T2-weighted Magnetic Resonance Research Articles

Modeling the impact of MRI acquisition bias on structural connectomes: Harmonizing structural connectomes.

One way to increase the statistical power and generalizability of neuroimaging studies is to collect data at multiple sites or merge multiple cohorts. However, this usually comes with site-related biases due to the heterogeneity of scanners and acquisition parameters, negatively impacting sensitivity. Brain structural connectomes are not an exception: Being derived from T1-weighted and diffusion-weighted magnetic resonance images, structural connectivity is impacted by differences in imaging protocol. Beyond minimizing acquisition parameter differences, removing bias with postprocessing is essential. In this work we create, from the exhaustive Human Connectome Project Young Adult dataset, a resampled dataset of different b-values and spatial resolutions, modeling a cohort scanned across multiple sites. After demonstrating the statistical impact of acquisition parameters on connectivity, we propose a linear regression with explicit modeling of b-value and spatial resolution, and validate its performance on separate datasets. We show that b-value and spatial resolution affect connectivity in different ways and that acquisition bias can be reduced using a linear regression informed by the acquisition parameters while retaining interindividual differences and hence boosting fingerprinting performance. We also demonstrate the generative potential of our model, and its generalization capability in an independent dataset reflective of typical acquisition practices in clinical settings.

208 - Feasibility of accelerated 3D isotropic high-resolution T2-weighted bladder magnetic resonance imaging using the deep learning-constrained compressed sensitivity encoding technique (SENSE)

208 - Feasibility of accelerated 3D isotropic high-resolution T2-weighted bladder magnetic resonance imaging using the deep learning-constrained compressed sensitivity encoding technique (SENSE)

MRI-based radiomics for stratifying recurrence risk of early-onset rectal cancer: a multicenter study

Early-onset rectal cancer (EORC) is characterized by a unique disease process with different clinicopathological features compared with late-onset rectal cancer (LORC). Research on the risk of recurrence in EORC patients, however, is limited. We aim to develop a predictive model to accurately predict EORC recurrence risk. Rectal cancer patients who underwent radical surgery and T2-weighted imaging and diffusion-weighted imaging magnetic resonance imaging (MRI) were retrospectively enrolled from three medical institutions from November 2012 to November 2018. Differences in clinicopathological characteristics between EORC and LORC were compared. Five prediction models for disease-free survival were constructed based on clinicopathological variables and five radiomic features from pretreatment MRI of the EORC. A fixed cut-off value calculated in the training set was used to stratify EORC patients into high-risk and low-risk groups of post-operative recurrence. Model performance was evaluated by concordance index (C-index) and receiver operating characteristic curve. A total of 264 EORC patients (median age, 43 years, 163 males) and 778 LORC patients (median age, 62 years, 520 males) were enrolled. Pretreatment positive carcinoembryonic antigen [hazard ratio (HR)= 2.84, P= 0.006], pathological positive lymph node status (pN positive) [HR= 2.86, P= 0.011] and MRI-based radiomics score [HR= 2.72, P < 0.001] are independent risk factors for disease-free survival in EORC patients. The EORC-ClinPathRadiom model, constructed by integrating the clinicopathological characteristics and MRI-based radiomics features of EORC, showed C-index of 0.82, 0.82, and 0.81 in the training, internal, and external test sets, respectively. This model effectively stratified EORC patients into high risk and low risk of recurrence (HRs for the training, internal, and external test sets were 8.96, 6.81, and 7.46, respectively). The EORC-ClinPathRadiom model can effectively predict and stratify the risk of post-operative recurrence in EORC patients.

Behavioral Changes and Long-Term Cortical Thickness Alterations in Women with Fibromyalgia

ObjectivesThe purpose of this study was to examine long-term brain and behavioral changes in patients with fibromyalgia (FM) compared to healthy individuals. MethodsData from 33 female volunteers with FM and 33 healthy controls women paired by age and school degree were used to analyze the cortical thickness from high-resolution T1-weighted magnetic resonance imaging (MRI) obtained through a 3T-MRI scanner. Additionally, the Toronto Alexithymia Scale, the Positive and Negative Affect Scale, the emotion regulation questionnaire (ERQ), and the Hamilton Depression and Anxiety rating scales were used to evaluate the behavioral changes. ResultsThe findings indicate significant cortical structure differences in the right cerebral hemisphere between groups in the insular anterior cortex precentral and postcentral gyrus (P < .001). The FM group scored higher for alexithymia (P < .01), negative affect (P < .01), anxiety (P < .01), and depression (P < .01) symptoms, on the other hand, scored lower for positive affect (P < .01). No differences were found on the left cerebral hemisphere. Furthermore, there was a negative correlation between the right insular anterior cortex and Toronto Alexithymia Scale (P < .001). ConclusionThis study showed long-term brain and behavioral changes in patients with FM, suggesting notable neurophysiological alterations associated with this chronic pain condition. It provides new insights into how FM may affect brain health and potential biomarkers for the condition.

Longitudinal association between depressive symptoms and cognitive function: the neurological mechanism of psychological and physical disturbances on memory.

The neural correlates underlying late-life depressive symptoms and cognitive deterioration are largely unclear, and little is known about the role of chronic physical conditions in such association. This research explores both concurrent and longitudinal associations between late-life depressive symptoms and cognitive functions, with examining the neural substrate and chronic vascular diseases (CVDs) in these associations. A total of 4109 participants (mean age = 65.4, 63.0% females) were evaluated for cognitive functions through various neuropsychological assessments. Depressive symptoms were assessed by the Geriatric Depression Scale and CVDs were self-reported. T1-weighted magnetic resonance imaging (MRI), diffusion tensor imaging, and functional MRI (fMRI) data were acquired in a subsample (n = 791). Cognitively, higher depressive symptoms were correlated with poor performance across all cognitive domains, with the strongest association with episodic memory (r = ‒0.138, p < 0.001). Regarding brain structure, depressive symptoms were negatively correlated with thalamic volume and white matter integrity. Further, white matter integrity was found to mediate the longitudinal association between depressive symptoms and episodic memory (indirect effect = -0.017, 95% CI -0.045 to -0.002) and this mediation was only significant for those with severe CVDs (β = -0.177, p = 0.008). This study is one of the first to provide neural evidence elucidating the longitudinal associations between late-life depressive symptoms and cognitive dysfunction. Additionally, the severity of CVDs strengthened these associations, which enlightens the potential of managing CVDs as an intervention target for preventing depressive symptoms-related cognitive decline.

Sagittal morphometry of intervertebral spaces in subaxial cervical region of asymptomatic Chinese.

This study aimed to quantify and evaluate morphology of intervertebral space between neighboring cervical units using radiographic imaging indices, to help spine surgeons when performing anterior cervical discectomy and fusion (ACDF) surgery on the Chinese population. The background and imaging parameters of the subjects were assessed. Cervical lateral radiographs were employed to measure the intervertebral height (IH), intervertebral height index (IHI), and segmental lordosis (SL). Endplate parameters measurements were conducted on sagittal T2-weighted magnetic resonance imaging (MRI), including endplate sagittal diameter (ESD), and endplate concavity depth (ECD). All individuals were divided into three age groups: individuals aged 20-35 were in group A, individuals aged 36-50 were in group B, and individuals aged over 50 were in group C. A comparison of the variables was conducted among the three groups. Additionally, these radiographic parameters were also compared between males and females. A total of 102 individuals were included in this study. IH was greater at C6/7 than those at other segmental levels (p < 0.001). The largest SL values were found at C6/7, while the least were found at C3/4. The superior ESD (ESDs) and ECD (ECDs) of the intervertebral space were significantly greater than those of the inferior endplates (p < 0.05). The ESD and ECD values were the largest at C6/7, while the least at C3/4. Additionally, age and gender had an influence on several parameters. IH was significantly lower in group A compared to group B (p < 0.05) and group C (p < 0.05) from C3/4 level to C6/7 level. ECDs were lower in group A compared to group B (p < 0.05) and group C (p < 0.05) at each level. IH and ESD in males were generally significantly greater than those in females at all levels (p < 0.05). The current study found that C6/7 had the greatest IH, SL, ESD, and ECD values in asymptomatic Chinese. SL gradually increased from C3/4 to C6/7 levels. IH and ECD were significantly associated with age. Males had greater IH and ESD values than females. These findings provide baseline information for planning for selection of anterior screws and intervertebral implants.

T2 Hyperintensities in Children with Neurofibromatosis Type 1

Areas of increased signal intensity, known as T2 hyperintensities (T2Hs), observed on T2-weighted magnetic resonance imaging (MRI) scans, are linked to a spectrum of brain abnormalities in children with neurofibromatosis type 1 (NF1). Defining the radiological characteristics that distinguish non-neoplastic from neoplastic T2Hs in children with NF1 is crucial. Then, we could identify lesions that were most likely to require oncologic surveillance. We conducted a single-center retrospective review of all available brain MRIs from 98 children with NF1 and 50 healthy pediatric controls. All T2Hs identified on MRI were characterized based on location, imaging features, and the presence of lesion-related symptoms. Subsequently, all T2Hs were classified using newly established criteria and categorized into 3 distinct groups: low-risk tumor lesions, medium-risk tumor lesions, and high-risk tumor lesions. Lesions deemed to be high-risk will be recommended for surgical treatment. T2Hs were present in 61 (62.2%) individuals of the NF1 cohort. T2Hs were a highly sensitive (100%; 95% confidence interval 92.9%-100.0%) and specific (62.2%; 95% confidence interval 51.9%-71.8%) marker for the diagnosis of NF1. In children aged 4-10, the detection rate of T2Hs is significantly higher than in children under 4years old and those aged between 10 and 18 (P < 0.05). T2Hs were most frequently located in basal ganglia, cerebellar hemispheres, and brainstem. During the follow-up process, none of the lesions categorized as low-risk or medium-risk tumor lesions progressed to high-risk tumor lesions. Seven patients had high-risk tumor lesions and underwent surgical treatment. The pathological assessment identified 5 cases of glioma among the 7 patients, along with 1 case of gliosis and 1 case of vascular dysplasia. Low-risk and medium-risk tumor lesions can both be classified as unidentified bright objects . Unidentified bright objects constituted the majority of T2Hs in children with NF1. High-risk tumor lesions should be considered as probable tumors. With the application of standardized radiologic criteria, a high prevalence of probable brain tumors will be identified in this at-risk population of children, which underscores the importance of vigilant and appropriate oncological surveillance to ensure timely detection and intervention for these tumors.

Adenosine triphosphate-responsive carbon dots nanoreactors for T1-weighted magnetic resonance imaging-guided tumor chemodynamic therapy

Adenosine triphosphate-responsive carbon dots nanoreactors for T1-weighted magnetic resonance imaging-guided tumor chemodynamic therapy

3-1-3 Weight averaging technique-based performance evaluation of deep neural networks for Alzheimer’s disease detection using structural MRI

Alzheimer’s disease (AD) is a progressive neurological disorder. It is identified by the gradual shrinkage of the brain and the loss of brain cells. This leads to cognitive decline and impaired social functioning, making it a major contributor to dementia. While there are no treatments to reverse AD’s progression, spotting the disease’s onset can have a significant impact in the medical field. Deep learning (DL) has revolutionized medical image classification by automating feature engineering, removing the requirement for human experts in feature extraction. DL-based solutions are highly accurate but demand a lot of training data, which poses a common challenge. Transfer learning (TL) has gained attention for its knack for handling limited data and expediting model training. This study uses TL to classify AD using T1-weighted 3D Magnetic Resonance Imaging (MRI) from the Alzheimer’s Disease Neuroimaging (ADNI) database. Four modified pre-trained deep neural networks (DNN), VGG16, MobileNet, DenseNet121, and NASNetMobile, are trained and evaluated on the ADNI dataset. The 3-1-3 weight averaging technique and fine-tuning improve the performance of the classification models. The evaluated accuracies for AD classification are VGG16: 98.75%; MobileNet: 97.5%; DenseNet: 97.5%; and NASNetMobile: 96.25%. The receiver operating characteristic (ROC), precision–recall (PR), and Kolmogorov-Smirnov (KS) statistic plots validate the effectiveness of the modified pre-trained model. Modified VGG16 excels with area under the curve (AUC) values of 0.99 for ROC and 0.998 for PR curves. The proposed approach shows effective AD classification by achieving high accuracy using the 3-1-3 weight averaging technique and fine-tuning.

Demystifying the challenging diagnosis of post-radiation nasopharyngeal necrosis on multimodality imaging.

Post-radiation nasopharyngeal necrosis (PRNN) is a rare but life-threatening condition that often poses a diagnostic challenge in imaging studies owing to its overlapping features with recurrent nasopharyngeal tumours. We herein describe the characteristic imaging appearance of PRNN on post-contrast T1-weighted magnetic resonance imaging, diffusion-weighted imaging (DWI) and fluorodeoxyglucose (FDG)-PET/CT which may provide insights into its pathological findings.

Evaluation of Trunk Oblique Muscle Activities in Baseball Batters Using T2-Weighted Magnetic Resonance Imaging.

Takuya, Y, Taro, I, Chihiro, K, Mana, O, Takahiro, O, and Masako, H. Evaluation of trunk oblique muscle activities in baseball batters using T2-weighted magnetic resonance imaging. J Strength Cond Res XX(X): 000-000, 2024-This study investigated abdominal oblique muscle activity using T2-weighted imaging in baseball batting. For this purpose, 17 baseball batters (21.6 ± 2.7 years, 173.9 ± 4.0 cm, 77.5 ± 7.6 kg) performed 100 toss-batting trials. Before and after toss-batting, 3 Tesla magnetic resonance imaging scans were performed to obtain the T2 values of the 4 abdominal external and internal oblique muscle pairs. The results showed that the T2 values of all abdominal oblique muscles were significantly increased after the 100 trials (p < 0.05), with no differences in these increases between the muscles. The rate of change in the T2 values was 1.0 ± 3.9% and 4.2 ± 5.2% for the external and internal oblique muscles on the pitcher's side and 3.2 ± 5.1% and 0.9 ± 2.5% for the external and internal oblique muscles on the catcher's side, respectively. These findings indicate that the activity levels of all abdominal oblique muscles during baseball battings are similar and lower than those of the agonist muscles used during resistance exercise and sprinting. These findings suggest that baseball batting is a low-intensity exercise of the abdominal oblique muscles, but adequate training of each abdominal oblique muscle may improve batting performance and prevent injury.

Repeated intrathecal injections of peripheral nerve-derived stem cell spheroids improve outcomes in a rat model of traumatic brain injury

BackgroundTraumatic brain injury (TBI) is a major cause of disability and mortality worldwide. However, existing treatments still face numerous clinical challenges. Building on our prior research showing peripheral nerve-derived stem cell (PNSC) spheroids with Schwann cell-like phenotypes can secrete neurotrophic factors to aid in neural tissue regeneration, we hypothesized that repeated intrathecal injections of PNSC spheroids would improve the delivery of neurotrophic factors, thereby facilitating the restoration of neurological function and brain tissue repair post-TBI.MethodsWe generated PNSC spheroids from human peripheral nerve tissue using suspension culture techniques. These spheroids were characterized using flow cytometry, immunofluorescence, and reverse-transcription polymerase chain reaction. The conditioned media were evaluated in SH-SY5Y and RAW264.7 cell lines to assess their effects on neurogenesis and inflammation. To simulate TBI, we established a controlled cortical impact (CCI) model in rats. The animals were administered intrathecal injections of PNSC spheroids on three occasions, with each injection spaced at a 3-day interval. Recovery of sensory and motor function was assessed using the modified neurological severity score (mNSS) and rotarod tests, while histological (hematoxylin and eosin, Luxol fast blue staining) and T2-weighted magnetic resonance imaging analyses, alongside immunofluorescence, were conducted to evaluate the recovery of neural structures and pathophysiology.ResultsPNSC spheroids expressed high levels of Schwann cell markers and neurotrophic factors, such as neurotrophin-3 and Ephrin B3. Their conditioned medium was found to promote neurite outgrowth, reduce reactive oxygen species-mediated cell death and inflammation, and influence M1-M2 macrophage polarization. In the CCI rat model, rats receiving repeated triple intrathecal injections of PNSC spheroids showed significant improvements in sensory and motor function, with considerable neural tissue recovery in damaged areas. Notably, this treatment promoted nerve regeneration, axon regrowth, and remyelination. It also reduced glial scar formation and inflammation, while encouraging angiogenesis.ConclusionOur findings suggest that repeated intrathecal injections of PNSC spheroids can significantly enhance neural recovery after TBI. This effect is mediated by the diverse neurotrophic factors secreted by PNSC spheroids. Thus, the strategy of combining therapeutic cell delivery with multiple intrathecal injections holds promise as a novel clinical treatment for TBI recovery.

Multi-Chambered Core/Shell Supraparticles for Real-Time, Full-Time Diagnosis and Treatment Integration of Tumors.

To a certain extent, theranostic nanoplatforms promote tumor treatment efficiency. However, timely monitoring of the critical stages and signal sustainability of the entire process is challenging. In this study, multi-chambered core/shell magnetic nanoparticles (MC-MNPs) as drug and imaging agent multi-loaded nanocarriers with a synergistic release function are reported. Supraparticles with stable chambers are formed by the supercooling self-assembly of several core/shell magnetic nanoparticles composed of amphiphilic copolymers as the core and hydrophilic magnetic iron oxide nanoparticles as the shell. Desalinized doxorubicin and coumarin 6 are stored in different cavities of nanocarriers, and chitosan is used as an outer encapsulation layer. Based on their construction properties, MC-MNPs can exhibit gradient-degraded and steady-released controllability in the tumor environment. Furthermore, real-time accumulation situations and full-time diagnostic signals of nanocarriers are thoroughly demonstrated using fluorescence imaging and T2-weighted magnetic resonance imaging before and after magnetic hyperthermia in targeted tumors under an alternating magnetic field. Thus, MC-MNPs as theranostic nanocarriers exhibit great potential for the timely monitoring and full-time guidance of tumor treatment.

Targeted delivery of cisplatin magnetic nanoparticles for diagnosis and treatment of nasopharyngeal carcinoma

Rapid advances in nanotechnology are paving the way for innovative breakthroughs in overcoming the current limitations in the clinical treatment of cancer and other prevalent diseases plaguing mankind. Magnetic nanoparticles composed of iron oxide (Fe3O4) are a novel class of nanoparticles that are receiving increasing attention in the field of cancer therapy. To address the inherent limitations, bare Fe3O4 can be functionalized, polymerized, assembled, or combined with other functional materials to produce a range of smart nanoplatforms suitable for tumor therapy. In this paper, we present a unique multifunctional therapeutic nanoplatform centered on aldehyde-oxidized sodium alginate-stabilized iron oxide nanoparticles (NPs) designed for T2-weighted magnetic resonance (MR) imaging. Sodium alginate oxide and ferric oxide nanoparticles were prepared respectively, and the two particles were mixed in a certain molar ratio to form a complex, which was coupled to target polypeptide GE11 by Schiff base reaction, and finally supported by cisplatin through coordination complexation. The prepared magnetic nanoparticles (hereinafter referred to as GE11-CDDP-ASA@Fe3O4) have an average diameter of 152.9 nm, and have good colloidal stability and cytocompatibility. The distinctive structure and composition of GE11-CDDP-ASA@Fe3O4 contribute to its excellent MRI imaging performance, positioning it as a nano platform suitable for enhancing the efficacy of combination therapy in tumor treatment. This is of great significance for translational nanomedicine applications.

Advancements in opportunistic intracranial aneurysm screening: The impact of a deep learning algorithm on radiologists' analysis of T2-weighted cranial MRI

(1) Background: Unruptured Intracranial Aneurysms (UIAs) are common blood vessel malformations, occurring in up to 3 % of healthy adults. Magnetic Resonance Angiography (MRA) is frequently used for the screening of UIAs due to its high resolution in vascular anatomy. However, T2-Weighted Magnetic Resonance Imaging (T2WI) is a standard sequence utilized for the majority of outpatient head scans. By employing a sequence such as T2WI, there is a possible shift towards early detection of UIAs through opportunistic screening. Here, we assess a Deep Learning Algorithm (DLA) developed to assist radiologists in identifying and reporting UIAs on T2WI in a routine clinical setting. (2) Methods: A DLA was trained on a set of 110 patients undergoing an MR head scan with the gold standard set by two radiology experts. Eight radiologists were given a cohort of 50 cranial T2WI studies and asked for a routine report. After a 10-day washout period, they reviewed the same cases randomized and supported by the DLA predictions. We assessed changes in sensitivity, specificity, accuracy, and false positives. (3) Results: During routine reporting, the models’ assistance improved the sensitivity of the eight participants by an average of 36.19 and the accuracy by 10.00 percentage points. (4) Conclusion: Our results indicate the potential benefit of deep learning to improve radiologists' detection of UIAs during routine reporting. From this, we can infer that the combination of T2WI with our DLA supports opportunistic screening, suggesting potential approaches for future research and application.

Rational Design of a Hetero-multinuclear Gadolinium(III)-Copper(II) Complex: Integrating Magnetic Resonance Imaging, Photoacoustic Imaging, Mild Photothermal Therapy, Chemotherapy and Immunotherapy of Cancer.

For more accurate diagnosis and effective treatment of cancer, we proposed to develop a hetero-multinuclear metal complex based on the property of apoferritin (AFt) for targeting tumor theranostics by integrating dual-modality imaging diagnosis and multimodality therapy. To this end, we rational designed and synthesized a trinuclear Gd(III)-Cu(II) thiosemicarbazone complex (Gd-2Cu) and then constructed a Gd-2Cu@AFt nanoparticle (NP) delivery system. Gd-2Cu/Gd-2Cu@AFt NPs not only had significant T1-weighted magnetic resonance imaging and photoacoustic imaging of the tumor but also effectively inhibited tumor growth through a combination of mild photothermal therapy, chemotherapy, and immunotherapy. Gd-2Cu@AFt NPs optimized the behavior of imaging diagnosis and therapy of Gd-2Cu, improved its targeting ability, and reduced the side effects in vivo. Besides, we revealed and clarified the anticancer mechanism of Gd-2Cu: interrupting energy metabolism of the tumor cell, inducing apoptosis of the tumor cell, and activating a systemic immune response by inducing immunogenic cell death of cancer cells.

Incidence of Tethered Cord Syndrome in Pediatric Patients With Neurofibromatosis Type 1

ObjectiveThe link between Tethered Cord Syndrome (TCS) and Neurofibromatosis Type 1 (NF1) remains unclear. To date, only two studies have indicated a high occurrence of TCS in the pediatric NF1 patient population. Our study aims to ascertain the incidence of TCS among Chinese pediatric patients with NF1. MethodsA single-institution, 8-year retrospective analysis at a tertiary-level children's hospital was conducted for patients with NF1 who underwent surgery for TCS. The clinical features, imaging characteristics, genetic testing outcomes, and histopathological findings of pediatric NF1 patients with TCS were analyzed. ResultsDuring the study period, a total of 115 pediatric patients were diagnosed with NF1. Among these 115 NF1 patients, 11 individuals, accounting for 9.6% of the sample, were confirmed to have TCS. This rate of occurrence is significantly higher than the incidence rate of TCS in the general population, which stands at 0.17%. All 11 of the pediatric NF1 patients underwent surgery for TCS. Out of the 11 patients who were advised to have tethered cord release surgery, 4 (which is 36.4%) were girls, and the average age of these 11 patients was 8.6 years old, with ages ranging from 2 to 17 years old. The conus medullaris position of the 11 pediatric NF1 patients ranged from L1 to L2, and 10 of them (91%) had a filum terminale lipoma, characterized by high signal intensity on T1-weighted magnetic resonance (MR) images. Another patient was diagnosed with Occult Tethered Cord Syndrome (OTCS). All 11 pediatric NF1 patients exhibited symptoms associated with TCS, such as neuromotor dysfunction, abnormalities in urination, defecation, skeletal system abnormalities, or pain. Eight of the 11 pediatric NF1 patients had undergone genetic testing, which is a crucial part of the diagnostic process for NF1. The histopathological examination of the 11 pediatric NF1 patients who underwent surgery revealed that 10 patients had fatty infiltration of the filum terminale (FT), while the remaining patient exhibited fibrosis of the filum terminale (FT). ConclusionsIn the group of pediatric patients with NF1, the incidence of TCS, presenting to the pediatric neurosurgery clinic for any reason, is significantly higher than that of the general population. However, the pathophysiological relationship between NF1 and TCS is still not clear. It is essential to provide counseling to NF1 patients and their families about the symptoms of TCS to make sure they are aware and can seek the necessary care when needed. This underscores the importance of not only diagnosing NF1 but also staying alert for related conditions like TCS, which may have a higher occurrence in this demographic.

Depth of Hydrogel Spacer Rectal Wall Infiltration Was Not Associated With Rectal Toxicity: Results From a Randomized Prospective Trial

Rectal spacers have gained popularity as a dose-sparing material for prostate cancer radiation therapy (RT). However, the procedure can be associated with unintended rectal wall infiltration (RWI) of the spacer gel. We therefore classified RWI severity as a function of depth and explored its association with rectal toxicity using a data set from prostate cancer patients treated with RT on a prospective randomized clinical trial (RCT). Postimplant T2-weighted magnetic resonance images of 149 subjects randomized to the hydrogel spacer arm of a published multicenter RCT were assessed for the presence and depth of RWI. All implants were assigned a score of 0 (no rectal wall signal changes), 1 (rectal wall edema/signal change), 2 (partial RWI), or 3 (full-thickness RWI); RWI was defined as a score of 2 or 3. Correlations were made between RWI score and physician-reported procedure, acute, and late rectal toxicity. Although 62.4% of implants had no rectal wall signal abnormalities, 24% [scores of 2 (20.1%) and 3 (4.0%)] of procedures exhibited radiographic evidence of RWI. Full-thickness RWI was associated with both a longer length (22.8 ± 7.0 mm, P = .008) and a larger circumferential percentage (35.8% ± 9.2%, P = .045) of rectal infiltration. Although 7 subjects (5%) experienced transient procedure-related rectal toxicities (most commonly perineal/rectal pain), only one had RWI (score of 2, National Cancer Institute's Common Terminology Criteria for Adverse Events grade 1). Consequently, no correlation was observed between procedural rectal toxicity and the presence/extent of RWI (P = .64). Similarly, no difference in acute (P = .64) or late (P = .85) rectal toxicity incidence or grade was detected between RWI categories; none of the 6 men with a RWI score of 3 developed late rectal toxicity by 15 months. Based on data from an RCT, RWI did not contribute to increased rectal toxicity prior and up to 15 months after conventional prostate cancer RT.

Hypertension and cerebral blood flow in the development of Alzheimer's disease.

We investigated the interactive associations between amyloid and hypertension on the entorhinal cortex (EC) tau and atrophy and the role of cerebral blood flow (CBF) as a shared mechanism by which amyloid and hypertension contribute to EC tau and regional white matter hyperintensities (WMHs). We analyzed data from older adults without dementia participating in the Add-Tau study (NCT02958670, n=138) or Alzheimer's Disease Neuroimaging Initiative (ADNI) (n=523) who had available amyloid-positron emission tomography (PET), tau-PET, fluid-attenuated inversion recovery (FLAIR), and T1-weighted magnetic resonance imaging (MRI). A subsample in both cohorts had available arterial spin labeling (ASL) MRI (Add-Tau: n=78; ADNI: n=89). The detrimental effects of hypertension on AD pathology and EC thickness were more pronounced in the Add-Tau cohort. Increased amyloid burden was associated with decreased occipital gray matter CBF in the ADNI cohort. In both cohorts, lower regional gray matter CBF was associated with higher EC tau and posterior WMH burden. Reduced cerebral perfusion may be one common mechanism through which hypertension and amyloid are related to increased EC tau and WMH volume. Hypertension is associated with increased entorhinal cortex (EC) tau, particularly in the presence of amyloid. Decreased cortical cerebral blood flow (CBF) is associated with higher regional white matter hyperintensity volume. Increasing amyloid burden is associated with decreasing CBF in the occipital lobe. MTL CBF and amyloid are synergistically associated with EC tau.

Comparative analysis of cortical anatomy inmale participants with internet gaming disorder or tobacco use disorder: Insights fromnormative modeling.

Research on individual differences in brain structural features of internet gaming disorder (IGD) and established addictions such as tobacco use disorder (TUD) is currently limited. This study utilized normative modeling to analyze the cortical thickness (CT) development patterns of male patients with IGD and TUD, aiming to provide further insights into whether IGD qualifies as an addiction. Surface-based brain morphometry (SBM) was used to calculate CT from T1-weighted magnetic resonance imaging data of 804 male participants (665 healthy individuals, 68 IGD and 71 TUD). Gaussian process regression was employed to generate normative models of CT development. Deviation maps were produced to depict deviations of IGD and TUD participants from the typical developmental patterns. Both addiction groups exhibited widespread cortical thinning, particularly in regions such as the bilateral temporal pole and medial orbitofrontal cortex. The TUD group demonstrated a higher degree of individualization and limited spatial overlap compared to the IGD group. Opposite trends in CT changes were observed between the two groups in the bilateral pericalcarine cortex and pars triangularis. These findings regarding the similarities and differences between IGD and TUD provide support for the idea that IGD shares common features with substance-related addictions and contribute to a deeper understanding of the neural mechanisms underlyingIGD.