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Use of fetal magnetic resonance imaging in patients electing
termination of pregnancy by dilation and evacuation
Geeta Sharma, MD,a Linda Heier, MD,b Robin B. Kalish, MD,a Robert Troiano, MD,c and
Stephen T. Chasen, MDa
New York, NY
OBJECTIVE: The purpose of this study was to determine whether magnetic resonance imaging of the fetal
brain before dilation and evacuation enhances diagnosis when equivocal ultrasound findings and disrupted
autopsy specimens exist.
STUDY DESIGN: Patients with equivocal fetal brain abnormalities on ultrasound examination who were
considering termination of pregnancy were evaluated retrospectively. Abdominal and pelvic magnetic
resonance imaging was performed for further evaluation, and orthogonal fetal brain images were obtained. A
multidisciplinary team reviewed all cases and discussed the findings, possible causes, and recurrence risks
with each patient.
RESULTS: Seven patients with fetal brain anomalies underwent magnetic resonance imaging before dilation
and evacuation. Magnetic resonance imaging diagnoses included intracranial hemorrhages, semilobar
holoprosencephaly, intracranial teratoma, multiple cerebral infarcts, and unilateral cerebellar hypoplasia. In all
cases, magnetic resonance imaging provided valuable information and helped distinguish possible genetic
syndromes from likely sporadic disorders of brain development.
CONCLUSION: Magnetic resonance imaging can provide insight into diagnosis, cause, and recurrence risks
for patients who choose dilation and evacuation because of fetal brain abnormalities. (Am J Obstet Gynecol
2003;189:990-3.)
Key words: Ultrasound examination, magnetic resonance imaging, central nervous system, fetalanomaly
Antenatal ultrasound examination is effective in the
detection of most fetal central nervous system (CNS)
abnormalities.1,2 When ultrasound findings are equivo-
cal, magnetic resonance imaging (MRI) may enhance
the visualization of intracranial structures and lead to
a specific diagnosis. Abnormal fetal CNS findings on MRI
correlate well with pathologic examination3,4 and can
provide clinically relevant information regarding progno-
sis and recurrence risks.
FetalMRI was first described in the 1980s, but its use was
limited by slow capture time that required fetal sedation
with drugs that were administered directly by cord-
ocentesis or to the mother.5 Improved imaging tec-
hniques that were developed in the early 1990s allowed
imaging collection, with acquisition times of 400 msec
From the Departments of Obstetrics and Gynecology, Division ofMaternal-Fetal Medicine,a Neuroradiology,b and Radiology,c WeillMedical College of Cornell University.Presented at the Twenty-third Annual Meeting of the Society for MaternalFetal Medicine, San Francisco, California, February 3-8, 2003.Reprint requests: Geeta Sharma, MD, Department of Obstetrics andGynecology, Division of Maternal-Fetal Medicine, Weill Medical Collegeof Cornell University, 525 E 68th St, Room J-130, New York, NY 10021.E-mail: geeta_sharma@yahoo.com� 2003, Mosby, Inc. All rights reserved.0002-9378/2003 $30.00 + 0doi:10.1067/S0002-9378(03)00712-9
990
that minimized fetal movement artifact. No deleterious
fetal effects have been reported.6
Patients may choose the termination of pregnancy for
fetuses with severe congenital malformations.7,8 Induc-
tion with prostaglandins permits the delivery of an intact
fetus, but completion of the procedure may require up to
3 days.9 In addition, side effects of fever, diarrhea, and
pain are common, although induction protocols that
involve misoprostol and oxytocin (Pitocin) may be better
tolerated.10,11
Alternatively, abortion that is performed between 14 to
24 weeks of gestation can be accomplished by dilation and
evacuation (D&E). This procedure can be performed
safely in experienced hands as an ambulatory procedure.
Some authors have described lower complication rates for
D&E than for other techniques of second trimester
abortion.9,12 For these reasons, patients may choose to
undergo D&E for pregnancy termination.
Although D&E may be preferable from the maternal
standpoint, this procedure often precludes adequate
neuropathologic examination. The purpose of this study
was to determine the contribution of fetal MRI to patient
counseling in cases with severe sonographic fetal brain
abnormalities that were nondiagnostic in patients who
underwent D&E.
Volume 189, Number 4Am J Obstet Gynecol
Sharma et al 991
Table. Comparison of equivocal/nondiagnostic ultrasound findings and MRI results with proposed diagnoses
CaseGestational age (wk)
at ultrasound Ultrasound findingsGestational age(wk) at MRI MRI findings Diagnosis
1 18.4 Ultrasound 1: prominentforehead, small nasalprominence, cavumseptum pellicidum notseen,abnormalventricularconfiguration, smallcerebellum and limbs
18.9 Marked hydrocephalus with in-traventricular hemorrhageseen with blood fluid levels independent portions of ven-tricles; bilateral parasagittalcortical defects, small brain-stem and cerebellum; possi-ble hypoplasia or absence ofcerebellar vermis
Encephaloclastic defectwith acute intracra-nial hemorrhage
18.7 Ultrasound 2: severeventriculomegaly
2 20 Prominent third and lateralventricles, cystic mass inposterior fossa
20.4 Enlarged lateral ventricles,large blood fluid levels seenwithin bilateral occipitalhorns, right frontal horn, andwithin cystic retrovermianmass in the cerebellum
Acute intracranialhemorrhage
3 23.6 Midline intracranial masswith cystic component;mild ventriculomegaly,cavum septum pelluci-dum, thalami and thirdventricle not seen
23.8 Suprasellar mass with centralnecrosis, within third ventri-cle causing obstructive hy-drocephalus; no corpuscollosum visualized
Midline intracranialmass, likely neoplas-tic: teratoma, PNETor glioblastoma
4 17.4 Thin cerebral cortex, dis-ordered and enlargedlateral ventricles, cavumseptum pellicidum notvisualized, and oligohy-dramnios.
17.6 Fused thalami and frontallobes, large supratentorialdorsal cyst, monoventricle
Semilobar holoprosen-cephaly, triploidy
5 19.7 Ventriculomegaly/asym-metry; poorly visualizedmidline structures
19.9 Asymmetric enlargement oflateral ventricles, focal andasymmetric areas of absentcortex; cortical lesions appearto have resulted from vascularinsult; small fourth ventricle
Multiple vascular insultsand aqueductalstenosis
6 18.6 outsideultrasound
Ultrasound 1: Dandy-Walker malformationsuspected, mild hydro-cephalus, corpus collo-sum not visualized
21.6 Corpus collosum and cavumseptum pellicidum visualized,colpocephaly seen; absentmiddle and inferior cerebel-lar vermis and absent midand inferior left cerebellarhemisphere; ex vacuo en-largement of fourth ventricleand cisterna magna; posteriorfossa not enlarged
Primary disorder ofneuronal migration,unilateral cerebellaragenesis
22.6 Ultrasound 2: Dandy-Walker variant suspected
7 21.4 Microcephaly, asymmetriclateral ventricles—colpo-cephaly, cavum septumpellucidum seen, lemonsign
21.9 Right-sided colopocephaly; nosplenium of corpus collosumseen, cavum septum pellici-dum seen, interhemisphericdorsal subarachnoid cystcompressing left occipitalhorn and lobe; small cere-bellar hemispheres
Interhemispheric sub-arachnoid cyst andpartial agenesis ofcorpus collosum
Material and methods
Patients who were included in this study underwent
second-trimester ultrasound examination in our unit
from February 2001 to July 2002. When a severe fetal
CNS anomaly was suspected by ultrasound examination
but a specific diagnosis could not be identified, MRI was
offered for further evaluation. Cytogenetic testing was
also recommended. Patients who were included in this
study were those patients who opted to undergoD&E after
undergoing extensive counseling about the ultrasound
findings. MRI imaging permitted further discussion
regarding possible causes and recurrence risks.
Ultrasound images were obtained with a 6 MHz trans-
abdominal transducer with multihertz and harmonic
capability (Sequoia system 512; Acuson, Mountain View,
Calif). MRI imaging was performed on a 1.5 T General
October 2003Am J Obstet Gynecol
992 Sharma et al
Electric (Milwaukee, Wis) torso coil with multiple echo-
planar T2-weighted sequences. Single-shot fast spin echo
imaging (5-mm thick/0 spacing; field of view, 32; matrix,
256 3 256 with one acquisition) was performed through
the fetal brain in the axial, coronal, and sagittal planes.
Less than 1 week elapsed between our ultrasound and
MRI examinations. Maternal-fetal medicine specialists
reviewed all ultrasound images. MRI images were inter-
preted by a pediatric neuroradiologist and were reviewed
with maternal-fetal medicine specialists. Geneticists were
involved in the multidisciplinary approach, and all pa-
tients were encouraged to undergo genetic counseling.
Results
There were 7 patients who considered termination of
pregnancy because of fetal CNS anomalies that were
suggested by antenatal ultrasound examination. All 7
Fig 1. Case 1: Ultrasound examination and MRI images. A,Acute severe ventriculomegaly that was detected by ultrasoundexamination at 18.7 weeks that was not present at 18.4 weeks. B,MRI visualized a recent hemorrhagic event.
patients chose D&E as the mode for termination of
pregnancy. MRI results in all 7 cases confirmed the
presence of a CNS anomaly, further elucidated possible
diagnoses, and provided information for patient counsel-
ing that was relevant to recurrence risks in subsequent
pregnancies. All pregnancies were conceived spontane-
ously by healthy mothers with no known comorbidities,
consanguinity, or significant genetic histories.
Major ultrasound and MRI findings for the 7 cases are
described in the Table. Figs 1 and 2 show the ultrasound
andMRI images for cases 1 and 3. In all but 1 case (case 6),
the fetal brain was disrupted during evacuation, pre-
cluding neuropathologic examination. In case 6, autopsy
confirmed the MRI findings.
Fig 2. Case 3: Ultrasound examination and MRI images. A, Acircumscribed intracranial mass that was detected by ultrasoundexamination at 23.6 weeks was delineated by (B) MRI as probablyneoplastic.
Volume 189, Number 4Am J Obstet Gynecol
Sharma et al 993
Comment
MRI can be an effective tool to enhance or to confirm
diagnosis when fetal autopsy is not possible. Guo et al3
compared MRI findings to pathologic reports from
neonatal autopsy and induced abortions. Their results
demonstrated a significant correlation between antenatal
MRI and autopsy findings.
Our experience suggests that the use of MRI in patients
who undergo evacuation because of fetal CNS anomalies
can provide valuable information when sonographic
findings are inconclusive. The 2 cases of fetal intracranial
hemorrhage led to testing for alloimmune thrombo-
cytopenia, which commonly recurs and can be treated
aggressively in future pregnancies.13 Although, the testing
revealed no positive results, the small size of the current
series prohibits any conclusions. The preoperative di-
agnosis of fetal holoprosencephaly in 1 case underscored
the importance of cytogenetic testing, the results of which
excluded a syndrome with autosomal recessive inheri-
tance. The diagnoses of intracranial tumor, irregular
cortical clefts, unilateral cerebellar hypoplasia, and in-
terhemispheric subarachnoid cyst suggested sporadic
occurrence, which are unlikely to recur in the future.
Because these MRI diagnoses were made with a high
degree of confidence, we felt that D&E did not prevent
clinically relevant information from being obtained
because of fetal disruption.
In summary, fetal MRI may be indicated in those cases
in which the additional information may offer further
assurance to patients who must come to terms with an
anomalous fetus and the decision of pregnancy termina-
tion. Even in those cases in which the parents are resolved
to pregnancy termination because of sonographic evi-
dence of a severe brain anomaly, MRI may provide
diagnostic findings and reduce the importance of autopsy
in the achievement of a diagnosis.
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