Biometry extraction and probabilistic anatomical atlas of the anterior Visual Pathway using dedicated high-resolution 3-D MRI.

Anterior Visual Pathway (aVP) damage may be linked to diverse inflammatory, degenerative and/or vascular conditions. Currently however, a standardized methodological framework for extracting MRI biomarkers of the aVP is not available. We used high-resolution, 3-D MRI data to generate a probabilistic anatomical atlas of the normal aVP and its intraorbital (iOrb), intracanalicular (iCan), intracranial (iCran), optic chiasm (OC), and tract (OT) subdivisions. We acquired 0.6 mm3 steady-state free-precession images from 24 healthy participants using a 3 T scanner. aVP masks were obtained by manual segmentation of each aVP subdivision. Mask straightening and normalization with cross-sectional area (CSA) preservation were obtained using scripts developed in-house. A probabilistic atlas ("aVP-24") was generated by averaging left and right sides of all subjects. Leave-one-out cross-validation with respect to interindividual variability was performed employing the Dice Similarity Index (DSI). Spatially normalized representations of the aVP subdivisions were generated. Overlapping CSA values before and after normalization demonstrate preservation of the aVP cross-section. Volume, length, CSA, and ellipticity index (ε) biometrics were extracted. The aVP-24 morphology followed previous descriptions from the gross anatomy. Atlas spatial validation DSI scores of 0.85 in 50% and 0.77 in 95% of participants indicated good generalizability across the subjects. The proposed MRI standardization framework allows for previously unavailable, geometrically unbiased biometric data of the entire aVP and provides the base for future spatial-resolved, group-level investigations.

Long-Term Neuroradiological and Clinical Evaluation of NBIA Patients Treated with a Deferiprone Based Iron-Chelation Therapy.

Neurodegeneration with brain iron accumulation (NBIA) comprises various rare clinical entities with brain iron overload as a common feature. Magnetic resonance imaging (MRI) allows diagnosis of this condition, and genetic molecular testing can confirm the diagnosis to better understand the intracellular damage mechanism involved. NBIA groups disorders include: pantothenate kinase-associated neurodegeneration (PKAN), mutations in the gene encoding pantothenate kinase 2 (PANK2); neuroferritinopathy, mutations in the calcium-independent phospholipase A2 gene (PLA2G6); aceruloplasminemia; and other subtypes with no specific clinical or MRI specific patterns identified. There is no causal therapy, and only symptom treatments are available for this condition. Promising strategies include the use of deferiprone (DFP), an orally administered bidentate iron chelator with the ability to pass through the blood-brain barrier. This is a prospective study analysis with a mean follow-up time of 5.5 ± 2.3 years (min-max: 2.4-9.6 years) to define DFP (15 mg/kg bid)'s efficacy and safety in the continuous treatment of 10 NBIA patients through clinical and neuroradiological evaluation. Our results show the progressive decrease in the cerebral accumulation of iron evaluated by MRI and a substantial stability of the overall clinical neurological picture without a significant correlation between clinical and radiological findings. Complete ferrochelation throughout the day appears to be of fundamental importance considering that oxidative damage is generated, above, all by non-transferrin-bound iron (NTBI); thus, we hypothesize that a (TID) administration regimen of DFP might better apply its chelating properties over 24 h with the aim to also obtain clinical improvement beyond the neuroradiological improvement.