Imaging Inflammation - From Whole Body Imaging to Cellular Resolution

Imaging techniques have evolved impressively lately, allowing whole new concepts like multimodal imaging, personal medicine, theranostic therapies, and molecular imaging to increase general awareness of possiblities of imaging to medicine field. Here, we have collected the selected (3D) imaging modalities and evaluated the recent findings on preclinical and clinical inflammation imaging. The focus has been on the feasibility of imaging to aid in inflammation precision medicine, and the key challenges and opportunities of the imaging modalities are presented. Some examples of the current usage in clinics/close to clinics have been brought out as an example. This review evaluates the future prospects of the imaging technologies for clinical applications in precision medicine from the pre-clinical development point of view

Dynamic 3D imaging of contrast medium flow on an interventional C-arm using a pulsed injection protocol

This study investigates a method of time resolved 3D (4D) x-ray imaging of contrast dynamics internal to a vascular structure (e.g. intracranial aneurysm) to enable evaluation of blood flow patterns during an interventional procedure. The proposed method employs repetitive-short-pulse injection of small contrast boluses, rotational x-ray imaging with a C-arm, and retrospectively-gated iterative image reconstruction. Under conditions where the passage of each contrast pulse through a vascular region is repeatable and the C-arm rotation is slow compared to the injection cycle, each flow state (spatial distribution of contrast agent at an instant) is imaged at multiple projection angles. After partitioning the projections by flow state, a sequence of 3D volumes corresponding to different states of contrast passage can be reconstructed. Feasibility was demonstrated in a patient-specific 3D-printed aneurysm phantom with 1 Hz simulated cardiac flow waveform. A custom-built power injector was programmed to produce repetitive 100ms injections of iodinated contrast agent upstream of the aneurysm, synchronized to the mid-diastolic phase of the simulated cardiac cycle (1 Hz, 0.4 mL/pulse, 20 pulses, 8 mL total). An interventional C-arm short-scan was performed with 11.3 s rotation time and 27fps frame rate. Modified PICCS reconstruction was used to generate the 4D images. The temporal evolution of contrast agent in the 4D x-ray images was visually similar to the flow patterns observed in MRI imaging and CFD simulation of the same phantom. 95% of the surface deviations between the 4D aneurysm volume and traditional 3D-DSA aneurysm volume were within -0.02 ± 0.24 mm

Influence of Spatial Resolution and Compressed SENSE Acceleration Factor on Flow Quantification with 4D Flow MRI at 3 Tesla

Four-dimensional (4D) flow MRI allows quantifying flow in blood vessels–non invasively and in vivo. The clinical use of 4D flow MRI in small vessels, however, is hampered by long examination times and limited spatial resolution. Compressed SENSE (CS-SENSE) is a technique that can accelerate 4D flow dramatically. Here, we investigated the effect of spatial resolution and CS acceleration on flow measurements by using 4D flow MRI in small vessels in vitro at 3 T. We compared the flow in silicon tubes (inner diameters of 2, 3, 4, and 5 mm) measured with 4D flow MRI, accelerated with four CS factors (CS = 2.5, 4.5, 6.5, and 13) and three voxel sizes (0.5, 1, and 1.5 mm3) to 2D flow MRI and a flow sensor. Additionally, the velocity field in an aneurysm model acquired with 4D flow MRI was compared to the one simulated with computational fluid dynamics (CFD). A strong correlation was observed between flow sensor, 2D flow MRI, and 4D flow MRI (rho > 0.94). The use of fewer than seven voxels per vessel diameter (nROI) resulted in an overestimation of flow in more than 5% of flow measured with 2D flow MRI. A negative correlation (rho = −0.81) between flow error and nROI were found for CS = 2.5 and 4.5. No statistically significant impact of CS factor on differences in flow rates was observed. However, a trend of increased flow error with increased CS factor was observed. In an aneurysm model, the peak velocity and stagnation zone were detected by CFD and all 4D flow MRI variants. The velocity difference error in the aneurysm sac did not exceed 11% for CS = 4.5 in comparison to CS = 2.5 for all spatial resolutions. Therefore, CS factors from 2.5–4.5 can appear suitable to improve spatial or temporal resolution for accurate quantification of flow rate and velocity. We encourage reporting the number of voxels per vessel diameter to standardize 4D flow MRI protocols

Resveratrol Mitigates Metabolism in Human Microglia Cells

The recognition of the role of microglia cells in neurodegenerative diseases has steadily increased over the past few years. There is growing evidence that the uncontrolled and persisting activation of microglial cells is involved in the progression of diseases such as Alzheimer’s or Parkinson’s disease. The inflammatory activation of microglia cells is often accompanied by a switch in metabolism to higher glucose consumption and aerobic glycolysis. In this study, we investigate the changes induced by the natural antioxidant resveratrol in a human microglia cell line. Resveratrol is renowned for its neuroprotective properties, but little is known about its direct effect on human microglia cells. By analyzing a variety of inflammatory, neuroprotective, and metabolic aspects, resveratrol was observed to reduce inflammasome activity, increase the release of insulin-like growth factor 1, decrease glucose uptake, lower mitochondrial activity, and attenuate cellular metabolism in a 1H NMR-based analysis of whole-cell extracts. To this end, studies were mainly performed by analyzing the effect of exogenous stressors such as lipopolysaccharide or interferon gamma on the metabolic profile of microglial cells. Therefore, this study focuses on changes in metabolism without any exogenous stressors, demonstrating how resveratrol might provide protection from persisting neuroinflammation

sj-docx-1-ine-10.1177_15910199221145985 - Supplemental material for The effect of the size of the new contour neurovascular device for altering intraaneurysmal flow

Supplemental material, sj-docx-1-ine-10.1177_15910199221145985 for The effect of the size of the new contour neurovascular device for altering intraaneurysmal flow by Mariya S Pravdivtseva, Andrey N Pravdivtsev, Sönke Peters, Johannes Hensler, Naomi Larsen, Jan-Bernd Hövener, Olav Jansen and Fritz Wodarg in Interventional Neuroradiology</p