Summary of techniques used in the diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH)

TechniqueAdvantagesPotential disadvantages
Ventilation/perfusion (V′/Q′) scanEssential for diagnosing CTEPHCan give intermediate probability result,
Sensitivity >96%which cannot rule out CTEPH
Negative result rules out CTEPHMay underestimate the burden
Can distinguish between large-vessel occlusive and small-vessel pulmonary vascular diseaseof vascular obstruction
Less radiation exposure than CTPA
Less likely than other techniques to detect incidental findings
Avoids potential problems with intravenous contrast
Conventional pulmonary angiography (CPA)Can be combined with RHC to provide imaging and haemodynamic informationInvasive
Right heart catheterisation (RHC)Mandatory in diagnosing CTEPHInvasive
Essential measurements of mean arterial pressure and pulmonary capillary wedge pressure
Information on disease severity, right heart function, mixed venous oxygen saturation
Computed tomography pulmonary angiography (CTPA)NoninvasiveSensitivity 51% (lower than V′/Q′ scan)
High-resolution imagesChronic disease looks different to acute PE:
New scanners can provide multi-planar and three-dimensional reconstructions of the vascular tree More anatomical detail than MRI: information about vascular wall thickness and surrounding structures not appreciable with CPA No need for direct catheter accessadditional training required Risk of false positives (e.g. pulmonary artery sarcoma) May miss disease in distal segmental or subsegmental vessels May miss inoperable patients who could
Can reveal associated findings, e.g. bronchial artery collaterals, mosaic perfusion patternsbegin medical therapy May underestimate clot burden
Lower cost than CPA
Rapid acquisition, even in breathless patients
DECTA has improved the detection of distal CTEPH
Cardiac magnetic resonance imaging (MRI)Noninvasive, no radiation exposureLimited availability, expensive,
Morphological, functional and anatomical assessment of heart and pulmonary circulationtime consuming
Useful for repeat studies, e.g. pre- and post-operative monitoring
Phase-contrast MRI can quantify blood flow and peak velocity in the main pulmonary artery
Contrast-enhanced magnetic resonance angiography has similar sensitivity to CTPA
  • PE: pulmonary embolism; DECTA: dual-energy computed tomography angiography. Information from [14, 17, 18].