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1.
BMC Cancer ; 24(1): 171, 2024 Feb 03.
Artículo en Inglés | MEDLINE | ID: mdl-38310262

RESUMEN

BACKGROUND: Radiotherapy delivery regimens can vary between a single fraction (SF) and multiple fractions (MF) given daily for up to several weeks depending on the location of the cancer or metastases. With limited evidence comparing fractionation regimens for oligometastases, there is support to explore toxicity levels to nearby organs at risk as a primary outcome while using SF and MF stereotactic ablative radiotherapy (SABR) as well as explore differences in patient-reported quality of life and experience. METHODS: This study will randomize 598 patients in a 1:1 ratio between the standard arm (MF SABR) and the experimental arm (SF SABR). This trial is designed as two randomized controlled trials within one patient population for resource efficiency. The primary objective of the first randomization is to determine if SF SABR is non-inferior to MF SABR, with respect to healthcare provider (HCP)-reported grade 3-5 adverse events (AEs) that are related to SABR. Primary endpoint is toxicity while secondary endpoints include lesional control rate (LCR), and progression-free survival (PFS). The second randomization (BC Cancer sites only) will allocate participants to either complete quality of life (QoL) questionnaires only; or QoL questionnaires and a symptom-specific survey with symptom-guided HCP intervention. The primary objective of the second randomization is to determine if radiation-related symptom questionnaire-guided HCP intervention results in improved reported QoL as measured by the EuroQoL-5-dimensions-5levels (EQ-5D-5L) instrument. The primary endpoint is patient-reported QoL and secondary endpoints include: persistence/resolution of symptom reporting, QoL, intervention cost effectiveness, resource utilization, and overall survival. DISCUSSION: This study will compare SF and MF SABR in the treatment of oligometastases and oligoprogression to determine if there is non-inferior toxicity for SF SABR in selected participants with 1-5 oligometastatic lesions. This study will also compare patient-reported QoL between participants who receive radiation-related symptom-guided HCP intervention and those who complete questionnaires alone. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT05784428. Date of Registration: 23 March 2023.


Asunto(s)
Neoplasias , Radiocirugia , Humanos , Neoplasias/mortalidad , Neoplasias/patología , Neoplasias/radioterapia , Supervivencia sin Progresión , Calidad de Vida , Radiocirugia/efectos adversos , Radiocirugia/métodos , Estudios de Equivalencia como Asunto
2.
J Appl Clin Med Phys ; 25(5): e14333, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38493500

RESUMEN

PURPOSE: Left ventricle (LV) regional myocardial displacement due to cardiac motion was assessed using cardiovascular magnetic resonance (CMR) cine images to establish region-specific margins for cardiac radioablation treatments. METHODS: CMR breath-hold cine images and LV myocardial tissue contour points were analyzed for 200 subjects, including controls (n = 50) and heart failure (HF) patients with preserved ejection fraction (HFpEF, n = 50), mid-range ejection fraction (HFmrEF, n = 50), and reduced ejection fraction (HFrEF, n = 50). Contour points were divided into segments according to the 17-segment model. For each patient, contour point displacements were determined for the long-axis (all 17 segments) and short-axis (segments 1-12) directions. Mean overall, tangential (longitudinal or circumferential), and normal (radial) displacements were calculated for the 17 segments and for each segment level. RESULTS: The greatest overall motion was observed in the control group-long axis: 4.5 ± 1.2 mm (segment 13 [apical anterior] epicardium) to 13.8 ± 3.0 mm (segment 6 [basal anterolateral] endocardium), short axis: 4.3 ± 0.8 mm (segment 9 [mid inferoseptal] epicardium) to 11.5 ± 2.3 mm (segment 1 [basal anterior] endocardium). HF patients exhibited lesser motion, with the smallest overall displacements observed in the HFrEF group-long axis: 4.3 ± 1.7 mm (segment 13 [apical anterior] epicardium) to 10.6 ± 3.4 mm (segment 6 [basal anterolateral] endocardium), short axis: 3.9 ± 1.3 mm (segment 8 [mid anteroseptal] epicardium) to 7.4 ± 2.8 mm (segment 1 [basal anterior] endocardium). CONCLUSIONS: This analysis provides an estimate of epicardial and endocardial displacement for the 17 segments of the LV for patients with normal and impaired LV function. This reference data can be used to establish treatment planning margin guidelines for cardiac radioablation. Smaller margins may be used for patients with higher degree of impaired heart function, depending on the LV segment.


Asunto(s)
Insuficiencia Cardíaca , Ventrículos Cardíacos , Imagen por Resonancia Cinemagnética , Humanos , Ventrículos Cardíacos/diagnóstico por imagen , Ventrículos Cardíacos/fisiopatología , Masculino , Femenino , Imagen por Resonancia Cinemagnética/métodos , Persona de Mediana Edad , Insuficiencia Cardíaca/fisiopatología , Insuficiencia Cardíaca/diagnóstico por imagen , Anciano , Planificación de la Radioterapia Asistida por Computador/métodos , Radiocirugia/métodos , Estudios de Casos y Controles , Movimiento , Dosificación Radioterapéutica , Procesamiento de Imagen Asistido por Computador/métodos
3.
J Appl Clin Med Phys ; 22(3): 141-149, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33565210

RESUMEN

Despite a great improvement in target volume dose conformality made possible in recent years by modulated therapies, xerostomia remains a common and severe side effect for head-and-neck radiotherapy patients. It is known that parotid glands exhibit a spatially varying dose response; however, the relative importance of subregions throughout the entire gland has yet to be incorporated into treatment plan optimization, with the current standard being to minimize the mean dose to whole parotid glands. The relative importance of regions within contralateral parotid glands has been recently quantified, creating an opportunity for the development of a method for including this data in plan optimization. We present a universal and straightforward approach for imposing varying sub-parotid gland dose constraints during inverse treatment planning by using patient-specific artificial base plans to penalize dose deposited in sensitive regions. In this work, the proposed method of optimization is demonstrated to reduce dose to regions of high relative importance throughout contralateral parotids and improve predictions for stimulated saliva output at 1-year post-radiotherapy. This method may also be applied to impose varying dose constraints to other organs-at-risk for which regional importance data exists.


Asunto(s)
Neoplasias de Cabeza y Cuello , Radioterapia Conformacional , Neoplasias de Cabeza y Cuello/radioterapia , Humanos , Glándula Parótida , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por Computador
4.
Reproduction ; 159(3): 325-337, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-31940276

RESUMEN

The fertility of women declines sharply after age 35 and is essentially lost upon menopause at age 51. The ovary plays an important part in aging-associated changes in women's physiology since it is an essential component of both the reproductive and endocrine systems. Several previous studies in mice have shown that the ovarian tissue goes through drastic changes over the course of aging and exhibits signs of aging-associated chronic inflammation (inflammaging), which may contribute to the marked decline of oocyte quality in aged individuals. To further examine aging-associated gene expression changes in the ovary and to characterize the development of inflammaging, we performed detailed transcriptomic analysis of whole ovaries from mice of six different age groups over the mouse reproductive lifespan and identified more than 5000 genes with significant expression change over the course of aging. Intriguingly, we found aging-associated changes in the expression of several markers that indicate alterations in the composition of ovarian macrophages, which are known to be central players of inflammaging. Using flow cytometry, we analyzed and compared macrophage populations and polarization in young and old ovaries and found a significant increase in monocyte recruitment and macrophage alternative activation (M2) in the old ovaries compared to those in young. Our results are consistent with previous findings of aging-associated increase of fibrosis in the ovarian stromal extracellular matrix, and they provide new clues about the development of inflammaging in the mammalian ovary.


Asunto(s)
Envejecimiento/inmunología , Macrófagos/metabolismo , Ovario/inmunología , Envejecimiento/metabolismo , Animales , Femenino , Regulación de la Expresión Génica , Ratones , Ratones Endogámicos C57BL , Ovario/metabolismo
5.
AJR Am J Roentgenol ; 214(6): 1417-1423, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32208011

RESUMEN

OBJECTIVE. The purpose of this study is to determine whether MRI parameters of placenta accreta spectrum correlate with pathologic and surgical outcomes in high-risk pregnancies. MATERIALS AND METHODS. This retrospective study evaluated second- and third-trimester pregnancies assessed by MRI from 2007 to the present. Women were included in the study if placental invasion was suspected on the basis of a clinical history of cesarean delivery, ultrasound findings, or both. MR images were reviewed by an experienced radiologist who was blinded to the clinical outcomes. Eighteen MRI parameters were assessed and compared with four clinical outcomes: surgical impression of invasion, need for cesarean hysterectomy, pathologic findings, and need for blood transfusion. RESULTS. Of 64 women, 43 required cesarean hysterectomy, 20 underwent cesarean delivery, and one delivered vaginally. There was no statistical difference among the women in terms of maternal age, gestational age, or the number of prior cesarean deliveries. Eight of the 18 MRI parameters assessed showed statistical significance. The five variables with the highest odds ratios were bulge (7.432), placenta previa (7.283), low-attenuation T2 linear bands (5.985), placental heterogeneity near the scar (4.384), and fibrin deposition (4.322), with additional significant variables including interruption of the bladder-serosa interface, the radiologist's interpretation of invasion, and the largest dimension of invasion. Some previously described parameters, such as the degree of maternal pelvic vascularity, were not statistically significant. CONCLUSION. MRI parameters are associated with placental invasion and correlate with the need for cesarean hysterectomy, as well as pathologic and surgical impressions of invasion. From these parameters, an organized template can be created to standardize reporting of placental invasion.


Asunto(s)
Imagen por Resonancia Magnética/métodos , Placenta Accreta/diagnóstico por imagen , Embarazo de Alto Riesgo , Adulto , Cesárea , Femenino , Humanos , Histerectomía , Interpretación de Imagen Asistida por Computador , Embarazo , Resultado del Embarazo , Segundo Trimestre del Embarazo , Tercer Trimestre del Embarazo , Estudios Retrospectivos , Ultrasonografía Prenatal
6.
J Ultrasound Med ; 39(10): 2053-2058, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32342527

RESUMEN

OBJECTIVES: To characterize population-based use of fetal magnetic resonance imaging (MRI) incorporating recent American College of Radiology (ACR)-Society of Perinatal Radiologists (SPR) guidelines about fetal anomalies for which MRI may provide valuable additional information when sonography is limited. METHODS: We conducted a retrospective review of nonreferred singleton pregnancies that received prenatal care and had prenatal sonographic diagnosis of 1 or more major structural anomalies at our hospital between January 2010 and May 2018. Detailed sonography was performed in all anomaly cases. Fetal anomaly information was obtained from a prospectively maintained database, and medical records were reviewed to determine the rationale for why MRI was or was not performed, according to the indication. RESULTS: A total of 104,597 singleton pregnancies underwent sonographic assessments of anatomy at our institution during the study period. Major structural anomalies were identified in 1650 (1.6%) of these pregnancies. Potential indications for fetal MRI per ACR-SPR guidelines were identified in 339 cases. However, fetal MRI was performed in only 253 cases, 15% of those with major anomalies and 75% with a potential indication. Magnetic resonance imaging was not performed in 41 (20%) of identified pregnancies because of an improved prognosis on serial sonography (36), because of a poor prognosis (3), or because it would not alter management (2). CONCLUSIONS: Fetal MRI was used in 15% of those pregnancies with prenatal diagnosis of a major structural anomaly. This amounted to fewer than 0.3% of singleton deliveries. Judicious application of ACR-SPR guidelines in the context of serial sonography results in a relatively small number of fetal MRI examinations in a nonreferred population.


Asunto(s)
Atención Prenatal , Ultrasonografía Prenatal , Femenino , Humanos , Imagen por Resonancia Magnética , Embarazo , Diagnóstico Prenatal , Estudios Retrospectivos
7.
Emerg Radiol ; 26(2): 123-131, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30377859

RESUMEN

PURPOSE: The purpose of this study is to (1) assess the diagnostic yield of ultrasounds performed in the emergency department for suspected breast abscess and determine the rates of reimaging, discordance, and emergent intervention in a large, busy safety net hospital and (2) determine clinical factors significantly associated with abscess as a way to improve patient selection for emergent breast ultrasounds. METHODS: A total of 581 consecutive breast ultrasounds performed in the emergency department for suspected abscess over 15 months were retrospectively reviewed for imaging, demographics, laboratory data, and physical exam findings. Breast abscess was confirmed by combining imaging, clinical, and laboratory data. Linear logistic regression analysis estimated the likelihood of abscess, and the cross-validated area under the receiver operating characteristic curve (AUC) evaluated diagnostic performance. RESULTS: Final diagnoses included abscess (153/581, 26%), cancer (29/581, 5%), granulomatous mastitis (41/581, 7%), normal (120/581, 21%), and other/indeterminate (238/581, 41%). Factors associated with abscess included induration, fluctuance, erythema, drainage, smoking, diabetes, and Black race. Based on these factors, the AUC of the characteristics predictive of abscess was 0.77 (CI, 0.72-0.81). Six breast cancers were not diagnosed on ultrasound. 40% of ultrasounds (231/581) were considered incomplete/inadequate. CONCLUSION: 74% (428/581) of emergent breast ultrasounds in our population were negative for abscess, while 21% (6/29) of cancers were not diagnosed, and 40% (231/581) of exams were incomplete/inadequate. Patient selection for emergent ultrasounds can be improved, allowing patients with a low likelihood of abscess to be imaged in a more optimal setting.


Asunto(s)
Absceso/diagnóstico por imagen , Enfermedades de la Mama/diagnóstico por imagen , Servicio de Urgencia en Hospital/estadística & datos numéricos , Proveedores de Redes de Seguridad , Ultrasonografía Mamaria/estadística & datos numéricos , Absceso/patología , Adulto , Enfermedades de la Mama/patología , Diagnóstico Diferencial , Femenino , Humanos , Persona de Mediana Edad , Estudios Retrospectivos
8.
J Comput Assist Tomogr ; 42(1): 151-154, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-28708727

RESUMEN

We report the imaging findings of a patient with disseminated Mycobacterium avium-intracellulare complex presenting with multiple splenic lesions incompletely characterized on computed tomography in whom magnetic resonance imaging helped narrow the differential diagnosis. We discuss the magnetic resonance imaging findings suggesting the diagnosis, including the presence of focal susceptibility artifact within the lesions (ie, signal drop on T1 in-phase imaging), marked hypointensity on diffusion-weighted imaging, and faint progressive peripheral enhancement after contrast administration. We provide pathologic correlation to explain these imaging characteristics and a review of the literature of imaging characteristics in splenic involvement of M. avium-intracellulare complex infection.


Asunto(s)
Imagen por Resonancia Magnética/métodos , Enfermedades del Bazo/diagnóstico por imagen , Enfermedades del Bazo/microbiología , Antituberculosos/uso terapéutico , Medios de Contraste , Diagnóstico Diferencial , Imagen de Difusión por Resonancia Magnética , Seropositividad para VIH , Humanos , Biopsia Guiada por Imagen , Masculino , Persona de Mediana Edad , Infección por Mycobacterium avium-intracellulare/diagnóstico por imagen
9.
J Magn Reson Imaging ; 44(5): 1312-1319, 2016 11.
Artículo en Inglés | MEDLINE | ID: mdl-27007212

RESUMEN

PURPOSE: To evaluate renal lipid content in subjects with and without type II diabetes mellitus (DM2) using Dixon-based magnetic resonance imaging (MRI). MATERIALS AND METHODS: This retrospective study was approved by the Institutional Review Board and compliant with the Health Insurance Portability and Accountability Act. Sixty-nine adults with or without DM2 (n = 29, n = 40) underwent 3T MRI of the abdomen using 3D multiecho Dixon gradient-echo acquisition and proton-density fat fraction (FF) reconstruction. FF values were recorded within segmented regions of interest in the kidneys and liver. The FF measurement error was estimated from the within-subject difference between the right and left kidneys using Bland-Altman analysis. Correlation between renal FF, hepatic FF, and body mass index (BMI) was evaluated. The association between renal FF and DM2 was evaluated by Wilcoxon rank sum test as well as by multivariate regression to correct for potential confounding effects of age, sex, BMI, creatinine, and hepatic FF. P < 0.05 was considered statistically significant. RESULTS: Per-subject 95% limits of agreement of the renal FF measurement were [-3.26%, +3.22%]. BMI was significantly correlated with renal FF (r = 0.266, P = 0.027) and with liver FF (r = 0.344, P = 0.006). Correlation between renal and hepatic FF did not reach statistical significance (r = 0.215, P = 0.090). Median renal FF (±interquartile range) was 2.18% (±2.52%) in the DM2 cohort, significantly higher than 0.80% (±2.63%) in the non-DM2 cohort (P < 0.001). After correcting for potential confounders, the relationship between DM2 and renal FF remained statistically significant (P = 0.005). CONCLUSION: Renal lipid content can be measured noninvasively using Dixon-based MRI and may be increased in subjects with DM2 compared to those without DM2. J. Magn. Reson. Imaging 2016;44:1312-1319.


Asunto(s)
Diabetes Mellitus Tipo 2/metabolismo , Nefropatías Diabéticas/metabolismo , Interpretación de Imagen Asistida por Computador/métodos , Metabolismo de los Lípidos , Imagen por Resonancia Magnética/métodos , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/diagnóstico por imagen , Nefropatías Diabéticas/diagnóstico por imagen , Nefropatías Diabéticas/etiología , Femenino , Humanos , Aumento de la Imagen/métodos , Masculino , Persona de Mediana Edad , Imagen Molecular/métodos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
10.
Phys Med Biol ; 69(10)2024 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-38604177

RESUMEN

Objective. To improve intravoxel incoherent motion imaging (IVIM) magnetic resonance Imaging quality using a new image denoising technique and model-independent parameterization of the signal versusb-value curve.Approach. IVIM images were acquired for 13 head-and-neck patients prior to radiotherapy. Post-radiotherapy scans were also acquired for five of these patients. Images were denoised prior to parameter fitting using neural blind deconvolution, a method of solving the ill-posed mathematical problem of blind deconvolution using neural networks. The signal decay curve was then quantified in terms of several area under the curve (AUC) parameters. Improvements in image quality were assessed using blind image quality metrics, total variation (TV), and the correlations between parameter changes in parotid glands with radiotherapy dose levels. The validity of blur kernel predictions was assessed by the testing the method's ability to recover artificial 'pseudokernels'. AUC parameters were compared with monoexponential, biexponential, and triexponential model parameters in terms of their correlations with dose, contrast-to-noise (CNR) around parotid glands, and relative importance via principal component analysis.Main results. Image denoising improved blind image quality metrics, smoothed the signal versusb-value curve, and strengthened correlations between IVIM parameters and dose levels. Image TV was reduced and parameter CNRs generally increased following denoising.AUCparameters were more correlated with dose and had higher relative importance than exponential model parameters.Significance. IVIM parameters have high variability in the literature and perfusion-related parameters are difficult to interpret. Describing the signal versusb-value curve with model-independent parameters like theAUCand preprocessing images with denoising techniques could potentially benefit IVIM image parameterization in terms of reproducibility and functional utility.


Asunto(s)
Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Relación Señal-Ruido , Humanos , Imagen por Resonancia Magnética/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Movimiento , Neoplasias de Cabeza y Cuello/diagnóstico por imagen , Neoplasias de Cabeza y Cuello/radioterapia
11.
Biomed Phys Eng Express ; 10(2)2024 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-38271732

RESUMEN

Objective. Xerostomia and radiation-induced salivary gland dysfunction remain a common side effect for head-and-neck radiotherapy patients, and attempts have been made to quantify the heterogeneity of the dose response within parotid glands. Prostate Specific Membrane Antigen (PSMA) ligands have demonstrated high uptake in salivary glands, which has been shown to correlate with gland functionality. Here we compare several models of parotid gland subregional relative importance with PSMA positron emission tomography (PET) uptake. We then develop a predictive model for Clarket al's relative importance estimates using PSMA PET and CT radiomic features, and demonstrate a methodology for predicting patient-specific importance deviations from the population.Approach. Intra-parotid gland uptake was compared with four regional importance models using 30 [18F]DCFPyL PSMA PET images. The correlation of uptake and importance was ascertained when numerous non-overlapping subregions were defined, while a paired t-test was used to compare binary region pairs. A radiomics-based predictive model of population importance was developed using a double cross-validation methodology. A model was then devised for supplementing population-level subregional importance estimates for each patient using patient-specific radiomic features.Main Results. Anticorrelative relationships were found to exist between PSMA PET uptake and four independent models of subregional parotid gland importance from the literature. Kernel Ridge Regression with principal component analysis feature selection performed best over test sets (Mean Absolute Error = 0.08), with gray level co-occurrence matrix (GLCM) features being particularly important. Deblurring PSMA PET images with neural blind deconvolution strengthened correlations and improved model performance.Significance. This study suggests that regions of relatively low PSMA PET uptake in parotid glands may exhibit relatively high dose-sensitivity. We've demonstrated the utility of PSMA PET radiomic features for predicting relative importance within subregions of parotid glands. PSMA PET appears to be a promising quantitative imaging modality for analyzing salivary gland functionality.


Asunto(s)
Glándula Parótida , Tomografía Computarizada por Tomografía de Emisión de Positrones , Humanos , Cabeza , Glándula Parótida/diagnóstico por imagen , Tomografía de Emisión de Positrones
12.
Phys Med ; 121: 103366, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38657425

RESUMEN

The purpose of this investigation is to quantify the spatial heterogeneity of prostate-specific membrane antigen (PSMA) positron emission tomography (PET) uptake within parotid glands. We aim to quantify patterns in well-defined regions to facilitate further investigations. Furthermore, we investigate whether uptake is correlated with computed tomography (CT) texture features. METHODS: Parotid glands from [18F]DCFPyL PSMA PET/CT images of 30 prostate cancer patients were analyzed. Uptake patterns were assessed with various segmentation schemes. Spearman's rank correlation coefficient was calculated between PSMA PET uptake and feature values of a Grey Level Run Length Matrix using a long and short run length emphasis (GLRLML and GLRLMS) in subregions of the parotid gland. RESULTS: PSMA PET uptake was significantly higher (p < 0.001) in lateral/posterior regions of the glands than anterior/medial regions. Maximum uptake was found in the lateral half of parotid glands in 50 out of 60 glands. The difference in SUVmean between parotid halves is greatest when parotids are divided by a plane separating the anterior/medial and posterior/lateral halves symmetrically (out of 120 bisections tested). PSMA PET uptake was significantly correlated with CT GLRLML (p < 0.001), and anti-correlated with CT GLRLMS (p < 0.001). CONCLUSION: Uptake of PSMA PET is heterogeneous within parotid glands, with uptake biased towards lateral/posterior regions. Uptake within parotid glands was strongly correlated with CT texture feature maps.


Asunto(s)
Glutamato Carboxipeptidasa II , Lisina/análogos & derivados , Glándula Parótida , Tomografía Computarizada por Tomografía de Emisión de Positrones , Urea/análogos & derivados , Humanos , Glándula Parótida/diagnóstico por imagen , Glándula Parótida/metabolismo , Glutamato Carboxipeptidasa II/metabolismo , Masculino , Ligandos , Antígenos de Superficie/metabolismo , Neoplasias de la Próstata/diagnóstico por imagen , Neoplasias de la Próstata/metabolismo , Transporte Biológico , Anciano , Persona de Mediana Edad
13.
Phys Med Biol ; 69(8)2024 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-38513292

RESUMEN

Objective. To simultaneously deblur and supersample prostate specific membrane antigen (PSMA) positron emission tomography (PET) images using neural blind deconvolution.Approach. Blind deconvolution is a method of estimating the hypothetical 'deblurred' image along with the blur kernel (related to the point spread function) simultaneously. Traditionalmaximum a posterioriblind deconvolution methods require stringent assumptions and suffer from convergence to a trivial solution. A method of modelling the deblurred image and kernel with independent neural networks, called 'neural blind deconvolution' had demonstrated success for deblurring 2D natural images in 2020. In this work, we adapt neural blind deconvolution to deblur PSMA PET images while simultaneous supersampling to double the original resolution. We compare this methodology with several interpolation methods in terms of resultant blind image quality metrics and test the model's ability to predict accurate kernels by re-running the model after applying artificial 'pseudokernels' to deblurred images. The methodology was tested on a retrospective set of 30 prostate patients as well as phantom images containing spherical lesions of various volumes.Main results. Neural blind deconvolution led to improvements in image quality over other interpolation methods in terms of blind image quality metrics, recovery coefficients, and visual assessment. Predicted kernels were similar between patients, and the model accurately predicted several artificially-applied pseudokernels. Localization of activity in phantom spheres was improved after deblurring, allowing small lesions to be more accurately defined.Significance. The intrinsically low spatial resolution of PSMA PET leads to partial volume effects (PVEs) which negatively impact uptake quantification in small regions. The proposed method can be used to mitigate this issue, and can be straightforwardly adapted for other imaging modalities.


Asunto(s)
Procesamiento de Imagen Asistido por Computador , Tomografía de Emisión de Positrones , Masculino , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Estudios Retrospectivos , Tomografía de Emisión de Positrones/métodos
14.
Radiat Oncol ; 18(1): 77, 2023 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-37158946

RESUMEN

BACKGROUND: This study leverages a large retrospective cohort of head and neck cancer patients in order to develop machine learning models to predict radiation induced hyposalivation from dose-volume histograms of the parotid glands. METHODS: The pre and post-radiotherapy salivary flow rates of 510 head and neck cancer patients were used to fit three predictive models of salivary hypofunction, (1) the Lyman-Kutcher-Burman (LKB) model, (2) a spline-based model, (3) a neural network. A fourth LKB-type model using literature reported parameter values was included for reference. Predictive performance was evaluated using a cut-off dependent AUC analysis. RESULTS: The neural network model dominated the LKB models demonstrating better predictive performance at every cutoff with AUCs ranging from 0.75 to 0.83 depending on the cutoff selected. The spline-based model nearly dominated the LKB models with the fitted LKB model only performing better at the 0.55 cutoff. The AUCs for the spline model ranged from 0.75 to 0.84 depending on the cutoff chosen. The LKB models had the lowest predictive ability with AUCs ranging from 0.70 to 0.80 (fitted) and 0.67 to 0.77 (literature reported). CONCLUSION: Our neural network model showed improved performance over the LKB and alternative machine learning approaches and provided clinically useful predictions of salivary hypofunction without relying on summary measures.


Asunto(s)
Aprendizaje Automático , Redes Neurales de la Computación , Humanos , Estudios Retrospectivos , Área Bajo la Curva , Glándula Parótida
15.
Cureus ; 14(11): e31060, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36475225

RESUMEN

Modern inverse planning radiotherapy techniques allow for organs at risk (OARs) to evade radiation doses that they would have been subjected to with earlier techniques. The extent to which patient outcomes may be improved using these techniques depends on the delineation accuracy of target volumes and OARs on medical images as well as clinical dose constraints applied to regions of interest (ROIs). The recent discovery of bilateral "tubarial" salivary glands, which were found in the nasopharynx using prostate-specific membrane antigen (PSMA) positron emission tomography (PET), raises concerns over how dose to this region might affect patient outcomes. The dose response of the major salivary glands is known to be variable, and it is possible that the dose in tubarial glands constitutes a missing variable in the optimization of head and neck (HN) radiotherapy plans. A necessary first step toward conducting clinical studies that include the tubarial glands in plan optimization is to develop methods for delineating these glands without the use of PSMA PET images, as their acquisition is not considered a part of the standard of care for HN patients. In this study, we develop an open-source program, Organogenesis, for the auto-segmentation of tubarial glands using only computed tomography (CT) images. A predictive model is trained using contours derived from PSMA PET images, allowing for accurate delineation of tubarial glands, which cannot be manually contoured using CT only. Organogenesis provides a predictive model for tubarial glands that can be iteratively improved on with additional data, creating a viable pathway to clinical studies that can assess the importance of incorporating tubarial glands into HN radiotherapy plan optimization.

16.
Phys Med Biol ; 67(12)2022 06 13.
Artículo en Inglés | MEDLINE | ID: mdl-35561699

RESUMEN

Radiomics is an advanced image-processing framework, which extracts image features and considers them as biomarkers towards personalized medicine. Applications include disease detection, diagnosis, prognosis, and therapy response assessment/prediction. As radiation therapy aims for further individualized treatments, radiomics could play a critical role in various steps before, during and after treatment. Elucidation of the concept of radiomics-guided radiation therapy (RGRT) is the aim of this review, attempting to highlight opportunities and challenges underlying the use of radiomics to guide clinicians and physicists towards more effective radiation treatments. This work identifies the value of RGRT in various steps of radiotherapy from patient selection to follow-up, and subsequently provides recommendations to improve future radiotherapy using quantitative imaging features.


Asunto(s)
Procesamiento de Imagen Asistido por Computador , Oncología por Radiación , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Medicina de Precisión/métodos
17.
Personal Disord ; 13(2): 182-191, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-33856836

RESUMEN

The present study examined the associations of positive, negative, and disorganized schizotypy dimensions assessed by the Multidimensional Schizotypy Scale with 5 interview-rated personality disorder diagnoses and traits in 151 young adults. As hypothesized, all 3 schizotypy dimensions were associated with impaired functioning. Positive schizotypy was associated with schizotypal and borderline personality traits; negative schizotypy was associated with schizotypal, schizoid, paranoid, and avoidant personality traits; and disorganized schizotypy was associated with paranoid, borderline, and avoidant personality disorder traits. Negative schizotypy predicted broad diagnoses of Cluster A personality disorders. Both negative and disorganized schizotypy predicted the broad diagnosis of any of the 5 personality disorders. The study further examined the association of the schizotypy dimensions with the individual personality disorder criteria to better understand the overall associations. Given the common origins and high comorbidity, we examined whether the schizotypy dimensions explained the association of borderline and schizotypal personality disorder traits. Positive and disorganized schizotypy fully mediated the association between borderline and schizotypal traits. In summary, the study replicated and extended previous findings that the schizotypy dimensions are uniquely associated with personality disorders and traits, as well as impaired functioning, in young adults. The study also provided additional support for the construct validity of the Multidimensional Schizotypy Scale and for the use of psychometric assessment of schizotypy. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Asunto(s)
Trastorno de Personalidad Limítrofe , Trastorno de la Personalidad Esquizotípica , Trastorno de Personalidad Limítrofe/diagnóstico , Comorbilidad , Humanos , Psicometría , Trastorno de la Personalidad Esquizotípica/diagnóstico , Adulto Joven
18.
Personal Ment Health ; 16(1): 79-89, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34528403

RESUMEN

The assessment of schizotypy and schizophrenia-spectrum psychopathology has historically been adversely impacted by multiple forms of measurement bias, including racial bias. The Multidimensional Schizotypy Scale (MSS) was developed using modern scale construction methods to minimize measurement bias in the assessment of schizotypic traits. However, studies have not examined the validity of the measurement across different racial groups. The present study examined whether the associations of MSS positive, negative, and disorganized schizotypy subscales with interview-assessed ratings of functioning, schizophrenia-spectrum personality traits, and depressive disorders were generally comparable across nonclinically ascertained samples of Black (n = 46), Asian (n = 87), and White (n = 116) young adults. Consistent with previous findings, all three schizotypy subscales were associated with impairment and schizotypal and paranoid traits. Negative schizotypy was associated with schizoid traits, and disorganized schizotypy was associated with depressive disorders. These associations were comparable across the racial groups, supporting the use of the MSS in these groups. Culturally and empirically valid assessments are essential for providing accurate assessments across racial/ethnic groups and reducing the risk of overpathologizing people of color. The present findings support the cross-cultural validity of the MSS; however, future studies should expand upon these findings by including more diverse samples and longitudinal designs.


Asunto(s)
Esquizofrenia , Trastorno de la Personalidad Esquizotípica , Humanos , Psicometría , Psicopatología , Grupos Raciales , Trastorno de la Personalidad Esquizotípica/diagnóstico , Adulto Joven
20.
Reprod Toxicol ; 98: 252-259, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33164761

RESUMEN

Oocytes are vulnerable to alkylating agents like nitrogen mustard (NM), which can cause mitochondrial dysfunction associated with increased oxidative stress. Because mitochondria are maternally inherited, NM exposure affects oocyte mitochondrial physiology and compromises future progeny. Multidrug resistance transporters (MDRs) are transmembrane proteins that efflux such cytotoxic substances; MDR-1 is expressed in oocyte plasma and mitochondrial membranes and protects against oxidative stress. Our objective was to investigate how loss of MDR-1 can modulate oocyte response to NM transgenerationally. Wild Type (WT) and Mdr1a mutant female mice were injected intraperitoneally with sterile saline (control) or 0.1 mg/kg NM. 48 h post-injection, females were either sacrificed for F0 studies or mated with control males to yield F1 pups. After weaning, F1 females were sacrificed or mated to yield F2 pups. Germinal vesicle oocytes were assessed for mitochondrial membrane potential and reactive oxygen species (ROS) levels. NM exposed oocytes of both genotypes exhibited significantly higher ROS than controls in F0 and F1. NM F2 oocytes of neither genotype exhibited significantly higher ROS, though variation in Mdr1a mutants led to an upward trend. NM oocytes of both genotypes exhibited significantly disrupted mitochondrial membrane potential in F0. WT regained normalcy by F1 whereas Mdr1a mutants were unable to by F2. Our data suggest that Mdr1a mutants exhibit transgenerational mitochondrial dysfunction following toxic challenge that persists, implying that MDR-1 protects against toxicant-induced mitochondrial stress. Women without functional MDR-1 exposed to environmental toxicants could therefore be at risk for passing on compromised mitochondria to future offspring.


Asunto(s)
Subfamilia B de Transportador de Casetes de Unión a ATP/genética , Sustancias para la Guerra Química/toxicidad , Mecloretamina/toxicidad , Mitocondrias/efectos de los fármacos , Oocitos/efectos de los fármacos , Efectos Tardíos de la Exposición Prenatal/genética , Animales , Femenino , Mutación con Pérdida de Función , Masculino , Intercambio Materno-Fetal , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Ratones , Mitocondrias/fisiología , Oocitos/metabolismo , Oocitos/fisiología , Embarazo , Efectos Tardíos de la Exposición Prenatal/inducido químicamente , Efectos Tardíos de la Exposición Prenatal/metabolismo , Especies Reactivas de Oxígeno/metabolismo
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