Sensitivity and specificity of CEST and NOE MRI in injured spinal cord in monkeys

Wang, Feng; Zu, Zhongliang; Wu, Tung‐Lin; Yan, Xinqiang; Lü, Ming; Yang, Pai‐Feng; Byun, Nellie; Reed, Jamie L.; Gore, John C.; Chen, Li Min

doi:10.1016/j.nicl.2021.102633

Cited by 9 publications

(11 citation statements)

References 35 publications

(62 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At relatively low saturation powers, the amplitude of the NOE effect at −3.5 ppm is usually larger than that of other CEST/NOE effects. It can be clearly observed in nearly all biological tissues, including the brain, 23,24 muscle, 37 kidney, 38 and spinal cord 39 . Previously, the NOE effect at −3.5 ppm has shown clinical interest in diagnosing tumors 23,40–45 .…”

Section: Introductionmentioning

confidence: 99%

NOE‐weighted imaging in tumors using low‐duty‐cycle2π‐CEST

Cui

Sun

2022

Magnetic Resonance in Med

Self Cite

View full text Add to dashboard Cite

Purpose: Nuclear Overhauser enhancement (NOE)-mediated CEST imaging at −3.5 ppm has shown clinical interest in diagnosing tumors. Multiple-pool Lorentzian fit has been used to quantify NOE, which, however, requires a long scan time. Asymmetric analysis of CEST signals could be a simple and fast method to quantify this NOE, but it has contamination from the amide proton transfer (APT) at 3.5 ppm. This work proposes a new method using an asymmetric analysis of a low-duty-cycle pulsed-CEST sequence with a flip angle of 360 • , termed 2π-CEST, to reduce the contribution from APT.Methods: Simulations were used to evaluate the capability of the 2π-CEST to reduce APT. Experiments on animal tumor models were performed to show its advantages compared with the conventional asymmetric analysis. Samples of reconstituted phospholipids and proteins were used to evaluate the molecular origin of this NOE. Results:The 2π-CEST has reduced contribution from APT. In tumors where we show that the NOE is comparable to the APT effect, reducing the contamination from APT is crucial. The results show that the NOE signal obtained with 2π-CEST in tumor regions appears more homogeneous than that obtained with the conventional method. The phantom study showed that both phospholipids and proteins contribute to the NOE at −3.5 ppm. Conclusion:The NOE at −3.5 ppm has a different contrast mechanism from APT and other CEST/NOE effects. The proposed 2π-CEST is more accurate than the conventional asymmetric analysis in detecting NOE, and requires much less scan time than the multiple-pool Lorentzian fit. K E Y W O R D S chemical exchange saturation transfer (CEST), magnetization transfer (MT), nuclear Overhauser enhancement (NOE), tumor

show abstract

Section: Introductionmentioning

confidence: 99%

NOE‐weighted imaging in tumors using low‐duty‐cycle2π‐CEST

Cui

Sun

2022

Magnetic Resonance in Med

Self Cite

View full text Add to dashboard Cite

show abstract

“…In recent studies, although the origins of the NOE(-3.5 ppm) effect have been assigned to aliphatic protons associated with mobile proteins and lipids (12,13,(16)(17)(18)(19), their relative contributions to the in vivo NOE(-3.5 ppm) signals remain incompletely understood. Further studies on this issue would be highly rewarding since the NOE(-3.5 ppm) imaging has shown great potential for applications on brain tumors (12,17,(20)(21)(22)(23)(24), Alzheimer's disease (25) and spinal cord injury (26), etc. NOE is a dipolar cross-relaxation between two nuclear spins at a close distance on a molecule (27)(28)(29).…”

Section: Introductionmentioning

confidence: 99%

Assignment of molecular origins of NOE signal at −3.5 ppm in the brain

Zhao

2023

Preprint

Self Cite

View full text Add to dashboard Cite

Purpose: Nuclear Overhauser Enhancement mediated saturation transfer effect, termed NOE(-3.5 ppm), is a major source of chemical exchange saturation transfer (CEST) MRI contrasts at 3.5 ppm in the brain. Previous phantom experiments have demonstrated that both proteins and lipids, two major components in tissues, have substantial contributions to NOE(-3.5 ppm) signals. Their relative contributions in tissues are informative for the interpretation of NOE(-3.5 ppm) contrasts that could provide potential imaging biomarkers for relevant diseases, which remain incompletely understood. Methods: Experiments on homogenates and supernatants of brain tissues collected from healthy rats, that could isolate proteins from lipids, were performed to evaluate the relative contribution of lipids to NOE(-3.5 ppm) signals. On the other hand, experiments on ghost membranes with varied pH, and reconstituted phospholipids with different chemical compositions were conducted to study the dependence of NOE(-3.5 ppm) on physiological conditions. Besides, CEST imaging on rat brains bearing 9L tumors and healthy rat brains was performed to analyze the causes of the NOE(-3.5 ppm) contrast variations between tumors and normal tissues, and between gray matter and white matter. Results: Our experiments reveal that lipids have dominant contributions to the NOE (-3.5 ppm) signals. Further analysis suggests that decreased NOE(-3.5 ppm) signals in tumors and higher NOE(-3.5 ppm) signals in white matter than in gray matter are mainly explained by changes in membrane lipids, rather than proteins. Conclusion: NOE(-3.5 ppm) could be exploited as a highly sensitive MRI contrast for imaging membrane lipids in the brain.

show abstract

“…Of these multiple signal sources in the Z‐spectrum, the MT from nonexchangeable protons to water via rNOEs has recently been shown to be useful in specifically detecting macromolecules such as proteins, 13,20–23 carbohydrate polymers, 12,14 and membrane lipids 24 . Its successful application is showing early potential for the evaluation of a variety of disorders, including osteoarthritis, 12 cancer, 13,25 stroke, 26 renal disease, 27 Alzheimer's disease, 23 and spinal cord injury 28 . This review article outlines the mechanisms and underlying theory of rNOE contrast, the different types of rNOE MRI experiments, and potential applications.…”

Section: Introductionmentioning

confidence: 99%

“…24 Its successful application is showing early potential for the evaluation of a variety of disorders, including osteoarthritis, 12 cancer, 13,25 stroke, 26 renal disease, 27 Alzheimer's disease, 23 and spinal cord injury. 28 This review article outlines the mechanisms and underlying theory of rNOE contrast, the different types of rNOE MRI experiments, and potential applications.…”

mentioning

confidence: 99%

The relayed nuclear Overhauser effect in magnetization transfer and chemical exchange saturation transfer MRI

et al. 2022

View full text Add to dashboard Cite

Magnetic resonance (MR) is a powerful technique for noninvasively probing molecular species in vivo but suffers from low signal sensitivity. Saturation transfer (ST) MRI approaches, including chemical exchange saturation transfer (CEST) and conventional magnetization transfer contrast (MTC), allow imaging of low‐concentration molecular components with enhanced sensitivity using indirect detection via the abundant water proton pool. Several recent studies have shown the utility of chemical exchange relayed nuclear Overhauser effect (rNOE) contrast originating from nonexchangeable carbon‐bound protons in mobile macromolecules in solution. In this review, we describe the mechanisms leading to the occurrence of rNOE‐based signals in the water saturation spectrum (Z‐spectrum), including those from mobile and immobile molecular sources and from molecular binding. While it is becoming clear that MTC is mainly an rNOE‐based signal, we continue to use the classical MTC nomenclature to separate it from the rNOE signals of mobile macromolecules, which we will refer to as rNOEs. Some emerging applications of the use of rNOEs for probing macromolecular solution components such as proteins and carbohydrates in vivo or studying the binding of small substrates are discussed.

show abstract

Sensitivity and specificity of CEST and NOE MRI in injured spinal cord in monkeys

Abstract: Graphical abstract

Cited by 9 publications

References 35 publications

NOE‐weighted imaging in tumors using low‐duty‐cycle2π‐CEST

NOE‐weighted imaging in tumors using low‐duty‐cycle2π‐CEST

Assignment of molecular origins of NOE signal at −3.5 ppm in the brain

The relayed nuclear Overhauser effect in magnetization transfer and chemical exchange saturation transfer MRI

Contact Info

Product

Resources

About