Procedural learning and retention relative to explicit learning and retention in mild cognitive impairment and Alzheimer's disease using a modification of the trail making test

Amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD) dementia are characterized by pathological changes to the medial temporal lobes, resulting in explicit learning and retention reductions. Studies demonstrate that implicit/procedural memory processes are relatively intact in these populations, supporting different anatomical substrates for differing memory systems. This study examined differences between explicit and procedural learning and retention in individuals with aMCI and AD dementia relative to matched healthy controls. We also examined anatomical substrates using volumetric MRI. Results revealed expected difficulties with explicit learning and retention in individuals with aMCI and AD with relatively preserved procedural memory. Explicit verbal retention was associated with medial temporal cortex volumes. However, procedural retention was not related to medial temporal or basal ganglia volumes. Overall, this study confirms the dissociation between explicit relative to procedural learning and retention in aMCI and AD dementia and supports differing anatomical substrates.

Frontal and temporal lobe correlates of verbal learning and memory in aMCI and suspected Alzheimer's disease dementia

Alzheimer's disease is primarily known for deficits in learning and retaining new information. This has long been associated with pathological changes in the mesial temporal lobes. The role of the frontal lobes in memory in Alzheimer's disease is less well understood. In this study, we examined the role of the frontal lobes in learning, recognition, and retention of new verbal information, as well as the presence of specific errors (i.e., intrusions and false-positive errors). Participants included one hundred sixty-seven patients clinically diagnosed with amnestic mild cognitive impairment or suspected Alzheimer's disease dementia who were administered the California Verbal Learning Test and completed high-resolution MRI. We confirmed the role of the mesial temporal lobes in learning and retention, including the volumes of the hippocampus, entorhinal cortex, and parahippocampal gyrus. In addition, false-positive errors were associated with all volumes of the mesial temporal lobes and widespread areas within the frontal lobes. Errors of intrusion were related to the supplementary motor cortex and hippocampus. Most importantly, the mesial temporal lobes interacted with the frontal lobes for learning, recognition, and memory errors. Lower volumes in both regions explained more performance variance than any single structure. This study supports the interaction of the frontal lobes with the temporal lobes in many aspects of memory in Alzheimer's disease.

Focused ultrasound–mediated blood-brain barrier opening in Alzheimer’s disease: long-term safety, imaging, and cognitive outcomes

OBJECTIVE

MRI-guided low-intensity focused ultrasound (FUS) has been shown to reversibly open the blood-brain barrier (BBB), with the potential to deliver therapeutic agents noninvasively to target brain regions in patients with Alzheimer’s disease (AD) and other neurodegenerative conditions. Previously, the authors reported the short-term safety and feasibility of FUS BBB opening of the hippocampus and entorhinal cortex (EC) in patients with AD. Given the need to treat larger brain regions beyond the hippocampus and EC, brain volumes and locations treated with FUS have now expanded. To evaluate any potential adverse consequences of BBB opening on disease progression, the authors report safety, imaging, and clinical outcomes among participants with mild AD at 6–12 months after FUS treatment targeted to the hippocampus, frontal lobe, and parietal lobe.

METHODS

In this open-label trial, participants with mild AD underwent MRI-guided FUS sonication to open the BBB in β-amyloid positive regions of the hippocampus, EC, frontal lobe, and parietal lobe. Participants underwent 3 separate FUS treatment sessions performed 2 weeks apart. Outcome assessments included safety, imaging, neurological, cognitive, and florbetaben β-amyloid PET.

RESULTS

Ten participants (range 55–76 years old) completed 30 separate FUS treatments at 2 participating institutions, with 6–12 months of follow-up. All participants had immediate BBB opening after FUS and BBB closure within 24–48 hours. All FUS treatments were well tolerated, with no serious adverse events related to the procedure. All 10 participants had a minimum of 6 months of follow-up, and 7 participants had a follow-up out to 1 year. Changes in the Alzheimer’s Disease Assessment Scale–cognitive and Mini-Mental State Examination scores were comparable to those in controls from the Alzheimer’s Disease Neuroimaging Initiative. PET scans demonstrated an average β-amyloid plaque of 14% in the Centiloid scale in the FUS-treated regions.

CONCLUSIONS

This study is the largest cohort of participants with mild AD who received FUS treatment, and has the longest follow-up to date. Safety was demonstrated in conjunction with reversible and repeated BBB opening in multiple cortical and deep brain locations, with a concomitant reduction of β-amyloid. There was no apparent cognitive worsening beyond expectations up to 1 year after FUS treatment, suggesting that the BBB opening treatment in multiple brain regions did not adversely influence AD progression. Further studies are needed to determine the clinical significance of these findings. FUS offers a unique opportunity to decrease amyloid plaque burden as well as the potential to deliver targeted therapeutics to multiple brain regions in patients with neurodegenerative disorders.

Photorealistic Depiction of Intracranial Tumors Using Cinematic Rendering of Volumetric 3T MRI Data

RATIONALE AND OBJECTIVES

Cinematic Rendering (CR) incorporates a complex lightning model that creates photorealistic models from isotropic 3D imaging data. The utility of CR in depicting volumetric MRI data for pre-therapeutic planning is discussed, with intracranial tumors as a demonstrative example.

MATERIALS AND METHODS

We present a series of Cinematically Rendered intracranial tumors and discuss their utility in multidisciplinary pre-therapeutic evaluation. Isotropic, high-resolution, volumetric MRI data was collected, and CR was performed utilizing a proprietary application, "Anatomy Education" Siemens, Munich, Germany.

RESULTS

Discrimination of cortex to white matter, brain surface to vessels, subarachnoid space to cortex and skull to intracranial structures was achieved and optimized by using various display settings on the Anatomy education application. Progressive removal of tissue layers allowed for a comprehensive assessment of the entire region of interest. Complex, small structures were demonstrated in very high detail. The depth and architecture of the sulci was appreciated in a format that more closely mimicked gross pathology than traditional imaging modalities. With appropriate display settings, the relationship of the cortical surface to the adjacent vasculature was also delineated.

CONCLUSION

CR depicts the anatomic location of brain tumors in a format that depicts the relative proximity of adjacent structures in all dimensions and degrees of freedom. This allows for better conceptualization of the pathology and greater ease of communication between radiologists and other clinical teams, especially in the context of pretherapeutic planning.

Teleproctoring for Neurovascular Procedures: Demonstration of Concept Using Optical See-Through Head-Mounted Display, Interactive Mixed Reality, and Virtual Space Sharing-A Critical Need Highlighted by the COVID-19 Pandemic

BACKGROUND AND PURPOSE

Physician training and onsite proctoring are critical for safely introducing new biomedical devices, a process that has been disrupted by the pandemic. A teleproctoring concept using optical see-through head-mounted displays with a proctor's ability to see and, more important, virtually interact in the operator's visual field is presented.

MATERIALS AND METHODS

Test conditions were created for simulated proctoring using a bifurcation aneurysm flow model for WEB device deployment. The operator in the angiography suite wore a Magic Leap-1 optical see-through head-mounted display to livestream his or her FOV to a proctor's computer in an adjacent building. A Web-based application (Spatial) was used for the proctor to virtually interact in the operator's visual space. Tested elements included the quality of the livestream, communication, and the proctor's ability to interact in the operator's environment using mixed reality. A hotspot and a Wi-Fi-based network were tested.

RESULTS

The operator successfully livestreamed the angiography room environment and his FOV of the monitor to the remotely located proctor. The proctor communicated and guided the operator through the procedure over the optical see-through head-mounted displays, a process that was repeated several times. The proctor used mixed reality and virtual space sharing to successfully project images, annotations, and data in the operator's FOV for highlighting any device or procedural aspects. The livestream latency was 0.71 (SD, 0.03) seconds for Wi-Fi and 0.86 (SD, 0.3) seconds for the hotspot (P = .02). The livestream quality was subjectively better over the Wi-Fi.

CONCLUSIONS

New technologies using head-mounted displays and virtual space sharing could offer solutions applicable to remote proctoring in the neurointerventional space.

Multiple cerebral cavernous hemangiomas masquerading as hemorrhagic brain metastases

Intracranial hemorrhagic metastases are a relatively common finding in patients with thyroid carcinoma. Consequently, more unusual vascular lesions may be overlooked in contemplating a differential diagnosis in this patient group. A 50-year-old female with previously treated papillary thyroid carcinoma presented to the emergency department following new onset seizures. Her work up revealed multiple intraparenchymal brain lesions, hyperdense on computed tomography and demonstrating susceptibility effect, T1 shortening and contrast enhancement on magnetic resonance imaging, suggestive of metastases. Subsequent studies revealed lesional architecture consistent with multiple cavernous malformations, made evident by resolution of edema and evolution of blood products. Clinicians should be aware of the possibility of unusual intracranial hemorrhagic lesions in oncology patients which may only become evident on serial imaging evaluation. Cavernous hemangioma has typical MRI characteristic features which includes “mulberry” appearance on T2-weighted and fluid attenuation inversion recovery images with varying internal signal intensity which indicates multiple stages of blood products within the cavernous hemangioma. The lesions commonly have a typical T2-weighted dark hemosiderin rim. Blood sensitive demonstrates prominent surrounding hypointensity representing blooming secondary to internal blood products and/or calcification, if present. Cavernous hemangioma may rarely demonstrate some degree of contrast enhancement. Perfusion imaging may show alteration in capillary permeability involving cavernous malformations which has been previously described in the literature.

Effect of antenatal magnesium sulphate on MRI biomarkers of white matter development at term equivalent age: The magnum study

Background

Magnesium sulphate given to women immediately prior to very preterm birth protects the perinatal brain, so fewer babies die or develop cerebral palsy. How magnesium sulphate exerts these beneficial effects remains uncertain. The aim of the MagNUM Study was to assess the effect of exposure to antenatal magnesium sulphate on MRI measures of brain white matter microstructure at term equivalent age.

Methods

Nested cohort study within the randomised Magnesium sulphate at 30 to <34 weeks’ Gestational age Neuroprotection Trial (MAGENTA). Mothers at risk of preterm birth at 30 to <34 weeks’ gestation were randomised to receive either 4 g of magnesium sulphate heptahydrate [8 mmol magnesium ions], or saline placebo, infused over 30 min when preterm birth was planned or expected within 24 h. Participating babies underwent diffusion tensor MRI at term equivalent age. The main outcomes were fractional anisotropy across the white matter tract skeleton compared using Tract-based Spatial Statistics (TBSS), with adjustment for postmenstrual age at birth and at MRI, and MRI site. Researchers and families were blind to treatment group allocation during data collection and analyses.

Findings

Of the 109 participating babies the demographics of the 60 babies exposed to magnesium sulphate were similar to the 49 babies exposed to placebo. In babies whose mothers were allocated to magnesium sulphate, fractional anisotropy was higher within the corticospinal tracts and corona radiata, the superior and inferior longitudinal fasciculi, and the inferior fronto-occipital fasciculi compared to babies whose mothers were allocated placebo (P < 0.05).

Interpretation

In babies born preterm, antenatal magnesium sulphate exposure promotes development of white matter microstructure in pathways affecting both motor and cognitive function. This may be one mechanism for the neuroprotective effect of magnesium sulphate treatment prior to preterm birth.

Funding

Health Research Council of New Zealand.

An Elusive Case of Mycosis Fungoides: Case Report and Review of the Literature

Erythroderma refers to a spectrum of skin diseases resulting in diffuse erythema and scaling encompassing ≥ 90% of the body surface area. The differential diagnosis ranges from primary dermatologic diseases such as atopic dermatitis and psoriasis to potentially deadly causes such as staphylococcal toxic shock syndrome, toxic epidermal necrolysis, and malignancy. Cutaneous T cell lymphoma (CTCL) is an uncommon but highly morbid cause of erythroderma. This non-Hodgkin lymphoma remains a diagnostic challenge due to its variable clinical presentation and varied histologic features. Mycosis fungoides (MF) is the most common form of CTCL. Making a timely diagnosis is challenging as it may mimic inflammatory diseases of the skin including eczema, psoriasis, lichen planus, and cutaneous lupus. We present a case of a 58-year-old man who presented with 5 years of cutaneous symptoms and several months of fevers and night sweats, ultimately diagnosed as MF. Owing to diffuse CD30 positivity, he was a candidate for brentuximab vedotin, an antibody-drug conjugate medication that selectively targets the CD30 antigen. This resulted in an excellent therapeutic response.

Efficacy and Safety of Percutaneous Microwave Ablation and Cementoplasty in the Treatment of Painful Spinal Metastases and Myeloma

BACKGROUND AND PURPOSE

Painful spinal metastases are a common cause of cancer-related morbidity. Percutaneous ablation presents an attractive minimally invasive alternative to conventional therapies. We performed a retrospective review of 69 patients with 102 painful spinal metastases undergoing microwave ablation and cementoplasty to determine the efficacy and safety of this treatment.

MATERIALS AND METHODS

Procedures were performed between January 2015 and October 2016 with the patient under general anesthesia using image guidance for 102 spinal metastases in 69 patients in the following areas: cervical (n = 2), thoracic (n = 50), lumbar (n = 34), and sacral (n = 16) spine. Tumor pathologies included the following: multiple myeloma (n = 10), breast (n = 27), lung (n = 12), thyroid (n = 6), prostate (n = 5), colon (n = 4), renal cell (n = 3), oral squamous cell (n = 1), and adenocarcinoma of unknown origin (n = 1). Procedural efficacy was determined using the visual analog scale measured preprocedurally and at 2-4 weeks and 20-24 weeks postprocedure. Tumor locoregional control was assessed on follow-up cross-sectional imaging. Procedural complications were recorded to establish the safety profile.

RESULTS

The median ablation time was 4 minutes 30 seconds ± 7 seconds, and energy dose, 4.1 ± 1.6 kJ. Median visual analog scale scores were the following: 7.0 ± 1.8 preprocedurally, 2 ± 1.6 at 2-4 weeks, and 2 ± 2.1 at 20-24 weeks. Eight patients died within 6 months following the procedure. Follow-up imaging in the surviving patients at 20-24 weeks demonstrated no locoregional progression in 59/61 patients. Two complications were documented (S1 nerve thermal injury and skin burn).

CONCLUSIONS

Microwave ablation is an effective and safe treatment technique for painful spinal metastases. Further studies may be helpful in determining the role of microwave ablation in locoregional control of metastases.

Virtual Reality in Neurointervention

OBJECTIVES

Virtual reality (VR) allows users to experience realistic, immersive 3D virtual environments with the depth perception and binocular field of view of real 3D settings. Newer VR technology has now allowed for interaction with 3D objects within these virtual environments through the use of VR controllers. This technical note describes our preliminary experience with VR as an adjunct tool to traditional angiographic imaging in the preprocedural workup of a patient with a complex pseudoaneurysm.

METHODS

Angiographic MRI data was imported and segmented to create 3D meshes of bilateral carotid vasculature. The 3D meshes were then projected into VR space, allowing the operator to inspect the carotid vasculature using a 3D VR headset as well as interact with the pseudoaneurysm (handling, rotation, magnification, and sectioning) using two VR controllers.

RESULTS

3D segmentation of a complex pseudoaneurysm in the distal cervical segment of the right internal carotid artery was successfully performed and projected into VR. Conventional and VR visualization modes were equally effective in identifying and classifying the pathology. VR visualization allowed the operators to manipulate the dataset to achieve a greater understanding of the anatomy of the parent vessel, the angioarchitecture of the pseudoaneurysm, and the surface contours of all visualized structures.

CONCLUSION

This preliminary study demonstrates the feasibility of utilizing VR for preprocedural evaluation in patients with anatomically complex neurovascular disorders. This novel visualization approach may serve as a valuable adjunct tool in deciding patient-specific treatment plans and selection of devices prior to intervention.

Image guided percutaneous spine procedures using an optical see-through head mounted display: proof of concept and rationale

BACKGROUND AND PURPOSE

Optical see-through head mounted displays (OST-HMDs) offer a mixed reality (MixR) experience with unhindered procedural site visualization during procedures using high resolution radiographic imaging. This technical note describes our preliminary experience with percutaneous spine procedures utilizing OST-HMD as an alternative to traditional angiography suite monitors.

METHODS

MixR visualization was achieved using the Microsoft HoloLens system. Various spine procedures (vertebroplasty, kyphoplasty, and percutaneous discectomy) were performed on a lumbar spine phantom with commercially available devices. The HMD created a real time MixR environment by superimposing virtual posteroanterior and lateral views onto the interventionalist's field of view. The procedures were filmed from the operator's perspective. Videos were reviewed to assess whether key anatomic landmarks and materials were reliably visualized. Dosimetry and procedural times were recorded. The operator completed a questionnaire following each procedure, detailing benefits, limitations, and visualization mode preferences.

RESULTS

Percutaneous vertebroplasty, kyphoplasty, and discectomy procedures were successfully performed using OST-HMD image guidance on a lumbar spine phantom. Dosimetry and procedural time compared favorably with typical procedural times. Conventional and MixR visualization modes were equally effective in providing image guidance, with key anatomic landmarks and materials reliably visualized.

CONCLUSION

This preliminary study demonstrates the feasibility of utilizing OST-HMDs for image guidance in interventional spine procedures. This novel visualization approach may serve as a valuable adjunct tool during minimally invasive percutaneous spine treatment.

Treatment of hemorrhagic head and neck lesions by direct puncture and n-BCA embolization

Life-threatening bleeding in the head and neck region requires urgent management. These hemorrhagic lesions, for example, a ruptured pseudoaneurysm, are often treated by transarterial embolization (TAE), but prior intervention or surgery, inflammation, anatomic variants, and vessel tortuosity may render an endovascular approach challenging, time-consuming, and sometimes impossible. We report two cases of severe head and neck hemorrhages successfully embolized with n-butyl cyanoacrylate via direct puncture, and propose this approach as a fast, safe, and effective alternative to TAE.

Treatment of hemorrhagic head and neck lesions by direct puncture and nBCA embolization

Life-threatening bleeding in the head and neck region requires urgent management. These hemorrhagic lesions, for example, a ruptured pseudoaneurysm, are often treated by transarterial embolization (TAE), but prior intervention or surgery, inflammation, anatomic variants, and vessel tortuosity may render an endovascular approach challenging, time-consuming, and sometimes impossible. We report two cases of severe head and neck hemorrhages successfully embolized with n-butyl cyanoacrylate via direct puncture, and propose this approach as a fast, safe, and effective alternative to TAE.

Onset of adreno-leukodystrophy after medulloblastoma therapy: causal connection or coincidence?

X-linked adreno-leukodystrophy (ALD) is a peroxisomal disorder affecting the white matter of the central nervous system and the adrenal cortex. It is caused by mutations in the ABCD1 gene encoding for a peroxisomal membrane protein. The absent genotype-phenotype correlation implies a contribution by environmental factors to explain the phenotypical heterogeneity. We report on a 4-year-old boy with a biochemically confirmed diagnosis of ALD after birth. At the age of 32 months, the additional diagnosis of a medulloblastoma was made. After treatment of the medulloblastoma, he developed active areas of demyelination representing the characteristic neuroimaging features of ALD. The clinical history of our patient supports the hypothesis that external factors, like neurosurgical intervention as part of medulloblastoma treatment, may accelerate or initiate cerebral ALD-related demyelination. A postsurgical inflammatory reaction may facilitate the inclusion of abnormal fatty acids in myelin. The opening of the blood-brain barrier following neurosurgery may enhance the recognition of previously sequestered antigens considered to play a role in ALD onset. Consequently, neurosurgical disruption of the BBB can precipitate the immune-mediated inflammatory process, which progressively destroys myelin in ALD patients. Tumor-related chemotherapy and/or radiotherapy may also play a contributing role. We suggest that X-ALD patients who undergo neurosurgical intervention need close follow-up imaging to identify active demyelination early.

Effectiveness of four different clinical fMRI paradigms for preoperative regional determination of language lateralization in patients with brain tumors

INTRODUCTION

Blood oxygen level-dependent functional magnetic resonance imaging (fMRI) has demonstrated its capability to provide comparable results to gold standard intracarotid sodium amobarbital (Wada) testing for preoperative determination of language hemispheric dominance. However, thus far, no consensus has been established regarding which fMRI paradigms are the most effective for the determination of hemispheric language lateralization in specific categories of patients and specific regions of interest (ROIs).

METHODS

Forty-one brain tumor patients who performed four different language tasks-rhyming (R), silent word generation (SWG) sentence completion, and sentence listening comprehension (LC)-for presurgical language mapping by fMRI were included in this study. A statistical threshold-independent lateralization index (LI) was calculated and compared among the paradigms in four different ROIs for language activation: functional Broca's (BA) and Wernicke's areas (WA) as well as larger anatomically defined expressive (EA) and receptive (RA) areas.

RESULTS

The two expressive paradigms evaluated in this study are very good lateralizing tasks in expressive language areas; specifically, a significantly higher mean LI value was noted for SWG (0.36 ± 0.25) compared to LC (0.16 ± 0.24, p = 0.009) and for R (0.40 ± 0.22) compared to LC (0.16 ± 0.24, p = 0.001) in BA. SWG LI (0.28 ± 0.19) was higher than LC LI (0.12 ± 0.16, p = 0.01) also in EA. No significant differences in LI were found among these paradigms in WA or RA.

CONCLUSIONS

SWG and R are sufficient for the determination of lateralization in expressive language areas, whereas new semantic or receptive paradigms need to be designed for an improved assessment of lateralization in receptive language areas.

Baseline cardiovascular risk predicts subsequent changes in resting brain function

BACKGROUND AND PURPOSE

The Framingham Heart Study group cardiovascular disease risk profile (FCRP) score was used to assess the relationship between baseline cardiovascular risk and subsequent changes in resting state cerebral blood flow (CBF) in cognitively normal older participants from the Baltimore Longitudinal Study of Aging.

METHODS

Ninty-seven cognitively normal participants underwent annual resting-state positron emission tomography scans at baseline and over a period of up to 8 years (mean interval, 7.4 years). Images quantifying voxel-wise longitudinal rates of CBF change were calculated and used to examine the relationship between baseline FCRP score and changes over time in regional CBF. Individual components of the FCRP score (age, cholesterol, blood pressure, smoking status, and type 2 diabetes) were also correlated with changes in regional CBF to examine the independent contributions of each component to the overall pattern of change.

RESULTS

Higher baseline FCRP scores were associated with accelerated longitudinal decline in CBF in orbitofrontal, medial frontal/anterior cingulate, insular, precuneus, and brain stem regions. Of the components that comprise the FCRP score, higher diastolic blood pressure and diabetes were associated independently with greater decline in the medial frontal/anterior cingulate and insular regions, respectively.

CONCLUSIONS

Baseline cardiovascular risk factors are associated with greater rates of decline in resting state regional brain function. The regions showing accelerated decline participate in higher-order cognitive processes and are also vulnerable to age-related neuropathology. These results, in conjunction with other studies, encourage early treatment of cardiovascular risk factors in older individuals.