Anatomical Magnetic Resonance Imaging Research Articles

Normal cardiac dimensions by magnetic resonance imaging and topographic anatomy of the adult arabian one-humped camel (Camelus dromedarius)

BackgroundDromedaries’ normal heart architecture and size have not been adequately examined utilizing magnetic resonance imaging (MRI) and topographic anatomy.Resultwe aimed to investigate the regular appearance of the heart and its dimensions, using MRI and cross-sectional anatomy, in mature Arabian one-humped camels (Camelus dromedarius). We also analyzed hematological and cardiac biochemical markers. MRI scans were conducted on twelve camel heart cadavers using a closed 1.5-Tesla magnet with fast spin echo (FSE) weighted sequences. Subsequently, the hearts were cross-sectionally sliced. Additionally, hematobiochemical studies were conducted on ten mature live camels. The study analyzed standard cardiac dimensions including HL, BW, RA, LA, RV, LV, IVS, LAD, RAD, RVD, AoD, TCVD, and MVD. The results showed a strong positive correlation between the cardiac dimensions obtained from both gross analysis and MR images, with no significant difference between them. On both gross and MRI images, the usual structures of the heart were identified and labeled. Along with the cardiac markers (creatine kinase and troponin), the average hematological values and standard biochemical parameters were also described.ConclusionAccording to what we know, this investigation demonstrates, for the first time the typical heart structures and dimensions of the heart in dromedaries, and it could serve as a basis for diagnosing cardiac disorders in these animals.

Few sex differences in regional gray matter volume growth trajectories across early childhood

Abstract Sex-specific developmental differences in brain structure have been documented in older children and adolescents, with females generally showing smaller overall brain volumes and earlier peak ages than males. However, sex differences in gray matter structural development in early childhood are less studied. We characterized sex-specific trajectories of gray matter volume development in children aged 2–8 years. We acquired anatomical magnetic resonance imaging (MRI) of the brain at the Alberta Children's Hospital in 123 typically developing children. Most children were scanned multiple times, for a total of 393 scans (mean = 3.2 scans/subject). We segmented T1-weighted structural MRI with MaCRUISE to define 116 regions and measured both absolute volumes (mm3) and proportional volumes (percent of intracranial volume). We characterized growth trajectories of gray matter volume for these brain regions between 2 and 8 years using mixed-effects models, showing volume increases, with most posterior and temporo-parietal regions peaking before 8 years. We found widespread main effects of sex, with males having larger volumes in 86% of brain regions. However, there were no significant sex differences in trajectories (age or age2 terms) for absolute volume. Proportional volumes of the right occipital fusiform gyrus and left medial postcentral gyrus showed significant age-by-sex interactions where females had steeper volume decreases than males. This study also confirms regional patterns observed in previous studies of older children, such as posterior-to-anterior timing of brain maturation. These results provide a comprehensive picture of gray matter volume development across early childhood, and suggest that sex differences do not emerge until later in development.

Demystifying the "Dark Side of the Knee": An Update on Imaging of the Posterolateral Corner.

The posterolateral corner (PLC) of the knee is a complex anatomical-functional unit that includes ligamentous and tendinous structures that are crucial for joint stability. This review discusses the intricate anatomy, biomechanics, and imaging modalities, as well as the current challenges in diagnosing PLC injuries, with an emphasis on magnetic resonance imaging (MRI). Recognizing the normal MRI anatomy is critical in identifying abnormalities and guiding effective treatment strategies. Identification of the smaller structures of the PLC, traditionally difficult to depict on imaging, may not be necessary to diagnose a clinically significant PLC injury. Injuries to the PLC, often associated with cruciate ligament tears, should be promptly identified because failure to recognize them may result in persistent instability, secondary osteoarthritis, and cruciate graft failure.

New insights into the effects of type and timing of childhood maltreatment on brain morphometry.

Childhood maltreatment (CM) is known to influence brain development. To obtain a better understanding of related brain alterations, recent research has focused on the influence of the type and timing of CM. We aimed to investigate the association between type and timing of CM and local brain volume. Anatomical magnetic resonance images were collected from 93 participants (79 female/14 male) with a history of CM. CM history was assessed with the German Interview Version of the "Maltreatment and Abuse Chronology of Exposure" scale, "KERF-40 + ". Random forest regressions were performed to assess the impact of CM characteristics on the volume of amygdala, hippocampus and anterior cingulate cortex (ACC). The volume of the left ACC was predicted by neglect at age 3 and 4 and abuse at age 16 in a model including both type and timing of CM. For the right ACC, overall CM severity and duration had the greatest impact on volumetric alterations. Our data point to an influence of CM timing on left ACC volume, which was most pronounced in early childhood and in adolescence. We were not able to replicate previously reported effects of maltreatment type and timing on amygdala and hippocampal volume.

Origin coordinate influence on performance of temporally extended signal space separation in magnetoencephalography

ObjectiveTemporally extended signal space separation (tSSS) is a powerful method for artifact suppression in magnetoencephalography (MEG). Because tSSS first separates MEG signals coming from inside and outside a certain sphere, definition of the sphere origin is important. For this study, we explored the influence of origin choice on tSSS performance in spontaneous and evoked activity from epilepsy patients. MethodsInterictal epileptiform discharges (IEDs) and somatosensory evoked fields (SEFs) were processed with two tSSSs: one with the default origin of (0, 0, 40 mm) in the head coordinate, and the other with an individual origin estimated using each patient’s anatomical magnetic resonance imaging (MRI). Equivalent current dipoles (ECDs) were calculated for the data. The ECD location and quality of estimation were compared across conditions. ResultsMEG data from 21 patients revealed marginal differences in ECD location, but the estimation quality inferred from goodness of fit (GOF) and confidence volume (CV) was better for the tSSS with individual origins. This choice affected IEDs more than it affected SEFs. ConclusionsIndividual sphere model resulted in better GOF and CV. SignificanceApplication of tSSS using an individual origin would be more desirable when available. This parameter might influence spontaneous activity more strongly.

In vivo neuropil density from anatomical MRI and machine learning.

Brain energy budgets specify metabolic costs emerging from underlying mechanisms of cellular and synaptic activities. While current bottom-up energy budgets use prototypical values of cellular density and synaptic density, predicting metabolism from a person's individualized neuropil density would be ideal. We hypothesize that in vivo neuropil density can be derived from magnetic resonance imaging (MRI) data, consisting of longitudinal relaxation (T1) MRI for gray/white matter distinction and diffusion MRI for tissue cellularity (apparent diffusion coefficient, ADC) and axon directionality (fractional anisotropy, FA). We present a machine learning algorithm that predicts neuropil density from in vivo MRI scans, where ex vivo Merker staining and in vivo synaptic vesicle glycoprotein 2A Positron Emission Tomography (SV2A-PET) images were reference standards for cellular and synaptic density, respectively. We used Gaussian-smoothed T1/ADC/FA data from 10 healthy subjects to train an artificial neural network, subsequently used to predict cellular and synaptic density for 54 test subjects. While excellent histogram overlaps were observed both for synaptic density (0.93) and cellular density (0.85) maps across all subjects, the lower spatial correlations both for synaptic density (0.89) and cellular density (0.58) maps are suggestive of individualized predictions. This proof-of-concept artificial neural network may pave the way for individualized energy atlas prediction, enabling microscopic interpretations of functional neuroimaging data.

Characterization of tau propagation pattern and cascading hypometabolism from functional connectivity in Alzheimer's disease.

Tau pathology and its spatial propagation in Alzheimer's disease (AD) play crucial roles in the neurodegenerative cascade leading to dementia. However, the underlying mechanisms linking tau spreading to glucose metabolism remain elusive. To address this, we aimed to examine the association between pathologic tau aggregation, functional connectivity, and cascading glucose metabolism and further explore the underlying interplay mechanisms. In this prospective cohort study, we enrolled 79 participants with 18F-Florzolotau positron emission tomography (PET), 18F-fluorodeoxyglucose PET, resting-state functional, and anatomicalmagnetic resonance imaging (MRI) images in the hospital-based Shanghai Memory Study. We employed generalized linear regression and correlation analyses to assess the associations between Florzolotau accumulation, functional connectivity, and glucose metabolism in whole-brain and network-specific manners. Causal mediation analysis was used to evaluate whether functional connectivity mediates the association between pathologic tau and cascading glucose metabolism. We examined 22 normal controls and 57 patients with AD. In the AD group, functional connectivity was associated with Florzolotau covariance (β = .837, r = 0.472, p < .001) and glucose covariance (β = 1.01, r = 0.499, p < .001). Brain regions with higher tau accumulation tend to be connected to other regions with high tau accumulation through functional connectivity or metabolic connectivity. Mediation analyses further suggest that functional connectivity partially modulates the influence of tau accumulation on downstream glucose metabolism (mediation proportion: 49.9%). Pathologic tau may affect functionally connected neurons directly, triggering downstream glucose metabolism changes. This study sheds light on the intricate relationship between tau pathology, functional connectivity, and downstream glucose metabolism, providing critical insights into AD pathophysiology and potential therapeutic targets.

Возможности магнитно-резонансной томографии в диагностике воспалительных изменений парауретральных желез у женщин.

Introduction. Inflammation of the paraurethral glands (skеneitis) is a complex urological disease, often hidden under the guise of other pathological conditions and causing recurrent lower urinary tract infection (UTI) in women. A significant problem for the diagnosis of skineitis at present is the absence or extremely low sensitivity and specificity of available laboratory, instrumental and radiation methods. Thus, the search for new ways to examine patients with recurrent UTI caused by chronic inflammation of the Skene’s glands is an important clinical and socio-economic task of modern healthcare. Materials and methods. The study involved 30 patients aged from 24 to 51 years who underwent magnetic resonance imaging (MRI) of the pelvis with contrast enhancement and targeted examination of the urethra and periurethral area using a device with a 3T fi ld strength. To study the MR semiotics of chronic inflammation of the gallbladder, in addition to standard MR protocols, high-resolution T2-weighted images with a slice thickness of 2 mm and T2-weighted Space 3D images in a sagittal projection with a slice thickness of 1 mm were used. The first group consisted of 16 urologically healthy women without complaints of dysuria, who underwent an assessment of the MRI anatomy of the normal female urethra. MRI of 14 respondents with chronic infl mmation of the paraurethral glands (second group) was performed to search for recurring (natural) changes characteristic of this disease. Such parameters as the diameter of the urethra, the separate thickness of its anterior and posterior walls, clarity at the boundary of the layers, and the presence of pathological changes and formations were studied. Results. Analysis of the obtained tomograms showed that urologically healthy respondents are characterized by symmetrical thickness of the walls of the urethra without pathological formations in it, as well as evenness and clarity of the contour at the boundary of the layers. When studying the results of examination of patients with chronic skeneitis, all of them (100%) noted the following recurring changes: an increase in the diameter of the urethra due to thickening of its posterior wall, in particular the submucosal layer, impaired differentiation at the border of the submucosal and muscular layers, the presence of small cystic changes in the structure of the posterior wall of the urethra (85.7%) or fragmentarily dilated ducts of the urinary tract (14%). Hypertrophy of the bulbospongiosus muscles, detected in 85.7% of respondents in the second group, is likely an indicator of frequent exacerbations and duration of the disease, and can be considered as an additional nonspecific criterion for this disease. Conclusions. These changes can tentatively, given the small sample, be considered pathognomonic MR signs of chronic skineitis. Thus, MRI of the pelvis with a targeted examination of the urethra and periurethral area can help in the differential diagnosis of patients with suspected inflammation of the paraurethral glands, establishing the correct diagnosis and prescribing adequate treatment.

Anal and Perianal Masses: The Common, the Uncommon, and the Rare

AbstractA variety of tumors involve the anal canal because the anal canal forms the transition between the digestive system and the skin, and this anatomical region is made of a variety of different cells and tissues. Magnetic resonance imaging (MRI) is the modality of choice for diagnosis and local staging of the anal canal and perianal neoplasms. In this pictorial review, we demonstrate the MRI anatomy of the anal canal and perianal region and display the imaging spectrum of tumors in the region along with an overview of its management. Imaging appearances of many tumorlike lesions that can cause diagnostic dilemmas are also demonstrated with pointers to differentiate between them.

Challenges, limitations, and pitfalls of PET and advanced MRI in patients with brain tumors: A report of the PET/RANO group.

Brain tumor diagnostics have significantly evolved with the use of positron emission tomography (PET) and advanced magnetic resonance imaging (MRI) techniques. In addition to anatomical MRI, these modalities may provide valuable information for several clinical applications such as differential diagnosis, delineation of tumor extent, prognostication, differentiation between tumor relapse and treatment-related changes, and the evaluation of response to anticancer therapy. In particular, joint recommendations of the Response Assessment in Neuro-Oncology (RANO) Group, the European Association of Neuro-oncology, and major European and American Nuclear Medicine societies highlighted that the additional clinical value of radiolabeled amino acids compared to anatomical MRI alone is outstanding and that its widespread clinical use should be supported. For advanced MRI and its steadily increasing use in clinical practice, the Standardization Subcommittee of the Jumpstarting Brain Tumor Drug Development Coalition provided more recently an updated acquisition protocol for the widely used dynamic susceptibility contrast perfusion MRI. Besides amino acid PET and perfusion MRI, other PET tracers and advanced MRI techniques (e.g. MR spectroscopy) are of considerable clinical interest and are increasingly integrated into everyday clinical practice. Nevertheless, these modalities have shortcomings which should be considered in clinical routine. This comprehensive review provides an overview of potential challenges, limitations, and pitfalls associated with PET imaging and advanced MRI techniques in patients with gliomas or brain metastases. Despite these issues, PET imaging and advanced MRI techniques continue to play an indispensable role in brain tumor management. Acknowledging and mitigating these challenges through interdisciplinary collaboration, standardized protocols, and continuous innovation will further enhance the utility of these modalities in guiding optimal patient care.

Deep learning segmentation of the choroid plexus from structural magnetic resonance imaging (MRI): validation and normative ranges across the adult lifespan

BackgroundThe choroid plexus functions as the blood-cerebrospinal fluid (CSF) barrier, plays an important role in CSF production and circulation, and has gained increased attention in light of the recent elucidation of CSF circulation dysfunction in neurodegenerative conditions. However, methods for routinely quantifying choroid plexus volume are suboptimal and require technical improvements and validation. Here, we propose three deep learning models that can segment the choroid plexus from commonly-acquired anatomical MRI data and report performance metrics and changes across the adult lifespan.MethodsFully convolutional neural networks were trained from 3D T1-weighted, 3D T2-weighted, and 2D T2-weighted FLAIR MRI using gold-standard manual segmentations in control and neurodegenerative participants across the lifespan (n = 50; age = 21–85 years). Dice coefficients, 95% Hausdorff distances, and area-under-curve (AUCs) were calculated for each model and compared to segmentations from FreeSurfer using two-tailed Wilcoxon tests (significance criteria: p < 0.05 after false discovery rate multiple comparisons correction). Metrics were regressed against lateral ventricular volume using generalized linear models to assess model performance for varying levels of atrophy. Finally, models were applied to an expanded cohort of adult controls (n = 98; age = 21–89 years) to provide an exemplar of choroid plexus volumetry values across the lifespan.ResultsDeep learning results yielded Dice coefficient = 0.72, Hausdorff distance = 1.97 mm, AUC = 0.87 for T1-weighted MRI, Dice coefficient = 0.72, Hausdorff distance = 2.22 mm, AUC = 0.87 for T2-weighted MRI, and Dice coefficient = 0.74, Hausdorff distance = 1.69 mm, AUC = 0.87 for T2-weighted FLAIR MRI; values did not differ significantly between MRI sequences and were statistically improved compared to current commercially-available algorithms (p < 0.001). The intraclass coefficients were 0.95, 0.95, and 0.96 between T1-weighted and T2-weighted FLAIR, T1-weighted and T2-weighted, and T2-weighted and T2-weighted FLAIR models, respectively. Mean lateral ventricle choroid plexus volume across all participants was 3.20 ± 1.4 cm3; a significant, positive relationship (R2 = 0.54-0.60) was observed between participant age and choroid plexus volume for all MRI sequences (p < 0.001).ConclusionsFindings support comparable performance in choroid plexus delineation between standard, clinically available, non-contrasted anatomical MRI sequences. The software embedding the evaluated models is freely available online and should provide a useful tool for the growing number of studies that desire to quantitatively evaluate choroid plexus structure and function (https://github.com/hettk/chp_seg).

Distributed source modeling of stereoencephalographic measurements of ictal activity

ObjectivesStereoelectroencephalography (SEEG) can define the epileptogenic zone (EZ). However, SEEG is susceptible to the sampling bias, where no SEEG recording is taken within a circumscribed EZ. MethodsNine patients with medically refractory epilepsy underwent SEEG recording, and brain resection got positive outcomes. Ictal neuronal currents were estimated by distributed source modeling using the SEEG data and individual’s anatomical magnetic resonance imaging. Using a retrospective leave-one-out data sub-sampling, we evaluated the sensitivity and specificity of the current estimates using MRI after surgical resection or radio-frequency ablation. ResultsThe sensitivity and specificity in detecting the EZ were indistinguishable from either the data from all electrodes or the sub-sampled data (rank sum test: rank sum = 23719, p = 0.13) when at least one remaining electrode contact was no more than 20 mm away. ConclusionsThe distributed neuronal current estimates of ictal SEEG data can mitigate the challenge of delineating the boundary of the EZ in cases of missing an electrode implanted within the EZ and a required second SEEG exploration. SignificanceDistributed source modeling can be a tool for clinicians to infer the EZ by allowing for more flexible planning of the electrode implantation route and minimizing the number of electrodes.

Personalized depth-specific neuromodulation of the human primary motor cortex via ultrasound.

Non-invasive brain stimulation has the potential to boost neuronal plasticity in the primary motor cortex (M1), but it remains unclear whether the stimulation of both superficial and deep layers of the human motor cortex can effectively promote M1 plasticity. Here, we leveraged transcranial ultrasound stimulation (TUS) to precisely target M1 circuits at depths of approximately 5mm and 16mm from the cortical surface. Initially, we generated computed tomography images from each participant's individual anatomical magnetic resonance images (MRI), which allowed for the generation of accurate acoustic simulations. This process ensured that personalized TUS was administered exactly to the targeted depths within M1 for each participant. Using long-term depression and long-term potentiation (LTD/LTP) theta-burst stimulation paradigms, we examined whether TUS over distinct depths of M1 could induce LTD/LTP plasticity. Our findings indicated that continuous theta-burst TUS-induced LTD-like plasticity with both superficial and deep M1 stimulation, persisting for at least 30min. In comparison, sham TUS did not significantly alter M1 excitability. Moreover, intermittent theta-burst TUS did not result in the induction of LTP- or LTD-like plasticity with either superficial or deep M1 stimulation. These findings suggest that the induction of M1 plasticity can be achieved with ultrasound stimulation targeting distinct depths of M1, which is contingent on the characteristics of TUS. KEY POINTS: The study integrated personalized transcranial ultrasound stimulation (TUS) with electrophysiology to determine whether TUS targeting superficial and deep layers of the human motor cortex (M1) could elicit long-term depression (LTD) or long-term potentiation (LTP) plastic changes. Utilizing acoustic simulations derived from individualized pseudo-computed tomography scans, we ensured the precision of TUS delivery to the intended M1 depths for each participant. Continuous theta-burst TUS targeting both the superficial and deep layers of M1 resulted in the emergence of LTD-like plasticity, lasting for at least 30min. Administering intermittent theta-burst TUS to both the superficial and deep layers of M1 did not lead to the induction of LTP- or LTD-like plastic changes. We suggest that theta-burst TUS targeting distinct depths of M1 can induce plasticity, but this effect is dependent on specific TUS parameters.

Trauma-related intrusive memories and anterior hippocampus structural covariance: an ecological momentary assessment study in posttraumatic stress disorder

Trauma-related intrusive memories (TR-IMs) are hallmark symptoms of posttraumatic stress disorder (PTSD), but their neural correlates remain partly unknown. Given its role in autobiographical memory, the hippocampus may play a critical role in TR-IM neurophysiology. The anterior and posterior hippocampi are known to have partially distinct functions, including during retrieval of autobiographical memories. This study aimed to investigate the relationship between TR-IM frequency and the anterior and posterior hippocampi morphology in PTSD. Ninety-three trauma-exposed adults completed daily ecological momentary assessments for fourteen days to capture their TR-IM frequency. Participants then underwent anatomical magnetic resonance imaging to obtain measures of anterior and posterior hippocampal volumes. Partial least squares analysis was applied to identify a structural covariance network that differentiated the anterior and posterior hippocampi. Poisson regression models examined the relationship of TR-IM frequency with anterior and posterior hippocampal volumes and the resulting structural covariance network. Results revealed no significant relationship of TR-IM frequency with hippocampal volumes. However, TR-IM frequency was significantly negatively correlated with the expression of a structural covariance pattern specifically associated with the anterior hippocampus volume. This association remained significant after accounting for the severity of PTSD symptoms other than intrusion symptoms. The network included the bilateral inferior temporal gyri, superior frontal gyri, precuneus, and fusiform gyri. These novel findings indicate that higher TR-IM frequency in individuals with PTSD is associated with lower structural covariance between the anterior hippocampus and other brain regions involved in autobiographical memory, shedding light on the neural correlates underlying this core symptom of PTSD.

Preserved Gray Matter Volume in the Left Superior Temporal Gyrus Underpins Speech-in-Noise Processing in Middle-Aged Adults.

Neuroanatomical evidence suggests that behavioral speech-in-noise (SiN) perception and the underlying cortical structural network are altered by aging, and these aging-induced changes could be initiated during middle age. However, the mechanism behind the relationship between auditory performance and neural substrates of speech perception in middle-aged individuals remains unclear. In this study, we measured the structural volumes of selected neuroanatomical regions involved in speech and hearing processing to establish their association with speech perception ability in middle-aged adults. Sentence perception in quiet and noisy conditions was behaviorally measured in 2 different age groups: young (20-39 years old) and middle-aged (40-59-year-old) adults. Anatomical magnetic resonance images were taken to assess the gray matter volume of specific parcellated brain areas associated with speech perception. The relationships between these and behavioral auditory performance with age were determined. The middle-aged adults showed poorer speech perception in both quiet and noisy conditions than the young adults. Neuroanatomical data revealed that the normalized gray matter volume in the left superior temporal gyrus, which is closely related to acoustic and phonological processing, is associated with behavioral SiN perception in the middle-aged group. In addition, the normalized gray matter volumes in multiple cortical areas seem to decrease with age. The results indicate that SiN perception in middle-aged adults is closely related to the brain region responsible for lower-level speech processing, which involves the detection and phonemic representation of speech. Nonetheless, the higher-order cortex may also contribute to age-induced changes in auditory performance.

Predicting intraoperative hemorrhage during curettage treatment of cesarean scar pregnancy using free-breathing GRASP DCE-MRI

ObjectiveTo explore the feasibility of the golden-angle radial sparse parallel (GRASP) dynamic magnetic resonance imaging (MRI) technique in predicting the intraoperative bleeding risk of scar pregnancy.MethodsA total of 49 patients with cesarean scar pregnancy (CSP) who underwent curettage and GRASP-MRI imaging were retrospectively selected between January 2021 and July 2022. The pharmacokinetic parameters, including Wash-in, Wash-out, time to peck (TTP), initial area under the curve (iAUC), the transfer rate constant (Ktrans), constant flow rate (Kep), and volume of extracellular space (Ve), were calculated. The amount of intraoperative bleeding was recorded by a gynecologist who performed surgery, after which patients were divided into non-hemorrhage (blood loss ≤ 200 mL) and hemorrhage (blood loss > 200 mL) groups. The measured pharmacokinetic parameters were statistically compared using the t-test or Mann–Whitney U test with a significant level set to be p < 0.05. The receiver operating characteristic (ROC) curve was constructed, and the area under the curve (AUC) was calculated to evaluate each parameter’s capability in intraoperative hemorrhage subgroup classification.ResultsTwenty patients had intraoperative hemorrhage (blood loss > 200 mL) during curettage. The hemorrhage group had larger Wash-in, iAUC, Ktrans, Ve, and shorter TTP than the non-hemorrhage group (all P > 0.05). Wash-in had the highest AUC value (0.90), while Ktrans had the lowest value (0.67). Wash-out and Kep were not significantly different between the two groups.ConclusionGRASP DCE-MRI has the potential to forecast intraoperative hemorrhage during curettage treatment of CSP, with Wash-in exhibiting the highest predictive performance. This data holds promise for advancing personalized treatment. However, further study is required to compare its effectiveness with other risk factors identified through anatomical MRI and ultrasound.

Quantitative MRI-based radiomics analysis identifies blood flow feature associated to overall survival for rectal cancer patients.

Radiomics objectively quantifies image information through numerical metrics known as features. In this study, we investigated the stability of magnetic resonance imaging (MRI)-based radiomics features in rectal cancer using both anatomical MRI and quantitative MRI (qMRI), when different methods to define the tumor volume were used. Second, we evaluated the prognostic value of stable features associated to 5-year progression-free survival (PFS) and overall survival (OS). On a 1.5T MRI scanner, 81 patients underwent diagnostic MRI, an extended diffusion-weighted sequence with calculation of the apparent diffusion coefficient (ADC) and a multiecho dynamic contrast sequence generating both dynamic contrast-enhanced and dynamic susceptibility contrast (DSC) MR, allowing quantification of Ktrans, blood flow (BF) and area under the DSC curve (AUC). Radiomic features were extracted from T2w images and from ADC, Ktrans, BF and AUC maps. Tumor volumes were defined with three methods; machine learning, deep learning and manual delineations. The interclass correlation coefficient (ICC) assessed the stability of features. Internal validation was performed on 1000 bootstrap resamples in terms of discrimination, calibration and decisional benefit. For each combination of image and volume definition, 94 features were extracted. Features from qMRI contained higher prognostic potential than features from anatomical MRI. When stable features (> 90% ICC) were compared with clinical parameters, qMRI features demonstrated the best prognostic potential. A feature extracted from the DSC MRI parameter BF was associated with both PFS (p = 0.004) and OS (p = 0.004). In summary, stable qMRI-based radiomics features was identified, in particular, a feature based on BF from DSC MRI was associated with both PFS and OS.

Role of Histogram Features on Arterial Spin Labeling Perfusion Magnetic Resonance Imaging in Identifying Isocitrate Dehydrogenase Genotypes and Glioma Malignancies.

To explore the use of histogram features on noninvasive arterial spin labeling (ASL) perfusion magnetic resonance imaging (MRI) in differentiating isocitrate dehydrogenase mutant-type (IDH-mut) from isocitrate dehydrogenase wild-type (IDH-wt) gliomas, and lower-grade gliomas (LGGs) from glioblastomas. This retrospective study included 131 patients who underwent ASL MRI and anatomic MRI. Cerebral blood flow (CBF) maps were calculated, from which 10 histogram features describing the CBF distribution were extracted within the tumor region. Correlation analysis was performed to determine the correlations between histogram features as well as tumor grades and IDH genotypes. The independent t-test and Fisher's exact test were used to determine differences in the extracted histogram features, age at diagnosis, and sex in different glioma subtypes. Multivariate binary logistic regression analysis was performed, and diagnostic performances were evaluated with the receiver operating characteristic curves. CBF histogram features were significantly correlated with tumor grades and IDH genotypes. These features can effectively differentiate LGGs from glioblastomas, and IDH-mut from IDH-wt gliomas. The area under the receiving operating characteristic curve of the model calculated using combined CBF 30th percentile and age at diagnosis in differentiating LGGs from glioblastomas was 0.73. Integrating age at diagnosis and CBF 10th percentile could be more effective in differentiating IDH-mut from IDH-wt gliomas. Furthermore, the combined model had a better area under the receiving operating characteristic curve at 0.856 (sensitivity: 84.4%, specificity: 82.9%). The histogram features on ASL were significantly correlated with tumor grade and IDH genotypes. Moreover, the use of these features could effectively differentiate glioma subtypes. The combined application of age at diagnosis and perfusion histogram features resulted in a more comprehensive identification of tumor subtypes. Therefore, ASL can be a noninvasive tool for the pre-surgical evaluation of gliomas.

Association between vertebral artery dominance and basilar artery curvature in migraineurs: an anatomical magnetic resonance imaging study.

Numerous studies demonstrate a link between cerebrovascular alterations and migraine pathogenesis. We investigated the association between migraine and vertebral artery dominance (VAD), basilar artery (BA) curvature, and elongation. This cross-sectional MRI study included 74 migraine patients and 74 control subjects aged between 18 and 55 years. Diameters of the intracranial part of the vertebral artery (VA) and BA, height of the BA bifurcation, and total lateral displacement of the BA were measured. In addition, we investigated the directional relationship between VAD and BA curvature. There were no statistically significant differences between the groups regarding VA and BA diameters and total lateral displacement of the BA. The height of the BA bifurcation was found to be significantly higher in migraine patients compared to controls (p = 0.002). The left-side VAD was more frequent in migraine patients compared to control subjects (60.8% (45/74) vs 41.9% (31/74), p = 0.001). In migraine patients, particularly those with aura (MwA) patients, with left-side VAD, the rate of BA displacement to the right side is significantly higher than those with right-side VAD or non-VAD (p = 0.022). Also, we found that total lateral displacement of the BA is correlated with VA asymmetry in patients with MwA (r = 0.538, p = 0.007). VAD and its opposite-directional relationship with the lateral displacement of the BA may be associated with migraine pathophysiology. Together with aging, this association may contribute to changes in the vertebrobasilar system (VBS) geometry which may result in increased risk for posterior circulation infarction (PCI) in migraineurs.

Early cerebral amyloid-β accumulation and hypermetabolism are associated with subtle cognitive deficits before accelerated cerebral atrophy

AimsAlzheimer’s disease (AD) is characterized by the accumulation of amyloid beta (Aβ) in the brain. The deposition of Aβ is believed to initiate a detrimental cascade, including cerebral hypometabolism, accelerated brain atrophy, and cognitive problems—ultimately resulting in AD. However, the timing and causality of the cascade resulting in AD are not yet fully established. Therefore, we examined whether early Aβ accumulation affects cerebral glucose metabolism, atrophy rate, and age-related cognitive decline before the onset of neurodegenerative disease.MethodsParticipants from the Metropolit 1953 Danish Male Birth Cohort underwent brain positron emission tomography (PET) imaging using the radiotracers [11C]Pittsburgh Compound-B (PiB) (N = 70) and [18F]Fluorodeoxyglucose (FDG) (N = 76) to assess cerebral Aβ accumulation and glucose metabolism, respectively. The atrophy rate was calculated from anatomical magnetic resonance imaging (MRI) scans conducted presently and 10 years ago. Cognitive decline was examined from neurophysiological tests conducted presently and ten or 5 years ago.ResultsHigher Aβ accumulation in AD-critical brain regions correlated with greater visual memory decline (p = 0.023). Aβ accumulation did not correlate with brain atrophy rates. Increased cerebral glucose metabolism in AD-susceptible regions correlated with worse verbal memory performance (p = 0.040).ConclusionsAβ accumulation in known AD-related areas was associated with subtle cognitive deficits. The association was observed before hypometabolism or accelerated brain atrophy, suggesting that Aβ accumulation is involved early in age-related cognitive dysfunction. The association between hypermetabolism and worse memory performance may be due to early compensatory mechanisms adapting for malfunctioning neurons by increasing metabolism.