Clinically established thermal therapies like thermo ablative approaches or adjuvant hyperthermia treatment rely on accurate thermal dose information for the evaluation and adaptation of the thermal therapy. Intratumoral temperature measurements have been correlated successfully with clinical endpoints. Magnetic resonance imaging is the most suitable technique for non-invasive thermometry avoiding complications related to invasive temperature measurements. Since the advent of MR thermometry two decades ago, numerous MR thermometry techniques have been developed continuously increasing accuracy and robustness for in vivo applications. While this progress was primarily focused on relative temperature mapping, current and future efforts will likely close the gap towards quantitative temperature readings. These efforts are essential to benchmark thermal therapy efficiency, understand temperature related biophysical and physiological processes and to use these insights to set new landmarks for diagnostic and therapeutic applications. With that in mind, this review summarizes and discusses advances in MR thermometry providing practical considerations, pitfalls and technical obstacles constraining temperature measurement accuracy, spatial and temporal resolution in vivo. Established approaches and current trends in thermal therapy hardware are surveyed with respect to potential benefits for MR thermometry.3

The 16-channel bow tie antenna transceiver array supports accelerated and high spatial resolution cardiac MRI. The array is compatible with multichannel transmission and provides a technological basis for future clinical assessment of parallel transmission techniques at 7.0 Tesla. Magn Reson Med 75:2553-2565, 2016. © 2015 Wiley Periodicals, Inc.

The modular 32-channel transceiver cardiac array supports accelerated and high spatial resolution cardiac MRI. The array is compatible with multichannel transmission and provides a technological basis for future clinical assessment of parallel transmission techniques at 7.0T.

BackgroundGlioblastoma multiforme is the most common and most aggressive malign brain tumor. The 5-year survival rate after tumor resection and adjuvant chemoradiation is only 10 %, with almost all recurrences occurring in the initially treated site. Attempts to improve local control using a higher radiation dose were not successful so that alternative additive treatments are urgently needed. Given the strong rationale for hyperthermia as part of a multimodal treatment for patients with glioblastoma, non-invasive radio frequency (RF) hyperthermia might significantly improve treatment results.MethodsA non-invasive applicator was constructed utilizing the magnetic resonance (MR) spin excitation frequency for controlled RF hyperthermia and MR imaging in an integrated system, which we refer to as thermal MR. Applicator designs at RF frequencies 300 MHz, 500 MHz and 1GHz were investigated and examined for absolute applicable thermal dose and temperature hotspot size. Electromagnetic field (EMF) and temperature simulations were performed in human voxel models. RF heating experiments were conducted at 300 MHz and 500 MHz to characterize the applicator performance and validate the simulations.ResultsThe feasibility of thermal MR was demonstrated at 7.0 T. The temperature could be increased by ~11 °C in 3 min in the center of a head sized phantom. Modification of the RF phases allowed steering of a temperature hotspot to a deliberately selected location. RF heating was monitored using the integrated system for MR thermometry and high spatial resolution MRI. EMF and thermal simulations demonstrated that local RF hyperthermia using the integrated system is feasible to reach a maximum temperature in the center of the human brain of 46.8 °C after 3 min of RF heating while surface temperatures stayed below 41 °C. Using higher RF frequencies reduces the size of the temperature hotspot significantly.ConclusionThe opportunities and capabilities of thermal magnetic resonance for RF hyperthermia interventions of intracranial lesions are intriguing. Employing such systems as an alternative additive treatment for glioblastoma multiforme might be able to improve local control by “fighting fire with fire”. Interventions are not limited to the human brain and might include temperature driven targeted drug and MR contrast agent delivery and help to understand temperature dependent bio- and physiological processes in-vivo.

Objective: To document and review advances and groundbreaking progress in cardiac and body magnetic resonance (MR) at ultrahigh fields (UHF, B0≥7.0 T) with the goal to attract talent, clinical adopters, collaborations and resources to the biomedical and diagnostic imaging communities. Methods Short abstractThis work documents and reviews advances and progress in cardiac and body magnetic resonance technology at ultrahigh fields and its application in forefront research and in early clinical applications. The achievements of ultrahigh field cardiac and body magnetic resonance are shown to be a powerful motivator and enabler, since the extra speed, signal and imaging capabilities may be invested to overcome the fundamental constraints which continue to hamper traditional cardiac and body magnetic resonance applications at lower magnetic field strengths.p a g e | 7

Our findings suggest that myocardial T2* is related to tissue blood volume fraction. Temporally resolved T2* mapping could be beneficial for myocardial tissue characterization and for understanding cardiac (patho)physiology in vivo. Magn Reson Med 77:2381-2389, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Purpose: Thermal intervention is a potent sensitizer of cells to chemo-and radiotherapy in cancer treatment. Glioblastoma multiforme (GBM) is a potential clinical target, given the cancer's aggressive nature and resistance to current treatment options. The annular phased array (APA) technique employing electromagnetic waves in the radiofrequency (RF) range allows for localized temperature increase in deep seated target volumes (TVs). Reports on clinical applications of the APA technique in the brain are still missing. Ultrahigh field magnetic resonance (MR) employs higher frequencies than conventional MR and has potential to provide focal temperature manipulation, high resolution imaging and noninvasive temperature monitoring using an integrated RF applicator (ThermalMR). This work examines the applicability of RF applicator concepts for ThermalMR of brain tumors at 297 MHz (7.0 Tesla). Methods: Electromagnetic field (EMF) simulations are performed for clinically realistic data based on GBM patients. Two algorithms are used for specific RF energy absorption rate based thermal intervention planning for small and large TVs in the brain, aiming at maximum RF power deposition or RF power uniformity in the TV for 10 RF applicator designs. Results: For both TVs, the power optimization outperformed the uniformity optimization. The best results for the small TV are obtained for the 16 element interleaved RF applicator using an elliptical antenna arrangement with water bolus. The two row elliptical RF applicator yielded the best result for the large TV. Discussion: This work investigates the capacity of ThermalMR to achieve targeted thermal interventions in model systems resembling human brain tissue and brain tumors.

ObjectivesThis study is designed to examine the feasibility of ophthalmic MRI at 7.0 T using a local six-channel transmit/receive radiofrequency (RF) coil array in healthy volunteers and patients with intraocular masses. Materials and MethodsA novel six-element transceiver RF coil array that makes uses of loop elements and that is customized for eye imaging at 7.0 T is proposed. Considerations influencing the RF coil design and the characteristics of the proposed RF coil array are presented. Numerical electro-magnetic field (EMF) simulations were conducted to enhance the RF coil characteristics. Specific absorption rate (SAR) simulations and a thorough assessment of RF power deposition were performed to meet the safety requirements. Phantom experiments were carried out to validate the EMF simulations and to assess the real performance of the proposed transceiver array. Certified approval for clinical studies was provided by a local notified body prior to the in vivo studies. The suitability of the RF coil to image the human eye, optical nerve and orbit was examined in an in vivo feasibility study including (i) 3D gradient echo imaging (3D GRE), (ii) inversion recovery 3D gradient echo (3D IR-GRE) and (iii) 2D T2 weighted fast spin-echo (2D FSE) imaging. For this purpose healthy adult volunteers (n=17, mean age 3411 years) and patients with intraocular masses (uveal melanoma, n=5, mean age 576years) were investigated. ResultsAll subjects tolerated all examinations well with no relevant adverse events. The sixchannel coil array supports high resolution 3D GRE imaging with a spatial resolution as good as (0.2 x 0.2 x 1.0) mm 3 which facilitates the depiction of anatomical details of the eye. Rather uniform signal intensity across the eye was found. A mean signal-to-noise ratio (SNR) of approximately 35 was found for the lens while the vitreous humor showed an SNR of page 3 approximately 30. The lens-vitreous humor contrast-to-noise ratio was 8, which allows good differentiation between the lens and the vitreous compartment. Inversion recovery prepared 3D GRE using a spatial resolution of (0.4 x 0.4 x 1.0 mm) 3 was found to be feasible. T2-weighted 2D FSE imaging with the proposed RF coil afforded a spatial resolution of (0.25 x 0.25 x 0.7 mm) 3 . ConclusionsThis work provides valuable information on the feasibility of ophthalmic MRI at 7.0 T using a dedicated six-channel transceiver coil array that supports the acquisition of high contrast, high spatial resolution images in healthy volunteers and patients with intraocular masses. The results underscore the challenges of ocular imaging at 7.0 T and demonstrate that these issues can be offset by using tailored RF coil hardware. The benefits of such improvements would be in positive alignment with explorations that are designed to examine the potential of MRI for the assessment of spatial arrangements of the eye segments and their masses with the ultimate goal to provide imaging means for guiding treatment decisions in ophthalmological diseases.