title: MRI phenotypes of localized intravascular coagulopathy in venous malformations.
abstract: BACKGROUND
  The incidence of localized intravascular coagulopathy (LIC) in venous malformations varies with lesion size and location, as well as the presence of palpable phleboliths. The development of LIC can cause pain and hemorrhage and can progress to disseminated intravascular coagulopathy (DIC) and thromboembolic disease resulting in death in some cases. Early recognition of LIC can relieve symptoms and prevent progression to life-threatening complications.
  
  
  OBJECTIVE
  The aim of this work was to identify MRI features of venous malformation associated with LIC. We hypothesized that venous malformations with larger capacitance, slower flow and less physiological compression (greater stasis) were more likely to be associated with LIC.
  
  
  METHODS
  In this HIPAA-compliant and IRB-approved study, we retrospectively reviewed clinical records and MRI for consecutive patients undergoing evaluation of venous malformations at our multidisciplinary Birthmarks and Vascular Anomalies Center between 2003 and 2013. Inclusion required consensus diagnosis of venous malformation and availability of laboratory data and MRI; patients on anticoagulation or those previously undergoing surgical or endovascular treatment were excluded. LIC was diagnosed when D-dimer exceeded 1,000 ng/mL and/or fibrinogen was less than 200 mg/dL. Two board-certified radiologists assessed the following MRI features for each lesion: morphology (spongiform vs. phlebectatic), presence of phleboliths, size, location (truncal vs. extremity), and tissue type(s) involved (subcutis, muscle, bone and viscera). Univariate logistic regression analyses were used to test associations between LIC and MRI findings, and stepwise regression was applied to assess the significance of the individual imaging predictors.
  
  
  RESULTS
  Seventy patients, 37 with LIC, met inclusion criteria during the 10-year study period (age: 14.5 +/- 13.6 years [mean +/- standard deviation]; 30 male, 40 female). Both elevated D-dimer and low fibrinogen were associated with the presence of phleboliths, larger lesion sizes and visceral involvement on MRI (all P < 0.05). In stepwise regressions, lesion size (P < 0.001), the presence of phleboliths (P = 0.005) and lesion morphology (P = 0.006) were all significant predictors of LIC.
  
  
  CONCLUSIONS
  LIC is associated with larger lesion size, visualized phleboliths, truncal location and spongiform morphology on MRI in venous malformations, suggesting that lesions with larger capacitance, slower flow and less physiological compression are more likely to be associated with coagulopathy.
authors.affiliation: Department of Radiology, Boston Children's Hospital, 300 Longwood Ave., Boston, MA, 02115, USA. kevin.koo@childrens.harvard.edu.
authors.forename: Kevin S H
authors.initials: KS
authors.lastname: Koo
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA.
authors.forename: Christopher F
authors.initials: CF
authors.lastname: Dowd
authors.affiliation: Department of Dermatology, University of California, San Francisco, San Francisco, CA, USA.
authors.forename: Erin F
authors.initials: EF
authors.lastname: Mathes
authors.affiliation: Department of Otolaryngology, University of California, San Francisco, San Francisco, CA, USA.
authors.forename: Kristina W
authors.initials: KW
authors.lastname: Rosbe
authors.affiliation: Department of Surgery, University of California, San Francisco, San Francisco, CA, USA.
authors.forename: William Y
authors.initials: WY
authors.lastname: Hoffman
authors.affiliation: Department of Dermatology, University of California, San Francisco, San Francisco, CA, USA.
authors.forename: Ilona J
authors.initials: IJ
authors.lastname: Frieden
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA.
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Hess
mesh_terms: D000293:Adolescent; D000328:Adult; D001778:Blood Coagulation Disorders / Q000209:etiology* / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D054079:Vascular Malformations / Q000150:complications / Q000473:pathology*; D014680:Veins / Q000002:abnormalities* / Q000473:pathology*; D055815:Young Adult
keywords: Adults; Children; Localized intravascular coagulopathy; Magnetic resonance imaging; Morphology; Phleboliths; Venous malformation