Rapid functional cardiac imaging after gadolinium injection: Evaluation of a highly accelerated sequence with sparse data sampling and iterative reconstruction.

To generate a patient-friendly, time-efficient cardiac MRI examination protocol, a highly accelerated real-time CINE MR sequence (SSIR) was acquired in the idle time in between contrast injection and late gadolinium enhancement phase. 20 consecutive patients underwent a cardiac MRI examination including a multi-breath-hold sequence as gold standard (Ref) as well as SSIR sequences with (SSIR-BH) and without breath-hold (SSIR-nonBH). SSIR sequences were acquired 4 minutes after gadolinium injection.

Myocardial T-mapping at 3T using saturation-recovery: reference values, precision and comparison with MOLLI.

Background: Myocardial T-mapping recently emerged as a promising quantitative method for non-invasive tissue characterization in numerous cardiomyopathies. Commonly performed with an inversion-recovery (IR) magnetization preparation at 1.5T, the application at 3T has gained due to increased quantification precision.

Deficient fear extinction memory in posttraumatic stress disorder.

Background: Posttraumatic stress disorder (PTSD) might be maintained by deficient extinction memory. We used a cued fear conditioning design with extinction and a post-extinction phase to provoke the return of fear and examined the role of the interplay of amygdala, hippocampus and prefrontal regions.

Methods: We compared 18 PTSD patients with two healthy control groups: 18 trauma-exposed subjects without PTSD (nonPTSD) and 18 healthy controls (HC) without trauma experience.

"One-Stop Shop": Free-Breathing Dynamic Contrast-Enhanced Magnetic Resonance Imaging of the Kidney Using Iterative Reconstruction and Continuous Golden-Angle Radial Sampling.

Aims And Objectives: The purpose of the present study was to evaluate a recently introduced technique for free-breathing dynamic contrast-enhanced renal magnetic resonance imaging (MRI) applying a combination of radial k-space sampling, parallel imaging, and compressed sensing. The technique allows retrospective reconstruction of 2 motion-suppressed sets of images from the same acquisition: one with lower temporal resolution but improved image quality for subjective image analysis, and one with high temporal resolution for quantitative perfusion analysis.

Materials And Methods: In this study, 25 patients underwent a kidney examination, including a prototypical fat-suppressed, golden-angle radial stack-of-stars T1-weighted 3-dimensional spoiled gradient-echo examination (GRASP) performed after contrast agent administration during free breathing.

Comparison of spoiled gradient echo and steady-state free-precession imaging for native myocardial T1 mapping using the slice-interleaved T1 mapping (STONE) sequence.

Cardiac T1 mapping allows non-invasive imaging of interstitial diffuse fibrosis. Myocardial T1 is commonly calculated by voxel-wise fitting of the images acquired using balanced steady-state free precession (SSFP) after an inversion pulse. However, SSFP imaging is sensitive to B1 and B0 imperfection, which may result in additional artifacts.

Black-blood native T mapping: Blood signal suppression for reduced partial voluming in the myocardium.

Purpose: To study the feasibility of black-blood contrast in native T mapping for reduction of partial voluming at the blood-myocardium interface.

Methods: A saturation pulse prepared heart-rate-independent inversion recovery (SAPPHIRE) T mapping sequence was combined with motion-sensitized driven-equilibrium (MSDE) blood suppression for black-blood T mapping at 3 Tesla. Phantom scans were performed to assess the T time accuracy.

Motion-robust cardiac B1+ mapping at 3T using interleaved bloch-siegert shifts.

Purpose: To develop and evaluate a robust motion-insensitive Bloch-Siegert shift based B1+ mapping method in the heart.

Methods: Cardiac Bloch-Siegert B1+ mapping was performed with interleaved positive and negative off-resonance shifts and diastolic spoiled gradient echo imaging in 12 heartbeats. Numerical simulations were performed to study the impact of respiratory motion.

Design of a multimodal (H/Na MR/CT) anthropomorphic thorax phantom.

Objectives: This work proposes a modular, anthropomorphic MR and CT thorax phantom that enables the comparison of experimental studies for quantitative evaluation of deformable, multimodal image registration algorithms and realistic multi-nuclear MR imaging techniques.

Methods: A human thorax phantom was developed with insertable modules representing lung, liver, ribs and additional tracking spheres. The quality of human tissue mimicking characteristics was evaluated for H and Na MR as well as CT imaging.

Renal Denervation in Patients with Resistant Hypertension-Assessment by 3T Renal 23Na-MRI: Preliminary Results.

Background/aim: Renal denervation (RDN) has been considered a promising therapy option for patients suffering from therapy-resistant hypertension. Besides, in blood-pressure regularization, the kidneys play a fundamental role in sodium ((23)Na) homeostasis. This study assesses the effect of RDN on renal (23)Na concentration using (23)Na magnetic resonance imaging (MRI).

Reduced amygdala responsivity during conditioning to trauma-related stimuli in posttraumatic stress disorder.

Exaggerated conditioned fear responses and impaired extinction along with amygdala overactivation have been observed in posttraumatic stress disorder (PTSD). These fear responses might be triggered by cues related to the trauma through higher-order conditioning, where reminders of the trauma may serve as unconditioned stimuli (US) and could maintain the fear response. We compared arousal, valence, and US expectancy ratings and BOLD brain responses using fMRI in 14 traumatized persons with PTSD and 14 without PTSD (NPTSD) and 13 matched healthy controls (HC) in a differential aversive conditioning paradigm.

Gaussian signal relaxation around spin echoes: Implications for precise reversible transverse relaxation quantification of pulmonary tissue at 1.5 and 3 Tesla.

Purpose: To characterize the reversible transverse relaxation in pulmonary tissue and to study the benefit of a quadratic exponential (Gaussian) model over the commonly used linear exponential model for increased quantification precision.

Methods: A point-resolved spectroscopy sequence was used for comprehensive sampling of the relaxation around spin echoes. Measurements were performed in an ex vivo tissue sample and in healthy volunteers at 1.

Multi-class texture analysis in colorectal cancer histology.

Automatic recognition of different tissue types in histological images is an essential part in the digital pathology toolbox. Texture analysis is commonly used to address this problem; mainly in the context of estimating the tumour/stroma ratio on histological samples. However, although histological images typically contain more than two tissue types, only few studies have addressed the multi-class problem.

A novel approach for a 2D/3D image registration routine for medical tool navigation in minimally invasive vascular interventions.

Minimally invasive interventions are frequently aided by 2D projective image guidance. To facilitate the navigation of medical tools within the patient, information from preoperative 3D images can supplement interventional data. This work describes a novel approach to perform a 3D CT data registration to a single interventional native fluoroscopic frame.

Pulsed arterial spin labelling at ultra-high field with a B 1 (+) -optimised adiabatic labelling pulse.

Objective: Arterial spin labelling (ASL) techniques benefit from the increased signal-to-noise ratio and the longer T 1 relaxation times available at ultra-high field. Previous pulsed ASL studies at 7 T concentrated on the superior regions of the brain because of the larger transmit radiofrequency inhomogeneity experienced at ultra-high field that hinders an adequate inversion of the blood bolus when labelling in the neck. Recently, researchers have proposed to overcome this problem with either the use of dielectric pads, through dedicated transmit labelling coils, or special adiabatic inversion pulses.

Region of interest-based versus whole-lung segmentation-based approach for MR lung perfusion quantification in 2-year-old children after congenital diaphragmatic hernia repair.

Objective: With a region of interest (ROI)-based approach 2-year-old children after congenital diaphragmatic hernia (CDH) show reduced MR lung perfusion values on the ipsilateral side compared to the contralateral. This study evaluates whether results can be reproduced by segmentation of whole-lung and whether there are differences between the ROI-based and whole-lung measurements.

Methods: Using dynamic contrast-enhanced (DCE) MRI, pulmonary blood flow (PBF), pulmonary blood volume (PBV) and mean transit time (MTT) were quantified in 30 children after CDH repair.

Quantitative arterial spin labelling perfusion measurements in rat models of renal transplantation and acute kidney injury at 3T.

Objectives: To employ ASL for the measurement of renal cortical perfusion in particular renal disorders typically associated with graft loss and to investigate its potential to detect and differentiate the related functional deterioration i.e., in a setting of acute kidney injury (AKI) as well as in renal grafts showing acute and chronic transplant rejection.

Lung Perfusion MRI After Congenital Diaphragmatic Hernia Repair in 2-Year-Old Children With and Without Extracorporeal Membrane Oxygenation Therapy.

Objective: In severe cases of congenital diaphragmatic hernia (CDH), extracorporeal membrane oxygenation (ECMO) therapy improves survival. Later on, lung morbidity mainly defines development. The purpose of this study was to investigate whether 2-year-old children who need ECMO therapy after delivery have reduced perfusion MRI values as a sign of more severe lung hypoplasia than do children who do not need ECMO.

Desynchronization of Cartesian k-space sampling and periodic motion for improved retrospectively self-gated 3D lung MRI using quasi-random numbers.

Purpose: To demonstrate that desynchronization between Cartesian k-space sampling and periodic motion in free-breathing lung MRI improves the robustness and efficiency of retrospective respiratory self-gating.

Methods: Desynchronization was accomplished by reordering the phase (k ) and partition (k ) encoding of a three-dimensional FLASH sequence according to two-dimensional, quasi-random (QR) numbers. For retrospective respiratory self-gating, the k-space center signal (DC signal) was acquired separately after each encoded k-space line.

Statin Therapy and the Development of Cerebral Amyloid Angiopathy--A Rodent in Vivo Approach.

Background: Cerebral amyloid angiopathy (CAA) is characterized by vascular deposition of amyloid β (Aβ) with a higher incidence of cerebral microbleeds (cMBs) and spontaneous hemorrhage. Since statins are known for their benefit in vascular disease we tested for the effect on CAA.

Methods: APP23-transgenic mice received atorvastatin-supplemented food starting at the age of eight months (n = 13), 12 months (n = 7), and 16 months (n = 6), respectively.

Fast glomerular quantification of whole ex vivo mouse kidneys using Magnetic Resonance Imaging at 9.4 Tesla.

A method to measure total glomerular number (Nglom) in whole mouse kidneys using MRI is presented. The method relies on efficient acquisition times. A 9.

An open source software for analysis of dynamic contrast enhanced magnetic resonance images: UMMPerfusion revisited.

Background: Perfusion imaging has become an important image based tool to derive the physiological information in various applications, like tumor diagnostics and therapy, stroke, (cardio-) vascular diseases, or functional assessment of organs. However, even after 20 years of intense research in this field, perfusion imaging still remains a research tool without a broad clinical usage. One problem is the lack of standardization in technical aspects which have to be considered for successful quantitative evaluation; the second problem is a lack of tools that allow a direct integration into the diagnostic workflow in radiology.

New Colors for Histology: Optimized Bivariate Color Maps Increase Perceptual Contrast in Histological Images.

Background: Accurate evaluation of immunostained histological images is required for reproducible research in many different areas and forms the basis of many clinical decisions. The quality and efficiency of histopathological evaluation is limited by the information content of a histological image, which is primarily encoded as perceivable contrast differences between objects in the image. However, the colors of chromogen and counterstain used for histological samples are not always optimally distinguishable, even under optimal conditions.

F Oximetry with semifluorinated alkanes.

This work examines the variation of longitudinal relaxation rate R1(= 1/T1) of the F-CF-resonance of semifluorinated alkanes (SFAs) with oxygen tension (pO), temperature (T) and pH in vitro. Contrary to their related perfluorocarbons (PFCs), SFA are amphiphilic and facilitate stable emulsions, a prerequisite for clinical use. A linear relationship between R1 and pO was confirmed for the observed SFAs at different temperatures.

Fast three-dimensional inner volume excitations using parallel transmission and optimized k-space trajectories.

Purpose: To design short parallel transmission (pTx) pulses for excitation of arbitrary three-dimensional (3D) magnetization patterns.

Methods: We propose a joint optimization of the pTx radiofrequency (RF) and gradient waveforms for excitation of arbitrary 3D magnetization patterns. Our optimization of the gradient waveforms is based on the parameterization of k-space trajectories (3D shells, stack-of-spirals, and cross) using a small number of shape parameters that are well-suited for optimization.