The V-line: a sonographic aid for the confirmation of pleural fluid.

Background: Ultrasound is being used increasingly to diagnose pathological free fluid accumulation at the bedside. In addition to the detection of peritoneal and pericardial fluid, point-of-care ultrasound allows rapid bedside diagnosis of pleural fluid.

Findings: In this short report, we describe the sonographic observation of the vertebral or 'V-line' to help confirm the presence of pleural fluid in the supine patient. The V-line sign is a result of the fluid acting as an acoustic window to enable visualization of vertebral bodies and posterior thoracic wall, thus confirming the presence of pleural fluid.

Conclusions: The V-line is a useful sonographic sign to aid the diagnosis of pleural free fluid.