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Current concepts of polymicrogyria.

Barkovich AJ - Neuroradiology (2010)

Bottom Line: Polymicrogyria is one of the most common malformations of cortical development.It has been known for many years and its clinical and MRI manifestations are well described.Recent advances in imaging, however, have revealed that polymicrogyria has many different appearances on MR imaging, suggesting that is may be a more heterogeneous malformation than previously suspected.

View Article: PubMed Central - PubMed

Affiliation: Neuroradiology, University of California at San Francisco, San Francisco, CA 94143-0628, USA. Jim.Barkovich@radiology.ucsf.edu

ABSTRACT
Polymicrogyria is one of the most common malformations of cortical development. It has been known for many years and its clinical and MRI manifestations are well described. Recent advances in imaging, however, have revealed that polymicrogyria has many different appearances on MR imaging, suggesting that is may be a more heterogeneous malformation than previously suspected. The clinical and imaging heterogeneity of polymicrogyria is explored in this review.

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Bilateral frontoparietal polymicrogyria. Axial (a) and coronal (b) T2-weighted images show a different appearance to the cortex, that of multiple radially oriented neuronal components separated by fibro-glial stroma. Note the prominent cerebellar fissures and the subcortical cerebellar cysts (arrows)
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Fig9: Bilateral frontoparietal polymicrogyria. Axial (a) and coronal (b) T2-weighted images show a different appearance to the cortex, that of multiple radially oriented neuronal components separated by fibro-glial stroma. Note the prominent cerebellar fissures and the subcortical cerebellar cysts (arrows)

Mentions: Bilateral frontoparietal polymicrogyria is another well-defined syndrome [12, 52]. Affected patients are characterized by global developmental delay of at least moderate severity, seizures, disconjugate gaze, and bilateral pyramidal and cerebellar signs [52]. MR demonstrates symmetric cortical dysgenesis affecting the frontoparietal regions most severely, as well as ventriculomegaly, bilateral white matter signal changes, and small brainstem and cerebellar structures with dysmorphic cerebellar cortex (Fig. 9). The presence of the white matter changes and the posterior fossa anomalies is very uncommon for polymicrogyria syndromes. In addition, the cortical malformation itself has a slightly different appearance than that of most polymicrogyria. Indeed, the overall appearance of the brain is more similar to that of the so-called cobblestone malformations, associated with congenital muscular dystrophies and resulting from abnormalities of linkage of radial glial cells to the pial basement membrane overlying the developing cortex [53, 54]. Further research has shown that the pial basement membrane is regulated by GPR56, the gene that causes BFPP when mutated [55], and that mutations of GPR56 cause gaps in the pial basement membrane and abnormal linkage of radial glial cells to that membrane [55]. Therefore, this disorder may fit better into the cobblestone malformations. Moreover, this observation raises the question of what precisely defines polymicrogyria and whether the different types of polymicrogyria should be analyzed and distinguished.Fig. 9


Current concepts of polymicrogyria.

Barkovich AJ - Neuroradiology (2010)

Bilateral frontoparietal polymicrogyria. Axial (a) and coronal (b) T2-weighted images show a different appearance to the cortex, that of multiple radially oriented neuronal components separated by fibro-glial stroma. Note the prominent cerebellar fissures and the subcortical cerebellar cysts (arrows)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2872023&req=5

Fig9: Bilateral frontoparietal polymicrogyria. Axial (a) and coronal (b) T2-weighted images show a different appearance to the cortex, that of multiple radially oriented neuronal components separated by fibro-glial stroma. Note the prominent cerebellar fissures and the subcortical cerebellar cysts (arrows)
Mentions: Bilateral frontoparietal polymicrogyria is another well-defined syndrome [12, 52]. Affected patients are characterized by global developmental delay of at least moderate severity, seizures, disconjugate gaze, and bilateral pyramidal and cerebellar signs [52]. MR demonstrates symmetric cortical dysgenesis affecting the frontoparietal regions most severely, as well as ventriculomegaly, bilateral white matter signal changes, and small brainstem and cerebellar structures with dysmorphic cerebellar cortex (Fig. 9). The presence of the white matter changes and the posterior fossa anomalies is very uncommon for polymicrogyria syndromes. In addition, the cortical malformation itself has a slightly different appearance than that of most polymicrogyria. Indeed, the overall appearance of the brain is more similar to that of the so-called cobblestone malformations, associated with congenital muscular dystrophies and resulting from abnormalities of linkage of radial glial cells to the pial basement membrane overlying the developing cortex [53, 54]. Further research has shown that the pial basement membrane is regulated by GPR56, the gene that causes BFPP when mutated [55], and that mutations of GPR56 cause gaps in the pial basement membrane and abnormal linkage of radial glial cells to that membrane [55]. Therefore, this disorder may fit better into the cobblestone malformations. Moreover, this observation raises the question of what precisely defines polymicrogyria and whether the different types of polymicrogyria should be analyzed and distinguished.Fig. 9

Bottom Line: Polymicrogyria is one of the most common malformations of cortical development.It has been known for many years and its clinical and MRI manifestations are well described.Recent advances in imaging, however, have revealed that polymicrogyria has many different appearances on MR imaging, suggesting that is may be a more heterogeneous malformation than previously suspected.

View Article: PubMed Central - PubMed

Affiliation: Neuroradiology, University of California at San Francisco, San Francisco, CA 94143-0628, USA. Jim.Barkovich@radiology.ucsf.edu

ABSTRACT
Polymicrogyria is one of the most common malformations of cortical development. It has been known for many years and its clinical and MRI manifestations are well described. Recent advances in imaging, however, have revealed that polymicrogyria has many different appearances on MR imaging, suggesting that is may be a more heterogeneous malformation than previously suspected. The clinical and imaging heterogeneity of polymicrogyria is explored in this review.

Show MeSH
Related in: MedlinePlus