Assessment of spectral ghost artifacts in echo-planar spectroscopic micro-imaging with flyback readout.

In this work, echo-planar spectroscopic imaging (EPSI) with flyback readout gradient-echo train was implemented in a preclinical MR scanner. The aim of this study is to visualize and quantify the ghost spectral lines produced by two, three and four interleaved echo trains with different amplitudes of the readout gradients, and to investigate the feasibility of the flyback data acquisition in micro-imaging of small animals. Applied multi-slice EPSI sequence utilizes asymmetric gradient-echo train that combines the shortest possible rewind gradients with readout gradients.

The influence of anterior cingulate GABA+ and glutamate on emotion regulation and reactivity in adolescents and adults.

During adolescence, emotion regulation and reactivity are still developing and are in many ways qualitatively different from adulthood. However, the neurobiological processes underpinning these differences remain poorly understood, including the role of maturing neurotransmitter systems. We combined magnetic resonance spectroscopy in the dorsal anterior cingulate cortex (dACC) and self-reported emotion regulation and reactivity in a sample of typically developed adolescents (n = 37; 13-16 years) and adults (n = 39; 30-40 years), and found that adolescents had higher levels of glutamate to total creatine (tCr) ratio in the dACC than adults.

Decreased renal perfusion during acute kidney injury in critical COVID-19 assessed by magnetic resonance imaging: a prospective case control study.

Background: Renal hypoperfusion has been suggested to contribute to the development of acute kidney injury (AKI) in critical COVID-19. However, limited data exist to support this. We aim to investigate the differences in renal perfusion, oxygenation and water diffusion using multiparametric magnetic resonance imaging in critically ill COVID-19 patients with and without AKI.

Pupil dilation during negative prediction errors is related to brain choline concentration and depressive symptoms in adolescents.

Depressive symptoms are associated with altered pupillary responses during learning and reward prediction as well as with changes in neurometabolite levels, including brain concentrations of choline, glutamate and gamma-aminobutyric acid (GABA). However, the full link between depressive symptoms, reward-learning-related pupillary responses and neurometabolites is yet to be established as these constructs have not been assessed in the same individuals. The present pilot study, investigated these relations in a sample of 24 adolescents aged 13 years.

Chronic cerebral blood flow alterations in traumatic brain injury and sports-related concussions.

Primary Objective: Traumatic brain injury (TBI) and sports-related concussion (SRC) may result in chronic functional and neuroanatomical changes. We tested the hypothesis that neuroimaging findings (cerebral blood flow (CBF), cortical thickness, and H-magnetic resonance (MR) spectroscopy (MRS)) were associated to cognitive function, TBI severity, and sex.

Research Design: Eleven controls, 12 athletes symptomatic following ≥3SRCs and 6 patients with moderate-severe TBI underwent MR scanning for evaluation of cortical thickness, brain metabolites (MRS), and CBF using pseudo-continuous arterial spin labeling (ASL).

Phosphorus MRS of healthy human spleen.

Phosphorus ( P-) MRS in vivo enables detection and quantification of important phosphorus-containing metabolites in biological tissues. P-MRS of the normal spleen is challenging due to the relatively small volume and the larger distance between the spleen and surface coil. However, reference spectra of the healthy spleen are invaluable in studies of splenic malignancies and benign causes of splenomegaly, as well as in the study of its physiology.

Inhibitory and excitatory neurotransmitter systems in depressed and healthy: A positron emission tomography and magnetic resonance spectroscopy study.

The Gamma-aminobutyric acid (GABA) and glutamate (Glu) neurotransmitter systems are implicated in depression. While previous studies found reduced GABA levels, and a tendency towards reduced Glu, using proton (H) magnetic resonance spectroscopy (H-MRS), little is known about GABA receptor availability in depression. Here, the aim was to characterize GABA and Glu-levels in dorsal anterior cingulate cortex (dACC), whole-brain GABA availability, and their relationship in patients with depression compared to healthy controls.

The Use of a Non-Conventional Long-Lived Gallium Radioisotope Ga Improves Imaging Contrast of EGFR Expression in Malignant Tumours Using DFO-ZEGFR:2377 Affibody Molecule.

Epidermal growth factor receptor (EGFR) is overexpressed in many malignancies. EGFR-targeted therapy extends survival of patients with disseminated cancers. Radionuclide molecular imaging of EGFR expression would make EGFR-directed treatment more personalized and therefore more efficient.

GABA quantification in human anterior cingulate cortex.

γ-Aminobutyric acid (GABA) is a primary inhibitory neurotransmitter in the human brain. It has been shown that altered GABA concentration plays an important role in a variety of psychiatric and neurological disorders. The main purpose of this study was to propose a combination of PRESS and MEGA-PRESS acquisitions for absolute GABA quantification and to compare GABA estimations obtained using total choline (tCho), total creatine (tCr), and total N-acetyl aspartate (tNAA) as the internal concentration references with water referenced quantification.

Radiolabelling and positron emission tomography imaging of a high-affinity peptide binder to collagen type 1.

Introduction: Pathological formation of fibrosis, is an important feature in many diseases. Fibrosis in liver and pancreas has been associated to metabolic disease including type 1 and 2 diabetes. The current methods for detecting and diagnosing fibrosis are either invasive, or their sensitivity to detect fibrosis in early stage is limited.

Circadian variation in renal blood flow and kidney function in healthy volunteers monitored with noninvasive magnetic resonance imaging.

Circadian regulation of kidney function is involved in maintaining whole body homeostasis, and dysfunctional circadian rhythm can potentially be involved in disease development. Magnetic resonance imaging (MRI) provides reliable and reproducible repetitive estimates of kidney function noninvasively without the risk of adverse events associated with contrast agents and ionizing radiation. The purpose of this study was to estimate circadian variations in kidney function in healthy human subjects with MRI and to relate the findings to urinary excretions of electrolytes and markers of kidney function.

Synthesis and preclinical evaluation of the CRTH2 antagonist [C]MK-7246 as a novel PET tracer and potential surrogate marker for pancreatic beta-cell mass.

Introduction: MK-7246 is a potent and selective antagonist for chemoattractant receptor-homologous molecule expressed on T2 cells (CRTH2). Within the pancreas CRTH2 is selectively expressed in pancreatic β-cells where it is believed to play a role in insulin release. Reduction in β-cell mass and insufficient insulin secretion in response to elevated blood glucose levels is a hallmark for type 1 and type 2 diabetes.

Pancreatic perfusion and its response to glucose as measured by simultaneous PET/MRI.

Aims: Perfusion of the pancreas and the islets of Langerhans is sensitive to physiological stimuli and is dysregulated in metabolic disease. Pancreatic perfusion can be assessed by both positron emission tomography (PET) and magnetic resonance imaging (MRI), but the methods have not been directly compared or benchmarked against the gold-standard microsphere technique.

Methods: Pigs (n = 4) were examined by [O]HO PET and intravoxel incoherent motion (IVIM) MRI technique simultaneously using a hybrid PET/MRI scanner.

Proton MR spectroscopy of human pancreas allografts.

Objective: To estimate pancreas graft relaxation times and concentrations of total fat, and the intracellular lipids of non-adipose pancreatic cells (NAPC) using proton (H) magnetic resonance spectroscopy (MRS) during cold preservation.

Materials And Methods: Grafts from 11 human donors were investigated. Each pancreas was perfused in situ with histidine-tryptophan-ketoglutarate (HTK) or with University of Wisconsin solution and placed into a transport container.

Multiparametric assessment of renal physiology in healthy volunteers using noninvasive magnetic resonance imaging.

Noninvasive methods of magnetic resonance imaging (MRI) can quantify parameters of kidney function. The main purpose of this study was to determine baseline values of such parameters in healthy volunteers. In 28 healthy volunteers (15 women and 13 men), arterial spin labeling to estimate regional renal perfusion, blood oxygen level-dependent transverse relaxation rate (R*) to estimate oxygenation, and apparent diffusion coefficient (ADC), true diffusion (D), and longitudinal relaxation time (T) to estimate tissue properties were determined bilaterally in the cortex and outer and inner medulla.

Assessment of cerebral perfusion and edema in preeclampsia with intravoxel incoherent motion MRI.

Introduction: Cerebral complications are the main reasons for morbidity and mortality in preeclampsia and eclampsia. As yet, we do not know whether the pathophysiology entails hypo- or hyperperfusion of the brain, or how and when edema emerges, due to the difficulty of examining the cerebral circulation.

Material And Methods: We have used a non-invasive diffusion weighted-magnetic resonance imaging technique, intravoxel incoherent motion, to study cerebral perfusion on the capillary level and cerebral edema in women with preeclampsia (n = 30), normal pregnancy (n = 32), and non-pregnant women (n = 16).

Cerebral Osmolytes and Plasma Osmolality in Pregnancy and Preeclampsia: A Proton Magnetic Resonance Spectroscopy Study.

Background: Cerebral complications contribute substantially to mortality in preeclampsia. Pregnancy calls for extensive maternal adaptations, some associated with increased propensity for seizures, but the pathophysiology behind the eclamptic seizures is not fully understood. Plasma osmolality and sodium levels are lowered in pregnancy.

An Intraprostatic Modified Release Formulation of Antiandrogen 2-Hydroxyflutamide for Localized Prostate Cancer.

Purpose: We investigated the tolerability, safety and antitumor effects of a novel intraprostatic depot formulation of antiandrogen 2-hydroxyflutamide (in NanoZolid®) in men with localized prostate cancer.

Materials And Methods: Two clinical trials, LPC-002 and LPC-003, were performed in a total of 47 men. The formulation was injected transrectally into the prostate under ultrasound guidance.

Multiple breath-hold proton spectroscopy of human liver at 3T: Relaxation times and concentrations of glycogen, choline, and lipids.

Purpose: To evaluate the feasibility of an expiration multiple breath-hold H-MRS technique to measure glycogen (Glycg), choline-containing compounds (CCC), and lipid relaxation times T , T , and their concentrations in normal human liver.

Materials And Methods: Thirty healthy volunteers were recruited. Experiments were performed at 3T.

Cerebral Magnesium Levels in Preeclampsia; A Phosphorus Magnetic Resonance Spectroscopy Study.

Background: Magnesium sulfate (MgSO4) is used as a prophylaxis for eclamptic seizures. The exact mechanism of action is not fully established. We used phosphorus magnetic resonance spectroscopy (31P-MRS) to investigate if cerebral magnesium (Mg2+) levels differ between women with preeclampsia, normal pregnant, and nonpregnant women.

Pre-transplantation P-magnetic resonance spectroscopy for quality assessment of human pancreatic grafts - A feasibility study.

Objective: To investigate the feasibility of using P-MRS for objective non-invasive quality assessment of human pancreas grafts prior to transplantation or islet isolation.

Materials And Methods: Pancreata from 5 human donors, 3 males and 2 females, aged 49-78years, with body mass index (BMI) 22-31kg/m, were included. Pancreata were perfused with histidine-tryptophan-ketoglutarate solution during procurement and stored in hypothermic condition (4°C) for 21-44h.

Quantification of metabolite concentrations in benign and malignant prostate tissues using 3D proton MR spectroscopic imaging.

Purpose: To estimate concentrations of choline (Cho), spermine (Spm), and citrate (Cit) in prostate tissue using 3D proton magnetic resonance spectroscopic imaging (MRSI) with water as an internal concentration reference as well as to assess the relationships between the measured metabolites and also between the metabolites and apparent diffusion coefficient (ADC).

Materials And Methods: Forty-six prostate cancer patients were scanned at 3T. Spectra were acquired with the point-resolved spectroscopy (PRESS) localization technique.

High-resolution echo-planar spectroscopic imaging of the human calf.

Background: This study exploits the speed benefits of echo-planar spectroscopic imaging (EPSI) to acquire lipid spectra of skeletal muscle. The main purpose was to develop a high-resolution EPSI technique for clinical MR scanner, to visualise the bulk magnetic susceptibility (BMS) shifts of extra-myocellular lipid (EMCL) spectral lines, and to investigate the feasibility of this method for the assessment of intra-myocellular (IMCL) lipids.

Methods: The study group consisted of six healthy volunteers.

MR spectroscopy of the prostate at 3T: measurements of relaxation times and quantification of prostate metabolites using water as an internal reference.

Purpose: We performed single-voxel magnetic resonance spectroscopy (MRS) of the human prostate at 3 tesla using a surface coil to measure prostate water, choline (Cho), creatine (Cr), and citrate (Cit) relaxation times T1, T2, and to estimate concentrations of Cho, Cr, and Cit in healthy volunteers.

Methods: In nine of 17 healthy volunteers, we performed experiments to estimate relaxation time, and we used the spectra of the other eight to compute metabolite concentrations. Spectra were processed by LCModel and AMARES (advanced method for accurate, robust, and efficient spectral fitting) algorithms.

OP003. Placental perfusion in normal pregnancy and in early and late preeclampsia: A magnetic resonance imaging study.

Introduction: Placental perfusion is of key interest for the understanding of the pathophysiology of different types of preeclampsia (PE). With magnetic resonance imaging (MRI) perfusion can be estimated non-invasively by calculation of the tissue perfusion fraction from a diffusion weighted sequence (DWI).

Objectives: Our primary aim was to investigate if women with early or late PE have different placental perfusion compared with normal pregnancies.