Meng Yang

Peking Union Medical College Hospital, Peping, Beijing, China

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Publications (8)49.76 Total impact

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    ABSTRACT: We explored the efficacy of thin-slice volumetric 3-D ultrasound (3-DUS) in distinguishing between benign and malignant thyroid nodules. A total of 103 thyroid nodules were evaluated prospectively using 3-D gray-scale ultrasonography. The shape, margin, halo and potential capsular invasion of the nodules were compared with the findings of conventional 2-D ultrasound (2-DUS). Of the 103 thyroid nodules, there were 50 pathologically confirmed benign lesions and 53 malignant lesions (51.5%). Shape irregularity, ill-defined margins and capsular invasion provided sensitivities of 90.0%, 47.2% and 39.6% and specificities of 88.0%, 84.0% and 100%, respectively, for the malignant lesions. The diagnosis of thyroid cancer was improved in 3-DUS compared with 2-DUS, with a sensitivity of 88.7%, specificity of 90.0%, positive predictive value of 90.4%, negative predictive value of 88.2% and accuracy of 89.3%. The sensitivity of detection for lesions with capsular invasion increased to 39.6% with 3-DUS, more than twice that of 2-DUS. Three-dimensional US is highly accurate in diagnosing thyroid nodules, particularly those with capsular invasion.
    No preview · Article · Sep 2015 · Ultrasound in medicine & biology
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    ABSTRACT: Development of multifunctional nanoparticle-based probes for dual T1- and T2- weighted magnetic resonance imaging (MRI) could allow us to image and diagnose the tumors or other abnormalities in an exceptionally accurate and reliable manner. In this study, by fusing distinct nanocrystals via solid-state interfaces, hybrid hetero-nanostructures were built to combine both T1 and T2-weighted contrast agents together for MRI with high accuracy and reliability. The resultant hybrid hetero-trimers showed high stability in physiological condition and could induce both simultaneous positive and negative contrast enhancement in MR images. Small animal positron emission tomography imaging study revealed that the hybrid heterostructures displayed favorable biodistribution and were suitable for in vivo imaging. Their potential as dual contrast agents for T1 and T2 weighted MRI was further demonstrated by in vitro and in vivo imaging and relaxivity measurements.
    Preview · Article · Oct 2014 · ACS Nano
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    ABSTRACT: Anisotropic colloidal hybrid nanoparticles exhibit superior optical and physical properties compared to their counterparts with regular architectures. We herein developed a controlled, stepwise strategy to build novel anisotropic branched gold nano-architectures (Au-tripods) with predetermined composition and morphology for bio-imaging. The resultant Au-tripods with size less than 20 nm showed great promise as contrast agents for in vivo photoacoustic imaging (PAI). We further identified Au-tripods with two possible configurations as high absorbance nanomaterials from various gold multpods using a numerical simulation analysis. The PAI signals were linearly correlated with their concentrations after subcutaneous injection. The in vivo biodistribution of Au-tripods favorable for molecular imaging was confirmed using small animal positron emission tomography (PET). Intravenous administration of cyclic Arg-Gly-Asp-D-Phe-Cys (RGDfC) peptide conjugated Au-tripods (RGD-Au-tripods) to U87MG bearing mice showed almost 3-fold higher PAI contrasts in tumors than the blocking group. PAI result correlated well with the corresponding PET images. Quantitative biodistribution data revealed that 7.9 %ID/g of RGD-Au-tripods was accumulated in the U87MG tumor after 24 hour post injection. A pilot mouse toxicology study confirmed that no evidence of significant acute and systemic toxicity was observed in histopathological examination. Our study suggests that Au-tripods can be reliably synthesized through stringently controlled chemical synthesis, and could serve as a new generation of platform with high selectivity and sensitivity for multimodality molecular imaging.
    Full-text · Article · Feb 2014 · Journal of the American Chemical Society
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    ABSTRACT: A highly monodispersed hetero-nanostructure with two different functional nanomaterials (gold (Au) and iron oxide (Fe(3)O(4,) IO)) within one structure was successfully developed as Affibody based trimodality nanoprobe (positron emission tomography, PET; optical imaging; and magnetic resonance imaging, MRI) for imaging of epidermal growth factor receptor (EGFR) positive tumors. Unlike other regular nanostructures with a single component, the Au-IO hetero-nanostructures (Au-IONPs) with unique chemical and physical properties have capability to combine several imaging modalities together to provide complementary information. The IO component within hetero-nanostructures serve as a T(2) reporter for MRI; and gold component serve as both optical and PET reporters. Moreover, such hetero-nanoprobes could provide a robust nano-platform for surface-specific modification with both targeting molecules (anti-EGFR Affibody protein) and PET imaging reporters (radiometal (64)Cu chelators) in highly efficient and reliable manner. In vitro and in vivo study showed that the resultant nanoprobe provided high specificity, sensitivity, and excellent tumor contrast for both PET and MRI imaging in the human EGFR-expressing cells and tumors. Our study data also highlighted the EGFR targeting efficiency of hetero-nanoparticles and the feasibility for their further theranostic applications.
    No preview · Article · Jan 2013 · Biomaterials
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    ABSTRACT: Fibroblast activation protein-alpha (FAPα) is a cell surface glycoprotein which is selectively expressed by tumor-associated fibroblasts in malignant tumors but rarely on normal tissues. FAPα has also been reported to promote tumor growth and invasion and therefore has been of increasing interest as a promising target for designing tumor-targeted drugs and imaging agents. Although medicinal study on FAPα inhibitors has led to the discovery of many FAPα-targeting inhibitors including a drug candidate in a phase II clinical trial, the development of imaging probes to monitor the expression and activity of FAPα in vivo has largely lagged behind. Herein, we report an activatable near-infrared (NIR) fluorescent probe (ANP(FAP)) for in vivo optical imaging of FAPα. The ANP(FAP) consists of a NIR dye (Cy5.5) and a quencher dye (QSY21) which are linked together by a short peptide sequence (KGPGPNQC) specific for FAPα cleavage. Because of the efficient fluorescence resonance energy transfer (FRET) between Cy5.5 and QSY21 in ANP(FAP), high contrast on the NIR fluorescence signal can be achieved after the cleavage of the peptide sequence by FAPα both in vitro and in vivo. In vitro assay on ANP(FAP) indicated the specificity of the probe to FAPα. The in vivo optical imaging using ANP(FAP) showed fast tumor uptake as well as high tumor to background contrast on U87MG tumor models with FAPα expression, while much lower signal and tumor contrast were observed in the C6 tumor without FAPα expression, demonstrating the in vivo targeting specificity of the ANP(FAP). Ex vivo imaging also demonstrated ANP(FAP) had high tumor uptake at 4 h post injection. Collectively, these results indicated that ANP(FAP) could serve as a useful NIR optical probe for early detection of FAPα expressing tumors.
    No preview · Article · Jul 2012 · Bioconjugate Chemistry
  • Meng Yang · Susan Hoppmann · Luxi Chen · Zhen Cheng
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    ABSTRACT: Molecular imaging is a fast growing field in biomedical research. The discovery, development and continual improvement of molecular probes are important for ongoing research efforts in molecular imaging. Human serum albumin (HSA) offers favorable characteristics and opportunities as a platform protein for molecular imaging probe discovery and optimization. It has many advantages, including alternation of biodistribution and pharmacokinetic properties of molecular imaging probes, enhancing the blood half-life of bio-molecules, and making these molecules multivalent, all of which make HSA a promising carrier for cancer-targeted imaging and therapy. Numerous studies have focused on the development and application of HSA-based cancer imaging and treatment. This review gives a brief account of albumin-based molecular probes, focusing on their applications in cancer molecular imaging, such as PET/SPECT, MRI and optical imaging.
    No preview · Article · Jan 2012 · Current pharmaceutical design
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    ABSTRACT: The purpose of this study was to evaluate the utility of contrast-enhanced sonography as an adjunct to conventional transvaginal sonography for detecting endometrial carcinoma and defining the depth of myometrial invasion. A total of 35 patients with endometrial carcinoma diagnosed by endometrial sampling were examined with transvaginal sonography followed by contrast-enhanced sonography before treatment. The contrast enhancement phases (ie, early wash-in/out and late wash-in/out) were visually observed before comparison of tumors grouped by average diameter and histopathologic grade. We evaluated the effectiveness of contrast-enhanced sonography as an adjunct to transvaginal sonography in tumor imaging. We calculated the accuracy of contrast-enhanced sonography for diagnosing the depth of tumor invasion into the myometrium by using arcuate vascular plexus involvement as the sonographic standard for diagnosis of deep myometrial infiltration. Of the 34 tumors identified by contrast-enhanced sonography, 28 (82.4%) showed early wash-in, and 6 (17.6%) showed late wash-in. Similar numbers of cases showed early and late wash-out. The enhancement phases did not differ significantly across groups with different average tumor diameters or histologic grades (P > .05). Contrast-enhanced sonography contributed the most to tumor imaging in patients with a thin endometrium after endometrial biopsy because it enhanced the contrast between the tumor and tissue. The diagnostic accuracy of contrast-enhanced sonography for determining the myometrium infiltration depth was 85.3%. This study revealed diagnostically useful characteristics of the enhancement phase of endometrial carcinoma. The ability to enhance tumor-to-tissue contrast makes contrast-enhanced sonography a valuable adjunct to conventional sonography of endometrial carcinoma, especially for the thin endometrium found after endometrial biopsy. Contrast-enhanced sonography performed well in the diagnosis of the myometrial infiltration depth when using arcuate vascular plexus involvement as a marker of deep myometrial infiltration.
    No preview · Article · Nov 2011 · Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine
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    ABSTRACT: No conventional imaging method reliably distinguishes between benign and malignant thyroid nodules. Our objectives were to characterize the enhancement patterns of thyroid nodules on gray-scale contrast-enhanced ultrasound (US) and to evaluate whether these patterns were useful in the differential diagnosis of thyroid nodules. Ninety-five patients, scheduled for surgery for thyroid nodules detected by gray-scale sonography, were enrolled in this prospective study. In all, there were 104 nodules (47 papillary carcinomas, 3 medullary carcinomas, 1 metastatic carcinoma, 44 hyperplasia nodule, 7 follicular adenomas, 1 suture granulomas, and 1 Hashimoto's disease). After intraveneous (i.v.) injection of a 1.2 mL bolus of SonoVue, lesions were scanned with real-time gray-scale pulse inversion harmonic imaging US for at least 3 minutes at low mechanical index (MI) (0.05 to 0.08). The enhancement patterns were classified into one of four patterns by two experienced readers. After administration of SonoVue, four enhancement patterns (homogeneous, heterogeneous, ring-enhancing, and no enhancement) were observed. Four benign and 3 malignant nodules had homogeneous enhancement pattern, 4 benign and 45 malignant nodules had heterogeneous enhancement, 44 benign and 3 malignant nodules had ring enhancement, and 1 benign nodule had no enhancement. There was a significant difference between benign and malignant nodules (p < 0.001). The benign thyroid nodules showed four enhancement patterns: ring enhancement 44/53 (83.0%), homogeneous enhancement 4/53 (7.5%), heterogeneous enhancement 4/53 (7.5%), and no enhancement 1/44 (1.9%). The malignant thyroid nodules showed three enhancement patterns: heterogeneous enhancement 45/51 (88.2%), ring enhancement 3/51 (5.9%), and homogeneous enhancement 3/51 (5.9%). Ring enhancement correlated highly with a benign diagnosis (sensitivity 83.0%, specificity 94.1%, positive predictive value 93.6%, negative predictive value 84.2%, and accuracy 88.5%). Heterogeneous enhancement correlated highly with a malignant diagnosis (sensitivity 88.2%, specificity, 92.5% positive predictive value 91.8%, negative predictive value 89.1%, and accuracy 90.4%). In both mixed and solid nodules, ring enhancement was highly predictive of a benign finding, whereas heterogeneous enhancement was highly predictive of a malignant finding. Contrast-enhanced US enhancement patterns were different in benign and malignant lesions. Ring enhancement was predictive of benign lesions, whereas heterogeneous enhancement was helpful for detecting malignant lesions.
    No preview · Article · Jan 2010 · Thyroid: official journal of the American Thyroid Association