Ventilation/perfusion scintigraphy

Ventilation/Perfusion (V/Q) imaging is often very useful in evaluating pati ents in whom a pulmonary embolism (PE) is suspected. A normal scan result c an be used to exclude embolism and a high likelihood ratio scan result can be used to make the diagnosis of PE. Most patients with PE do not have high likelihood ratio scans; therefore, it is important to pursue this diagnosi s in patients with intermediate likelihood ratio scans and in the appropria te clinical setting for patients with the low likelihood ratio scans. In pa tients with parenchymal chest x-ray abnormalities who are likely to fall in to the intermediate category it can be more appropriate to use computed tom ography angiography instead of V/Q scintigraphy.