title: Factors affecting the lung perfused blood volume in patients with intrapulmonary clots after anti-coagulation therapy.
abstract: OBJECTIVE
  Factors affecting the improvement in the lung perfused blood volume (LPBV) were evaluated based on the presence of intrapulmonary clots (IPCs) after anti-coagulation therapy using 64-slice dual-energy CT.
  
  
  METHODS
  96 patients exhibiting venous thromboembolism underwent initial and repeated LPBV examinations between December 2008 and July 2014. Fifteen patients were excluded due to pulmonary comorbidities, and a total of 81 patients were included in this study. Acute pulmonary embolism (PE) was diagnosed in 46 of the patients (56.7%). LPBV images were three-dimensionally reconstructed with two threshold ranges: 1-120 HU (V120) and 1-5 HU (V5), and the relative value of V5 per V120 expressed as %V5. These values were subsequently compared with indicators of the severity of PE, such as the D-dimer level, heart rate and CT measurements. This study was approved by the local ethics committee.
  
  
  RESULTS
  In patients with IPCs, the D-dimer, V5 and %V5values were significantly larger (p≤0.01) in the initial LPBV, although these differences disappeared in subsequent LPBV after treatment. The right ventricular (RV) diameter, RV/left ventricular (RV/LV) diameter ratio and %V5 values were also significantly reduced, whereas the V5 value did not significantly decrease (p=0.07), but V120 value significantly increased (p<0.001) after treatment. However, in patients with IPCs the change rate in %V5 [(subsequent-initial)/initial %V5] showed a better correlation with that in V5 (r=0.94, p<0.001) rate than that in V120 (r=0.19, p=0.19) after treatment.
  
  
  CONCLUSIONS
  Increased whole lung perfusion (V120) and a decreased low perfusion volume (V5) affect the improvement in the %V5 values after treatment.
authors.affiliation: Department of Radiology, Yamaguchi University Graduate School of Medicine 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan. Electronic address: radokada@yamaguchi-u.ac.jp.
authors.forename: Munemasa
authors.initials: M
authors.lastname: Okada
authors.affiliation: 4th Grade of 6-year Medicine Doctor Program, Department of Medicine, Yamaguchi University Faculty of Medicine and Health Sciences 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Masuda
authors.affiliation: Department of Radiology, Yamaguchi Grand Medical Center, Oosaki 77, Hofu, Yamaguchi 747-8511, Japan.
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Nakashima
authors.affiliation: Department of Radiology, Yamaguchi University Graduate School of Medicine 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Nomura
authors.affiliation: Department of Radiology, Yamaguchi University Graduate School of Medicine 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan.
authors.forename: Sei
authors.initials: S
authors.lastname: Nakao
authors.affiliation: Department of Radiology, St Hills Hospital, Imamurakita 3-7-18, Ube, Yamaguchi 755-0155, Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Suga
authors.affiliation: Computer-aided Diagnosis and Biomedical Imaging Research Biomedical Engineering, Applied Medical Engineering Science Graduate School of Medicine, Yamaguchi University, Tokiwadai 2-16-1, Ube, Yamaguchi 755-8611, Japan.
authors.forename: Shoji
authors.initials: S
authors.lastname: Kido
authors.affiliation: Department of Radiology, Yamaguchi University Graduate School of Medicine 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan.
authors.forename: Naofumi
authors.initials: N
authors.lastname: Matsunaga
mesh_terms: D000925:Anticoagulants / Q000627:therapeutic use*; D001777:Blood Coagulation / Q000187:drug effects* / Q000502:physiology; D001810:Blood Volume / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008168:Lung / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011652:Pulmonary Circulation / Q000187:drug effects / Q000502:physiology; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000503:physiopathology*; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D000925:Anticoagulants
keywords: Anti-coagulation therapy; Computed tomography (CT); Dual energy CT; Intrapulmonary clot burden; Pulmonary embolism