title: High-frequency linear transducer improves detection of an intrauterine pregnancy in first-trimester ultrasonography.
abstract: OBJECTIVE
  The objective was to determine if the need for transvaginal ultrasonographic examination can be decreased by the addition of the transabdominal high-frequency, 12-4-MHz linear transducer after a failed examination with the 6-2-mHz curvilinear transducer when evaluating for an intrauterine pregnancy (IUP).
  
  
  METHODS
  This is a prospective pilot study of women in their first trimester of pregnancy presenting to the emergency department with abdominal pain and/or vaginal bleeding. If no IUP was identified using the curvilinear transducer via the transabdominal approach, they were subsequently scanned using the linear transducer. Patients without evidence of an IUP transabdominally were scanned via the transvaginal approach.
  
  
  RESULTS
  Eighty-one patients were evaluated; no IUP was visualized in 27 using the standard curvilinear transducer approach, and these then had an ultrasonography performed with the linear transducer. Of these, 9 patients (33.3%; 0.95 confidence interval [CO], 15.5%-51.1%) were found to have an IUP with the linear transducer. For the 18 patients who received a transvaginal scan, 15 patients (83.3%; 0.95 CI, 66.1%-100%) had no IUP identified with the transvaginal transducer, and 3 (16.7%; 0.95 CI, 0%-33.9%) had an IUP identified.
  
  
  CONCLUSIONS
  The transabdominal use of a high-frequency linear transducer in the evaluation of patients in the first trimester after failed curvilinear transducer results in a clinically significant reduction in the need for transvaginal ultrasonography to confirm the presence of an IUP.
authors.affiliation: Department of Emergency Medicine, Division of Emergency Ultrasound, MetroHealth Medical Center, Cleveland, OH 44109; Department of Emergency Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106. Electronic address: mtabbut@metrohealth.org.
authors.forename: Matthew
authors.initials: M
authors.lastname: Tabbut
authors.affiliation: Department of Emergency Medicine, Kaiser Permanente, Sacramento Medical Center, Sacramento, CA 95825.
authors.forename: Devin
authors.initials: D
authors.lastname: Harper
authors.affiliation: Department of Emergency Medicine, Division of Emergency Ultrasound, MetroHealth Medical Center, Cleveland, OH 44109.
authors.forename: Diane
authors.initials: D
authors.lastname: Gramer
authors.affiliation: Department of Emergency Medicine, Division of Emergency Ultrasound, MetroHealth Medical Center, Cleveland, OH 44109; Department of Emergency Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106.
authors.forename: Robert
authors.initials: R
authors.lastname: Jones
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D010865:Pilot Projects; D019095:Point-of-Care Systems; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011271:Pregnancy, Ectopic / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D014159:Transducers; D016216:Ultrasonography, Prenatal / Q000295:instrumentation*; D014621:Vagina