Rate Of Atrophy Research Articles

ReMiND: Recovery of missing neuroimaging using diffusion models with application to Alzheimer’s disease

Abstract Missing data is a significant challenge in medical research. In longitudinal studies of Alzheimer’s disease (AD) where structural magnetic resonance imaging (MRI) is collected from individuals at multiple time points, participants may miss a study visit or drop out. Additionally, technical issues such as participant motion in the scanner may result in unusable imaging data at designated visits. Such missing data may hinder the development of high-quality imaging-based biomarkers. To address the problem of missing MRI data in studies of AD, we introduced a novel 3D diffusion model specifically designed for imputing missing structural MRI (Recovery of Missing Neuroimaging using Diffusion models (ReMiND)). The model generates a whole-brain image conditional on a single structural MRI observed at a past visit or conditional on one past and one future observed structural MRI relative to the missing observation. The performance of models was compared with two alternative imputation approaches: forward filling and image generation using variational autoencoders. Experimental results show that our method can generate 3D structural MRI with high similarity to ground-truth images at designated visits. Furthermore, images generated using ReMiND show relatively lower differences in volume estimation between the imputed and observed images compared to images generated by forward filling or autoencoders. Additionally, ReMiND provides more accurate estimated rates of atrophy over time in important anatomical brain regions than the two comparator methods. Our 3D diffusion model can impute missing structural MRI data at a single designated visit and outperforms alternative methods for imputing whole-brain images that are missing from longitudinal trajectories.

Associations between accelerated forgetting, amyloid deposition and brain atrophy in older adults.

Accelerated long-term forgetting (ALF) is the phenomenon whereby material is retained normally over short intervals (e.g. minutes) but forgotten abnormally rapidly over longer periods (days or weeks). ALF may be an early marker of cognitive decline, but little is known about its relationships with preclinical Alzheimer's disease pathology, and how memory selectivity may influence which material is forgotten. We assessed ALF in 'Insight 46', a sub-study of the MRC National Survey of Health and Development (a population-based cohort born during one week in 1946) (n=429; 47% female; assessed aged ∼73 years). ALF assessment comprised visual and verbal memory tests: Complex Figure Drawing and the Face-Name Associative Memory Exam (FNAME). ALF scores were calculated as the percentage of material retained after 7 days, relative to 30 minutes. In 306 cognitively-normal participants, we investigated effects on ALF of β-amyloid pathology (quantified using 18F-Florbetapir-PET, classified as positive/negative) and whole-brain and hippocampal atrophy rate (quantified from serial T1-MRI over ∼2.4 years preceding the ALF assessment), as well as interactions between these pathologies. We categorized Complex Figure Drawing items as 'outline' or 'detail', to test our hypothesis that forgetting the outline of the structure would be more sensitive to the effect of brain pathologies. We also investigated associations between ALF and Subjective Cognitive Decline, measured with the MyCog questionnaire. Complex Figure 'outline' items were better retained than 'detail' items (mean retention over 7 days = 94% vs 72%). Amyloid-positive participants showed greater forgetting of the Complex Figure outline, compared to amyloid-negatives (90% vs 95%; P<0.01). There were interactions between amyloid pathology and cerebral atrophy, such that whole-brain and hippocampal atrophy predicted greater ALF on Complex Figure Drawing among amyloid-positives only (e.g. 1.9 percentage-points lower retention per ml/year of whole-brain atrophy [95% confidence intervals 0.5, 3.7]; P<0.05). Greater ALF on FNAME was associated with increased rate of hippocampal atrophy. ALF on Complex Figure Drawing also correlated with subjective cognitive decline (-0.45 percentage-points per MyCog point [-0.85, -0.05], P<0.05). These results provide evidence of associations between some measures of ALF and biomarkers of brain pathologies and subjective cognitive decline in cognitively-normal older adults. On Complex Figure Drawing, 'outline' items were better remembered than 'detail' items - illustrating the strategic role of memory selectivity - but 'outline' items were also relatively more vulnerable to ALF in individuals with amyloid pathology. Overall, our findings suggest that ALF may be a sensitive marker of cognitive changes in preclinical Alzheimer's disease.

Spectris™ treatment preserves corpus callosum structure in Alzheimer's disease.

To examine the impact of 40Hz gamma stimulation on the preservation of the corpus callosum, a critical structure for interhemispheric connectivity, in people with mild cognitive impairment or Alzheimer's disease. OVERTURE (NCT03556280) participants were randomized 2:1 (Active:Sham) to receive daily, 1-h, 40Hz gamma sensory stimulation or sham treatment for 6 months. Structural magnetic resonance imaging data were analyzed to assess changes in corpus callosum area (N = 50; 33 for active, 17 for sham). Bayesian linear mixed-effects modeling was used to assess differences in longitudinal changes of corpus callosum area between the two treatment groups. All observed differences in corpus callosum area favored the active treatment group. Differences were observed in the total corpus callosum area (2.28 ± 0.87%, p < 0.02) and its subregions, including genu/rostrum (2.36 ± 0.90%, p < 0.02), anterior-body (2.64 ± 1.26%, p < 0.04), mid-body (2.79 ± 1.18%, p < 0.03), posterior-body (2.87 ± 1.41%, p < 0.05), and splenium (1.58 ± 0.73%, p < 0.04). Total corpus callosum area and some of the sub-regional differences, such as genu/rostrum and splenium, were observed as early as 3 months after commencement of treatment. The structural magnetic resonance imaging results from the OVERTURE Phase 2 study suggest that 6 months of non-invasive 40Hz stimulation reduces the rate of atrophy of the corpus callosum in individuals with Alzheimer's disease. The preservation of structural integrity in the corpus callosum, crucial for interhemispheric communication and cognitive function, may be achievable through this non-invasive approach, potentially providing a promising disease-modifying alternative in Alzheimer's disease management.

Exploring the effects of COVID-19 on verbal memory function in schizophrenia: Multiple case study and brief literature review

Individuals recovering from COVID-19 may experience persistent impairment in verbal memory performance, potentially due to illness-related hippocampal injury. Although verbal memory dysfunction is central to schizophrenia, the interactions between this vulnerability and COVID-19 remain unclear, with no imaging studies addressing the issue to-date. To explore this gap and generate hypotheses for future research, we adopted a multiple case study approach. Two pairs of individuals with an ICD-10 diagnosis of schizophrenia were selected, each consisting of one case with a positive COVID-19 anamnesis and one without. We calculated the Reliable Change Index to estimate the clinical significance of verbal memory performance changes, with annualized change rates in hippocampal volumes assessed against normative data. Compared to their matches, COVID-19 positive cases did not show mutually consistent changes in verbal memory performance: one case experienced a significant decline in verbal memory and learning, while the other showed a general normalization of test scores. Left hippocampal volumes showed a comparatively slowed increase, while the right hippocampi decreased in volume, although these atrophy rates did not exceed those expected in general population samples. Based on these findings, we hypothesize that COVID-19 alone does not lead to verbal memory decline in schizophrenia. Instead, the relationship between the diseases may depend on additional factors. Our case pairs differed in body mass index, systolic blood pressure, sex, phase of illness, and whole grey matter volume trajectories, leading us to hypothesize that these variables represent additional predictors or moderators of this relationship.

Dynamics of choroid plexus volume is associated with the presence and development of fatigue in multiple sclerosis

BackgroundImmune-mediated processes are implicated in the pathogenesis of fatigue, a common symptom in multiple sclerosis (MS). The choroid plexus (CP) regulates central nervous system (CNS) immune homeostasis and undergoes volumetric...

Super-Resolution in Clinically Available Spinal Cord MRIs Enables Automated Atrophy Analysis.

Measurement of the mean upper cervical cord area (MUCCA) is an important biomarker in the study of neurodegeneration. However, dedicated high-resolution scans of the cervical spinal cord are rare in standard-of-care imaging due to timing and clinical usability. Most clinical cervical spinal cord imaging is sagittally acquired in 2D with thick slices and anisotropic voxels. As a solution, previous work describes high-resolution T1-weighted brain imaging for measuring the upper cord area, but this is still not common in clinical care. We propose using a zero-shot super-resolution technique, SMORE, already validated in the brain, to enhance the resolution of 2D-acquired scans for upper cord area calculations. To incorporate super-resolution in spinal cord analysis, we validate SMORE against high-resolution research imaging and in a real-world longitudinal data analysis. Super-resolved images reconstructed using SMORE showed significantly greater similarity to the ground truth than low-resolution images across all tested resolutions (p<0.001 for all resolutions in PSNR and MSSIM). MUCCA results from super-resolved scans demonstrate excellent correlation with high-resolution scans (r>0.973 for all resolutions) compared to low-resolution scans. Additionally, super-resolved scans are consistent between resolutions (r>0.969), an essential factor in longitudinal analysis. Compared to clinical outcomes such as walking speed or disease severity, MUCCA values from low-resolution scans have significantly lower correlations than those from high-resolution scans. Super-resolved results have no significant difference. In a longitudinal real-world dataset, we show that these super-resolved volumes can be used in conjunction with T1-weighted brain scans to show a significant rate of atrophy (-0.790, p=0.020 vs. -0.438, p=0.301 with low-resolution). Super-resolution is a valuable tool for enabling large-scale studies of cord atrophy, as low-resolution images acquired in clinical practice are common and available. MS=multiple sclerosis; MUCCA=mean upper cervical cord; HR=high-resolution; LR=low-resolution; SR=superresolved; CSC=cervical spinal cord; PMJ=pontomedullary junction; MSSIM=mean structural similarity; PSNR=peak signal-to-noise ratio; EDSS=expanded disability status scale.

Impact of insurance status on MRI phenotypes in MS

BackgroundHealth insurance in the United States varies in coverage of essential diagnostic tests, therapies, and specialists. Health disparities between privately and publicly insured patients with MS have not been comprehensively assessed. The objective of this study is to evaluate the impact of public versus private insurance on longitudinal brain outcomes in MS. MethodsLesional, thalamic, and gray and white matter volumes were extracted from longitudinal MRI of 710 MS patients. Baseline volumes and atrophy rates of lesional, thalamic, and gray and white matter volumes were compared across insurance groups. ResultsAfter image quality assessment, 376 (284 private / 92 public), 638 (499 / 139), and 331 (250 / 81), patients were in MS lesion, thalamic, gray and white matter analyses respectively. Baseline lesion volume was higher for publicly insured patients but increased at a slightly higher rate in those privately insured (p = 0.01). Baseline gray matter measurements were lower for patients with public insurance, but thalamic (p < 0.01) and gray matter (p < 0.01) atrophy rates were slightly higher in the private insurance group. ConclusionInsurance type was associated with lesion, thalamic, and gray matter volumes. The results suggest that patients with public insurance may present with more advanced disease.

Differential correlations of changes in in vivo neuroimaging markers of hippocampal volume and arteriolosclerosis with declining financial and health literacy in old age.

Financial and health literacy is essential for older adults to navigate complex decision processes in late life. However, the neurobiological basis of age-related decline in financial and health literacy is poorly understood. This study aimed to characterize progression of neurodegenerative and vascular conditions over time, and to assess how these changes coincide with declining financial and health literacy in old age. Data came from 319 community-living older adults who were free of dementia at baseline, and underwent annual literacy assessments, as well as biennial 3-Tesla neuroimaging scans. Financial and health literacy was assessed using a battery of 32 items. Two in vivo neuroimaging markers of neurodegenerative and cerebrovascular conditions were used, i.e., hippocampal volume and the ARTS marker of arteriolosclerosis. A multivariate linear mixed effects model estimated the simultaneous changes in financial and health literacy, hippocampal volume, and the ARTS score. Over a mean of 7 years of follow-up, these older adults experienced a significant decline in financial and health literacy, a significant reduction in hippocampal volume, and a significant progression in ARTS score. Individuals with faster hippocampal atrophy had faster decline in literacy. Similarly, those with faster progression in ARTS also had faster decline in literacy. The correlation between the rates of hippocampal atrophy and declining literacy, however, was stronger than the correlation between the progression of ARTS with declining literacy. These findings suggest that neurodegeneration and, to a lesser extent, cerebrovascular conditions are correlated with declining financial and health literacy in old age.

Impact of high-protein enteral nutrition on muscle preservation in mechanically ventilated patients with severe pneumonia: a randomized controlled trial.

This study aimed to assess the effects of enteral nutrition with different protein concentrations on muscle mass in severe pneumonia patients, providing insights for enteral nutrition practice in intensive care units (ICUs). A total of 120 severe pneumonia patients admitted to Dazhou Central Hospital's ICU between June 1, 2022, and February 1, 2023, meeting inclusion criteria, were randomly assigned to either a high-protein group (n = 60, 1.8g/kg/d) or a standard-protein group (n = 60, 1.2g/kg/d). Changes in relevant indicators were monitored on days 1, 5, and 10 of ICU admission, including quadriceps and diaphragm thickness, nutritional status (prealbumin and albumin), and adverse events such as diarrhea and constipation. Autoregressive of order 1 model (AR(1)) analysis revealed a decrease in both quadriceps and diaphragm thickness over time in both groups. A significant group × time interaction was observed in quadriceps thickness. By day 10, compared to baseline, quadriceps thickness decreased in the high-protein (-0.315cm [95% CI, -0.340 to -0.289]) and standard-protein (-0.429cm [95% CI, -0.455 to -0.404]) groups. The high-protein group exhibited a lower quadriceps atrophy rate (13.97 ± 2.43%) compared to the standard-protein group (18.96 ± 2.61%), showing a significant difference (P < 0.001). No significant differences were found in diaphragmatic thickness between groups and over time. By day 10, both groups exhibited decreased diaphragmatic muscle thickness compared to baseline. The high-protein group (33.76 ± 5.09%) had a slightly lower phrenic atrophy rate compared to the standard-protein group (33.41 ± 4.53%). Both groups experienced enteral nutritional intolerance manifested as diarrhea, constipation, and other adverse events. High-protein enteral nutrition significantly improved quadriceps thickness and demonstrated good safety in severe pneumonia patients, suggesting its suitability for widespread clinical application.

Feasibility and effectiveness of a foam rolling intervention in pregnant women requiring bed rest for foetal protection: a randomised controlled trial

BackgroundBed rest during pregnancy can lead to reduced physical activity, impairing lower limb venous blood flow and increasing the risk of deep vein thrombosis (DVT) and muscle atrophy. We investigated the clinical efficacy of foam rolling intervention (FRI) in enhancing lower limb venous blood flow, mitigating the risk of DVT and muscle atrophy in pregnant women on bed rest.MethodsThis single-blind, randomised controlled trial enrolled 86 pregnant women with long-term bed rest for foetal protection (≥ 7 days), gestational age ≥ 20 weeks, and maternal age < 40 years. Participants were randomly assigned to a control or experimental group using a random number table. The control group received standard care, whereas the experimental group underwent FRI. Researchers and statisticians were aware of the treatment groups, however, the participants were blinded. Lower limb blood flow velocity, D-dimer levels, incidence of DVT, and the extent of lower limb muscle atrophy were assessed in both groups at baseline and post-intervention (day 7). To account for a 5% attrition rate and potential sampling error, the estimated sample size for each experimental and control group was 40.ResultsBefore the intervention, no significant differences were observed between the experimental and control groups in peak blood flow, mean flow velocity, D-dimer values, or leg circumference (P > 0.05), however, the peak blood velocities of the popliteal veins were significantly higher in the control group (P = 0.031). On the seventh day post-intervention, the experimental group had significantly higher mean and peak blood velocities in femoral and popliteal veins, significantly (P < 0.05), lower mean D-dimer levels (P = 0.035), and a significantly smaller reduction in thigh and calf circumference (P < 0.001). Consequently, the rate of thigh muscle atrophy was significantly slower in the experimental group (P = 0.011).ConclusionsFRI is an effective intervention for improving lower limb venous blood flow, mitigating the risk of DVT and muscle atrophy in pregnant women on bed rest.Trial registrationThis trial was retrospectively registered with the Chinese Clinical Trial Registry on June 18, 2024 (registration number: ChiCTR2400085770).

Progressive cervical cord atrophy parallels cognitive decline in Alzheimer’s disease

Alzheimer’s disease (AD) is characterized by progressive episodic memory dysfunction. A prominent hallmark of AD is gradual brain atrophy. Despite extensive research on brain pathology, the understanding of spinal cord pathology in AD and its association with cognitive decline remains understudied. We analyzed serial magnetic resonance imaging (MRI) scans from the ADNI data repository to assess whether progressive cord atrophy is associated with clinical worsening. Cervical cord morphometry was measured in 45 patients and 49 cognitively normal controls (CN) at two time points over 1.5 years. Regression analysis examined associations between cord atrophy rate and cognitive worsening. Cognitive and functional activity performance declined in patients during follow-up. Compared with controls, patients showed a greater rate of decline of the anterior–posterior width of the cross-sectional cord area per month (− 0.12%, p = 0.036). Worsening in the mini-mental state examination (MMSE), clinical dementia rating (CDR), and functional assessment questionnaire (FAQ) was associated with faster rates of cord atrophy (MMSE: r = 0.320, p = 0.037; CDR: r = − 0.361, p = 0.017; FAQ: r = − 0.398, p = 0.029). Progressive cord atrophy occurs in AD patients; its rate over time being associated with cognitive and functional activity decline.

Changes in brain functional connectivity and muscle strength independent of elbow flexor atrophy following upper limb immobilization in young females.

Muscle disuse induces a decline in muscle strength that exceeds the rate and magnitude of muscle atrophy, suggesting that factors beyond the muscle contribute to strength loss. The purpose of this study was to characterize changes in the brain and neuromuscular system in addition to muscle size following upper limb immobilization in young females. Using a within-participant, unilateral design, 12 females (age: 20.6±2.1years) underwent 14days of upper arm immobilization using an elbow brace and sling. Bilateral measures of muscle strength (isometric and isokinetic dynamometry), muscle size (magnetic resonance imaging), voluntary muscle activation capacity, corticospinal excitability, cortical thickness and resting-state functional connectivity were collected before and after immobilization. Immobilization induced a significant decline in isometric elbow flexion (-21.3±19.2%, interaction: P=0.0440) and extension (-19.9±15.7%, interaction: P=0.0317) strength in the immobilized arm only. There was no significant effect of immobilization on elbow flexor cross-sectional area (CSA) (-1.2±2.4%, interaction: P=0.466), whereas elbow extensor CSA decreased (-2.9±2.9%, interaction: P=0.0177) in the immobilized arm. Immobilization did not differentially alter voluntary activation capacity, corticospinal excitability, or cortical thickness (P>0.05); however, there were significant changes in the functional connectivity of brain regions related to movement planning and error detection (P<0.05). This study reveals that elbow flexor strength loss can occur in the absence of significant elbow flexor muscle atrophy, and that the brain represents a site of functional adaptation in response to upper limb immobilization in young females.

Comparison of clinical and radiographic outcomes in unilateral transforaminal lumbar interbody fusion: a retrospective analysis of three surgical approaches.

The primary objective of this study is to evaluate and compare the clinical and radiographic outcomes of the combined spinous process-splitting approach with a Wiltse (SPSW) approach, the combined conventional approach with a Wiltse (CW) approach, and the conventional open (CO) approach in unilateral transforaminal lumbar interbody fusion (TLIF). The clinical outcomes were assessed, and intraoperative data and complications were collected. Numeric Rating Scale (NRS) scores for low back pain and leg pain, the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) scores for evaluating functions of the lumbar spine and health-related quality of life, and the modified MacNab standard for assessing satisfaction were analyzed. Radiographic outcomes included disc space height, segmental lordosis, interbody fusion assessment, and the rate of muscle atrophy of the multifidus and the erector spinae muscles. Among the three groups, the SPSW group exhibited the shortest operation and drain retention time, lowest intraoperative blood loss, and minimal postoperative blood loss. Notably, the SPSW group displayed the highest level of social life function based on the JOABPEQ, and the highest level of patient satisfaction according to the modified MacNab Criteria, along with the lowest rate of muscle atrophy. All the SPSW, CW, and CO approach TLIF procedures achieved overall satisfactory effects of decompression and fusion for lumbar degenerative diseases. The SPSW approach procedure appears to be associated with the smallest surgical trauma and highest satisfaction because of reducing iatrogenic injury of the paraspinal muscles.

Comparative Outcomes of Single-Stage versus Two-Stage Laparoscopic Fowler-Stephens Orchidopexy: A Systematic Review snd Meta-Analysis.

Intra-abdominal testis (IAT) remains a challenging and controversial subset within the management of cryptorchidism. While Fowler-Stephens orchidopexy (FSO) is still being advocated as the gold standard for the treatment of this entity, there is new and conflicting evidence on the comparative outcomes between single- or two-stage laparoscopic FSO (LFSO). The aim of the study is to investigate whether staging has benefits in children receiving LFSO. We searched the PubMed, Medline, Embase, and Cochrane Trials databases for studies comparing single- with two-stage LFSO in children from January 1, 1995 to December 31, 2023. We assessed the identified studies for quality and performed a systematic review and meta-analysis in accordance with the Preferred Reporting of Systematic Reviews and Meta-Analyses. The main outcome measures examined were success rate (in terms of the scrotal position of the testis) and testicular atrophy, which were analyzed using fixed effect models. We included 17 eligible studies that involved a total of 499 operated testes. The overall success rates of single- and two-stage LFSO were 79.4 and 90.3%, respectively. The overall testicular atrophy rates of single- and two-stage LFSO were 17.3 and 11%, respectively. Fixed effect model analysis showed that two-stage LFSO is significantly superior to single-stage LFSO in overall success rate (odds ratio [OR: 2.57]; 95% confidence interval [CI]: 1.50-4.39, p = 0.0006) and testicular atrophy rate (OR: 0.48; 95% CI: 0.28-0.79, p = 0.004). There is no heterogeneity in the reports, and the funnel plot showed no publication bias. Two-stage LFSO remains the first choice of operation for children with a high IAT, with a significantly higher success rate and a lower testicular atrophy rate.

Evaluation of cervical spinal cord atrophy using a modified SIENA approach

Spinal cord (SC) atrophy obtained from structural magnetic resonance imaging has gained relevance as an indicator of neurodegeneration in various neurological disorders. The common method to assess SC atrophy is by comparing numerical differences of the cross-sectional spinal cord area (CSA) between time points. However, this indirect approach leads to considerable variability in the obtained results. Studies showed that this limitation can be overcome by using a registration-based technique.The present study introduces the Structural Image Evaluation using Normalization of Atrophy on the Spinal Cord (SIENA-SC), which is an adapted version of the original SIENA method, designed to directly calculate the percentage of SC volume change over time from clinical brain MRI acquired with an extended field of view to cover the superior part of the cervical SC.In this work, we compared SIENA-SC with the Generalized Boundary Shift Integral (GBSI) and the CSA change. On a scan-rescan dataset, SIENA-SC was shown to have the lowest measurement error than the other two methods. When comparing a group of 190 Healthy Controls with a group of 65 Multiple Sclerosis patients, SIENA-SC provided significantly higher yearly rates of atrophy in patients than in controls and a lower sample size when measured for treatment effect sizes of 50%, 30% and 10%.Our findings indicate that SIENA-SC is a robust, reproducible, and sensitive approach for assessing longitudinal changes in spinal cord volume, providing neuroscientists with an accessible and automated tool able to reduce the need for manual intervention and minimize variability in measurements.

Prevalence, Features, and Outcomes of Type 1 Neovascularization in Eyes with Angioid Streaks

This study aimed to delineate the characteristics, prevalence, and outcomes of neovascularization (NV), particularly aneurysmal Type 1 NV, in patients with angioid streaks (AS) secondary to pseudoxanthoma elasticum (PXE), and to introduce a clinical classification based on multimodal imaging (MMI). Retrospective longitudinal cohort study. 85 patients (168 eyes) with AS secondary to PXE at two tertiary referral centers. Data collection included demographic, medical, and ocular histories. Diagnostic methods comprised fundus photography, autofluorescence, indocyanine green angiography, optical coherence tomography (OCT), and OCT angiography. Prevalence of Type 1 NV, visual acuity (VA), risk of exudation. Type 1 NV was identified in 127 eyes (76%), with 85 of these (67%) showing exclusively Type 1 NV. These lesions often originated around the disc, at sites of Bruch's membrane dehiscences, and followed the path of AS, extending to the posterior pole in 101 eyes (80%). Despite 65% of Type 1 NV remaining non-exudative, 36% evolved into exudative over five years, and 11 eyes experienced mid-peripheral subretinal hemorrhages. Aneurysmal dilations, observed in 57% of cases, substantially increased exudation risk (hazard ratio = 3.86, p=0.02). Despite treatment, VA significantly deteriorated in exudative Type 1 NV (p=0.02). Type 2 NV, detected in 56 eyes (33%), often coexisted with Type 1 NV and was associated with poorer visual outcomes and higher rates of macular atrophy. A classification of AS was developed, ranging from empty AS (stage 0, no NV) to advanced NV (stage 3, both Type 1 and Type 2 NV). Type 1 NV predominates in AS. Although predominantly non-exudative, its progression correlates with substantial visual impairment, similar to the deficits observed with Type 2 NV. Aneurysmal Type 1 NV poses a significant exudation risk, underscoring the need for vigilant monitoring.

Association of Basal Forebrain Atrophy With Cognitive Decline in Early Alzheimer Disease.

In early Alzheimer disease (AD), β-amyloid (Aβ) deposition is associated with volume loss in the basal forebrain (BF) and cognitive decline. However, the extent to which Aβ-related BF atrophy manifests as cognitive decline is not understood. This study sought to characterize the relationship between BF atrophy and the decline in memory and attention in patients with early AD. Participants from the Australian Imaging, Biomarkers and Lifestyle (AIBL) study who completed Aβ-PET imaging and repeated MRI and cognitive assessments were included. At baseline, participants were classified based on their clinical dementia stage and Aβ status, yielding groups that were cognitively unimpaired (CU) Aβ-, CU Aβ+, and mild cognitive impairment (MCI) Aβ+. Linear mixed-effects models were used to assess changes in volumetric measures of BF subregions and the hippocampus and changes in AIBL memory and attention composite scores for each group compared with CU Aβ- participants. Associations between Aβ burden, brain atrophy, and cognitive decline were evaluated and explored further using mediation analyses. The cohort included 476 participants (72.6 ± 5.9 years, 55.0% female) with longitudinal data from a median follow-up period of 6.1 years. Compared with the CU Aβ- group (n = 308), both CU Aβ+ (n = 107) and MCI Aβ+ (n = 61) adults showed faster decline in BF and hippocampal volumes and in memory and attention (Cohen d = 0.73-1.74). Rates of atrophy in BF subregions and the hippocampus correlated with cognitive decline, and each individually mediated the impact of Aβ burden on memory and attention decline. When all mediators were considered simultaneously, hippocampal atrophy primarily influenced the effect of Aβ burden on memory decline (β [SE] = -0.139 [0.032], proportion mediated [PM] = 28.0%) while the atrophy of the posterior nucleus basalis of Meynert in the BF (β [SE] = -0.068 [0.029], PM = 13.1%) and hippocampus (β [SE] = -0.121 [0.033], PM = 23.4%) distinctively influenced Aβ-related attention decline. These findings highlight the significant role of BF atrophy in the complex pathway linking Aβ to cognitive impairment in early stages of AD. Volumetric assessment of BF subregions could be essential in elucidating the relationships between the brain structure and behavior in AD.

Early predictive value of ultrasound measurements of rectus femoris cross-sectional area to diagnose ICU-acquired weakness in patients undergoing invasive mechanical ventilation: a prospective cohort study

BackgroundThe diagnosis of ICU-acquired weakness (ICUAW) may be delayed due to the complexity of critically ill patients. This study aimed to investigate the value of ultrasound measurements of rectus femoris cross-sectional area (RFCSA) in predicting ICUAW in patients undergoing invasive mechanical ventilation.MethodsThis was a prospective cohort study of patients undergoing mechanical ventilation for at least 48 h. RFCSA was measured using ultrasound in patients upon ICU admission and followed until discharge. Using the Medical Research Council score as the gold standard, we evaluated the diagnostic value of ultrasound measurements in predicting ICUAW. Kaplan–Meier curves were constructed to evaluate and compare the length of ICU stay and duration of invasive mechanical ventilation between patients with and without ICUAW.ResultsAmong the 76 patients, 34 (44.7%) were diagnosed with ICUAW using the Medical Research Council score as the gold standard. The RFCSA atrophy rate between day 1 and day 3 was significantly higher in the ICUAW group (7.9 ± 2.8% vs. 4.3 ± 2.1%, p < 0.001). By utilizing a cutoff point of 6.9%, we discovered that the RFCSA atrophy rate exhibited excellent diagnostic accuracy in predicting ICUAW, with a sensitivity of 76.5% and specificity of 92.9%. In ICUAW patients diagnosed based on an RFCSA atrophy rate, the proportion of patients with an ICU stay longer than 14 days was 42.9%, which was significantly higher compared to 22.9% in the non-ICUAW group (HR: 1.768; 95% CI 1.128–2.772; p = 0.006). Similarly, the proportion of patients continuing mechanical ventilation at 14 days was 28.6% versus 4.2% between the two groups (HR: 1.988; 95% CI 1.266–3.120; p < 0.001).ConclusionUltrasound measurements of RFCSA provide a reliable method for diagnosing ICUAW and indicating prognosis in patients undergoing invasive mechanical ventilation.

Optimization of cervical cord synthetic T1-weighted MRI for enhancing clinical application in neurodegenerative spinal cord disorders

Abstract Synthetic MRI offers the advantage of reducing acquisition time and enhancing flexibility through the reconstruction of various contrast weightings from a single set of MRI scans. However, the use of synthetic T1-weighted (synT1-w) MRI can lead to potentially biased measurements of the cross-sectional area (CSA) in the spinal cord when compared to conventionally acquired T1-weighted MRI. This disparity can have implications for comparability and sensitivity of MRI in assessing disease progression or treatment effects in neurodegenerative spinal cord disorders. Thus, this study aimed at improving the accuracy (i.e., difference between synthetic and acquired MRI) of cervical cord CSA measurements (C1-C3 level) based on synT1-w MRI implementing a longitudinal data set acquired from 23 acute spinal cord injury (SCI) patients and 21 healthy controls over 2 years. Moreover, the validity of using synT1-w MRI for tracking cervical cord atrophy following SCI over 2 years was verified. SynT1-w images were reconstructed from quantitative maps of proton density, longitudinal, and effective transverse relaxation rates derived from a multi-parameter mapping protocol. The results showed a minimal bias of -0.31 mm2 (-0.5%) in CSA measurements based on synT1-w compared to acquired MRI. Estimates of atrophy rates and average CSA were comparable between synthetic and acquired MRI. A sample size estimation for detecting treatment effects on CSA atrophy after 2 years following SCI revealed that the required sample size is reduced by 13.5% using synT1-w instead of acquired MRI. This study shows high accuracy of synT1-w MRI and demonstrates its applicability in clinical studies for optimizing long MRI protocols.

Paraspinal Muscle Morphology in Proximal Cervical Spondylotic Amyotrophy.

This is a retrospective analysis of prospectively collected single-center observational data. The aim is to evaluate atrophy and fatty degeneration rates of cervical spinal muscles in proximal cervical spondylotic amyotrophy (PCSA). Proximal cervical spondylotic amyotrophy affects muscles in the upper extremities. In cases that lack improvement with conservative treatment, surgery is recommended. However, preoperative factors associated with poor outcomes remain unclear. We hypothesized that assessing fatty degeneration of the cervical spinal muscles and examining its relationship with functional impairment would help predict postoperative improvement in neurological function. This study included 18 patients who underwent PCSA surgery. We performed selective laminoplasty and foraminotomy. Preoperative paraspinal muscle cross-sectional area and fatty degeneration were quantified and correlated with neurological function. Neurological improvement based on manual muscle testing was observed in 12/18 patients, comparing preoperative, perioperative, and over 12-month postoperative statuses. On the affected side, at the C4/5 level, fatty degeneration was more significant in the trapezius, whereas at the C5/6 level, fatty degeneration was more significant in the splenius capitis and trapezius. The fatty degeneration of the C4/5 and C5/6 trapezius was significantly correlated with preoperative muscle strength and postoperative muscle strength improvement. The degree of fat infiltration of the muscle correlated with pre- and postoperative muscle strength at the lesion level. Thus, our results suggest a relationship between cervical muscle morphology and the clinical manifestations of PCSA. The marked increase in trapezius fatty infiltration at the C4/5 and C5/6 levels may be a valuable indicator to predict poor improvements in postoperative muscle strength.