Trevor Wade

In vivo magnetic resonance imaging of glucose - initial experience.

A new noninvasive, nonradioactive approach for glucose imaging using spin hyperpolarization technology and stable isotope labeling is presented. A glucose analog labeled with (13)C at all six positions increased the overall hyperpolarized imaging signal; deuteration at all seven directly bonded proton positions prolonged the spin-lattice relaxation time. High-bandwidth (13)C imaging overcame the large glucose carbon chemical shift dispersion. Hyperpolarized glucose images in the live rat showed time-dependent organ distribution patterns. At 8 s after the start of bolus injection, the inferior vena cava was demonstrated at angiographic quality. Distribution of hyperpolarized glucose in the kidneys, vasculature, and heart was demonstrated at 12 and 20 s. The heart-to-vasculature intensity ratio at 20 s suggests myocardial uptake. Cancer imaging, currently performed with (18)F-deoxyglucose positron emission tomography (FDG-PET), warrants further investigation, and glucose imaging could be useful in a vast range of clinical conditions and research fields where the radiation associated with the FDG-PET examination limits its use.

Scan–rescan and intra-observer variability of magnetic resonance imaging of carotid atherosclerosis at 1.5 T and 3.0 T

Carotid atherosclerosis measurements for eight subjects at baseline and 14 +/- 2 days later were examined using 1.5 T and 3.0 T magnetic resonance imaging (MRI). A single observer blinded to field strength, subject and timepoint manually segmented carotid artery wall and lumen boundaries in randomized images in five measurement trials. Mean increases in the signal-to-noise ratios (SNR) for T1-weighted images acquired at 3.0 T compared to 1.5 T were 90% (scan) and 80% (rescan). Despite significantly improved SNR and contrast-to-noise ratios (CNR) for images acquired at 3.0 T, vessel wall volume (VWV) intra-observer variability was not significantly different using coefficients of variation (COV), and intraclass correlation coefficients (ICC). VWV interscan variability and consistency at both field strengths were not statistically different (1.5 T/3.0 T COV = 5.7%/7.8%, R(2) = 0.96 for 1.5 T and R(2) = 0.87 for 3.0 T). A two-way analysis of variance showed a VWV dependence on field strength but not scan timepoint. In addition, a paired t-test showed significant differences in VWV measured at 3.0 T as compared to 1.5 T. These results suggest that although images acquired at 1.5 T have lower SNR and CNR VWV, measurement variability was not significantly different from 3.0 T VWV and that VWV is field-strength dependent which may be an important consideration for longitudinal studies.

Fat fraction bias correction using T1 estimates and flip angle mapping.

To develop a new method of reducing T1 bias in proton density fat fraction (PDFF) measured with iterative decomposition of water and fat with echo asymmetry and least‐squares estimation (IDEAL).

Hyperpolarized (129) Xe imaging of the rat lung using spiral IDEAL.

To implement and optimize a single‐shot spiral encoding strategy for rapid 2D IDEAL projection imaging of hyperpolarized (Hp) 129Xe in the gas phase, and in the pulmonary tissue (PT) and red blood cells (RBCs) compartments of the rat lung, respectively.

Hyperpolarized (1- 13 C)Pyruvate MRI for Noninvasive Examination of Placental Metabolism and Nutrient Transport: A Feasibility Study in Pregnant Guinea Pigs

To test the feasibility of hyperpolarized [1‐13C]pyruvate magnetic resonance imaging (MRI) for noninvasive examination of guinea pig fetoplacental metabolism and nutrient transport.

Chemical shift encoded imaging of hyperpolarized 13C pyruvate

To demonstrate a reconstruction technique for separating signal from different hyperpolarized carbon‐13 metabolites.

On the accurate analysis of vibroacoustics in head insert gradient coils.

To accurately analyze vibroacoustics in MR head gradient coils.

Fat quantification using an interleaved bipolar acquisition

To demonstrate a new multigradient echo bipolar acquisition sequence for fat quantification.

Hyperpolarized choline as an MR imaging molecular probe: feasibility of in vivo imaging in a rat model.

To assess the feasibility of choline MRI using a new choline molecular probe for dynamic nuclear polarization (DNP) hyperpolarized MRI.

Flip angle mapping with the accelerated 3D look-locker sequence

A new approach to mapping the flip angle quickly and efficiently in 3D based on the Look‐Locker technique is presented.