A non-invasive, quantitative method to demonstrate the early effects of therapy in acute pulmonary embolism

Eur J Nucl Med. 2001 Nov;28(11):1605-9. doi: 10.1007/s002590100613.


The objective of this study was to quantify the changes in pulmonary perfusion due to therapy for pulmonary embolism (PE). To this end, seven consecutive patients (five men, two women; mean age 64+/-10 years) were studied. After basal pulmonary arteriography had demonstrated the presence of massive PE, patients were injected intravenously with 4 mCi of technetium-99m-labelled human albumin microspheres and were treated soon thereafter with a 2-h infusion of either alteplase 100 mg (five patients) or heparin 1,750 IU/h (two patients). Then, a second pulmonary arteriography study was obtained, and soon afterwards a single-photon emission tomographic (SPET) perfusion scan was performed. Immediately thereafter, a second intravenous injection of 4 mCi of 99mTc-labelled microspheres was administered, followed by a second SPET scan. At the end of the study, the perfusion changes due to therapy were quantified by subtraction of the images of the two SPET studies; the reperfused areas could be visualised and the volumes of reperfusion quantified. This study demonstrates the validity of a newly devised, relatively rapid and non-invasive method for quantification of the early effects of therapy on pulmonary perfusion in patients presenting with acute PE.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Female
  • Fibrinolytic Agents / therapeutic use
  • Heparin / therapeutic use
  • Humans
  • Image Processing, Computer-Assisted
  • Male
  • Middle Aged
  • Pulmonary Artery / diagnostic imaging
  • Pulmonary Circulation
  • Pulmonary Embolism / diagnostic imaging*
  • Pulmonary Embolism / drug therapy
  • Radiography
  • Radiopharmaceuticals
  • Technetium Tc 99m Aggregated Albumin
  • Thrombolytic Therapy*
  • Tissue Plasminogen Activator / therapeutic use
  • Tomography, Emission-Computed, Single-Photon


  • Fibrinolytic Agents
  • Radiopharmaceuticals
  • Technetium Tc 99m Aggregated Albumin
  • Heparin
  • Tissue Plasminogen Activator