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Intrauterine diagnosis of hydranencephaly by magnetic resonance
,Mognecic Rusonunc~ Printed m the USA.
Imu@g. Vol 7, pp. All right* reserved.
105-107.
1989 Copynghr
0730 725X/89 $3.00 + .I30 @ 19X9 Pergamon Press plc
l Case Report
INTRAUTERINE DIAGNOSIS OF HYDRANENCEPHALY BY MAGNETIC RESONANCE A.
AGUIRRE
VILA-CORO*
AND R.
DOMINGUEZ~
University of Texas Medical School at Houston, *Hermann Eye Center and IDepartment Houston, Texas, USA
of Radiology
Magnetic resonance imaging (MRI) was used to confirm an ultrasound diagnosis of hydranencephaly in utero. MRI provided an accurate anatomical assessment, influencing the pregnancy management. The result supports previous reports suggesting that MRI may be a useful complement to ultrasonography in intrauterine diagnoses. Keywords:
Hydranencephaly;
Magnetic resonance;
Intrauterine; Diagnosis.
INTRODUCTION
Intrauterine diagnoses of severe fetal malformations have increasing management importance. Prenatal diagnosis of hydranencephaly is successfully performed with ultrasonograms.’ However, availability of current magnetic resonance imaging (MRI) techniques allows testing for intrauterine anomalies providing a combination of high contrast resolution imaging and presumed safety for the fetus.2 The purpose of this report is to present a case in which MRI confirmed the antenatal diagnosis of hydranencephaly. To the best of our knowledge, the use of MRI in antenatal evaluation of hydranencephaly has not been reported. CASE
REPORT
Fig. 1. Prenatal axial Tr-weighted magnetic resonance image revealed a fetus in transverse position. The head size is normal. Note the cerebellum, central thalami, and absence of brain mantle.
A 29-year-old Caucasian gravida 2 para 1 was referred to us for evaluation, following ultrasonographic diagnosis of hydranencephaly. Pregnancy history was unremarkable, and personal history was significant only for hypothyroidism treated at age 13 years. Repeated ultrasonogram and MRI confirmed the diagnosis of hydranencephaly. High resolution MRI were obtained by using a 1.5-T GE Signa System. Sagittal, coronal and axial 5 mm slices were obtained, with a 32 cm field of view and an acquisition matrix of 256 x 128. Initial T,-weighted spin-echo images were obtained with a repetition time (TR) of 60 ms and echo time (TE) of 20 ms (Fig. 1). Coronal spin-echo images
were obtained with a multi-slice variable-echo technique with TR = 2,000 ms, TE = 20 and 70 ms, providing spin density (“balanced”) and T2-weighted images (Fig. 2). The fetus was visualized in a transverse position in the upper portion of the uterus, with the head to the mother’s left, face down. The placenta lay along the
RECEIVED6/27/88; ACCEPTED7/16/88. Address correspondence to A. Aguirre Vila-Coro, M.D.,
Hermann Eye Center, 6411 Fannin 77030-1697, USA. 105
Street, Houston,
TX
Magnetic Resonance Imaging 0 Volume 7, Number
106
Fig. 2. Prenatal coronal &weighted magnetic resonance image showed a fetus in a face down position. Note absence of forebrain and presence of central thalami and posterior fossa structures.
posterior aspect of the uterus, extending transversely across the abdomen. The umbilical cord extended anteriorly beneath the anterior margin of the uterus, lying just to the left of the midline. Residual cerebellum and thalami and a portion of the basal ganglia were identified. A thin stripe of brain tissue extended upward in the midline in the region of the falx. A falx was not identified. The cerebral hemispheres were absent. Following psychologic counseling, induction of labor produced a 32-weeks 420 g female. Post-pa&urn evaluation revealed Apgar scores of 8 at one minute and 9 at five minutes, hypothermia, depressed anterior fontanella, inadequate swallowing, mild respiratory distress syndrome, exotropia and pale optic discs. Neonatal brain ultrasound reconfirmed the diagnosis of hydranencephaly (Figs. 3 and 4), showing absence of cerebral hemispheres, presence of midbrain, thalami and cerebellum, and fluid filling of most of the calvarium, with an incomplete septum pellucidurn. Exitus occurred at age one day following several episodes of arterial hypotension and cyanosis. No extraordinary resuscitation attempts were made, and the patient’s heart was donated for transplant. Autopsy permission was not granted.
1, 1989
Fig. 3. Postnatal ultrasound study of the head in a coronal plane. Note the thalami and complete absence of the forebrain.
Fig. 4. Postnatal ultrasound study of the head in an axial plane through the temporal squama. Note the cerebellum and thalami surrounding by massive cerebrospinal fluid.
DISCUSSION We report a case of hydranencephaly with ultrasonographic prenatal diagnosis, confirmed by MRI. Uitrasonography is a convenient, inexpensive and
high resolution diagnostic tool widely used in prenatal diagnosis of fetal abnormalities.’ An alternative imaging technique seems necessary for cases of sonographically questionable fetal maldevelopment or when
Diagnosis of hydranencephaly
by MR 0 A.
a precise diagnosis is not made. Ultrasonographical recognition of a large intracranial fluid collection, for instance, may not suffice to differentiate between a large arachnoid cyst and an alobar holoprosencephaly. Differentiation between those two conditions through other imaging techniques, could result in radically different managements. Compared to ultrasonograms, current MRI techniques have less spatial resolution, lack real-time imaging capabilities, are costly and less versatile. MRI, however, provides a large diagnostic window allowing total fetal imaging with excellent resolution of tissue composition. MRI provides excellent visualization of a precise anatomical plane, allows easy interpretation of images of several planes, and permits computer-assisted reconstruction of multiple planes following one single study. Being more sophisticated than ultrasonography, MRI seems ideal for complex malformations. When compared to computerized tomography (CT) roentgenograms, MRI allows better resolution of some intracranial anomalies, permits direct imaging in multiple planes, does not use ionizing radiation and is less teratogenic.3 This case supports previous reports suggesting that,
ACUIRRE VILA-CORO AND R. DOMINICUEZ
107
although ultrasonography may remain as the primary intrauterine imaging method, MRI may become the ideal non-invasive complementary technique for selected cases.3-5 REFERENCES 1. Pilu, G.; Rizzo, N.; Orsini, L.F.; Bovicelli, L. Antenatal recognition of cerebral anomalies. Ultrasound Med. Biol. 12:319-326; 1986. 2. National Radiological Protection Board. Revised guidance on acceptable limits of exposure during nuclear magnetic clinical imaging. Brit. J. Radiof. 56:974-977;
1983.
3. McCarthy, S.M.; Filly, R.A.; Stark, D.D.; Callen, P.W.; Golbus, M.S.; Hrizak, H. Magnetic resonance imaging of fetal anomalies in utero: early experience. AJR 145: 677-682; 1985. 4, Stark, D.S.; McCarthy, S.M.; Filly, R.A.; Callen, P.W.; Hricak, H.; Parer, J.T. Intrauterine growth retardation: evaluation by magnetic resonance. Radiology 155:425427; 1985. 5. Turner, R.J.; Hankins, G.D.V.; Weinreb, J.C.; Ziaya, P.R.; Davis, T.N.; Lowe, T.W.; Gilstrap, III L.C. Magnetic resonance imaging and ultrasonography in the antenatal evaluation of conjoined twins. Am. J. Obstet.
Gynecol. 155:645-649; 1986.
Imu@g. Vol 7, pp. All right* reserved.
105-107.
1989 Copynghr
0730 725X/89 $3.00 + .I30 @ 19X9 Pergamon Press plc
l Case Report
INTRAUTERINE DIAGNOSIS OF HYDRANENCEPHALY BY MAGNETIC RESONANCE A.
AGUIRRE
VILA-CORO*
AND R.
DOMINGUEZ~
University of Texas Medical School at Houston, *Hermann Eye Center and IDepartment Houston, Texas, USA
of Radiology
Magnetic resonance imaging (MRI) was used to confirm an ultrasound diagnosis of hydranencephaly in utero. MRI provided an accurate anatomical assessment, influencing the pregnancy management. The result supports previous reports suggesting that MRI may be a useful complement to ultrasonography in intrauterine diagnoses. Keywords:
Hydranencephaly;
Magnetic resonance;
Intrauterine; Diagnosis.
INTRODUCTION
Intrauterine diagnoses of severe fetal malformations have increasing management importance. Prenatal diagnosis of hydranencephaly is successfully performed with ultrasonograms.’ However, availability of current magnetic resonance imaging (MRI) techniques allows testing for intrauterine anomalies providing a combination of high contrast resolution imaging and presumed safety for the fetus.2 The purpose of this report is to present a case in which MRI confirmed the antenatal diagnosis of hydranencephaly. To the best of our knowledge, the use of MRI in antenatal evaluation of hydranencephaly has not been reported. CASE
REPORT
Fig. 1. Prenatal axial Tr-weighted magnetic resonance image revealed a fetus in transverse position. The head size is normal. Note the cerebellum, central thalami, and absence of brain mantle.
A 29-year-old Caucasian gravida 2 para 1 was referred to us for evaluation, following ultrasonographic diagnosis of hydranencephaly. Pregnancy history was unremarkable, and personal history was significant only for hypothyroidism treated at age 13 years. Repeated ultrasonogram and MRI confirmed the diagnosis of hydranencephaly. High resolution MRI were obtained by using a 1.5-T GE Signa System. Sagittal, coronal and axial 5 mm slices were obtained, with a 32 cm field of view and an acquisition matrix of 256 x 128. Initial T,-weighted spin-echo images were obtained with a repetition time (TR) of 60 ms and echo time (TE) of 20 ms (Fig. 1). Coronal spin-echo images
were obtained with a multi-slice variable-echo technique with TR = 2,000 ms, TE = 20 and 70 ms, providing spin density (“balanced”) and T2-weighted images (Fig. 2). The fetus was visualized in a transverse position in the upper portion of the uterus, with the head to the mother’s left, face down. The placenta lay along the
RECEIVED6/27/88; ACCEPTED7/16/88. Address correspondence to A. Aguirre Vila-Coro, M.D.,
Hermann Eye Center, 6411 Fannin 77030-1697, USA. 105
Street, Houston,
TX
Magnetic Resonance Imaging 0 Volume 7, Number
106
Fig. 2. Prenatal coronal &weighted magnetic resonance image showed a fetus in a face down position. Note absence of forebrain and presence of central thalami and posterior fossa structures.
posterior aspect of the uterus, extending transversely across the abdomen. The umbilical cord extended anteriorly beneath the anterior margin of the uterus, lying just to the left of the midline. Residual cerebellum and thalami and a portion of the basal ganglia were identified. A thin stripe of brain tissue extended upward in the midline in the region of the falx. A falx was not identified. The cerebral hemispheres were absent. Following psychologic counseling, induction of labor produced a 32-weeks 420 g female. Post-pa&urn evaluation revealed Apgar scores of 8 at one minute and 9 at five minutes, hypothermia, depressed anterior fontanella, inadequate swallowing, mild respiratory distress syndrome, exotropia and pale optic discs. Neonatal brain ultrasound reconfirmed the diagnosis of hydranencephaly (Figs. 3 and 4), showing absence of cerebral hemispheres, presence of midbrain, thalami and cerebellum, and fluid filling of most of the calvarium, with an incomplete septum pellucidurn. Exitus occurred at age one day following several episodes of arterial hypotension and cyanosis. No extraordinary resuscitation attempts were made, and the patient’s heart was donated for transplant. Autopsy permission was not granted.
1, 1989
Fig. 3. Postnatal ultrasound study of the head in a coronal plane. Note the thalami and complete absence of the forebrain.
Fig. 4. Postnatal ultrasound study of the head in an axial plane through the temporal squama. Note the cerebellum and thalami surrounding by massive cerebrospinal fluid.
DISCUSSION We report a case of hydranencephaly with ultrasonographic prenatal diagnosis, confirmed by MRI. Uitrasonography is a convenient, inexpensive and
high resolution diagnostic tool widely used in prenatal diagnosis of fetal abnormalities.’ An alternative imaging technique seems necessary for cases of sonographically questionable fetal maldevelopment or when
Diagnosis of hydranencephaly
by MR 0 A.
a precise diagnosis is not made. Ultrasonographical recognition of a large intracranial fluid collection, for instance, may not suffice to differentiate between a large arachnoid cyst and an alobar holoprosencephaly. Differentiation between those two conditions through other imaging techniques, could result in radically different managements. Compared to ultrasonograms, current MRI techniques have less spatial resolution, lack real-time imaging capabilities, are costly and less versatile. MRI, however, provides a large diagnostic window allowing total fetal imaging with excellent resolution of tissue composition. MRI provides excellent visualization of a precise anatomical plane, allows easy interpretation of images of several planes, and permits computer-assisted reconstruction of multiple planes following one single study. Being more sophisticated than ultrasonography, MRI seems ideal for complex malformations. When compared to computerized tomography (CT) roentgenograms, MRI allows better resolution of some intracranial anomalies, permits direct imaging in multiple planes, does not use ionizing radiation and is less teratogenic.3 This case supports previous reports suggesting that,
ACUIRRE VILA-CORO AND R. DOMINICUEZ
107
although ultrasonography may remain as the primary intrauterine imaging method, MRI may become the ideal non-invasive complementary technique for selected cases.3-5 REFERENCES 1. Pilu, G.; Rizzo, N.; Orsini, L.F.; Bovicelli, L. Antenatal recognition of cerebral anomalies. Ultrasound Med. Biol. 12:319-326; 1986. 2. National Radiological Protection Board. Revised guidance on acceptable limits of exposure during nuclear magnetic clinical imaging. Brit. J. Radiof. 56:974-977;
1983.
3. McCarthy, S.M.; Filly, R.A.; Stark, D.D.; Callen, P.W.; Golbus, M.S.; Hrizak, H. Magnetic resonance imaging of fetal anomalies in utero: early experience. AJR 145: 677-682; 1985. 4, Stark, D.S.; McCarthy, S.M.; Filly, R.A.; Callen, P.W.; Hricak, H.; Parer, J.T. Intrauterine growth retardation: evaluation by magnetic resonance. Radiology 155:425427; 1985. 5. Turner, R.J.; Hankins, G.D.V.; Weinreb, J.C.; Ziaya, P.R.; Davis, T.N.; Lowe, T.W.; Gilstrap, III L.C. Magnetic resonance imaging and ultrasonography in the antenatal evaluation of conjoined twins. Am. J. Obstet.
Gynecol. 155:645-649; 1986.