title: Jugular lymphatic sacs in first-trimester fetuses with normal nuchal translucency.
abstract: OBJECTIVE
  To assess the ultrasonographic appearance of the jugular lymphatic sacs (JLS) in first-trimester fetuses with a normal nuchal translucency (NT).
  
  
  METHODS
  Seventy-five fetuses with a normal NT thickness (< 95(th) percentile) were examined weekly between 11 and 17 weeks of gestation. After measurement of the NT thickness, the neck region was examined using both transvaginal and transabdominal ultrasonography for the presence of JLS. If present, their dimensions were measured in three directions and the volume was calculated using the formula for a spheroid. Data were analyzed using multilevel analysis.
  
  
  RESULTS
  Seventy-five fetuses were evaluated and a total of 243 ultrasound examinations of the neck region were performed. In 25 (33%) of the 75 fetuses, the JLS could be observed once or more than once. In 19 fetuses JLS were visualized once, in five fetuses twice and in one fetus three times. In total, the JLS were visualized 32 times (n = 15 bilaterally, n = 15 only the left JLS and n = 2 only the right JLS). Relatively greater NT thickness was associated with a higher probability of the presence of JLS, although this was not statistically significant (NT < 1 mm, probability 0.07; NT 1-2 mm, probability 0.15, P = 0.10; NT > 2 mm, probability 0.20, P = 0.08). Gestational age was predictive for the presence of JLS, with the highest probability between 13 and 15 weeks of gestation (P < 0.01). No relationship was found between gestational age and the volumes of the left and right JLS.
  
  
  CONCLUSIONS
  The JLS can be visualized on ultrasound examination in a significant proportion of fetuses with normal NT, most often between 13 and 15 weeks of gestation, and this does not seem to be associated with any abnormality in these fetuses.
authors.affiliation: Department of Obstetrics and Gynecology, VU University Medical Center, Amsterdam, The Netherlands. ym.demooij@vumc.nl
authors.forename: Y M
authors.initials: YM
authors.lastname: de Mooij
authors.forename: M N
authors.initials: MN
authors.lastname: Bekker
authors.forename: M D
authors.initials: MD
authors.lastname: Spreeuwenberg
authors.forename: J M G
authors.initials: JM
authors.lastname: van Vugt
mesh_terms: D000328:Adult; D018568:Crown-Rump Length; D005260:Female; D005865:Gestational Age; D006801:Humans; D007601:Jugular Veins; D008221:Lymphoid Tissue / Q000000981:diagnostic imaging* / Q000196:embryology*; D008423:Maternal Age; D009333:Neck / Q000000981:diagnostic imaging / Q000196:embryology; D048208:Nuchal Translucency Measurement; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011446:Prospective Studies; D018615:Ultrasonography, Doppler, Color / Q000379:methods; D016216:Ultrasonography, Prenatal / Q000379:methods