A 10yr old boy with a known case of nephrotic syndrome since 4 years on treatment brought to the pediatric OPD with chief complaint of difficulty in breathing. There is no history of fever. On examination, respiratory system was normal except slightly reduced breath sounds on right infra-axillary region. Paediatrician thinks of pleural effusion. What is next best modality of investigation to detect pleural effusion?

USG Is the preferred investigation (imaging modality) to diagnose minimal amount of pleural effusions (yellow dotted arrow) A Ipsilateral Lateral decubitus xray film obtained with the patient lying on their side, effusion side down, can visualise small amounts of fluid layering against the dependent parietal pleura and is preferred x-ray view. Chest radiograph (erect):Both PA and AP erect films are insensitive to small amounts of fluid. Blunting of the costophrenic angle Blunting of the cardiophrenic angle Fluid within the horizontal or oblique fissures