title: Prevalence of the "double-line" sign when performing focused assessment with sonography in trauma (FAST) examinations.
abstract: The double-line sign (DLS) is a wedge-shaped hypoechoic area in Morison's pouch bounded on both sides by echogenic lines. It represents a false-positive finding for free intraperitoneal fluid when performing focused assessment with sonography in trauma examinations. The purpose of this study was to determine the prevalence of DLS. Secondarily, the study will further investigate the relationship between the presence of a DLS and body mass index (BMI). This was a prospective study that enrolled patients over a 7-month period. Inclusion criteria were patients ≥ 18 years of age presenting to the Emergency Department (ED) requiring a FAST examination as part of the patient's standard medical care. Each examination was performed by one of six experienced ultrasonographers. Presence or absence of the DLS was established in real time and gender, height, weight, and BMI were recorded for each patient. The overall prevalence rate of DLS and the corresponding 95 % confidence interval were calculated, as well as the prevalence rates broken down by BMI characterized as underweight, normal weight, overweight, and obese; and age category (18-29, 30-64, and 65+). The Chi-square test and a Fisher's exact test for BMI category were used to compare the prevalence rates of positive DLS among the different demographic groups. 100 patients were enrolled in the study; the overall prevalence was 27 %. There was no statistical significance among the different demographic groups or BMI. The DLS is a prevalent finding. We believe this sign has become more apparent due to improved imaging technology and resolution.
authors.affiliation: Department of Emergency Medicine, North Shore University Hospital, Manhasset, NY, USA.
authors.forename: Amy Shah
authors.initials: AS
authors.lastname: Patwa
authors.forename: Steven
authors.initials: S
authors.lastname: Cipot
authors.forename: Alvin
authors.initials: A
authors.lastname: Lomibao
authors.forename: Mathew
authors.initials: M
authors.lastname: Nelson
authors.forename: Robert
authors.initials: R
authors.lastname: Bramante
authors.forename: Veena
authors.initials: V
authors.lastname: Modayil
authors.forename: Christine
authors.initials: C
authors.lastname: Haines
authors.forename: Adam
authors.initials: A
authors.lastname: Ash
authors.forename: Christopher
authors.initials: C
authors.lastname: Raio
mesh_terms: D000005:Abdomen / Q000000981:diagnostic imaging*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004636:Emergency Service, Hospital; D005189:False Positive Reactions; D005260:Female; D006470:Hemorrhage / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D014463:Ultrasonography / Q000592:standards; D014947:Wounds and Injuries / Q000175:diagnosis / Q000000981:diagnostic imaging*