ABSTRACT
BACKGROUND: Head trauma patients may have concomitant facial fractures, which are usually underdetected by head computed tomography alone. This study aimed to identify the clinical indicators of facial fractures and to develop a risk-prediction model to guide the discriminative use of additional facial computed tomography in head trauma. METHODS: The authors retrospectively reviewed head trauma patients undergoing simultaneous head and facial computed tomography at a Level II trauma center from 2015 to 2018. Multivariate logistic regression analysis was used to evaluate independent risk factors for concomitant facial fractures in head trauma patients using data collected from 2015 to 2017, and a risk-prediction model was created accordingly. Model performance was validated with data from 2018. RESULTS: In total, 5045 blunt head trauma patients (development cohort, 3534 patients, 2015 to 2017; validation cohort, 1511 patients, 2018) were enrolled. Concomitant facial fractures occurred in 723 head trauma patients (14.3 percent). Ten clinical and head computed tomographic variables were identified as predictors, including age, male sex, falls from elevation, motorcycle collisions, Glasgow Coma Scale scores less than 14, epistaxis, tooth rupture, facial lesions, intracranial hemorrhage, and skull fracture. In the development cohort, the model showed good discrimination (area under the receiver operating characteristic curve = 0.891), calibration (Hosmer-Lemeshow C test, p = 0.691), and precision (Brier score = 0.066). In the validation cohort, the model demonstrated excellent discrimination (area under the receiver operating characteristic curve = 0.907), good calibration (Hosmer-Lemeshow C test, p = 0.652), and good precision (Brier score = 0.083). With this model, 77.1 percent of unnecessary facial computed tomography could be avoided. CONCLUSION: This model could guide the discriminative use of additional facial computed tomography to detect concomitant facial fractures in blunt head trauma. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.
Subject(s)
Face/diagnostic imaging , Facial Injuries/diagnosis , Head Injuries, Closed/complications , Tomography, X-Ray Computed/statistics & numerical data , Adult , Aged , Aged, 80 and over , Facial Injuries/epidemiology , Facial Injuries/etiology , Female , Glasgow Coma Scale , Head Injuries, Closed/diagnosis , Humans , Injury Severity Score , Logistic Models , Male , Middle Aged , Multivariate Analysis , Prognosis , Retrospective Studies , Risk Assessment/statistics & numerical data , Risk FactorsABSTRACT
BACKGROUND: To evaluate the prevalence and characteristics of paratracheal air cysts and their association with emphysema and gender in a general population using low-dose computed tomography scanning of the chest. MATERIALS AND METHODS: We retrospectively enrolled a total of 924 patients (584 women, 340 men; mean age, 59.73 years; range, 37-89 years) who had received low-dose computed tomography scanning for health examination during the period January 1, 2010 to June 30, 2010. Computed tomographic images were evaluated for the presence of paratracheal air cysts. If paratracheal air cysts were identified, the lungs were reconstructed as a three-dimensional model on a commercial workstation. An emphysema index, an objective quantification of the extent of emphysematous changes on CT imaging, was defined as the percentage area of lung with attenuation values below -950 Hounsfield units. RESULTS: A total of 60 patients with paratracheal air cysts were included in this study (estimated prevalence, 6.5%; 12 men, 48 women; mean age, 59.85; range 45-89 years). Emphysema index differed significantly between genders (P<0.0001). The prevalence of paratracheal air cysts in men was significantly lower than that in women (P=0.005); however, the emphysema index in patients of both genders showed no evidence of emphysema. The majority (95%) of paratracheal air cysts were at the level of the seventh cervical to the second thoracic vertebrae. CONCLUSION: The presence of paratracheal air cysts is a common condition in general populations and should not be misdiagnosed as abnormal paratracheal free air. Paratracheal air cysts are more common in woman than in man. In our study, there is no patient with paratracheal air cysts has CT evidence of emphysema.
Subject(s)
Mediastinal Cyst/diagnostic imaging , Mediastinal Cyst/epidemiology , Mediastinal Emphysema/diagnostic imaging , Mediastinal Emphysema/epidemiology , Radiography, Thoracic/statistics & numerical data , Tomography, X-Ray Computed/statistics & numerical data , Aged , Aged, 80 and over , Comorbidity , Female , Humans , Male , Middle Aged , Prevalence , Taiwan/epidemiologySubject(s)
Arteriovenous Malformations/diagnostic imaging , Lung/blood supply , Pulmonary Artery/abnormalities , Pulmonary Veins/abnormalities , Angiography , Diagnosis, Differential , Humans , Lung/diagnostic imaging , Male , Middle Aged , Pulmonary Artery/diagnostic imaging , Pulmonary Veins/diagnostic imaging , Radiography, Thoracic , Tomography, X-Ray ComputedABSTRACT
A packaging scheme utilizing omni-directional reflective (ODR) optical coating is described to enhance the light extraction of near UV excited, phosphor-converted LEDs. A simple 1D model was developed to analyze the spectra of the extracted light measured with an integration-sphere as a function of phosphor layer concentration and thickness. Quantitative determination of the absorption coefficients at the pump and fluorescent light wavelength along with the conversion coefficient of phosphors were obtained. The reflection of the ODR film and the back reflector are also characterized. These parameters are then used for efficiency optimization of the present packaging scheme. A maximum enhancement of 40% can be expected with the materials and the configuration used in the present work.
