Line Scan Raman Microspectroscopy for Label-Free Diagnosis of Human Pituitary Biopsies

Abstract

Pituitary adenomas are neoplasia of the anterior pituitary gland and can be subdivided into hormone-producing tumors (lactotroph, corticotroph, gonadotroph, somatotroph, thyreotroph or plurihormonal) and hormone-inactive tumors (silent or null cell adenomas) based on their hormonal status. We therefore developed a line scan Raman microspectroscopy (LSRM) system to detect, discriminate and hyperspectrally visualize pituitary gland from pituitary adenomas based on molecular differences. By applying principal component analysis followed by a k-nearest neighbor algorithm, specific hormone states were identified and a clear discrimination between pituitary gland and various adenoma subtypes was achieved. The classifier yielded an accuracy of 95% for gland tissue and 84–99% for adenoma subtypes. With an overall accuracy of 92%, our LSRM system has proven its potential to differentiate pituitary gland from pituitary adenomas. LSRM images based on the presence of specific Raman bands were created, and such images provided additional insight into the spatial distribution of particular molecular compounds. Pathological states could be molecularly differentiated and characterized with texture analysis evaluating Grey Level Cooccurrence Matrices for each LSRM image, as well as correlation coefficients between LSRM images.

Morpho-Molecular Metabolic Analysis and Classification of Human Pituitary Gland and Adenoma Biopsies Based on Multimodal Optical Imaging

“…Our results show elevated lipid levels for all pituitary adenoma subtypes. Also changes in the collagen content based on Raman spectral analysis are in agreement with previous studies [20]. Second-level classification by PCA-SVM showed the high potential of the proposed approach to identify the different subtypes of pituitary adenomas.…”

“…To form a uniform line illumination, a Powell lens and cylindrical lens (both Thorlabs, Newton, NJ, USA) were implemented to shape the laser beam. The parameters of the spectrometer (Shamrock SR 303i, Andor Technology, Belfast, Northern Ireland) are described elsewhere [20]. In brief, the 300 l/mm grating blazed at 500 nm in the spectrometer had a spectral resolution of 0.5 nm.…”

“…OCT was correlated with H&E staining and collagen was identified as main biomarker. LSRM has been shown to give promising results in differentiation of pituitary gland, different pituitary adenomas as well as discrimination to the surrounding tissue, the periosteal layer [20]. Spectral analysis was able to discriminate between the subclasses of pituitary adenomas.…”

Probing metabolic alterations in breast cancer in response to molecular inhibitors with Raman spectroscopy and validated with mass spectrometry

“…High resolution maps of a few cells were acquired in a single rectangular requisition at 2 mm by 2 mm resulting in 50-500 pixels per cell dictated by the size of the cell. Acquired spectra were then smoothed, [34][35][36][37] background subtracted following literature methods 38,39 and nally normalized for further analysis (details provided in the Experimental section). The representative original Raman spectra acquired from each cell and step-by-step spectral processing were shown in Fig.…”

Raman imaging and statistical methods for analysis various type of human brain tumor

“…The nervous system tumors are one of the most common types of cancer in the world. 1 In this paper we analyzed various types of human brain tumor such as: gliosarcoma 2 , meningothelioma, anaplastic oligodendroglioma 3 , pituitary adenoma 4 , neurofibroma, testicular cancer metastasis to the brain and breast cancer. 5…”