In the 1990s, CT pulmonary angiography emerged as a less invasive alternative to conventional pulmonary angiography and ventilation-perfusion scanning. It used CT with contrast to visualise pulmonary artery clots. It later became a preferred diagnostic test for suspected pulmonary embolism.

CT pulmonary angiography made the hidden clot in the lung visible with startling clarity. For poetry and art, it gives a modern image of breath threatened by an unseen obstruction and restored by knowledge, inspiring poets like Claudia Rankine to explore themes of health, race, and visibility.