Time-spatial Labeling Inversion Pulse Research Articles

The significance of cerebrospinal fluid dynamics in adolescent idiopathic scoliosis using time-SLIP MRI

Adolescent idiopathic scoliosis (AIS) affects approximately 3% of the global population. Recent studies have drawn attention to abnormalities in the dynamics of the CSF as potential contributors. This research aims to employ the Time-Spatial Labeling Inversion Pulse (Time-SLIP) MRI to assess and analyze cerebrospinal fluid (CSF) dynamics in AIS patients. 101 AIS patients underwent Time-SLIP MRI. Images were taken at the mid-cervical and craniocervical junction regions. The sum of the maximum movement distances of CSF on the ventral and dorsal sides of the spinal canal within a single timeframe was defined and measured as Travel Distance (TD). Correlations between TD, age, Cobb angle, and Risser grade were analyzed. TD comparisons were made across Lenke classifications. TD for all patients was a weak correlation with the Cobb angle (r = − 0.16). Comparing TD between Lenke type 1 and 5, type 5 patients display significantly shorter TD (p < 0.05). In Risser5 patients with Lenke type 5 showed a significant negative correlation between Cobb angle and TD (r = − 0.44). Lenke type 5 patients had significantly shorter CSF TD compared to type1, correlating with worsening Cobb angles. Further analysis and exploration are required to understand the mechanism of onset and progression.

Radiological Analysis of Cerebrospinal Fluid Dynamics at the Craniovertebral Junction Using Time-Spatial Labeling Inversion Pulse Magnetic Resonance Imaging in Patients with Cervical Spinal Canal Stenosis

ObjectiveSpondylotic changes in the cervical spine cause degeneration, leading to cervical spinal canal stenosis. This stenotic change can affect cerebrospinal fluid (CSF) dynamics by compressing the dural sac and reducing space in the subarachnoid space. We examined CSF dynamics at the craniovertebral junction (CVJ) using time-spatial labeling inversion pulse magnetic resonance imaging (Time-SLIP MRI) in patients with cervical spinal canal stenosis. MethodsThe maximum longitudinal movement of the CSF at the CVJ was measured as length of motion (LOM) in the Time-SLIP MR image of 56 patients. The sum of ventral and dorsal LOM was defined as the total LOM. Patients were classified into three groups depending on their spinal sagittal MRI findings: control (n=27, Kang classification grades 0 and 1), stenosis (n=14, Kang classification grade 2), and severe stenosis (n=15, Kang classification grade 3). ResultsTime-SLIP MRI revealed pulsatile movement of the CSF at the CVJ. The mean total, ventral, and dorsal LOM was 14.2 ± 9, 8.1 ± 5.7, and 3.8 ± 2.9 mm, respectively. The ventral LOM was significantly larger than the dorsal LOM. The total LOM was significantly smaller in the severe stenosis group (6.1 ± 3.4 mm) than in the control (16.0 ± 8.4 mm) or stenosis (11 ± 5.4 mm) groups (p < 0.001, Kruskal–Wallis H-test). In five patients, postoperative total LOM was improved after adequate decompression surgery. ConclusionsThis study demonstrates that CSF dynamics at the CVJ are influenced by cervical spinal canal stenosis. Time-SLIP MRI is useful for evaluating CSF dynamics at the CVJ in patients with spinal canal stenosis.

Preoperative examination and intraoperative cerebrospinal fluid leakage test for minimally invasive surgery of spinal extradural arachnoid cysts: illustrative case.

Spinal extradural arachnoid cysts (SEACs) are rare and can cause spinal dysfunction. Total cyst removal and duraplasty via multiple laminectomies are commonly performed. However, to avoid postoperative spinal deformity and axial pain, a minimally invasive surgery via selective laminectomy may be optimal. Therefore, preoperative detection of the dural fistula site is required. A 25-year-old male presented with a 2-month history of progressive gait disturbance and back pain. Conventional magnetic resonance imaging (MRI) revealed SEACs at the T9 to L2 level but did not reveal the dural fistula. Further examinations were performed using sagittal time-spatial labeling inversion pulse MRI and cone-beam computed tomography myelography with a spinal intrathecal catheter, which indicated a dural fistula on the left side at the T12 level. On the basis of these results, dural repair was performed via selective laminectomy. Furthermore, an intraoperative cerebrospinal fluid leakage test by intrathecally injecting saline via a spinal catheter confirmed complete closure of the dural fistula, with no other fistulas. These comprehensive pre and intraoperative examinations may be useful for minimally invasive and selective surgeries in patients with SEACs.

T-Slip (Time-spatial Labeling Inversion Pulse) in the diagnosis of renal artery stenosis by magnetic resonance imaging

T-Slip (Time-spatial Labeling Inversion Pulse) in the diagnosis of renal artery stenosis by magnetic resonance imaging

Comparison of Access Route for Endovascular Treatment by Time-Spatial Labeling Inversion Pulse (Time-SLIP) MRA and Contrast-Enhanced MRA.

In endovascular treatment, it is important to evaluate the access route for placing a catheter into the common carotid artery (CCA) promptly and safely prior to the procedure. We examined whether non-contrast MRA using time-spatial labeling inversion pulse (Time-SLIP) can be used in patients prior to endovascular thrombectomy for acute ischemic stroke. We compared Time-SLIP MRA to contrast-enhanced (CE) MRA and evaluated the efficacy in the evaluation of access routes. We retrospectively reviewed 31 patients admitted between October 2018 and December 2018 for cerebral infarction at our hospital. Blood vessels were imaged from the aortic arch to the CCA. A radiologist blindly evaluated quality score, stenosis, shape of the aorta, and degree of tortuosity. There were no "non-diagnostic" images. The sensitivity, specificity, positive predictive value, and negative predictive value for stenosis were 83%, 96%, 83%, and 96%, respectively. The sensitivity for the aorta type classification was 100%. The sensitivity for mild tortuosity was 93%, for moderate was 100%, and for severe was 100%. Time-SLIP MRA can be an alternative to CE MRA in access route assessment for patients with cerebral infarction who are not eligible for acute thrombectomy therapy.

Comparison of Slab and Pencil Beam Labeling in Spin-labeled MR Imaging for Pancreatic Juice Flow Visualization.

The usefulness of a highly targeted pencil beam (PB) label was compared with the commonly used slab label for direct visualization of pancreaticobiliary reflux using the time-spatial labeling inversion pulse (time-SLIP) technique. Signal profiles of flow phantom images obtained with a 1.5T MRI were analyzed. Both labels had similar labeling capabilities, but the edge characteristics of the PB label were blunt. Next, sixty-eight patients were classified into two groups according to the angle of the pancreaticobiliary ducts, and the displacement of the pancreatic ducts in respiratory fluctuation was measured. The results were approximately 7 mm in both groups. The blunt edge characteristics of the PB label suggest that it is robust to respiratory fluctuations. The overall labeling ability of the PB is comparable to that of the slab. In the larger angle of pancreaticobiliary ducts, the PB label may be able to label the pancreatic duct more selectively.

Using Spin-labeled MR Imaging to Depict Slow Pancreatic Juice Flow.

This study evaluated the dependence of the signal characteristics of time-spatial labeling inversion pulse (time-SLIP) on flow velocity and tag thickness to depict the pancreatic juice flow by analyzing signal profile using a tube phantom study. The tag edge property was evaluated by edge rise distance (ERD). For various slow flow velocities and tag thicknesses, the signal profile characteristics were evaluated using two indices: the tag center value (RTCV) reduction rate and the total signal value along the tube (TSVT). ERD, which was about 10% of the tag thickness, was higher for thicker tags, making slow flow detection difficult. TSVT was proportional to the thickness of the tag and was preserved irrespective of the flow velocity. RTCV became lower with higher flow velocity and decreased significantly with thinner tags. These results suggest that the visualization of pancreatic juice flow might improve stability by considering the appropriate tag thickness.

Visualization of Peripheral Blood Vessels on the Lingual Aspect of the Mandible Using a Balanced Steady-State Free-Precession Sequence with a Time-Spatial Labeling Inversion Pulse: Usefulness for Prevention of Severe Complications of Dental Implantation.

The aim of this study was to evaluate whether a balanced steady-state free-precession (SSFP) sequence with a time–spatial labeling inversion pulse (time–SLIP) without contrast medium could elucidate branches of the lingual and facial arteries on the lingual aspect of the mandible as a potential technique for preventing severe complications in dental implantation surgery. In this study, magnetic resonance angiography (MRA) using SSFP with a time–SLIP was evaluated in 40 subjects. The outline and course of branches of the lingual and facial arteries near the mandible were assessed clinically in the same subjects against contrast-enhanced computed tomography (CT) images as the gold standard. The submental, sublingual, and deep lingual arteries could be visualized via MRA in 16, 20, and 16 of the 40 subjects, respectively. The major axes of the respective arteries were approximately 24, 24, and 16 mm. The outline and course of all visualized arteries coincided with those on CT. MRA using SSFP with a time–SLIP appears to have potential as a non-contrast technique for visualizing branches of the lingual and facial arteries on the lingual aspect of the mandible. Information regarding the outline and course of these arteries as obtained using this MRA technique could assist in preventing severe complications in dental implantation surgery.

Evaluation of cerebrospinal fluid flow by phase-contrast technique

Objective The objective of this study was to evaluate cerebrospinal fluid (CSF) flow by phase-contrast technique. Background Multiple CSF flow disorders are present like normal pressure hydrocephalus (NPH), atrophic brain changes, communicating hydrocephalus, aqueductal stenosis, and others. Routine MRI as well as new techniques like steady-state free precession sequence, 2D phase-contrast cine MRI, and 2D time spatial labeling inversion pulse can be used to evaluate these CSF flow disorders. Patients and methods This was a case–control study and included 50 patients and 10 healthy volunteers as a control group. All were referred to the radiodiagnosis departments at Menoufia University Hospital and Tanta University Hospital from July 2017 to August 2019. Results This study revealed that CSF flowmetry can differentiate between NPH and atrophic brain changes by the value of stroke volume, where the normal range was 10–21 μl, and all cases of atrophic brain changes showed stroke volume less than 10 μl, where all cases of NPH showed stroke volume more than 21 μl. This study can also confirm the diagnosis of aqueductal stenosis and differentiate it from communicating hydrocephalus (cases of aqueductal stenosis showed stroke volume less than 10 μl, where communicating hydrocephalus showed stroke volume is between 10 and 1 μl). It was also useful in follow-up of patients with endoscopic third ventriculostomy by detection of stroke volume through the third ventricular floor stoma. Conclusion The study showed usefulness of this investigation for confirmation of diagnosis of various CSF disorders. Cine phase-contrast MRI studies, however, should be interpreted in conjunction with the clinical manifestations and the conventional MRI findings in cases of ventriculomegaly. The technique enables measuring aqueductal flow parameters in a reliable and reproducible way and predicts response to shunting and also allows accurate follow-up results.

Cerebrospinal fluid flow in normal beagle dogs analyzed using magnetic resonance imaging.

BackgroundDiseases related to cerebrospinal fluid flow, such as hydrocephalus, syringomyelia, and Chiari malformation, are often found in small dogs. Although studies in human medicine have revealed a correlation with cerebrospinal fluid flow in these diseases by magnetic resonance imaging, there is little information and no standard data for normal dogs.ObjectivesThe purpose of this study was to obtain cerebrospinal fluid flow velocity data from the cerebral aqueduct and subarachnoid space at the foramen magnum in healthy beagle dogs.MethodsSix healthy beagle dogs were used in this experimental study. The dogs underwent phase-contrast and time-spatial labeling inversion pulse magnetic resonance imaging. Flow rate variations in the cerebrospinal fluid were observed using sagittal time-spatial labeling inversion pulse images. The pattern and velocity of cerebrospinal fluid flow were assessed using phase-contrast magnetic resonance imaging within the subarachnoid space at the foramen magnum level and the cerebral aqueduct.ResultsIn the ventral aspect of the subarachnoid space and cerebral aqueduct, the cerebrospinal fluid was characterized by a bidirectional flow throughout the cardiac cycle. The mean ± SD peak velocities through the ventral and dorsal aspects of the subarachnoid space and the cerebral aqueduct were 1.39 ± 0.13, 0.32 ± 0.12, and 0.76 ± 0.43 cm/s, respectively.ConclusionsNoninvasive visualization of cerebrospinal fluid flow movement with magnetic resonance imaging was feasible, and a reference dataset of cerebrospinal fluid flow peak velocities was obtained through the cervical subarachnoid space and cerebral aqueduct in healthy dogs.

Ultrashort echo time time-spatial labeling inversion pulse magnetic resonance angiography with denoising deep learning reconstruction for the assessment of abdominal visceral arteries.

Current contrast-enhanced magnetic resonance angiography (MRA) and non-contrast-enhanced balanced steady-state free precession (bSSFP) MRA cause susceptibility artifacts from metallic devices in assessing endovascular visceral-artery interventions. The aims of this study are to investigate and compare image quality (IQ) and susceptibility artifacts of three-dimensional (3D) ultrashort echo time (UTE) time-spatial labeling inversion pulse (Time-SLIP) with those of 3D bSSFP Time-SLIP and to assess denoising deep learning reconstruction (dDLR) for the improvement of the signal-to-noise ratio (SNR) in 3D UTE with sparse sampling in phantoms and human subjects. This is a prospective type of study. Pulsatile glycerin-water flow phantom with platinum-tungsten-alloy coil, stainless-steel, nitinol, and cobalt-alloy stents were used. Ten healthy volunteers (seven males) and three patients (two males) were included in this study. 3D UTE Time-SLIP and 3D bSSFP Time-SLIP at 3T were used. The phantom-based study compared the signal-intensity ratio of the device levels (SRdevice ) and distal segments (SRdistal ) to the proximal segments. The volunteer-based study measured SNR, contrast ratio (CR), and IQ. The patient study evaluated local artifacts from metallic devices. Statistical tests included paired t-tests, Wilcoxon-signed rank tests, and Kruskal-Wallis tests. In the phantom-based study, SRdevice was small with UTE Time-SLIP, except the stainless-steel stent. SRdistal was greater (49.1%-90.4%) on bSSFP images than UTE images (-11.1% to 9.6%). Among volunteers, dDLR in UTE images improved SNR (p < 0.05) and IQ (p < 0.05), but CR was unaffected. UTE Time-SLIP showed inferior SNR and IQ than bSSFP Time-SLIP in images with and without dDLR (p < 0.05 for each). However, among patients, UTE Time-SLIP showed reduced metal artifacts compared to bSSFP Time-SLIP. Irrespective of the lower SNR and IQ of 3D UTE Time-SLIP than those of 3D bSSFP Time-SLIP, the former appeared to better depict flow after stenting or coiling. This indicates the potential of 3D UTE Time-SLIP to provide suitable diagnostic images of target vessels. dDLR improved SNR with reducing artifacts related to radial sampling, while maintaining the contrast. LEVEL OF EVIDENCE: 2. TECHNICAL EFFICACY STAGE: 2.

Comparison of axial and coronal acquisitions by non-contrast-enhanced renal 3D MR angiography using flow-in time-spatial labeling inversion pulse

ObjectiveWe evaluated image quality differences between axial and coronal non-contrast-enhanced renal three-dimensional (3D) magnetic resonance angiography (MRA) acquisitions, using time-spatial labeling inversion pulse (Time-SLIP) with flow-in balanced steady-state free precession (bSSFP).Materials and methodsAxial and coronal images were acquired in 128 subjects using non-contrast-enhanced 3D-MRA with Time-SLIP flow-in bSSFP on a clinical 1.5-T MRI system. Visualization of source and maximum intensity projection (MIP) images of renal arteries were compared between the axial and coronal acquisitions using a four-point scale. For quantitative analysis, vessel-to-background contrast ratios of aorta and renal arteries were calculated.ResultsBoth acquisitions yielded similarly excellent quality. In source image evaluation, coronal acquisitions showed significantly more motion degradation (p < 0.01) than did axial acquisitions. In MIP image evaluation, coronal acquisitions yielded superior image quality, less motion degradation, and better visualization of the number of renal branches than did axial acquisition. The renal artery to background signal contrast was greater in coronal than in axial acquisitions (p < 0.01).ConclusionCoronal acquisition provides superior contrast between the renal arteries and background and allows more persistent visualization than axial acquisitions in non-contrast-enhanced MRA using flow-in bSSFP with Time-SLIP. First-line screening of renal non-contrast-enhanced MRA should involve coronal acquisition.

Non-contrast MR portography using time-spatial labeling inversion pulse for diagnosis of portal vein pathology

BackgroundTo study the ability of non-contrast MR portography using time-spatial labeling inversion pulse (T-SLIP) as a non-invasive contrast-free imaging modality to delineate different portal vein pathological conditions.The study included 25 patients with known history of portal vein disease and another 25 age-matched patients with normal portal vein. Both groups were examined by respiratory-triggered non-contrast MR portography using time-spatial labeling inversion pulse technique. Image quality was assessed first, and findings of diagnostic scans were compared to color duplex ultrasonography and selectively in those with diseased portal vein to portal-phase images of dynamic contrast-enhanced MRI.ResultsSignificant relation was found between breathing regularity and image quality in T-SLIP sequence, with diagnostic scans sensitivity and specificity of 89.29% and 86.21%, respectively, for diagnosis of different portal vein pathological conditions.ConclusionsNon-contrast MR portography is a useful technique for diagnosis of portal vein pathology in carefully selected patients.

Recent Advances in Rational Diagnosis and Treatment of Normal Pressure Hydrocephalus: A Critical Appraisal on Novel Diagnostic, Therapy Monitoring and Treatment Modalities.

Normal pressure hydrocephalus (NPH) is a critical brain disorder in which excess Cerebrospinal Fluid (CSF) is accumulated in the brain's ventricles causing damage or disruption of the brain tissues. Amongst various signs and symptoms, difficulty in walking, slurred speech, impaired decision making and critical thinking, and loss of bladder and bowl control are considered the hallmark features of NPH. The current review was aimed to present a comprehensive overview and critical appraisal of majorly employed neuroimaging techniques for rational diagnosis and effective monitoring of the effectiveness of the employed therapeutic intervention for NPH. Moreover, a critical overview of recent developments and utilization of pharmacological agents for the treatment of hydrocephalus has also been appraised. Considering the complications associated with the shunt-based surgical operations, consistent monitoring of shunting via neuroimaging techniques hold greater clinical significance. Despite having extensive applicability of MRI and CT scan, these conventional neuroimaging techniques are associated with misdiagnosis or several health risks to patients. Recent advances in MRI (i.e., Sagittal-MRI, coronal-MRI, Time-SLIP (time-spatial-labeling-inversion-pulse), PC-MRI and diffusion-tensor-imaging (DTI)) have shown promising applicability in the diagnosis of NPH. Having associated with several adverse effects with surgical interventions, non-invasive approaches (pharmacological agents) have earned greater interest of scientists, medical professional, and healthcare providers. Amongst pharmacological agents, diuretics, isosorbide, osmotic agents, carbonic anhydrase inhibitors, glucocorticoids, NSAIDs, digoxin, and gold-198 have been employed for the management of NPH and prevention of secondary sensory/intellectual complications. Employment of rational diagnostic tool and therapeutic modalities avoids misleading diagnosis and sophisticated management of hydrocephalus by efficient reduction of Cerebrospinal Fluid (CSF) production, reduction of fibrotic and inflammatory cascades secondary to meningitis and hemorrhage, and protection of brain from further deterioration.

Development of the MRI Flow Phantom System Focused on Low Speed Flows in Fluid Machinery

At present, magnetic resonance imaging (MRI), which is one of the noninvasive diagnostic imaging techniques for medical use, has been applied to industrial product inspection. In this study, a hydraulic model test system, called the “flow phantom system,” which can generate steady flow and oscillating flow for time-resolved MRI, was developed to aid optimum design of fluid machinery. Simple flow phantoms are tested under laminar flow or oscillating flow to evaluate the validity and effectiveness of the proposed system. In this article, the test results of double cylindrical pipe flow, elbow pipe flow, cylindrical valve flow, and jet pump flow, which are often seen in fluid machines, are tested using the 2D time-spatial labeling inversion pulse (Time-SLIP) method, which can track a labeled water mass and visualize it using two-dimensional images. MRI-detected flow patterns were compared with particle image velocimetry (PIV) or numerical simulation.

A new MRI tag-based method to non-invasively visualize cerebrospinal fluid flow.

Abnormal cerebrospinal fluid (CSF) dynamics can produce a number of significant clinical problems to include hydrocephalus, loculated areas within the ventricles or subarachnoid spaces as well as impairment of normal CSF movement between the cranial and spinal compartments that can result in a cerebellar ectopia and hydrosyringomyelia. Thus, assessing the patency of fluid flow between adjacent CSF compartments non-invasively by magnetic resonance imaging (MRI) has definite clinical value. Our objective was to demonstrate that a novel tag-based CSF imaging methodology offers improved contrast when compared with a commercially available application. In a prospective study, ten normal healthy adult subjects were examined on 3T magnets with time-spatial labeling inversion pulse (Time-SLIP) and a new tag-based flow technique-time static tagging and mono-contrast preservation (Time-STAMP). The image contrast was calculated for dark-untagged CSF and bright-flowing CSF. We tested the results with the D'Agostino and Pearson normality test and Friedman's test with Dunn's multiple comparison correction for significance. Separately 96 pediatric patients were evaluated using the Time-STAMP method. In healthy adults, contrasts were consistently higher with Time-STAMP than Time-SLIP (p < 0.0001, in all ROI comparisons). The contrast between untagged CSF and flowing tagged CSF improved by 15 to 34%. In both healthy adults and pediatric patients, CSF flow between adjacent fluid compartments was demonstrated. Time-STAMP provided images with higher contrast than Time-SLIP, without diminishing the ability to visualize qualitative CSF movement and between adjacent fluid compartments.

Novel Assessment of Cerebrospinal Fluid Dynamics by Time-Spatial Labeling Inversion Pulse Magnetic Resonance Imaging in Patients with Chiari Malformation Type I.

We investigated cerebrospinal fluid (CSF) dynamics at the craniocervical junction (CCJ) using Time-SLIP magnetic resonance imaging to demonstrate the significance of ventral and dorsal combined CSF dynamics in assessing CSF flow disturbance in patients with Chiari malformation type I. Fifteen examinations were performed in 9 cases of CM-I (3 female patients; mean age, 24.7 years; age range, 11-46 years) before or after craniocervical decompression. The longitudinal maximum movement of the caudal edge of tagged midsagittal CSF at the CCJ was measured as length of motion (LOM), and total on the ventral and dorsal sides was defined as total LOM. In 8 conditions, where it was concluded that no craniocervical decompression was necessary or where symptoms improved following craniocervical decompression based on the clinical symptoms, total LOM was 49.8 ± 13.1 mm. In contrast, in the 7 cases where craniocervical decompression was mandatory, total LOM was 23.2 ± 9.2 mm. Significant differences were identified between the 2 groups. Total LOM <35.0 mm resulted to indicate the insufficiency of CSF dynamics, because it corresponded to the necessity of craniocervical decompression based on patients' symptoms. Time-SLIP MRI enabled clinicians to use novel dynamic indices, such as CSF motions, in addition to the conventional findings acquired by MRI. In particular, it was essential to examine combined ventral and dorsal CSF dynamics in assessing CSF patency at the CCJ in patients with CM-I.

Left Gastric Vein Visualization with Hepatopetal Flow Information in Healthy Subjects Using Non-Contrast-Enhanced Magnetic Resonance Angiography with Balanced Steady-State Free-Precession Sequence and Time-Spatial Labeling Inversion Pulse.

ObjectiveTo selectively visualize the left gastric vein (LGV) with hepatopetal flow information by non-contrast-enhanced magnetic resonance angiography under a hypothesis that change in the LGV flow direction can predict the development of esophageal varices; and to optimize the acquisition protocol in healthy subjects.Materials and MethodsRespiratory-gated three-dimensional balanced steady-state free-precession scans were conducted on 31 healthy subjects using two methods (A and B) for visualizing the LGV with hepatopetal flow. In method A, two time-spatial labeling inversion pulses (Time-SLIP) were placed on the whole abdomen and the area from the gastric fornix to the upper body, excluding the LGV area. In method B, nonselective inversion recovery pulse was used and one Time-SLIP was placed on the esophagogastric junction. The detectability and consistency of LGV were evaluated using the two methods and ultrasonography (US).ResultsLeft gastric veins by method A, B, and US were detected in 30 (97%), 24 (77%), and 23 (74%) subjects, respectively. LGV flow by US was hepatopetal in 22 subjects and stagnant in one subject. All hepatopetal LGVs by US coincided with the visualized vessels in both methods. One subject with non-visualized LGV in method A showed stagnant LGV by US.ConclusionHepatopetal LGV could be selectively visualized by method A in healthy subjects.

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.

Novel Application of Time-Spatial Labeling Inversion Pulse Magnetic Resonance Imaging for Diagnosis of External Hydrocephalus.

Although a subdural fluid collection frequently is observed, diagnostic methods that differentiate between the subdural collection caused by external hydrocephalus and that caused by subdural hygroma have not been established. Here, we report a case of external hydrocephalus caused by Gliadel-induced eosinophilic meningitis that has been previously reported in only 1 case and can be diagnosed by time-spatial labeling inversion pulse magnetic resonance imaging (time-SLIP MRI). A tumor located in the left temporal was detected incidentally in an 81-year-old man by examination of a head injury. The tumor was surgically resected and diagnosed as a high-grade glioma during the surgery; Gliadel wafers subsequently were implanted. Three weeks after the resection, the patient showed disturbed consciousness, and computed tomography revealed a subdural fluid collection. The out-flow of cerebrospinal through the resection cavity was detected by time-SLIP MRI. Cerebrospinal tests indicated high white blood cell counts and high protein levels, with more than 90% of the white blood cell count comprising eosinophils. Therefore, we suspected that the subdural fluid collection was caused by external hydrocephalus because of Gliadel-induced eosinophilic meningitis. We surgically removed the Gliadel wafers and subsequently performed a surgery to insert a ventriculoperitoneal shunt. Histologic examination indicated eosinophilic accumulation around the Gliadel wafers. The patient's symptoms improved after the insertion of a ventriculoperitoneal shunt. In the present case, time-SLIP MRI was a useful and noninvasive method for diagnosing external hydrocephalus which was caused by eosinophilic meningitis because of Gliadel-induced eosinophilic meningitis.