Search

Meningioma consistency is one of the most critical factors affecting the difficulty of surgery. Although many studies have attempted to predict meningioma consistency via magnetic resonance imaging findings, no definitive method has been established, because most have been based on qualitative evaluations. Therefore, the present study examined the potential of the T2 relaxation time (T2 value), a tissue-specific quantitative parameter, for assessment of meningioma consistency.Eighteen surgically treated meningiomas in 16 patients were included in the present study. Preoperatively, the T2 values of all meningiomas were calculated pixel by pixel, and a T2 value distribution map was generated. A total of 27 tumor specimens (multiple specimens were procured if heterogeneous) were taken from these meningiomas, with each localization identified intraoperatively using image guidance. The consistency of the specimens was measured with a durometer, originally a device for measuring the hardness of material such as elastic rubber, and their water content was subsequently measured using wet and dry measurements.A significant correlation was found between the T2 values of the matched locations identified by image guidance intraoperatively and the consistency measured using the durometer (r = -0.722; P0.01) and the water content (r = 0.621; P = 0.01). In addition, the water content correlated significantly with the durometer consistency (r = -0.677; P0.01).The T2 values could be a reliable quantitative predictor of meningioma consistency, and the T2 value distribution map, which elucidated the internal structure of the tumor in detail, could provide helpful information for surgical resection.

Purpose This study aimed to establish the topographical and zonal T2 patterns of multi-resolution MRI in medial tibial cartilage in a canine model of osteoarthritis (OA), initiated by the anterior cruciate ligament (ACL) transection surgery, and studied after 8-weeks and 12-weeks post-surgery. Methods Articular cartilage from healthy, two stages of contralateral, and of OA knees were quantitatively imaged by the MRI T2 protocols at two imaging resolutions (100 and 17.6 μm/pixel). The zonal T2 changes at five topographical locations (anterior (AMT), exterior (EMT), posterior (PMT), central (CMT) and interior (IMT) medial tibia) and subsequent two averaged regions (covered by meniscus and exposed) were analyzed. At each location, full-thickness cartilage was studied in four sub-tissue zones (superficial, transitional, upper and lower radial zones). Results Tissue degradation can be detected by measurable changes of T2, which is resolution- and orientation-dependent. T2 changes ranging from +28.82% increase (SZ, PMT) to -23.15% decrease (RZ1, AMT) in healthy to disease (8C), with the largest increase of T2 in the surface tissue. Various location-dependent patterns of degradation are found over the tibial surface, most commonly shown in early-stage OA (8C) on the anterior site, different from the posterior. Finally, the contralateral cartilage has specific degradation patterns, different from those in OA cartilage. Conclusions This is the first quantitative and highest multi-resolution characterization of cartilage at five topographical locations over the medial tibial plateau with fine zonal resolution in an animal model of OA, which would benefit future investigation of human OA in clinics.

One aspect of heritage science is to examine and, if possible, reduce the chemical and physical interactions between the restoration products and artworks’ constituent materials. This research aims to identify an alternative process to minimize the impact on materials and health risk for users when hypochlorite is used as biocide on stone materials. In this study, we tested a hydrogel comprised of sodium alginate as an inert matrix and hypochlorite ions as biocide agents for the removal of biological patinas from calcarenite Lecce samples. These biofilms resulted formed mainly by filamentous cyanobacteria and green microalgae. We carried out 1H-NMR T2 relaxation measurements to check the hydrogel’s cleaning efficacy on artificially bio-deteriorated samples through a portable NMR equipment. Simultaneously, optical microscopy and colorimetric measurements allowed the establishment of color differences induced by treatments. Our biocide hydrogel proved to be effective in removing microbial colonization from the surface of Lecce stone specimens and from a section of an altar rail in the rupestrian Church of San Pietro Barisano, located in the “Sassi of Matera”.

Purpose To quantitatively evaluate degeneration of articular cartilage using magnetic resonance imaging (MRI) T2 mapping before and after arthroscopic surgery for discoid lateral meniscus (DLM). Methods We retrospectively reviewed the medical records of patients who underwent arthroscopic reshaping surgery for symptomatic DLM from September 2013 to October 2017 and who had undergone follow-up for ≥2 years. MRI T2 relaxation examinations had been performed preoperatively and at 3, 6, 12, and 24 months postoperatively. The T2 relaxation times of the whole lateral femoral condyle and the tibial plateau were assessed. In addition, the lateral femoral condyle was divided into 3 subcompartmental areas: anterior, middle, and posterior. Results In total, 30 knees of 27 patients were included in this study. The patients’ mean age at operation was 13.3 years (range 6-23 years), and the mean follow-up period was 31.6 months. Saucerization alone was performed in 3 knees and saucerization with repair in 27 knees. The T2 relaxation time of the whole lateral femoral condyle was significantly increased at 3 and 6 months postoperatively and significantly decreased at 12 and 24 months. The T2 relaxation time of the whole lateral tibial plateau was significantly increased at 3 months postoperatively and significantly decreased at 24 months. The T2 relaxation time of the posterior subcompartment of the lateral femoral condyle was significantly increased at 3 months and significantly decreased at 12 and 24 months. Conclusions The T2 relaxation time of the lateral femorotibial joint cartilage increased at 3 and 6 months postoperatively and then had decreased at 12 and 24 months. Quantitative MRI allowed us to monitor the substantial changes in the cartilage during the early postoperative period and the recovery at the distant time point after reshaping surgery for DLM. Level of Evidence Level IV, case series

This article describes the use of placental magnetic resonance imaging (MRI) relaxation times in the in vivo assessment of placental function. It focuses on T2*-weighted placental MRI, the main area of the authors' research over the past decade. The rationale behind T2*-weighted placental MRI, the main findings reported in the literature, and directions for future research and clinical applications of this method are discussed. The article concludes that placental T2* relaxation time is an easily obtained and robust measurement, which can discriminate between normal and dysfunctional placenta. Placenta T2* is a promising tool for in vivo assessment of placental function.

Introduction Magnetic resonance imaging (MRI) is a well-established medical invention in modern medical technology diagnosis. It is a nondestructive, versatile, and sensitive technique with a high spatial resolution for medical diagnosis. However, MRI has some limitations in differentiating certain tissues, particularly tiny blood vessels, pathological to healthy tissues, specific tumors, and inflammatory conditions such as arthritis, atherosclerosis, and multiple sclerosis. The contrast agent (CA) assisted imaging is the best possible solution to resolve the limitations of MRI. Method The literature review was carried out using the keywords, “MRI, T1&T2 relaxation, MRI CAs, delivery and adverse effects, classification of CAs.” The tools used for the literature search were PubMed, Scopus, and Google Scholar. Result and Discussion The literature findings focus on MRI technique, limitations, and possible solutions. Primarily, the review focuses on the mechanism of CAs in image formation with detailed explanations of T1 and T2 relaxations, the mechanism of the MRI-CA image formations. This review presents the adverse effects of CA as well as available marketed formulations and recent patents to extent complete information about the MRI-CA. Conclusion MRI generates detailed visual information of various tissues with high resolution and contrast. The proton present in the biological fluid plays a crucial role in MR image formation, and it is unable to distinguish pathological conditions in many cases. The CAs are the best solution to resolve the limitation by interacting with native protons. The present review discusses the mechanism of CAs in contrast enhancement and its broad classification with the latest literature. Furthermore, the article presents information about CA biodistribution and adverse effects. The review concludes with an appropriate solution for adverse effects and presents the future prospective for researchers to develop advanced formulations.

T2 relaxation time (T2) alterations may serve as markers for early detection and disease progression monitoring by reflecting brain microstructural integrity in Alzheimer's disease (AD). However, the characteristics of T2 alterations during the early stage of AD remain elusive. We explored T2 alterations and their possible correlations with cognitive function in 5XFAD mice at early ages (1, 2, 3, and 5 months of age). Voxel-based analysis (VBA) and region of interest (ROI) analysis showed a decreased T2 in the hippocampus of 2-, 3-, and 5-month-old 5XFAD mice compared to those of controls. The dorsal hippocampal T2 decreased earlier than the ventral hippocampus T2. A significant correlation was observed between Morris water maze (MWM) test cognitive behavior and the dorsal hippocampus T2 in 5XFAD mice. These results indicated that the microstructural integrity of brain tissues, particularly the hippocampus, was impaired early and the impairment became more extensive and severe during disease progression. Furthermore, the dorsal hippocampus is a crucial component involved in spatial cognition impairment in young 5XFAD mice.

Objective. The aims of this study were to compare the temporomandibular joint (TMJ) retrodiscal tissue T2 relaxation times between patients with temporomandibular disorders (TMDs) and asymptomatic volunteers and to assess the diagnostic potential of this approach. Study Design. Patients with TMD (n = 173) and asymptomatic volunteers (n = 17) were examined by using a 1.5-T magnetic resonance scanner. The imaging protocol consisted of oblique sagittal, T2-weighted, 8-echo fast spin echo sequences in the closed mouth position. Retrodiscal tissue T2 relaxation times were obtained. Additionally, disc location and reduction, disc configuration, joint effusion, osteoarthritis, and bone edema or osteonecrosis were classified using MRI scans. The T2 relaxation times of each group were statistically compared. Results. Retrodiscal tissue T2 relaxation times were significantly longer in patient groups than in asymptomatic volunteers (P < .01). T2 relaxation times were significantly longer in all of the morphologic categories. The most important variables affecting retrodiscal tissue T2 relaxation times were disc configuration, joint effusion, and osteoarthritis. Conclusion. Retrodiscal tissue T2 relaxation times of patients with TMD were significantly longer than those of healthy volunteers. This finding may lead to the development of a diagnostic marker to aid in the early detection of TMDs.

The aim of this study was to develop and assess a method of quantifying cartilage T2 relaxation times in a series of volumes of interest (VOIs) covering the entire cartilage of the femoral condyles. Subsequently, the method was used to test for T2 spatial variations in non-osteoarthritic (OA) knees.Ten non-OA subjects (five female, average 30 years) were enrolled after informed consent. Three-dimensional bone and cartilage models were created by double echo steady state (DESS) morphological magnetic resonance image (MRI) segmentation, and the models were semi-manually registered with multi-slice, multi-echo (MSME) T2 MRI. Mean T2 values were calculated for 12 VOIs derived from cartilage thickness literature and their respective superficial and deep layers.Analyses showed that intra- and inter-rater reliabilities of the presented method were "good" to "excellent" in more than 90% of the VOIs. Additionally, several spatial differences in T2 values were observed, including, for the medial condyle, higher T2 values in the anterior and central VOIs versus in the posterior VOI (p .05). T2 values were also generally higher in the superficial versus deep layers (p .05).The presented MRI T2 analysis method is reliable and provides a comprehensive quantification of spatial heterogeneity of healthy cartilage compositional properties. This method can be further applied to better understand knee OA pathophysiology and potentially define clinically relevant diagnostic features of the disease.

BACKGROUND: Understanding the association between MR parameters and age related deterioration in human intervertebral disks forms an important step in the development of clinical diagnostic protocols for disk disease. METHODS: Ten unfixed thoracic and lumbar cadaver disk joints, age 37–81 years were imaged at 9.4 T using T2 relaxation (CPMG) and ADC (DWI spin echo) MR protocols. For each MR parameter, spatial maps were computed from the axial images, with the AF and NP segmented based on the T2 maps. Linear regression tested for the correlation between mean and variance (COV) of T2 and ADC with age in the disk, nucleus and annulus, and the effect of thoracic vs. lumbar spine on these correlations. FINDINGS: In the disk, age negatively correlated with mean ADC (P < 0.001) and positively with COV of ADC (P < 0.001) and T2 (P < 0.05). Age was negatively correlated with mean T2 (P < 0.01), mean ADC (P < 0.001) and positively with COV of ADC (P < 0.001) and T2 (P < 0.05) in the NP and positively correlated with mean T2 (P < 0.05), COV of ADC (P < 0.01) and T2 (P < 0.05) and negatively with mean ADC (P < 0.05) in the AF. Compared to thoracic disks, lumbar disks showed higher mean ADC (P < 0.05), lower mean T2 (P < 0.001) and higher COV of ADC (P < 0.01) and T2 (P < 0.05). INTERPRETATION: Compared to T2, MR diffusion was a more sensitive measure of age mediated changes in disk tissues. Strong differences in the association of MR parameters with age between the lumbar and thoracic suggest that mechanical environment effects tissue specific MR parameters’ association with age.

This JACC Scientific Expert Panel provides consensus recommendations for an update of the cardiovascular magnetic resonance (CMR) diagnostic criteria for myocardial inflammation in patients with suspected acute or active myocardial inflammation (Lake Louise Criteria) that include options to use parametric mapping techniques. While each parameter may indicate myocardial inflammation, the authors propose that CMR provides strong evidence for myocardial inflammation, with increasing specificity, if the CMR scan demonstrates the combination of myocardial edema with other CMR markers of inflammatory myocardial injury. This is based on at least one T2-based criterion (global or regional increase of myocardial T2 relaxation time or an increased signal intensity in T2-weighted CMR images), with at least one T1-based criterion (increased myocardial T1, extracellular volume, or late gadolinium enhancement). While having both a positive T2-based marker and a T1-based marker will increase specificity for diagnosing acute myocardial inflammation, having only one (i.e., T2-based OR T1-based) marker may still support a diagnosis of acute myocardial inflammation in an appropriate clinical scenario, albeit with less specificity. The update is expected to improve the diagnostic accuracy of CMR further in detecting myocardial inflammation.

High quality tissue-mimicking phantoms (TMPs) have a critical role in the preclinical testing of emerging modalities for diagnosis and therapy. TMPs capable of accurately mimicking real tissue in Magnetic Resonance guided Focused Ultrasound (MRgFUS) applications should be fabricated with precise T1 and T2 relaxation times. Given the current popularity of the MRgFUS technology, we herein performed a systematic review on the MR relaxation properties of different phantoms types. Polyacrylamide (PAA) and agar based phantoms were proven capable of accurately replicating critical thermal, acoustical, and MR relaxation properties of various body tissues. Although gelatin phantoms were also proven factional in this regard, they lack the capacity to withstand ablation temperatures, and thus, are only recommended for hyperthermia applications. Other gelling agents identified in the literature are Poly-vinyl alcohol (PVA), Polyvinyl Chloride (PVC), silicone, and TX-150/ TX-151; however, their efficacy in thermal studies is yet to be established. PAA gels are favorable in that they offer optical transparency enabling direct visualization of coagulative lesions. On the other hand, agar phantoms have lower preparation costs and were proven very promising for use with the MRgFUS technology, without the toxicity issues related to the preparation and storage of PAA materials. Remarkably, agar turned out to be the prominent modifier of the T2 relaxation time even for phantoms containing other types of gelling agents instead of agar. This review could be useful in manufacturing realistic MRgFUS phantoms while simultaneously indicating an opportunity for further research in the field with a particular focus on the MR behavior of agar-based TMPs.

Direct measurement of the liquid-solid mass transfer coefficient in packed beds is achieved using T 2 - T 2 relaxation exchange NMR. This method directly probes molecular exchange between intra- and inter-pellet fluid, rather than requiring a net flux between phases as in conventional methods. Mass transfer coefficients measured using the NMR method are compared with literature values and two widely used correlations. For Reynolds number, Re , less than 0.2, the mass transfer coefficients measured using NMR show excellent agreement with the correlations over the flow conditions for which they were developed. The approach also enables the quantification of mass transfer in the limit of, and at, zero flow. At Re = 0, the Sherwood number in packed beds with voidage of 0.41 determined by NMR is found to approach 9, in good agreement with previously reported results, but significantly greater than that predicted by extrapolating well-known correlations beyond their range of validity to Re = 0.

We present a proof-of-concept study focusing on a method for the intra- and inter-center validation and harmonization of data obtained from MRI T1 and T2 maps. The method is based on a set of MnCl2 samples that provide in-scan ground-truth reference values regardless of the details of the MRI protocol. The relaxation times of MnCl2 aqueous solutions were first measured by means of an NMR laboratory relaxometer, as a function of concentration and temperature. The obtained T1 and T2 values, once renormalized at the scanner temperature, were used as reference values for the MRI mapping measurements of the MnCl2 relaxation times. By using different clinical MRI scanners and sequences, we found a good agreement for standard and turbo sequences (limits of agreement: 5% for IR, SE, IR-TSE; 10% for TSE), while an under-estimation and an over-estimation were found respectively for MOLLI and T2-prep TrueFISP, as already reported in the literature. The linearity of the relaxation rates with the concentration predicted by the Solomon-Bloembergen-Morgan theory was observed for every dataset at all temperatures, except for T2-prep TrueFISP maps results. Some preliminary results of an in vivo experiment are also presented.

The T1 and T2 relaxation times of some nitrogen-containing liquids were measured by 14N pulse nuclear magnetic resonance (NMR) in the magnetic field of 0.575 T. The liquids measured in this paper were energetic and toxic substances as well as some electrolytes. A method of the fast discrimination of dangerous liquids by the low field 14N NMR relaxation parameters was proposed. It is shown that flammable and toxic nitrogen-based liquids have small values of T1 and T2, therefore these liquids may be discriminated from the group of less dangerous liquids.

Double and zero quantum filtered (ZQF/DQF) 2H NMR spectroscopy was used to study D2O in five different Nafion membranes, N117, N115, NR212, XL, and HP, in order to assess the effectiveness of the technique for monitoring differences in thickness, membrane reinforcement, and the addition of chemical stabilizers. Experiments were also carried out at 20 and 80 °C to understand if the ZQF/DQF technique could detect changes in the water environments and exchange dynamics as a function of temperature. For two of the membranes, significant decreases in the 1/T2 relaxation rates were observed at 80 °C. The two modified membranes showed changes in the quadrupolar couplings when heated, with the XL membranes showing a drop in the coupling and the HP membranes showing an increase in the coupling. No consistent variations could be associated with thickness, reinforcement or the addition of stabilizers. Overall the technique was able to detect some differences between the membranes but was limited by the variability in the observed NMR data.

Objectives To evaluate microstructural cerebral changes in children with neurofibromatosis type 1 (NF1) based on T2 relaxation time measurements at 3Tesla. Methods From our dataset of pediatric MRI examinations at 3T 19 pediatric NF1 patients (1.9–14.3 years of age, 9 girls, 10 boys) were retrospectively selected and compared with the previously published group of 44 healthy children (0–16 years of age). MRI examination included a triple echo TSE sequence as basis for T2 maps. T2 relaxation times were measured in 37 brain regions. Results Compared with healthy controls, T2 relaxation times had the tendency to be increased by 1.01% (GM) to 11.85% (dentate nucleus) for NF1 patients. Only in posterior limb of the internal capsule and parietooccipital white matter values were reduced. No differences were observed between both hemispheres. Overall, no strong evidence supporting a difference between NF1 patients with and without optic glioma or with normal and impaired neuropsychological development was observed. Conclusions Using T2 relaxation times it was possible to describe measurable microstructural differences in multiple brain regions between NF1 patients and healthy children regardless of whether signal abnormalities were visible on conventional images.

To gain a better understanding of disintegration actions, 11 different disintegrants were tested. Model tablets were prepared with various preparation conditions, and their disintegration time and tensile strength were measured. The present study also investigated various physicochemical properties of the model tablets and disintegrant powders, including wetting time, water absorption ratio, particle size, morphological observation, swelling property, and T2 relaxation time (T2). The experimental data were thoroughly analyzed using self-organizing map (SOM) clustering. The test disintegrants were classified into four distinct clusters. It is worth noting that superdisintegrants, including croscarmellose sodium (Ac-Di-Sol), sodium starch glycolate (Glycolys), and crospovidone (Kollidone CL-F and Polyplasdon XL-10), were assigned to clusters different from those of normal disintegrants. Furthermore, SOM clustering suggested the latent contributions of factors to the disintegration actions. The disintegrant content had a significant impact on the disintegration actions. Furthermore, the T2 measurements indicated that the interaction mode of crospovidone with water was different from those of cellulose- and starch-based disintegrants. The evidence obtained is valuable information for the formulation design of tablets.

Objective To examine age-related changes in T2 relaxation times during infancy and childhood in order to assess T2 values obtained from routine MRI as a biomarker. Methods From our pool of clinical pediatric MRI examinations at 3 T all patients with normal conventional MRI scans were retrospectively selected. Depending on their clinical findings the identified 99 patients (0–199 months) were divided into 43 healthy controls and 56 diseased children with various clinical abnormalities (developmental delay, epilepsy, prematurity, and deafness). T2 maps based on routinely performed triple echo turbo spin echo sequences were created. T2 values were measured in 22 brain regions to determine age-related changes. We also investigated whether such changes differ between healthy and diseased children. Results Age significantly reduced T2 relaxation times across all regions (p Conclusions Using T2 maps based on clinical MRI data we could determine age-related T2 relaxation times in 22 brain regions during infancy and childhood. Our data have relevance for future investigator independent T2 relaxation time measurements in determining whether T2 values are within the normal range or should be considered as potentially pathologic.

A two-dimensional low-field nuclear magnetic resonance (LF-NMR) T1-T2 relaxation technique was developed to contrast the water status evolution during different cooking procedures (steam and boiling cooking). Meat quality, water distribution, microstructure and protein properties were determined. The results showed that steamed meats had lower cooking loss and shear force, but higher redness, proton relaxation intensity (T1 and T2) and proton density than boiled meats. The differences in water distribution between the two cooking procedures appeared at approximately 40 °C, with acceleration at 60 °C, and the most remarkable difference was shown at 80 °C. Boiling resulted in more damage to muscle structure and greater protein denaturation than steam cooking. Meanwhile, α-helixes and β-turns increased, but β-sheets and random coils decreased in steamed meats compared with boiled meats. Changes in microstructural and protein properties were closely associated with water status evolution in cooked meat during cooking.

Purpose To investigate the performance of combined T2 mapping and T2 iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) in orbital tissues to predict the therapeutic efficacy of intravenous glucocorticoids (IVGCs) for active and moderate-to-severe thyroid-associated ophthalmopathy (TAO). Method Sixty-three active and moderate-to-severe TAO patients (responsive group, n = 35; unresponsive group, n = 28) who underwent orbital MRI before receiving IVGCs were retrospectively enrolled. Baseline clinical characteristics and imaging parameters were analyzed and compared between the two groups of different therapeutic efficacy. Binary logistic regression analysis was conducted to determine the independent predictors, the predictive performance of which was evaluated using receiver operating characteristic curve analysis. Results The mean T2 relaxation time of extraocular muscle (EOM-T2RTmean) (P = 0.001), maximum T2RT of EOM (EOM-T2RTmax) (P = 0.001), mean water fraction of EOM (EOM-WFmean) (P Conclusions Pretherapeutic quantitative measurements, based on combining T2 mapping and T2 IDEAL in orbital tissues, are valuable for predicting IVGC treatment response in active and moderate-to-severe TAO. EOM-T2RTmean and EOM-WFmax may become promising IVGC treatment response predictors.

The application of time-domain NMR (TD-NMR) analysis to quantify water content in pharmaceutical ingredients is demonstrated. The initial phase of the study employed a range of disintegrants with defined amounts of added water (0-30% of the total weight) as samples; the disintegrants included croscarmellose sodium, corn starch, low-substituted hydroxypropyl cellulose, and crospovidone. After acquisition of the T2 relaxation curves of the samples by TD-NMR measurements, these curves were analyzed by partial least squares (PLS) regression. According to the analysis, accurate and reliable PLS models were created that enabled accurate assessment of water content in the samples. A powder blend consisting of acetaminophen (paracetamol) and tablet excipients was also examined. Both a physical mixture of the powder blend and a wet granule prepared with a high-speed granulator were tested as samples in this study. Precise determination of water content in the powder blend was achieved by using the TD-NMR method. The accuracy of water content determination was equivalent to or better than that of the conventional loss on drying method. TD-NMR analysis samples were measured nondestructively and rapidly with low cost; thus, it could be a powerful quantitative method for determining water content in pharmaceuticals.

This study investigated the effect of high-pressure treating time (HPTT) on the tenderness of reduced-fat reduced-salt (RFRS) meat gels. The result of shear force value showed that the RFRS meat gels exhibited excellent tenderness treated with 200 MPa for 3 min. The mechanism of tenderness enhancement was revealed from the perspective of water migration characteristics in meat batters. After HPP, the characteristics of water molecules in meat batters were investigated using low-field nuclear magnetic resonance (LF-NMR) T2 relaxometry. The datas of T2 relaxation time and peak area indicated the free water changed into immobilized water significantly. The result of principal components analysis showed that the sample treated with a proper HPPT (3 min) was significantly different from the others. The tenderness of RFRS meat gel products was improved with the application of 200 MPa, especially treated with 3 min. The improvement of tenderness could be ascribed to the increase of immobilized water. The possible increase of the diameter in three-dimensional gel network might lead to more water molecules entrapped.

Magnetic resonance imaging (MRI) is a powerful technique for observing the function of specific cells and molecules inside living organisms. However, compared to optical microscopy, in which fluorescent protein reporters are available to visualize hundreds of cellular functions ranging from gene expression and chemical signaling to biomechanics, to date relatively few such reporters are available for MRI. Efforts to develop MRI-detectable biomolecules have mainly focused on proteins containing or transporting paramagnetic metals for T1 and T2 relaxation enhancement or large numbers of exchangeable protons for chemical exchange saturation transfer. While these pioneering developments established several key uses of biomolecular MRI, such as imaging of gene expression and functional biosensing, they also revealed that low molecular sensitivity poses a major challenge for broader adoption in biology and medicine. Recently, new classes of biomolecular reporters have been developed based on alternative contrast mechanisms, including enhancement of spin diffusivity, interactions with hyperpolarized nuclei, and modulation of blood flow. These novel reporters promise to improve sensitivity and enable new forms of multiplexed and functional imaging.

A wide range of direct 13C and indirect 1H-[13C] MR detection methods exist to probe dynamic metabolic pathways in the human brain. Choosing an optimal detection method is difficult as sequence-specific features regarding spatial localization, broadband decoupling, spectral resolution, power requirements and sensitivity complicate a straightforward comparison. Here we combine density matrix simulations with experimentally determined values for intrinsic 1H and 13C sensitivity, T1 and T2 relaxation and transmit efficiency to allow selection of an optimal 13C MR detection method for a given application and magnetic field. The indirect proton-observed, carbon-edited (POCE) detection method provides the highest accuracy at reasonable RF power deposition both at 4 T and 7 T. The various polarization transfer methods all have comparable performances, but may become infeasible at 7 T due to the high RF power deposition. 2D MR methods have limited value for the metabolites considered (primarily glutamate, glutamine and γ-amino butyric acid (GABA)), but may prove valuable when additional information can be extracted, such as isotopomers or lipid composition. While providing the lowest accuracy, the detection of non-protonated carbons is the simplest to implement with the lowest RF power deposition. The magnetic field homogeneity is one of the most important parameters affecting the detection accuracy for all metabolites and all acquisition methods.

ObjectiveIsolated lateral compartment tibiofemoral radiographic osteoarthritis (IL-ROA) is an understudied form of knee osteoarthritis (OA). The objective of the present study was to characterize Magnetic Resonance Imaging (MRI) abnormalities and MR-T2 relaxation time measurements associated with IL-ROA and with isolated medial compartment ROA (IM-ROA) compared with knees without OA.Method200 case subjects with IL-ROA (Kellgren/Lawrence (K/L) grade≥2 and joint space narrowing (JSN)>0 in the lateral compartment but JSN=0 in the medial compartment) were randomly selected from the Osteoarthritis Initiative baseline visit. 200 cases with IM-ROA and 200 controls were frequency matched to the IL-ROA cases. Cases and controls were analyzed for odds of having a subregion with >10% cartilage area affected, with ≥25% bone marrow lesions (BML), with meniscal tear or maceration, and for association with cartilage T2 values.ResultsIL-ROA was more strongly associated with ipsilateral MRI knee pathologies than IM-ROA (IL-ROA: OR=135.2 for size of cartilage lesion, 95% CI 42.7-427.4; OR=145.4 for large size BML, 95% CI 41.5-509.5; OR=176 for meniscal tears, 95% CI 59.8-517.7; IM-ROA: OR=28.4 for size of cartilage lesion, 95% CI 14.7-54.7; OR=38.1 for size of BML, 95% CI 12.7-114; OR=37.0 for meniscal tears, 95% CI 12-113.6). Cartilage T2 values were higher in both tibial and medial femoral compartments in IL-ROA, but in IM-ROA were only significantly different from controls in the medial femur.ConclusionIL-ROA knees show a greater prevalence and severity of MRI lesions and higher cartilage T2 values than IM-ROA knees compared with controls.

Atherosclerosis can lead to most cardiovascular diseases. Although some biomimetic nanomaterials coated by macrophage membranes have been reported in previous studies of atherosclerosis, to our knowledge, no studies regarding the detection of early lesions of atherosclerosis (foam cells) using such a strategy have yet been reported. In the present study, Fe3O4 biomimetic nanoparticles coated with a macrophage membrane (Fe3O4@M) were prepared to investigate the imaging effect on the early lesions of atherosclerosis (foam cells). The results showed that the Fe3O4@M particles are spheres with average diameters of approximately 300 nm. T1 and T2 relaxation values showed that the ratio of r2 to r1 was 26.09. The protein content accounted for approximately 27% of the total weight in Fe3O4@M, and Fe3O4@M nanoparticles exhibited high biosafety. Further testing showed that Fe3O4@M effectively targets early atherosclerotic lesions by the specific recognition of integrin α4β1 to VCAM-1. Taken together, Fe3O4@M is a promising contrast agent for the diagnosis of early stage atherosclerosis.

Crystallization of glucose is a natural process that could occur in honey due to several reasons and glucose is one of them. In this study, a non-conventional TD-NMR pulse sequence, Magic Sandwich Echo (MSE), was used to monitor the crystallization of honey at 14 degrees C. Honey samples were seeded with glucose to induce crystallization. T-1 and T-2 relaxation times were also measured during 96 h of storage. Mono-exponential and bi-exponential relations were used to explain T-1 and T-2, respectively. As a complementary method to NMR, crystal melting enthalpy was measured by differential scanning calorimetry (DSC). High correlations were detected between NMR and DSC results. T-1 relaxation times did not change, whereas both components of T-2 decreased with increasing time. In addition to crystallization, the melting of crystallized honey was performed at 50 degrees C inside the NMR system. Crystal melting was monitored in real-time, and the rate of crystal removal was fitted to a monoexponential decay model.

Maternal nutritional status has long lasting consequences on meat quality in offspring. We sought to determine how maternal vitamin D3 would influence quality traits of longissimus dorsi muscle in offspring pigs during postmortem storage. A total of 72 offspring pigs (150 d, Duroc × Landrace × Yorkshire) obtained from 3 sow feeding groups (9 sows per group) which contained 200 (low vitamin D3, LD), 800 (normal vitamin D3, ND) and 3200 (high vitamin D3, HD) IU of vitamin D3/kg basal diet during pregnancy to investigate the effects of maternal vitamin D3 status during pregnancy on meat quality attributes such as pH, shear force, water holding capacity (WHC), color, and low-field nuclear magnetic resonance (LF-NMR) T2 relaxation times of longissimus dorsi muscles in meat samples of offspring pigs during postmortem storage. The results showed that during postmortem storage times, HD group had higher pH value and WHC, while lower T21 relaxation time compared with LD group (P

Quantification of fluid and organic matter content of shale samples are principal goals of petrophysical and geochemical evaluation of shales that are essential to determine reservoir quality. While volumetric methods to characterize shales are cumbersome and destructive, 1H magnetic resonance (MR) methods are robust, fast, and non-destructive. However, short-lived MR signal lifetimes of shale samples challenge existing MR methods and motivate the development of new MR methods. Two-dimensional (2D) MR T 1 - T 2 relaxation correlation is a powerful method to differentiate hydrogen-bearing species in porous materials. However, the experimental echo time limitation of the T 1 - T 2 method precludes acquisition of important short lifetime signal components. In addition, due to overlap of signal components in T 1 - T 2 correlations, quantification accuracy is impaired in shales. Here, we introduce the 2D MR T 1 - T 2 ∗ relaxation correlation measurement for quantitative determination of shale 1H components. Liquid-rich shale samples from the Eagle Ford Formation were used in adsorption/desorption and evaporation experiments. 2D MR T 1 - T 2 and T 1 - T 2 ∗ correlations coupled with gravimetric measurements were performed to identify water, oil/bitumen, and kerogen peaks in the relaxation correlation maps. Peaks associated with shale components showed significant contrast in T 1 - T 2 ∗ correlations. This allowed quantitative measurement of water and oil content using the signal intensity of each peak.

Delineation of the viscosity in heavy-oil reservoirs is viable for heavy-oil exploration and production activities. Low-field nuclear magnetic resonance (NMR) relaxometry has proven to be a powerful tool for a downhole assessment of heavy-oil viscosity. This prediction is derived from the sensitive relationship between viscosity- and NMR-measured properties, such as spin-spin ( T 2 ) and spin-lattice ( T 1 ) relaxation. In this paper, we demonstrate the versatility of NMR relaxometry by presenting three different approaches for obtaining viscosity correlations that incorporate T 1 , T 2 , and hydrogen-index (HI) data as a function of temperature and five inter-echo spacings ( TE ) to account for the signal loss of fast-relaxing components in heavy oil. The results of this work show that NMR-relaxometry measurements correlate very well with heavy-oil viscosities and that each methodology demonstrates reasonable success with heavy-oil predictions. In addition, these relationships demonstrate substantial correlation improvement, especially in comparison with other published relationships that are also tested. Lastly, insight regarding heavy-oil-sample storage time and emulsion is briefly discussed to emphasize the significance of fluid-sample handling within the scheme of heavy-oil viscosity prediction and core/fluid-analysis protocols. Viscosities predicted with a correlation derived from aged and emulsified samples were observed to be within a 17% error in comparison with those predicted with a correlation developed from recently collected heavy oils. From a well-logging point of view, the uncertainty introduced by using aged samples for the interpretation of well-logging data is not considered excessive and may be correctable. These results give new and valuable insight into the considerations that are necessary for sufficient core and fluid analysis.

相对单个超顺磁氧化铁纳米颗粒(SPIO),在相同铁浓度条件下,SPIO纳米团簇明显具有更强的弛豫效能和更高的磁共振成像对比度。研究如何控制SPIO团簇大小以及一些其他结构参数,从而进一步提高其磁学性能有重要意义。本文研究了磁性纳米团簇中SPIO纳米晶体间距大小与其弛豫性能之间的关系。本文使用两亲性高分子聚乙二醇-聚酯自组装制备磁性纳米团簇,并加入不同量的刚性小分子胆固醇作为媒介嵌入至SPIO纳米晶体之间调控SPIO晶体间距,然后使用小角X射线散射技术精确测量其间距大小。结果显示,实验制备的SPIO纳米团簇具有优异的弛豫效能,且随着胆固醇量的增加SPIO纳米晶体间距也随之变大。此外,控制SPIO纳米晶体间距能够有效调控磁性纳米团簇的饱和磁化强度和T 2弛豫效率,并可通过降低其间距以获得更好的磁共振对比度。

The effects of different size particles and contents of sugarcane dietary fiber(SDF) on water state, water holding capacity(WHC), gel strength and microstructure of myofibrillar protein gels was studied. It was found that gel strengths were improved with the increase in SDF particle size and content, and the value of water holding capacity (WHC) reached a maximum with the addition of 80-mesh SDF at 2%. Discrete exponential fitting analysis and multi-exponential function analysis of the T2 relaxation time revealed that three categories of water, each having different mobility states in the gels, had different effects on the blended gel systems. Also, the intrinsic T21 relaxation time of immobile water in gels containing SDF was shorter than that in pure gels. Pronounced differences in myofibrillar gel network structures were observed during heating at 80 °C for 20 min. The fractal dimension which was determined by the box count method and the pore density (diameter

Zero echo time (ZTE) imaging at 9.4T was used to assess local water saturation level in the tight sandstone rocks. The results were compared with the industry standard porosity estimation basing on T2 relaxation analysis at 0.05T. A linear dependence between the two was achieved. This suggests the possibility to use 3D ZTE method for assessment of local amount of water in rocks. The method can be applicable in investigation of water saturation processes in tight rocks, where imaging methods based on spin echo like RARE failed due to short T2, while single point imaging (SPI) is impractical due to long acquisition time.

A multi-analytical and multi-dimensional approach was used to investigate the effect of moisture and gluten on physico-chemical properties of shelf-stable ready to eat (RTE) pasta. Moisture and frozen water contents were not affected by formulation nor storage time. Hardness and retrograded amylopectin significantly increased during storage in all samples, more markedly in pasta with the lowest moisture content. Higher amounts of water and gluten reduced pasta hardening and contributed to control RTE pasta quality. (1)H FID became steeper in all samples during storage, but no effect of high moisture and gluten levels was observed on the mobility of these protons. Three proton T2 populations were observed (population C, population D and population E). Population C and D were not resolved during all storage. (1)H T2 relaxation time of the most abundant population (population E) shifted to shorter times and the amount of protons increased during storage, more importantly in the samples with lower moisture and gluten content.

This study explores the possibilities for application of 1H Time Domain Nuclear Magnetic Resonance (1H TD-NMR) as a rapid method for assessment of milk quality. Whey, urea, hydrogen peroxide, synthetic urine and synthetic milk were added to the milk samples at concentrations of 5, 15, 25, 35 and 50% v/v. Discrete exponential analysis of the 1H TD-NMR relaxation decay revealed that the milk samples contained a single water component as well as that the T2 relaxation times differed significantly with respect to the level of adulteration. Regression models obtained with the full 1H TD-NMR (multivariate approach) and T2 value (univariate approach) demonstrate a strong correlation to estimate the level of adulteration in milk samples, with standard errors of prediction of 2.34 and 3.79% v/v, respectively. SIMCA and kNN classification models were developed to classify control from adulterated milk samples and adulterated milk samples based on the level of adulteration. The results obtained with both models showed a similar and quite satisfactorily predictability, with sensitivity and specificity ranging from 0.66 to 1.00. This study clearly demonstrates that 1H TD-NMR could be applied as an alternative rapid method for detecting and quantifying milk adulteration.

Water dynamics and protein denaturation in surf clam during heating were studied by the two-dimensional low-field nuclear magnetic resonance (LF-NMR) T1-T2 relaxation technique. A significant change was found for clam around 80 °C and direct visualization of the water state change was provided by the magnetic resonance imaging. Principal components and heatmap analysis revealed that clam treated at 80–100 °C located at different region from those treated at 40–70 °C. The clams heated at 80 °C showed a maximum water holding capability, and significant microstructure change. The differential scanning calorimetry analysis indicated a denaturation of protein when the temperature was over 80 °C. The hardness and chewiness had a maximum value at 80 and 70 °C, respectively. The color parameter L* showed a significant increase when temperature was over 80 °C. This demonstrated that the T1-T2 technique has potential in evaluating water dynamics for surf clam during heating.

In this study, several methods such as mercury intrusion porosimetry (MIP) and nuclear magnetic resonance (NMR) for characterizing the pore throat size distribution of tight sandstone reservoirs were selected. The differences of mercury injection parameters such as maximum interconnected pore throat radius, median radius, mercury injection curve, and pore throat distribution curve of oil-bearing and oil-free samples were compared. By designing the algorithm program and using the mercury injection data, the coefficient of converting the T2 relaxation time to the pore-throat radius was corrected, and the pore throat distribution of different oil saturation samples were analyzed. Environmental scanning electron microscope (ESEM) was also used to observe the microscopic pores and the oil in them. Using the above data, we systematically analyzed the control of pore throat distribution on the oiliness. It is found that the oiliness depends on the maximum interconnected pore throat radius, and the oil saturation depends on the oil migration front pressure and pore volume. The oiliness of tight sand has good relationship with pore throat size distribution, and the better reservoir petrophysical properties result in better oiliness. Statistics on the pore throat size distribution of oil-bearing tight sands were carried out and main intervals of pore throat size distribution of oil-bearing reservoirs were given in this paper. This understanding provides a basis for searching sweet spots in the future exploration of the tight oil.

Lipid migration is widespread in food system and has an important effect on food quality. It is urgent to explore the lipid migration in egg yolk after heating. The content of lipids in upper part (HL) was higher than that in bottom part (LL), and the lipids migration in yolk gel under heating were confirmed by MRI (T1) and T2 relaxation time of LF-NMR. Subsequently, the XDR result demonstrated the high lipid content induced the decrease in crystallinity of protein in HL part. The structures of HL part trend to be more ordered, stable (β-sheet & β-turns) and flat (α-helices) than LL part, also, more water distributed in LL part were observed by FTIR spectrum. The SEM results revealed that lipids migrated from LL to HL part, eventually lead to the protein in HL part of heated yolk gel unfold, the globular structure collapsed and become flatter. Morever, ethyl acetate, hexanal, etc. and hexanal, ethyl acetate, dimethyl-silanediol, etc. were identified as the main VOCs of LL and HL part of heated yolk gel, respectively. Lipid migration result in more lipid-specific volatiles were formed in the HL part, such as hexanal, 3-hydroxy-cyclohexanone, 2-pentyl-furan, d -limonene, 2-ethyl-1-hexanol, benzeneacetaldehyde. Lipid migration in heated yolk gel, caused by heat treatment, resulted in the changes of structure and flavor between HL and LL part.

The aim of this study was to evaluate the transverse relaxation time of methylene resonance as compared to other lipid resonances. The examinations were performed using a 3.0 T scanner with a point-resolved spectroscopy (PRESS) sequence. Lipid relaxation time in a lipid phantom filled with canola oil was estimated with a repetition time (TR) of 6000ms and echo time (TE) of 40-550ms. For in vivo proton magnetic resonance spectroscopy ((1)H-MRS), eight male Sprague-Dawley rats were given free access to a normal-chow (NC) and another eight male Sprague-Dawley rats were given free access to a high-fat (HF) diet. Both groups drank water ad libitum. T2 measurements in the rats' livers were conducted at a fixed TR of 6000ms and TE of 40-220ms. Exponential curve fitting quality was calculated through the coefficients of determination (R(2)). Chemical analyses of the phantom and livers were not performed, but T2 decay curves were acquired. The T2 relaxation time of methylene resonance was estimated as follows: NC rats, 37.1±4.3ms; HF rats, 31.4±1.8ms (p

Cardiac magnetic resonance (CMR) provides a high signal-to-noise ratio, high spatial and temporal resolutions, as well as a delayed-enhancement sequence and is therefore considered a reference technique in the field of cardiac imaging. However, currently available sequences are not adequate to assess some pathologic conditions, such as myocardial edema. T2 mapping sequences generate parametric images that are based on the transverse relaxation time (T2) for each voxel. In case of edema, the T2 relaxation time is longer. This review summarizes current knowledge on CMR T2 mapping for assessing myocardial edema.

The objective of this study was to elucidate the influence on quantitative analysis using LCModel with the condition of echo time (TE) longer than the recommended values in the spectrum acquisition specifications.A 3T magnetic resonance system was used to perform proton magnetic resonance spectroscopy. The participants were 5 healthy volunteers and 11 patients with glioma. Data were collected at TE of 72, 144 and 288ms. LCModel was used to quantify several metabolites (N-acetylaspartate, creatine and phosphocreatine, and choline-containing compounds). The results were compared with quantitative values obtained by using the T2-corrected internal reference method.In healthy volunteers, when TE was long, the quantitative values obtained using LCModel were up to 6.8-fold larger (p0.05) than those obtained using the T2-corrected internal reference method. The ratios of the quantitative values obtained by the two methods differed between metabolites (p0.05). In patients with glioma, the ratios of quantitative values obtained by the two methods tended to be larger at longer TE, similarly to the case of healthy volunteers, and large between-individual variation in the ratios was observed.In clinical practice, TE is sometimes set longer than the value recommended for LCModel. If TE is long, LCModel overestimates the quantitative value since it cannot compensate for signal attenuation, and this effect is different for each metabolite and condition. Therefore, if TE is longer than recommended, it is necessary to account for the possibly reduced reliability of quantitative values calculated using LCModel.

Introduction The intent of this study was to differentiate intracranial tumors using the metabolite concentrations obtained by quantification with correction for T2 relaxation time, and to analyze whether the spectrum peak was generated by the existence of metabolites in proton magnetic resonance spectroscopy (MRS). Methods All proton MRS studies were performed on a clinical 1.5T MR system. 7 normal volunteers and 57 patients (gliomas, metastases, meningiomas, acoustic neuromas, and pituitary adenomas) underwent single voxel proton MRS with different echo times (TE: 68, 136, 272 ms) for T 2 correction of signal derived from metabolites and tissue water. With tissue water employed as an internal reference, the concentrations of metabolite (i.e. N-acetylaspartate (NAA), total creatine (t-Cr) and choline-containing compounds (Cho)) were calculated. Moreover, proton MRS data of previously published typical literatures were critically reviewed and compared with our data. Results Extramedullary tumors were characterized by absence of NAA compared with intramedullary tumors. High-grade glioma differed from low-grade glioma by lower t-Cr concentrations. Metastasis differed from cystic glioblastoma by higher Cho concentrations, lower t-Cr concentrations, an absence of NAA, and a prominent Lipids peak. Based on these results and review of previous reports, we suggest a clinical pathway for the differentiation of intracranial tumors. Conclusion The metabolite concentrations obtained by quantification with correction for T 2 relaxation time, and to analyze whether the spectrum peak was generated by the existence of metabolites in proton MRS is useful for the diagnosis of the intracranial tumors.

Three gluten enriched breads were produced (5% and 15% gluten samples where water was adjusted with farinograph determination, and a 15% sample with the same water amount of the control). The effect of gluten on bread staling (7 days) was evaluated, focussing on texture, amylopectin retrogradation, water status and 1H molecular mobility. The addition of gluten at higher levels (15%) resulted in breads, that retained higher softness, springiness and cohesiveness upon storage. Crumb moisture content was not affected by gluten but at a macromolecular level (DSC) 15% samples showed higher frozen water content. NMR measurements showed a significant effect of gluten on proton T2 relaxation time distributions, revealing a larger presence of protons strongly interacting with water and a more pronounced proton exchange with increasing storage time. The results suggested that, in the presence of gluten, a larger amount of water might be available to plasticize the crumb structure, resulting in a softer product.

The implementation of the HOmodecoupled Band-Selective (HOBS) technique in the conventional Inversion-Recovery and CPMG-based PROJECT experiments is described. The achievement of fully homodecoupled signals allows the distinction of overlapped 1H resonances with small chemical shift differences. It is shown that the corresponding T1 and T2 relaxation times can be individually measured from the resulting singlet lines using conventional exponential curve-fitting methods.