Vibrational spectroscopies to investigate concretions and ectopic calcifications for medical diagnosis

Abstract

International audienceAs asserted by numerous authors, Fourier Transform (FT)-Raman and FT-Infrared spectroscopies constitute two useful tools for bio-medical diagnostics. We can distinguish two different kinds of application, namely, tissue disorders analyzed using statistical methods, and detection of ectopic calcifications through precise analysis of the shape and the position of absorption bands. In this contribution, we present some new results regarding these research themes, as well as recent experimental developments, such as the ability to perform nanometer scale near-field infrared microscopy, which have already led to major scientific breakthroughs

Raman chemical imaging, a new tool in kidney stone structure analysis: Case-study and comparison to Fourier Transform Infrared spectroscopy

“…Both methods are similar and complementary, but each has advantages and drawbacks regarding the resolution of spectra and imaging. Raman requires little sample preparation, and isn’t impeded by water or urea, which is useful in urolithiasis analysis [ 17 , 23 , 69 , 70 ]. In addition, it is commonly accepted that Raman has a better spatial resolution, instead of a lower spectral resolution and longer analysis time compared to FTIR microscopy [ 31 , 69 – 72 ].…”

“…The resolution can be improved by using a combination with other techniques like synchrotron, atomic force microscopy or ATR. A resolution of 10μm could be obtained using a FTIR microscopy with a synchrotron source for crystals deposits in renal biopsy with metal coated glass [ 70 ]. Obviously, this kind of sample preparation isn’t suitable for renal stones samples that measure several millimeters and cannot be sliced at the μm range.…”

Whitlockite structures in kidney stones indicate infectious origin: a scanning electron microscopy and Synchrotron Radiation investigation

“…Initial analysis was carried out at the hospital using a stereomicroscope for morphological typing and a FTIR spectrometer to accurately determine stone composition [60][61][62][63]. FT-IR experiments were performed in transmission mode using a FTIR spectrometer Vector 22 (Bruker Optics, Marne-la-Vallée, France) covering the mid-infrared range from 2.5 to 25 µm.…”

High frequency and wide range of human kidney papillary crystalline plugs

“…We also observed calcium and magnesium phosphate (whitlockite) in one individual. Whitlockite may be identified in infection stones and we previously identified by FTIR large amounts of whitlockite in incipient Randall's plaque [13,18,19]. The patient affected by whitlockite plugs had also abundant interstitial calcifications (Randall's plaque).…”