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V/Q Scan: The Preferred and Recommended Screening Test for CTEPH

V/Q scan is the preferred and recommended screening test for chronic thromboembolic disease in patients with PH. CTPA [computed tomography pulmonary angiogram] for screening may lead to potential misdiagnosis of PAH and underdiagnosis of CTEPH, including patients with distal disease.”3

  • The ventilation/perfusion method (V/Q) uses scintigraphy and medical isotopes to evaluate the circulation of air and blood in the lungs.22
  • The ventilation scan detects radioactive gas inhaled by the patient and shows the distribution of ventilation.22
  • The perfusion scan detects radioactive albumin (intravenously injected prior to the scan) and shows the distribution of pulmonary perfusion.22
  • Both scans are usually performed together during a single visit.22
  • As the Fifth World Symposium on PH reported in 2013, V/Q scanning is the preferred screening test for CTEPH because it is far more sensitive than CTPA.3
    • Tunariu et al reported CTPA sensitivity for detecting CTEPH of 51%.23
    • The same authors reported V/Q sensitivity >96%.23
    • A normal V/Q scan can rule out CTEPH.23
    • An abnormal V/Q scan is suggestive of CTEPH—even when a CT scan is negative.23
  • Despite widespread and consistent recommendations that V/Q scanning be used to screen for CTEPH: “Underutilization of V/Q scans in screening PH invites potential misdiagnosis of PAH.”3
  • A positive V/Q scan should be followed by further diagnostic studies consistent with the diagnostic algorithm.18
  • The V/Q scan is also an important diagnostic test for patients with suspected PH or PE patients who are still symptomatic after 3 months of anticoagulation.6

If a V/Q scan suggests CTEPH3, the patient should be referred to a specialized center with expertise in the treatment of this condition.

  • View a video that dispels the myth that computerized tomographic pulmonary angiography has become so sophisticated that it can be used as a screen instead of a V/Q scan to rule out CTEPH.

    Click to Play Video

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An abnormal V/Q scan is suggestive of CTEPH—even when a CT is negative.

V/Q Scanning and RHC in CTEPH


William R. Auger, MD, of UCSD School of Medicine, discusses the use of V/Q scanning and right heart catheterization in diagnosing chronic thromboembolic pulmonary hypertension, or CTEPH.

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