title: The rate of resolution of clot burden measured by pulmonary CT angiography in patients with acute pulmonary embolism.
abstract: OBJECTIVE
  The purpose of this article is to quantitatively assess the rate of resolution of clot burden detected on pulmonary CT angiography (CTA) in patients with acute pulmonary embolism (PE).
  
  
  METHODS
  We evaluated 111 consecutive patients (55 men and 56 women) in a retrospective cohort who were diagnosed with PE by pulmonary CTA and had at least one follow-up pulmonary CTA within 1 year. Two radiologists in consensus measured the volume of each clot using a semiautomated quantification program. Semiquantitative measures of clot burden were also computed. The resolution rates of the total clot volume, as well as clot volumes of the central (main and lobar) and peripheral vessels (segmental and subsegmental), were analyzed.
  
  
  RESULTS
  The mean (± SD) clot volume per study was 3403.3 ± 6505.6 mm(3) at baseline and 531.6 ± 2383.5 mm(3) at the follow-up pulmonary CTA. Overall, 85 patients (77% ) showed complete resolution at the follow-up pulmonary CTA. Complete resolution was seen in 17 of 30 patients (56.7%) at a follow-up interval of 1-14 days, in 24 of 31 patients (77.4%) at 29-90 days, and in 32 of 34 patients (94.1%) after 90 days. The total clot volume measurements summed for all patients decreased by 78% (central clot, 69.4%; peripheral clot, 86.0%) at 14 days, by 96.6% (central clot, 93.4%; peripheral clot, 100%) at 90 days, and by 97.7% (central clot, 95.9%; peripheral clot, 100%) after 90 days.
  
  
  CONCLUSIONS
  Clot burden resolved completely in 77% of patients during the follow-up period. Our analysis showed that clots resolved faster in the peripheral arteries than in the central pulmonary arteries.
authors.affiliation: Department of Radiology, University of Pittsburgh Medical Center, 3362 Fifth Ave, Pittsburgh, PA 15213, USA.
authors.forename: Ayaz
authors.initials: A
authors.lastname: Aghayev
authors.forename: Alessandro
authors.initials: A
authors.lastname: Furlan
authors.forename: Amol
authors.initials: A
authors.lastname: Patil
authors.forename: Serter
authors.initials: S
authors.lastname: Gumus
authors.forename: Kyung Nyeo
authors.initials: KN
authors.lastname: Jeon
authors.forename: Bumwoo
authors.initials: B
authors.lastname: Park
authors.forename: Kyongtae T
authors.initials: KT
authors.lastname: Bae
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011651:Pulmonary Artery / Q000000981:diagnostic imaging*; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed