Zhengyang Zhou

Whole-Lesion Histogram Analysis of Apparent Diffusion Coefficient for the Assessment of Cervical Cancer.

Objective The aim of this study was to explore the application of whole-lesion histogram analysis of apparent diffusion coefficient (ADC) values of cervical cancer. Methods A total of 54 women (mean age, 53 years) with cervical cancers underwent 3-T diffusion-weighted imaging with b values of 0 and 800 s/mm2 prospectively. Whole-lesion histogram analysis of ADC values was performed. Paired sample t test was used to compare differences in ADC histogram parameters between cervical cancers and normal cervical tissues. Receiver operating characteristic curves were constructed to identify the optimal threshold of each parameter. Results All histogram parameters in this study including ADCmean, ADCmin, ADC10%–ADC90%, mode, skewness, and kurtosis of cervical cancers were significantly lower than those of normal cervical tissues (all P < 0.0001). ADC90% had the largest area under receiver operating characteristic curve of 0.996. Conclusions Whole-lesion histogram analysis of ADC maps is useful in the assessment of cervical cancer.

Added value of diffusion-weighted MR imaging to T2-weighted and dynamic contrast-enhanced MR imaging in T staging of gastric cancer☆

OBJECTIVE To assess the utilization of diffusion-weighted (DW) magnetic resonance (MR) imaging in T staging of gastric cancer prospectively. METHODS Fifty-one patients underwent T2-weighted (T2W), contrast-enhanced (CE) and DW MR imaging. Two radiologists independently interpreted the images for T staging of the tumors. RESULTS The overall accuracy of T staging in pT1-4 gastric cancers by T2W+CE+DW (88.2%) was significantly higher than that by T2W+CE and T2W+DW (both 76.5%, P=.031). CONCLUSION DW adds useful information to T2W and CE MR imaging in T staging of gastric cancer.

Preoperative T staging of gastric cancer: comparison of diffusion- and T2-weighted magnetic resonance imaging.

Objective The objective of our study was to assess the clinical feasibility of diffusion-weighted (DW) magnetic resonance (MR) imaging in preoperative T staging of gastric cancer prospectively. Methods Forty-five patients underwent axial T2-weighted (T2W) and DW (b, 0 and 1000 seconds/mm2) MR imaging. Two radiologists interpreted the images for detection and staging of the tumors independently. The McNemar test was used to check differences in diagnostic accuracy with the reference of postoperative histopathological results. Results Diffusion-weighted and T2W images detected 44 and 42 of 45 histologically confirmed lesions, respectively. Furthermore, DW images detected 11 of 12 pT1 lesions compared to 9 of 12 lesions by T2W images. The staging accuracy of advanced gastric cancer (≥pT2) in DW imaging is significantly higher than that in T2W imaging (87.9% and 69.7%, respectively; P < 0.05). Conclusions Diffusion-weighted is superior to T2W imaging in detection of early gastric cancers (pT1) and staging advanced cancers (≥pT2).

A dual-modal magnetic nanoparticle probe for preoperative and intraoperative mapping of sentinel lymph nodes by magnetic resonance and near infrared fluorescence imaging

The ability to reliably detect sentinel lymph nodes for sentinel lymph node biopsy and lymphadenectomy is important in clinical management of patients with metastatic cancers. However, the traditional sentinel lymph node mapping with visible dyes is limited by the penetration depth of light and fast clearance of the dyes. On the other hand, sentinel lymph node mapping with radionucleotide technique has intrinsically low spatial resolution and does not provide anatomic details in the sentinel lymph node mapping procedure. This work reports the development of a dual modality imaging probe with magnetic resonance and near infrared imaging capabilities for sentinel lymph node mapping using magnetic iron oxide nanoparticles (10 nm core size) conjugated with a near infrared molecule with emission at 830 nm. Accumulation of magnetic iron oxide nanoparticles in sentinel lymph nodes leads to strong T2 weighted magnetic resonance imaging contrast that can be potentially used for preoperative localization of sentinel lymph nodes, while conjugated near infrared molecules provide optical imaging tracking of lymph nodes with a high signal to background ratio. The new magnetic nanoparticle based dual imaging probe exhibits a significant longer lymph node retention time. Near infrared signals from nanoparticle conjugated near infrared dyes last up to 60 min in sentinel lymph node compared to that of 25 min for the free near infrared dyes in a mouse model. Furthermore, axillary lymph nodes, in addition to sentinel lymph nodes, can be also visualized with this probe, given its slow clearance and sufficient sensitivity. Therefore, this new dual modality imaging probe with the tissue penetration and sensitive detection of sentinel lymph nodes can be applied for preoperative survey of lymph nodes with magnetic resonance imaging and allows intraoperative sentinel lymph node mapping using near infrared optical devices.

Enzyme sensitive, surface engineered nanoparticles for enhanced delivery of camptothecin

To achieve a drug delivery system combining the programmable long circulation and targeting ability, surface engineering nanoparticles (NPs), having a sandwich structure consisting of a long circulating outmost layer, a targeting middle layer and a hydrophobic innermost core were constructed by mixing a matrix metalloproteinase MMP2 and MMP9-sensitive copolymers (mPEG-Pep-PCL) and folate receptor targeted copolymers (FA-PEG-PCL). Their physiochemical traits including morphology, particle size, drug loading content, and in vitro release profiles were studied. In vitro studies validated that the inhibition efficiency of tumor cells was effectively correlated with NP concentrations. Furthermore, The PEG layer would detach from the NPs due to the up-regulated extracellular MMP2 and MMP9 in tumors, resulting in the exposure of folate to enhance the cellular internalization via folate receptor mediated endocytosis, which accelerated the release rate of CPT in vivo. The antitumor efficacy, tumor targeting ability and bio-distribution of the NPs were examined in a B16 melanoma cells xenograft mouse model. These NPs showed improved tumor target ability and enhanced aggregation of camptothecin (CPT) in tumor site and prominent suppression of tumor growth. Thus this mPEG-Pep-PCL@FA-PEG-PCL core-shell structure NP could be a better candidate for the tumor specific delivery of hydrophobic drug.

Fabrication of Au@Ag core-shell NPs as enhanced CT contrast agents with broad antibacterial properties

Au@Ag core-shell nanoparticles (NPs) integrating both antibacterial and X-ray attenuation capabilities were facilely synthesized in aqueous solution. These NPs modified with methoxy-PEG-SH (m-PEG) on the surface rendered them favorable dispersity and stability in water, resulting in enhancement of their blood circulation time. X-ray photoelectron spectroscope (XPS) and high-resolution transmission electron microscope (HRTEM) results confirmed the core-shell structure of m-PEG-Au@Ag NPs. The m-PEG-Au@Ag NPs showed low cytotoxicity and strong X-ray absorption potency in vitro. Further in vivo study showed that as-synthesized NPs offered a pronounced contrast and prolonged their circulation time in the blood stream with negligible toxic effect in vivo. Besides, m-PEG-Au@Ag NPs had significant bacteriostatic effect toward common bacteria like Escherichia coli and Staphylococcus aureus as demonstrated by broth dilution assay. Given their low-cytotoxicity and high CT attenuation efficacy, m-PEG-Au@Ag NPs had a promising potential for use as CT enhancing and antibacterial agents.

Activatable Near‐Infrared Probe for Fluorescence Imaging of γ‐Glutamyl Transpeptidase in Tumor Cells and In Vivo

γ-Glutamyl transpeptidase (GGT) is a cell-membrane-bound enzyme that is involved in various physiological and pathological processes and is regarded as a potential biomarker for many malignant tumors, precise detection of which is useful for early cancer diagnosis. Herein, a new GGT-activatable near-infrared (NIR) fluorescence imaging probe (GANP) by linking of a GGT-recognitive substrate γ-glutamate (γ-Glu) and a NIR merocyanine fluorophore (mCy-Cl) with a self-immolative linker p-aminobenzyl alcohol (PABA) is reported. GANP was stable under physiological conditions, but could be efficiently activated by GGT to generate ≈100-fold enhanced fluorescence, enabling high sensitivity (detection limit of ≈3.6 mU L-1 ) and specificity for the real-time imaging of GGT activity as well as rapid evaluation of the inhibition efficacy of GGT inhibitors in living tumor cells. Notably, the deep tissue penetration ability of NIR fluorescence could further allow GANP to image GGT in frozen tumor tissue slices with large penetration depth (>100 μm) and in xenograft tumors in living mice. This GGT activatable NIR fluorescence imaging probe could facilitate the study and diagnosis of other GGT-correlated diseases in vivo.

Preoperative apparent diffusion coefficient value of gastric cancer by diffusion‐weighted imaging: Correlations with postoperative TNM staging

To determine if the apparent diffusion coefficient (ADC) values of gastric cancers on the preoperative diffusion weighted imaging (DWI) correlate with the postoperative TNMs of the lesions.

Assessment of histological differentiation in gastric cancers using whole-volume histogram analysis of apparent diffusion coefficient maps.

To investigate the efficacy of histogram analysis of the entire tumor volume in apparent diffusion coefficient (ADC) maps for differentiating between histological grades in gastric cancer.

Application of CT texture analysis in predicting histopathological characteristics of gastric cancers

ObjectivesTo explore the application of computed tomography (CT) texture analysis in predicting histopathological features of gastric cancers.MethodsPreoperative contrast-enhanced CT images and postoperative histopathological features of 107 patients (82 men, 25 women) with gastric cancers were retrospectively reviewed. CT texture analysis generated: (1) mean attenuation, (2) standard deviation, (3) max frequency, (4) mode, (5) minimum attenuation, (6) maximum attenuation, (7) the fifth, 10th, 25th, 50th, 75th and 90th percentiles, and (8) entropy. Correlations between CT texture parameters and histopathological features were analysed.ResultsMean attenuation, maximum attenuation, all percentiles and mode derived from portal venous CT images correlated significantly with differentiation degree and Lauren classification of gastric cancers (r, −0.231 ~ −0.324, 0.228 ~ 0.321, respectively). Standard deviation and entropy derived from arterial CT images also correlated significantly with Lauren classification of gastric cancers (r = −0.265, −0.222, respectively). In arterial phase analysis, standard deviation and entropy were significantly lower in gastric cancers with than those without vascular invasion; however, minimum attenuation was significantly higher in gastric cancers with than those without vascular invasion.ConclusionCT texture analysis held great potential in predicting differentiation degree, Lauren classification and vascular invasion status of gastric cancers.Key Points• CT texture analysis is noninvasive and effective for gastric cancer.• Portal venous CT images correlated significantly with differentiation degree and Lauren classification.• Standard deviation, entropy and minimum attenuation in arterial phase reflect vascular invasion.