Hybrid MPI-MRI System for Dual-Modal In Situ Cardiovascular Assessments of Real-Time 3D Blood Flow Quantification-A Pre-Clinical In Vivo Feasibility Investigation.

Non-invasive quantification of functional parameters of the cardiovascular system, in particular the heart, remains very challenging with current imaging techniques. This aspect is mainly due to the fact, that the spatio-temporal resolution of current imaging methods, such as Magnetic Resonance Imaging (MRI) or Positron Emission Tomography (PET), does not offer the desired data repetition rates in the context of real-time data acquisition and thus, can cause artifacts and misinterpretations in accelerated data acquisition approaches. We present a fast non-invasive and quantitative dual-modal in situ cardiovascular assessment using a hybrid imaging system which combines the new imaging modality Magnetic Particle Imaging (MPI) and MRI.

System Characterization of a Highly Integrated Preclinical Hybrid MPI-MRI Scanner.

Magnetic particle imaging (MPI) is a novel tracer-based in vivo imaging modality allowing quantitative measurements of the spatial distributions of superparamagnetic iron oxide (SPIO) nanoparticles in three dimensions (3D) and in real time using electromagnetic fields. However, MPI lacks the detection of morphological information which makes it difficult to unambiguously assign spatial SPIO distributions to actual organ structures. To compensate for this, a preclinical highly integrated hybrid system combining MPI and Magnetic Resonance Imaging (MRI) has been designed and gets characterized in this work.

Structure of the charge separated state P865(+)Q(A)- in the photosynthetic reaction centers of Rhodobacter sphaeroides by quantum beat oscillations and high-field electron paramagnetic resonance: evidence for light-induced Q(A)- reorientation.

The structure of the secondary radical pair, P865(+)Q(A)-, in fully deuterated and Zn-substituted reaction centers (RCs) of the purple bacterium Rhodobacter sphaeroides R-26 has been determined by high-time resolution and high-field electron paramagnetic resonance (EPR). A computer analysis of quantum beat oscillations, observed in a two-dimensional Q-band (34 GHz) EPR experiment, provides the orientation of the various magnetic tensors of P865(+)Q(A)- with respect to a magnetic reference frame. The orientation of the g-tensor of P865(+) in an external reference system is adapted from a single-crystal W-band (95 GHz) EPR study [Klette, R.