610 likes | 1.14k Views
Prenatal Diagnostic Ultrasound in Application of Umbilical Cord. 台北榮總婦產部 陳志堯 洪正修主任指導. 2006 年中華醫用超音波年會. 媽媽的慈繩愛索. What Ultrasound Can Do?. In Diagnosis. Vessel Number: Normal cord has 3 vessels encased in Wharton jelly. (2A1V) Arteries flanking the bladder.
E N D
Prenatal Diagnostic Ultrasound in Application of Umbilical Cord 台北榮總婦產部 陳志堯 洪正修主任指導 2006年中華醫用超音波年會
In Diagnosis • Vessel Number: Normal cord has 3 vessels encased in Wharton jelly. (2A1V) • Arteries flanking the bladder. • Cord Coiled: Arteries coil around vein. • Connections: Abdominal wall & central placenta. (vesa previa, velamentous insertion)
Cord Length (50~60 cm) • Short cord • Akinesia sequence • Trisomy 21 • Body stalk anomalies • Long cord • Hyperactivity • Increased likelihood of true cord knot
Single Umbilical Artery • 3% in 1st trimester, 1~2% 2nd tri., 0.63% newborn. • 70% absent LT UA, 30% RT • Size is larger than 3 vessel cord UA • Less coiled • 15% develop IUGR • Non-isolated SUA: 50% aneuploidy (T18 & 13) • D/D • Fused UAs. • Umbilical vessel thrombosis • Excessive Wharton jelly
Umbilical Cord Cyst (UCC) • Para-axial (60%), axial (40%), mid-UC (39%) • 2% in 1st trimester, 2nd~3rd trimester: aneuploidy (T18 & T13) • Single UCC (75%): good prognosis • Multiple UCC (25%): 2/3 aneuploidy & anomalies. • D/D • Normal yolk sac • UC aneurysm • Resolving UC hematoma (rare) • UC supernumerary vessels (very rare, conjoined twins)
Umbilical Cord Aneurysm (UCA) • UV varix (UV > 9mm) • May associated with persistent Rt umbilical vein • Between abdominal insertion site and inferior liver • May be large • UA aneurysm • May have A-V fistula to UV • Associated with multiple anomalies (T18) • Near placental origin • More rare than UV varix; wall may be calcified
Umbilical Cord Aneurysm (UCA) • Careful research for other anomalies • UV varix may be first manifestation of vein pressure • Monitor impending hydrops • Monitor for anemia • Use color Doppler for checking • D/D • Normal fluid-filled structures • Abdominal cysts (choledochal cyst, meconium pseudocyst, ovarian cyst, urachal cyst) • UC cysts
Vasa Previa • Submembranous fetal vessels cross cervical os • Doppler shows fixed fetal vessels overlying cx os • From succenturiate lobe: most common etiology • Best imagine tool: TVS + color Doppler + PW • D/D • Marginal sinus previa • Cord presentation • Uterine vessel near cervix
Vasa Previa • Pathology: 1 in 3500 deliveries • 60~80% fetal mortality if diagnosis missed. • C/S before onset of labor
Nuchal Cord • One or more complete loops of UC around fetal neck. • Males>females; 29% at 42wks • Single loop 10.6%, double 2.5% • Diagnosis best by: Doppler US and 3D ultrasound • Recommendations~ • Look for vascular compromise (S/D ratio) • Fetal growth and movement, amniotic fluid • D/D • Cord adjacent to neck • Cystic hygroma
Special Topic Cord Index
Under coiling is associates with (umbilical coiling index below the 10th percentile) • fetal death • spontaneous preterm delivery • trisomies • low Apgar score at 5 minutes • velamentous cord insertion • single umbilical artery
There was an inverse relationship between the umbilical coiling index and the birth weight percentile. • Over coiling (umbilical coiling index above the 90th percentile) • asphyxia • umbilical arterial pH < 7.05 • small for gestational age infants • trisomies • single umbilical artery
Under-coiling may give way to kinking and compression, whereas over-coiling may give way to occlusion in cases with cord entanglement. • Early second-trimester low umbilical coiling index predicts small-for-gestational-age fetuses.(J Ultrasound Med 20:1183–1188, 2001)
It appears that umbilical cord coiling modulates noticeably blood flow through the umbilical cord.We speculate that more prominent umbilicalcoiling (higher antenatal UCI values) has a protective effect on blood flow in terms of decreased arterial resistance and higher blood flow velocities, as well as increased venous blood flow.