title: Doppler detection of arterio-arterial anastomoses in monochorionic twins: feasibility and clinical application.
abstract: The accuracy of in-vivo detection of arterio-arterial anastomoses (AAA) in monochorionic (MC) twins and its predictive value for twin-twin transfusion syndrome (TTTS) was assessed in 105 consecutive MC twins scanned at fortnightly intervals. AAA were sought using spectral and colour energy Doppler and ultrasound findings were compared with placental injection studies. AAA were identified in vivo in 59 (56%) pregnancies and at injection study in 68 (65%). The overall sensitivity and specificity was 85 and 97.3% respectively for the detection of AAA. Detection rates were higher at later gestations, with anterior placentae and with larger diameter AAA. The median insonation time to detect an AAA was 10 min (range 1-30). Where an AAA was identified, 15% of pregnancies (nine of 59) developed TTTS compared to 61% (28 of 46) when no AAA was seen (odds ratio 8.6). We conclude that AAA can be detected in vivo with high sensitivity and specificity without undue prolongation of scanning times and have a role in risk stratification in the antenatal assessment of MC twins.
authors.affiliation: Centre for Fetal Care, Department of Materno-Fetal Medicine, Imperial College School of Medicine, Queen Charlotte's & Chelsea Hospital, Goldhawk Road, London W6 0XG, UK. myles.taylor@ic.ac.uk
authors.forename: M J
authors.initials: MJ
authors.lastname: Taylor
authors.forename: M L
authors.initials: ML
authors.lastname: Denbow
authors.forename: S
authors.initials: S
authors.lastname: Tanawattanacharoen
authors.forename: C
authors.initials: C
authors.lastname: Gannon
authors.forename: P M
authors.initials: PM
authors.lastname: Cox
authors.forename: N M
authors.initials: NM
authors.lastname: Fisk
mesh_terms: D001159:Arterio-Arterial Fistula / Q000000981:diagnostic imaging* / Q000196:embryology; D015331:Cohort Studies; D005240:Feasibility Studies; D005260:Female; D005315:Fetal Diseases / Q000000981:diagnostic imaging*; D005330:Fetofetal Transfusion / Q000209:etiology; D006801:Humans; D011237:Predictive Value of Tests; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D014430:Twins, Monozygotic; D016216:Ultrasonography, Prenatal