A comparison grid of nine chest X-ray (CXR) images in the posterior-anterior (PA) or anterior-posterior (AP) view, categorized into 'Normal' and 'COVID' groups for medical educational purposes. The images labeled 'Normal' demonstrate healthy pulmonary anatomy, characterized by clear lung fields, sharp costophrenic angles, and well-defined diaphragmatic borders. In contrast, the 'COVID' images illustrate various stages of COVID-19 pneumonia. Key visible findings in the COVID-positive cases include bilateral and unilateral ground-glass opacities (GGOs), peripheral patchy consolidations, and increased interstitial markings indicating pulmonary inflammation. Some clinical images show advanced pathology with diffuse lung involvement, while others exhibit medical equipment such as electrocardiogram leads or cardiovascular devices. This comparative layout is designed to help students and clinicians distinguish between normal thoracic structures and the characteristic radiologic manifestations of viral pneumonia, specifically focusing on the distribution and density of pulmonary infiltrates.

This diagnostic image shows a posteroanterior (PA) or anteroposterior (AP) chest X-ray (CXR) displayed within a MATLAB graphical user interface titled 'TB-Xpredict'. The radiograph depicts a normal adult thorax. Key anatomical structures include the radiopaque bony framework—specifically the clavicles, ribs, and vertebral column—and the radiolucent lung fields. The cardiac silhouette is visible within the central mediastinum, with clear costophrenic and cardiophrenic angles. The pulmonary vasculature exhibits normal branching patterns without evidence of consolidation, infiltrates, or pleural effusion. The image is labeled 'n17.jpg (Normal)', serving as a baseline reference for computer-aided detection (CAD) systems designed to screen for pulmonary tuberculosis (TB). This content is relevant for medical students and radiology residents focusing on normal thoracic anatomy and the application of machine learning algorithms (such as Gist or PHOG features) in automated diagnostic screening.

A posterior-anterior (PA) view chest X-ray illustrating normal thoracic anatomy. The radiographic image shows clear and well-aerated bilateral lung fields with no visible pulmonary opacities, infiltrates, or masses. The cardiac silhouette is of normal size and position within the mediastinum, and the trachea is observed at the midline. Both costophrenic angles are sharp, and the diaphragmatic domes are clearly defined and appropriately contoured, indicating the absence of pleural effusion. The skeletal structures, including the ribs and clavicles, appear intact without evidence of acute fracture or deformity. This diagnostic image serves as a baseline for a normal chest examination, illustrating healthy pulmonary vasculature radiating from the hilum toward the lung periphery.

This Comparison Chart features two side-by-side posterior-anterior (PA) chest radiographs labeled 'Normal chest X-ray' and 'Abnormal chest X-ray'. The 'Normal' image depicts clear, radiolucent lung fields, sharp costophrenic angles, and a distinct cardiac silhouette. In contrast, the 'Abnormal' image demonstrates a significant focal opacity in the lower-to-middle zone of the right lung, labeled as a 'Mass in the right lung'. This finding represents a radiopaque lesion that obscures the normal pulmonary vascular markings and silhouettes the right heart border. The comparison serves as a diagnostic example for identifying primary lung neoplasms or large pulmonary masses. Key educational concepts include recognizing abnormal densities, understanding radiographic silhouettes, and differentiating healthy pulmonary parenchyma from pathological mass lesions. This material is suitable for undergraduate and intermediate medical education within the fields of radiology, pulmonology, and oncology.