title: Constrained spherical deconvolution-based tractography to depict and characterize a case of "hyperplastic fornix dorsalis".
abstract: The authors report the relevance of Constrained Spherical Deconvolution (CSD)-based tractography in demonstrating and quantitatively assessing a complex midline structure malformation in a 9-year-old girl with moderate intellectual disability and thickening of corpus callosum (CC) body discovered through conventional MRI (cMRI). Color-encoded fractional anisotropy (FA) maps clearly demonstrated what the cMRI showed as a thicknening of CC: a green, longitudinal bundle running dorsally to the body of CC. A more complex midline maldevelopmental disorder was suspected. CSD-based tractography was performed to virtually dissect the anomalous supracallosal longitudinal bundle (SLB), CC, fornix, anterior commissure (AC) and cingula. In addition, DTI-derived metrics were calculated for each virtually dissected fiber tract. The tractography study evidenced projections of the anomalous SLB in left forceps minor and to parietal regions, and projections of the fornix in right forceps minor. CC virtual dissection showed no gross abnormality, and cingula appeared slightly less extended than normal. The considerable thinning of AC hampered its virtual dissection. DTI-derived metrics suggested alterations in fornix microstructure, attributable to higher fiber density. In investigating white matter, cMRI may not be sufficient in addressing and assessing possible anomalies, while advanced CSD-based tractography and DTI-derived metrics may prove helpful in depicting and characterizing white matter anomalies in developmental disorders.
authors.affiliation: Neuroradiology Department, Fondazione, IRCCS Istituto Neurologico C.Besta, Milano, Italy. Electronic address: contarino.v@istituto-besta.it.
authors.forename: Valeria Elisa
authors.initials: VE
authors.lastname: Contarino
authors.affiliation: Developmental Neurology Division, Fondazione IRCCS Istituto Neurologico C.Besta, Milano, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Bulgheroni
authors.affiliation: Neuroradiology Department, Fondazione, IRCCS Istituto Neurologico C.Besta, Milano, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Savoiardo
authors.affiliation: Developmental Neurology Division, Fondazione IRCCS Istituto Neurologico C.Besta, Milano, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Annunziata
authors.affiliation: Neuroradiology Department, Fondazione, IRCCS Istituto Neurologico C.Besta, Milano, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Aquino
authors.affiliation: Developmental Neurology Division, Fondazione IRCCS Istituto Neurologico C.Besta, Milano, Italy.
authors.forename: Daria
authors.initials: D
authors.lastname: Riva
authors.affiliation: Neuroradiology Department, Fondazione, IRCCS Istituto Neurologico C.Besta, Milano, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Erbetta
mesh_terms: D000328:Adult; D016880:Anisotropy; D001921:Brain / Q000473:pathology; D001931:Brain Mapping / Q000379:methods; D003116:Color; D003337:Corpus Callosum / Q000473:pathology*; D002658:Developmental Disabilities / Q000473:pathology*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D020712:Fornix, Brain / Q000473:pathology*; D005625:Frontal Lobe / Q000473:pathology; D006624:Hippocampus / Q000378:metabolism; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009412:Nerve Fibers / Q000473:pathology
keywords: Constrained spherical deconvolution-based tractography; Diffusion Tensor Imaging; Intellectual disability; Midline malformations; Supracallosal bundle