Introduction: The most challenging radiofrequency (RF)-related issues at high fields are the inhomogeneous excitation and high RF energy absorption, quantified as specific absorption rate (SAR). The former can lead to image intensity variation and regional signal drop-offs, while the latter raises concerns towards the safe use of high-field system. To date, B1-shimming is one of the most promising techniques to circumvent these issues. However, it has been demonstrated that the number of independently controlled transmit elements necessary for applications at 7 T and above is potentially very large [1]. Massive parallel transmit arrays face challenges such as shallow RF penetration and difficulties in managing coil-coil couplings. Moreover, increasing the number of coils and individual power amplifiers escalates the operational cost and system complexity. Herein, we propose using a low channel-count rotating RF coil array [2, 3] to perform B1shimming, while the maximum 10-gram averaged SAR is strictly controlled.

This study explores the performance of a novel hybrid technology, in which the recently introduced rotating RF coil (RRFC) was combined with the principles of Parallel Imaging (PI) to improve the quality and speed of magnetic resonance (MR) images. To evaluate the system, a low-density naturally-decoupled 4-channel rotating radiofrequency coil array (RRFCA) was modelled and investigated. The traditional SENSitivity Encoding (SENSE) reconstruction method and the means of calculating the geometry factor distribution (g map) were adapted to take into account the transient sensitivity encoding. It was found from simulations at 3T that, continuous rotating motion considerably enhanced the coil sensitivity encoding capability, making higher reduction factors in scan time possible. The sensitivity encoding capability can be further improved by choosing an optimal speed of array rotation. Compared to traditional phased-array coils (PACs) with twice as many coil elements, the RRFCA demonstrated clear advantages in terms of quality of reconstruction and superior noise behaviour in all the cases investigated in this initial study.

A new 2 T 3‐element orthogonal knee coil array based on the three‐dimensional orthogonality principle was designed, constructed and used in a series of pilot magnetic resonance imaging (MRI) studies on a standardized phantom, and human and pig knees. The coil elements within this new coil array are positioned orthogonal to one another allowing problematic mutual coupling effects to be minimized without the use of any passive mutual decoupling schemes. The proposed method is appropriate for the design of transmit, receive and/or transceive radiofrequency (RF) coil arrays for applications in animal/human MRI and spectroscopic studies. Experimental results demonstrated that the 3‐element orthogonal knee coil array could be angled arbitrarily, including at 90°, relative to the main static magnetic field (B0) whilst maintaining normal operation with minimal loss of efficiency and functionality. Initial trials with a pig knee specimen further showed that the greatest signal intensity in the patellar ligament (parallel collagen fibres) was observed when the orthogonal knee coil array and the pig knee specimen were angled at ~55° to B0, which may have potential uses in magic angle MR applications. Copyright © 2011 John Wiley & Sons, Ltd.

In magnetic induction tomography (MIT), an array of excitation coils is typically used to apply time-varying magnetic fields to induce eddy currents in the material to be studied. The magnetic fields from the eddy currents are then detected by an array of sensing coils to form an image of passive electromagnetic properties (i.e. conductivity, permittivity and permeability). Increasing the number of transmitters and receivers can provide a better image quality at the expense of a larger and more expensive MIT system. Instead of increasing the number of coils, this study investigates the possibility of rotating a single transmit–receive coil to image the electrical properties of the sample, by emulating an array of 200 transmit–receive coils by time-division multiplexing. Engineering details on the electromechanical design and development of a rotating MIT system are presented. The experimental results indicate that representative images of conductive samples can be obtained at 5 MHz by rotating a single transmit–receive coil.

The establishment of inalienable Muslim endowments (pl. awqaf; sing. waqf) in Bosnia and Herzegovina goes back to the days of the Ottoman occupation of the region in 1463. This article explains their establishment and development together with their institutions with reference to the fifteenth and sixteenth centuries when some of the most famous awqaf emerged. The great period for awqaf came to an end with the Austria-Hungarian takeover in 1878. The author argues that since then the institution of waqf in Bosnia and Herzegovina was subject to injustice, hostility, and devastation from the various regimes that have ruled the country. He explains the deteriorating position of waqf property through the periods of the Kingdom of Yugoslavia and the unlawful confiscation and nationalisation of waqf property and the ultimate complete abolition of the institution of waqf under the communist and socialist regime. This situation lasted until the independence of Bosnia and Herzegovina in 1992 when the Council of the Islamic Community of Bosnia and Herzegovina established the Waqf Directorate. The author also evaluates the legal applications of the restitution claims made by religious communities for the property which was unlawfully confiscated through various legislative mechanisms during and after the communist regime. The ways to safeguard and protect waqf property will be examined as well.

While recent studies have shown that rotating a single radio-frequency (RF) coil during the acquisition of magnetic resonance (MR) images provides a number of hardware advantages (i.e., requires only one RF channel, avoids coil-coil coupling and facilitates large-scale multinuclear imaging), they did not describe in detail how to build a rotating RF coil system. This paper presents detailed engineering information on the electromechanical design and construction of a MR-compatible RRFC system for human head imaging at 2 T. A custom-made (bladeless) pneumatic Tesla turbine was used to rotate the RF coil at a constant velocity, while an infrared optical encoder measured the selected frequency of rotation. Once the rotating structure was mechanically balanced and the compressed air supply suitably regulated, the maximum frequency of rotation measured ~14.5 Hz with a 2.4% frequency variation over time. MR images of a water phantom and human head were obtained using the rotating RF head coil system.

Introduction: Eddy currents are invoked when the time-varying magnetic fields produced by the gradient coils interact with the surrounding conducting structures of the MRI scanner including RF coils. These currents in turn produces acoustic noise, power heating, magnetic field asymmetries, unpleasant acoustic noise, electronic malfunctioning, frequency shift in the RF coil and imaging artifacts [1]. In this abstract we present a new fast, accurate and efficient eddy current simulation method capable of calculating induced currents in thin (finite thickness) conducting and non-magnetic volumes of arbitrary geometry induced by arbitrary arrangements of gradient coils. We assumed that one of the linear Cartesian dimensions is much smaller than the rest and that the volume is divided in thin layers along the smallest Cartesian dimension. This novel method has been experimentally validated using a z-gradient coil and its performance tested against COMSOL and the Fourier Network method (FNM) [2]. We present an example to demonstrate the capabilities of the method in terms of predicting the induced currents, power losses and pre-emphasis simulations using the excited eigenvalue corresponding to the surrounding structure. The method is accurate and fast enough to be performed in a laptop (Intel core(TM) i7 CPU) 8 GB RAM. Method: We assumed a thin but finite thickness, smooth, non-magnetic and conducting domain of arbitrary shape is immerse in a time-varying magnetic field produced by a known current source Js(r,t) of arbitrary geometry. The displacement current is much smaller than the conduction current at the given frequency ω=2πf where f is given in Hz. The domain is divided along the smallest dimension into N layers of thickness h, where h is much smaller than the skin depth δ [2]. Each surface is approximated to a connected set of discrete mesh of plane triangles and the surface current density Ji(r,t) is represented as a finite set of linear basis functions [3]. The Stokes theorem holds in each thin layer and no current flows through the boundaries containing each layer; hence that the layers are inductively coupled but resistively decoupled. The boundary conditions and the edges of the domain are enforced to satisfy the continuity equation. The differential form of the diffusion equation is solved for time-harmonic or transient solution when the coil is driven with an arbitrary current pulse s(t):

Recent research suggests that diffusion-weighted (DW) MRI, and in particular the apparent diffusion coefficient (ADC), can be used to improve the sensitivity and specificity of dynamic contrast-enhanced (DCE) MRI for the detection of breast cancer. However, to date the methods proposed for determining a representative ADC value for a suspicious lesion are highly varied. One approach is to compute the mean ADC value over the entire lesion to obtain a representative ADC value. Another is to compute the mean ADC value within one or more regions of interest (ROIs) defined on the suspicious lesion. The earliest examples of this approach involve manually defining ROIs of hypointensity to be as large as possible, but constrained within the lesion, and such that areas of necrosis are avoided in large lesions. More recent examples of this approach involve placing one or more smaller ROIs of hypointensity within a suspicious lesion and computing, for example, the global minimum [1] or mean [2]. This latter approach appears to provide better discrimination between benign and malignant lesions. Nevertheless to date there does not exist a well-defined and objective method for defining these ROIs. The problem is complicated by the typically low signal-to-noise ratio in the DW images. We propose an automated method based on the converging squares algorithm [3], which is a multiscale minimum finding technique with inherent robustness to noise. We also present an evaluation of the method, using routine clinical data, for computing a representative ADC value for discriminating benign and malignant lesions. The method is also compared to ensemble averaging of ADC values over the entire lesion and the selection of the global minimum ADC value.

In this work, we presented a method to optimise the k-space sampling scheme for CS-MRI. The problem was simplified by treating the variable density functions in parts, and optimising the weighting factors with GA. A 2D brain and a 3D apple MRI image reconstruction illustrates an improved imaging quality with this method.

This research will discuss the attitude of some of the European countries towards Islamic banking and finance. The definition of “Islamic bank” is not compatible with the definition of “Credit institution” stated in the EU Directive 2006/48. The research will explore other alternative ways for Islamic banks to be registered as credit institutions in the EU countries and obstacles that they could face. A special attention will be given to the UK’s approach to Islamic banking industry as the UK is one of the leading Islamic financial hubs in Europe. In reference to the UK, the research will analyze some of the decided cases which have shaped and determined the way forward for Islamic banking industry in Europe. The research will also discuss the possibility of English courts referring to the principles of Islamic law in deciding the Islamic banking cases. In addition to that, the prospects and obstacles for future development of Islamic banking in Germany and France will be briefly discussed.

Introduction: The rotating radiofrequency coil (RRFC) is a novel MR imaging modality, wherein a RF coil moves about the subject to transmit RF wave and receive MR signals [1-2]. Recent studies have demonstrated that, by increasing the velocity of rotation and the signal sampling rate, the RRFC approach can theoretically accelerate the image acquisition with large reduction factors (R), whilst it only demonstrated R=2 in experiment. In order to further reduce the scan time in a practical manner, the RRFC concept has been combined with a 4-element coil array configuration to form the rotating radiofrequency coil array (RRFCA) [3] with a constant angular velocity. By strategically choosing the rotating velocity and imaging parameters (e.g, TR and TE), good performance with large acceleration has been demonstrated [3]. The system matrix of RRFCA is however more complex than that of stationary array, which leads to longer reconstruction times. Here we propose an alternative approach of imaging acceleration with RRFCA. In this new approach, the RRFCA revolves around the subject in a stepping fashion instead of having a constant angular velocity. RRFCA acquires a new position (typically a few degrees away) between two adjacent acquisition times (TACQ) and stays stationary within each TACQ. Please refer to abstract “Highly Accelerated Parallel Imaging using Rotating Radiofrequency Coil Array at 7T” (3916) for more details. Similar to the fastmode [1-3], a large number of sensitivity profiles can be employed for image encoding compared with conventional stationary phased-array coils (PACs). However, the stepping-mode is advantageous in that it is easier to control and the image reconstruction is more efficient without the complication of time-varying sensitivity. In this paper, a fast hybrid image reconstruction strategy is described to further improve the efficiency and accuracy of accelerated image reconstruction with RRFCA. Method: It has been demonstrated that parallel image reconstruction can be achieved with an iterative approach [4], which is suitable for solving simultaneous linear equations with a large number of unknowns. However, it is also known that a good initial estimate of the solution is critical to the solution time and quality. Due to the rotating movement, k-space data are encoded with different sensitivities, and hence the fast initial estimate cannot be realised by zero-padding inverse Fourier transform (IFT) [5]. The aim of this work is to provide fast and accurate initial estimate in a feasible way for the iterative reconstruction framework of RRFCA. The forward MR signal encoding process with a RF receiver is shown in Eq. (1), where m is the k-space samples and ρ is the proton density to be solved. As shown in Eq. (2), W is the combined Fourier (F) and sensitivity (S) encoding matrix; k (k = 1, 2, ..., K) and r (r = 1, 2, ... R) are indices of the k-space samples (m) and the spatial domain proton density distribution (ρ), respectively. Since the sensitivity encoding is identical for each line of W matrix (in Eq. (2), S has no k index), the identical S can be extracted from W and dot multiplied to ρ vector, as shown in Eq. (3). A simple derivation arrives at Eq. (4), with the element of matrix R described in Eq. (5). In essence, Eq. (4) represents an efficient means of recovering image from k-space samples. The reconstruction matrix R consists of inverse Fourier matrix (F), which is readily calculated, followed by the dot-dividing the columns of coil sensitivity. This method has the potential to introduce singularities in the matrix R, by dividing a sufficient small sensitivity S(r). However, such errors can be partly corrected by (a): replacing dividing sensitivity operation to the quotient between conjugate sensitivity and sensitivity modulus; (b) jointly solving Eq. (4) obtained from an array of receiver coils. Eq. (4) and (5) can be easily adapted for RRFCA reconstruction, by taking into account the varying sensitivity profiles for each TACQ. For RRFCA, the reconstruction matrix Rn for the n-th coil element (n = 1, 2 ... N) is shown in Eq.(6). Sn(r,t) is the sensitivity profile at the r-th location produced by the n-th element at time t (t = 1, 2 ... Y, where Y is the number of phase encoding lines). The complete image from all receive channels can be combined with a sum-of-squares (SOS) approach. Results and Discussions: Fig. 1 demonstrates the reconstruction results with simulated data when RRFC and RRFCA were used in signal sampling. Compared with the result of direct inverse Fourier transform (top middle), the fast estimation (bottom left) has a dramatic improvement. It successfully removed most ghost artefacts, by accounting for the time-varying sensitivity in the reconstruction process. The remaining artefacts can be attributed to the loss of orthogonality in the reconstruction matrix. When using the fast estimation as the initial solution, the iterative conjugate gradient method produced an excellent image (top right). However, slight ghosting (red box) can still be observed. This may be owing to the relatively small coil size (35 ̊ open angle) and limited penetration. The fast estimation method was also studied when more rotating elements were introduced. The recovered images are shown in the bottom row, when the number of coils (N) = 2 and 4. The quality of the fast estimation was significantly improved, by eliminating ghosting artefacts and reducing intensity non-uniformity. The acceleration study with multiple coils was performed. As shown in Fig.2, the fast estimation with N = 4 has higher quality, despite the higher reduction factor, and better initial estimation also leads to a superior final image reconstruction. From Fig.3, it is clear that increasing the number of rotating elements can significantly improve the image quality. In terms of reconstruction time, with the help of initial image, a rotating array (4 elements) can reconstruct the image 6.8x faster (i.e. about 28 seconds) on the same commutating platform. Conclusion: A hybrid approach for image reconstruction with RRFCA working in stepping-mode was introduced. Excellent image reconstruction was presented with 4 coil elements at reduction factor of 4 in well less than a minute on a desktop computer, which illustrates the superior encoding capability of RRFCA and the efficiency of the proposed image reconstruction method. In the future, the encoding capability of RRFCA in RF transmission will be studied. References: [1] A.Trakic, et al, Concepts in Magn Reson Part B, vol. 35B, 2009 [2] A.Trakic, et al, Journal of Magn Reson,vol 201,2009. [3] M. Li et al, 1117, IEEE EMBC 2012 [4] K. Pruessmann, et al, Magn Reson in Med, vol46, 1999. [5] K. Pruessmann, et al, Magn Reson in Med, vol46, 2001. Fig.1 The image reconstruction simulation with fast estimation method.

This research paper seeks to highlight the importance of the Shariah Advisory Council of the Central Bank of Malaysia (SAC) in the determination of SharENah issues in adjudicating Islamic banking disputes. Effective resolution of Islamic banking disputes requires the adjudication of both civil and Islamic law issues raised by the parties. Civil courts are well equipped only to adjudicate civil law issues whereas they lack competency to determine issues of SharENah compliance or non-compliance. In Malaysia, an attempt has been made to address the problem by the enactment of certain amendments in the Central Bank of Malaysia Act 1958 and subsequently enacting new provisions in the Central Bank of Malaysia Act 2009. The new provision makes it compulsory for the civil courts and arbitrators to refer SharENah issues to the SAC for determination. Even though challenges are being made against the provision, including on constitutional grounds, the provision seems to be working: to date, courts and arbitrators have already referred such issues to the SAC, and answers have been given and acted upon. The article proposes this model as a viable solution that could be adopted by other countries wishing to introduce or develop Islamic finance.

In high-field clinical MRI, the RF electromagnetic fields within the biological sample become extremely complex, posing substantial challenge in homogeneous excitation and controlled energy deposition. In this study, we demonstrate a novel B1 shimming technique based on a mechanically rotating RF coil and an iterative optimization. Numerical studies show that the new approach can effectively tailor the transmit B1 field and mitigate the tissue heating issue in high-field MRI.