J Wang

Fred Hutchinson Cancer Research Center, Seattle, Washington, United States

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Publications (7)13.13 Total impact

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    ABSTRACT: AIM: To assess whether the three-dimensional (3D) black-blood motion-sensitized driven equilibrium (MSDE) prepared rapid gradient-echo sequence (3D MERGE) magnetic resonance imaging (MRI) sequence is sensitive enough to detect differences in atherosclerotic plaque size and morphology occurring in the adductor canal and the proximal bifurcation segment. MATERIALS AND METHODS: Fifty pairs of adductor canal and bifurcation segments from 25 patients with intermittent claudication were examined using 3D MERGE. The two-dimensional (2D) transverse section showing the largest plaque burden in each segment was chosen for comparison. Wall and lumen boundaries were segmented from each 2D section and quantified using six metrics: wall area (WA), lumen area (LA), normalized wall index (NWI), maximum wall thickness (MaxWT), minimum wall thickness (MinWT), and eccentricity. RESULTS: The mean LA in the adductor region was significantly lower than that in the bifurcation segment (p < 0.0001). Mean NWI, MaxWT, and eccentricity in the adductor region were significantly higher than those at bifurcation (p < 0.0001, p < 0.0021, and p < 0.0045, respectively). Mean WA and MinWT of the two segments did not show a statistically significant difference. WA in both regions was positively correlated with eccentricity (p < 0.0049 and p < 0.0049, respectively). LA was negatively correlated with eccentricity (p < 0.0017), and NWI was positively correlated with eccentricity only in the adductor region (p < 0.0004). CONCLUSION: The results suggest that compensatory enlargement was limited in the adductor canal when compared to the proximal bifurcation segment. 3D MERGE, as a fast and non-invasive sequence, may assist the evaluation of femoral atherosclerosis by assessing the size and morphology of plaques, knowledge of which can guide clinical treatment.
    Clinical Radiology 01/2013; · 1.66 Impact Factor
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    Bone marrow transplantation 04/2009; 44(6):387-9. · 3.00 Impact Factor
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    Rheumatology (Oxford, England) 01/2009; · 4.24 Impact Factor
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    ABSTRACT: To characterize vascular lesions in SSc disease with high-resolution magnetic resonance angiography (Micro-MRA) of the finger. Eight SSc subjects and eight age- and sex-matched healthy controls were recruited for this study. Among the SSc subjects, the mean +/- s.d. age was 54.5 +/- 4.9 yrs, and the mean +/- s.d. duration of disease was 8.3 +/- 8.4 yrs. The numbers of SSc subjects that had telangiectasia, calcinosis and impaired finger flexion were 3, 2 and 3, respectively. The 2D time-of-flight micro-MRA was performed on a 3T clinical MRI scanner using a custom-designed finger coil with an in-plane resolution of 0.16 x 0.21 mm(2) and slice thickness of 1.2 mm. The data for the proper palmar digital artery lumen area, the number of visible dorsal digital veins and a semi-quantitative vascular score, which evaluates the overall integrity of digital vessels, were independently evaluated by two experienced reviewers who were blinded to the status of the subject. Micro-MRA detected significant differences in the digital vasculature between SSc subjects and healthy volunteers. The SSc subjects had a significantly decreased digital artery lumen area (0.13 +/- 0.06 vs 0.53 +/- 0.26 mm(2), P < 0.001), a reduced number of digital veins (0.63 +/- 1.06 vs 3.13 +/- 0.99, P = 0.001) and a lowered overall vascular score (1.75 +/- 1.04 vs 3.5 +/- 0.53, P = 0.001). The study also found that both the digital artery lumen area (Pearson's; r = -0.72, P = 0.044) and vascular scores (Spearman's; rho = -0.75, P = 0.047) of the SSc subjects were inversely correlated with the duration of the disease. Micro-MRA can be used to identify and quantitatively characterize the vascular disease in SSc fingers. The parameters derived from micro-MRA could potentially be used as prospective biomarkers for clinical evaluation.
    Rheumatology (Oxford, England) 08/2008; 47(8):1239-43. · 4.24 Impact Factor
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    B CHU, J WANG, W SHUELY
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    ABSTRACT: Random copolymers of poly(isobutyl methacrylate-t-butylaminoethyl methacrylate) with Mw ∼ 2.4 × 106 g mol−1 could be shown to form more expanded coils in the very dilute solution regime (≲ 10−5 g ml−1) due to intramolecular repulsion, to associate in most solvents in the dilute solution regime (∼ 10−4 g ml−1) where inter- and intramolecular interactions are present, and to aggregate further in semidilute/concentrated solution regimes where intermolecular interactions dominate. The formation of larger aggregates in semidilute/concentrated solutions is responsible for its effectiveness as a polymer additive. At the same time, the rheological properties, such as the shear-rate dependence of the viscosity, tend to become more sensitive to concentration and temperature variations.
    Polymer. 01/1990; 31(5):805-811.
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    ABSTRACT: Introduction Multi contrast black blood (BB) carotid imaging is important for atherosclerosis diagnosis and accurate plaque component characterization [1, 2]. However, the most popular blood suppression methods, such as inflow pre-saturation band and double inversion recovery (DIR) are still susceptible to plaque mimicking flow artifacts that come from stagnant or slow flow. An alternative technique originally named 'diffusion preparation' sequence in combination with SSFP sequence has recently been proposed as a BB technique for vessel wall imaging [3]. This method, however, actually achieves BB effect by de-phasing rather than diffusion effect. Therefore, we would prefer to avoid the term 'diffusion', but naming it as motion sensitized driven equilibrium (MSDE) sequence. Unlike multi-contrast turbo spin echo (TSE) sequence, SSFP technique has a limited ability to discriminate plaque components. In this report, the MSDE preparation sequence is combined with the TSE sequence and compared to a previously validated multislice DIR sequence [4]. Methods Sequence Fig. 1 shows the MSDE sequence that is used in this study. The sequence is fully balanced around the 180º pulse. In the presence of flow, the flow suppression efficiency is determined by the de-phasing among moving spins, which is further determined by first and higher order gradient moments. To avoid any phase incoherence of the static spin, the total zeroth gradient moment value is kept to be zero. Optimization The BB capability of MSDE pre-pulse was first validated on a flow phantom (Phantom by Design, Bothell, WA). It was then optimized for in vivo scan to achieve the best blood suppression efficiency and also avoid significant signal drop caused by diffusion and T2 decay. All scans were performed on a 3T scanner (Philips Achieva R1.5.4, Best, Netherlands). A healthy volunteer (32, Male) was scanned after obtaining the informed consent. Oblique carotid artery scans (TR/TE 2000/8ms, FOV 160*160ms, slice thickness 2mm) with various first gradient moment values were performed at the same location. CNR between sternocleido muscle and lumen is used as the optimization goal. The sequence that presents highest CNR was chosen in the following comparison study. In vivo comparison The MSDE sequence is compared with the previously validated multi-slice DIR sequence [4] with TI of 290ms. Both MSDE and mDIR sequences use exactly the same T2w TSE readout sequence. The readout parameters are: TR/TE 4000/53ms, FOV 160*160mm, matrix 256*256, slice thickness 2mm, NSA 1. To compare the blood suppression efficiency, transversal MR images around carotid bifurcation were acquired on 3 atherosclerotic patients (mean age 59, 2M1F) after obtaining informed consents. After the images are acquired, the following comparisons were conducted.

Publication Stats

11 Citations
13.13 Total Impact Points

Institutions

  • 2009
    • Fred Hutchinson Cancer Research Center
      Seattle, Washington, United States
  • 2008–2009
    • University of Washington Seattle
      • • Department of Radiology
      • • Department of Bioengineering
      Seattle, Washington, United States