title: Quantitative lung ultrasound comet measurement: method and initial clinical results.
abstract: OBJECTIVE
  Recently, ultrasound signals termed 'lung water comets' associated with pulmonary edema have been correlated with adverse clinical events in dialysis patients. These comets fluctuate substantially during the ultrasound exam highlighting the need for objective quantitative measurement methods.
  
  
  METHODS
  We developed an image-processing algorithm for the detection and quantification of lung comets. Quantification measures included comet number (comet count) and the fraction of the ultrasound beams with comet findings (comet fraction). We used this algorithm in a pilot study in 20 stable dialysis outpatients to identify associations between ultrasound comets and clinical parameters including blood pressure (BP), percent blood volume reduction on dialysis (%BV), ejection fraction (EF), and ultrafiltration on dialysis (UF).
  
  
  RESULTS
  Positive findings included associations with lung comet measurements with pre-dialysis Diastolic BP (r = 0.534, p = 0.015), subject age (r = -0.446, p = 0.049), and a combination of EF and end dialysis %BV reduction (r = -0.585, p = 0.028). Comet fraction and comet count were closely correlated due to the inherent relationship between these two metrics (r = 0.973, p < 0.001). Negative findings included ultrasound comets that did not change from beginning to end of dialysis (p = 0.756), and were not significantly correlated with single dialysis treatment UF (p = 0.522), subject body weight (p = 0.208), or BMI (p = 0.358).
  
  
  CONCLUSIONS
  Ultrasound signal processing methods may help quantify lung ultrasound comets. Additional findings include algorithmic lung comet measurement that did not change significantly during single dialysis sessions in these stable outpatients, but were associated with cardiovascular and fluid status parameters.
authors: Department of Veterans Affairs Medical Center, University of Michigan, Ann Arbor, Mich. USA.
authors: William F
authors: WF
authors: Weitzel
authors: James
authors: J
authors: Hamilton
authors: Xianglong
authors: X
authors: Wang
authors: Joseph L
authors: JL
authors: Bull
authors: Alan
authors: A
authors: Vollmer
authors: April
authors: A
authors: Bowman
authors: Jonathan
authors: J
authors: Rubin
authors: Grant H
authors: GH
authors: Kruger
authors: Jing
authors: J
authors: Gao
authors: Michael
authors: M
authors: Heung
authors: Panduranga
authors: P
authors: Rao
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001794:Blood Pressure; D001810:Blood Volume; D005260:Female; D006801:Humans; D007668:Kidney / Q000378:metabolism / Q000473:pathology; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011654:Pulmonary Edema / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology; D006435:Renal Dialysis; D051436:Renal Insufficiency, Chronic / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D013318:Stroke Volume; D014462:Ultrafiltration / Q000379:methods; D014463:Ultrasonography; D014883:Water-Electrolyte Imbalance