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BACKGROUND/HYPOTHESIS: Divergent thinking is an important measurable component of creativity. This study tested the postulate that divergent thinking depends on large distributed inter- and intra-hemispheric networks. Although preliminary evidence supports increased brain connectivity during divergent thinking, the neural correlates of this characteristic have not been entirely specified. It was predicted that visuospatial divergent thinking would correlate with right hemisphere white matter volume (WMV) and with the size of the corpus callosum (CC). METHODS: Volumetric magnetic resonance imaging (MRI) analyses and the Torrance Tests of Creative Thinking (TTCT) were completed among 21 normal right-handed adult males. RESULTS: TTCT scores correlated negatively with the size of the CC and were not correlated with right or, incidentally, left WMV. CONCLUSIONS: Although these results were not predicted, perhaps, as suggested by Bogen and Bogen (1988), decreased callosal connectivity enhances hemispheric specialization, which benefits the incubation of ideas that are critical for the divergent-thinking component of creativity, and it is the momentary inhibition of this hemispheric independence that accounts for the illumination that is part of the innovative stage of creativity. Alternatively, decreased CC size may reflect more selective developmental pruning, thereby facilitating efficient functional connectivity. [ABSTRACT FROM AUTHOR]

Abstract Background Our purpose was to study the association between the intracranial atherosclerosis as measured by cavernous carotid artery calcification (ICAC) observed on head CT and atrophic changes of supra-tentorial brain demonstrated by MRI. Methods Institutional review board approval was obtained for this retrospective study incorporating 65 consecutive patients presenting acutely who had both head CT and MRI. Arterial calcifications of the intracranial cavernous carotids (ICAC) were assigned a number (1 to 4) in the bone window images from CT scans. These 4 groups were then combined into high (grades 3 and 4) and low calcium (grades 1 and 2) subgroups. Brain MRI was independently evaluated to identify cortical and central atrophy. Demographics and cardiovascular risk factors were evaluated in subjects with high and low ICAC. Relationship between CT demonstrated ICAC and brain atrophy patterns were evaluated both without and with adjustment for cerebral ischemic scores and cardiovascular risk factors. Results Forty-six of the 65 (71%) patients had high ICAC on head CT. Subjects with high ICAC were older, and had higher prevalence of hypertension, diabetes, coronary artery disease (CAD), atrial fibrillation and history of previous stroke (CVA) compared to those with low ICAC. Age demonstrated strong correlation with both supratentorial atrophy patterns. There was no correlation between ICAC and cortical atrophy. There was correlation however between central atrophy and ICAC. This persisted even after adjustment for age. Conclusion Age is the most important determinant of atrophic cerebral changes. However, high ICAC demonstrated age independent association with central atrophy.

Purpose: Accurate detection of cerebral microbleeds (CMBs) is important for detection of multiple conditions. However, CMBs can be challenging to identify on MR images, especially for distinguishing CMBs from the mimic of calcification. We performed a comparative reader study to assess the diagnostic performance of two primary MR sequences for differentiating CMBs from calcification., Methods: Under IRB approved exempt retrospective protocol, 49 adult patients with identifiable intracranial hemorrhage who underwent multi-echo 3D Gradient Recall Echo (GRE) using 3T MRI were non-sequentially recruited under a retrospective IRB approved protocol. Multi-echo complex total field inversion quantitative susceptibility mapping (QSM) and susceptibility weighted imaging/phase (SWI/P) images were generated for all patients. 53 lesion ROIs were identified and classified on provided images by an expert panel of three neuroradiologists as either: CMB, Blood, Calcification, or Other. Three additional neuroradiologists subsequently reviewed the same SWI/P and QSM images in independent sessions and designated lesions as either blood and/or calcification using a 5-point Likert scale. Statistical analyses, on lesion classification and reader diagnostic accuracy, reader confidence-level, reader agreement-level, and the predictability of mean susceptibility values between SWI/P and QSM were conducted with logistic regression and calculation of Fleiss' κ, Kendall's w, Krippendorff's α., Results: Across all qualitative assessment and quantitative metrics measured (simple accuracy, confidence as degree of ground truth alignment, and inter-rater agreement) QSM outperformed SWI/P. Additionally, logistic regression of average QSM voxel susceptibility achieved near-perfect separation in differentiating between CMB and calcification in the limited number of CMB/Calcification ROIs, indicating a high predictability., Conclusion: Our study demonstrates that QSM offers improved detectability and classification of CMBs compared to the conventionally utilized SWI/P sequence. In addition, QSM simplifies the interpretation workflow by reducing the number of requisite images compared with the conventional counterpart, with improved diagnostic confidence., Competing Interests: Conflict of interest: P. Spincemaille is an inventor of QSM-related patents issued to Cornell University, holds equity in Medimagemetric LLC, and receives consulting fees from Medimagemetric LLC. Also, Y. Wang is an equity owner of the company Medimagemetric LLC, and M. Selim receives consulting fees from MedRhythma, Inc. and participates in the advisory board of MedRhythma, Inc. A.J. Thomas receives consulting fees from Stryker, Medtronic, and CereVas. C. Kang, P. Mehta, Y.S. Chang, R.A. Bhadelia, R. Rojas, M. Wintermark, J.B. Andre, E. Yang, A. Filippidis, Y. Wen, N.D. Forkert, and S. Soman declare that they have no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Background: Short-lasting cough-associated headache (CAH) in patients with Chiari I malformation (CMI) is believed to be due to transient worsening of cerebrospinal flow (CSF) obstruction at the foramen magnum. We assessed changes in CSF flow in response to coughing in CMI patients with CAH and compared with those without CAH and healthy participants (HPs) using real-time magnetic resonance imaging., Methods: Seventeen CMI patients (12 with CAH, 5 without CAH) and 6 HPs were prospectively assessed using real-time pencil-beam imaging magnetic resonance sequence. A 64-mm length pencil-beam imaging cylinder was placed at the craniocervical junction. CSF stroke volume (SV CSF ) was assessed during resting, postcoughing, and relaxation phases via a 90-second scan. SV CSF was measured at 6 levels at 5-mm intervals between 10 and 35 mm below the foramen magnum. During each phase, SV CSF was compared between CMI with and without CAH and HPs and corrected for multiple comparisons., Results: At multiple consecutive levels, postcoughing SV CSF was significantly lower in CMI with CAH compared with both CMI without CAH and HP (P < 0.05). No differences in postcoughing SV CSF were seen between CMI without CAH and HP. At rest or relaxation phase, no differences in SV CSF were seen between patients with and without CAH but minimal differences were seen between CMI with CAH and HP., Conclusions: A decrease in CSF flow after coughing in CMI patients with CAH supports the notion that CAH is caused by transient worsening of CSF flow obstruction at the foramen magnum., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: Posterior fossa decompression (PFD) surgery creates more space at the skull base, reduces the resistance to the cerebrospinal fluid motion, and alters craniocervical biomechanics. In this paper, we retrospectively examined the changes in neural tissue dimensions following PFD surgery on Chiari malformation type 1 adults., Methods: Measurements were performed on T2-weighted brain magnetic resonance images acquired before and 4 months after surgery. Measurements were conducted for neural tissue volume and spinal cord/brainstem width at 4 different locations; 2 width measurements were made on the brainstem and 2 on the spinal cord in the midsagittal plane. Cerebellar tonsillar position (CTP) was also measured before and after surgery., Results: Twenty-five adult patients, with a mean age of 38.9 ± 8.8 years, were included in the study. The cervical cord volume increased by an average of 2.3 ± 3.3% (P = 0.002). The width at the pontomedullary junction increased by 2.2 ± 3.5% (P < 0.01), while the width 10 mm caudal to this junction increased by 4.2 ± 3.9% (P < 0.0001). The spinal cord width at the base of second cervical vertebra and third cervical vertebra did not significantly change after surgery. The CTP decreased by 60 ± 37% (P < 0.0001) after surgery, but no correlation was found between CTP change and dimension change., Conclusions: The brainstem width and cervical cord volume showed a modest increase after PFD surgery, although standard deviations were large. A reduction in compression after PFD surgery may allow for an increase in neural tissue dimension. However, clinical relevance is unclear and should be assessed in future studies with high-resolution imaging., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Purpose: Chiari malformation type I (CMI) patients have been independently shown to have both increased resistance to cerebrospinal fluid (CSF) flow in the cervical spinal canal and greater cardiac-induced neural tissue motion compared to healthy controls. The goal of this paper is to determine if a relationship exists between CSF flow resistance and brain tissue motion in CMI subjects., Methods: Computational fluid dynamics (CFD) techniques were employed to compute integrated longitudinal impedance (ILI) as a measure of unsteady resistance to CSF flow in the cervical spinal canal in thirty-two CMI subjects and eighteen healthy controls. Neural tissue motion during the cardiac cycle was assessed using displacement encoding with stimulated echoes (DENSE) magnetic resonance imaging (MRI) technique., Results: The results demonstrate a positive correlation between resistance to CSF flow and the maximum displacement of the cerebellum for CMI subjects (r = 0.75, p = 6.77 × 10 -10 ) but not for healthy controls. No correlation was found between CSF flow resistance and maximum displacement in the brainstem for CMI or healthy subjects. The magnitude of resistance to CSF flow and maximum cardiac-induced brain tissue motion were not statistically different for CMI subjects with and without the presence of five CMI symptoms: imbalance, vertigo, swallowing difficulties, nausea or vomiting, and hoarseness., Conclusion: This study establishes a relationship between CSF flow resistance in the cervical spinal canal and cardiac-induced brain tissue motion in the cerebellum for CMI subjects. Further research is necessary to understand the importance of resistance and brain tissue motion in the symptomatology of CMI., (© 2023. The Author(s).)

Cranio-spinal volume and pressure changes associated with the cardiac-cycle and respiration are altered in Chiari I malformation (CMI) due to obstruction of cerebrospinal fluid (CSF) flow at the foramen magnum. With the introduction of motion-sensitive MRI sequences, it was envisioned that these could provide noninvasive information about volume-pressure dynamics at the cranio-cervical junction in CMI hitherto available only through invasive pressure measurements. Since the early 1990s, multiple studies have assessed CSF flow and brain motion in CMI. However, differences in design and varied approaches in the presentation of results and conclusions makes it difficult to fully comprehend the role of MR imaging of CSF flow and brain motion in CMI. In this review, a cohesive summary of the current status of MRI assessment of CSF flow and brain motion in CMI is presented. Simplified versions of the results and conclusions of previous studies are presented by dividing the studies in distinct topics: 1) comparing CSF flow and brain motion between healthy subjects (HS) and CMI patients (before and after surgery), 2) comparing CSF flow and brain motion to CMI severity and symptoms, and 3) comparing CSF flow and brain motion in CMI with and without syringomyelia. Finally, we will discuss our vision of the future directions of MR imaging in CMI patients. EVIDENCE LEVEL: 2. TECHNICAL EFFICACY: 5., (© 2023 International Society for Magnetic Resonance in Medicine.)

Chiari malformation Type I (CMI) is known to have an altered biomechanical environment for the brainstem and cerebellum; however, it is unclear whether these altered biomechanics play a role in the development of CMI symptoms. We hypothesized that CMI subjects have a higher cardiac-induced strain in specific neurological tracts pertaining to balance, and postural control. We measured displacement over the cardiac cycle using displacement encoding with stimulated echoes magnetic resonance imaging in the cerebellum, brainstem, and spinal cord in 37 CMI subjects and 25 controls. Based on these measurements, we computed strain, translation, and rotation in tracts related to balance. The global strain on all tracts was small (<1%) for CMI subject and controls. Strain was found to be nearly doubled in three tracts for CMI subjects compared to controls (p < 0.03). The maximum translation and rotation were ∼150 μm and ∼1 deg, respectively and 1.5-2 times greater in CMI compared to controls in four tracts (p < 0.005). There was no significant difference between strain, translation, and rotation on the analyzed tracts in CMI subjects with imbalance compared to those without imbalance. A moderate correlation was found between cerebellar tonsillar position and strain on three tracts. The lack of statistically significant difference between strain in CMI subjects with and without imbalance could imply that the magnitude of the observed cardiac-induced strain was too small to cause substantial damage to the tissue (<1%). Activities such as coughing, or Valsalva may produce a greater strain., (Copyright © 2023 by ASME.)

Purpose: Routine head and neck CTAs (CTA head+neck ) performed for dizziness in the Emergency Department (ED) has steadily increased, but its clinical utility is still poorly elucidated. Our purpose was to assess the radiologic outcomes of CTA head+neck in ED dizziness patients. Methods: ED dizziness patients with CTA head+neck from January 2010 through November 2019 were retrospectively identified and further stratified into central vertigo (CV), peripheral vertigo (PV), and non-specific dizziness (NSD) groups by final clinical diagnoses. Findings on CTA head+neck (vessel stenosis >50%, occlusion, dissection, and infarct), and infarct on subsequent MRI if performed, were assessed. Differences in imaging findings were analyzed using chi-square or Fisher's exact tests. Results: Of 867 dizziness patients, 88 were diagnosed with CV, 383 with PV, and 396 with NSD. On CTA head+neck , 11.4% of all patients had posterior CTA findings, including posterior occlusions (4.2%), dissections (1.2%), and infarcts (2.3%). CV patients had more posterior circulation findings (31.8%) versus PV (9.9%) and NSD (8.3%) patients (both p < 0.01). 21.6% of CV patients had acute infarcts on CT versus none for PV and 0.03% for NSD patients (both p < 0.01). On MRI, 46.6% of CV patients had acute posterior circulation infarcts versus none for PV and 0.3% for NSD patients ( p < 0.01). Conclusion: Diagnostic yield for CTA head+neck for dizziness patients is low except in central vertigo patients which constitute only 1/10th of CTAs performed. Our single institution results support that CTA head+neck is likely low-yield in patients with high clinical suspicion for PV or NSD and further studies are needed to test this hypothesis.

Introduction: In acute ischemic strokes (AIS), the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) and CT perfusion (CTP) are commonly used to determine mechanical thrombectomy eligibility. Prior work suggests that CTA source image (CTA-SI) ASPECTS (CTA asp ) and a newly described CTA maximum intensity projection (CTA-MIP) ASPECTS (MIP asp ) better predict the final infarct core. Our goal was to compare MIP asp to CTA asp and non-contrast CT ASPECTS (NCCT asp ) for predicting ischemic core and collaterals established by CTP., Methods and Materials: A single institution, retrospective database for AIS due to internal carotid artery (ICA) or proximal middle cerebral artery (MCA) occlusions between January 2016 and February 2021 was reviewed. We rated ASPECTS on NCCT, CTA-SI, and CTA-MIP at baseline, then used the automated RAPID software to measure CTP ischemic core volume. The accuracy of each ASPECTS in predicting ischemic core volume (ICV) >70 cc and Hypoperfusion intensity ratio (HIR) >0.4 was compared using the receiver operating characteristic (ROC) curve., Results: 122/319 patients fulfilled the inclusion criteria. Area under the curve (AUC) for MIP asp was significantly higher than NCCT asp and CTA asp for predicting ICV >70 cc (0.95 vs. 0.89 and 0.95 vs. 0.92, P =0.03 and P = 0.04). For predicting HIR >0.4, AUC for MIP asp was significantly higher than NCCT asp and CTA asp (0.85 vs. 0.72 and 0.85 vs. 0.81, P < 0.001 and P < 0.01)., Conclusion: The predictive accuracy of detecting ischemic stroke with ICV >70cc and HIR >0.4 can be significantly improved using the MIP asp instead of CTA asp or NCCT asp ., Competing Interests: Declaration of Competing Interest The authors have no relevant financial or non-financial interests to disclose., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Purpose: Some patients with idiopathic intracranial hypertension (IIH) have cerebellar tonsillar herniation ≥ 5 mm mimicking Chiari malformation I (CMI), which can result in misdiagnosis and unjustified treatment. Our purpose was to identify IIH patients with tonsillar herniation ≥ 5 mm (IIH TH ) and compare with CMI patients to assess imaging findings that could distinguish the two conditions., Methods: Ninety-eight patients with IIH, 81 patients with CMI, and 99 controls were retrospectively assessed. Two neuroradiologists blindly reviewed MR images. IIH TH patients were compared with CMI patients and controls regarding the extent of tonsillar herniation (ETH), bilateral transverse sinus stenosis (BTSS), hypophysis-sella ratio (HSR), and bilateral tortuosity of optic nerve (BTON)., Results: 13/98 (13.2%) IIH patients had tonsillar herniation ≥ 5 mm (IIH TH ) and were significantly younger and had higher BMI compared with CMI patients and controls. ETH was significantly less in the IIH TH than CMI (6.5 ± 2.4 mm vs. 10.9 ± 4.4 mm; p < 0.001). BTSS and HSR < 0.5 were more common in IIH TH than CMI (p < 0.001 and p = 0.003, respectively). No differences were seen between CMI and controls. BTON was significantly more common in IIH TH compared to control (p = 0.01) but not to the CMI (p = 0.36). Sensitivity and specificity to differentiate IIH TH from CMI were 69.2% and 96.1% for BTSS and 69.2% and 75.3% for HSR < 0.5., Conclusion: The presence of BTSS and/or HSR < 0.5 in patients with ETH ≥ 5 mm should suggest further evaluation to exclude IIH before considering CMI surgery., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background and Purpose: Computed tomography angiographies are frequently performed in the emergency department (ED) for the assessment of cervical artery dissection (CeAD) due to the high risk of associated morbidity, but their diagnostic utility is not fully evaluated. We assessed the radiological outcomes and clinical correlates of CTAs performed for suspected CeAD., Materials and Methods: CTAs for all indications (Indication ALL ) over a 10-year period were evaluated to identify those with CeAD. A subgroup of CTAs performed for suspected CeAD (Indication DISSECTION ) was identified and further assessed for clinical findings predictive of CeAD. Magnetic resonance angiography/fat-saturated images (MRA/FSI) performed after CTA were also assessed., Results: Nine-thousand-two-hundred-four CTAs were performed by our ED for Indication ALL of which 850 (9.2%) were for Indication DISSECTION . CeAD was noted in 1.5% (142/9204) among Indication ALL and in 6.1% (53/850) of Indication DISSECTION CTAs. The most common radiological findings were mural thrombus and eccentric lumen. In the Indication DISSECTION group, new headache (OR: 2.5, 95%CI: 1.2-5.7) and partial Horner syndrome (OR: 14.4, 95%CI: 4.2-49.9) predicted carotid dissection and cervical fracture (OR: 5.5, 95%CI: 2.1-14.6) predicted vertebral artery dissections. MRA/FSI confirmed CeAD in all positive cases, but in 2 CTAs read as negative, MRA/FSI was positive for vertebral artery dissection., Conclusion: Although the yield of CTAs for clinically suspected CeAD is low, the paucity of reliable clinical predictors, high risk of morbidity, availability in ED, and comparable performance to MRA/FSI justifies its widespread utilization for initial diagnosis of CeAD., (© 2022. The Author(s), under exclusive licence to American Society of Emergency Radiology (ASER).)

Introduction: Morphometric assessment of Chiari malformation type I (CMI) is typically performed on a midsagittal MRI. However, errors arising from an imprecise selection of the midsagittal plane are unknown. We define absolute parasagittal error as the absolute difference between morphometric measurements at the midsagittal and parasagittal planes. Our objective was to determine the absolute parasagittal error at various lateral distances for morphometric parameters commonly used in CMI research., Methods: Sagittal T1-weighted MRI scans of 30 CMI adult female subjects were included. Image sets were evaluated to assess 14 CMI morphometric parameters in the midsagittal plane and four parasagittal planes located 1 and 2 mm lateral (left and right). Comparisons between measurements at the midsagittal and parasagittal planes were conducted to determine the mean individual absolute and mean group parasagittal errors for all 14 parameters., Results: The mean individual absolute parasagittal error was > 1 unit (1 mm for lengths and 1 degree for angles) for 9/14 parameters within a lateral distance of 2 mm. No significant group parasagittal errors were seen in 14/14 parameters, including tonsillar position within a lateral distance of 2 mm., Conclusion: Our results show that the absolute errors for imprecise midsagittal plane selection may impact the clinical assessment of an individual patient. However, the impact on group measurements, such as in a research setting, will be minimal., Competing Interests: The authors have declared that no competing interests exist.

Background and Purpose: Spinal cord compression (SCC) requires rapid diagnosis in the emergent setting; however, current MRI protocols may be cumbersome for patients and clinicians. We sought to validate an abbreviated total spine MRI (TS-MRI) protocol using standard non-contrast sequences in the detection of SCC and other clinically significant findings (OCSF)., Methods: Two hundred six TS-MRI scans obtained over a 30-month period for SCC were included. Sagittal T2 (T2 sag ), sagittal T1 (T1 sag ), and sagittal STIR (IR sag ), as well as axial T2 (T2 ax ) images, were individually assessed independently by 2 reviewers for SCC, cauda equina compression (CEC), and OCSF. A protocol consisting of all the sequences was considered the gold standard. Sensitivity and specificity of single and combined MRI sequences for SCC/CEC and OCSF were determined and were tested for noninferiority relative to standard non-contrast sequences using a 5% noninferiority margin., Results: An abbreviated protocol of IR sag  + T2 ax provided the best performance with sensitivity and specificity of 100% (95%CI, 96.0-100.0) and 98.6% (95%CI, 95.6-99.7) for SCC/CEC and 100.0% (95%CI, 96.7-100.0), and 99.3% (95%CI, 96.6-99.9) for OCSF. The mean difference of sensitivity and specificity between IR sag  + T2 ax and standard protocol was 0.0% (95%CI, 0.0-4.0) and - 2.1% (95%CI, - 5.4 to - 0.6) for SCC/CEC and 0.0% (95%CI, 0.0-3.3) and - 1.5% (95%CI, - 4.8 to - 0.3) for OCSF, all within the noninferiority margin of 5%., Conclusions: An abbreviated TS-MRI protocol of IR sag  + T2 ax is noninferior to the standard non-contrast protocol, potentially allowing for faster emergent imaging diagnosis and triage., (© 2021. American Society of Emergency Radiology.)

Background and Purpose: Although the cerebellar tonsils are parasagittal structures, the extent of tonsillar herniation (ETH) in Chiari I malformation (CMI) is currently measured in the midsagittal plane. We measured the ETH of each cerebellar tonsil in the parasagittal plane and assessed their diagnostic utility by comparing them to the midsagittal ETH measurements in predicting cough-associated headache (CAH), an indicator of clinically significant disease in CMI., Methods: Eighty-five CMI patients with 3D-MPRAGE images were included. Neurosurgeons determined the presence of CAH. Sagittal images were used to measure ETH in the midsagittal (MS&#95;ETH) and parasagittal planes (by locating tonsillar tips on each side on reformatted coronal images). Given the parasagittal ETH (PS&#95;ETH) asymmetry in the majority of cases, they were considered Smaller&#95;PS&#95;ETH or Larger&#95;PS&#95;ETH. The accuracy of ETH measurements was assessed by the receiver operating characteristic (ROC) curve., Results: Of 85 patients, 46 reported CAH. ROC analysis showed an area under the curve (AUC) of 0.78 for Smaller&#95;PS&#95;ETH significantly better than 0.65 for MS-ETH in predicting CAH ( p  = 0.001). An AUC of 0.68 for Larger&#95;PS&#95;ETH was not significantly different from MS&#95;ETH. The sensitivity and specificity of predicting CAH were 87% and 28% for MS&#95;ETH >6 mm versus 90% and 46% for Smaller&#95;PS&#95;ETH >6 mm, and 52% and 67% for MS&#95;ETH >9 mm versus 48% and 87% for Smaller&#95;PS&#95;ETH >9 mm. At ETH >15 mm, no differences were seen between the measurements., Conclusions: Diagnostic utility of ETH measurements in detecting clinically significant CMI can be improved by parasagittal measurements of the cerebellar tonsillar herniation.

Purpose: Emergent spinal MRI is recommended for patients with back pain and red flags for infection. However, many of these studies are negative due to low prevalence of spinal infections. Our purpose was to assess if C-reactive protein (CRP) can be used to guide effective utilization of emergent MRI for spinal infections., Methods: 316/960 (33%) MRIs performed for infection by the emergency department over 75-month period had CRP levels obtained at presentation, after excluding patients receiving antibiotic or had spinal surgery in < 1 month. An MRI was considered positive when there was imaging evidence of spinal infection confirmed on follow-up by surgery/biopsy/drainage or definitive therapy. A CRP of ≤ 10 mg/L was considered normal and > 100 mg/L as highly elevated., Results: CRP was normal in 95/316 (30%) and abnormal in 221/316 (70%) patients. MRI was positive in 43/316 (13.6%) patients, all of whom had abnormal CRP. CRP (p < 0.001) and intravenous drug use (IVDU; p = 0.002) were independently associated with a positive MRI. Receiver operator characteristic (ROC) analysis showed AUC of 0.76 for CRP, slightly improving with IVDU. Sensitivity, specificity, and negative predictive values for CRP level cut-off: 10 mg/L, 100%, 35%, and 100%, and 100 mg/L, 58%, 70% and 91%, respectively., Conclusion: Abnormal CRP, although extremely sensitive, lacks specificity in predicting a positive MRI for spinal infection unless highly elevated. However, a normal CRP (absent recent antibiotic or surgery) makes spinal infection unlikely, and its routine use as a screening test can help reducing utilization of emergent MRI for this purpose.

Cough-associated headaches (CAHs) are thought to be distinctive for Chiari malformation type I (CMI) patients and have been shown to be related to the motion of cerebrospinal fluid (CSF) near the foramen magnum (FM). We used computational fluid dynamics (CFD) to compute patient-specific resistance to CSF motion in the spinal canal for CMI patients to determine its accuracy in predicting CAH. Fifty-one symptomatic CMI patients with cerebellar tonsillar position (CTP) ≥ 5 mm were included in this study. The patients were divided into two groups based on their symptoms (CAH and non-CAH) by review of the neurosurgical records. CFD was utilized to simulate CSF motion, and the integrated longitudinal impedance (ILI) was calculated for all patients. A receiver operating characteristic (ROC) curve was evaluated for its accuracy in predicting CAH. The ILI for CMI patients with CAH (776 dyn/cm5, 288-1444 dyn/cm5; median, interquartile range) was significantly larger compared to non-CAH (285 dyn/cm5, 187-450 dyn/cm5; p = 0.001). The ILI was more accurate in predicting CAH in CMI patients than the CTP when the comparison was made using the area under the ROC curve (AUC) (0.77 and 0.70, for ILI and CTP, respectively). ILI ≥ 750 dyn/cm5 had a sensitivity of 50% and a specificity of 95% in predicting CAH. ILI is a parameter that is used to assess CSF blockage in the spinal canal and can predict patients with and without CAH with greater accuracy than CTP., (Copyright © 2021 by ASME.)

Background: Most patients with pineal cysts referred for neurosurgical consultation have no specific symptoms or objective findings except for pineal cyst size to help in management decisions. Our purpose was to assess the relationship between pineal cyst size and aqueductal CSF flow using PC-MRI., Methods: Eleven adult patients with pineal cysts (>1 cm) referred for neurosurgical consultations were included. Cyst volume was calculated using 3D T1 images. Phase contrast magnetic resonance imaging (PC-MRI) in axial plane with velocity encoding of 5 cm/sec was used to quantitatively assess CSF flow through the cerebral aqueduct to determine the aqueductal stroke volume, which was then correlated to cyst size using Pearson's correlation. Pineal cysts were grouped by size into small (6/11) and large (5/11) using the median value to compare aqueductal stroke volume using Mann-Whitney test., Results: Patients were 39±13 years (mean±SD) of age, and 10/11 (91%) were female. There was significant negative correlation between cyst volume and aqueductal stroke volume (r=0.74; P=0.009). Volume of small cysts (4954±2157 mm 3 ) was significantly different compared to large cysts (13,752±3738 mm 3 ; P=0.008). The aqueductal stroke volume of patients harboring large cysts 33±8 μL/cardiac cycle was significantly lower than that of patients with small cysts 96±29 μL/cardiac cycle (P=0.008)., Conclusions: Aqueductal CSF flow appears to decrease with increasing pineal cyst size. Our preliminary results provide first evidence that even in the absence of objective neurological findings or hydrocephalus; larger pineal cysts already display decreased CSF flow through the cerebral aqueduct.

Background and Purpose: Total spine MRIs are requested by the emergency department when focused imaging can not be ordered on the basis of history or clinical findings. However, their efficacy is not known. We assessed the following: 1) major radiologic and clinical outcomes of total spine MR imaging performed by the emergency department, and 2) whether the presence of a high-risk clinical profile and/or neurologic findings impacts the clinical outcomes., Materials and Methods: Total spine MRIs requested by the emergency department during a 28-month period were evaluated for major radiologic (cord compression, cauda equina compression, and other significant findings) and major clinical outcomes (hospital admission during the visit followed by an operation, radiation therapy, or intravenous antibiotics or steroids). Associations between a high-risk clinical profile (cancer, infection, coagulopathy) and/or the presence of neurologic findings and outcomes were assessed., Results: After we excluded trauma or nondiagnostic studies, 321/2047 (15.7%) MRIs ordered during study period were total spine MR imaging; 117/321 (36.4%) had major radiologic and 60/321 (18.6%) had major clinical outcomes (34/60 in <24 hours); and 58/117(49.6%) with major radiologic outcome were treated compared with 2/205 (1.0%) without (OR = 99, P  < .001). The presence of both a high-risk clinical profile and neurologic findings concurrently in a patient (142/321) increased the likelihood of major clinical outcomes during the same visit (OR = 3.1, P  < .001) and in <24-hours (OR = 2.6, P  = .01) compared with those with either a high-risk clinical profile or neurologic findings alone (179/321)., Conclusions: Total spine MR imaging ordered by our emergency department has a high radiologic and significant clinical yield. When a high-risk clinical profile and neurologic findings are both present in a patient, they should be prioritized for emergent total spine MR imaging, given the increased likelihood of clinical impact., (© 2020 by American Journal of Neuroradiology.)

Objective: The anterior thalamic nucleus (ATN) is a common target for deep brain stimulation (DBS) for the treatment of drug-refractory epilepsy. However, no atlas-based optimal DBS (active contacts) target within the ATN has been definitively identified. The object of this retrospective study was to analyze the relationship between the active contact location and seizure reduction to establish an atlas-based optimal target for ATN DBS., Methods: From among 25 patients who had undergone ATN DBS surgery for drug-resistant epilepsy between 2016 and 2018, those who had follow-up evaluations for more than 1 year were eligible for study inclusion. After an initial stimulation period of 6 months, patients were classified as responsive (≥ 50% median decrease in seizure frequency) or nonresponsive (< 50% median decrease in seizure frequency) to treatment. Stimulation parameters and/or active contact positions were adjusted in nonresponsive patients, and their responsiveness was monitored for at least 1 year. Postoperative CT scans were coregistered nonlinearly with preoperative MR images to determine the center coordinate and atlas-based anatomical localizations of all active contacts in the Montreal Neurological Institute (MNI) 152 space., Results: Nineteen patients with drug-resistant epilepsy were followed up for at least a year following bilateral DBS electrode implantation targeting the ATN. Active contacts located more adjacent to the center of gravity of the anterior half of the ATN volume, defined as the anterior center (AC), were associated with greater seizure reduction than those not in this location. Intriguingly, the initially nonresponsive patients could end up with much improved seizure reduction by adjusting the active contacts closer to the AC at the final postoperative follow-up., Conclusions: Patients with stimulation targeting the AC may have a favorable seizure reduction. Moreover, the authors were able to obtain additional good outcomes after electrode repositioning in the initially nonresponsive patients. Purposeful and strategic trajectory planning to target this optimal region may predict favorable outcomes of ATN DBS.

Purpose: Cough-associated headache (CAH) is the most distinctive symptom of patients with Chiari I malformation (CMI) and indicates clinically significant disease. We determined the clinical utility of simple 2D anatomic measurements performed on a PACS workstation by assessing their diagnostic accuracy in predicting CAH in CMI patients., Methods: Seventy-two consecutive CMI patients (cerebellar tonsillar herniation > 5 mm) with headache seen by neurosurgeons over 6 years were included. Sagittal T1 images were used by two readers to measure: extent of tonsillar herniation, lengths of the clivus and supra-occiput, McRae and pB-C2 lines, as well as clivus-canal, odontoid retroversion, and skull base angles. Neurosurgery notes were reviewed to determine presence of CAH. Mann-Whitney test was used to compare measurements between patients with and without CAH. Predictive accuracy was assessed by receiver operating characteristic (ROC) curve., Results: 47/72 (65.3%) CMI patients reported CAH. Tonsillar herniation with CAH (10.2 mm, 7-14 mm; median, interquartile range) was significantly greater than those without CAH (7.9 mm, 6.3-10.9 mm; p = 0.02). Tonsillar herniation ≥ 10 mm showed sensitivity and specificity of 51% and 68%, and tonsillar herniation > 14 mm showed sensitivity and specificity of 30% and 100%, respectively, for predicting CAH. Other 2D measurements showed no statistically significant differences., Conclusions: Among the 2D measurements used, only the extent of tonsillar herniation is different between CMI patients with and without CAH. Although CMI is diagnosed with tonsillar herniation of only 5 mm, we found that a much higher extent of herniation is needed to be predictive of CAH.

Background and Purpose: Unilateral decreased/nonvisualization of a transverse dural sinus on MRV poses a diagnostic dilemma when gadolinium administration is contraindicated. We determined the frequency of unilateral decreased/nonvisualization of the transverse dural sinus and the performance of pregadolinium MR imaging sequences in diagnosing transverse sinus thrombosis in the presence of unilateral decreased/nonvisualization on phase-contrast MRV., Materials and Methods: We conducted a retrospective review of consecutive 3D phase-contrast MRV (VENC, 30 cm/s) and routine brain imaging (noncontrast sagittal T1, axial T2, FLAIR, DWI, GRE, and postgadolinium 3D-MPRAGE images) performed during a 3-year period for a total of 208 patients. Nonvisualization of a transverse dural sinus was defined as ≥50% nonvisualization of the transverse sinus caliber versus the contralateral side on MRV. Noncontrast imaging findings were considered abnormal when hyperintense signal was present on T2, FLAIR, T1, and DWI, and there were T2* blooming artifacts on GRE and DWI. Postgadolinium 3D-MPRAGE was used to confirm the diagnosis of transverse sinus thrombosis., Results: Nonvisualization of a transverse dural sinus was observed in 72/208 (34.6%) patients on MRV; 56/72 (77.8%) were without transverse sinus thrombosis, and 16/72 (22.2%) patients had transverse dural sinus thrombosis. Nonvisualization of a transverse dural sinus was seen in 56/192 (29.2%) patients without transverse sinus thrombosis and 16/16 (100%) with transverse sinus thrombosis. Abnormal findings on DWI (transverse sinus hyperintense signal or T2* blooming artifact) are 93.8% sensitive and 100.0% specific for transverse sinus thrombosis. Other noncontrast MR imaging sequences ranged from 56.3%-68.8% sensitive and 91.1%-100.0% specific., Conclusions: Nonvisualization of a transverse dural sinus is a frequent phenomenon on phase-contrast MRV. DWI can be effectively used to exclude sinus thrombosis when nonvisualization of a transverse dural sinus is a diagnostic conundrum on phase-contrast MRV and contrast-enhanced studies are contraindicated., (© 2020 by American Journal of Neuroradiology.)

OBJECTIVE. Accurate diagnosis of spinal cord compression (SCC) or cauda equina compression (CEC) is important in the emergency setting so management decisions may be made promptly. The purpose of this study is to evaluate the performance of on-call radiology residents in interpreting total spine MRI studies for the detection of SCC or CEC. MATERIALS AND METHODS. On-call radiology residents' preliminary interpretation of total spine MRI studies performed over a period of two and half years were evaluated. Agreements and disagreements were determined for SCC (defined as severe spinal stenosis with compression of the spinal cord and lack of surrounding CSF), CEC (defined as > 75% narrowing of the lumbar canal and lack of CSF in the thecal sac), and the presence of other significant findings that might impact clinical management. Studies with true-positive, true-negative, false-positive, and false-negative findings were identified. RESULTS. SCC or CEC was present in 72 of the 295 studies with preliminary interpretations done by on-call residents. The sensitivity and specificity for detecting SCC or CEC were 93.1% and 98.2%, respectively. Sensitivity was higher for 3rd- and 4th-year residents (97.7%) than for 2nd-year residents (86.2%). Other significant findings were present in 34 of the 295 studies. The overall sensitivity and specificity for the detection of other significant findings were 85.3% and 100.0%, respectively. The level of training did not affect the detection of other significant findings. CONCLUSION. The overall sensitivity of on-call radiology residents' interpretation of total spine MR images for the detection of SCC or CEC was high, improving with their level of training. However, residents' sensitivity was slightly less for the detection of other significant findings. Resident performance can be further improved with focused training and the use of a preliminary interpretation template.

Background and Purpose: Automated imaging software is integral to decision-making in acute ischemic stroke (AIS) during extended time windows. RAPID software is the most widely used and has been validated in landmark endovascular trials. Olea software is another commercially available and FDA-approved software, but has not been studied in AIS trials. We aimed to compare the diagnostic utility and accuracy of RAPID and Olea in everyday clinical practice outside of a clinical trial., Methods: We analyzed prospectively-collected data from a consecutive cohort of 141 patients with suspected AIS who underwent computed tomography perfusion upon presentation followed by diffusion-weighted magnetic resonance imaging (DWI-MRI) within 24-48 hours. Core infarct was defined as the region with a relative cerebral blood flow (rCBF) less than 30% on RAPID and rCBF less than 40% on Olea (default settings). We also evaluated rCBF less than 30% on Olea to match RAPID's default setting. Infarct volume on DWI-MRI was measured using a semiautomated segmentation method., Results: Twenty-one patients were excluded; 14 due to poor bolus tracking and/or motion artifact, and 7 due to software failure. The software failure rate was 4.7% [6/127] with RAPID versus .78% [1/127] with Olea (P = .12). For the remaining 120 patients, the sensitivity and specificity for detecting an acute infarct were 40.5% and 97.6% for RAPID; 50.6% and 85.4% for Olea; and for detecting large infarcts (≥70 mL on DWI-MRI) 73.7% and 81.2% for RAPID; 73.7% and 68.3% for Olea. Core infarct volume on RAPID was more closely correlated with DWI-MRI infarct volume (rho = .64) than Olea (rho = .42)., Conclusions: Our head-to-head comparison of these 2 commonly-used softwares in the clinical setting elucidates the pros and cons of their use to guide decision-making for AIS management in the acute setting., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Headache is a common symptom in patients with Chiari I malformation (CMI), characterized by 5 mm or greater cerebellar tonsillar herniation below foramen magnum. Radiologists should be aware of the different types of headaches reported by CMI patients and which headache patterns are distinctive features of the diagnosis. A methodical imaging strategy is required to fully assess a CMI patient to exclude secondary causes of tonsillar herniation such as intracranial hypotension or associated conditions such as syrinx. Both anatomic and physiologic imaging can help determine if headaches are CMI associated, and assist clinicians in therapeutic decision making., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background and Purpose: No MR imaging measurement criteria are available for the diagnosis of optic nerve atrophy. We determined a threshold optic nerve area on MR imaging that predicts a clinical diagnosis of optic nerve atrophy and assessed the relationship between optic nerve area and retinal nerve fiber layer thickness measured by optical coherence tomography, an ancillary test used to evaluate optic nerve disorders., Materials and Methods: We evaluated 26 patients with suspected optic nerve atrophy (8 with unilateral, 13 with bilateral and 5 with suspected but not demonstrable optic nerve atrophy) who had both orbital MR imaging and optical coherence tomography examinations. Forty-five patients without optic nerve atrophy served as controls. Coronal inversion recovery images were used to measure optic nerve area on MR imaging. Retinal nerve fiber layer thickness was determined by optical coherence tomography. Individual eyes were treated separately; however, bootstrapping was used to account for clustering when appropriate. Correlation coefficients were used to evaluate relationships; receiver operating characteristic curves, to investigate predictive accuracy., Results: There was a significant difference in optic nerve area between patients' affected eyes with optic nerve atrophy (mean, 3.09 ± 1.09 mm 2 ), patients' unaffected eyes (mean, 5.27 ± 1.39 mm 2 ; P = .008), and control eyes (mean, 6.27 ± 2.64 mm 2 ; P < .001). Optic nerve area ≤ 4.0 mm 2 had a sensitivity of 0.85 and a specificity of 0.83 in predicting the diagnosis of optic nerve atrophy. A significant relationship was found between optic nerve area and retinal nerve fiber layer thickness ( r = 0.68, P < .001)., Conclusions: MR imaging-measured optic nerve area ≤ 4.0 mm 2 has moderately high sensitivity and specificity for predicting optic nerve atrophy, making it a potential diagnostic tool for radiologists., (© 2019 by American Journal of Neuroradiology.)

The recently proposed diagnostic algorithm for progressive multifocal leukoencephalopathy underscores the importance of imaging and emphasizes the role of the radiologist in the diagnostic workup. We describe a case series of patients with visual symptoms and a typical pattern of brain involvement in definite progressive multifocal leukoencephalopathy, for which we have coined the term barbell sign.

Schwannomas of cranial nerves in the absence of systemic neurofibromatosis are relatively rare. Among these, schwannomas of the trochlear nerve are even less common. They can be found incidentally or when they cause diplopia or other significant neurological deficits. Treatment options include observation only, neuro-ophthalmological intervention, and/or neurosurgical management via resection or sterotactic radiosurgery (SRS). In recent years, the latter has become an attractive therapeutic tool for a number of benign skull base neoplasm including a small number of reports on its successful use for trochlear Schwannomas. However, no treatment algorithm for the management of these tumors has been proposed so far. The goal of this manuscript is to illustrate a case series of this rare entity and to suggest a rational treatment algorithm for trochlear schwannomas, based on our institutional experience of recent cases, and a pertinent review of the literature. Including our series of 5 cases, a total of 85 cases reporting on the management of trochlear schwannomas have been published. Of those reported, less than half (40 %) of patients underwent surgical resection, whereas the remainder were managed conservatively or with SRS. Seventy-six percent (65/85) of the entire cohort presented with diplopia, which was the solitary symptom in over half of the cases (n = 39). All patients who presented with symptoms other than diplopia or headaches as solitary symptoms underwent surgical resection. Patients in the non-surgical group were mostly male (M/F = 3.5:1), presented at an older age and had shorter mean diameter (4.6 vs. 30.4 mm, p < 0.0001) when compared to the surgical group. Twelve patients in the entire cohort were treated with SRS, none of whom had undergone surgical resection before or after radiation treatment. Trochlear schwannoma patients without systemic neurofibromatosis are rare and infrequently reported in the literature. Of those, patients harboring symptomatic trochlear Schwannomas do not form a single homogenous group, but fall into two rather distinct subgroups regarding demographics and clinical characteristics. Among those patients in need of intervention, open microsurgical resection as well as less invasive treatment options exist, which all aim at safe relief of symptoms and prevention of progression. Both open microsurgical removal as well as SRS can achieve good long-term local control. Consequently, a tailored multidisciplinary treatment algorithm, based on the individual presentation and tumor configuration, is proposed.

Background and Purpose: Currently no quantitative objective test exists to determine disease severity in a patient with Chiari I malformation. Our aim was to correlate disease severity in symptomatic patients with Chiari I malformation with cough-associated changes in CSF flow as measured with real-time MR imaging., Materials and Methods: Thirteen symptomatic patients with Chiari I malformation (tonsillar herniation of ≥5 mm) were prospectively studied. A real-time, flow-sensitized pencil-beam MR imaging scan was used to measure CSF stroke volume during rest and immediately following coughing and relaxation periods (total scan time, 90 seconds). Multiple posterior fossa and craniocervical anatomic measurements were also obtained. Patients were classified into 2 groups by neurosurgeons blinded to MR imaging measurements: 1) nonspecific Chiari I malformation (5/13)-Chiari I malformation with nonspecific symptoms like non-cough-related or mild occasional cough-related headache, neck pain, dizziness, paresthesias, and/or trouble swallowing; 2) specific Chiari I malformation (8/13)-patients with Chiari I malformation with specific symptoms and/or objective findings like severe cough-related headache, myelopathy, syringomyelia, and muscle atrophy. The Spearman correlation was used to determine correlations between MR imaging measurements and disease severity, and both groups were also compared using a Mann-Whitney U test., Results: There was a significant negative correlation between the percentage change in CSF stroke volume (resting to postcoughing) and Chiari I malformation disease severity ( R = 0.59; P = .03). Mann-Whitney comparisons showed the percentage change in CSF stroke volume (resting to postcoughing) to be significantly different between patient groups ( P = .04). No other CSF flow measurement or anatomic measure was significantly different between the groups., Conclusions: Our exploratory study suggests that assessment of CSF flow response to a coughing challenge has the potential to become a valuable objective noninvasive test for clinical assessment of disease severity in patients with Chiari I malformation., (© 2018 by American Journal of Neuroradiology.)

Background: There is evidence that Alzheimer's disease (AD) has significant cerebrovascular etiopathogenesis. Understanding potentially modifiable risk factors for vascular disease can help design long-term intervention strategies for controlling or preventing cognitive dysfunction attributable to cerebrovascular disease., Objective: To evaluate the presence and severity of markers of cerebrovascular pathology, its relationship to diagnostic categories of dementia, including AD, and association with the metabolic biomarker homocysteine., Methods: In a cross-sectional observational study, 340 community-dwelling elders received a clinical evaluation including brain MRI and neuropsychological tests. Dementia and mild cognitive impairment (MCI) were diagnosed by consensus committee. Fasting total plasma homocysteine was measured. Statistical analyses were adjusted for demographics and cerebrovascular risk factors., Results: Nearly 25% of those diagnosed with AD had small vessel infarcts (SVI). Periventricular white matter hyperintensity (pvWMHI) was prevalent in participants with AD (61%) or MCI (amnesic 61% and non-amnesic 54%, respectively). Participants with SVI and/or pvWMHI also had greater brain atrophy. Homocysteine concentrations were higher in individuals with cerebrovascular findings than in those without. In individuals with cerebrovascular disease, homocysteine was inversely related to executive function (p = 0.022) and directly related to degree of brain atrophy (p = 0.009)., Conclusions: We demonstrated a significant prevalence of small vessel markers of cerebrovascular pathology in individuals diagnosed with AD, with a significant concurrence between cerebrovascular disease and brain and ventricular atrophy. While current research on AD has focused on amyloid-βpeptide deposition, tau-pathology, and microglial activation and inflammation, greater attention to the cerebrovascular contribution to this neurodegenerative disease presents an additional target for therapeutic prevention and intervention.

Background and Purpose: Acute C1-C2 fractures are difficult to detect on MR imaging due to a paucity of associated bone marrow edema. The purpose of this study was to determine the diagnostic utility of increased STIR signal in the posterior atlanto-occipital and atlantoaxial membrane complex (PAOAAM) in the detection of acute C1-C2 fractures on MR imaging., Materials and Methods: Eighty-seven patients with C1-C2 fractures, 87 with no fractures, and 87 with other cervical fractures with acute injury who had both CT and MR imaging within 24 hours were included. All MR images were reviewed by 2 neuroradiologists for the presence of increased STIR signal in the PAOAAM and interspinous ligaments at other cervical levels. Sensitivity and specificity of increased signal within the PAOAAM for the presence of a C1-C2 fracture were assessed., Results: Increased PAOAAM STIR signal was seen in 81/87 patients with C1-C2 fractures, 6/87 patients with no fractures, and 51/87 patients with other cervical fractures with 93.1% sensitivity versus those with no fractures, other cervical fractures, and all controls. Specificity was 93.1% versus those with no fractures, 41.4% versus those with other cervical fractures, and 67.2% versus all controls for the detection of acute C1-C2 fractures. Isolated increased PAOAAM STIR signal without increased signal in other cervical interspinous ligaments showed 89.7% sensitivity versus all controls. Specificity was 95.3% versus those with no fractures, 83.7% versus those with other cervical fractures, and 91.4% versus all controls., Conclusions: Increased PAOAAM signal on STIR is a highly sensitive indicator of an acute C1-C2 fracture on MR imaging. Furthermore, increased PAOAAM STIR signal as an isolated finding is highly specific for the presence of a C1-C2 fracture, making it a useful sign on MR imaging when CT is either unavailable or the findings are equivocal., (© 2017 by American Journal of Neuroradiology.)

Background: There is a potential role of choline in cardiovascular and cerebrovascular disease through its involvement in lipid and one-carbon metabolism. Objective: We evaluated the associations of plasma choline and choline-related compounds with cardiometabolic risk factors, history of cardiovascular disease, and cerebrovascular pathology. Design: A cross-sectional subset of the Nutrition, Aging, and Memory in Elders cohort who had undergone MRI of the brain ( n = 296; mean ± SD age: 73 ± 8.1 y) was assessed. Plasma concentrations of free choline, betaine, and phosphatidylcholine were measured with the use of liquid-chromatography-stable-isotope dilution-multiple-reaction monitoring-mass spectrometry. A volumetric analysis of MRI was used to determine the cerebrovascular pathology (white-matter hyperintensities and small- and large-vessel infarcts). Multiple linear and logistic regression models were used to examine relations of plasma measures with cardiometabolic risk factors, history of cardiovascular disease, and radiologic evidence of cerebrovascular pathology. Results: Higher concentrations of plasma choline were associated with an unfavorable cardiometabolic risk-factor profile [lower high-density lipoprotein (HDL) cholesterol, higher total homocysteine, and higher body mass index (BMI)] and greater odds of large-vessel cerebral vascular disease or history of cardiovascular disease but lower odds of small-vessel cerebral vascular disease. Conversely, higher concentrations of plasma betaine were associated with a favorable cardiometabolic risk-factor profile [lower low-density lipoprotein (LDL) cholesterol and triglycerides] and lower odds of diabetes. Higher concentrations of plasma phosphatidylcholine were associated with characteristics of both a favorable cardiometabolic risk-factor profile (higher HDL cholesterol, lower BMI, lower C-reactive protein, lower waist circumference, and lower odds of hypertension and diabetes) and an unfavorable profile (higher LDL cholesterol and triglycerides). Conclusion: Choline and its metabolites have differential associations with cardiometabolic risk factors and subtypes of vascular disease, thereby suggesting differing roles in the pathogenesis of cardiovascular and cerebral large-vessel disease compared with that of small-vessel disease., (© 2017 American Society for Nutrition.)

Background and Purpose: Invasive pressure studies have suggested that CSF flow across the foramen magnum may transiently decrease after coughing in patients with symptomatic Chiari I malformation. The purpose of this exploratory study was to demonstrate this phenomenon noninvasively by assessing CSF flow response to coughing in symptomatic patients with Chiari I malformation by using MR pencil beam imaging and to compare the response with that in healthy participants., Materials and Methods: Eight symptomatic patients with Chiari I malformation and 6 healthy participants were studied by using MR pencil beam imaging with a temporal resolution of ∼50 ms. Patients and healthy participants were scanned for 90 seconds (without cardiac gating) to continuously record cardiac cycle-related CSF flow waveforms in real-time during resting, coughing, and postcoughing periods. CSF flow waveform amplitude, CSF stroke volume, and CSF flow rate (CSF Flow Rate = CSF Stroke Volume × Heart Rate) in the resting and immediate postcoughing periods were determined and compared between patients and healthy participants., Results: There was no significant difference in CSF flow waveform amplitude, CSF stroke volume, and the CSF flow rate between patients with Chiari I malformation and healthy participants during rest. However, immediately after coughing, a significant decrease in CSF flow waveform amplitude (P < .001), CSF stroke volume (P = .001), and CSF flow rate (P = .001) was observed in patients with Chiari I malformation but not in the healthy participants., Conclusions: Real-time MR imaging noninvasively showed a transient decrease in CSF flow across the foramen magnum after coughing in symptomatic patients with Chiari I malformation, a phenomenon not seen in healthy participants. Our results provide preliminary evidence that the physiology-based imaging method used here has the potential to be an objective clinical test to differentiate symptomatic from asymptomatic patients with Chiari I malformation., (© 2016 by American Journal of Neuroradiology.)

Background and Purpose: Fast spin-echo short τ inversion recovery sequences have been very useful for MR imaging-guided deep brain stimulation procedures in Parkinson disease. However, high-quality fast spin-echo imaging deposits significant heat, exceeding FDA-approved limits when patients already have undergone deep brain stimulation and need a second one or a routine brain MR imaging for neurologic indications. We have developed a STIR sequence with an ultra-low specific absorption rate that meets hardware limitations and produces adequate tissue contrast in cortical and subcortical brain tissues for deep brain stimulation recipients., Materials and Methods: Thirteen patients with medically refractory Parkinson disease who qualified for deep brain stimulation were imaged at 1.5T with a fast spin-echo short τ inversion recovery sequence modified to meet conditional MR imaging hardware and specific absorption rate restrictions. Tissue contrast-to-noise ratios and implant localization were objectively and subjectively compared by 2 neuroradiologists, and image quality for surgical planning was assessed by a neurosurgeon for high and low specific absorption rate images., Results: The mean contrast-to-noise ratio for cerebral tissues without including the contrast-to-noise ratio for ventricular fluid was 35 and 31 for high and low specific absorption rate images. Subjective ratings for low specific absorption rate tissue contrast in 77% of patients were identical to (and in a few cases higher than) those of high specific absorption rate contrast, while the neurosurgical coordinates for fusing the stereotactic atlas with low specific absorption rate MR imaging were equivalent to those of the high specific absorption rate for 69% of patients., Conclusions: Patients with Parkinson disease who have already had a deep brain stimulation face a risk of neural injury if routine, high specific absorption rate MR imaging is performed. Our modified fast spin-echo short τ inversion recovery sequence conforms to very conservative radiofrequency safety limits, while it maintains high tissue contrast for presurgical planning, postsurgical assessment, and radiologic evaluations with greater confidence for radiofrequency safety., (© 2014 by American Journal of Neuroradiology.)

Background: For patients with deep brain stimulators (DBS), local absorbed radiofrequency (RF) power is unknown and is much higher than what the system estimates. We developed a comprehensive, high-quality brain magnetic resonance imaging (MRI) protocol for DBS patients utilizing three-dimensional (3D) magnetic resonance sequences at very low RF power., Methods: Six patients with DBS were imaged (10 sessions) using a transmit/receive head coil at 1.5 Tesla with modified 3D sequences within ultra-low specific absorption rate (SAR) limits (0.1 W/kg) using T2 , fast fluid-attenuated inversion recovery (FLAIR) and T1 -weighted image contrast. Tissue signal and tissue contrast from the low-SAR images were subjectively and objectively compared with routine clinical images of six age-matched controls., Results: Low-SAR images of DBS patients demonstrated tissue contrast comparable to high-SAR images and were of diagnostic quality except for slightly reduced signal., Conclusions: Although preliminary, we demonstrated diagnostic quality brain MRI with optimized, volumetric sequences in DBS patients within very conservative RF safety guidelines offering a greater safety margin., (© 2014 International Parkinson and Movement Disorder Society.)

Small vessel (SV) and large vessel (LV) brain infarcts are distinct pathologies. Using a homebound elderly sample, the numbers of either infarct subtypes were similar between those apolipoprotein E4 allele (ApoE4) carriers (n = 80) and noncarriers (n = 243). We found that the higher the number of SV infarcts, but not LV infarcts, a participant had, the higher the activity of substrate V degradation in serum especially among ApoE4 carriers (β = +0.154, SE = 0.031, P < .0001) after adjusting for the confounders. Since substrate V degradation could be mediated by insulin-degrading enzyme (IDE) or/and angiotensin-converting enzyme (ACE), but no relationship was found between SV infarcts and specific ACE activities, blood IDE may be a useful biomarker to distinguish the brain infarct subtypes. Insulin-degrading enzyme in blood may also imply an important biomarker and a pathological event in Alzheimer disease through SV infarcts in the presence of ApoE4.

Background and Purpose: MR imaging is currently not used to evaluate CSF flow changes due to short-lasting physiological maneuvers. The purpose of this study was to evaluate the ability of MR imaging to assess the CSF flow response to a Valsalva maneuver in healthy participants., Materials and Methods: A cardiac-gated fast cine-PC sequence with ≤15-second acquisition time was used to assess CSF flow in 8 healthy participants at the foramen magnum at rest, during, and immediately after a controlled Valsalva maneuver. CSF mean displacement volume VCSF during the cardiac cycle and CSF flow waveform App were determined. A work-in-progress real-time pencil-beam imaging method with temporal resolution ≤56 ms was used to scan 2 participants for 90 seconds during which resting, Valsalva, and post-Valsalva CSF flow, respiration, and HR were continuously recorded. Results were qualitatively compared with invasive craniospinal differential pressure measurements from the literature., Results: Both methods showed 1) a decrease from baseline in VCSF and App during Valsalva and 2) an increase in VCSF and App immediately after Valsalva compared with values measured both at rest and during Valsalva. Whereas fast cine-PC produced a single CSF flow waveform that is an average over many cardiac cycles, pencil-beam imaging depicted waveforms for each heartbeat and was able to capture many dynamic features of CSF flow, including transients synchronized with the Valsalva maneuver., Conclusions: Both fast cine-PC and pencil-beam imaging demonstrated expected changes in CSF flow with Valsalva maneuver in healthy participants. The real-time capability of pencil-beam imaging may be necessary to detect Valsalva-related transient CSF flow obstruction in patients with pathologic conditions such as Chiari I malformation.

Purpose: Segmentation and diffusion-tensor-imaging of the corpus callosum (CC) have been linked to gait impairment. However, such measurements are impracticable in clinical routine. The purpose of this study was to evaluate the association between simple linear measurements of CC thickness with gait., Methods: Two hundred and seventy-two community-dwelling subjects underwent neurological assessment and brain MRI. Mid-sagittal reformats of T1-weighted images were used to determine CC thickness. The association of measurements with clinical evaluation of gait was assessed by multivariate regression, controlling for numerous clinical and imaging confounders. Differences in CC thickness were, moreover, compared between subgroups with no, moderate or severe impairment of gait., Results: In univariate analyses, thickness of the genu and body of CC but not the splenium were associated with postural stability (P < 0.01). Multivariate regression revealed thickness of CC genu as the only imaging variable independently associated with gait (P = 0.01). Genu thickness was significantly different between subjects with high and low (P = 0.0003) or high and moderate (P = 0.001) risk of fall., Conclusion: Atrophy of the CC genu is an imaging marker of gait impairment in the elderly suggesting higher risk of fall. Simple linear measurements of CC can help in MRI evaluation of patients with gait impairment., Key Points: • Regional atrophy of the corpus callosum reflects disruption of gait regulation • Genu thickness on cranial MRI is an independent marker of gait impairment • Findings help in the MRI evaluation of patients with gait impairment.

Objective: Small-vessel disease is a common MRI finding that can be difficult to differentiate from other white matter (WM) diseases because of the lack of a specific pattern of brain involvement. The purpose of our study was to evaluate medial lemniscus hyperintensity seen on FLAIR images as an imaging marker for small-vessel disease., Materials and Methods: Two blinded neuroradiologists retrospectively reviewed 103 consecutive outpatient brain MRI studies. Medial lemniscus signal in the dorsal pons was evaluated visually on FLAIR images and after placing regions of interest (ROIs) on T2-weighted images. On the basis of the original interpretations, scans were divided into three categories: small-vessel disease, multiple sclerosis (MS), and normal or nonspecific WM changes. Cardiovascular risk factors were recorded. Analysis of variance and Fisher exact tests were used to determine group differences, and kappa statistics was used to determine interrater agreement., Results: Thirty-seven patients had small-vessel disease, 14 patients had MS, and 52 had nonspecific WM changes. Medial lemniscus hyperintensity was seen in about 20% of patients with small-vessel disease and was generally bilateral. Although ROI analyses identified a slightly higher number of patients with medial lemniscus signal > 20% of adjacent to normal-appearing brainstem, interrater reliability was moderate, and there were false-positive and false-negative cases in comparison with visual data. When small-vessel disease patients were further subdivided into mild or advanced subgroups, medial lemniscus hyperintensity was selectively seen in advanced small-vessel disease. Patients with medial lemniscus hyperintensity were older (p < 0.001) and had higher prevalence of diabetes (p = 0.03), hypertension (p = 0.009), and hypercholesterolemia (p = 0.03)., Conclusion: Medial lemniscus hyperintensity seen on FLAIR images is a reliable radiologic marker of advanced small-vessel disease.

Background: The Tinetti scale is a simple clinical tool designed to predict risk of falling by focusing on gait and stance impairment in elderly persons. Gait impairment is also associated with white matter (WM) abnormalities., Objective: To test the hypothesis that elderly subjects at risk for falling, as determined by the Tinetti scale, have specific patterns of WM abnormalities on diffusion tensor imaging., Design, Setting, and Patients: Community-based cohort of 125 homebound elderly individuals., Main Outcome Measures: Diffusion tensor imaging scans were analyzed using tract-based spatial statistics analysis to determine the location of WM abnormalities in subjects with Tinetti scale scores of 25 or higher (without risk of falls) and lower than 25 (with risk of falls).Multivariate linear least squares correlation analysis was performed to determine the association between Tinetti scale scores and local fractional anisotropy values on each skeletal voxel controlling for possible confounders., Results: In subjects with risk of falls (Tinetti scale score <25), clusters of abnormal WM were seen in the medial frontal and parietal subcortical pathways, genu and splenium of corpus callosum, posterior cingulum, prefrontal and orbitofrontal pathways, and longitudinal pathways that connect frontal-parietal-temporal lobes. Among these abnormalities, those in medial frontal and parietal subcortical pathways correlated with Mini-Mental State Examination scores, while the other locations were unrelated to these scores., Conclusions: Elderly individuals at risk for falls as determined by the Tinetti scale have WM abnormalities in specific locations on diffusion tensor imaging, some of which correlate with cognitive function scores.

Objective: The purpose of this article is to evaluate the accuracy of preliminary on-call radiology resident interpretation of CT angiography (CTA) compared with digital subtraction angiography (DSA) in detecting cerebral aneurysms in subarachnoid hemorrhage (SAH)., Materials and Methods: A retrospective review compared resident interpretations of head CTA performed after hours for SAH to the results of DSA. The sensitivity and specificity of resident interpretations were classified on a per-patient and per-aneurysm basis. The accuracy of resident interpretations was also determined according to aneurysm location and number., Results: Between January 2007 and December 2009, 83 patients with SAH underwent both CTA and DSA. DSA documented an aneurysm in 53 of 83 patients. Per patient, residents identified at least one aneurysm in 46 of 53 patients (87%). Per aneurysm, resident sensitivity and specificity for detecting aneurysms of any size were 62% and 91%, respectively, which improved for aneurysms 3 mm or larger to 73% and 97%, respectively. The posterior communicating and intracranial internal carotid arteries were resident "blind spots," with aneurysms 3 mm or larger detected with sensitivities of 33% and 50%, respectively. In contrast, anterior communicating artery aneurysms were correctly identified 95% of the time. In only 35% of cases with multiple aneurysms did residents correctly identify more than one aneurysm., Conclusion: The sensitivity of on-call resident interpretation of CTA for aneurysms in SAH is lower than expected, with a potential for delay in diagnosis and management in a small number of patients. Focused training to carefully review apparent blind spots and the frequency of multiple aneurysms may reduce inaccuracies.

The purpose of this study was to analyze the CSF flow in patients with Chiari I to determine differences between patients with and without CAH. Thirty patients with Chiari I malformation underwent cine-PC CSF flow imaging in the sagittal plane. CSF flow pulsations were analyzed by placing regions of interest in the anterior cervical subarachnoid space. Maximum CSF systolic (craniocaudal) and diastolic (caudocranial) velocities as well as the durations of CSF systole and diastole (measured in fractions of the cardiac cycle) were determined. In the region of interest just below the foramen magnum, patients with CAH had a significantly shorter CSF systole and longer diastole (P=.02). A CSF diastolic length of ≥0.75 of the cardiac cycle was 67% sensitive and 86% specific for CAH. Our results indicate that Cine-PC imaging can show differences in CSF flow patterns in patients with Chiari I with and without CAH.

Magnetic resonance imaging is the current imaging modality of choice in the evaluation of patients presenting with myelopathic symptoms in the search for spinal cord lesions. It is important for the radiologist to recognize and differentiate nonneoplastic from the neoplastic process of the spinal cord as the differentiation of the 2 entities is extremely crucial to the neurosurgeon. This article presents a broad spectrum of benign intramedullary spinal abnormalities including syrinx, contusion, abscess, infarction, myelitis, multiple sclerosis, sarcoid, cavernoma, and arteriovenous malformation. Rare intramedullary neoplasms including dermoid tumor, astrocytoma, ependymoma, hemangioblastoma, lymphoma, ganglioneuroblastoma, and metastases are also illustrated. The clinical presentation and magnetic resonance signal characteristics as well as the differential diagnosis of the intramedullary lesions are discussed. The potential pitfalls in the differentiation of tumors from nonneoplastic disease of the spinal cord are also elucidated.

Study Design: Retrospective study of surgical technique and outcome., Objective: The authors conducted a study to evaluate the ability of the TPS-TL (telescopic plate spacer-thoracolumbar) implant to correct kyphotic deformity and restore vertebral body height after vertebrectomy in the thoracolumbar spine., Summary of Background Data: TPS-TL is a novel vertebral body replacement device that consists of an expandable cage with an integrated plate component for transvertebral screw fixation., Methods: This is a retrospective study of 20 patients who underwent anterior column reconstruction with TPS-TL after a 1 or 2 level thoracolumbar vertebrectomy. Preoperative and postoperative sagittal alignment and vertebral body heights were radiologically analyzed in all patients. The mean follow-up was 14 months., Results: Preoperative and postoperative Cobb angles were measured to assess sagittal alignment. The average preoperative Cobb angle was 16.0 + or - 7 degrees. This was reduced to 9.8 + or - 10 degrees at the final follow-up (P<0.001). Percent of ideal vertebral body height was used to assess postoperative restoration of vertebral body height. This value was obtained by creating a ratio of the height of the effected vertebral levels to the height of the adjacent normal vertebral bodies. The mean percent of ideal vertebral body height improved from a preoperative value from 86.2 + or - 2% to 93.1 + or - 6% at the final follow-up (P<0.001)., Conclusions: The TPS-TL implant is effective in restoring vertebral body height and correcting kyphotic deformity after thoracolumbar vertebrectomy.

Objective: Although a short cervix is known to be associated with preterm birth, the patterns of three-dimensional, anatomic changes leading to a short cervix are unknown. Our objective was to (1) construct three-dimensional anatomic models during normal pregnancy and (2) use the models to compare cervical anatomy in the second and third trimester., Study Design: A cross-sectional study was performed in a population of patients referred to magnetic resonance imaging (MRI) for a fetal indication. Using magnetic resonance images for guidance, three-dimensional solid models of the following anatomic structures were constructed: amniotic cavity, uterine wall, cervical stroma, cervical mucosa and anterior vaginal wall. To compare cervical anatomy in the second and third trimester, models were matched according the size of the bony pelvis., Results: Fourteen patients were imaged and divided into two groups according to gestational age: 20-24 weeks (n=7)) and 31-36 weeks (n=7). Compared to the second trimester, the third trimester was associated with significant descent of the amniotic sac (p=.02). Descent of the amniotic sac was associated with modified anatomy of the uterocervical junction. These three-dimensional changes were associated with a cervix that appeared shorter in the third trimester., Conclusion: We report a technique for constructing MRI-based, three-dimensional anatomic models during pregnancy. Compared to the second trimester, the third trimester is associated with three-dimensional changes in the cervix and lower uterine segment.