Dandy-Walker malformation complex: correlation between ultrasonographic diagnosis and postmortem neuropathology.
ABSTRACT This autopsy-based study was designed to evaluate sonographic and neuropathologic findings of fetuses diagnosed prenatally with Dandy-Walker malformation complex.
The retrospective study encompassed a series of 44 autopsy cases from 2 tertiary referral centers with a prenatal ultrasound diagnosis of Dandy-Walker malformation complex between 1995 and 2003. Ultrasound and pathology data from the cases and from age-matched controls were reviewed in a blinded manner. An unequivocal diagnosis of Dandy-Walker malformation complex from ultrasonography or pathology archival images required significant hypoplasia or aplasia of the cerebellar vermis.
Neuropathologic examination failed to confirm the prenatal diagnosis of Dandy-Walker malformation complex in 59% (26/44, 95% confidence interval [CI] 44-72) of the cases. After standardized reevaluation of high quality archival sonograms and pathology images, concordance remained poor at 55% (6/11 cases, 95% CI 28-79). Sonographic features that favored concordance included marked enlargement of the cisterna magna (> or = 10 mm), complete aplasia of the vermis, and a trapezoid-shaped gap between the cerebellar hemispheres. This latter finding contrasted with a keyhole-shaped gap in fetuses with no cerebellar neuropathology.
Correlation between a prenatal ultrasound diagnosis of Dandy-Walker malformation complex and autopsy neuropathology findings is poor. Unequivocal prenatal sonographic diagnosis of Dandy-Walker malformation complex should be reserved for cases with the classic findings of Dandy-Walker malformation, including enlargement of the cisterna magna, aplasia of the vermis, and a trapezoid-shaped, rather than keyhole-shaped, interhemispheric gap.
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ABSTRACT: Fetal magnetic resonance imaging (MRI) has become established as part of clinical practice in many centres worldwide especially when visualization of the central nervous system pathology is required. In this review we summarize the recent literature and provide an overview of fetal development and the commonly encountered fetal pathologies visualized with MRI and illustrated with numerous MR images. We aim to convey the role of fetal MRI in clinical practice and its value as an additional investigation alongside ultrasound yet emphasize the need for caution when interpreting fetal MR images especially where experience is limited.Developmental Medicine & Child Neurology 11/2010; 53(1):18-28. · 2.68 Impact Factor
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ABSTRACT: Post-mortem magnetic resonance imaging (PM MRI) of brain is increasingly used in clinical practice; understanding of normal PM contrast to noise ratio (CNR), T1 and T2 values relaxation times is important for optimisation and accurate interpretation of PM MRI. We obtained T1- and T2-weighted images at 1.5 T. In the first phase of the study, we calculated CNR in twelve brain regions in 5 newborn infants after death and compared this with CNR from 5 infants during life. In the second phase, we measured deep grey matter (GM) and white matter (WM) T1 post-mortem in 18 fetuses and T1 and T2 post-mortem 6 infants prior to autopsy. Phase I: post-mortem T1- and T2-weighted CNRs were lower in most brain regions than during life. Phase II: compared with in vivo, all post-mortem images lacked GM-WM contrast and had high T2-weighted WM signal intensity. Mean (SD) post-mortem T1 in white and deep gray matter were respectively 1898 (327)ms and 1514 (202)ms in fetuses (p>0.05) and 1234 (180)ms and 1016 (161)ms in infants and newborns (p>0.05). Mean (SD) post-mortem T2 was 283 (11)ms in WM and 182 (18)ms in deep GM in infants and newborns (p<0.001). Post-mortem T1 and T2 values are higher than those reported from live cases. The difference between T1 values in GM and WM reduce after death.European journal of radiology 02/2011; 81(3):e232-8. · 2.65 Impact Factor
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ABSTRACT: There is considerable confusion in the literature regarding the terminology usedwhen describing abnormalities of the cerebellum and of the vermis in particular. Terminology such as ‘closure of the fourth ventricle’, ‘craniocaudal growth of the vermis’ and ‘inferior vermian hypoplasia’, as well as the numbering (using Roman numerals) of the cerebellar lobules from anterior to posterior, has left us with the preconception and misconception that the vermis grows from superior to inferior, and that partial agenesis or hypoplasia always involves the inferior lobules. In light of recent advances in our understanding of the embryology of the cerebellum and cisterna magna, certain terminology and concepts can be demonstrated to be incorrect and should be abandoned. This Editorial reviews the normal development of the cerebellum, describing and dispelling several misconceptions regarding both normal and abnormal cerebellar development, with specific reference to the cerebellar vermis. Examples of cerebellar and vermian anatomy at pathology, in-vitro and in-vivo fetal magnetic resonance imaging (MRI) and pre- and postnatal imaging are reviewed and correlated with cerebellar embryology, phylogeny, somatotopic mapping and functional MRI. The evidence indicates that the cerebellar vermis develops more in a ventral to dorsal direction than in a superior to inferior one and, therefore, that the concept of ‘inferior vermian hypoplasia’ is incorrect. Three possible categories of vermian anomaly are seen: it may not necessarily be the inferior vermis that is hypoplastic; it may not only be the inferior vermis that is hypoplastic; or it may not be vermian hypoplasia at all. The term ‘inferior vermian hypoplasia’ should only be used if it can be proved that only the inferior vermis is abnormal. There is no generic term which encompasses all the various etiologies that can cause a small vermis; thus, more appropriate terminology may be ‘vermian hypoplasia’ or ‘vermian dysplasia’, with ‘neovermian hypoplasia’ in cases in which the central lobules are proved to be abnormal.Ultrasound in Obstetrics and Gynecology 02/2014; 43(2):123-36. · 3.56 Impact Factor