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PURPOSE: To quantify the radiation dose distribution and lesion morphometry (shape) at baseline, prior to chemoradiation, and at the time of radiographic recurrence in patients with glioblastoma (GBM). METHODS: The IMRT dose distribution, location of the center of mass, sphericity, and solidity of the contrast enhancing tumor at baseline and the time of tumor recurrence was quantified in 48 IDH wild-type GBM who underwent postoperative IMRT (2 Gy daily for total of 60 Gy) with concomitant and adjuvant temozolomide. RESULTS: Average radiation dose within enhancing tumor at baseline and recurrence was ≥ 60 Gy. Centroid location of the enhancing tumor shifted an average of 11.3 mm at the time of recurrence with respect to pre-IMRT location. A positive correlation was observed between change in centroid location and PFS in MGMT methylated patients (P = 0.0007) and Cox multivariate regression confirmed centroid distance from baseline was associated with PFS when accounting for clinical factors (P = 0.0189). Lesion solidity was higher at recurrence compared to baseline (P = 0.0118). Tumors that progressed > 12 weeks after IMRT were significantly more spherical (P = 0.0094). CONCLUSION: Most GBMs recur local within therapeutic IMRT doses; however, tumors with longer PFS occurred further from the original tumor location and were more solid and/or nodular.
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Neoplasias Encefálicas , Glioblastoma , Humanos , Glioblastoma/diagnóstico por imagen , Glioblastoma/terapia , Glioblastoma/patología , Neoplasias Encefálicas/diagnóstico por imagen , Neoplasias Encefálicas/terapia , Neoplasias Encefálicas/patología , Recurrencia Local de Neoplasia/patología , Temozolomida/uso terapéutico , Dosis de Radiación , Antineoplásicos Alquilantes/uso terapéuticoRESUMEN
The superior colliculus (SC) is a layered midbrain structure involved in directing both head and eye movements and coordinating visual attention. Although a retinotopic organization for the mediation of saccadic eye-movements has been shown in monkey SC, in human SC the topography of saccades has not been confirmed. Here, a novel experimental paradigm was performed by five participants (one female) while high-resolution (1.2-mm) functional magnetic resonance imaging was used to measure activity evoked by saccadic eye movements within human SC. Results provide three critical observations about the topography of the SC: (1) saccades along the superior-inferior visual axis are mapped across the medial-lateral anatomy of the SC; (2) the saccadic eye-movement representation is in register with the retinotopic organization of visual stimulation; and (3) activity evoked by saccades occurs deeper within SC than that evoked by visual stimulation. These approaches lay the foundation for studying the organization of human subcortical - and enhanced cortical mapping - of eye-movement mechanisms.
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Atención/fisiología , Mapeo Encefálico/métodos , Movimientos Sacádicos/fisiología , Colículos Superiores/fisiología , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Estimulación Luminosa , Percepción Visual/fisiologíaRESUMEN
An unresolved debate in Alzheimer's disease (AD) is whether amyloid plaques are pathogenic, causing overt physical disruption of neural circuits, or protective, sequestering soluble forms of amyloid-ß (Aß) that initiate synaptic damage and cognitive decline. Few animal models of AD have been capable of isolating the relative contribution made by soluble and insoluble forms of Aß to the behavioral symptoms and biochemical consequences of the disease. Here we use a controllable transgenic mouse model expressing a mutant form of amyloid precursor protein (APP) to distinguish the impact of soluble Aß from that of deposited amyloid on cognitive function and synaptic structure. Rapid inhibition of transgenic APP modulated the production of Aß without affecting pre-existing amyloid deposits and restored cognitive performance to the level of healthy controls in Morris water maze, radial arm water maze, and fear conditioning. Selective reduction of Aß with a γ-secretase inhibitor provided similar improvement, suggesting that transgene suppression restored cognition, at least in part by lowering Aß. Cognitive improvement coincided with reduced levels of synaptotoxic Aß oligomers, greater synaptic density surrounding amyloid plaques, and increased expression of presynaptic and postsynaptic markers. Together these findings indicate that transient Aß species underlie much of the cognitive and synaptic deficits observed in this model and demonstrate that significant functional and structural recovery can be attained without removing deposited amyloid.
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Enfermedad de Alzheimer , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Trastornos del Conocimiento/genética , Trastornos del Conocimiento/metabolismo , Sinapsis/patología , Alanina/administración & dosificación , Alanina/análogos & derivados , Enfermedad de Alzheimer/complicaciones , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/patología , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Precursor de Proteína beta-Amiloide/genética , Animales , Azepinas/administración & dosificación , Trastornos del Conocimiento/terapia , Modelos Animales de Enfermedad , Doxiciclina/farmacología , Conducta Exploratoria/efectos de los fármacos , Conducta Exploratoria/fisiología , Humanos , Aprendizaje por Laberinto/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Mutación , Placa Amiloide/inducido químicamente , Placa Amiloide/metabolismo , Sinapsis/efectos de los fármacosRESUMEN
Alzheimer's disease (AD) is associated with an elevated risk for seizures that may be fundamentally connected to cognitive dysfunction. Supporting this link, many mouse models for AD exhibit abnormal electroencephalogram (EEG) activity in addition to the expected neuropathology and cognitive deficits. Here, we used a controllable transgenic system to investigate how network changes develop and are maintained in a model characterized by amyloid ß (Aß) overproduction and progressive amyloid pathology. EEG recordings in tet-off mice overexpressing amyloid precursor protein (APP) from birth display frequent sharp wave discharges (SWDs). Unexpectedly, we found that withholding APP overexpression until adulthood substantially delayed the appearance of epileptiform activity. Together, these findings suggest that juvenile APP overexpression altered cortical development to favor synchronized firing. Regardless of the age at which EEG abnormalities appeared, the phenotype was dependent on continued APP overexpression and abated over several weeks once transgene expression was suppressed. Abnormal EEG discharges were independent of plaque load and could be extinguished without altering deposited amyloid. Selective reduction of Aß with a γ-secretase inhibitor has no effect on the frequency of SWDs, indicating that another APP fragment or the full-length protein was likely responsible for maintaining EEG abnormalities. Moreover, transgene suppression normalized the ratio of excitatory to inhibitory innervation in the cortex, whereas secretase inhibition did not. Our results suggest that APP overexpression, and not Aß overproduction, is responsible for EEG abnormalities in our transgenic mice and can be rescued independently of pathology.
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Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/fisiopatología , Precursor de Proteína beta-Amiloide/genética , Corteza Cerebral/fisiopatología , Electroencefalografía , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Animales , Modelos Animales de Enfermedad , Entropía , Femenino , Técnicas de Sustitución del Gen , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Modelos Neurológicos , Inhibición Neural/fisiología , Presenilina-1/genética , Convulsiones/inducido químicamente , Convulsiones/fisiopatología , Supresión Genética , Transgenes/fisiologíaRESUMEN
PURPOSE: To explore interpretable machine learning (ML) methods, with the hope of adding more prognosis value, for predicting survival for patients with Oropharyngeal-Cancer (OPC). METHODS: A cohort of 427 OPC patients (Training 341, Test 86) from TCIA database was analyzed. Radiomic features of gross-tumor-volume (GTV) extracted from planning CT using Pyradiomics, and HPV p16 status, etc. patient characteristics were considered as potential predictors. A multi-level dimension reduction algorithm consisting of Least-Absolute-Selection-Operator (Lasso) and Sequential-Floating-Backward-Selection (SFBS) was proposed to effectively remove redundant/irrelevant features. The interpretable model was constructed by quantifying the contribution of each feature to the Extreme-Gradient-Boosting (XGBoost) decision by Shapley-Additive-exPlanations (SHAP) algorithm. RESULTS: The Lasso-SFBS algorithm proposed in this study finally selected 14 features, and our prediction model achieved an area-under-ROC-curve (AUC) of 0.85 on the test dataset based on this feature set. The ranking of the contribution values calculated by SHAP shows that the top predictors that were most correlated with survival were ECOG performance status, wavelet-LLH_firstorder_Mean, chemotherapy, wavelet-LHL_glcm_InverseVariance, tumor size. Those patients who had chemotherapy, with positive HPV p16 status, and lower ECOG performance status, tended to have higher SHAP scores and longer survival; who had an older age at diagnosis, heavy drinking and smoking pack year history, tended to lower SHAP scores and shorter survival. CONCLUSION: We demonstrated predictive values of combined patient characteristics and imaging features for the overall survival of OPC patients. The multi-level dimension reduction algorithm can reliably identify the most plausible predictors that are mostly associated with overall survival. The interpretable patient-specific survival prediction model, capturing correlations of each predictor and clinical outcome, was developed to facilitate clinical decision-making for personalized treatment.
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Neoplasias Orofaríngeas , Infecciones por Papillomavirus , Oncología por Radiación , Humanos , Infecciones por Papillomavirus/complicaciones , Neoplasias Orofaríngeas/radioterapia , Aprendizaje AutomáticoRESUMEN
OBJECTIVE: Although seizures are a relatively common phenomenon in the setting of brain metastases (BMs), there are no discrete recommendations regarding the use of antiepileptic drugs (AEDs) in this population, either in general or in the context of treatment. The authors' aim was to better understand the underlying pathological factors as well as the therapeutic techniques that may lead to seizures following the radiosurgical treatment of BMs with the goal of guiding appropriate AED prophylaxis. METHODS: Adult patients with BMs diagnosed from 2013 to 2020 at a single academic institution and treated with radiation therapy were included in this study. The authors evaluated factors associated with the incidence of seizures throughout the disease course, with a focus on seizures in the 90-day period following stereotactic radiosurgery (SRS). RESULTS: Four hundred forty-four patients with newly diagnosed BMs were identified, 10% of whom had seizures at the time of presentation and 28% of whom had a seizure at any point during the study period. Tumor histology was significantly associated with initial seizure risk. AED use was highly variable. In the 90-day post-SRS period, the summed total planning target volume (PTV) was independently predictive of post-SRS seizures, regardless of the fractionation scheme (single fraction vs hypofractionated) and other clinical factors. The number of supratentorial BMs was not predictive of post-SRS seizures. CONCLUSIONS: PTV is a superior predictor of post-SRS seizures relative to the number of supratentorial BMs, as it serves as a volumetric proxy for intracranial disease burden. A larger PTV, alongside tumor histology and prior seizure history, should be considered in the decision-making process for AED use following radiosurgery.
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Neoplasias Encefálicas , Radiocirugia , Adulto , Humanos , Radiocirugia/efectos adversos , Radiocirugia/métodos , Estudios Retrospectivos , Convulsiones/cirugía , Neoplasias Encefálicas/secundario , Anticonvulsivantes/uso terapéuticoRESUMEN
Autosegmentation of gross tumor volumes holds promise to decrease clinical demand and to provide consistency across clinicians and institutions for radiation treatment planning. Additionally, autosegmentation can enable imaging analyses such as radiomics to construct and deploy large studies with thousands of patients. Here, we review modern results that utilize deep learning approaches to segment tumors in 5 major clinical sites: brain, head and neck, thorax, abdomen, and pelvis. We focus on approaches that inch closer to clinical adoption, highlighting winning entries in international competitions, unique network architectures, and novel ways of overcoming specific challenges. We also broadly discuss the future of gross tumor volumes autosegmentation and the remaining barriers that must be overcome before widespread replacement or augmentation of manual contouring.
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Neoplasias , Oncología por Radiación , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Neoplasias/diagnóstico por imagen , Neoplasias/radioterapia , Planificación de la Radioterapia Asistida por Computador/métodosRESUMEN
Purpose: For a cohort of prostate cancer patients treated on an MR-guided radiotherapy (MRgRT) system, we retrospectively analyzed urethral interfractional geometric and dosimetric variations based on onboard MRIs acquired at different timepoints and evaluated onboard prostatic urethra visualization for urethra-focused online adaptive RT. Methods: Twenty-six prostate cancer patients were prospectively scanned on a 0.35-T MRgRT system using an optimized T2-weighted HASTE sequence at simulation and final fraction. Two radiation oncologists (RO1 and RO2) contoured the urethras on all HASTE images. The simulation and final fraction HASTE images were rigidly registered, and urethral interobserver and interfractional geometric variation was evaluated using the 95th percentile Hausdorff distance (HD95), mean distance to agreement (MDA), center-of-mass shift (COMS), and DICE coefficient. For dosimetric analysis, simulation and final fraction HASTE images were registered to the 3D bSSFP planning MRI and 3D bSSFP final setup MRI, respectively. Both ROs' urethra contours were transferred from HASTE images for initial treatment plan optimization and final fraction dose estimation separately. Stereotactic body radiotherapy (SBRT) plans, 40 Gy in 5 fractions, were optimized to meet clinical constraints, including urethral V42Gy ≤0.03 cc, on the planning MRI. The initial plan was then forward calculated on the final setup MRI to estimate urethral dose on the final fraction and evaluate urethral dosimetric impact due to anatomy change. Results: The average interobserver HD95, MDA, COMS, and DICE were 2.85 ± 1.34 mm, 1.02 ± 0.36 mm, 3.16 ± 1.61 mm, and 0.58 ± 0.15, respectively. The average interfractional HD95, MDA, COMS, and DICE were 3.26 ± 1.54 mm, 1.29 ± 0.54 mm, 3.34 ± 2.01 mm, and 0.49 ± 0.18, respectively. All patient simulation MRgRT plans met all clinical constraints. For RO1 and RO2, 23/26 (88%) and 21/26 (81%) patients' final fraction estimated urethral dose did not meet the planned constraint. The average urethral V42Gy change was 0.48 ± 0.58 cc. Conclusion: Urethral interfractional motion and anatomic change can result in daily treatment violating urethral constraints. Onboard MRI with good visualization of the prostatic urethra can be a valuable tool to help better protect the urethra through patient setup or online adaptive RT.
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Radiation oncology practices use a suite of dedicated software and hardware that are not common to other medical subspecialties, making radiation treatment history inaccessible to colleagues. A radiation dose distribution map is generated for each patient internally that allows for visualization of the dose given to each anatomic structure volumetrically; however, this crucial information is not shared systematically to multidisciplinary medical, surgery, and radiology colleagues. A framework was developed in which dose distribution volumes are uploaded onto the medical center's picture archiving and communication system (PACS) to rapidly retrieve and review exactly where, when, and to what dose a lesion or structure was treated. The ability to easily visualize radiation therapy information allows radiology clinics to incorporate radiation dose into image interpretation without direct access to radiation oncology planning software and data. Tumor board discussions are simplified by incorporating radiation therapy information collectively in real time, and daily onboard imaging can also be uploaded while a patient is still undergoing radiation therapy. Placing dose distribution information into PACS facilitates central access into the electronic medical record and provides a succinct visual summary of a patient's radiation history for all medical providers. More broadly, the radiation dose map provides greater visibility and facilitates incorporation of a patient's radiation history to improve oncologic decision making and patient outcomes. Keywords: Brain/Brain Stem, CNS, MRI, Neuro-Oncology, Radiation Effects, Radiation Therapy, Radiation Therapy/Oncology, Radiosurgery, Skull Base, Spine, Technology Assessment Supplemental material is available for this article. © RSNA, 2021 See also commentary by Khandelwal and Scarboro in this issue.
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Registros Electrónicos de Salud , Sistemas de Información Radiológica , Humanos , Imagen por Resonancia Magnética , Dosis de Radiación , Programas InformáticosRESUMEN
PURPOSE: To evaluate urethral contours from two optimized urethral MRI sequences with an MR-guided radiotherapy system (MRgRT). METHODS: Eleven prostate cancer patients were scanned on a MRgRT system using optimized urethral 3D HASTE and 3D TSE. A resident radiation oncologist contoured the prostatic urethra on the patients' planning CT, diagnostic 3T T2w MRI, and both urethral MRIs. An attending radiation oncologist reviewed/edited the resident's contours and additionally contoured the prostatic urethra on the clinical planning MRgRT MRI (bSSFP). For each image, the resident radiation oncologist, attending radiation oncologist, and a senior medical physicist qualitatively scored the prostatic urethra visibility. Using MRgRT 3D HASTE-based contouring workflow as baseline, prostatic urethra contours drawn on CT, diagnostic MRI, clinical bSSFP and 3D TSE were evaluated relative to the contour on 3D HASTE using 95th percentile Hausdorff distance (HD95), mean-distance-to-agreement (MDA), and DICE coefficient. Additionally, prostatic urethra contrast-to-noise-ratios (CNR) were calculated for all images. RESULTS: For two out of three observers, the urethra visibility score for 3D HASTE was significantly higher than CT, and clinical bSSFP, but was not significantly different from diagnostic MRI. The mean HD95/MDA/DICE values were 11.35 ± 3.55 mm/5.77 ± 2.69 mm/0.07 ± 0.08 for CT, 7.62 ± 2.75 mm/3.83 ± 1.47 mm/0.12 ± 0.10 for CT + diagnostic MRI, 5.49 ± 2.32 mm/2.18 ± 1.19 mm/0.35 ± 0.19 for 3D TSE, and 6.34 ± 2.89 mm/2.65 ± 1.31 mm/0.21 ± 0.12 for clinical bSSFP. The CNR for 3D HASTE was significantly higher than CT, diagnostic MRI, and clinical bSSFP, but was not significantly different from 3D TSE. CONCLUSION: The urethra's visibility scores showed optimized urethral MRgRT 3D HASTE was superior to the other tested methodologies. The prostatic urethra contours demonstrated significant variability from different imaging and workflows. Urethra contouring uncertainty introduced by cross-modality registration and sub-optimal imaging contrast may lead to significant treatment degradation when urethral sparing is implemented to minimize genitourinary toxicity.
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Cancer patients are faced with increasing options for cancer care, especially with the introduction of cancer immunotherapy with immune checkpoint inhibitors (ICIs). Though many patients turn to online resources to supplement their decision-making, it is unknown whether online resources in cancer immunotherapy with ICIs are written at an appropriate level of readability according to national medical organizations. We performed a cross-sectional analysis of internet search behavior for cancer immunotherapy by ICIs and clinical trial availability per ClinicalTrials.gov in the United States (US) from 2004 - 2018 with subsequent quantitation of readability by four readability formulas of top 50 online resources. Internet search behavior for "cancer immunotherapy" has steadily increased since 2013 and coincides with the year of the US Food and Drug Administration (FDA) approval for individual ICIs. Furthermore, internet search behavior was significantly correlated with clinical trial availability in the US (R = 0.97, p < 0.0001). None of the top 50 resources available to patients were found to be within the recommended level of sixth-grade readability or less with only one (2%) written at the middle school level, 21 (42%) at the high school level, 23 (46%) at the university level, and five (8%) at a graduate level. Population-level internet search patterns may reflect patient behavior in seeking relevant online health information and may be influenced by new options for cancer therapy, including via clinical trials. However, low readability of available online resources may impede patient comprehension and negatively affect medical decision-making.
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BACKGROUND: Although lobectomy is the standard of care in stage I non-small cell lung cancer (NSCLC), medical comorbidities increase surgical risk in elderly patients. No population-based studies compare short-term mortality (STM) for surgery (STM-S), radiation (STM-R), and observation (STM-O) in elderly patients with stage I NSCLC. METHODS: A total of 60,466 biopsy-proven stage I NSCLC cases diagnosed between 2004 and 2012 were retrieved from the Surveillance, Epidemiology, and End Results Program. Patient characteristics were compared using χ test. Age was divided into 5-year subsets (60 to 64 to 90+ y) for analysis. Similar to other series, STM was defined as death within 2 months of diagnosis. Univariate and multivariate analysis for STM was performed using odds ratio, Kaplan-Meier actuarial method, and Cox proportional hazard ratio. RESULTS: In younger patients, STM-S rates are lower compared with STM-R (1.6% vs. 3.4% in patients 60 to 64 y, P<0.001). However, STM-S rates surpass STM-R with increasing age (up to 8.1% vs. 2.3% in patients 90+ y, P<0.001) becoming significant in the 75- to 79-year age group (4.7% vs. 2.2%, P<0.001). There is an inflection point in the 65- to 69-year age group where STM-S and STM-R rates are similar (2.6% vs. 3.0%, P=0.090). STM for observation reflected the poor health of this cohort with high STM rates in all age groups (19.5% for age 60 to 64 y to 25.3% for age 90+ y, P=0.005). Sex, race, Hispanic ethnicity, age group, and treatment were associated with higher STM on the multivariable analysis (all P<0.001). CONCLUSION: STM in elderly stage I NSCLC patients treated with surgery increases with advancing age but remains stable for patients receiving radiation. Given the success of stereotactic body radiation therapy, radiation should be considered for patients with high STM risk associated with surgery.
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Carcinoma de Pulmón de Células no Pequeñas/mortalidad , Carcinoma de Pulmón de Células no Pequeñas/patología , Consentimiento Informado , Neoplasias Pulmonares/mortalidad , Neoplasias Pulmonares/patología , Anciano , Anciano de 80 o más Años , Biopsia con Aguja , Carcinoma de Pulmón de Células no Pequeñas/radioterapia , Carcinoma de Pulmón de Células no Pequeñas/cirugía , Estudios de Cohortes , Toma de Decisiones Conjunta , Supervivencia sin Enfermedad , Femenino , Evaluación Geriátrica , Humanos , Inmunohistoquímica , Estimación de Kaplan-Meier , Neoplasias Pulmonares/radioterapia , Neoplasias Pulmonares/cirugía , Masculino , Persona de Mediana Edad , Análisis Multivariante , Invasividad Neoplásica/patología , Estadificación de Neoplasias , Neumonectomía/métodos , Neumonectomía/mortalidad , Pronóstico , Modelos de Riesgos Proporcionales , Radiocirugia/métodos , Radiocirugia/mortalidad , Estudios Retrospectivos , Programa de VERF , Análisis de Supervivencia , Texas , Resultado del Tratamiento , Espera VigilanteRESUMEN
Watching another person in pain activates brain areas involved in the sensation of our own pain. Importantly, this neural mirroring is not constant; rather, it is modulated by our beliefs about their intentions, circumstances, and group allegiances. We investigated if the neural empathic response is modulated by minimally-differentiating information (e.g., a simple text label indicating another's religious belief), and if neural activity changes predict ingroups and outgroups across independent paradigms. We found that the empathic response was larger when participants viewed a painful event occurring to a hand labeled with their own religion (ingroup) than to a hand labeled with a different religion (outgroup). Counterintuitively, the magnitude of this bias correlated positively with the magnitude of participants' self-reported empathy. A multivariate classifier, using mean activity in empathy-related brain regions as features, discriminated ingroup from outgroup with 72% accuracy; the classifier's confidence correlated with belief certainty. This classifier generalized successfully to validation experiments in which the ingroup condition was based on an arbitrary group assignment. Empathy networks thus allow for the classification of long-held, newly-modified and arbitrarily-formed ingroups and outgroups. This is the first report of a single machine learning model on neural activation that generalizes to multiple representations of ingroup and outgroup. The current findings may prove useful as an objective diagnostic tool to measure the magnitude of one's group affiliations, and the effectiveness of interventions to reduce ingroup biases.
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Drug development for Alzheimer's disease has endeavored to lower amyloid ß (Aß) by either blocking production or promoting clearance. The benefit of combining these approaches has been examined in mouse models and shown to improve pathological measures of disease over single treatment; however, the impact on cellular and cognitive functions affected by Aß has not been tested. We used a controllable APP transgenic mouse model to test whether combining genetic suppression of Aß production with passive anti-Aß immunization improved functional outcomes over either treatment alone. Compared with behavior before treatment, arresting further Aß production (but not passive immunization) was sufficient to stop further decline in spatial learning, working memory, and associative memory, whereas combination treatment reversed each of these impairments. Cognitive improvement coincided with resolution of neuritic dystrophy, restoration of synaptic density surrounding deposits, and reduction of hyperactive mammalian target of rapamycin signaling. Computational modeling corroborated by in vivo microdialysis pointed to the reduction of soluble/exchangeable Aß as the primary driver of cognitive recovery.
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Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/fisiopatología , Péptidos beta-Amiloides/antagonistas & inhibidores , Cognición , Transducción de Señal , Serina-Treonina Quinasas TOR/metabolismo , Péptidos beta-Amiloides/metabolismo , Animales , Axones/metabolismo , Conducta Animal , Biomarcadores/metabolismo , Quimioterapia Combinada , Inmunización Pasiva , Lisosomas/metabolismo , Ratones Endogámicos C57BL , Ratones Transgénicos , Placa Amiloide/metabolismo , Placa Amiloide/patología , Solubilidad , Sinapsis/metabolismo , TransgenesRESUMEN
Finding objective and quantifiable imaging markers of mild traumatic brain injury (TBI) has proven challenging, especially in the military population. Changes in cortical thickness after injury have been reported in animals and in humans, but it is unclear how these alterations manifest in the chronic phase, and it is difficult to characterize accurately with imaging. We used cortical thickness measures derived from Advanced Normalization Tools (ANTs) to predict a continuous demographic variable: age. We trained four different regression models (linear regression, support vector regression, Gaussian process regression, and random forests) to predict age from healthy control brains from publicly available datasets (n = 762). We then used these models to predict brain age in military Service Members with TBI (n = 92) and military Service Members without TBI (n = 34). Our results show that all four models overpredicted age in Service Members with TBI, and the predicted age difference was significantly greater compared with military controls. These data extend previous civilian findings and show that cortical thickness measures may reveal an association of accelerated changes over time with military TBI.
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Lesiones Traumáticas del Encéfalo/patología , Corteza Cerebral/patología , Imagen por Resonancia Magnética/métodos , Personal Militar/estadística & datos numéricos , Modelos Teóricos , Adulto , Campaña Afgana 2001- , Factores de Edad , Conmoción Encefálica/diagnóstico por imagen , Conmoción Encefálica/epidemiología , Conmoción Encefálica/patología , Lesiones Traumáticas del Encéfalo/diagnóstico por imagen , Lesiones Traumáticas del Encéfalo/epidemiología , Corteza Cerebral/diagnóstico por imagen , Femenino , Humanos , Guerra de Irak 2003-2011 , Masculino , Persona de Mediana Edad , Análisis de Regresión , Estudios Retrospectivos , Adulto JovenAsunto(s)
Linfoma de Células del Manto , Neoplasias Orbitales , Humanos , Linfoma de Células del Manto/diagnóstico por imagen , Linfoma de Células del Manto/patología , Linfoma de Células del Manto/radioterapia , Neoplasias Orbitales/diagnóstico por imagen , Neoplasias Orbitales/patología , Neoplasias Orbitales/radioterapia , Tomografía Computarizada por Rayos XRESUMEN
Functional magnetic resonance imaging (fMRI) is widely used to study brain circuitry in healthy controls and in psychiatry. A major problem of fMRI studies is motion, which affects the quality of images, is a major source of noise, and can confound data if, for example, the experimental groups move differently. Despite continual reminders to experimental subjects about keeping still, however, movement in the scanner remains a problem. The authors hypothesized that showing head movement during a scanning session may help subjects learn how to keep their head still. The authors scanned subjects and displayed in real time a plot of head movement that had three regions. The authors found, in a limited sample, that the improvements were marginal and inconsistent. Thus, they concluded that this strategy, even if likely to work for some people, is probably not sufficiently successful to be implemented at this time.