Probing focal cortical dysplasia in formalin fixed samples using tissue optical spectroscopy

Year: 2016

Authors: Anand S., Cicchi R., Giordano F., Buccoliero A.M., Conti V., Guerrini R., Pavone F.S.

Autors Affiliation: European Laboratory for Non-Linear Spectroscopy (LENS), University of Florence, Via Nello Carrara 1, Sesto Fiorentino, 50019, Italy; Department of Physics, University of Florence, Via Giovanni Sansone 1, Sesto Fiorentino, 50019, Italy; National Institute of Optics, National Research Council (INO-CNR), Largo Enrico Fermi 6, Florence, 50125, Italy; Division of Neurosurgery, Department of Neuroscience i, Anna Meyer Pediatric Hospital, Viale Gaetano Pieraccini 24, Florence, 50141, Italy; Division of Pathology, Department of Critical Care Medicine and Surgery, University of Florence, Viale Giovanni Battista Morgagni 85, Florence, 50134, Italy; Pediatric Neurology and Neurogenetics Unit, Department of Neuroscience, Pharmacology and Child Health, Anna Meyer Pediatric Hospital, Viale Pieraccini 24, Florence, 50139, Italy

Abstract: Focal cortical dysplasia (FCD) is one of most common causes of intractable epilepsy in pediatric population and these are often insensitive to anti-epileptic drugs. FCD is characterized by a disarray in localized regions of the cerebral cortex and abnormal neurons which results them to misfire with incorrect signals. Resective neurosurgery to remove or disconnect the affected parts from the rest of the brain seems to be a viable option to treat FCD. Before neurosurgery the subject could undergo imaging studies including magnetic resonance imaging (MRI) or computed tomography (CT) scans. On the downside FCD could be elusive in MRI images and may be practically invisible in CT scans. Furthermore, unnecessary removal of normal tissues is to be taken into consideration as this could lead to neurological defects. In this context, optical spectroscopy have been widely investigated as an alternative technique for the detection of abnormal tissues in different organ sites. Disease progression is accompanied by a number of architectural, biochemical and morphological changes. These variations are reflected in the spectral intensity and line shape. Here, in this proof of concept study we propose to investigate the application of tissue optical spectroscopy based on fluorescence excitation at two wavelength 378 and 445 nm coupled along with Raman spectroscopy for the detection of FCD on formalin fixed tissue specimens from pediatric subjects. For fluorescence at both the excitation wavelengths FCD showed a decreased intensity at longer wavelength when compared to normal tissues. Also, differences exist in the Raman spectral profiles of normal and FCD.

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KeyWords: Architectural acoustics; Diagnosis; Fluorescence; Formaldehyde; Histology; Magnetic resonance imaging; Neurology; Neurosurgery; Pediatrics; Principal component analysis; Tissue, Computed tomography scan; Excitation wavelength; Fluorescence excitation; Focal cortical dysplasias; Intractable epilepsies; Morphological changes; Optical spectroscopy; Pediatric population, Computerized tomography