title: Preferential location of acute pulmonary thromboembolism induced consolidative opacities: assessment with respiratory gated perfusion SPECT-CT fusion images.
abstract: OBJECTIVE
  Preferential location of acute pulmonary thromboembolism (PTE) induced consolidative opacities (infarction/atelectasis) was determined on respiratory gated perfusion SPECT-CT fusion images.
  
  
  METHODS
  Gated end-inspiratory perfusion SPECT images were obtained in 21 patients with acute PTE and 17 patients with inflammatory diseases, using a triple-headed SPECT system and a respiratory tracking device. Anatomical relationships of consolidative opacities and perfusion defects were assessed on gated SPECT-rest inspiratory CT fusion images. The size and radioactivity of perfusion defects with acute PTE consolidative opacities were compared with those of defects without these opacities. The contribution of fusion images for differential diagnosis of acute PTE induced and inflammatory disease induced lesions was evaluated by receiver operating characteristic (ROC) curve analysis.
  
  
  RESULTS
  Of the total 56 acute PTE induced consolidative opacities, 42 (75%) were located at the peripheral interface between the severely decreased and adjacent relatively preserved perfusion areas within wedge shaped perfusion defects on fusion images. These defects with consolidative opacities were significantly larger and had taken up less radioactivity compared with those in the 86 defects without these lesions (P<0.0001). In contrast, of the 29 inflammatory disease induced opacities, 14 (48.2%) had the matched defects and 13 (44.8%) were located at the proximal portion of defects. These preferential locations of acute PTE induced and inflammation induced lesions were significantly different (P<0.01). In ROC curves, the combined reading of fusion images showed a significantly higher differential diagnostic accuracy compared with the reading of CT and SPECT images alone (P<0.01).
  
  
  CONCLUSIONS
  Acute PTE induced consolidative opacities preferentially occur at the peripheral lung interface between severely decreased and adjacent relatively preserved perfusion areas within relatively large and severely decreased perfusion defects. The fusion images, which provide an accurate assessment of the morphological-perfusion defect relationship could, potentially, provide a differential diagnosis between acute PTE induced and inflammatory disease induced lesions.
authors.affiliation: Department of Radiology, Yamaguchi University School of Medicine, Ube, Yamaguchi, Japan.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Zaki
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Suga
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Kawakami
authors.forename: Tomio
authors.initials: T
authors.lastname: Yamashita
authors.forename: Kensaku
authors.initials: K
authors.lastname: Shimizu
authors.forename: Aska
authors.initials: A
authors.lastname: Seto
authors.forename: Naofumi
authors.initials: N
authors.lastname: Matsunaga
mesh_terms: D000208:Acute Disease; D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007249:Inflammation; D008297:Male; D008875:Middle Aged; D010477:Perfusion; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000473:pathology; D012372:ROC Curve; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals