Aberrant supracallosal longitudinal bundle: MR features, pathogenesis and associated clinical phenotype

Arrigoni, Filippo; Romaniello, Romina; Peruzzo, Denis; Righini, Andrea; Parazzini, Cecilia; Colombo, Paola; Bassi, Maria Teresa; Triulzi, Fabio; Borgatti, Renato

doi:10.1007/s00330-015-4084-6

Cited by 8 publications

(5 citation statements)

References 27 publications

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“…Aberrant or ectopic white matter tracts have been detected in a wide spectrum of brain malformations involving brainstem and corpus callosum26,35–40 as a result of defects in axonal guidance or other mechanisms. The advent of high-resolution MRI and DTI along with the advances in genetic technologies helped to define and expand human disorders of axon guidance and will probably contribute to the discovery of many additional similar conditions in the future.…”

Section: Discussionmentioning

confidence: 99%

Anterior Mesencephalic Cap Dysplasia: Novel Brain Stem Malformative Features Associated with Joubert Syndrome

Arrigoni

Romaniello

Peruzzo

et al. 2017

AJNR Am J Neuroradiol

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SUMMARY:In Joubert syndrome, the "molar tooth" sign can be associated with several additional supra-and infratentorial malformations. Here we report on 3 subjects (2 siblings, 8 -14 years of age) with Joubert syndrome, showing an abnormal thick bulging of the anterior profile of the mesencephalon causing a complete obliteration of the interpeduncular fossa. DTI revealed that the abnormal tissue consisted of an ectopic white matter tract with a laterolateral transverse orientation. Tractographic reconstructions support the hypothesis of impaired axonal guidance mechanisms responsible for the malformation. The 2 siblings were compound heterozygous for 2 missense variants in the TMEM67 gene, while no mutations in a panel of 120 ciliary genes were detected in the third patient. The name "anterior mesencephalic cap dysplasia," referring to the peculiar aspect of the mesencephalon on sagittal MR imaging, is proposed for this new malformative feature. ABBREVIATIONS:AMCD ϭ anterior mesencephalic cap dysplasia; CST ϭ corticospinal tract; IQ ϭ Intelligence Quotient; JS ϭ Joubert syndrome; SCP ϭ superior

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Section: Discussionmentioning

confidence: 99%

Anterior Mesencephalic Cap Dysplasia: Novel Brain Stem Malformative Features Associated with Joubert Syndrome

Arrigoni

Romaniello

Peruzzo

et al. 2017

AJNR Am J Neuroradiol

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“…The use of innovative functional imaging tools, such as fMRI and tractography techniques, for the study of underlying brain connections may allow to test this hypothesis. 16,17…”

Section: Discussionmentioning

confidence: 99%

“…The variable degree of cognitive impairment we detected, ranging from 93% in syndromic agenesis of corpus callosum plus to 64% in isolated nonsyndromic agenesis of corpus callosum patients, suggests disruption, during brain development, of the normal neuronal connections involved in cognitive functions. 7,17,20 Indeed, a disharmonic profile, frequently associated with memory deficits and learning disabilities, has also been observed in patients with normal or borderline general cognitive abilities. This neuropsychological profile may explain the subtle behavioral and social problems frequently reported in agenesis of corpus callosum subjects with normal intelligence and suggests the opportunity of a strict follow-up of their cognitive and behavioral abilities.…”

Section: Discussionmentioning

confidence: 99%

Clinical Characterization, Genetics, and Long-Term Follow-up of a Large Cohort of Patients With Agenesis of the Corpus Callosum

et al. 2016

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To gain a better understanding of the clinical and genetic features associated with agenesis of corpus callosum, we enrolled and characterized 162 patients with complete or partial agenesis of corpus callosum. Clinical and genetic protocols allowed us to categorize patients as syndromic subjects, affected by complex extra-brain malformations, and nonsyndromic subjects without any additional anomalies. We observed slight differences in sex ratio (56% males) and agenesis type (52% complete). Syndromic agenesis of corpus callosum subjects were prevalent (69%). We detected associated cerebral malformations in 48% of patients. Neuromotor impairment, cognitive and language disorders, and epilepsy were frequently present, regardless of the agenesis of corpus callosum subtype. Long-term follow-up allowed us to define additional indicators: syndromic agenesis of corpus callosum plus patients showed the most severe clinical features while isolated complete agenesis of corpus callosum patients had the mildest symptoms, although we observed intellectual disability (64%) and epilepsy (15%) in both categories. We achieved a definitive (clinical and/or genetic) diagnosis in 42% of subjects.

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“…This rare form of WMT structural abnormality has previously been described in a dysmorphic corpus callosum and in aberrant WMTs, such as the supracallosal longitudinal bundle, pontine tegmental cap dysplasia, and anterior mesencephalic cap dysplasia. 3,5,7 The underlying pathologic mechanism is unclear, though thought to be due to either the transient fetal WMTs failing to regress 39 or miswiring of WMTs caused by impaired axonal guidance. We additionally observed complete agenesis of the ipsilateral SLF in all 3 cases.…”

Section: Discussionmentioning

confidence: 99%

“…2 Existing dMRI tractography studies in non-MCD brain malformations have demonstrated different patterns of aberrant WM connections in patients sharing similar-appearing malformations. These studies help advance our understanding about the disease pathologic mechanisms [3][4][5][6][7] and may aid radiology practice. 8,9 Previous dMRI tractography studies in LIS and PMG included only small case series or single case reports.…”

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confidence: 99%

Characterizing White Matter Tract Organization in Polymicrogyria and Lissencephaly: A Multifiber Diffusion MRI Modeling and Tractography Study

Arrigoni

Peruzzo

Mandelstam

et al. 2020

AJNR Am J Neuroradiol

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BACKGROUND AND PURPOSE: Polymicrogyria and lissencephaly may be associated with abnormal organization of the undelying white matter tracts that have been rarely investigated so far. Our aim was to characterize white matter tract organization in polymicrogyria and lissencephaly using constrained spherical deconvolution, a multifiber diffusion MR imaging modeling technique for white matter tractography reconstruction. MATERIALS AND METHODS:We retrospectively reviewed 50 patients (mean age, 8.3 6 5.4 years; range, 1.4-21.2 years; 27 males) with different polymicrogyria (n ¼ 42) and lissencephaly (n ¼ 8) subtypes. The fiber direction-encoded color maps and 6 different white matter tracts reconstructed from each patient were visually compared with corresponding images reconstructed from 7 agematched, healthy control WM templates. Each white matter tract was assessed by 2 experienced pediatric neuroradiologists and scored in consensus on the basis of the severity of the structural abnormality, ranging from the white matter tracts being absent to thickened. The results were summarized by different polymicrogyria and lissencephaly subgroups.RESULTS: More abnormal-appearing white matter tracts were identified in patients with lissencephaly compared with those with polymicrogyria (79.2% versus 37.3%). In lissencephaly, structural abnormalities were identified in all studied white matter tracts. In polymicrogyria, the more frequently affected white matter tracts were the cingulum, superior longitudinal fasciculus, inferior longitudinal fasciculus, and optic radiation-posterior corona radiata. The severity of superior longitudinal fasciculus and cingulum abnormalities was associated with the polymicrogyria distribution and extent. A thickened superior fronto-occipital fasciculus was demonstrated in 3 patients. CONCLUSIONS:We demonstrated a range of white matter tract structural abnormalities in patients with polymicrogyria and lissencephaly. The patterns of white matter tract involvement are related to polymicrogyria and lissencephaly subgroups, distribution, and, possibly, their underlying etiologies. ABBREVIATIONS: CG ¼ cingulum; CMV ¼ cytomegalovirus; CSD ¼ constrained spherical deconvolution; DEC ¼ direction-encoded color; dMRI ¼ diffusion MRI; FOD ¼ fiber orientation distribution; HARDI ¼ high angular resolution diffusion imaging; IFOF ¼ inferior fronto-occipital fasciculus; ILF ¼ inferior longitudinal fasciculus; LIS ¼ lissencephaly; MCD ¼ malformation of cortical development; OR-PCR ¼ optic radiation-posterior corona radiata; PMG ¼ polymicrogyria; SBH ¼ subcortical band heterotopia; SFOF ¼ superior fronto-occipital fasciculus/Muratoff bundle; SLF ¼ superior longitudinal fasciculus; WMT ¼ white matter tract

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Aberrant supracallosal longitudinal bundle: MR features, pathogenesis and associated clinical phenotype

Abstract: • An aberrant longitudinal bundle can be detected above corpus callosum. • The presence of the supracallosal bundle is associated with intellectual disability. • The supracallosal bundle may represent a persistent dorsal fornix.

Cited by 8 publications

References 27 publications

Anterior Mesencephalic Cap Dysplasia: Novel Brain Stem Malformative Features Associated with Joubert Syndrome

Anterior Mesencephalic Cap Dysplasia: Novel Brain Stem Malformative Features Associated with Joubert Syndrome

Clinical Characterization, Genetics, and Long-Term Follow-up of a Large Cohort of Patients With Agenesis of the Corpus Callosum

Characterizing White Matter Tract Organization in Polymicrogyria and Lissencephaly: A Multifiber Diffusion MRI Modeling and Tractography Study

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