Lung V/Q Scan
What Is a Lung V/Q Scan?
A lung ventilation/perfusion scan, or VQ scan, is a nuclear medicine test that measures airflow
(ventilation) and blood flow (perfusion) in the lungs. Both scans use small amounts of a low-risk
radioactive substance. Ventilation scans involve the inhalation of a small amount of
radioisotope gas. The perfusion scan involves injecting the radioisotopes into a vein in the
patient’s arm. Images are obtained using a specialized camera that will detect the distribution
of the radioactive energy in the body. A VQ scan is most often used to help diagnose or rule out
a serious condition called pulmonary embolism (PE), a sudden blockage in a lung artery caused
by a blood clot. The exam can also detect poor blood flow in the lungs' blood vessels, and it can
provide pictures that help doctors prepare for some types of lung surgery.
CPT Code
78588
Indications
Shortness of breath, chest pain, decreased Oxygen saturation levels, history of COPD, CCF or
asthma.
Contraindications
There are no absolute contraindications.
How Does The Patient Prepare?
The patient may be asked to wear a hospital gown. A chest X-ray will be taken prior to the
exam.
What Happens During the Exam?
Ventilation: The patient will lie on a table that moves under the arm of the scanner, inhaling
through a mask a small amount of radioisotope gas mixed with oxygen. During this process, the
scanner will take pictures that show air going into the lungs. The exam is painless.
Perfusion: For this scan, a small amount of radioisotope is injected into a vein in the arm. The
scanner then takes pictures of blood flow through the lungs. Although the injection itself can be
slightly painful, the exam is otherwise painless.
After the Test
Unless instructed otherwise by the physician or technologist, the patient may resume normal diet and
activities after the exam.
The Results
A radiologist will analyze the images and send a signed report to the referring physician within one
business day.
(Information adapted from www.nhlbi.nih.gov and www.insideradiology.com)
This information is intended for use as merely a guideline for referring physicians and their staff
members only. It contains information pertaining to the most commonly ordered exams and indications.
However, Shawnee Mission Medical Center Radiology does not recommend any particular examination.
Individual radiologist preference or patient circumstances may dictate ordering alternative studies.
Although contrast codes are not needed to place an order, the following contrast codes may be used in
placing orders:
CT Contrast Q9967, MRI contrast A9577 and A9579.