title: Fat embolism syndrome: Do the CT findings correlate with clinical course and severity of symptoms? A clinical-radiological study.
abstract: OBJECTIVE
  Fat embolism syndrome (FES) is rare and diagnosis is challenging. Clinical manifestations are non-specific and no biochemical tests are reliable for diagnosis, highlighting the importance of thoracic CT. Our goal was to describe the CT manifestations of FES and assess whether imaging findings, time of onset of symptoms and time of surgery correlate with clinical course and severity of the disease.
  
  
  METHODS
  Retrospective review of 49 patients with respiratory distress after trauma/intramedullary nail fixation over a 10 year period; 12 patients met clinical criteria and were categorized as non-fulminant (NF-FES) or fulminant FES (F-FES). CT images were analyzed and electronic records reviewed for clinical findings, timeline from trauma to surgery and onset of symptoms. Pearson Chi-square and Levene's test were used and results considered significant when p<0.05.
  
  
  RESULTS
  All patients were men (18-80 years, mean 38 years), 5 (42%) suffered F-FES and 7 (58%) NF-FES. The most common CT finding was ground-glass opacities (8/12, 67%), often with lobular sparing. Consolidation occurred in 4/12 (33%), all in F-FES patients (p=0.004). In 5/5 F-FES, lung involvement was extensive (>75%) whereas most NF-FES had limited involvement (p<0.01). Centrilobular nodules were the predominant finding in 3/12 (16%). Median time between fracture and onset of symptoms was 43h, in 9/12 patients manifesting after surgery. Mean time between trauma and surgery was 20h in NF-FES and 52h in F-FES (p=0.02).
  
  
  CONCLUSIONS
  The most common CT features of FES were ground-glass opacity and consolidation, less commonly, centrilobular nodules. The extent of ground-glass opacities and the presence of consolidation correlated with disease severity. Significant difference was found from time of trauma to surgery in the two groups however is uncertain whether delayed surgery truly increased the risk of F-FES.
authors.affiliation: Department of Radiology, Wesley Hospital, 2 Chasley St., Auchenflower, Brisbane, Queensland 4066, Australia. Electronic address: drnewbigin@gmail.com.
authors.forename: Katrina
authors.initials: K
authors.lastname: Newbigin
authors.affiliation: Department of Medical Imaging, Ottawa Hospital Research Institute, The Ottawa Hospital, University of Ottawa, 501 Smyth Road, Box 232, Ottawa, Ontario K1H8L6, Canada. Electronic address: csouza@toh.on.ca.
authors.forename: Carolina A
authors.initials: CA
authors.lastname: Souza
authors.affiliation: Department of Orthopedic Surgery, Ottawa Hospital Research Institute, The Ottawa Hospital, University of Ottawa, 501 Smyth Road, Box 232, Ottawa, Ontario K1H8L6, Canada. Electronic address: mitarmstrong@toh.on.ca.
authors.forename: Mitchel
authors.initials: M
authors.lastname: Armstrong
authors.affiliation: Department of Medical Imaging, Ottawa Hospital Research Institute, The Ottawa Hospital, University of Ottawa, 501 Smyth Road, Box 232, Ottawa, Ontario K1H8L6, Canada. Electronic address: epena@toh.on.ca.
authors.forename: Elena
authors.initials: E
authors.lastname: Pena
authors.affiliation: Department of Medical Imaging, Ottawa Hospital Research Institute, The Ottawa Hospital, University of Ottawa, 501 Smyth Road, Box 232, Ottawa, Ontario K1H8L6, Canada. Electronic address: jinacio@toh.on.ca.
authors.forename: Joao
authors.initials: J
authors.lastname: Inacio
authors.affiliation: Department of Medical Imaging, Ottawa Hospital Research Institute, The Ottawa Hospital, University of Ottawa, 501 Smyth Road, Box 232, Ottawa, Ontario K1H8L6, Canada. Electronic address: ashgupta@toh.on.ca.
authors.forename: Ashish
authors.initials: A
authors.lastname: Gupta
authors.affiliation: Department of Medical Imaging, Ottawa Hospital Research Institute, The Ottawa Hospital, University of Ottawa, 501 Smyth Road, Box 232, Ottawa, Ontario K1H8L6, Canada. Electronic address: krakhra@toh.on.ca.
authors.forename: Kawan
authors.initials: K
authors.lastname: Rakhra
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D035843:Biomedical Research; D004620:Embolism, Fat / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013577:Syndrome; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
keywords: Computed tomography; Fat embolism; Fat embolism syndrome