MR images can be interpreted to measure tissue parameters correlated with cellulite. Considering that we had only three subjects in each group, the achievements of this pilot study were highly satisfactory. We have shown that the in vivo micro-MR is a technique able to detect the effects of cellulite and gender. This study can be extended for further investigations of drugs and/or medical devices for cellulite treatment.
A review of the literature has shown that in human breast tumours, large signals from phosphomonoesters (PME) and phosphodiesters (PDE) are evident. In serial measurements in 19 patients with breast cancer, a decrease in PME was significantly associated with a stable or responding disease (p = 0.017), and an increase in PME was associated with disease progression. Extract studies have shown PME to comprise of phosphoethanolamine (PEth) and phosphocholine (PCho), with the PEth to PCho ratio ranging from 1.3 to 12. The PCho content of high grade tumours was found to be higher than low grade tumours. In some animal models, changes in PCho have been shown to correlate with indices of cellular proliferation, and spheroid studies have shown a decrease in PCho content in spheroids with smaller growth fractions. A serial study of 25 patients with advanced primary breast tumours undergoing hormone, chemotherapy or radiotherapy treatments, showed that in this heterogenous group there were significant changes in metabolites that were seen during the first 3 weeks (range 2–4 weeks) of treatment, that correlated with volume change over this period, employed here as a measure of response. Changes in PME (p = 0.003), total phosphate (TP) (p = 0.008) and total nucleoside tri‐phosphate (TNTP) (p = 0.02) over 3 (±1) weeks were significantly associated with response, as were the levels of PME (p < 0.001), PDE (p = 0.01), TP (p = 0.001) and TNTP (p = 0.007) at week 3 (±1). PME at week 3 (±1) was also significantly associated with the best volume response to treatment (p = 0.03). A reproducibility analysis of results from the observation of normal breast metabolism in four volunteers showed a mean coefficient of variation of 25%, after correcting for changes resulting from the menstrual cycle. Reproducibility studies in four patients with breast cancer showed a mean coefficient of variation of 33%, with the reproducibility being better in patients measured on different days (difference in TP was −6%) compared with those measured on the same day (difference in TP was −29%). © 1998 John Wiley & Sons, Ltd.
Conventionally, MR images are formed by applying gradients to the main static magnetic field (B 0 ). However, the B 0 gradient equipment is expensive, power-hungry, complex, and noisy and can induce eddy currents in nearby conducting structures, including the patient. Here, we describe a new silent, B 0 gradient-free MRI principle, Transmit Array Spatial Encoding (TRASE), based on phase gradients of the radio-frequency (RF) field. RF phase gradients offer a new method of k-space traversal. Echo trains using at least two different RF phase gradients allow spin phase to accumulate, causing kspace traversal. Two such RF fields provide one-dimensional imaging and three are sufficient for two-dimensional imaging. Since TRASE is a k-space method, analogues of many conventional pulse sequences are possible. Experimental results demonstrate one-dimensional and two-dimensional RF MRI and slice selection using a single-channel, transmit/receive, 0.2 T, permanent magnet, human MR system. The experimentally demonstrated spatial resolution is much higher than that provided by RF receive coil array sensitivity encoding alone but lower than generally achievable with B 0 gradients. MRI relies on the introduction of spatial dependence into the NMR experiment. The conventional form this takes is of audiofrequency-modulated magnetic field gradients in the main static magnetic field (B 0 ) (1-3). This requires the installation of a set of coils around the patient, driven with high-current waveforms to produce three linear B 0 gradients (G x , G y , G z ), which add to the main magnetic field and so modify the resonant frequency, depending on both spatial position (x,y,z) and (t) time like so: f ðx; y; z; tÞ ¼ Àðc=2pÞðB 0 þ xG x ðtÞþ yG y ðtÞ þ zG z ðtÞÞ, where G x ¼ @B z =@x, etc. This imaging approach has proven highly successful but incurs substantial costs and system complexity. Typical B 0 gradient system hardware requirements include waveform generation electronics, high-power amplifiers, filters, cables, and heavy-water-cooled self-shielded gradient coils. The B 0 gradient coils themselves occupy valuable space within the magnet bore. Auxiliary to this primary gradient system equipment are various support systems required on site, including a three-phase power supply and air and water cooling systems for the power electronics and gradient coils. As a result, a large fraction of the purchase, installation, and operation costs incurred by MR systems are due to the B 0 gradient system. The operation of a B 0 gradient system leads to some undesirable consequences. The pulsing of the B 0 gradient coil current within the main magnetic field gives rise to loud acoustic noise and vibration, which can be disturbing for patients and may require safety mitigation measures (4). The production of switched B 0 gradients results in induction of eddy currents in any nearby conductors (including the patient) and may result in image artifacts. B 0 gradient switching rates are limited by regulatory agencies to avoid painful or potentially harmf...
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