title: Volumetric evaluation of dual-energy perfusion CT for the assessment of intrapulmonary clot burden.
abstract: OBJECTIVE
  To evaluate the volumetric values of intrapulmonary clots (IPCs) using 64-section dual-energy perfusion computed tomography (DEpCT).
  
  
  METHODS
  A total of 174 patients suspected of having acute pulmonary embolism (PE) underwent DEpCT, and acute PE was diagnosed in 48 of these patients. DEpCT images were three-dimensionally reconstructed with four threshold ranges: 1-120 HU (V₁₂₀), 1-15 HU (V₁₅), 1-10 HU (V₁₀), and 1-5 HU (V₅). Each relative value per V₁₂₀ was expressed as %V₁₅, %V₁₀ and %V₅. These values were compared with the d-dimer, pulmonary arterial (PA) pressure, right ventricular (RV) diameter, RV/left ventricular diameter ratio, PA diameter, and CT angiographic obstruction index (CTOI).
  
  
  RESULTS
  In patients with IPCs, PA pressure, d-dimer and volumetric values of DEpCT were significantly higher (p < 0.001). Relative volumetric values at DEpCT had better correlations with the PA pressure, PA diameter, and CTOI than absolute ones, and %V₅ especially had good correlations with PA pressure (r = 0.44, p = 0.02), PA diameter (r = 0.40, p = 0.005), and CTOI (r = 0.38, p = 0.009).
  
  
  CONCLUSIONS
  The relative volumetric evaluation of DEpCT images with a lower attenuation threshold range may be helpful for assessing right heart strain, because these values had good correlation with CTOI, pulmonary pressure, and diameter in suggesting right heart load.
authors.affiliation: Department of Radiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan. Electronic address: radokada@yamaguchi-u.ac.jp.
authors.forename: M
authors.initials: M
authors.lastname: Okada
authors.forename: Y
authors.initials: Y
authors.lastname: Nakashima
authors.forename: Y
authors.initials: Y
authors.lastname: Kunihiro
authors.forename: Y
authors.initials: Y
authors.lastname: Sano
authors.forename: K
authors.initials: K
authors.lastname: Suga
authors.forename: S
authors.initials: S
authors.lastname: Kido
authors.forename: N
authors.initials: N
authors.lastname: Matsunaga
mesh_terms: D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000473:pathology; D011667:Pulmonary Veins / Q000000981:diagnostic imaging / Q000473:pathology; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000379:methods*