title: Chronologic echogenicity changes and histologic correlates in experimental blood clots: a serial sonographic study.
abstract: OBJECTIVE
  We performed this study to identify echogenicity changes in clots and their correlations with histologic characteristics over time.
  
  
  METHODS
  B-mode sonography was performed at 2, 6, 24, and 48 hours after clot formation in venous blood from healthy donors. Analysis of echogenicity was performed by grayscale median measurement with normalization. We classified clots into 3 groups: dense, intermediate, and loose according to red blood cell (RBC) density on hematoxylin-eosin staining.
  
  
  RESULTS
  Statistically significant chronologic changes in the grayscale median measurements were shown, with a trough at 6 hours and a peak at 24 hours (mean ± SD: 2 hours, 46.8 ± 4.1; 6 hours, 32.2 ± 13.1; 24 hours, 55.4 ± 9.9; 48 hours, 49.0 ± 13.9; P = .027). The grayscale median value was higher in dense RBC clots and lower in loose RBC clots (dense, 61.0 ± 10.6; intermediate, 49.4 ± 13.1; loose, 34.0 ± 12.1; P < .0353).
  
  
  CONCLUSIONS
  Sonography using the grayscale median showed chronologic echogenicity changes in clots over a 48-hour period, and the grayscale median correlated with RBC density.
authors.affiliation: Zeenat Qureshi Stroke Research Center, University of Minnesota, 420 Delaware St SE, Minneapolis, MN 55455, USA. masakiwatanabe3@gmail.com
authors.forename: Masaki
authors.initials: M
authors.lastname: Watanabe
authors.forename: Shahram
authors.initials: S
authors.lastname: Majidi
authors.forename: Saqib A
authors.initials: SA
authors.lastname: Chaudhry
authors.forename: Adnan I
authors.initials: AI
authors.lastname: Qureshi
mesh_terms: D006801:Humans; D013927:Thrombosis / Q000000981:diagnostic imaging* / Q000473:pathology*; D013997:Time Factors; D014463:Ultrasonography