RESUMEN
Hybrid positron emission tomography-computed tomography (PET-CT) imaging systems are an important tool for assessing the progression of lymphoma. PET-CT systems offer the ability to quantitatively assess lymphocytic bone involvement throughout the body. There is no standard methodology for staging lymphoma patients using PET-CT images. Automatic image segmentation algorithms could offer medical specialists a means to evaluate bone involvement from PET-CT images in a consistent manner. To devise and validate an image segmentation program that may assist staging lymphoma by determining the degree of bone involvement based from PET-CT studies. A custom-made program was developed to segment regions-of-interest from images by utilising an enhanced fuzzy clustering technique that incorporates spatial information. The program was subsequently tested on digital and physical phantoms using four different performance metrics before being employed to extract the bony regions of clinical PET-CT images acquired from 248 patients staged for lymphoma. The algorithm was satisfactorily able to delineate regions-of-interest within all phantoms. When applied to the clinical PET-CT images, the algorithm was capable of accurately segmenting bony regions in less than half of the subjects (n = 103). The performance of the algorithm was adversely affected by the presence of oral contrast, metal implants and the poor image quality afforded by low dose CT images in general. Significant changes are necessary before the algorithm can be employed clinically in an unsupervised fashion. However, with further work performed, the algorithm could potentially prove useful for medical specialists staging lymphoma in the future.
Asunto(s)
Interpretación de Imagen Asistida por Computador , Linfoma/diagnóstico por imagen , Linfoma/patología , Algoritmos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Fantasmas de Imagen , Reproducibilidad de los Resultados , Tomografía Computarizada por Rayos XRESUMEN
High abundance of brown adipose tissue (BAT) is linked to lower glycaemia in humans, leading to the belief that BAT may protect against diabetes. The relationship between BAT glucose utilization and systemic glucose homeostasis has not been defined. In this paper we have characterized glycaemic excursions and BAT thermogenic responses in human brown adipocytes, BAT explants, and healthy adults through supraclavicular temperature profiling, revealing their circadian coupling in vivo and in vitro, orchestrated by UCP1, GLUT4, and Rev-erbα biorhythms. Extent of glycated haemoglobin also correlated positively with environmental temperature among community-dwelling patients. These data uncover potential crosstalk between BAT and glucose regulatory pathways, evident on cellular, tissue, individual, and population levels, and provide impetus to search for BAT harnessing strategies for therapeutic purposes.
Asunto(s)
Tejido Adiposo Pardo/fisiología , Ritmo Circadiano , Glucosa/metabolismo , Termogénesis , Adipocitos Marrones/metabolismo , Adulto , Células Cultivadas , Femenino , Transportador de Glucosa de Tipo 4/metabolismo , Humanos , Masculino , Persona de Mediana Edad , Miembro 1 del Grupo D de la Subfamilia 1 de Receptores Nucleares/metabolismo , Proteína Desacopladora 1/metabolismo , Adulto JovenRESUMEN
Trabecular bone score (TBS) is a measure of gray scale homogeneity that correlates with trabecular microarchitecture and is an independent predictor of fracture risk. TBS is being increasingly used in the assessment of patients at risk of osteoporosis and has recently been incorporated into FRAX®. GE Lunar machines acquire spine scans using 1 of 3 acquisition modes depending on abdominal tissue thickness (thin, standard, and thick). From a database review, 30 patients (mean body mass index: 30.8, range 26.2-34.1) were identified who had undergone lumbar spine DXA scans (GE Lunar Prodigy, software 14.10; Lunar Radiation Corporation, Madison, WI) in both standard mode and thick mode, on the same day with no repositioning. Lumbar spine bone mineral density (L1-L4) and TBS were derived from the 30 paired spine scans. There was no significant difference in lumbar spine bone mineral density between the 2 scanning modes. There were, however, significant higher TBS values from the spine scans acquired in thick mode compared to the TBS values derived from spine acquisitions in standard mode (mean TBS difference: 0.24 [20%], standard deviation ±0.10). In conclusion, these preliminary data suggest that TBS values acquired in the GE Lunar Prodigy are dependent on the scanning mode used. Further evaluation is required to confirm the cause and develop appropriate protocols.
Asunto(s)
Absorciometría de Fotón/métodos , Hueso Esponjoso/diagnóstico por imagen , Vértebras Lumbares/diagnóstico por imagen , Anciano , Algoritmos , Densidad Ósea , Femenino , Humanos , Masculino , Osteoporosis/diagnóstico , Medición de Riesgo/métodosRESUMEN
CONTEXT: Increased bone resorption predicts mortality and bone resorption heightens during critical illness. Bisphosphonates are potent inhibitors of bone resorption. Whether bisphosphonate impacts clinical outcome of intensive care unit (ICU) admission is unknown. OBJECTIVE: We investigated the relationship between preadmission bisphosphonate use and clinical outcome in critically ill patients. DESIGN: This was a retrospective hospital-based analysis. SETTING: The study was conducted at a tertiary referral hospital ICU. PATIENTS: A total of 7830 critically ill patients between 2003 and 2014 participated in the study. INTERVENTIONS: The intervention included bisphosphonate treatment. MAIN OUTCOME MEASURES: In-hospital mortality in the main study (n = 7830) and bone density loss and biochemical and hematological changes in the mechanistic substudy (n = 111) were measured. RESULTS: A total of 245 patients received preadmission bisphosphonate. Bisphosphonate users were older (66 ± 16 vs 58 ± 18 y, P < .01) and had greater comorbid disease burden (Charlson comorbidity index: 5.7 ± 3.6 vs 4.6 ± 3.8, P < .01), yet bisphosphonate use was associated with a lower in-hospital mortality (mortality rate ratio: 0.41, 95% confidence interval 0.24-0.71, P < .01), which remained significant after adjusting for age, sex, principal diagnosis, admitting unit, comorbidities and admission year. Bisphosphonate-associated survival benefit was independent of vitamin D, but bisphosphonate/vitamin D co-use was associated with additive reduction in mortality (mortality rate ratio 0.38, 95% confidence interval 0.20-0.71, P < .01). Bone density decreased during ICU admission (-13% ± 19% per week, P < .01) but was significantly attenuated among bisphosphonate users compared with nonusers (-3% ± 13% per week v. -15% ± 14% per week, P < .01), despite similar disease severity on admission. All bisphosphonate users in the substudy survived, whereas six nonusers died. CONCLUSIONS: Preadmission bisphosphonate use was associated with superior survival among critically ill patients. Prospective studies examining the effects of bisphosphonate in critical illness are required.