Department of Radiology, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115, USA.
J Ultrasound Med. 2013 Jul;32(7):1207-14. doi: 10.7863/ultra.32.7.1207.
To assess the interobserver agreement, frequency of occurrence, and prognostic importance of the double sac sign (DSS), intradecidual sign (IDS), and other sonographic findings in early intrauterine pregnancies.
We retrospectively identified all sonograms obtained between January 1, 2006, and December 31, 2011, in which: (1) the scan demonstrated an intrauterine fluid collection without a yolk sac or embryo; (2) a follow-up scan confirmed an intrauterine pregnancy; and (3) the first-trimester outcome was known. Each coinvestigator characterized the 199 study sonograms as demonstrating or not demonstrating a DSS or an IDS, based on judgment about whether the scan met published criteria defining these signs.
Interobserver agreement was poor for the DSS (κ= 0.24) and IDS (κ= 0.23). Scans frequently demonstrated neither sign: 150 cases (75.4%) if we considered a sign to be present when both investigators graded it as present and 69 cases (34.7%) using the looser criterion that either graded it as present. The presence of a DSS or an IDS was unrelated to the β-human chorionic gonadotropin (β-hCG) value (P > .05, t test, all comparisons). An inner echogenic ring was present in 158 cases (79.4%), and the decidua was brighter peripherally than centrally in 102 (51.3%). The first-trimester outcome was unrelated to the presence of a DSS or an IDS, presence of an inner echogenic ring, or decidual appearance (P > .05, χ(2), all comparisons).
The sonographic appearance of early gestational sacs, before visualization of a yolk sac or embryo, is highly variable. The DSS and IDS are often absent; there is poor interobserver agreement regarding these signs; and the prognosis is unrelated to their presence or absence. A round or oval intrauterine fluid collection in a woman with positive β-hCG should be treated as a gestational sac until proven otherwise, regardless of whether it demonstrates a DSS or an IDS.
评估双囊征（DSS）、腔内征（IDS）及其他早期宫内妊娠超声表现的观察者间一致性、发生频率及预后意义。
我们回顾性地确定了 2006 年 1 月 1 日至 2011 年 12 月 31 日期间进行的所有超声检查，这些检查符合以下标准：（1）超声显示子宫内有积液，但无卵黄囊或胚胎；（2）后续超声检查证实为宫内妊娠；（3）已知妊娠早期结局。两名研究者根据判断超声是否符合定义这些征象的标准，将 199 例研究超声表现描述为存在或不存在 DSS 或 IDS。
DSS（κ=0.24）和 IDS（κ=0.23）的观察者间一致性较差。如果我们将只有两名研究者都判断为阳性的情况视为阳性，扫描常不显示任何一种征象：150 例（75.4%）；如果采用宽松标准，即只要有一位研究者判断为阳性即可视为阳性，则有 69 例（34.7%）。DSS 或 IDS 的存在与β-人绒毛膜促性腺激素（β-hCG）值无关（P>0.05，t 检验，所有比较）。158 例（79.4%）存在内层回声环，102 例（51.3%）子宫蜕膜呈外周比中央更亮。DSS 或 IDS 的存在、内层回声环的存在或蜕膜外观与妊娠早期结局无关（P>0.05，χ²检验，所有比较）。
在可见卵黄囊或胚胎之前，早期妊娠囊的超声表现高度可变。DSS 和 IDS 常不存在；这些征象的观察者间一致性较差；其存在与否与预后无关。对于β-hCG 阳性的女性，子宫内圆形或椭圆形液体聚集应视为妊娠囊，除非有其他证据，否则应一直如此对待，无论其是否存在 DSS 或 IDS。
