Frequency and cause of disagreements in imaging diagnosis in children with ventriculomegaly diagnosed prenatally
G M Senapati, D Levine, C Smith, J A Estroff, C E Barnewolt, R L Robertson, T Y Poussaint, T S Mehta, X Q Werdich, D Pier, H A Feldman, C D Robson, G M Senapati, D Levine, C Smith, J A Estroff, C E Barnewolt, R L Robertson, T Y Poussaint, T S Mehta, X Q Werdich, D Pier, H A Feldman, C D Robson
Abstract
Objectives: To assess the frequency and cause of variability in diagnosis on cranial sonography and magnetic resonance imaging (MRI) in children referred following prenatal diagnosis of ventriculomegaly.
Methods: Between 19 September 2003 and 16 March 2007, 119 infants with ultrasound and/or MRI studies performed within 13 months (median, 6 days) after birth, following prenatal referral for ventriculomegaly, were studied prospectively. There were 97 infants with ultrasound results and 53 with MRI, including 31 with both. Three sonologists and three pediatric neuroradiologists interpreted the postnatal ultrasound and MRI findings, blinded to prenatal diagnosis, and a final consensus diagnosis or group of diagnoses was obtained. Ventricular sizes as well as types of and reasons for any disagreement in diagnosis were recorded. Disagreements on a per patient basis were categorized as being major when they crossed diagnostic categories and had the potential to change patient counseling. Postnatal and prenatal diagnoses were compared.
Results: There was prospective agreement on 42/97 (43%) ultrasound and on 9/53 (17%) MRI readings. Prospective consensus was more likely when the number of central nervous system (CNS) anomalies was lower (P < 0.001 and P = 0.002 for ultrasound and MRI, respectively). In 24/55 (44%) ultrasound and 11/44 (25%) MRI examinations with disagreement in diagnosis, there was disagreement concerning the presence of ventriculomegaly. In 22/97 (23%) ultrasound studies and 22/53 (42%) MRI studies the disagreements were potentially important. Reasons for discrepancies in the reporting of major findings included errors of observation as well as modality differences in depiction of abnormalities. In comparing prenatal with postnatal diagnoses, there were 11/97 (11%) ultrasound and 27/53 (51%) MRI examinations with newly detected major findings, the most common being migrational abnormalities, callosal dysgenesis/destruction and interval development of hemorrhage.
Conclusion: Variability in postnatal CNS diagnosis is common after a prenatal diagnosis of ventriculomegaly. This is due in part to a lack of standardization in the definition of postnatal ventriculomegaly.
Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
Figures
Consensus study design.
Histogram of weeks of gestational age when prenatal imaging was performed for the 119 subjects in the final study population.
Coronal neonatal head ultrasound with the right ventricle measuring 9–11 mm and the left ventricle measuring 11–14 mm, diagnosed as normal by two sonologists and as ventriculomegaly by one sonologist.
Confidence of US and MR readers in postnatal diagnosis of fetal CNS abnormalities. Bars indicate mean ± standard error on a five-point scale from very confident to not confident. P-values from analysis of variance, adjusted for inter-reader and inter-subject variability.
Hemimegalencephaly misdiagnosed as hemorrhage on prenatal imaging. A. Axial single shot fast spin echo (SSFSE) T2WI at 22 weeks gestational age shows some areas of low signal intensity (arrowheads) felt to represent subependymal hemorrhage with dilatation of the right lateral ventricle at initial prenatal interpretation. The region of asymmetric enlargement and irregularity of the cortex (arrows) and generalized enlargement of the right cerebral hemisphere was not prospectively noted. B. Axial fast spin echo (FSE) T2WI on day 1 of life shows a mildly larger right cerebral hemisphere and polymicrogyria that is most marked in the right frontal lobe (arrows). There is abnormal hypointense signal within the right frontal white matter and basal ganglia. These findings are consistent with hemimegalencephaly.
Hemimegalencephaly misdiagnosed as hemorrhage on prenatal imaging. A. Axial single shot fast spin echo (SSFSE) T2WI at 22 weeks gestational age shows some areas of low signal intensity (arrowheads) felt to represent subependymal hemorrhage with dilatation of the right lateral ventricle at initial prenatal interpretation. The region of asymmetric enlargement and irregularity of the cortex (arrows) and generalized enlargement of the right cerebral hemisphere was not prospectively noted. B. Axial fast spin echo (FSE) T2WI on day 1 of life shows a mildly larger right cerebral hemisphere and polymicrogyria that is most marked in the right frontal lobe (arrows). There is abnormal hypointense signal within the right frontal white matter and basal ganglia. These findings are consistent with hemimegalencephaly.
Congenital CNS tumor as an error of observation. A. Sagittal SSFSE T2 weighted MRI at 36 weeks gestational age showed VM and a very subtle area of low signal intensity above the tectum (arrow). This was only noted in retrospect after postnatal MRI. B. Postnatal spin echo (SE) T1WI without contrast shows a mildy hyperintense mass above the tectum (arrow). This was felt to be a hamartoma or low grade glioma causing hydrocephalus due to obstruction at the level of the aqueduct.
Congenital CNS tumor as an error of observation. A. Sagittal SSFSE T2 weighted MRI at 36 weeks gestational age showed VM and a very subtle area of low signal intensity above the tectum (arrow). This was only noted in retrospect after postnatal MRI. B. Postnatal spin echo (SE) T1WI without contrast shows a mildy hyperintense mass above the tectum (arrow). This was felt to be a hamartoma or low grade glioma causing hydrocephalus due to obstruction at the level of the aqueduct.
Example of prenatal diagnosis being more accurate than postnatal diagnosis. A. Coronal SSFSE T2WI at 33 weeks gestational age shows ventriculomegaly and a region of porencephaly with slightly higher signal intensity fluid (arrow). B. Axial fast spin echo (FSE) T2 weighted MRI on day of life 27 (with a 2 month interval from fetal MRI) shows the extra-axial fluid appears contiguous with the ventricular system (arrow). Initial interpretation of the postnatal MR (blinded to prenatal diagnosis) included schizencephaly since the parenchyma appears to have a cortical rim (arrow) in the region of the defect. However, when interpreted in conjunction with the fetal MRI, the finding was felt to represent porencephaly. Additional findings on this image are dysmorphic ventriculomegaly with absence of the septum pellucidum and a large extra-axial fluid collection with midline shift. The patient had other features (not shown) consistent with lobar holoprosencephaly.
Example of prenatal diagnosis being more accurate than postnatal diagnosis. A. Coronal SSFSE T2WI at 33 weeks gestational age shows ventriculomegaly and a region of porencephaly with slightly higher signal intensity fluid (arrow). B. Axial fast spin echo (FSE) T2 weighted MRI on day of life 27 (with a 2 month interval from fetal MRI) shows the extra-axial fluid appears contiguous with the ventricular system (arrow). Initial interpretation of the postnatal MR (blinded to prenatal diagnosis) included schizencephaly since the parenchyma appears to have a cortical rim (arrow) in the region of the defect. However, when interpreted in conjunction with the fetal MRI, the finding was felt to represent porencephaly. Additional findings on this image are dysmorphic ventriculomegaly with absence of the septum pellucidum and a large extra-axial fluid collection with midline shift. The patient had other features (not shown) consistent with lobar holoprosencephaly.
Example of new development of an abnormality and error of observation. A. Sagittal (A) and axial (B) SSFSE T2 weighted MR at 31 weeks gestational age show the corpus callosum (arrowhead on A, short black arrow in B). Note also absent leaflets of the septum pellucidum (*) and left temporal schizencephaly (long arrow) with ventriculomegaly. C. Sagittal SE T1-weighted MR at 3 months of age shows deficiency in the anterior genu and rostrum of the corpus callosum (arrows) that was not appreciated on the prenatal MR. Note normal appearing body of corpus callosum, as seen prenatally (arrowhead). D,E. Axial FSE T2-weighted MR at 3 months of age show absent septal leaflets, deficiency of the anterior genu of the corpus callosum (black arrowhead) with associated dysmorphism of the frontal horns of the lateral ventricles and schizencephaly (long arrow). In addition there are subependymal neuronal heterotopia (white arrowheads) not visible on the prenatal study and not recorded by one of the neuroradiologists.
Example of new development of an abnormality and error of observation. A. Sagittal (A) and axial (B) SSFSE T2 weighted MR at 31 weeks gestational age show the corpus callosum (arrowhead on A, short black arrow in B). Note also absent leaflets of the septum pellucidum (*) and left temporal schizencephaly (long arrow) with ventriculomegaly. C. Sagittal SE T1-weighted MR at 3 months of age shows deficiency in the anterior genu and rostrum of the corpus callosum (arrows) that was not appreciated on the prenatal MR. Note normal appearing body of corpus callosum, as seen prenatally (arrowhead). D,E. Axial FSE T2-weighted MR at 3 months of age show absent septal leaflets, deficiency of the anterior genu of the corpus callosum (black arrowhead) with associated dysmorphism of the frontal horns of the lateral ventricles and schizencephaly (long arrow). In addition there are subependymal neuronal heterotopia (white arrowheads) not visible on the prenatal study and not recorded by one of the neuroradiologists.
Example of new development of an abnormality and error of observation. A. Sagittal (A) and axial (B) SSFSE T2 weighted MR at 31 weeks gestational age show the corpus callosum (arrowhead on A, short black arrow in B). Note also absent leaflets of the septum pellucidum (*) and left temporal schizencephaly (long arrow) with ventriculomegaly. C. Sagittal SE T1-weighted MR at 3 months of age shows deficiency in the anterior genu and rostrum of the corpus callosum (arrows) that was not appreciated on the prenatal MR. Note normal appearing body of corpus callosum, as seen prenatally (arrowhead). D,E. Axial FSE T2-weighted MR at 3 months of age show absent septal leaflets, deficiency of the anterior genu of the corpus callosum (black arrowhead) with associated dysmorphism of the frontal horns of the lateral ventricles and schizencephaly (long arrow). In addition there are subependymal neuronal heterotopia (white arrowheads) not visible on the prenatal study and not recorded by one of the neuroradiologists.
Example of new development of an abnormality and error of observation. A. Sagittal (A) and axial (B) SSFSE T2 weighted MR at 31 weeks gestational age show the corpus callosum (arrowhead on A, short black arrow in B). Note also absent leaflets of the septum pellucidum (*) and left temporal schizencephaly (long arrow) with ventriculomegaly. C. Sagittal SE T1-weighted MR at 3 months of age shows deficiency in the anterior genu and rostrum of the corpus callosum (arrows) that was not appreciated on the prenatal MR. Note normal appearing body of corpus callosum, as seen prenatally (arrowhead). D,E. Axial FSE T2-weighted MR at 3 months of age show absent septal leaflets, deficiency of the anterior genu of the corpus callosum (black arrowhead) with associated dysmorphism of the frontal horns of the lateral ventricles and schizencephaly (long arrow). In addition there are subependymal neuronal heterotopia (white arrowheads) not visible on the prenatal study and not recorded by one of the neuroradiologists.
Example of new development of an abnormality and error of observation. A. Sagittal (A) and axial (B) SSFSE T2 weighted MR at 31 weeks gestational age show the corpus callosum (arrowhead on A, short black arrow in B). Note also absent leaflets of the septum pellucidum (*) and left temporal schizencephaly (long arrow) with ventriculomegaly. C. Sagittal SE T1-weighted MR at 3 months of age shows deficiency in the anterior genu and rostrum of the corpus callosum (arrows) that was not appreciated on the prenatal MR. Note normal appearing body of corpus callosum, as seen prenatally (arrowhead). D,E. Axial FSE T2-weighted MR at 3 months of age show absent septal leaflets, deficiency of the anterior genu of the corpus callosum (black arrowhead) with associated dysmorphism of the frontal horns of the lateral ventricles and schizencephaly (long arrow). In addition there are subependymal neuronal heterotopia (white arrowheads) not visible on the prenatal study and not recorded by one of the neuroradiologists.
Source: PubMed