Cerebrospinal Fluid Signal Intensity Research Articles

Comparison of Short-Tau Inversion Recovery With Short-Tau Inversion Recovery-Slice Encoding for Metal Artifact Correction for Spine Imaging at 1.5 T in the Setting of Metallic Implants.

To compare the image quality of short-tau inversion recovery (STIR) and the STIR-slice encoding for metal artifact correction (SEMAC) sequence for postsurgery spine magnetic resonance imaging (MRI). Twenty-nine patients with metallic spinal implants who underwent spinal 1.5 T MRI with STIR and STIR-SEMAC sequences between July 2016 and November 2020 were retrospectively enrolled. Qualitative assessments were performed using 5-point scales; higher scores indicated better image quality. For screw metal artifact analysis, scores were obtained for artifacts on vertebral bodies and neural foramina, screw artifact widths, and bone marrow signal intensities. For patient-based analysis, scores were obtained for imaging quality and fat suppression quality, signal intensity, and cerebrospinal fluid noise. A paired t test was performed for statistical analyses. We analyzed 163 screws in 29 patients. In the screw metal artifact analysis, the vertebral body and neural foramen scores were significantly higher for the STIR-SEMAC images than for the STIR (all P < 0.001). The artifact width in the STIR-SEMAC images (9.8 ± 3.4 mm) was significantly smaller than that in the STIR images (16.0 ± 4.7 mm, P < 0.001). In patient-based analysis, the fat suppression and imaging quality scores were significantly higher for the STIR-SEMAC images than for the STIR images (all P < 0.001). The cerebrospinal fluid signal intensity, noise, and signal-to-noise ratios were significantly higher for the STIR images (all P < 0.005). Short-tau inversion recovery-SEMAC sequences provide good metallic artifact reduction and fat suppression for postsurgery spine 1.5 T MRI.

Clinicoradiologic Characteristics of Intradural Extramedullary Conventional Spinal Ependymoma.

Distinguishing intradural extramedullary (IDEM) spinal ependymoma from myxopapillary ependymoma is challenging due to the location of IDEM spinal ependymoma. This study aimed to investigate the utility of clinical and MR imaging features for differentiating between IDEM spinal and myxopapillary ependymomas. We compared tumor size, longitudinal/axial location, enhancement degree/pattern, tumor margin, signal intensity (SI) of the tumor on T2-weighted images and T1-weighted image (T1WI), increased cerebrospinal fluid (CSF) SI caudal to the tumor on T1WI, and CSF dissemination of pathologically confirmed 12 IDEM spinal and 10 myxopapillary ependymomas. Furthermore, classification and regression tree (CART) was performed to identify the clinical and MR features for differentiating between IDEM spinal and myxopapillary ependymomas. Patients with IDEM spinal ependymomas were older than those with myxopapillary ependymomas (48 years vs. 29.5 years, p < 0.05). A high SI of the tumor on T1W1 was more frequently observed in IDEM spinal ependymomas than in myxopapillary ependymomas (p = 0.02). Conversely, myxopapillary ependymomas show CSF dissemination. Increased CSF SI caudal to the tumor on T1WI was observed more frequently in myxopapillary ependymomas than in IDEM spinal ependymomas (p < 0.05). Dissemination to the CSF space and increased CSF SI caudal to the tumor on T1WI were the most important variables in CART analysis. Clinical and radiological variables may help differentiate between IDEM spinal and myxopapillary ependymomas.

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

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. 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. 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). 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.

MRI-Based Score for Assessment of Bone Mineral Density in Operative Spine Patients.

Retrospective comparison. The aim was to determine whether a previously developed magnetic resonance imaging (MRI)-derived bone mineral density (BMD) scoring system can differentiate between healthy and osteoporotic vertebrae and to validate this scoring system against quantitative computed tomography measurements. BMD is an important preoperative consideration in spine surgery. Techniques to measure BMD are subject to falsely elevated values in the setting of spondylosis (dual-energy X-ray absorptiometry) or require significant exposure to radiation [quantitative computed tomography (QCT)]. Previous studies have shown that MRI may be utilized to measure bone quality using changes in the bone marrow signal observed on T1-weighted MRIs. Retrospective study of patients who underwent operative lumbar procedures at a single tertiary institution between 2016 and 2021 (n=61). Vertebral bone quality (VBQ) scores were measured by dividing the median signal intensities of L1-L4 by the signal intensity of cerebrospinal fluid on noncontrast T1W MRI. Demographic data, comorbidities, VBQ scores, and QCT-derived T scores and BMD of the lumbar spine were compared between healthy ( T score ≥-1; n=21), osteopenic (-2.5 < T score < -1; n=21), and osteoporotic ( T score ≤-2.5; n=19) cohorts using analysis of variance with post hoc Tukey test. Linear regression and receiver operating characteristic curve analyses were performed to assess the predictive value of VBQ scores. Pearson correlation test was used to evaluate the association between VBQ scores and QCT-derived measurements. VBQ differentiated between healthy and osteoporotic groups ( P =0.009). Receiver operating characteristic curve analysis revealed that a greater VBQ score was associated with presence of osteoporosis (area under the curve=0.754, P =0.006). Cutoff VBQ for osteoporosis was 2.6 (Youden index 0.484; sensitivity: 58%; specificity: 90%). VBQ scores weakly correlated with QCT-derived BMD ( P =0.03, r =-0.27) and T scores ( P =0.04, r =-0.26). This study attempted to further validate a previously developed MRI-based BMD scoring system against QCT-derived measurements. VBQ score was found to be a significant predictor of osteoporosis and could differentiate between healthy and osteoporotic vertebrae.

Cystic Neuronal Necrosis of Posterior Thalami in Neonatal Hypoxic Ischemic Encephalopathy: A Case Report of an Unusual Radiological Finding

Background: Neonatal hypoxic ischemic encephalopathy (HIE) occurs as a result of any event that causes hypoxia and hypoperfusion to the developing neonatal brain. In addition to being a major cause of neonatal mortality, it is also associated with significant long-term neurological deficits. Multicystic encephalomalacia is a sequelae to global hypoxic ischemic injury which is characterized by cortical atrophy, basal ganglia/thalamic atrophy, and cystic necrosis of cerebral white matter. In this report, we present an unusual finding of cystic necrosis of thalami in HIE. Case Presentation: We present the case of a term neonate with a history of prolonged labor and meconium aspiration who developed HIE stage III. The neonate initially required ventilator support and was gradually weaned off but was reintubated in view of neonatal sepsis. Magnetic resonance imaging done on day 23 revealed diffuse cortical and white matter atrophy, signal intensity alteration in basal ganglia and thalami, and multiple well-defined areas of cerebrospinal fluid signal intensity in the white matter, consistent with multicystic encephalomalacia. An additional unusual finding was cystic necrosis, symmetrically involving bilateral posterior thalami. Conclusion: According to our observation, severe prolonged hypoxic ischemic insult does not only result in central gray matter atrophy but can also cause cystic neuronal necrosis of the same.

ISSLS prize in clinical science 2022: accelerated disc degeneration after pubertal growth spurt differentiates adults with low back pain from their asymptomatic peers

PurposeIn this prospective observational cohort study, the development of lumbar intervertebral discs (LIVD) on magnetic resonance imaging (MRI) was investigated from childhood to adulthood with emphasis on the possible association of disc degeneration (DD) to low back pain (LBP).MethodsIn 2021, 89 subjects who were enrolled in 1994 in a longitudinal study with lumbar spine MRI at ages 8, 11 and 18 were invited to participate in a long-term follow-up comprising a clinical examination, selected patient-reported outcome measures and a lumbar spine MRI. We assessed all MRIs (three lowest LIVDs) with the Pfirrmann summary score, and the ratio of signal intensity of nucleus pulposus to signal intensity of cerebrospinal fluid (SINDL). We further analyzed whether disc changes at any age were associated with self-reported LBP at age 34.ResultsOf the 48 subjects in the follow-up, 35 reported LBP at age 34. The Pfirrmann summary score significantly increased with age (p < 0.001). Subjects reporting LBP at age 34 demonstrated statistically significantly higher summary scores at age 18 and 34 compared to asymptomatic subjects (p = 0.004 at age 18, and p = 0.039 at age 34). SINDL significantly decreased with age (p < 0.001 for all levels separately), but no significant differences between subjects with or without LBP at age 34 were noticed.ConclusionSubjects with LBP at age 34 had more widespread or severe DD already at age 18 compared to those without LBP.

Can routine MRI spine T1 sequences be used for prediction of decreased bone density?

Bone marrow signal is ideally evaluated with magnetic resonance imaging (MRI) due to its high tissue contrast. While advanced MRI quantitative methods can be used for estimating bone density, there are no readily available parameters on routine clinical MRI sequences of the lumbar spine. To evaluate whether T1 signal intensity (SI) ratio of lumbar vertebral body (VB)/cerebrospinal fluid (CSF) may predict decreased bone density. A retrospective study was conducted. After use of inclusion/exclusion criteria, 36 patients who had an MRI scan of the lumbar spine and a DEXA scan performed as a part of annual health visit were selected. T1 SI of the lumbar vertebral bodies and adjacent CSF were recorded. Ratio of T1 SI of L1-L4 (VB)/CSF was calculated. The corresponding bone-density values on DEXA scan measured as g/cm2 were obtained. Pearson's r correlation statistic was used to determine the correlation between these variables. T1 VB/T1 CSF SI ratio was between 1.308 and 2.927 (mean = 2.028). Mean T1 SI value of vertebral bodies (L1-L4) was 264.9 and mean CSF SI value was 131.9. Bone density in g/cm2 was between 0.851 and 1.398 (mean = 1.081). Pearson correlation coefficient was r = -0.619 (P=0.0001), which shows a negative moderate correlation between the T1 VB/T1 CSF SI ratio and bone density. A high T1 VB/T1 CSF SI ratio on routine MRI sequences may indicate decreased bone density. This ratio may be of substantial benefit in unsuspected osteoporosis/osteopenia on routine MRI lumbar spine imaging.

Quantitative magnetic resonance imaging for evaluating of the cerebrospinal fluid kinetics with 17O-labeled water tracer: A preliminary report

The aim of this study was to evaluate the feasibility of kinetic analysis of cerebrospinal fluid (CSF) using 17O-labeled water tracer. Four subjects (two idiopathic normal pressure hydrocephalus (iNPH) and two possible AD dementia patients) were prospectively included. Injectable formulation of 17O-labeled water containing 10 mol% of H217O (PSO17), was intrathecally administered to the subjects with the lateral decubitus position between the 3rd and 4th lumbar vertebrae. MRI acquisitions were performed in four-time points, before PSO17 administration, 1, 8, and 24 h after PSO17 administration. The 3-dimensional fast spin echo sequence was used. After image registration for all four-time points data, polygonal regions of interest (ROIs) were set in the 14 regions to obtain the signal intensity of CSF. Each signal intensity within the ROI was converted to 17O concentration [%]. The peak concentration at one hour after administration, the slope of concentration changes after PSO17 administration [%/s], and the root mean square error (RMSE) for evaluating the performance of a fitting were calculated. There was no significant difference in peak concentration between the iNPH and AD group. The slope in the AD group (−2.25 ± 1.62 × 10−3 [%/h]) was significantly smaller than in the iNPH group (−1.21 ± 2.31 × 10−3 [%/h]), which suggests the speed of CSF clearance in the iNPH group was slower than AD group. The RMSE indicating the fit to the concentration change in the AD group (4.86 ± 4.74 × 10−3) was also significantly smaller than in the iNPH group (8.64 ± 7.56 × 10−3). The kinetic evaluation of CSF using 17O-labeled water was feasible, and this preliminary study suggests that the differentiation of iNPH and possible AD dementia can be achieved using this method.

Letter: Cranioplasty Reverses Dysfunction of the Solutes Distribution in the Brain Parenchyma After Decompressive Craniectomy

Letter: Cranioplasty Reverses Dysfunction of the Solutes Distribution in the Brain Parenchyma After Decompressive Craniectomy

Optimization of the refocusing flip angle in the characterization of cerebrospinal fluid dynamics using multi-spin echo acquisition cine imaging (MUSACI)

PurposeMulti-spin echo acquisition cine imaging (MUSACI) is a method used for cerebrospinal fluid (CSF) dynamics imaging based on the proton phase dispersion and flow void using 3D multi-spin echo imaging. In a previous study, the refocusing flip angle of MUSACI was set at a constant 80°. We conducted the present study to investigate the preservation the CSF signal intensity even in a long echo train and improve the ability to visualize CSF movement by modifying the refocusing flip angle in MUSACI. MethodsThe MUSACI images were acquired in 10 healthy volunteers (7 men and 3 women; age range 24–44 years; mean age 29.4 ± 6.2 years) with a 3.0 Tesla MR scanner. Five refocusing flip angle sets were applied: constant 30°, constant 50°, constant 80°, pseudo-steady state (PSS) 50°–70°–100° (PSS50°), and PSS80°–100°–130° (PSS80°). In all sequences, the in-plane spatial resolution was 0.58 × 0.58 mm2, and the CSF movement for one heartbeat was drawn at 80-msec intervals. The signal intensity (SI) of CSF in the lateral ventricle, the foramen of Monro, the third ventricle, the fourth ventricle, and the pons was measured on MUSACI. Pearson's correlation coefficient was calculated between the CSF SI and effective echo time (TE; TEeff) in the lateral ventricle. ResultsBoth antegrade and retrograde CSF movements on the midsagittal MUSACI images and the retrograde CSF movement in the foramen of Monro was observed in all sequences with the constant flip angles. A strong reverse correlation between the CSF SI in the lateral ventricle and TEeff values was observed with constant 30° (r = −0.96, p < 0.01), constant 50° (r = −0.97, p < 0.01) and constant 80° (r = −0.88, p < 0.01). A weak positive correlation was observed with PSS50° (r = 0.28, p = 0.43), and a moderate reverse correlation was observed at PSS80° (r = −0.60, p = 0.07). The SI values of the foramen of Monro, the third ventricle, and the fourth ventricle were significantly lower than that of the lateral ventricle, and those values were higher than that of the pons in both the constant 80° sequence and the PSS 50° sequence. ConclusionPSS50° could be the optimal flip angle scheme for MUSACI, because the SI changes due to CSF movement and the SI preservation due to a long echo train were large due to the use of the refocusing flip angle method.

A novel MRI-based score assessing trabecular bone quality to predict vertebral compression fractures in patients with spinal metastasis.

Vertebral compression fractures (VCFs) in patients with spinal metastasis can lead to destabilization and often carry a high risk profile. It is therefore important to have tools that enable providers to predict the occurrence of new VCFs. The most widely used tool for bone quality assessment, dual-energy x-ray absorptiometry (DXA), is not often available at a patient's initial presentation and has limited sensitivity. While the Spinal Instability Neoplastic Score (SINS) has been associated with VCFs, it does not take patients' baseline bone quality into consideration. To address this, the authors sought to develop an MRI-based scoring system to estimate trabecular vertebral bone quality (VBQ) and to assess this system's ability to predict the occurrence of new VCFs in patients with spinal metastasis. Cases of adult patients with a diagnosis of spinal metastasis, who had undergone stereotactic body radiation therapy (SBRT) to the spine or neurosurgical intervention at a single institution between 2012 and 2019, were retrospectively reviewed. The novel VBQ score was calculated for each patient by dividing the median signal intensity of the L1-4 vertebral bodies by the signal intensity of cerebrospinal fluid (CSF). Multivariable logistic regression analysis was used to identify associations of demographic, clinical, and radiological data with new VCFs. Among the 105 patients included in this study, 56 patients received a diagnosis of a new VCF and 49 did not. On univariable analysis, the factors associated with new VCFs were smoking status, steroid use longer than 3 months, the SINS, and the novel scoring system-the VBQ score. On multivariable analysis, only the SINS and VBQ score were significant predictors of new VCFs and, when combined, had a predictive accuracy of 89%. As a measure of bone quality, the novel VBQ score significantly predicted the occurrence of new VCFs in patients with spinal metastases independent of the SINS. This suggests that baseline bone quality is a crucial factor that requires assessment when evaluating these patients' conditions and that the VBQ score is a novel and simple MRI-based measure to accomplish this.

Preliminary observation on the changes of T(1) weighted signal of globus pallidus after multiple intravenous injection of linear gadolinium contrast agent

Objective: To explore the changes in signal intensity (SI) ratios of globus pallidus (GP) on unenhanced T(1)-weighted(T(1)WI)magnetic resonance imaging (MRI) scans between the first and last MRI using the linear gadolinium-based contrast agent (GBCAs) intravenously. Methods: Clinical and imaging data of 114 patients who underwent at least 4 consecutive enhanced MRI examinations at the Affiliated Hospital of Xuzhou Medical University between January 2016 and April 2018 were analyzed. The SI ratio of GP, thalamus and cerebrospinal fluid (CSF) were measured on unenhanced T(1)WI. The GP to thalamus SI ratio was calculated by dividing the SI in the GP by that in the thalamus, and so was the GP to CSF SI ratio. The difference of SI ratio in the same patient was analyzed by nonparametric tests, linear regression analysis was used to analyze clinical factors. Results: The SI ratio of GP-to-thalamus and GP-to-CSF after multiple enhancement were higher than before, and the difference was statistically significant. The SI ratio of GP-to-thalamus and GP-to-CSF before and after repeated contrast-enhanced were 1.036(1.010, 1.075), 1.104(1.074, 1.168); 4.215(3.590, 5.614), 5.409(4.213, 6.502), all P<0.01. The SI ratio differences showed a significant positive correlation with the number of enhanced examination(pons:b=0.023, P<0.01,CSF:b=0.279,P=0.034), and a significant negative correlation with the interval (pons: b=-0.002,P< 0.01, CSF: b=-0.023, P=0.039). There was no correlation with other clinical factors (all P>0.05). Conclusions: There is an increase in SI in the GP after serial injections of linear GBCAs, and there is a positive correlation with the times of enhanced examination, and a negative correlation with time interval.

Optic Nerve Sheath Meningocele With Optic Disc Pit: A Rare Finding

A 13-year-old girl presented with complaints of painless, progressive protrusion of her left eye for last 2 years with mild visual blurring. She had 4 mm proptosis in her left eye with relative afferent pupillary defect. Visual acuity in the right eye was 20/20 and in the left eye was 20/25 on Snellens acuity testing. MRI revealed a well-circumscribed, cerebrospinal fluid signal intensity cystic lesion medial to the optic nerve (Figs. 1 and 2). Optic nerve sheath meningocele is a primary enlargement of the optic nerve sheath. Optic nerve sheath meningocele can present with progressive hyperopia and choroidal folds in middle-aged males. Proposed theories of pathophysiology of optic nerve sheath meningocele are either congenital narrowing of the optic/cranio-orbital junction causing cerebrospinal fluid accumulation in the perioptic subarachnoid space or a difference in osmotic gradient between the cerebral and perioptic subarachnoid space. The radiologic examination of choice is MRI with fat suppression which shows enlargement of the optic nerve sheath isointense with cerebrospinal fluid. There has been no consensus about management for these patients. Patients with progressive visual loss have been treated by optic nerve sheath fenestration leading to halting of the progression. Supplementary management with acetazolamide, especially in patients with associated increased intracranial pressure, is advisable. Our patient has no such complaints and is under periodic review.FIG. 1.: Clinical and investigational pictures of patient of optic nerve sheath meningocele with optic disc pit. Upper right Fundus photograph of left eye showing the posterior pole with a nasal optic disc pit with RNFL edema and radiating choroidal folds. Left Humphrey Visual Field of the left eye. Lower right Worm’s view external photograph of the patient.FIG. 2.: Clinical and investigational pictures of patient of optic nerve sheath meningocele with optic disc pit. A, T1-weighted image of axial MRI. B: T2-weighted fat-suppressed image showing intraconal cystic lesion medial to the optic nerve with similar signal intensity as cerebrospinal fluid. C, T2-weighted sagittal MRI.

Optic Nerve Sheath Meningocele With Optic Disc Pit

A 13-year-old girl presented with complaints of painless, progressive protrusion of her left eye for last 2 years with mild visual blurring. She had 4 mm proptosis in her left eye with relative afferent pupillary defect. Visual acuity in the right eye was 20/20 and in the left eye was 20/25 on Snellens acuity testing. MRI revealed a well-circumscribed, cerebrospinal fluid signal intensity cystic lesion medial to the optic nerve (Figs. 1 and 2). Optic nerve sheath meningocele is a primary enlargement of the optic nerve sheath. Optic nerve sheath meningocele can present with progressive hyperopia and choroidal folds in middle-aged males. Proposed theories of pathophysiology of optic nerve sheath meningocele are either congenital narrowing of the optic/cranio-orbital junction causing cerebrospinal fluid accumulation in the perioptic subarachnoid space or a difference in osmotic gradient between the cerebral and perioptic subarachnoid space. The radiologic examination of choice is MRI with fat suppression which shows enlargement of the optic nerve sheath isointense with cerebrospinal fluid. There has been no consensus about management for these patients. Patients with progressive visual loss have been treated by optic nerve sheath fenestration leading to halting of the progression. Supplementary management with acetazolamide, especially in patients with associated increased intracranial pressure, is advisable. Our patient has no such complaints and is under periodic review.FIG. 1.: Clinical and investigational pictures of patient of optic nerve sheath meningocele with optic disc pit. Upper right Fundus photograph of left eye showing the posterior pole with a nasal optic disc pit with RNFL edema and radiating choroidal folds. Left Humphrey Visual Field of the left eye. Lower right Worm’s view external photograph of the patient.FIG. 2.: Clinical and investigational pictures of patient of optic nerve sheath meningocele with optic disc pit. A, T1-weighted image of axial MRI. B: T2-weighted fat-suppressed image showing intraconal cystic lesion medial to the optic nerve with similar signal intensity as cerebrospinal fluid. C, T2-weighted sagittal MRI.

Increased signal intensity in the dentate nucleus on unenhanced T1-weighted MR images after multiple gadolinium-based contrast material administrations: a preliminary study

Objective To compare changes in signal intensity (SI) of the dentate nucleus (DN), pons and cerebrospinal fluid (CSF) on unenhanced T1-weighted magnetic resonance imaging (MRI) scans after multiple administrations of the linear gadolinium-based contrast agent. Methods Clinical and imaging data of forty-nine patients who underwent at least 4 consecutive enhanced MRI examinations were analyzed retrospectively (unenhanced T1-weighted MRI scans were performed before and after consecutive enhanced MRI examinations). The mean SI of DN, pons and CSF were measured on unenhanced T1-weighted images. The SI ratio of DN to pons was calculated by dividing the SI in the DN by that in the pons, and so was The DN to CSF SI ratio. The difference of SI ratio of DN-to-pons and DN-to-CSF in the same patient before and after repeated contrast-enhanced T1WI were analyzed by paired-samples t tests. Linear regression analysis was used to analyze whether the SI ratios of DN-to-pons, DN-to-CSF were correlated with any clinical factor. Results The SI ratios of DN-to-pons and DN-to-CSF after multiple contrast administrations were higher than those before enhancement, and the differences were statistically significant. The SI ratios of DN-to-pons and DN-to-CSF before and after repeated contrast enhancement were 0.98±0.62, 1.05±0.54; 3.89±0.94, 4.97±1.61 (t=-8.494, -4.526, P 0.05). Conclusions This study indicates that serial injections of linear gadolinium-based contrast agent may lead to an increase in SI in the DN. Key words: Gadolinium; Dentate nucleus; Magnetic resonance imaging

Can low b value diffusion weighted imaging evaluate the character of cerebrospinal fluid dynamics?

We aimed to investigate whether low b value diffusion-weighted imaging (DWI) can show the change of cerebrospinal fluid (CSF) dynamics. The subjects of this retrospective study consisted of patients with ventricular dilatation (n = 50) and controls (n = 50). The CSF signal intensity on the b = 500s/mm2 DWI was evaluated by a scoring method in the lateral, 3rd and 4th ventricles, the cerebral sulci and the Sylvian fissure. The signal void findings adjacent to the septum pellucidum were also evaluated. The CSF signal intensities were significantly less in lateral ventricle and 3rd ventricle of the ventricular dilatation subjects. In controls, the score for the signal void in the Sylvian fissure showed a significant positive correlation with age. However, other areas did not show a significant correlation with age. The appearance of the characteristic signal void adjacent to the septum pellucidum showed a significant correlation with ventricular dilatation. Our current study suggests that the CSF signal intensity on the b = 500s/mm2 DWI may show the changes in CSF dynamics and might be useful to evaluate the overlook of CSF dynamics.

Voxelwise computed diffusion-weighted imaging for the detection of cytotoxic oedema in brain imaging: a pilot study.

Aim To evaluate voxelwise computed diffusion-weighted imaging (vcDWI) for the detection of cytotoxic oedema in brain imaging and to quantify the benefit of lesion contrast in comparison to standard b = 1000 s/mm2 by the example of acute ischaemic stroke. Materials and methods A retrospective evaluation of 66 patients (63 ± 15.9 years) suspected for acute ischaemic stroke who received diffusion-weighted magnetic resonance imaging and fluid-attenuated inversion recovery sequence. A neuroradiologist evaluated all examinations for acute ischaemic stroke based on diffusion-weighted imaging, the apparent diffusion coefficient and fluid-attenuated inversion recovery (reference standard) and 6 weeks later the vcDWI in a randomised manner. Time of analysis was noted. Signal intensities were acquired in lesions, in healthy tissue as well as in the cerebrospinal fluid. Contrast ratios and coefficients of variation were computed. Results A total of 218 lesions was found in 46/66 patients. vcDWI identified all patients and lesions correctly. The median evaluation time was 36 seconds (4-126 s) for the vcDWI and 44 seconds (9-186 s; P < 0.001) for the diffusion-weighted imaging/apparent diffusion coefficient reading. The contrast ratio in vcDWI (mean value 2.57, range 1.73-4.11) was higher than in b = 1000 s/mm2 (2.33, 0.83-3.85, P = 0.03) and the apparent diffusion coefficient map (1.83, 1.00-3.00, P < 0.001), respectively. Coefficients of variation in lesions and tissue did not differ significantly between vcDWI and b = 1000 s/mm2 ( P = 0.81/ P = 0.26). The signal intensity of cerebrospinal fluid was lower in vcDWI than in b = 1000 mm2/s (0.08 and 34.8, P < 0.001). Conclusion It could be shown that vcDWI has the potential to accelerate the detection of diffusion-restricted lesions in neuroimaging by improving the contrast ratios and reducing the T2 shine-through effect in comparison to standard diffusion-weighted imaging in brain imaging.

Neuroendoscopic treatment of multiple intracranial arachnoid cysts: a case report

BackgroundMultiple arachnoid cysts are very rare within the central nervous system. The cysts will sometimes increase in size with age, lead to the mass effect or cerebrospinal fluid (CSF) flow obstruction, and cause some symptoms, which requires the surgery intervention.Case presentationA 35-year-old female was admitted to our hospital with some symptoms related to hydrocephalus for 1 month. Brain magnetic resonance imaging (MRI) revealed well-marginated cystic lesions with CSF signal intensity in the ventricular and cisternal systems, bilateral temporal lobes, and left occipital lobe. Cine phase-contrast MRI showed the aqueduct of sylvius was blocked by the cyst in the quadrigeminal cistern. We employed endoscopic ventriculocystostomy and septostomy to create the communication of the cyst with ventricular and cistern system. As a result, the patient’s symptoms were relieved.ConclusionsEndoscopic management can be an effective way for treating intracranial multiple arachnoid cysts, which is the first report of this kind. We hope that this report could help improve the management of intracranial arachnoid cysts with the neuroendoscopic technology.

Double inversion recovery imaging of the brain: deriving the most relevant sequence through real images.

We propose a practical method for setting the optimal inversion times (TI) for double inversion recovery (DIR) sequences. Our method used the measurement of signal intensity (SI) from real images to set the optimal TI for white-matter (WM) and gray-matter (GM)-attenuated inversion recovery (WAIR and GAIR, respectively) images.3D-DIR images of healthy volunteers were obtained on 1.5- and 3.0-T magnetic resonance (MR) scanners and the SIs of GM, WM, and cerebrospinal fluid (CSF) were evaluated on real images. We found TI2s at which the SI of WM or GM was null. Then, we found TI1+2 (=TI1+TI2) at which the SI of CSF was null. We defined the two TIs as optimal TIs. We assessed the utility of these TIs with additional volunteers and patients, and similar images were obtained with the determined TIs. Optimal TIs for DIR images could be efficiently determined using this method.

Cerebrospinal Fluid Clearance in Alzheimer Disease Measured with Dynamic PET.

Evidence supporting the hypothesis that reduced cerebrospinal fluid (CSF) clearance is involved in the pathophysiology of Alzheimer disease (AD) comes primarily from rodent models. However, unlike rodents, in which predominant extracranial CSF egress is via olfactory nerves traversing the cribriform plate, human CSF clearance pathways are not well characterized. Dynamic PET with 18F-THK5117, a tracer for tau pathology, was used to estimate the ventricular CSF time-activity as a biomarker for CSF clearance. We tested 3 hypotheses: extracranial CSF is detected at the superior turbinates; CSF clearance is reduced in AD; and CSF clearance is inversely associated with amyloid deposition. Methods: Fifteen subjects, 8 with AD and 7 normal control volunteers, were examined with 18F-THK5117. Ten subjects additionally underwent 11C-Pittsburgh compound B (11C-PiB) PET scanning, and 8 were 11C-PiB-positive. Ventricular time-activity curves of 18F-THK5117 were used to identify highly correlated time-activity curves from extracranial voxels. Results: For all subjects, the greatest density of CSF-positive extracranial voxels was in the nasal turbinates. Tracer concentration analyses validated the superior nasal turbinate CSF signal intensity. AD patients showed ventricular tracer clearance reduced by 23% and 66% fewer superior turbinate CSF egress sites. Ventricular CSF clearance was inversely associated with amyloid deposition. Conclusion: The human nasal turbinate is part of the CSF clearance system. Lateral ventricle and superior nasal turbinate CSF clearance abnormalities are found in AD. Ventricular CSF clearance reductions are associated with increased brain amyloid depositions. These data suggest that PET-measured CSF clearance is a biomarker of potential interest in AD and other neurodegenerative diseases.