Anatomical subgroup analysis of the MERIDIAN cohort: ventriculomegaly.
OBJECTIVE
To assess the contribution of fetal magnetic resonance imaging (MRI) in fetuses of the MERIDIAN cohort diagnosed with ventriculomegaly (VM) as the only abnormal intracranial finding on antenatal ultrasound.


METHODS
This was a subgroup analysis of the MERIDIAN study of fetuses with only VM diagnosed on ultrasound in women who had a subsequent MRI examination within 2 weeks and for whom outcome reference data were available. The diagnostic accuracy of ultrasound and MRI was reported in relation to the severity of VM. The difference in measurements of trigone size on the two imaging methods and the clinical impact of adding MRI to the diagnostic pathway were also studied.


RESULTS
In 306 fetuses with VM, ultrasound failed to detect 31 additional brain abnormalities, having an overall diagnostic accuracy of 89.9% for ultrasound, whilst MRI correctly detected 27 of the additional brain abnormalities, having a diagnostic accuracy of 98.7% (P < 0.0001). There were other brain abnormalities in 14/244 fetuses with mild VM on ultrasound (diagnostic accuracy, 94.3%) and MRI correctly diagnosed 12 of these (diagnostic accuracy, 99.2%; P = 0.0005). There was a close agreement between the size of trigones measured on ultrasound and on MRI, with categorical differences in only 16% of cases, showing that MRI did not systematically overestimate or underestimate trigone size. Complete prognostic data were available in 295/306 fetuses and the prognosis category changed after MRI in 69/295 (23.4%) cases. The overall effect of MRI on clinical management was considered to be 'significant', 'major' or 'decisive' in 76/295 (25.8%) cases.


CONCLUSIONS
Our data suggest that a woman carrying a fetus with VM as the only intracranial finding on ultrasound should be offered an adjuvant investigation by MRI for further evaluation. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.
Academic Unit of Radiology, University of Sheffield and INSIGNEO Institute for in silico Medicine, University of Sheffield, Sheffield, UK.
P D
PD
Griffiths
University Hospital Southampton NHS Foundation Trust, Southampton, UK.
K
K
Brackley
Clinical Trials Research Unit, School of Health and Related Research, University of Sheffield, Sheffield, UK.
M
M
Bradburn
Department of Radiology, Sheffield Children's Hospital and the Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK.
D J A
DJA
Connolly
University Hospital Southampton NHS Foundation Trust, Southampton, UK.
M L
ML
Gawne-Cain
Academic Unit of Radiology, University of Sheffield, Sheffield, UK.
D I
DI
Griffiths
Centre for Women's & Newborn Health, Institute of Metabolism & Systems Research, University of Birmingham and Fetal Medicine Centre, Birmingham Women's Foundation Trust (Birmingham Health Partners), Birmingham, UK.
M D
MD
Kilby
Clinical Trials Research Unit, School of Health and Related Research, University of Sheffield, Sheffield, UK.
L
L
Mandefield
Clinical Trials Research Unit, School of Health and Related Research, University of Sheffield, Sheffield, UK.
C
http://orcid.org/0000-0002-3086-7348
C
Mooney
Newcastle University, Newcastle upon Tyne, UK.
S C
SC
Robson
Clinical and Experimental Sciences University of Southampton and Southampton Children's Hospital, University Hospital Southampton NHS Foundation Trust, Southampton, UK.
B
B
Vollmer
Leeds Teaching Hospitals NHS Trust, Leeds, UK.
G
G
Mason
D000328:Adult; D002552:Cerebral Ventricles / Q000002:abnormalities* / Q000033:anatomy & histology / Q000473:pathology; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000000981:diagnostic imaging* / Q000473:pathology; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D011247:Pregnancy; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016216:Ultrasonography, Prenatal; D006113:United Kingdom
diagnostic accuracy; fetus; magnetic resonance imaging; ultrasonography; ventriculomegaly