Letters Pulmonary embolism

V/Q SPECT in the diagnosis of pulmonary embolism

BMJ 2013; 346 doi: http://dx.doi.org/10.1136/bmj.f1555 (Published 19 March 2013) Cite this as: BMJ 2013;346:f1555
  1. Thomas Grüning, consultant in nuclear medicine1,
  2. Brent E Drake, consultant in nuclear medicine and radiology1
  1. 1Derriford Hospital, Plymouth PL6 8DH, UK
  1. thomas.gruning{at}nhs.net

Takach Lapner and Kearon’s review does not reflect current clinical practice with regard to ventilation/perfusion (V/Q) scanning.1 Following publication of European and American specialist society guidelines, two dimensional planar scans are being replaced by three dimensional single photon emission computed tomography (SPECT). V/Q SPECT allows detection of subsegmental pulmonary embolism2 and clearer depiction of some segmental pulmonary embolisms that cannot be visualised on planar scans.3 For the referring clinician, SPECT does away with probability based reporting and simply diagnoses or excludes pulmonary embolism, with few (<5%) non-diagnostic scans. V/Q SPECT was compared with computed tomography pulmonary angiography (CTPA) using at least 16 slice scanners in two small studies that used a composite reference standard (all available imaging, clinical data, follow-up; table).

Results of two studies that compared V/Q SPECT with CTPA in the diagnosis of pulmonary embolism

View this table:

The diagnostic performance of V/Q SPECT for pulmonary embolism was at least as good as that of CTPA. We believe that the choice of imaging for suspected pulmonary embolism should be based on contraindications to exposure to intravenous contrast medium, radiation dose, and local availability of either test.


Cite this as: BMJ 2013;346:f1555