Cancer is among the leading causes of death worldwide. In recent years, many cancer-associated biomarkers have been identified that are used for cancer diagnosis, prognosis, screening, and early detection, as well as for predicting and monitoring carcinogenesis and therapeutic effectiveness. Phosphatidylserine (PS) is a negatively charged phospholipid which is predominantly located in the inner leaflet of the cell membrane. In many cancer cells, PS externalizes to the outer cell membrane, a process regulated by calcium-dependent flippases and scramblases. Saposin C coupled with dioleoylphosphatidylserine (SapC-DOPS) nanovesicle (BXQ-350) and bavituximab, (Tarvacin, human–mouse chimeric monoclonal antibodies) are cell surface PS-targeting drugs being tested in clinical trial for treating a variety of cancers. Additionally, a number of other PS-selective agents have been used to trigger cytotoxicity in tumor-associated endothelial cells or cancer cells in pre-clinical studies. Recent studies have demonstrated that upregulation of surface PS exposure by chemodrugs, radiation, and external electric fields can be used as a novel approach to sensitize cancer cells to PS-targeting anticancer drugs. The objectives of this review are to provide an overview of a unique dual-role of PS as a biomarker/target for cancer imaging and therapy, and to discuss PS-based anticancer strategies that are currently under active development.

This work demonstrates the first whole brain “high spatial resolution” ⁷Li MR spectroscopy imaging in bipolar disorder subjects. The in vivo quantification is validated by a phantom containing 5 mM lithium salt using the identical radiofrequency sequence and imaging protocol. This study is the first demonstration of the ⁷Li distribution in the brain of bipolar disorder patients on lithium therapy using a 3D MR spectroscopy imaging approach. The results show that brain lithium level is strongly correlated with serum lithium concentration. The brain‐to‐serum lithium ratios for the average brain and the local maximum were 0.39 ± 0.08 (r = 0.93) and 0.92 ± 0.16 (r = 0.90), respectively. The lithium distribution is found to be nonuniform throughout the brain for all patients, which is somewhat unexpected and highly intriguing. This uneven distribution is more evident in subjects at a higher therapeutic serum lithium level. This finding may suggest that lithium targets specific brain tissues and/or certain enzymatic and macromolecular sites that are associated with therapeutic effect. Further investigations of bipolar disorder patients on lithium therapy using 3D ⁷Li MR spectroscopy imaging are warranted. Magn Reson Med, 2012.

The desire to quantitatively discriminate the extra- and intracellular tissue ¹ H₂ O MR signals has gone hand-in-hand with the continual, historic increase in MRI instrument magnetic field strength [B₀ ]. However, recent studies have indicated extremely valuable, novel metabolic information can be readily accessible at ultra-low B₀ . The two signals can be distinguished, and the homeostatic activity of the cell membrane sodium/potassium pump (Na⁺ ,K⁺ ,ATPase) detected. The mechanism allowing ¹ H₂ O MRI to do this is the newly discovered active transmembrane water cycling (AWC) phenomenon, which we found using paramagnetic extracellular contrast agents at clinical B₀ values. AWC is important because Na⁺ ,K⁺ ,ATPase can be considered biology's most vital enzyme, and its in vivo steady-state activity has not before been measurable, let alone amenable to mapping with high spatial resolution. Recent reports indicate AWC correlates with neuronal firing rate, with malignant tumor metastatic potential, and inversely with cellular reducing equivalent fraction. We wish to systematize the ways AWC can be precisely measured. We present a theoretical longitudinal relaxation analysis of considerable scope: it spans the low- and high-field situations. We show the NMR shutter-speed organizing principle is pivotal in understanding how trans-membrane steady-state water exchange kinetics are manifest throughout the range. Our findings illuminate an aspect, apparent population inversion, which is crucial in understanding ultra-low field results. Without an appreciation of apparent population inversion, significant misinterpretations of future data are likely. These could have unfortunate diagnostic consequences.

Purpose: To quantify the acoustic noise characteristics of a 4 Tesla MRI scanner, and determine the effects of structural acoustics and gradient pulse excitations on the sound field so that feasible noise control measures can be developed.Materials and Methods: Acoustic noise emissions were measured in the ear and mouth locations of a typical adult. The sound pressure measurements were acquired simultaneously with the electrical current signals of the gradient pulses. Two forms of gradient waveforms (impulsive and operating pulses) were studied.Results: The sound pressure levels (SPLs) emitted by the MRI scanner operating in echo‐planar imaging (EPI) mode were in the range of 120–130 decibels. Three types of sound pressure responses were observed in the EPI sequences: 1) harmonic, 2) nonharmonic, and 3) broadband. The frequency‐encoding gradient pulses were the most dominant and produced generally odd‐number harmonics and nonharmonics. The phase‐encoding gradient pulses generated mostly even‐number harmonics, and the slice‐selection gradient pulses produced primarily a broadband spectrum.Conclusion: The operating condition acoustic spectrum can be predicted from the magnet‐structural acoustic transfer functions, which are independent of imaging sequences. This finding is encouraging because it shows that it is possible to treat such noises with an active noise control application. J. Magn. Reson. Imaging 2006.

Purpose: To evaluate the effectiveness of the proposed active noise control (ANC) system for the reduction of the acoustic noise emission generated by a 4 T MRI scanner during operation and to assess the feasibility of developing an ANC device that can be deployed in situ.Materials and Methods: Three typical scanning sequences, EPI (echo planar imaging), GEMS (gradient echo multislice), and MDEFT (modified driven equilibrium Fourier transform), were used for evaluating the performance of the ANC system, which was composed of a magnetic compatible headset and a multiple reference feedforward filtered‐x least mean square controller.Results: The greatest reduction, about 55 dB, was achieved at the harmonic at a frequency of 1.3 kHz in the GEMS case. Approximately 21 dB and 30 dBA overall reduction was achieved for GEMS noise across the entire audible frequency range. For the MDEFT sequence, the control system achieved 14 dB and 14 dBA overall reduction in the audible frequency range, while 13 dB and 14 dBA reduction was obtained for the EPI case.Conclusion: The result is highly encouraging because it shows great potential for treating magnetic resonance imaging noise with an ANC application during real‐time scanning. J. Magn. Reson. Imaging 2011;.