Abstract:
:In this study we aimed to assess the effects of continuous formalin fixation on diffusion and relaxation metrics of the ex vivo porcine heart at 7 T. Magnetic resonance imaging was performed on eight piglet hearts using a 7 T whole body system. Hearts were measured fresh within 3 hours of cardiac arrest followed by immersion in 10% neutral buffered formalin. T2* and T2 were assessed using a gradient multi-echo and multi-echo spin echo sequence, respectively. A spin echo and a custom stimulated echo sequence were employed to assess diffusion time-dependent changes in metrics of cardiac diffusion tensor imaging. SNR was determined for b = 0 images. Scans were performed for 5 mm thick apical, midcavity and basal slices (in-plane resolution: 1 mm) and repeated 7, 15, 50, 100 and 200 days postfixation. Eigenvalues of the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) decreased significantly (P < 0.05) following fixation. Relative to fresh hearts, FA values 7 and 200 days postfixation were 90% and 80%, while respective relative ADC values at those fixation stages were 78% and 92%. Statistical helix and sheetlet angle distributions as well as respective mean and median values showed no systematic influence of continuous formalin fixation. Similar to changes in the ADC, values for T2 , T2* and SNR dropped initially postfixation. Respective relative values compared with fresh hearts at day 7 were 64%, 79% and 68%, whereas continuous fixation restored T2 , T2* and SNR leading to relative values of 74%, 100%, and 81% at day 200, respectively. Relaxation parameters and diffusion metrics are significantly altered by continuous formalin fixation. The preservation of microstructure metrics following prolonged fixation is a key finding that may enable future studies of ventricular remodeling in cardiac pathologies.
journal_name
NMR Biomedjournal_title
NMR in biomedicineauthors
Lohr D,Terekhov M,Veit F,Schreiber LMdoi
10.1002/nbm.4298subject
Has Abstractpub_date
2020-07-01 00:00:00pages
e4298issue
7eissn
0952-3480issn
1099-1492journal_volume
33pub_type
杂志文章abstract::Glucose metabolism in control and estrogen stimulated rat uteri was investigated using 13C NMR spectroscopy. By employing an NMR adapted perifusion system, and developing protocols and methods based on the application of [1-13C]glucose labeling, it was possible to measure, with a temporal resolution of 10 min, the kin...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1940070503
更新日期:1994-08-01 00:00:00
abstract::In MR elastography, it is common to use an elastic model for the tissue's response in order to interpret the results properly. More complex models, such as viscoelastic, fractional viscoelastic, poroelastic, or poroviscoelastic ones, are also used. These models appear at first sight to be very different, but here it i...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3854
更新日期:2018-10-01 00:00:00
abstract::A novel iodoacetamide label 4-perfluoro-tert-butyl-phenyliodoacetamide (PFP) containing nine fluorine atoms in equivalent positions has been synthesized. It provides a homogeneous 19F NMR resonance line which can be detected with high sensitivity when coupled to proteins. As an example, the sulfhydryl groups of actin ...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1940050605
更新日期:1992-11-01 00:00:00
abstract::Increased pulmonary lactate production is correlated with severity of lung injury and outcome in acute respiratory distress syndrome (ARDS) patients. This study was conducted to investigate the relative contributions of inflammation and hypoxia to the lung's metabolic shift to glycolysis in an experimental animal mode...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.4380
更新日期:2020-11-01 00:00:00
abstract::The physiological status of anesthetized rats greatly influences blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI). Monitoring of physiological parameters, particularly partial pressure of carbon dioxide (pCO(2)) levels in the blood, is therefore an important part in the design and ...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.978
更新日期:2005-11-01 00:00:00
abstract::It is generally accepted that tumour microcirculation, blood flow, oxygen and nutrient supply, tissue pH distribution, and the bioenergetic status--factors which are usually closely linked and which define the so-called metabolic microenvironment--can markedly influence the therapeutic response of malignant tumours to...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.1940050505
更新日期:1992-09-01 00:00:00
abstract::1H MR spectroscopy was used to correlate the metabolite signals in 66 untreated metastatic brain tumors with the results of Gd-DTPA enhanced MRI. Cubic volumes containing brain metastases of lung cancer (n = 17), mammary carcinoma (n = 24), melanoma (n = 12) and those originating from other tumors (n = 13) were examin...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/(SICI)1099-1492(199604)9:2<65::AID-NBM397>
更新日期:1996-04-01 00:00:00
abstract::Chronic pain is a major problem for the individual and for society. Despite a range of drugs being available to treat chronic pain, only inadequate pain relief can be achieved for many patients. There is therefore a need for the development of new analgesic compounds. The assessment of pain depends to date entirely on...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1076
更新日期:2006-10-01 00:00:00
abstract::The combination of hyperpolarized Xe with chemical exchange saturation transfer (Hyper-CEST) is a powerful NMR technique to detect highly dilute concentrations of Xe binding sites using RF saturation pulses. Crucially, that combination of saturation pulse strength and duration that generates the maximal Hyper-CEST eff...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3307
更新日期:2015-06-01 00:00:00
abstract::A study was undertaken to determine if the vascular characteristics measured by dynamic contrast-enhanced magnetic resonance imaging (primarily permeability surface area product and extracellular-extravascular tissue volume fraction) would be beneficial in explaining the inter-lesion metabolic heterogeneity displayed ...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.675
更新日期:2000-12-01 00:00:00
abstract::γ-Aminobutyric acid (GABA) and glutamate (Glu), major neurotransmitters in the brain, are recycled through glutamine (Gln). All three metabolites can be measured by magnetic resonance spectroscopy in vivo, although GABA measurement at 3 T requires an extra editing acquisition, such as Mescher-Garwood point-resolved sp...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3847
更新日期:2018-01-01 00:00:00
abstract::Brain activation studies in humans have shown the dynamic nature of neuronal N-acetylaspartate (NAA) and N-acetylaspartylglutamate (NAAG) based on changes in their MRS signals in response to stimulation. These studies demonstrated that upon visual stimulation there was a focal increase in cerebral blood flow (CBF) and...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3629
更新日期:2016-12-01 00:00:00
abstract::In this work, we report a case study of a stroke model in animals using two methods of quantification of the deviations from Gaussian behaviour: diffusion kurtosis imaging (DKI) and log-normal distribution function imaging (LNDFI). The affected regions were predominantly in grey rather than in white matter. The parame...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.2802
更新日期:2012-11-01 00:00:00
abstract::MR Z-spectroscopy allows enhanced imaging contrast on the basis of saturation transfer between the proton pools of cellular compounds and water, occurring via chemical exchange (chemical exchange saturation transfer, CEST) or dipole-dipole coupling (nuclear Overhauser effect, NOE). In previous studies, signals observe...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3021
更新日期:2013-12-01 00:00:00
abstract::The purpose of the present study was to characterize the metabolic profile of the visual cortex in streptozotocin-induced Type 1 diabetic rats by means of in vivo proton MRS. Several metabolite concentration ratios in the visual cortex were calculated. In addition, postmortem histologic analyses for retinal ganglion c...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3783
更新日期:2017-11-01 00:00:00
abstract::Chemical exchange saturation transfer (CEST) can offer information about protons associated with mobile proteins through the amide proton transfer (APT) effect, which has been shown to discriminate tumor from healthy tissue and, more recently, has been suggested as a prognosticator of response to therapy. Despite this...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.2947
更新日期:2013-10-01 00:00:00
abstract::High-resolution MR imaging (312 microns in plane resolution) and MR spectroscopy (0.36 cm3 nominal voxel) have been performed on human frontal cortex using a 3 in surface coil. Localized proton spectra have been obtained from contiguous 6 x 6 x 10 mm voxels using one-dimensional phase encoding, TR 2000 ms and TE 31 ms...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/(SICI)1099-1492(199610)9:7<297::AID-NBM433
更新日期:1996-10-01 00:00:00
abstract::There has been growing interest in understanding energy metabolism in human embryos generated using assisted reproductive techniques (ART) for improving the overall success rate of the method. Using NMR spectroscopy as a noninvasive tool, we studied human embryo metabolism to identify specific biomarkers to assess the...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.2814
更新日期:2013-01-01 00:00:00
abstract::In this methodological paper I report the stereotactic correlation of different magnetic resonance imaging (MRI) techniques [MR angiography (MRA), MRI, blood bolus tagging (STAR), functional MRI, and high-resolution BOLD venography (HRBV)] in patients with cerebral arterio-venous malformations (AVM) and brain tumors. ...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.714
更新日期:2001-11-01 00:00:00
abstract::One of the hallmarks of diffusion NMR and MRI is its ability to utilize restricted diffusion to probe compartments much smaller than the excited volume or the MRI voxel, respectively, and to extract microstructural information from them. Single-pulsed field gradient (s-PFG) MR methodologies have been employed with gre...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.1550
更新日期:2010-08-01 00:00:00
abstract::(1) H-MRS is regularly applied to determine lipid content in ectopic tissue - mostly skeletal muscle and liver - to investigate physiological and/or pathologic conditions, e.g. insulin resistance. Technical developments also allow non-invasive in vivo assessment of cardiac lipids; however, basic data about methodologi...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3186
更新日期:2014-11-01 00:00:00
abstract::The purpose of this work was to harmonize data acquisition and post-processing of single voxel proton MRS ((1) H-MRS) at 7 T, and to determine metabolite concentrations and the accuracy and reproducibility of metabolite levels in the adult human brain. This study was performed in compliance with local institutional hu...
journal_title:NMR in biomedicine
pub_type: 杂志文章,多中心研究
doi:10.1002/nbm.3252
更新日期:2015-03-01 00:00:00
abstract::The transverse relaxation rates R2 and R2* were measured at 3 T in the substantia nigra of the midbrain of adult normal human controls. The relaxation rate arising from magnetic inhomogeneities, R2', was calculated from the relationship R2* = R2 + R2'. No significant differences were found for any parameters between l...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1940080106
更新日期:1995-02-01 00:00:00
abstract::Given the importance of genetically modified mice in studies of mammalian brain development and human congenital brain diseases, MRI has the potential to provide an efficient in vivo approach for analyzing mutant phenotypes in the early postnatal mouse brain. The combination of reduced tissue contrast at the high magn...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.932
更新日期:2004-12-01 00:00:00
abstract::Electric properties tomography (EPT) derives the patient's electric properties, i.e. conductivity and permittivity, using standard magnetic resonance (MR) systems and standard MR sequences. Thus, EPT does not apply externally mounted electrodes, currents or radiofrequency (RF) probes, as is the case in competing techn...
journal_title:NMR in biomedicine
pub_type: 杂志文章,评审
doi:10.1002/nbm.3729
更新日期:2017-08-01 00:00:00
abstract::T2 relaxation time is a quantitative MRI in vivo surrogate of cerebral tissue damage in multiple sclerosis (MS) patients. Cortical T2 prolongation is a known feature in later disease stages, but has not been demonstrated in the cortical normal appearing gray matter (NAGM) in early MS. This study centers on the quantit...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3486
更新日期:2016-04-01 00:00:00
abstract::Blood flow and phosphorus metabolites have been measured simultaneously in the murine RIF-1 tumour in vivo. Blood flow was measured using the H2 washout technique and 31P NMR spectroscopy was used to measure high energy phosphates, inorganic phosphate and intracellular pH within the tumour. Following NMR and flow meas...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1940030406
更新日期:1990-08-01 00:00:00
abstract::Results of the evaluation of transrectal ultrasound (TRUS) guided needle biopsy of voxels identified as suspicious of malignancy on magnetic resonance spectroscopic imaging (MRSI) in a large cohort of men (n = 83) with abnormal digital rectal examination (DRE) [prostate specific antigen (PSA) 0-4 ng/ml] or PSA less th...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.1083
更新日期:2007-02-01 00:00:00
abstract::We introduce a new protocol to obtain very high-frame-rate cinematographic (Cine) MRI movies of the beating mouse heart within a reasonable measurement time. The method is based on a self-gated accelerated fast low-angle shot (FLASH) acquisition and compressed sensing reconstruction. Key to our approach is that we exp...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.2883
更新日期:2013-04-01 00:00:00
abstract::Quantitative susceptibility mapping (QSM) is a recently developed MRI technique that provides a quantitative measure of tissue magnetic susceptibility. To compute tissue magnetic susceptibilities based on gradient echoes, QSM requires reliable unwrapping of the measured phase images and removal of contributions caused...
journal_title:NMR in biomedicine
pub_type: 杂志文章
doi:10.1002/nbm.3056
更新日期:2014-02-01 00:00:00