Magnetic Resonance Imaging Scans Research Articles

Neural Correlates of Retrieval Success and Precision: A Functional Magnetic Resonance Imaging Study.

Prior studies examining the neural mechanisms underlying retrieval success and precision have yielded inconsistent results. Here, the neural correlates of success and precision were examined with a memory task that assessed precision for spatial location. A sample of healthy young adults underwent functional magnetic resonance imaging scanning during a single study-test cycle. At study, participants viewed a series of object images, each placed at a randomly selected location on an imaginary circle. At test, studied images were intermixed with new images and presented to the participants. The requirement was to move a cursor to the location of the studied image, guessing if necessary. Participants then signaled whether the presented image had been studied. Memory precision was quantified as the angular difference between the studied location and the location selected by the participant. A precision effect was evident in the left angular gyrus, where BOLD activity covaried with location accuracy. In addition, multivoxel pattern analysis revealed a significant item-level reinstatement effect in the angular gyrus for high-precision trials. There was no evidence of a retrieval success effect in this region. BOLD activity in the hippocampus was insensitive to both success and precision. These findings are partially consistent with prior evidence that success and precision are dissociable features of memory retrieval.

Characteristics of Supercritical CO2 Non-Mixed Phase Replacement in Intraformational Inhomogeneous Low-Permeability Reservoirs

Under the influence of the sedimentation process, the phenomenon of intraformational non-homogeneity is widely observed in low-permeability reservoirs. In the development process of water and gas replacement (WAG), the transport law of water and gas and the distribution of residual oil are seriously affected by the non-homogeneity of reservoir properties. In this paper, a study on two types of reservoirs with certain lengths and thicknesses is carried out, and a reasonable development method is proposed according to the characteristics of each reservoir. Firstly, through indoor physical simulation experiments combined with low-field nuclear magnetic resonance scanning (NMR), this study investigates the influence of injection rate and core length on the double-layer low-permeability inhomogeneous core replacement and pore throat mobilization characteristics. Then, a two-layer inhomogeneous low-permeability microscopic model is designed to investigate the model’s replacement and pore throat mobilization characteristics under the combined influence of rhythmites, gravity, the injection rate, etc. Finally, based on the results of the core replacement and numerical simulation, a more reasonable development method is proposed for each type of reservoir. The results show that for inhomogeneous cores of a certain length, the WAG process can significantly increase the injection pressure and effectively seal the high-permeability layer through the Jamin effect to improve the degree of recovery. Moreover, for positive and reverse rhythm reservoirs of a certain thickness, the injection rate can be reduced according to the physical properties of the reservoir, and the gravity overburden phenomenon of the gas is used to achieve the effective development of the upper layers. The effect of the development of a positive rhythm reservoir therefore improved significantly. These findings provide data support for improving the development effectiveness of CO2 in low-permeability inhomogeneous reservoirs and emphasize the importance of the influence of multiple factors, such as injection flow rate, gravity, and rhythm, in CO2 replacement.

Transfer Learning Approaches for Brain Metastases Screenings.

In this study, we examined the effectiveness of transfer learning in improving automatic segmentation of brain metastases on magnetic resonance imaging scans, with potential applications in preventive exams and remote diagnostics. We trained three deep learning models on a public dataset from the ASNR-MICCAI Brain Metastasis Challenge 2024, fine-tuned them on a small private dataset, and compared their performance to models trained from scratch. Results showed that models using transfer learning performed better than scratch-trained models, though the improvement was not statistically substantial. The custom Tversky and Binary Cross-Entropy loss function helped manage class imbalance and reduce false negatives, limiting missed tumor regions. Medical experts noted that, while fine-tuned models worked well with larger, well-defined tumors, they struggled with tiny, scattered tumors in complex cases. This study highlights the potential of transfer learning and tailored loss functions in medical imaging, while also pointing out the models' limitations in detecting very small tumors in challenging cases.

The relationship between glenoid osteometry and recurrent anterior glenohumeral instability

The most common joint to dislocate is the glenohumeral joint, resulting in chronic pain and limited function. The role of the capsuloligamentous structures and muscle balance in contributing to shoulder stability has been well documented in the literature but the case is not the same for the bony anatomy of the glenoid. There is limited data on the contribution of glenoid osteometry in increasing the risk of anterior shoulder dislocation. This study sought to find out the association between anterior glenohumeral instability and glenoid anteversion/inclination. A retrospective, case-control study was carried out. The study was carried out at the Departments of Radiology and Imaging at two university hospitals. Shoulder Magnetic Resonance Imaging (MRI) scans for 45 patients aged between 18 to 45 years with recurrent anterior shoulder instability were used in the study and compared with a control consisting of shoulder MRIs of 45 patients with other shoulder pathologies but having no incidences of dislocation. A structured data collection tool was used to collect the data. Data was analyzed using Statistical Package for the Social Sciences (SPSS) version 26. The mean age for all the participants was 32.0 (SD 9.0) years. The mean age for the cases was 29.0 (SD 8.7) years, while for the controls was 34.6 (SD 8.5) years. The glenoid was anteverted in 40% and 35.6% of cases and controls respectively (p = 1.00) and retroverted in 60% and 64.4% of cases and controls respectively (p =0.666). Most of the glenoids were superiorly inclined (91.1% and 93.3% for cases and controls respectively. The differences in the glenoid version and inclination between the cases and controls were not statistically significant (p = 0.288 and p = 0.489 for the glenoid version and inclination respectively. Glenoid version and inclination are not significantly increased in patients with anterior shoulder instability compared to unmatched controls.

Focal classic intradural extramedullary ependymoma near the conus medullaris: A case report and literature review

Rationale: To enhance clinicians’ comprehension of conus medullaris region ependymomas and elevate their diagnostic accuracy. Patient concerns: A 26-year-old female patient had 10 months of low back pain and right lower limb pain. Diagnoses: Lumbar magnetic resonance imaging (MRI) scan revealed a circular abnormal signal in the spinal canal at the level of L2. Pathological examination confirmed classic ependymoma. Interventions: The patient underwent tumor resection surgery. Outcomes: Postoperatively, the patient’s right lower limb soreness improved, and no new neurological deficits were observed. Lessons: Focal classic intradural extramedullary ependymomas near the conus medullaris are rare. Close follow-up with MRI of the craniospinal axis is necessary. Hormonal factors may influence the development of ependymomas in this unusual location. The appearance of these tumors on MRI and contrast-enhanced MRI scans is variable.

Case Report: Multi drug resistant tuberculosis in an 18-month-old boy with seizure, vomiting, and loss of vision

Multi drug resistant tuberculosis (MDR-TB) in children is rare and requires tremendous skill and knowledge of clinicians for early detection and treatment. This case highlights the complexities in diagnosing and treating MDR-TB in young children. An 18-month-old immunocompetent boy presented with prolonged fever, sudden onset of vision loss, vomiting, and seizures, which led to a suspicion of meningitis. Given his family history of treated pulmonary TB (TB) in the father and uncle one year ago, the initial treatment followed the Nepali national protocol for non-MDR tuberculous meningitis (TBM). However, the child's lack of response to this treatment raised concerns about MDR-TB, particularly after discovering on close questioning that the uncle, who lived with the boy’s family, had actually been diagnosed with MDR-TB. The diagnosis was confirmed by molecular tests of cerebrospinal fluid (CSF) and customized treatment for MDR TBM administered. The boy then slowly improved and became less irritable, afebrile, seizure-free, developed spontaneous movements of all four limbs, and was discharged after one month. Delays in suspicion, confirmation, and treatment of MDR TBM led to complications of leptomeningitis with non-communicating hydrocephalus and bilateral optic atrophy, which was confirmed by magnetic resonance imaging (MRI) scan of the brain. This case highlights the importance of taking a very thorough and proper history and considering the possibility of MDR, especially in countries like Nepal where TB in general is rampant so that timely diagnosis and treatment is possible and complications are avoided.

CNN-based glioma detection in MRI: A deep learning approach.

More than a million people are affected by brain tumors each year; high-grade gliomas (HGGs) and low-grade gliomas (LGGs) present serious diagnostic and treatment hurdles, resulting in shortened life expectancies. Glioma segmentation is still a significant difficulty in clinical settings, despite improvements in Magnetic Resonance Imaging (MRI) and diagnostic tools. Convolutional neural networks (CNNs) have seen recent advancements that offer promise for increasing segmentation accuracy, addressing the pressing need for improved diagnostic and therapeutic approaches. The study intended to develop an automated glioma segmentation algorithm using CNN to accurately identify tumor components in MRI images. The goal was to match the accuracy of experienced radiologists with commercial instruments, hence improving diagnostic precision and quantification. 285 MRI scans of high-grade gliomas (HGGs) and low-grade gliomas (LGGs) were analyzed in the study. T1-weighted sequences were utilised for segmentation both pre-and post-contrast agent administration, along with T2-weighted sequences (with and without Fluid Attenuation by Inversion Recovery [FAIRE]). The segmentation performance was assessed with a U-Net network, renowned for its efficacy in medical image segmentation. DICE coefficients were computed for the tumour core with contrast enhancement, the entire tumour, and the tumour nucleus without contrast enhancement. The U-Net network produced DICE values of 0.7331 for the tumour core with contrast enhancement, 0.8624 for the total tumour, and 0.7267 for the tumour nucleus without contrast enhancement. The results align with previous studies, demonstrating segmentation accuracy on par with professional radiologists and commercially accessible segmentation tools. The study developed a CNN-based automated segmentation system for gliomas, achieving high accuracy in recognising glioma components in MRI images. The results confirm the ability of CNNs to enhance the accuracy of brain tumour diagnoses, suggesting a promising avenue for future research in medical imaging and diagnostics. This advancement is expected to improve diagnostic processes for clinicians and patients by providing more precise and quantitative results.

Giant Cell Tumor of Capitate with Secondary Aneurysmal Bone Cyst: A Case Report

Abstract Background Giant cell tumors (GCTs) of the carpal bones are rare. GCTs of the hand tend to be aggressive, could result in multifocal presentation, and have a high rate of recurrence. Case Description We report a rare case of GCT of the capitate with secondary aneurysmal bone cyst (ABC) in a 40-year-old man. The patient presented with complaints of pain and swelling over his right wrist since 6 months. Radiographs showed the presence of a lytic lesion in the capitate. Magnetic resonance imaging scanning revealed a well-defined, lobulated, multiseptate lytic lesion involving the entire capitate, extending into its subarticular regions. Fine-needle aspiration revealed findings suggestive of a GCT. He underwent en-bloc excision of the capitate, bone grafting of the defect using an appropriately sized bicortical iliac crest autograft, and third carpometacarpal and midcarpal fusion. Histopathological examination of the lesion confirmed the presence of a GCT, with a secondary ABC. At 3 years following surgery, he was asymptomatic with no signs of tumor recurrence, radiocarpal arthritis, or instability. He was able to perform 45 and 60 degrees of wrist extension and flexion, respectively. Literature Review To our knowledge, there are no prior reported cases of GCT of the capitate with a secondary ABC. Clinical Relevance GCTs of the hand in general have a high rate of recurrence. The presence of a super-added ABC could further increase this risk. In the authors' opinion, en-bloc excision of the affected bone, reconstruction of the defect, and appropriate fusion is the optimal mode of management of these cases.

Lifetime brain atrophy estimated from a single MRI: measurement characteristics and genome-wide correlates.

A measure of lifetime brain atrophy (LBA) obtained from a single magnetic resonance imaging (MRI) scan could be an attractive candidate to boost statistical power in uncovering novel genetic signals and mechanisms of neurodegeneration. We analysed data from five young and old adult cohorts (MRi-Share, Human Connectome Project, UK Biobank, Generation Scotland Subsample, and Lothian Birth Cohort 1936 [LBC1936]) to test the validity and utility of LBA inferred from cross-sectional MRI data, i.e., a single MRI scan per participant. LBA was simply calculated based on the relationship between total brain volume (TBV) and intracranial volume (ICV), using three computationally distinct approaches: the difference ( ICV-TBV ), ratio ( TBV / ICV ), and regression-residual method (TBV∼ICV). LBA derived with all three methods were substantially correlated with well-validated neuroradiological atrophy rating scales ( r = 0.37-0.44). Compared with the difference or ratio method, LBA computed with the residual method most strongly captured phenotypic variance associated with cognitive decline ( r = 0.36), frailty ( r = 0.24), age-moderated brain shrinkage ( r = 0.45), and longitudinally-measured atrophic changes ( r = 0.36). LBA computed using a difference score was strongly correlated with baseline (i.e., ICV; r = 0.81) and yielded GWAS signal similar to ICV ( r g = 0.75). We performed the largest genetic study of LBA to date ( N = 43,110), which was highly heritable ( h 2 SNP GCTA = 41% [95% CI = 38-43%]) and had strong polygenic signal (LDSC h 2 = 26%; mean χ2 = 1.23). The strongest association in our genome-wide association study (GWAS) implicated WNT16 , a gene previously linked with neurodegenerative diseases such as Alzheimer, and Parkinson disease, and amyotrophic lateral sclerosis. This study is the first side-by-side evaluation of different computational approaches to estimate lifetime brain changes and their measurement characteristics. Careful assessment of methods for LBA computation had important implications for the interpretation of existing phenotypic and genetic results, and showed that relying on the residual method to estimate LBA from a single MRI scan captured brain shrinkage rather than current brain size. This makes this computationally-simple definition of LBA a strong candidate for more powerful analyses, promising accelerated genetic discoveries by maximising the use of available cross-sectional data.

Diagnostic value of the flare sign in predicting extracapsular extension in metastatic axillary lymph nodes and nodal status on breast magnetic resonance imaging.

This study aimed to evaluate the diagnostic performance of breast magnetic resonance imaging (MRI) in predicting extracapsular extension (ECE) and axillary nodal status in the axillary metastatic lymph nodes of patients with breast cancer. The preoperative MRI scans of 92 patients with breast cancer and axillary metastases who did not receive neoadjuvant treatment between January 2018 and January 2024 were retrospectively examined. The presence of an increased signal in the axillary fatty tissue surrounding the lymph node (flare sign) on T2-weighted images, irregular nodal contour (shaggy margin), axillary asymmetry (difference in the number and size of lymph nodes compared with the unaffected axilla), loss of the fatty hilum in the most suspicious lymph node, and morphological features on T1-weighted images were assessed. Each dissected axillary lymph node was examined for ECE, and the histopathological results were recorded. Axillary flare sign was significantly associated with the presence of ECE (P < 0.001), number of lymph nodes with ECE (P < 0.001), the presence of ≥4 axillary metastatic lymph nodes (P < 0.001), size of the primary tumor (P = 0.033), lymphovascular invasion in the primary tumor (P < 0.001), and presence of perineural invasion (P = 0.001). The flare sign exhibited 65.7% sensitivity, 96% specificity, 97.8% positive predictive value, 51.1% negative predictive value, and 73.9% accuracy in predicting ECE. Additionally, the receiver operating characteristic curve analysis revealed an area under the curve of 0.808 (95% confidence interval: 0.719-0.898). The flare sign has high performance in predicting ECE and axillary nodal status and is associated with primary tumor aggressiveness, indicating its potential utility in preoperative evaluation. The flare sign on breast MRI may play a crucial role in preoperative planning, surgical decision-making, and axillary status assessment by accurately predicting ECE.

Magnetic resonance imaging-guided single-fraction preoperative radiotherapy for early-stage breast cancer (the RICE trial): feasibility study

BackgroundOver the past decade, the adoption of screening programs, digital mammography, and magnetic resonance imaging (MRI) has increased early-stage breast cancer diagnosis rates. Mortality rates have decreased due to early detection and improved treatments, including personalized therapies. Accelerated partial-breast irradiation (APBI) is emerging as a convenient and effective treatment for some patients, with studies exploring its preoperative use. Preoperative APBI, especially with MRI guidance, offers improved tumor targeting and potentially reduced side effects. Magnetic Resonance Imaging-Guided Single-Fraction Pre-Operative Radiotherapy for Early-Stage Breast Cancer (RICE trial) aims to assess the feasibility and efficacy of MRI-guided single-dose radiotherapy (RT) for early-stage breast cancer.MethodsThe RICE study is a prospective, single-arm study evaluating single-fraction preoperative, APBI treatment for patients with early-stage breast cancer using a magnetic resonance imaging linear accelerator (MRI linac). Eligible patients enrolled in this study will have a core biopsy to confirm estrogen receptor-positive and HER2-negative sub-type. RT planning will use a planning computed tomography (CT) co-registered with a MRI with the patient in either the supine or prone position. For the diagnostic workup, [18F] fluorodeoxyglucose positron emission tomography/CT ([18F] FDG PET/CT) and [18F] fluoroestradiol positron emission tomography/CT ([18F] FES PET/CT) will be performed prior to treatment. Thirty patients will receive a single ablative RT dose of 21 Gray to the tumor. Pre-treatment and post-treatment MRI scans will be acquired at baseline and 5 weeks post-RT respectively. Breast-conserving surgery will be scheduled for 6 weeks after APBI treatment using the MRI linac.The primary study endpoint is the successful administration of a single fraction of preoperative breast RT under the guidance of an MRI linac. Secondary endpoints include evaluating the utility of MRI, [18F] FDG PET/CT, and [18F] FES PET/CT as a non-invasive method for assessing treatment response in patients undergoing single-fraction preoperative APBI.ConclusionThe RICE trial represents a significant step in breast cancer treatment, offering insights that could lead to treatment protocols with minimized RT appointments and enhanced patient outcomes.Trial registrationThis trial is registered with the Australian New Zealand Clinical Trials Registry (ANZCTR). Registered 31st of May 2021. Registration number: ACTRN12621000659808.

Subclinical imaging activity in multiple sclerosis patients during war-related psychological stress.

Psychological stress has been suggested as a contributory factor in the onset and progression of multiple sclerosis (MS). The 7 October 2023 terrorist attacks in Israel caused significant psychological stress, providing a unique context to study its impact on MS activity. This study aims to assess the impact of war-related psychological stress on MS activity using magnetic resonance imaging (MRI) scans and clinical follow-up. This observational retrospective case-control study includes 93 patients with MS (pwMS) who had routine annual MRI scans from three periods (7 October 2021 to 7 January 2022; 7 October 2022 to 7 January 2023; and 7 October 2023 to 7 January 2024). Data were collected from medical records and MRI scans at Hadassah Medical Center. MRI scans were classified as active if new or enlarging T2 lesions and/or enhancing T1 lesions were present. MRI activity significantly increased among pwMS during the first 3 months of the war compared to the corresponding period in the preceding year (11/93 vs. 23/93, P = 0.0139), with an OR of 4.0 (95% confidence interval: 1.29-16.442). pwMS with an EDSS score ≥4 showed a significant increase in MRI activity (P = 0.045), whereas no significant increase was observed in patients with an EDSS score ≤3.5 (P = 0.23). Additionally, MRI activity increased later during the war compared to the previous year (P < 0.0001). This study provides evidence of increased MRI-detected disease activity in pwMS during periods of war-related psychological stress. Our findings highlight the importance of considering psychological stress in MS management. Healthcare providers should be aware of the potential for increased disease activity in pwMS during extreme stress and may consider more frequent monitoring, including MRI scans, or treatment adjustments during such periods.

Added value of pre-procedural magnetic resonance angiography in transarterial embolization for refractory musculoskeletal pain.

Transarterial microembolization (TAME) is a minimally invasive treatment for chronic musculoskeletal disorders. Identifying angiogenesis and the supplying vessels of the target joint is important but challenging. Although magnetic resonance imaging (MRI) is commonly used to diagnose musculoskeletal diseases, it typically excludes vascular imaging. Dynamic contrast-enhanced magnetic resonance angiography (DCE-MRA) has the ability to visualize lesion angiogenesis, identify supplying vessels, and evaluate the vasculature anatomy. We propose that incorporating DCE-MRA into pre-procedural assessments can help identify the culprit vessels, arterial anatomy, and variant assessment of the target joint before TAME. We investigated six cases, each presenting pain in different body parts: shoulder adhesive capsulitis, trapezius myalgia, combined tennis and golf elbow, knee osteoarthritis, refractory knee pain after osteotomy, and plantar fasciitis. All patients underwent MRI with DCE-MRA before undergoing TAME. DCE-MRA was performed using either 1.5 T or 3 T MRI scanners, employing 3D-TRICKS or 4D-TRAK XD techniques. The numerical rating scale for pain was evaluated at one, three, and six months after the procedure, and any adverse events were recorded over the entire six-month follow-up period. Pre-procedural DCE-MRA helped to visualize angiogenesis at the lesion site in all patients and identify the supplying vessels, arterial vasculature anatomy, and branching variants. These findings corroborated the subsequent digital subtraction angiography (DSA) findings obtained during TAME. All patients experienced pain reduction and functional improvement after TAME without any complications. The average pain score reduced significantly after TAME treatment (p < 0.05). Two patients underwent a second MRI and DCE-MRA at the six-month follow-up and showed a significant reduction in angiogenesis. DCE-MRA offers a valuable pre-procedural assessment tool for TAME procedures by facilitating the visualization of angiogenesis at the lesion site, supplying vessels, and arterial anatomic variants, including the variable orifice of the supplying branches. This information can potentially improve patient selection and pre-procedural planning, leading to better outcomes and reduced risk of complications.

Repeatability of quantitative MR fingerprinting for T1 and T2 measurements of metastatic bone in prostate cancer patients.

MR fingerprinting (MRF) has the potential to quantify treatment response. This study evaluated the repeatability of MRF-derived T1 and T2 relaxation times in bone metastasis, bone, and muscle in patients with metastatic prostate cancer. This prospective single-centre study included same-day repeated MRF acquisitions from 20 patients (August 2019-October 2020). Phantom and human data were acquired on a 1.5-T MR scanner using a research MRF sequence outputting T1 and T2 maps. Regions of interest (ROIs) across three tissue types (bone metastasis, bone, muscle) were drawn on two separate acquisitions. Repeatability of T1 and T2 was assessed using Bland-Altman plots, together with repeatability (r) and intraclass correlation (ICC) coefficients. Mean T1 and T2 were reported per tissue type. Twenty patients with metastatic prostate cancer (mean age, 70 years ± 8 (standard deviation)) were evaluated and bone metastasis (n = 44), normal-appearing bone (n = 14), and muscle (n = 20) ROIs were delineated. Relative repeatability of T1 measurements was 6.9% (bone metastasis), 32.6% (bone), 5.8% (muscle) and 21.8%, 32.2%, 16.1% for T2 measurements. The ICC of T1 was 0.97 (bone metastasis), 0.94 (bone), 0.96 (muscle); ICC of T2 was 0.94 (bone metastasis), 0.94 (bone), 0.91 (muscle). T1 values in bone metastasis were higher than in bone (p < 0.001). T2 values showed no difference between bone metastasis and bone (p = 0.5), but could separate active versus treated metastasis (p < 0.001). MRF allows repeatable T1 and T2 measurements in bone metastasis, bone, and muscle in patients with primary prostate cancer. Such measurements may help quantify the treatment response of bone metastasis. Question MR fingerprinting has the potential to characterise bone metastasis and its response to treatment. Findings Repeatability of MRF-based T1 measurements in bone metastasis and muscle was better than for T2. Clinical relevance MR fingerprinting allows repeatable T1 and T2 quantitative measurements in bone metastasis, bone, and muscle in patients with primary prostate cancer, which makes it potentially applicable for disease characterisation and assessment of treatment response.

Unbiased and reproducible liver MRI-PDFF estimation using a scan protocol-informed deep learning method.

To estimate proton density fat fraction (PDFF) from chemical shift encoded (CSE) MR images using a deep learning (DL)-based method that is precise and robust to different MR scanners and acquisition echo times (TEs). Variable echo times neural network (VET-Net) is a two-stage framework that first estimates nonlinear variables of the CSE-MR signal model, to posteriorly estimate water/fat signal components using the least-squares method. VET-Net incorporates a vector with TEs as an auxiliary input, therefore enabling PDFF calculation with any TE setting. A single-site liver CSE-MRI dataset (188 subjects, 4146 axial slices) was considered, which was split into training (150 subjects), validation (18), and testing (20) subsets. Testing subjects were scanned using several protocols with different TEs, which we then used to measure the PDFF reproducibility coefficient (RDC) at two regions of interest (ROIs): the right posterior and left hepatic lobes. An open-source multi-site and multi-vendor fat-water phantom dataset was also used for PDFF bias assessment. VET-Net showed RDCs of 1.71% and 1.04% on the right posterior and left hepatic lobes, respectively, across different TEs, which was comparable to a reference graph cuts-based method (RDCs = 1.71% and 0.86%). VET-Net also showed a smaller PDFF bias (-0.55%) than graph cuts (0.93%) when tested on a multi-site phantom dataset. Reproducibility (1.94% and 1.59%) and bias (-2.04%) were negatively affected when the auxiliary TE input was not considered. VET-Net provided unbiased and precise PDFF estimations using CSE-MR images from different hardware vendors and different TEs, outperforming conventional DL approaches. Question Reproducibility of liver PDFF DL-based approaches on different scan protocols or manufacturers is not validated. Findings VET-Net showed a PDFF bias of -0.55% on a multi-site phantom dataset, and RDCs of 1.71% and 1.04% at two liver ROIs. Clinical relevance VET-Net provides efficient, in terms of scan and processing times, and unbiased PDFF estimations across different MR scanners and scan protocols, and therefore it can be leveraged to expand the use of MRI-based liver fat quantification to assess hepatic steatosis.

Lower DTI-ALPS index in patients with major depressive disorder: Correlation with fatigue

Background and purposeDiffusion tensor imaging along perivascular spaces (DTI-ALPS) is an index that may provide insights into intracranial waste clearance processes. Glymphatic system dysfunction has been suggested to play a role in the development of major depressive disorder (MDD). Additionally, fatigue—a common precursor of MDD—is also closely connected to the waste clearance function of the central nervous system (CNS), further underscoring the significance of efficient waste removal in MDD. However, evidence linking altered DTI-ALPS index to MDD remains limited. This study aims to investigate the changes in the DTI-ALPS index in patients with MDD and explore the potential interplay between DTI-ALPS index alterations, fatigue, and the presence of MDD. Material and methodsA total of 46 patients with MDD and 55 healthy controls (HC) were included in the study. All participants underwent diffusion tensor imaging using the same 3-T MRI (3-Tesla Magnetic Resonance Imaging) scanner. The DTI-ALPS index was assessed, and the Chalder Fatigue Scale (CFS) was used to evaluate fatigue levels in both groups, and the 17-item Hamilton Depression Rating Scale (HAMD-17) was used to evaluate the severity of depression in the patients. We compared the DTI-ALPS index and clinical characteristics between the MDD and HC group, and explored the relationship among the DTI-ALPS index, CFS scores, and the presence of MDD through mediation analysis. ResultsThe DTI-ALPS index in the right hemisphere (DTI-ALPS-R) is significantly lower in patients with MDD (t = 2.41, P = 0.02). The MDD patients exhibited significantly higher scores on the CFS scales compared with HCs (t = 13.12, P <.001). Mediation analysis showed that the CFS score plays a significant mediating role between DTI-ALPS-R and the presence of MDD, acting as a full mediator (indirect effect β = −0.230, 95 % CI: [-0.388, −0.059]). ConclusionOur study found that patients with MDD have a reduced DTI-ALPS index. This reduction appears to contribute to the development of MDD by facilitating the accumulation of fatigue symptoms. These findings may provide a new perspective on the pathogenesis of MDD, suggest a potential new biomarker for MDD, and offer new insights for its treatment.

The influence of alterations in the composition of intestinal microbiota on neurovascular coupling and cognitive dysfunction in individuals afflicted with CSVD

IntroductionAn expanding body of research has explored the crucial role of gut microbiota in cerebral small vessel disease (CSVD). The objective of this study is to investigate alterations in the gut microbiota structure among CSVD patients, to explore the correlation between differential taxonomic levels and the neurovascular coupling index as well as cognitive function and to elucidate the imaging and biomarkers of mild cognitive impairment (MCI) in CSVD. MethodsWe enrolled 104 patients with CSVD and 40 healthy controls (HC). Based on cognitive test scores, CSVD patients were categorized into a cognitively normal group (CSVD-NCI, n=61) and a mild cognitive impairment group (CSVD-MCI, n=43). Performing magnetic resonance imaging (MRI) scans, gut microbiota analysis, as well as clinical and neuropsychological assessments for all participants. Based on arterial spin labeling (ASL) and blood oxygen level-dependent (BOLD) imaging data, cerebral blood flow (CBF) and neural activity indices are computed. The coupling indices of CBF/mReHo, CBF/mfALFF, CBF/mALFF, and CBF/mDC are calculated to assess the whole-brain neurovascular coupling changes in patients with CSVD. ResultsSpecies annotation revealed differences in the composition at the phylum and genus levels among the HC, CSVD-NCI, and CSVD-MCI groups. Additionally, differential analysis using the Kruskal-Wallis test demonstrated specific dominant microbial communities in all three groups. The relative abundance of certain dominant microbial communities in CSVD patients exhibited correlations with neurovascular coupling and cognitive function. The combined assessment of Bacteroides genus and CBF/mDC proved effective in distinguishing between CSVD-NCI and CSVD-MCI, providing a novel non-invasive approach for the diagnosis of MCI in CSVD.

Inverse Association between the Body Mass Index and the Incidence of Unruptured Intracranial Aneurysms-Insights from the Hamburg City Health Population Study.

Overweight/obese patients experience a lower incidence of subarachnoid hemorrhage (SAH) compared to non-overweight patients, even though elevated body mass index (BMI) has been associated with various SAH risk factors. Given that intracranial aneurysms are a primary cause of SAH, a potential protective effect of a high BMI on intracranial aneurysms is likely but remains insufficiently investigated. This population-based MRI study aims to conduct detailed analyses on risk factors associated with the incidence of unruptured intracranial aneurysms (UIA). Retrospective analysis of subjects enrolled in the prospective Hamburg City Health study who underwent intracranial magnetic resonance imaging (MRI) was done. MRI scans were screened for UIA using time-of-flight angiography. Subject data including medical history, laboratory examinations, and risk factors for UIA were collected, and a multivariable logistic regression model was used to investigate the relationship between risk factors and UIA incidence. 2688 subjects (mean (IQR) age, 65 (58-71); 1176 female (43.8%) were included. An UIA was detected in 214 subjects with an incidence of 10.6% (6.0%) in females (males). Determinants for UIA were female sex (OR 2.00, 95%CI 1.45-2.77, p < 0.001), hypertension (OR 1.48, 95%CI 1.08-2.04, p = 0.015), smoking (OR 1.41, 95%CI 1.03-1.95, p = 0.036), and BMI (OR 0.95, 95%CI 0.91-0.98, p = 0.004). Among subjects with UIA, 9.4% with a BMI > 25 had multiple aneurysms, compared to 21.6% with BMI ≤ 25 (p = 0.012). This study suggests that a high BMI exhibits a protective effect on UIA incidence and the development of multiple aneurysms. Additionally, the data confirms established risk factors for UIA development, such as female sex, hypertension, and smoking.

Natural Course of the Maxillary Sinus Fungus Ball: Results From Seoul National University Hospital Healthcare Center.

The frequency of paranasal sinus fungus balls, a common form of rhinosinusitis, has increased. Although treatment and causative factors have been well investigated, the evolving nature of the fungal balls remains unelucidated. This study aimed to investigate and analyze the changing patterns of fungus balls. This retrospective study analyzed data from 35 participants selected from a pool of 41,497 patients who underwent brain magnetic resonance imaging (MRI) at a large health care center. The extent of the fungus balls was evaluated by grading them from 1 to 4 based on the MR images. The changing process of the fungus ball was analyzed based on demographics, interval between the MRI scans, comorbidities, and specific dental interventions. The fungus ball grades showed significant progression over time. In the analysis of 29 sinuses with initially low-grade (grades 0, 1, and 2) fungus balls, 15 sinuses showed a grade change <2 (no/minimal change group), whereas 14 sinuses showed grade changes of ≥2 (substantial change group). Intergroup comparison showed that only the interval between the initial and final MRI scans differed significantly (p = 0.008). However, factors, such as age, sex, comorbidities, and history of dental procedures, did not differ significantly between the two groups. This study shows the extent of change in fungus balls, primarily over time. These results offer critical insights into the natural course and progression of the maxillary sinus fungus ball. 4 Laryngoscope, 2024.

Hydronium-Crosslinked Inorganic Hydrogel Comprised of 1D Lepidocrocite Titanate Nanofilaments.

When a few drops of acid (hydrochloric, acrylic, propionic, acetic, or formic) are added to a colloid comprised of 1D lepidocrocite titanate nanofilaments (1DLs)-2 × 2 TiO6 octahedra in cross-section-a hydrogel forms, in many cases, within seconds. The 1DL synthesis process requires the reaction between titanium diboride with tetramethylammonium (TMA+), hydroxide. Using quantitative nuclear magnetic resonance (qNMR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC), the mass percent of TMA+ after synthesis is determined to be ≈ 13.1±0.1%. The TMA+ is completely removed from the gels after 2 water soak cycles, resulting in the first completely inorganic, TiO2-based hydrogels. Ion exchanging the TMA+ with hydronium results in gels with relatively strong hydrogen bonds. The hydrogels' compression strengths increased linearly with 1DL colloid concentration. At a 1DL concentration of 45gL-1, the compressive strength, at 80% deformation when acrylic acid is used, is ≈325kPa. The strengths are ≈ 50% greater after the TMA+ is removed. The removal of all residual organic components in the hydrogels, including TMA+, is confirmed by qNMR, Fourier-transformed infrared spectroscopy (FTIR), and TGA/DSC. The 1DL phase is retained after gelation, TMA+ removal, and 80% compression.