ventilation-perfusion scan

scan (skan)

1. to examine or map the body, or one or more organs or regions of it, by gathering information with a sensing device.

2. the data or image so obtained.

3. shortened form of scintiscan.

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A-scan  display on a cathode ray tube of ultrasonic echoes, in which one axis represents the time required for return of the echo and the other corresponds to the strength of the echo.

B-scan  display on a cathode ray tube of ultrasonic echoes, depicting time elapsed and echo strength and producing two-dimensional cross-sectional displays by movement of the transducer.

CAT scan , CT scan computed tomography, or the image obtained from it.

M-mode scan  the image obtained using M-mode echocardiography, showing the motion (M) over time of a monodimensional (“icepick”) section of the heart.

PET scan  positron emission tomography, or the image obtained from it.

ventilation-perfusion scan , V/Q scan a scintigraphic technique for demonstrating perfusion defects in normally ventilated areas of the lung in the diagnosis of pulmonary embolism.

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ventilation-perfusion scan

n.

A diagnostic test for pulmonary embolism in which an x-ray of the lung records the distribution and perfusion of a radionuclide that is inhaled and a second radionuclide that is administered intravenously. Also called V/Q scan.

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ventilation-perfusion scan

Radionuclide scan of lung, V/Q scan Cardiology, Pulmonology A noninvasive radionuclide test that provides functional information as a ratio of pulmonary ventilation–V to blood flow–perfusion, Q through the lungs; in one common protocol, the scan is performed after inhaling 133Xe –20 mCi, 148 MBq and IV injection of 99mTc microacroaggregated albumin, for assessing inspiratory airflow, lung volume, air trapping and adequacy of perfusion; 'indeterminant' studies are not uncommon, and are more frequent in those with underlying lung disease. See Lung volumes, Pulmonary panel.