An MRI apparatus includes an imaging data acquiring unit and a blood flow information generating unit. The imaging data acquiring unit acquires imaging data from an imaging region including myocardium, without using a contrast medium, by applying a spatial selective excitation pulse to a region including at least a part of an ascending aorta for distinguishably displaying inflowing blood flowing into the imaging region. The blood flow information generating unit generates blood flow image data based on the imaging data.

Magnetic resonance imaging apparatus and magnetic resonance imaging method

Patient-derived xenografts (PDXs) have emerged as an important platform to elucidate new treatments and biomarkers in oncology. PDX models are used to address clinically relevant questions, including the contribution of tumour heterogeneity to therapeutic responsiveness, the patterns of cancer evolutionary dynamics during tumour progression and under drug pressure, and the mechanisms of resistance to treatment. The ability of PDX models to predict clinical outcomes is being improved through mouse humanization strategies and the implementation of co-clinical trials, within which patients and PDXs reciprocally inform therapeutic decisions. This Opinion article discusses aspects of PDX modelling that are relevant to these questions and highlights the merits of shared PDX resources to advance cancer medicine from the perspective of EurOPDX, an international initiative devoted to PDX-based research.

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Interrogating open issues in cancer precision medicine with patient-derived xenografts

Pros and cons of ultra-high-field MRI/MRS for human application.

MR spectroscopic imaging (MRSI) has become a valuable tool for quantifying metabolic abnormalities in human brain, prostate, breast and other organs. It is used in routine clinical imaging, particularly for cancer assessment, and in clinical research applications. This article describes basic principles of commonly used MRSI data acquisition and analysis methods and their impact on clinical applications. It also highlights technical advances, such as parallel imaging and newer high-speed MRSI approaches that are becoming viable alternatives to conventional MRSI methods. Although the main focus is on (1) H-MRSI, the principles described are applicable to other MR-compatible nuclei. This review of the state-of-the-art in MRSI methodology provides a framework for critically assessing the clinical utility of MRSI and for defining future technical development that is expected to lead to increased clinical use of MRSI. Future technical development will likely focus on ultra-high field MRI scanners, novel hyperpolarized contrast agents using metabolically active compounds, and ultra-fast MRSI techniques because these technologies offer unprecedented sensitivity and specificity for probing tissue metabolic status and dynamics.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/jmri.23945

MR spectroscopic imaging: Principles and recent advances

PURPOSE: Dipole antennas in ultrahigh field MRI have demonstrated advantages over more conventional designs. In this study, the fractionated dipole antenna is presented: a dipole where the legs are split into segments that are interconnected by capacitors or inductors. METHODS: A parameter study has been performed on dipole antenna length using numerical simulations. A subsequent simulation study investigates the optimal intersegment capacitor/inductor value. The resulting optimal design has been constructed and compared to a previous design, the single-side adapted dipole (SSAD) by simulations and measurements. An array of eight elements has been constructed for prostate imaging on four subjects (body mass index 20-27.5) using 8 × 2 kW amplifiers. RESULTS: For prostate imaging at 7T, lowest peak local specific-absorption rate (SAR) levels are achieved if the antenna is 30 cm or longer. A fractionated dipole antenna design with inductors between segments has been chosen to achieve even lower SAR levels and more homogeneous receive sensitivities. CONCLUSION: With the new design, good quality prostate images are acquired. SAR levels are reduced by 41% to 63% in comparison to the SSAD. Coupling levels are moderate (average nearest neighbor: -14.6 dB) for each subject and prostate B1+ levels range from 12 to 18 μT.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/mrm.25596

The fractionated dipole antenna: A new antenna for body imaging at 7 Tesla.

Ultra high field MR imaging (≥7 T) of deeply located targets in the body is facing some radiofrequency-field related challenges: interference patterns, reduced penetration depth, and higher Specific Absorbtion Ratio (SAR) levels. These can be alleviated by redesigning the elements of the transmit or transceive array. This is because at these high excitation field (B1) frequencies, conventional array element designs may have become suboptimal. In this work, an alternative design approach is presented, regarding coil array elements as antennas. Following this approach, the Poynting vector of the element should be oriented towards the imaging target region. The single-side adapted dipole antenna is a novel design that fulfills this requirement. The performance of this design as a transmit coil array element has been characterized by comparison with three other, more conventional designs using finite difference time domain (FDTD) simulations and B measurements on a phantom. Results show that the B level at the deeper regions is higher while maintaining relatively low SAR levels. Also, the B field distribution is more symmetrical and more uniform, promising better image homogeneity. Eight radiative antennas have been combined into a belt-like surface array for prostate imaging. T1-weighted (T1W) and T2-weighted (T2W) volunteer images are presented along with B measurements to demonstrate the improved efficiency. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/mrm.22886

Design of a radiative surface coil array element at 7 T: the single-side adapted dipole antenna.

This study demonstrates the feasibility of the noninvasive determination of important biomarkers of human (breast) tumor metabolism using high-field (7-T) MRI and MRS. (31) P MRSI at this field strength was used to provide a direct method for the in vivo detection and quantification of endogenous biomarkers. These encompass phospholipid metabolism, phosphate energy metabolism and intracellular pH. A double-tuned, dual-element transceiver was designed with focused radiofrequency fields for unilateral breast imaging and spectroscopy tuned for optimized sensitivity at 7 T. T(1) -weighted three-dimensional MRI and (1) H MRS were applied for the localization and quantification of total choline compounds. (31) P MRSI was obtained within 20 min per subject and mapped in three dimensions over the breast with pixel volumes of 10 mL. The feasibility of monitoring in vivo metabolism was demonstrated in two patients with breast cancer during neoadjuvant chemotherapy, validated by ex vivo high-resolution magic angle spinning NMR and compared with data from an age-matched healthy volunteer. Concentrations of total choline down to 0.4 mM could be detected in the human breast in vivo. Levels of adenosine and other nucleoside triphosphates, inorganic phosphate, phosphocholine, phosphoethanolamine and their glycerol diesters detected in glandular tissue, as well as in tumor, were mapped over the entire breast. Altered levels of these compounds were observed in patients compared with an age-matched healthy volunteer; modulation of these levels occurred in breast tumors during neoadjuvant chemotherapy. To our knowledge, this is the first comprehensive MRI and MRS study in patients with breast cancer, which reveals detailed information on the morphology and phospholipid metabolism from volumes as small as 10 mL. This endogenous metabolic information may provide a new method for the noninvasive assessment of prognostic and predictive biomarkers in breast cancer treatment.

31P MRSI and 1H MRS at 7 T: initial results in human breast cancer.

A radio frequency coils array includes a plurality of conductive RF loops (62a, 62b, 62c, 62d, 162a, 162b, 262a, 262b, 362a, 362b, 362c, 462a, 462b, 462c, 562a, 562b) configured to excite or receive magnetic resonance signals, and a plurality of electronics modules (64a, 64b, 64c, 64d, 164a, 164b, 264a, 264b, 364a, 364b, 364c, 464a, 464b, 64c, 564a, 564b) corresponding to the plurality of conductive RF loops. The electronics modules are grouped together in a compact electronics region (66, 166, 266, 366, 466, 66). Each RF coil is operatively connected with a corresponding electronics module. Each electronics module includes at least a pre-amplifier.

Compact and flexible radio frequency coil arrays

An antenna array adapted for magnetic resonance imaging, wherein the antenna array comprises at least one antenna element, wherein each antenna element comprises: -a substrate with a first side and a second side, wherein the substrate comprises a dielectric material, -at least one dipole antenna, wherein the dipole antenna is attached to the second side of the substrate, wherein the dipole antenna comprises a first connection adapted for connecting the dipole antenna to a transmission line.

An antenna array comprising at least one dipole antenna for magnetic resonance imaging

The invention provides for a subject support assembly (125) for a magnetic resonance imaging system (100, 200, 300, 400, 500). The subject support is operable for supporting a subject (118) within an imaging zone (108) of a magnet (104) of the magnetic resonance imaging system. The subject support is operable for supporting at least one radio frequency amplifier (124, 124', 124") outside of the imaging zone. The subject support is operable for supplying DC electrical power to the at least one radio frequency amplifier.

Cecilia Possanzini

Papers

Design of a radiative surface coil array element at 7 T: the single-side adapted dipole antenna.

31P MRSI and 1H MRS at 7 T: initial results in human breast cancer.

Compact and flexible radio frequency coil arrays

An antenna array comprising at least one dipole antenna for magnetic resonance imaging

Magnetic resonance imaging subject support