RESUMO
Detection of pulmonary nodules on chest x-rays is an important task for radiologists. Previous studies have shown improved detection rates using gray-scale inversion. The purpose of our study was to compare the efficacy of gray-scale inversion in improving the detection of pulmonary nodules on chest x-rays for radiologists and machine learning models (ML). We created a mixed dataset consisting of 60, 2-view (posteroanterior view - PA and lateral view) chest x-rays with computed tomography confirmed nodule(s) and 62 normal chest x-rays. Twenty percent of the cases were separated for a testing dataset (24 total images). Data augmentation through mirroring and transfer learning was used for the remaining cases (784 total images) for supervised training of 4 ML models (grayscale PA, grayscale lateral, gray-scale inversion PA, and gray-scale inversion lateral) on Google's cloud-based AutoML platform. Three cardiothoracic radiologists analyzed the complete 2-view dataset (n=120) and, for comparison to the ML, the single-view testing subsets (12 images each). Gray-scale inversion (area under the curve (AUC) 0.80, 95% confidence interval (CI) 0.75-0.85) did not improve diagnostic performance for radiologists compared to grayscale (AUC 0.84, 95% CI 0.79-0.88). Gray-scale inversion also did not improve diagnostic performance for the ML. The ML did demonstrate higher sensitivity and negative predictive value for grayscale PA (72.7% and 75.0%), grayscale lateral (63.6% and 66.6%), and gray-scale inversion lateral views (72.7% and 76.9%), comparing favorably to the radiologists (63.9% and 72.3%, 27.8% and 58.3%, 19.5% and 50.5% respectively). In the limited testing dataset, the ML did demonstrate higher sensitivity and negative predictive value for grayscale PA (72.7% and 75.0%), grayscale lateral (63.6% and 66.6%), and gray-scale inversion lateral views (72.7% and 76.9%), comparing favorably to the radiologists (63.9% and 72.3%, 27.8% and 58.3%, 19.5% and 50.5%, respectively). Further investigation of other post-processing algorithms to improve diagnostic performance of ML is warranted.
Assuntos
Nódulos Pulmonares Múltiplos , Radiografia Torácica , Humanos , Raios X , Radiografia Torácica/métodos , Estudos Retrospectivos , Nódulos Pulmonares Múltiplos/diagnóstico por imagem , Redes Neurais de Computação , RadiologistasRESUMO
Aortocaval fistulas following endovascular repair of ruptured abdominal aortic aneurysms (rAAA) are rare. We herein describe repair using an Amplatzer Septal Occluder in a 68-year-old male who presented to the emergency department 6 months after ruptured endovascular aneurysm repair (rEVAR) with right heart failure. With the assistance of diagnostic angiography and intravascular ultrasound, the patient was found to have a 1.2 cm diameter aortocaval fistula and a type-II endoleak. His aortocaval fistula was successfully closed using an Amplatzer septal occluder device after failure of attempted closure with an Amplatzer plug and coiling of the aneurysm sac. His symptoms of heart failure improved, and he was discharged to an acute rehabilitation unit. Follow-up at 3 months demonstrated continued improvement in heart failure symptoms, and a small persistent type II endoleak. Aortocaval fistulae are a potentially fatal complication of rAAA. We discuss the sequelae and treatment strategies of aortocaval fistulas following rEVAR including the use of the Amplatzer Septal Occluder.
Assuntos
Aneurisma da Aorta Abdominal/cirurgia , Ruptura Aórtica/cirurgia , Fístula Arteriovenosa/terapia , Implante de Prótese Vascular/instrumentação , Procedimentos Endovasculares/instrumentação , Dispositivo para Oclusão Septal , Veia Cava Inferior , Idoso , Aneurisma da Aorta Abdominal/complicações , Aneurisma da Aorta Abdominal/diagnóstico por imagem , Ruptura Aórtica/complicações , Ruptura Aórtica/diagnóstico por imagem , Fístula Arteriovenosa/diagnóstico por imagem , Fístula Arteriovenosa/etiologia , Endoleak/etiologia , Insuficiência Cardíaca/etiologia , Humanos , Masculino , Desenho de Prótese , Resultado do Tratamento , Veia Cava Inferior/diagnóstico por imagemRESUMO
In the Americas, the only two cholera epidemics of the past century have occurred in the past 25 years. Lessons from the 1991 Peruvian cholera epidemic can help to focus and refine the response to the current Haitian epidemic. After three years of acute epidemic response, we have an opportunity to refocus on the chronic conditions that make societies vulnerable to cholera. More importantly, even as international attention wanes in the aftermath of the earthquake and acute epidemic, we are faced with a need for continued and coordinated investment in improving Haiti's structural defenses against cholera, in particular access to improved water and sanitation.