Chemical Exchange Saturation Transfer Imaging in Neurological Disorders

Chemical Exchange Saturation Transfer (CEST) imaging is a magnetic resonance technique that sensitively detects low‐concentration biomolecules by exploiting the exchange of saturated protons between targeted metabolites and bulk water. In neurological disorders, CEST enables non‐invasive mapping of pH changes, protein content and metabolite distributions with spatial resolution comparable to conventional MRI. Variants such as Amide Proton Transfer (APT) and Nuclear Overhauser Effect (NOE) CEST have revealed metabolic alterations in conditions including acute stroke, glioma, neurodegeneration and demyelinating diseases. By selectively saturating exchangeable protons on amide, hydroxyl or amine groups, CEST generates contrast related to molecular concentration, exchange rate and local microenvironment. This approach complements diffusion and perfusion imaging, offering insights into tissue viability, blood–brain barrier integrity and treatment response. Recent advances in acquisition speed, multi‐pool fitting algorithms and machine learning have improved quantification, enabling dynamic studies of glucose uptake and real‐time evaluation of tumour metabolism. The global significance of CEST in neurology lies in its ability to monitor disease progression and therapeutic efficacy without exogenous contrast agents, thereby facilitating personalised management of neurological conditions.

Research from Nature Portfolio

Recent studies have introduced advanced quantification methods for CEST in brain tumours, improving both accuracy and computational efficiency. One approach employs an adaptive downsampling and least‐squares fitting algorithm to decompose multi‐pool CEST spectra in glioma models, yielding robust maps of amide proton transfer and semisolid magnetisation transfer with reduced noise sensitivity. This method revealed tumour‐specific contrasts at frequencies corresponding to creatine and nuclear Overhauser effects, which were obscured by conventional fitting. Another development applies a fast T1ρ‐weighted dynamic glucose‐enhanced MRI sequence in glioma patients, achieving sub-7-second temporal resolution. By monitoring glucose‐induced CEST changes during intravenous infusion, this technique delineated tumour regions with distinct perfusion and metabolic profiles, demonstrating potential for non-invasive assessment of glucose transport and therapy monitoring in brain neoplasms.

Chemical Exchange Saturation Transfer Imaging in Neurological Disorders publication trend

The graph below shows the total number of articles in chemical exchange saturation transfer imaging in neurological disorders across all publications each year (not limited to Nature Index journals).

Technical terms

Chemical Exchange Saturation Transfer (CEST): MRI technique that generates contrast by saturating exchangeable protons on metabolites, which transfer saturation to water, amplifying detection of low-concentration molecules.

Amide Proton Transfer (APT): CEST variant targeting amide protons in proteins and peptides, sensitive to pH and protein concentration.

Magnetisation Transfer Ratio asymmetry (MTRasym): A measure of CEST contrast calculated from differences in signal between positive and negative frequency offsets, indicating exchange effects.

Nuclear Overhauser Effect (NOE): Magnetisation transfer between non-exchangeable aliphatic protons and water, used in CEST to probe macromolecular composition.

Exchange-Dependent Relaxation Rate (AREX): Quantitative metric compensating for direct water saturation and relaxation effects, enabling more accurate estimation of exchange rates.

References

1. An overview of CEST MRI for non-MR physicists. EJNMMI Physics (2016).
2. Quantitative chemical exchange saturation transfer (CEST) MRI of glioma using Image Downsampling Expedited Adaptive Least-squares (IDEAL) fitting. Scientific Reports (2017).
3. Fast and Quantitative T1ρ-weighted Dynamic Glucose Enhanced MRI. Scientific Reports (2017).
4. Comparing different analysis methods for quantifying the MRI amide proton transfer (APT) effect in hyperacute stroke patients. NMR in Biomedicine (2014).
5. Chemical exchange saturation transfer MRI serves as predictor of early progression in glioblastoma patients. Oncotarget (2018).