False positive lung perfusion/ventilation scan due to rapidly resolved pulmonary abnormalities: Importance of SPECT/CT imaging

Document Type : Case Report


1 Nuclear medicine research center, Mashhad University of Medical Sciences, Mashhad, Iran

2 Department of Nursing and Midwifery, Faculty of Nursing, Gonabad University of Medical Sciences, Gonabad, Iran


An eighty-year-old lady a with history of treated tuberculosis decades ago and polymerase chain reaction (PCR) proven COVID-19 pneumonia about four months ago was referred to our department for ventilation/perfusion scan due to deteriorating dyspnea to rule out P.E. Planar perfusion scan showed bilateral accentuated apical perfusion gradient and multiple segmental and non-segmental perfusion defects in both lungs, which were mismatched with relatively normal planar ventilation images. Perfusion SPECT images also showed multiple segmental, sub-segmental and semi-segmental perfusion defects, which proved to be concordant with consolidations, bilateral pleural effusion, right lung pneumothorax, and atelectasis which were consultant with CT findings. The ventilation SPECT/CT images also demonstrated uniform tracer activity throughout both lungs, with almost complete improvement in consolidations, lung pneumothorax, pleural effusion, and atelectasis. Our case highlights the importance of SPECT/CT imaging in avoiding false-positive interpretation of pulmonary embolism as well as the possibility for rapid resolution of the lung parenchymal abnormalities.


Main Subjects

  1. Roach PJ, Schembri GP, Bailey DL. V/q scanning using SPECT and SPECT/CT. J Nucl Med. 2013 Sep;54(9):1588-96.
  2. Roach PJ, Gradinscak DJ, Schembri GP, Bailey EA, Willowson KP, Bailey DL. SPECT/CT in V/Q scanning. Semin Nucl Med. 2010 Nov;40(6):455-66.
  3. Palmowski K, Oltmanns U, Kreuter M, Mottaghy FM, Palmowski M, Behrendt FF. Diagnosis of pulmonary embolism: conventional ventilation/perfusion SPECT is superior to the combination of perfusion SPECT and nonenhanced CT. Respiration. 2014;88(4):291-7.
  4. Le Gal G, Righini M, Roy PM, Sanchez O, Aujesky D,Bounameaux H, Perrier A. Prediction of pulmonary embolism in the emergency department: the revised Geneva score. Ann Intern Med. 2006 Feb 7;144(3):165-71.
  5. Wells PS, Anderson DR, Rodger M, Ginsberg JS, Kearon C, Gent M, A G Turpie, J Bormanis, J Weitz, M Chamberlain, D Bowie, D Barnes, J Hirsh. Derivation of a simple clinical model to categorize patients probability of pulmonary embolism: increasing the modelsutility with the SimpliRED D-dimer. Thromb Haemost. 2000 Mar;83(3):416-20.
  6. Baile EM, King GG, Müller NL, Y D'Yachkova, E E Coche, P D Paré, J R Mayo. Spiral computed tomography is comparable to angiography for the diagnosis of pulmonary embolism. Am J Respir Crit Care Med. 2000 Mar;161(3 Pt 1):1010-5.
  7. Skarlovnik A, Hrastnik D, Fettich J, Grmek M. Lung scintigraphy in the diagnosis of pulmonary embolism: current methods and interpretation criteria in clinical practice. Radiol Oncol. 2014 Jun;48(2):113–119.
  8. Milà M, Bechini J, Vázquez A, Vallejos V, Tenesa M, Espinal A, Fraile M, Monreal M. Acute pulmonary embolism detection with ventilation/perfusion SPECT combined with full dose CT: What is the best option?. Rev Esp Med Nucl Imagen Mol. 2017 May;36(3):139-45.
  9. Bajc M, Schümichen C, Grüning T, Lindqvist A, Le Roux PY, Alatri A, Bauer RW , Dilic M, Neilly B, Verberne HJ, Delgado Bolton RC, Jonson B. EANM guideline for ventilation/perfusion single-photon emission computed tomography (SPECT) for diagnosis of pulmonary embolism and beyond. Eur J Nucl Med Mol Imaging. 2019 Nov;46(12):2429-2451.