What is a ventilation-perfusion scan?

Radiological test. A ventilation-perfusion (v/q) scan is a specialized radiological lung test comparing mismatches between any part of your lung that still exchanges oxygen (affected in COPD e.g.) and any part that is not receiving blood flow. This is done through radio-tracers. A mismatch means there is a clot in that part of the lung hindering blood flow. Diseases & surgery of the lung complicate interpretation.
Pulmonary embolism. The v/q scan is a nuclear medicine study that is used to evaluate for possible pulmonary embolism or to evaluate resolution of previously known pulmonary embolism. It involves imaging perfusion of the lungs by the blood and imaging ventilation of the lungs by air. A tiny amount of radiation is put into the blood to allow this, and a tiny amount into the air.

Related Questions

What person needs a lung ventilation/perfusion scan?

Folks with a suspicion for blood clot in the lung. This may be due to spells of breathlessness or chest pain or both. More common if there is blood clots in the leg (phlebitis). Read more...
Pulmonary Embolism. Typically, the person who gets a lung ventilation perfusion scan is being evaluated for possible pulmonary embolism, to help guide medical management. Read more...

Why would a pulmonary ventilation/perfusion scan be performed?

Pulmonary Embolism. The main reason to perform a pulmonary ventilation-perfusion (v-q) scan is to rule out the presence of a pulmonary embolus (commonly a blood clot). There are several forms of pulmonary thrombo-embolism, but the most common situation is one of sudden onset, leading to sob. Chronic thrombo-embolism leads to development of sob over a long period and it can also be diagnosed with a v-q scan. Read more...
Pulmonary Embolism. Typically, the person who gets a lung ventilation perfusion scan is being evaluated for possible pulmonary embolism, to help guide medical management. Read more...

What are the differences between pulmonary perfusion scan and pulmonary ventilation scan?

Lung V-Q scan. Ventilation scanning involves the patient breathing in a radiotracer while perfusion scanning involves injecting the radiotracer through an iv. The procedure is done usually to evaluate the presence of absence of a pulmonary embolism (usually a blood clot) and involves comparing the radiotracer's presence in the alveoli vs. Its presence in the lung circulation. Read more...
Blood vs air. The perfusion scan images blood perfusion of the lungs. The ventilation scan is used to image ventilation by air of the lungs. Generally, both are performed together to see how well lung perfusion (blood) matches lung ventilation (air). Read more...

Dr order pulm. Ventilation/perfusion scan for tachardyia and sob. Have normal chest x-ray, ekg, pulmonary test and blood work. Odds it's an embolism?

See below. Prob not a pulmonary embolism but certainly good thing to rule out. I prefer ct pulmonary angiogram to vent perfusion but it should be adequate. Read more...
Odds don't count. Stastitics are only guidelines and don't apply to individual cases. A lung scan (v/q) is accurate if it is considered high probability or normal. The " gold standard" is computerized angiogram of the chest which is very accurate both to diagnose or exclude pulmonary embolism. Talk to your md. If you have no medical contraindications, i would prefer the ct angiogram. Read more...