TY - JOUR
T1 - Raman hyperspectral imaging detects novel and combinations of crystals in synovial fluids of patients with a swollen joint
AU - Niessink, Tom
AU - Kuipers, Charline
AU - Jong, Brighton Z. de
AU - Lenferink, Aufried T. M.
AU - Janssen, Matthijs
AU - Jansen, Tim L.
AU - Otto, Cees
N1 - Publisher Copyright:
© 2022 The Authors. Journal of Raman Spectroscopy published by John Wiley & Sons Ltd.
Funding Information:
The collaboration project is co-funded by the PPP Allowance made available by Health-Holland, Top Sector Life Sciences & Health, to Stichting ReumaNederland to stimulate public–private partnerships.
Publisher Copyright:
© 2022 The Authors. Journal of Raman Spectroscopy published by John Wiley & Sons Ltd.
PY - 2023/1
Y1 - 2023/1
N2 - The identification of synovial crystals is important for diagnosing rheumatic diseases. Currently, rheumatologists worldwide use compensated polarized light microscopy (CPLM) for crystal identification, but this technique is flawed. Raman spectroscopy might offer an objective, accurate alternative. We have tested Raman hyperspectral imaging on synovial fluid samples of 28 patients with swollen joints, measuring 5–10 crystals in each of these. Reference spectra for identification were measured using patient material, synthetic compounds, and oxalate kidney stones. Additionally, RRUFF and PANGAEA Raman databases were used to identify spectra. We identified the classical pathological crystals monosodium urate for gout and calcium pyrophosphate for calcium pyrophosphate deposition disease (CPPD). Hydroxyapatite, lipid spherules, and calcium oxalate monohydrate have also been observed and had been previously identified in synovial fluids. Other crystals, which were not previously observed in synovial fluid using CPLM, have been identified as well: calcite, aragonite, anatase, rutile, thenardite, dolomite, and a carotenoid. In addition, we found combinations of crystals in 13 out of 28 patients. We propose that the observed large variation of detectable crystals from a small population of patients and a small number of crystals per patient has significant ramifications for the use of compensated polarized light microscopy for the diagnosis of gout and CPPD. Further studies are required to learn the clinical significance of these crystals in human arthritis.
AB - The identification of synovial crystals is important for diagnosing rheumatic diseases. Currently, rheumatologists worldwide use compensated polarized light microscopy (CPLM) for crystal identification, but this technique is flawed. Raman spectroscopy might offer an objective, accurate alternative. We have tested Raman hyperspectral imaging on synovial fluid samples of 28 patients with swollen joints, measuring 5–10 crystals in each of these. Reference spectra for identification were measured using patient material, synthetic compounds, and oxalate kidney stones. Additionally, RRUFF and PANGAEA Raman databases were used to identify spectra. We identified the classical pathological crystals monosodium urate for gout and calcium pyrophosphate for calcium pyrophosphate deposition disease (CPPD). Hydroxyapatite, lipid spherules, and calcium oxalate monohydrate have also been observed and had been previously identified in synovial fluids. Other crystals, which were not previously observed in synovial fluid using CPLM, have been identified as well: calcite, aragonite, anatase, rutile, thenardite, dolomite, and a carotenoid. In addition, we found combinations of crystals in 13 out of 28 patients. We propose that the observed large variation of detectable crystals from a small population of patients and a small number of crystals per patient has significant ramifications for the use of compensated polarized light microscopy for the diagnosis of gout and CPPD. Further studies are required to learn the clinical significance of these crystals in human arthritis.
KW - calcium pyrophosphate arthritis
KW - diagnostics
KW - gout
KW - Raman hyperspectral imaging
KW - rheumatology
KW - UT-Hybrid-D
UR - http://www.scopus.com/inward/record.url?scp=85138668486&partnerID=8YFLogxK
U2 - 10.1002/jrs.6452
DO - 10.1002/jrs.6452
M3 - Article
SN - 0377-0486
VL - 54
SP - 47
EP - 53
JO - Journal of raman spectroscopy
JF - Journal of raman spectroscopy
IS - 1
ER -