Dandy-Walker variant
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- updated 12 Dec 2023:
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Dandy-Walker variant (DWv) is is a less severehistorical term that was previously used to describe posterior fossa anomaly than the classic Dandy-Walker malformation (DWM), characterised as partial vermian hypoplasia with partial obstruction to the fourth ventricle. It is considered on the lesser end of the disease spectrum in the Dandy-Walker continuum.
Terminology
This term was created to include thosecystic malformations that dodid not meet the criteria for Dandy-Walker malformation. However, however, some authors recommend to avoid it as therethe use of the term is a lack of specificity that may create some confusion. Instead, a more detailed anatomic descriptionnon-specific and is recommendedhighly discouraged 41.
Please refer to isolated inferior vermian hypoplasia for a broad discussion inof this defined entity.
Pathology
There is usually partial vermian hypoplasia with partial obstruction tofourth ventricle, but without enlargement of the posterior fossa
Radiographic features
Antenatal ultrasound
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the diagnosis of a Dandy-Walker variant can not be made definitely until the 18thweek of gestation as the inferior vermis does not form till then may show a connection between the cisterna magna and fourth ventricle-
the fourth ventricle is large but less dilated and better formed than the classic Dandy-Walker malformation1 the cerebellar hemispheres are hypoplastic but there is less severe hypoplasia of the inferior vermis
Differential diagnosis
On antenatal ultrasound consider:
communication between the fourth ventricle and the cisterna magna can be a normal finding up to ~18 weeks of gestationincorrect angulation of the scan may make the posterior fossa larger than usual
See also
-<p><strong>Dandy-Walker variant (DWv)</strong> is a less severe posterior fossa anomaly than the classic <a href="/articles/classic-dandy-walker-malformation">Dandy-Walker malformation (DWM</a>), characterised as partial <a title="Isolated inferior vermian hypoplasia" href="/articles/isolated-inferior-vermian-hypoplasia">vermian hypoplasia</a> with partial obstruction to the <a href="/articles/fourth-ventricle">fourth ventricle</a>. It is considered on the lesser end of the disease spectrum in the <a href="/articles/dandy-walker-continuum-3">Dandy-Walker continuum</a>.</p><h4>Terminology</h4><p>This term was created to include those malformations that do not meet the criteria for Dandy-Walker malformation, however, some authors recommend to avoid it as there is a lack of specificity that may create some confusion. Instead, a more detailed anatomic description is recommended <sup>4</sup>.</p><p>Please refer to <a href="/articles/isolated-inferior-vermian-hypoplasia">isolated inferior vermian hypoplasia</a> for a broad discussion in this defined entity.</p><h4>Pathology</h4><p>There is usually partial <a title="Isolated inferior vermian hypoplasia" href="/articles/isolated-inferior-vermian-hypoplasia">vermian hypoplasia</a> with partial obstruction to the <a href="/articles/fourth-ventricle">fourth ventricle</a>, but without enlargement of the posterior fossa.</p><h4>Radiographic features</h4><h5>Antenatal ultrasound</h5><ul>-<li>the diagnosis of a Dandy-Walker variant can not be made definitely until the 18<sup>th</sup> week of gestation as the inferior vermis does not form till then</li>-<li>may show a connection between the cisterna magna and fourth ventricle</li>-<li>the fourth ventricle is large but less dilated and better formed than the classic Dandy-Walker malformation <sup>1</sup>-</li>-<li>the cerebellar hemispheres are hypoplastic but there is less severe hypoplasia of the inferior vermis</li>-</ul><h4>Differential diagnosis</h4><p>On antenatal ultrasound consider:</p><ul>-<li>communication between the fourth ventricle and the cisterna magna can be a normal finding up to ~18 weeks of gestation</li>-<li>incorrect angulation of the scan may make the posterior fossa larger than usual</li>-</ul><h4>See also</h4><ul>-<li><a href="/articles/dandy-walker-malformation-1">Dandy-Walker continuum</a></li>-<li><a href="/articles/classic-dandy-walker-malformation">classic Dandy-Walker malformation</a></li>-<li><a href="/articles/classification-system-for-malformations-of-the-cerebellum">classification system for malformations of the cerebellum</a></li>- +<p><strong>Dandy-Walker variant (DWv)</strong> is a historical term that was previously used to describe posterior fossa cystic malformations that did not meet the criteria for Dandy-Walker malformation. However, the use of the term is non-specific and is highly discouraged <sup>1</sup>. Please refer to <a href="/articles/isolated-inferior-vermian-hypoplasia">isolated inferior vermian hypoplasia</a> for a broad discussion of this defined entity.</p><p>The term remains in use across many institutions and in the literature.</p><h4>See also</h4><ul>
- +<li><p><a href="/articles/classic-dandy-walker-malformation">Dandy-Walker malformation</a></p></li>
- +<li><p><a href="/articles/classification-system-for-malformations-of-the-cerebellum">classification system for malformations of the cerebellum</a></p></li>
References changed:
- 1. Whitehead M, Barkovich M, Sidpra J et al. Refining the Neuroimaging Definition of the Dandy-Walker Phenotype. AJNR Am J Neuroradiol. 2022;43(10):1488-93. <a href="https://doi.org/10.3174/ajnr.a7659">doi:10.3174/ajnr.a7659</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/36137655">Pubmed</a>
- 1. Estroff JA, Scott MR, Benacerraf BR. Dandy-Walker variant: prenatal sonographic features and clinical outcome. Radiology. 1992;185 (3): 755-8. <a href="http://radiology.rsna.org/content/185/3/755.abstract">Radiology (abstract)</a> - <a href="http://www.ncbi.nlm.nih.gov/pubmed/1438757">Pubmed citation</a><div class="ref_v2"></div>
- 2. Ecker JL, Shipp TD, Bromley B et-al. The sonographic diagnosis of Dandy-Walker and Dandy-Walker variant: associated findings and outcomes. Prenat. Diagn. 2000;20 (4): 328-32. <a href="http://dx.doi.org/10.1002/(SICI)1097-0223(200004)20:4<328::AID-PD806>3.0.CO;2-O">Prenat. Diagn. (link)</a> - <a href="http://www.ncbi.nlm.nih.gov/pubmed/10740206">Pubmed citation</a><div class="ref_v2"></div>
- 3. Entezami M, Albig M, Knoll U et-al. Ultrasound Diagnosis of Fetal Anomalies. Thieme. (2003) ISBN:1588902129. <a href="http://books.google.com/books?vid=ISBN1588902129">Read it at Google Books</a> - <a href="http://www.amazon.com/gp/product/1588902129?ie=UTF8&tag=radiopaediaor-20&linkCode=as2&camp=1789&creative=9325&creativeASIN=1588902129">Find it at Amazon</a><div class="ref_v2"></div>
- 4. Bosemani T, Orman G, Boltshauser E et-al. Congenital abnormalities of the posterior fossa. Radiographics. 2015;35 (1): 200-20. <a href="http://dx.doi.org/10.1148/rg.351140038">doi:10.1148/rg.351140038</a> - <a href="http://www.ncbi.nlm.nih.gov/pubmed/25590398">Pubmed citation</a><span class="auto"></span>
Sections changed:
- Syndromes
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- Obstetrics
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