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Recording available 2/16-5/2
Recording available 2/16-5/2
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Abstract Award
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Poster Session 2

Category: Fetal Intervention

Poster Session 2

(576) Beyond ultrasound: MRI for fetal neuroanatomy evaluation following laser surgery for twin-twin transfusion syndrome

Wednesday, February 11, 2026
3:30 PM - 5:00 PM  

    Submitting Author and Presenting Author(s)

  • Manasa G. Rao, MD

    Resident Physician
    Columbia University
    New York, New York, United States

    • Coauthor(s)

  • Lynn L. Simpson, MD (she/her/hers)

    Hillary Rodham Clinton Professor of Women's Health
    Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Columbia University Irving Medical Center
    new york, New York, United States

  • RI

    Rosalie Ingrassia, DNP

    Columbia University Medical Center
    New York, New York, United States

  • NB

    Noelle Breslin, MD

    Northside Hospital
    Atlanta, Georgia, United States

  • CN

    Chia-Ling Nhan-Chang, MD

    Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology and Reproductive Sciences
    San Diego, California, United States

  • RM

    Russell S. Miller, MD (he/him/his)

    Sloane Hospital for Women Associate Professor of Prenatal Pediatrics (in Obstetrics and Gynecology)
    Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Columbia University Irving Medical Center
    New York, New York, United States

Objective:
Fetoscopic laser surgery (FLS) for twin-twin transfusion syndrome (TTTS) appears to reduce neurologic morbidity in surviving monochorionic diamniotic (MCDA) twins. However, abnormal fetal neuroimaging is reported in 2–6% of cases after FLS, and the utility of fetal MRI as an adjunct to ultrasound (US) is unclear. This study aimed to determine the frequency of abnormal fetal MRI findings post-FLS and assess associated perinatal factors.

Study Design:
Retrospective review of MCDA twin pregnancies with TTTS treated with FLS and subsequent fetal MRI at a single center from 2009–24. Univariable and Firth multivariable logistic regression were used to evaluate associations between clinical factors and abnormal MRI findings.

Results:
Fetal MRI was available for 163 of 298 (54.7%) pregnancies. Mean gestational age (GA) at FLS was 19w6d (+/-3d) and at MRI was 22w6d (+/-2d). Twelve patients (7.3%) had abnormal MRIs. Common findings included intraventricular hemorrhage (n=7, 58.3%), ventriculomegaly (n=7, 58.3%), and infarction (n=6, 50%). When correlating with fetal US images, MRI provided additional neurologic findings in 9 (75%) cases. Donor twins had more lesions (11 fetuses, 18 lesions) than recipients (1 fetus, 4 lesions). Neonatal neuroimaging was available for 5 patients. Of those, 3 (60%) had neonatal US/MRI findings correlating to the abnormal fetal MRI. On univariable analysis, factors such as recurrent TTTS, TAPS, pre-MRI PPROM, growth discordance, co-twin demise, BMI, age, and nulliparity were directionally associated with abnormal MRI but not statistically significant. Firth multivariable analysis controlling for age, nulliparity, TTTS stage, co-twin demise and inter-twin discordance found no independent risk factors.

Conclusion:
Abnormal fetal MRI findings occurred in 1 in 13 pregnancies after FLS. Most findings were not obvious on post-FLS surveillance ultrasound. No discrete perinatal risk factors were associated with abnormal MRI. Based on these data, we recommend fetal MRI surveillance for all post-FLS patients.