB). METHODS: The data from patients with a ruptured BBA treated by the combination of ICA trapping and blood flow reconstruction from 2008 to 2018 were retrospectively evaluated. RESULTS: Fifteen patients had been treated with the combination surgery. Clip placement for ICA trapping depended on the relationship between the distal neck of the BBA and the posterior communicating artery. In the case of the BBA distal neck located at the same level or distal to the posterior communicating artery, oblique placement of a distal clip to the ICA was mandatory to maintain blood flow of the anterior choroidal artery. No patients developed recurrence of the BBA after trapping. The outcomes were assessed using the modified Rankin scale score, with a score of 0 or 1 in 12 of the 15 patients (80%). CONCLUSIONS: A complete shutdown of blood flow to the BBA by ICA trapping is essential for the permanent prevention of BBA recurrence. In cases of a BBA distal neck located distal to the posterior communicating artery, the oblique clipping technique applied to the ICA is useful to prevent ischemic complications of the anterior choroidal artery.

Hemiparesis without Responsible Hematomas in Patients with Subarachnoid Hemorrhage Undergoing Early Aneurysmal Repair.

OBJECTIVE: The presence of hemiparesis on arrival in patients with subarachnoid hemorrhage (SAH) is presumed to affect prognosis; intracranial hematomas with mass effect responsible for hemiparesis are frequently observed in these patients. The aim of this study was to clarify characteristics and outcomes of patients who presented with hemiparesis on arrival with no responsible hematomas (hemiparesis without hematoma) having mass effect demonstrated on computed tomography. METHODS: Consecutive patients with SAH treated with surgery for ruptured cerebral aneurysms within 5 days of onset between 2003 and 2015 were retrospectively reviewed. RESULTS: Hemiparesis without hematoma was present in 25 of 858 surgically treated patients (2.9%). Internal carotid artery aneurysms were significantly more common in patients with hemiparesis without hematoma than in the other patients (P < 0.05). In 19 of 21 surviving patients (90.5%) with hemiparesis without hematoma on arrival, the hemiparesis improved at discharge. Favorable outcomes were achieved in 16 of 25 patients with hemiparesis without hematoma (64%) and in 13 of 59 patients with hemiparesis with hematomas (22.0%); this difference was significant (P < 0.05). CONCLUSIONS: Hemiparesis can be expected to improve in patients with SAH with hemiparesis without hematoma, and such patients appear to have a better prognosis than patients with SAH with hemiparesis and responsible hematomas. A possible major mechanism of hemiparesis without hematoma based on the characteristics identified is a combination of transient ipsilateral hemispheric functional failure caused by the impact of aneurysmal rupture and transient ischemia of the perforators originating from the internal carotid artery.

Clinical significance of centripetal propagation of vasoconstriction in patients with reversible cerebral vasoconstriction syndrome: A retrospective case-control study.

Introduction We previously reported centripetal propagation of vasoconstriction at the time of thunderclap headache remission in patients with reversible cerebral vasoconstriction syndrome. Here we examine the clinical significance of centripetal propagation of vasoconstriction. Methods Participants comprised 48 patients who underwent magnetic resonance angiography within 72 h of reversible cerebral vasoconstriction syndrome onset and within 48 h of thunderclap headache remission. Results In 24 of the 48 patients (50%), centripetal propagation of vasoconstriction occurred on magnetic resonance angiography at the time of thunderclap headache remission. The interval from first to last thunderclap headache in patients with centripetal propagation of vasoconstriction (14 ± 10 days) was significantly longer than that of patients without centripetal propagation of vasoconstriction (4 ± 2 days). In the patients with centripetal propagation of vasoconstriction at the time of thunderclap headache remission, the incidence of another cerebral lesion (38%, 9 of 24 cases) was significantly higher than in patients without centripetal propagation of vasoconstriction (0%). From findings of sequential magnetic resonance angiography before and after thunderclap headache remission, we observed tendencies in which centripetal propagation of vasoconstriction gradually progressed after the onset of reversible cerebral vasoconstriction syndrome and peaked at the time of thunderclap headache remission. The progress of centripetal propagation of vasoconstriction concluded with thunderclap headache remission. Conclusions Centripetal propagation of vasoconstriction has clinical significance as an indicator of the severity of reversible cerebral vasoconstriction syndrome. The presence of centripetal propagation of vasoconstriction is associated with an increased risk of brain lesions and a longer interval from first to last thunderclap headache. Moreover, repeat magnetic resonance angiography to assess centripetal propagation of vasoconstriction during the time from onset to thunderclap headache remission can help diagnose reversible cerebral vasoconstriction syndrome.

Retrospective review of previous minor leak before major subarachnoid hemorrhage diagnosed by MRI as a predictor of occurrence of symptomatic delayed cerebral ischemia.

OBJECTIVE This study attempted to determine whether a previous minor leak correlated with the occurrence of symptomatic delayed cerebral ischemia (sDCI). METHODS The authors retrospectively evaluated sDCI-related clinical features and findings from MRI, including T1-weighted imaging (T1WI)-FLAIR mismatch at the time of admission, in 151 patients admitted with subarachnoid hemorrhage (SAH) within 48 hours of ictus. RESULTS The overall incidence of sDCI was 23% (35 of 151 patients). In all subjects, multivariate analysis revealed that World Federation of Neurosurgical Societies Grades II-V, age 70 years or older, presence of rebleeding after admission, a previous minor leak before the major SAH attack as diagnosed by T1WI-FLAIR mismatch, acute infarction on diffusion-weighted imaging, and CT SAH score were significantly associated with occurrence of sDCI. In patients with no previous minor leak before major SAH as diagnosed by T1WI-FLAIR mismatch, the incidence of sDCI was only 7% (7 of 97 patients). CONCLUSIONS A previous minor leak before major SAH as diagnosed by T1WI-FLAIR mismatch represents an important sDCI-related factor. When the analysis was restricted to patients with true acute SAH without a previous minor leak diagnosed by T1WI-FLAIR mismatch, the incidence of sDCI was extremely low.

Cardiac-driven Pulsatile Motion of Intracranial Cerebrospinal Fluid Visualized Based on a Correlation Mapping Technique.

PURPOSE: A correlation mapping technique delineating delay time and maximum correlation for characterizing pulsatile cerebrospinal fluid (CSF) propagation was proposed. After proofing its technical concept, this technique was applied to healthy volunteers and idiopathic normal pressure hydrocephalus (iNPH) patients. METHODS: A time-resolved three dimensional-phase contrast (3D-PC) sampled the cardiac-driven CSF velocity at 32 temporal points per cardiac period at each spatial location using retrospective cardiac gating. The proposed technique visualized distributions of propagation delay and correlation coefficient of the PC-based CSF velocity waveform with reference to a waveform at a particular point in the CSF space. The delay time was obtained as the amount of time-shift, giving the maximum correlation for the velocity waveform at an arbitrary location with that at the reference location. The validity and accuracy of the technique were confirmed in a flow phantom equipped with a cardiovascular pump. The technique was then applied to evaluate the intracranial CSF motions in young, healthy (N = 13), and elderly, healthy (N = 13) volunteers and iNPH patients (N = 13). RESULTS: The phantom study demonstrated that root mean square error of the delay time was 2.27%, which was less than the temporal resolution of PC measurement used in this study (3.13% of a cardiac cycle). The human studies showed a significant difference (P < 0.01) in the mean correlation coefficient between the young, healthy group and the other two groups. A significant difference (P < 0.05) was also recognized in standard deviation of the correlation coefficients in intracranial CSF space among all groups. The result suggests that the CSF space compliance of iNPH patients was lower than that of healthy volunteers. CONCLUSION: The correlation mapping technique allowed us to visualize pulsatile CSF velocity wave propagations as still images. The technique may help to classify diseases related to CSF dynamics, such as iNPH.

The Choroid Plexus of the Lateral Ventricle As the Origin of CSF Pulsation Is Questionable.

The advent of magnetic resonance imaging (MRI) enables noninvasive measurement of cerebrospinal fluid (CSF) motion, and new information about CSF motion has now been acquired. The driving force of the CSF has long been thought to be choroid plexus (CP) pulsation, but to investigate whether this phenomenon actually occurs, CSF motion was observed in the ventricular system and subarachnoid space using MRI. Eleven healthy volunteers, ranging in age from 23 to 58 years, participated in this study. The MRI sequences used were four-dimensional phase-contrast (4D-PC) and time-spatial labeling inversion pulse (t-SLIP). The 4D-PC images included sagittal images in the cranial midline, coronal images focusing on the foramen of Monro (FOM), and oblique coronal images of the trigone to quantify CSF velocity and acceleration. These values were compared and analyzed as non-parametric data using the Kolmogorov-Smirnov test and the Mann-Whitney U test. 4D-PC showed that the median CSF velocity was significantly lower in the posterior part of the lateral ventricle than in other regions. The quantitative analysis of velocity and acceleration showed that they were decreased around the CP in the trigone. Image analysis of both velocity mapping and t-SLIP showed suppressed CSF motion around the CP in the trigone. These findings cast doubt on CP pulsation being the driving force for CSF motion.

Hyperdynamic CSF motion profiles found in idiopathic normal pressure hydrocephalus and Alzheimer's disease assessed by fluid mechanics derived from magnetic resonance images.

BACKGROUND: Magnetic resonance imaging (MRI) does not only ascertain morphological features, but also measures physiological properties such as fluid velocity or pressure gradient. The purpose of this study was to investigate cerebrospinal fluid (CSF) dynamics in patients with morphological abnormalities such as enlarged brain ventricles and subarachnoid spaces. We used a time-resolved three dimensional phase contrast (3D-PC) MRI technique to quantitatively evaluate CSF dynamics in the Sylvian aqueduct of healthy elderly individuals and patients with either idiopathic normal pressure hydrocephalus (iNPH) or Alzheimer's disease (AD) presenting with ventricular enlargement. METHODS: Nineteen healthy elderly individuals, ten iNPH patients, and seven AD patients (all subjects ≥ 60 years old) were retrospectively evaluated 3D-PC MRI. The CSF velocity, pressure gradient, and rotation in the Sylvian aqueduct were quantified and compared between the three groups using Kolmogorov-Smirnov and Mann-Whitney U tests. RESULTS: There was no statistically significant difference in velocity among the three groups. The pressure gradient was not significantly different between the iNPH and AD groups, but was significantly different between the iNPH group and the healthy controls (p < 0.001), and similarly, between the AD group and the healthy controls (p < 0.001). Rotation was not significantly different between the iNPH and AD groups, but was significantly different between the iNPH group and healthy controls (p < 0.001), and similarly, between the AD group and the healthy controls (p < 0.001). CONCLUSIONS: Quantitative analysis of CSF dynamics with time resolved 3D-PC MRI revealed differences and similarities in the Sylvian aqueduct between healthy elderly individuals, iNPH patients, and AD patients. The results showed that CSF motion is in a hyperdynamic state in both iNPH and AD patient groups compared to healthy elderly individuals, and that iNPH patients and AD patients display similar CSF motion profiles.