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Dual‐frequency irradiation CEST‐MRI of endogenous bulk mobile proteins
Author(s) -
Goerke Steffen,
Breitling Johannes,
Zaiss Moritz,
Windschuh Johannes,
Kunz Patrick,
Schuenke Patrick,
Paech Daniel,
Longo Dario L.,
Klika Karel D.,
Ladd Mark E.,
Bachert Peter
Publication year - 2018
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.3920
Subject(s) - nuclear magnetic resonance , proteome , chemistry , magnetic resonance imaging , in vivo , materials science , medicine , biochemistry , biology , physics , radiology , microbiology and biotechnology
A novel MRI contrast is proposed which enables the selective detection of endogenous bulk mobile proteins in vivo . Such a non‐invasive imaging technique may be of particular interest for many diseases associated with pathological alterations of protein expression, such as cancer and neurodegenerative disorders. Specificity to mobile proteins was achieved by the selective measurement of intramolecular spin diffusion and the removal of semi‐solid macromolecular signal components by a correction procedure. For this purpose, the approach of chemical exchange saturation transfer (CEST) was extended to a radiofrequency (RF) irradiation scheme at two different frequency offsets (dualCEST). Using protein model solutions, it was demonstrated that the dualCEST technique allows the calculation of an image contrast which is exclusively sensitive to changes in concentration, molecular size and the folding state of mobile proteins. With respect to application in humans, dualCEST overcomes the selectivity limitations at relatively low magnetic field strengths, and thus enables examinations on clinical MR scanners. The feasibility of dualCEST examinations in humans was verified by a proof‐of‐principle examination of a brain tumor patient at 3 T. With its specificity for the mobile fraction of the proteome, its comparable sensitivity to conventional water proton MRI and its applicability to clinical MR scanners, this technique represents a further step towards the non‐invasive imaging of proteomic changes in humans.