One-step and label-free ratiometric fluorescence assay for the detection of plasma exosome towards cancer diagnosis.

Exosomes are closely associated with tumor development and are regarded as viable biomarkers for cancer. Here, a ratiometric fluorescence method was proposed for the one-step and label-free detection of plasma exosomes. A bicolor streptavidin magnetic beads were specifically created with an immobilized Cy5-labeled hairpin aptamer for CD63 (Cy5-Apt) on its surface to identify exosome, and a green color SYBR Green I (SGI) embedded in the stem of Cy5-Apt to respond to exosomes. After exosome capture, the Cy5-Apt could undergo a conformational shift and release the encapsulated SGI, allowing exosome measurement based on the fluorescence ratio of Cy5 and SGI. The enrichment, separation and detection of exosomes in proposed method could be completed in one step (30 min), which is a significant improvement over previous method. Furthermore, the use of ratiometric fluorescence and magnetic separation allows for exosome enrichment and interference elimination from complex matrices, improving accuracy and sensitivity. Particularly, the assay could detect exosomes in plasma and has potential to distinguish lung cancer patients from healthy volunteers with an area under the receiver operator characteristic curve of 0.85. Besides, the study provided an efficient method for analyzing the various divisions of exosomes by merely modifying the aptamer, which holds great promise for point-of-care applications.

Association of serum Asprosin concentrations with heart failure.

BACKGROUND: To analyze the association of serum Asprosin concentrations with heart failure (HF). METHODS: A total of 103 patients with HF were included in the HF group, and 103 patients with health checkups were included in the non-HF group. The serum Asprosin levels of the two groups were measured, and relevant clinical data were collected for statistical analysis. RESULTS: Compared with the non-HF group, the serum Asprosin concentration was significantly higher in the HF group, and the difference was statistically significant (P < 0.001). According to the serum Asprosin levels, we divided all the subjects into three quartiles. We found that the prevalence of HF increased with increasing serum Asprosin levels in the three groups (P < 0.001). Serum Asprosin levels were positively correlated with NT-ProBNP (P < 0.05) and negatively correlated with LVEF (P < 0.001). Dichotomous logistic regression analysis found Asprosin and age to be independent risk factors for HF (OR = 1.010, 95% CI: 1.003-1.018; OR = 1.058, 95% CI:1.004-1.665, respectively). Combining Asprosin and NT-proBNP indicators to draw ROC curves can improve the specificity and sensitivity of HF diagnosis. CONCLUSIONS: Serum Asprosin levels were significantly elevated in HF patients. The serum Asprosin level is an independent risk factor for HF, and the combined detection of Asprosin and NT-proBNP levels can improve the accuracy of HF diagnosis.

Screening of the differentially expressed proteins in malignant transformation of BEAS-2B cells induced by coal tar pitch extract.

Coal tar pitch extract (CTPE) was carcinogenic and could cause occupational lung cancer. Hence, we explored the changes of protein molecules during CTPE-induced malignant transformation (MT) of immortalized human bronchial epithelial (BEAS-2B) cells and provided clues for screening early biomarkers of CTPE-associated occupational lung cancer. The MT model of BEAS-2B cells induced by CTPE with 15.0 µg/mL. Subsequently, the MT of the BEAS-2B cells was verified by morphological observation, cell proliferation test, plate colony formation assay, and cell cycle assay. At the end of the experiment, we explored the differentially expressed proteins (DEPs) by total protein tandem mass tags quantitative proteomics technique between DMSO40 cells and CTPE40 cells. It was found that the proliferation ability, and colony formation rate were enhanced, and the cell cycle was changed. Then, bioinformatics analysis showed that a total of 107 DEPs were screened between CTPE40 and DMSO40 cells, of which 74 were up-regulated and 33 were down-regulated. As a result, 6 hub proteins were screened by protein-protein interaction network analysis. The expression levels of COX7A2, COX7C, MT-CO2, NDUFB4, and NDUFB7 were up-regulated as well as the expression of RPS29 protein was down-regulated. In summary, we established an MT model in vitro and explored the changes in protein molecules. As a result, this study suggested that changes of protein molecules, including COX7A2, COX7C, NDUFB7, MT-CO2, NDUFB4, and RPS29, occurred at the stage of BEAS-2B cell malignancy following CTPE exposure, which provided key information for screening biomarkers for CTPE-related occupational lung cancer.

Pho1 cooperates with DPE1 to control short maltooligosaccharide mobilization during starch synthesis initiation in rice endosperm.

KEY MESSAGE: Plastidial α-glucan phosphorylase is a key factor that cooperates with plastidial disproportionating enzyme to control short maltooligosaccharide mobilization during the initiation process of starch molecule synthesis in developing rice endosperm. Storage starch synthesis is essential for grain filling. However, little is known about how cereal endosperm controls starch synthesis initiation. One of core events for starch synthesis initiation is short maltooligosaccharide (MOS) mobilization consisting of long MOS primer production and excess MOS breakdown. By mutant analyses and biochemical investigations, we present here functional identifications of plastidial α-glucan phosphorylase (Pho1) and disproportionating enzyme (DPE1) during starch synthesis initiation in rice (Oryza sativa) endosperm. Pho1 deficiency impaired MOS mobilization, triggering short MOS accumulation and starch synthesis reduction during early seed development. The mutant seeds differed significantly in MOS level and starch content at 15 days after flowering and exhibited diverse endosperm phenotypes during mid-late seed development: ranging from pseudonormal to shrunken (Shr), severely or excessively Shr. The level of DPE1 was almost normal in the PN seeds but significantly reduced in the Shr seeds. Overexpression of DPE1 in pho1 resulted in plump seeds only. DPE1 deficiency had no obvious effects on MOS mobilization. Knockout of DPE1 in pho1 completely blocked MOS mobilization, resulting in severely and excessively Shr seeds only. These findings show that Pho1 cooperates with DPE1 to control short MOS mobilization during starch synthesis initiation in rice endosperm.

Cytosolic disproportionating enzyme2 is essential for pollen germination and pollen tube elongation in rice.

Degradation of starch accumulated in pollen provides energy and cellular materials for pollen germination and pollen tube elongation. Little is known about the function of cytosolic disproportionating enzyme2 (DPE2) in rice (Oryza sativa). Here, we obtained several DPE2 knockout mutant (dpe2) lines via genomic editing and found that the mutants grew and developed normally but with greatly reduced seed-setting rates. Reciprocal crosses between dpe2 and wild-type plants demonstrated that the mutant was male sterile. In vitro and in vivo examinations revealed that the pollen of the dpe2 mutant developed and matured normally but was defective in germination and elongation. DPE2 deficiency increased maltose content in pollen, whereas it reduced the levels of starch, glucose, fructose, and adenosine triphosphate (ATP). Exogenous supply of glucose or ATP to the germination medium partially rescued the pollen germination defects of dpe2. The expression of cytosolic phosphorylase2 (Pho2) increased significantly in dpe2 pollen. Knockout of Pho2 resulted in a semi-sterile phenotype. We failed to obtain homozygous dpe2 pho2 double mutant lines. Our results demonstrate that maltose catalyzed by DPE2 to glucose is the main energy source for pollen germination and pollen tube elongation, while Pho2 might partially compensate for deficiency of DPE2.

Gut microbiome and fecal metabolic alteration in systemic lupus erythematosus patients with depression.

Background: Mental health disorders in systemic lupus erythematosus (SLE) are gradually getting recognized; however, less is known regarding the actual structure and compositional alterations in gut microbiome and metabolism and the mechanisms of how they affect depression development in SLE patients. Methods: Twenty-one SLE patients with depression (SLE-d), 17 SLE patients without depression (SLE-nd), and 32 healthy controls (HC) were included in this study. Fecal samples were collected for 16S rRNA gene sequencing and ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) based metabolomics. Results: The structure of gut microbiome in the SLE-d group changed compared with that in the other two groups. The microbiome composition of SLE-d group showed decreased species richness indices, characterized by low ACE and Chao1 indices, a decrease in the ratio of phylum Firmicutes to Bacteroidetes, genus Faecalibacterium and Roseburia. A downregulation of the metabolite fexofenadine involved in bile secretion was positively correlated with the genus Faecalibacterium, Subdoligranulum and Agathobacter. Compared with the SLE-nd group, the SLE-d group had elevated serum levels of IL-2 and IL-6 and decreased BDNF. Interestingly, abundance of the genus Faecalibacterium and Roseburia was negatively correlated with IL-6, abundance of the genus Roseburia was negatively correlated with IL-2, and abundance of the genus Bacteroides was positively correlated with IL-2. Conclusion: This study identified specific fecal microbes and their metabolites that may participate in the development of SLE-d. Our findings provide a new perspective for improving depression in SLE patients by regulating the gut-brain axis.

Preparation of Fluorescent Carbon Dots Composites and Their Potential Applications in Biomedicine and Drug Delivery-A Review.

Carbon dots (CDs), a new member of carbon nanostructures, rely on surface modification and functionalization for their good fluorescence phosphorescence and excellent physical and chemical properties, including small size (<10 nm), high chemical stability, biocompatibility, non-toxicity, low cost, and easy synthesis. In the field of medical research on cancer (IARC), CDs, a new material with unique optical properties as a photosensitizer, are being applied to heating local apoptosis induction of cancer cells. In addition, imaging tools can also be combined with a drug to form the nanometer complex compound, the imaging guidance for multi-function dosage, so as to improve the efficiency of drug delivery, which also plays a big role in genetic diagnosis. This paper mainly includes three parts: The first part briefly introduces the synthesis and preparation of carbon dots, and summarizes the advantages and disadvantages of different preparation methods; The second part introduces the preparation methods of carbon dot composites. Finally, the application status of carbon dot composites in biomedicine, cancer theranostics, drug delivery, electrochemistry, and photocatalysis is summarized.

Computed tomography features and clinicopathological characteristics of gastric glomus tumor.

BACKGROUND: Gastric glomus tumor (GGT) is a rare neoplasm that is difficult to distinguish from other gastric submucosal tumors due to a lack of diagnostic experience. The goal of this study was to better understand GGT by looking at its clinicopathological features, computed tomography (CT) features, and differential diagnosis. METHODS: The clinical data and CT findings of 21 pathologically confirmed GGT patients were examined. The clinical characteristics and CT findings of benign GGT were compared to gastric stromal tumors (GST) (n = 30) and heterotopic pancreas (n = 30). RESULTS: The 21 cases included six males and fifteen females ranging in age from 42 to 64 years. The lesions were found in the gastric body in four cases and the antrum in seventeen. GGT was diagnosed as benign in 20 cases and malignant in one. In benign cases, the glomus cells were small, uniform, showed perivascular hemangiopericytoma­like or solid nest­like structures. Obvious mitotic figures were observed in the malignant case. SMA staining was positive in the tumor cells. A quasi-round or round solid mass protruded into the gastric cavity in 20 benign cases, with a clear and smooth edge. The long to short diameter ratio was 1.01 ± 0.15. All of the benign cases had obvious enhancement, with homogeneous enhancement in ten cases and heterogeneous enhancement in ten cases, as well as central filling enhancement in 12 cases. The ratio of CT value of lesion to abdominal aorta in arterial phase and venous phase were (0.41 ± 0.11) and (0.81 ± 0.20), which were significantly higher than GST and heterotopic pancreas. The irregular mass broke through the gastric wall and invaded liver with poorly defined boundary and internal necrosis, heterogeneous persistent moderate enhancement with thickening blood supply arteries was seen in one malignant case with a long diameter of 150 mm and a thick diameter of 30 mm. CONCLUSIONS: CT enhancement usually shows persistent obvious enhancement, especially in arterial phase, which provides important value for the diagnosis. CT findings can help in the differential diagnosis of GGT and other submucosal tumors.

Evaluation of ischemia and necrosis in adhesive small bowel obstruction based on CT signs: Subjective visual evaluation and objective measurement.

PURPOSE: To investigate the diagnostic performance of CT signs for detecting bowel ischemia and necrosis in adhesive small bowel obstruction(SBO) with subjective and objective methods. MATERIALS AND METHODS: 113 adhesive SBO patients were enrolled and divided into ischemic group (49 cases in necrotic group and 35 cases in reversible ischemic group) and non-ischemic group (29 cases) according to the operation results. Subjective visual assessment of CT signs associated with ischemia and necrosis was performed by two radiologists independently. Elevated unenhanced attenuation and enhancement value of involved bowel wall were objectively measured and compared by single factor analysis of variance. Cut-off value and diagnostic performance were evaluated by receiver operating characteristic curve (ROC). RESULTS: Closed-loop mechanism, reduced bowel wall enhancement, and mesenteric edema were associated with bowel ischemia, with sensitivity of 81.0%, 65.5%, 75.0%, and specificity of 86.2%, 96.6%, 89.7%, respectively. Increased unenhanced bowel wall attenuation was a specific sign for necrosis with 100.0% specificity and 51.0% sensitivity. The sensitivity and specificity for ischemia were 86.0% and 91.9% with cut-off enhancement value lower than 33.5 HU. The sensitivity and specificity for necrosis were 58.2% and 100.0% with cut-off elevated unenhanced attenuation higher than 16.5 HU, 86.7% and 83.3% with cut-off enhancement value lower than 21.5 HU. CONCLUSION: Reduced bowel wall enhancement and increased unenhanced bowel wall attenuation were good indicators of bowel ischemia and necrosis. The objective measurement of elevated unenhanced attenuation and enhancement value can predict bowel ischemia and necrosis more accurately.

Sclerotinia sclerotiorum utilizes host-derived copper for ROS detoxification and infection.

Necrotrophic plant pathogen induces host reactive oxygen species (ROS) production, which leads to necrosis in the host, allowing the pathogen to absorb nutrients from the dead tissues. Sclerotinia sclerotiorum is a typical necrotrophic pathogen that causes Sclerotinia stem rot in more than 400 species, resulting in serious economic losses. Here, we found that three S. sclerotiorum genes involved in copper ion import/transport, SsCTR1, SsCCS and SsATX1, were significantly up-regulated during infection of Brassica oleracea. Function analysis revealed that these genes involved in fungal ROS detoxification and virulence. On the host side, four genes putatively involved in copper ion homeostasis, BolCCS, BolCCH, BolMT2A and BolDRT112, were significantly down-regulated in susceptible B. oleracea, but stably expressed in resistant B. oleracea during infection. Their homologs were found to promote resistance to S. sclerotiorum and increase antioxidant activity in Arabidopsis thaliana. Furthermore, copper concentration analysis indicated that copper flow from healthy area into the necrotic area during infection. A model was proposed that S. sclerotiorum utilizes host copper to detoxify ROS in its cells, whereas the resistant hosts may restrict the supply of essential copper nutrients to S. sclerotiorum by maintaining copper ion homeostasis during infection.

Can virtual monochromatic images from dual-energy CT replace low-kVp images for abdominal contrast-enhanced CT in small- and medium-sized patients?

OBJECTIVE: To investigate the image quality and radiation dose of dual-energy computed tomography (DECT) with automatic spectral imaging protocol selection (ASIS) compared with those of low-kVp CT in abdominal multiphase CT. METHODS: Four groups of 60 patients each underwent abdominal scans with low-kVp CT (A, 80 kVp/300 mg I/kg, body mass index [BMI] ≤ 23.9 kg/m2; C, 100 kVp/400 mg I/kg, BMI ranging from 24 to 28.9 kg/m2) or DECT with ASIS, and the 40- to 60-keV virtual monochromatic images (VMIs) generated (B and D) were matched by age, gender, BMI, cross-sectional area, and contrast agent dose; 9 patients were excluded due to technical failures. The CT number, image noise, contrast-to-noise ratio, and subjective image quality were compared between the matched protocols (A and B or C and D) on 1.25-mm reconstructed images. RESULTS: VMIs at approximately 55 keV and 62 keV had CT numbers and contrast similar to those of 80-kVp and 100-kVp CT images, respectively. Compared to matched low-kVp images, VMIs at 50 keV provided a higher CT number and image noise and a similar or higher contrast and overall image quality. The radiation dose for DECT was higher than that of 80-kVp CT (increased by 10%), but was similar to that of 100-kVp CT. CONCLUSION: Compared to matched low-kVp CT, VMIs at 50 keV in DECT with ASIS provided similar or higher overall image quality, with no or minimal dose penalty in small- and medium-sized patients. KEY POINTS: • Virtual monochromatic images at approximately 55 keV and 62 keV have CT numbers and contrast similar to those of 80-kVp and 100-kVp CT images, respectively, with a given noise index. • The radiation dose in dual-energy CT with automatic spectral imaging protocol selection was slightly higher than that of 80-kVp CT (increased by 10%) but was similar to that of 100-kVp CT. • Dual-energy CT may be able to replace l00-kVp CT for routine clinical abdominal contrast-enhanced CT scans.

Simultaneous Transcriptome Analysis of Host and Pathogen Highlights the Interaction Between Brassica oleracea and Sclerotinia sclerotiorum.

White mold disease caused by Sclerotinia sclerotiorum is a devastating disease of Brassica crops. Here, we simultaneously assessed the transcriptome changes from lesions produced by S. sclerotiorum on disease-resistant (R) and -susceptible (S) B. oleracea pools bulked from a resistance-segregating F2 population. Virulence genes of S. sclerotiorum, including polygalacturonans, chitin synthase, secretory proteins, and oxalic acid biosynthesis, were significantly repressed in lesions of R B. oleracea at 12 h postinoculation (hpi) but exhibited similar expression patterns in R and S B. oleracea at 24 hpi. Resistant B. oleracea induced expression of receptors potentially to perceive Sclerotinia signals during 0 to 12 hpi and deployed complex strategies to suppress the pathogen establishment, including the quick accumulation of reactive oxygen species via activating Ca2+ signaling and suppressing pathogen oxalic acid generation in S. sclerotiorum. In addition, cell wall degradation was inhibited in the resistant B. oleracea potentially to prevent the expansion of Sclerotinia hyphae. The transcriptome changes in S. sclerotiorum and host revealed that resistant B. oleracea produces strong responses against S. sclerotiorum during early infection.

Spectral computed tomography in advanced gastric cancer: Can iodine concentration non-invasively assess angiogenesis?

AIM: To investigate the correlation of iodine concentration (IC) generated by spectral computed tomography (CT) with micro-vessel density (MVD) and vascular endothelial growth factor (VEGF) expression in patients with advanced gastric carcinoma (GC). METHODS: Thirty-four advanced GC patients underwent abdominal enhanced CT in the gemstone spectral imaging mode. The IC of the primary lesion in the arterial phase (AP) and venous phase (VP) were measured, and were then normalized against that in the aorta to provide the normalized IC (nIC). MVD and VEGF were detected by immunohistochemical assays, using CD34 and VEGF-A antibodies, respectively. Correlations of nIC with MVD, VEGF, and clinical-pathological features were analyzed. RESULTS: Both nICs correlated linearly with MVD and were higher in the primary lesion site than in the normal control site, but were not correlated with VEGF expression. After stratification by clinical-pathological subtypes, nIC-AP showed a statistically significant correlation with MVD, particularly in the group with tumors at stage T4, without nodular involvement, of a mixed Lauren type, where the tumor was located at the antrum site, and occurred in female individuals. nIC-VP showed a positive correlation with MVD in the group with the tumor at stage T4 and above, had nodular involvement, was poorly differentiated, was located at the pylorus site, of a mixed and diffused Lauren subtype, and occurred in male individuals. nIC-AP and nIC-VP showed significant differences in terms of histological differentiation and Lauren subtype. CONCLUSION: The IC detected by spectral CT correlated with the MVD. nIC-AP and nIC-VP can reflect angiogenesis in different pathological subgroups of advanced GC.

[Preoperative assessment value of spectral CT quantitative parameters in lymph node metastasis of gastric cancer].

OBJECTIVE: To investigate the preoperative assessment value of spectral CT quantitative parameters in lymph node metastasis of gastric cancer. METHODS: From December 2013 to June 2015, clinical and image data of 86 patients with gastric cancer confirmed by gastroscope pathology undergoing preoperative enhanced CT were prospectively collected. Enhanced CT included nonenhanced CT of conventional 120 kVp mode, arterial phase (AP) and venous phase (VP) with GSI mode on Discover GSI CT scanner. The raw data were transferred to ADW4.6 workstation to reconstruct the monochromatic images at 70 keV and iodine-based images in AP and VP with 1.25 mm thickness. The short diameter, long diameter, ratio of short to long diameter, CT attenuation and iodine value of lymph nodes in each phase were measured and recorded. Pathology results were used as golden standard. The spectral CT quantitative parameters of positive and negative lymph nodes were compared by t test and the sensitivity and specificity analyses were performed by ROC curves. This clinical study registration number 81271573. RESULTS: Among these 86 gastric cancer patients (53 male and 33 female), tumors of 28 cases were in upper part, of 12 cases in middle part, of 27 cases in distal part and of 19 cases involved two parts. Thirty-five cases were differentiated type and 51 cases were undifferentiated type. A total of 1 072 lymph nodes were found in operation, of which 412 nodes were positive and 660 were negative. Among 552 lymph nodes found in CT images, 338 nodes were positive and 214 were negative. Compared to negative lymph nodes, short diameter [(9.52±3.58) mm vs. (6.48±2.94) mm, t=4.639, P=0.000], ratio of short to long diameter (0.82±0.14 vs. 0.61±0.08, t=13.514, P=0.000), CT attenuation in precontrast [(20.44±6.77) Hu vs. (16.06±7.14) Hu, t=3.154, P=0.002], CT attenuation in AP[(61.71±11.78) Hu vs. (40.11±10.18) Hu, t=9.588, P=0.000], CT attenuation in VP[(71.34±13.03) Hu vs. (53.81±11.39) Hu, t=7.888, P=0.000], iodine value in AP [(16.17±4.22) 100 µg/cm3 vs. (8.03±3.10) 100 µg/cm3, t=9.781, P=0.000], the iodine value in VP [(20.13±6.04) 100 µg/cm3 vs. (11.58±4.13) 100 µg/cm3, t=10.147, P=0.000] of positive lymph nodes were greater. The long diameter was not significantly different between positive and negative lymph nodes [(11.71±5.63) mm vs. (10.64±3.20) mm, t=1.380, P=0.169]. The area under ROC curve of short diameter, ratio of short to long diameter, CT attenuation in precontrast, AP and VP, iodine value in AP and VP of lymph nodes was 0.600, 0.880, 0.648, 0.832, 0.755, 0.864, 0.835, respectively. Taking the ratio of short to long diameter over 0.72 as diagnosis standard, the sensitivity was 75.6% and the specificity was 93.5%. Taking the CT number in AP over 49.75 Hu, the sensitivity was 66.9% and the specificity was 88.8%. Taking the CT number in VP over 59.80 Hu, the sensitivity was 69.9% and the specificity was 77.6%. Taking the iodine value in AP over 9.65 (100 µg/cm3), the sensitivity was 80.4% and the specificity was 82.2%. Taking the iodine value in VP over 15.65 (100 µg/cm3), the sensitivity was 69.9% and the specificity was 86.9%. Combinong the ratio of short to long diameter with the iodine value in AP, the sensitivity was 95.2% and the specificity was 76.9%. CONCLUSIONS: The ratio of short to long diameter, the iodine value and CT attenuation in AP and VP of lymph nodes in spectral CT are important criteria to evaluate the metastasis of gastric cancer. Combining the ratio of short to long diameter with the iodine value in AP can obviously improve the sensitivity.

Automatic spectral imaging protocol selection and iterative reconstruction in abdominal CT with reduced contrast agent dose: initial experience.

OBJECTIVE: To evaluate the feasibility, image quality, and radiation dose of automatic spectral imaging protocol selection (ASIS) and adaptive statistical iterative reconstruction (ASIR) with reduced contrast agent dose in abdominal multiphase CT. METHODS: One hundred and sixty patients were randomly divided into two scan protocols (n = 80 each; protocol A, 120 kVp/450 mgI/kg, filtered back projection algorithm (FBP); protocol B, spectral CT imaging with ASIS and 40 to 70 keV monochromatic images generated per 300 mgI/kg, ASIR algorithm. Quantitative parameters (image noise and contrast-to-noise ratios [CNRs]) and qualitative visual parameters (image noise, small structures, organ enhancement, and overall image quality) were compared. RESULTS: Monochromatic images at 50 keV and 60 keV provided similar or lower image noise, but higher contrast and overall image quality as compared with 120-kVp images. Despite the higher image noise, 40-keV images showed similar overall image quality compared to 120-kVp images. Radiation dose did not differ between the two protocols, while contrast agent dose in protocol B was reduced by 33 %. CONCLUSION: Application of ASIR and ASIS to monochromatic imaging from 40 to 60 keV allowed contrast agent dose reduction with adequate image quality and without increasing radiation dose compared to 120 kVp with FBP. KEY POINTS: • Automatic spectral imaging protocol selection provides appropriate scan protocols. • Abdominal CT is feasible using spectral imaging and 300 mgI/kg contrast agent. • 50-keV monochromatic images with 50 % ASIR provide optimal image quality.

CT spectral imaging for monitoring the therapeutic efficacy of VEGF receptor kinase inhibitor AG-013736 in rabbit VX2 liver tumours.

PURPOSE: The aim of this study was to evaluate the value of computed tomography (CT) spectral imaging in assessing the therapeutic efficacy of a vascular endothelial growth factor (VEGF) receptor inhibitor AG-013736 in rabbit VX2 liver tumours. METHODS: Twenty-three VX2 liver tumour-bearing rabbits were scanned with CT in spectral imaging mode during the arterial phase (AP) and portal phase (PP). The iodine concentrations(ICs)of tumours normalized to aorta (nICs) at different time points (baseline, 2, 4, 7, 10, and 14 days after treatment) were compared within the treated group (n = 17) as well as between the control (n = 6) and treated groups. Correlations between the tumour size, necrotic fraction (NF), microvessel density (MVD), and nICs were analysed. RESULTS: The change of nICs relative to baseline in the treated group was lower compared to the control group. A greater decrease in the nIC of a tumour at 2 days was positively correlated with a smaller increase in tumour size at 14 days (P < 0.05 for both). The tumour nIC values in AP and PP had correlations with MVD (r = 0.71 and 0.52) and NF (r = -0.54 and -0.51) (P < 0.05 for all). CONCLUSIONS: CT spectral imaging allows for the evaluation and early prediction of tumour response to AG-013736. KEY POINTS: • AG-013736 treatment response was evaluated by CT in a rabbit tumour model. • CT spectral imaging allows for the early treatment monitoring of targeted anti-tumour therapies. • Spectral CT findings correlated with vascular changes after anti-tumour therapies. • Spectral CT is a promising method for assessing clinical treatment response.

[Application of spectral CT in the differentiation of stage T3 and T4a gastric carcinoma].

OBJECTIVE: To investigate the application value of spectral CT in the differentiation of stage T3 and T4a gastric carcinoma. METHODS: Data of 62 gastric cancer patients of stage T3 and T4a undergoing abdominal spectral CT examination in the First Affiliated Hospital of Zhengzhou University from December 2013 to December 2014 were collected retrospectively. There were 38 male and 24 female patients, with age of 33 to 77(58.6±10.4) years old. Abdominal double-phase enhanced scanning in gemstone spectral imaging mode was used to measure Iodine concentration (IC, 100 µg/ml) and water concentration(WC, 100 µg/ml) of perigastric fat tissue adjacent to the lesion during arterial phase(AP) and venous phase(VP), and normalized iodine concentration (nIC) was calculated respectively(nIC=IC/IC of aorta on the same slice). IC, WC, nIC of arterial phase and venous phase between stage T3 and T4a lesions were compared with double independent sample t test and compared with pathology. The diagnostic efficacy was evaluated using receiver operating characteristic (ROC) curve analysis. RESULTS: During arterial phase in stage T4a cases, IC (100 µg/ml) was -5.19±0.81 and nIC was -0.05±0.01, which was significantly higher than -3.44±1.54 (P=0.000) and -0.03±0.01 (P=0.000) in stage T3 cases. During venous phase in T4a cases, IC (100 µg/ml) was -3.78±0.94 and nIC was -0.04±0.01, which was significantly higher than -1.62±1.43 (P=0.000) and -0.02±0.02 (P=0.000) in stage T3 cases. As compared to arterial phase, IC and nIC of stage T4a and T3 of venous phase were more significantly different (all P<0.05). WC of stage T4a during arterial and venous phase was 955.72±15.68 and 949.86±17.36 respectively, while WC of stage T3 during arterial and venous phase was 947.77±18.43 and 942.46±18.53 respectively. There were no significant differences in WC between two stage cases during arterial and venous phase (P=0.106, P=0.143). ROC analysis showed that area under the ROC of IC and nIC during arterial phase was 0.829 and 0.867 respectively, and cut-off value of nIC was -0.039 for differentiation of stage T3 and T4a with corresponding 83.3% of sensitivity and 75.0% of specificity; area under the ROC of IC and nIC during venous phase was 0.873 and 0.905 respectively, and cut-off value of nIC was -0.031 for differentiation of stage T3 and T4a with corresponding 81.0% of sensitivity and 85.0% of specificity. CONCLUSIONS: Abdominal spectral CT scan is useful in the differentiation of stage T3 and T4a gastric carcinoma. The IC of perigastric fat tissue is significantly higher in stage T4a gastric carcinoma compared to stage T3 gastric carcinoma. Higher diagnostic efficacy can be obtained when taking -0.031 as the cut-off value of nIC during venous phase.

[Virtual unenhanced images derived from spectral CT imaging accessing gastric carcinoma: a feasible study].

OBJECTIVE: To qualitatively and quantitatively compare MSI images and WB images derived from spectral CT imaging with CU images in accessing gastric carcinoma. METHODS: The clinical data and imaging findings of 91 cases of gastric carcinomas between December 2013 and May 2015 were analyzed retrospectively. All patients underwent CU CT and enhanced CT with spectral imaging in AP and VP. MSI images were reconstructed based on monochromatic images of 70 keV in AP. WB images were obtained by water-iodine pair substance isolation of the AP images. Two abdominal radiologists independently evaluated the image quality and the depiction of gastric carcinoma in CU, MSI and WB images using a 5-point scale. The sensitivities of gastric cancer were evaluated by using enhanced images as the reference standard.The CT number of various regions, image noise, relative enhancement CT value of tumors and metastasis were measured and calculated on CU and MSI images. The CNR of gastric tumor were measured on CU, MSI and WB images. Effective radiation doses for triple-phase and dual-phase scan were calculated. Differences were tested for statistical significance using the Wilcoxon's signed rank test and the paired t-test. RESULTS: Interobserver agreement with regard to image quality and the depiction of gastric carcinoma was good(all kappa>0.70). There was no statistical significant difference in image quality between CU(4.30±0.63) and MSI(4.17±0.58) images(P>0.05), both higher than WB(3.87±0.84) images (both P<0.01). The depiction of gastric carcinoma in CU(3.86±0.50) and MSI(3.73±0.55) images had no statistical significant difference (P>0.05), and both higher than WB(3.34±0.38) images( both P<0.01). The sensitivities of CU, MSI and WB images were 91.2%, 95.6%, 93.4%. The CT number of gastric tumors, liver metastasis and aorta, image noise on MSI images were slightly higher than on TNE images(P<0.05). The CT number of gastric tumors, liver metastasis and aorta, image noise on MSI images were slightly higher than on TNE images(P<0.05). The CT number of lymph nodes, liver and muscle, CT relative enhancement value of gastric tumors, lymph nodes and liver metastasis had no significant difference between TNE and MSI images (all P>0.05). The CNR of gastric tumors had significant difference between groups: WB images were higher than MSI and MSI were higher than CU images(all P<0.01). The dose saving by removing the CU was 8.2 mSv(32%). CONCLUSION: The MSI images derived from spectral CT can provide comparable image quality to CU images and reliable diagnostic information for gastric tumors, which is superior to WB images, replacing CU images will lower radiation exposure by 32%.

Feasibility of virtual nonenhanced images derived from single-source fast kVp-switching dual-energy CT in evaluating gastric tumors.

PURPOSE: To assess the feasibility of virtual nonenhanced (VNE) images derived from single-source fast kVp-switching dual-energy CT, namely material suppressed iodine (MSI) images in evaluating gastric tumors, and to calculate potential radiation dose reductions for a dual-phase gemstone spectral imaging (GSI) abdominal CT compared with a standard triple-phase protocol. MATERIALS AND METHODS: The institutional review board approved this prospective study; all patients provided written informed consent. 95 patients underwent preoperative enhanced CT that included true nonenhanced (TNE) with conventional 120 kVp mode, arterial phase (AP) and venous phase (VP) with GSI mode. MSI images were obtained from enhanced images of AP. Two abdominal radiologists independently evaluated the image quality of TNE and MSI images using a 5-point scale. Interobserver agreement was accessed by kappa value. The sensitivity for lesions on TNE and MSI images were evaluated. The CT number of various regions and image noise was measured on TNE and MSI images. The relative enhancement CT value of lesions, contrast to noise(CNR) of gastric tumors and effective radiation doses for triple-phase and dual-phase protocol were calculated. Differences were tested for statistical significance using Wilcoxon signed rank test and paired t-test. RESULTS: Interobserver agreement about image quality was excellent(all kappa>0.750). No significant difference in image quality was found between TNE 4.32 ± 0.53 and MSI 4.21±0.51 images (P>0.05). In respect to the sensitivities for gastric tumors, lymph node and liver metastasis, there were no significant differences between TNE and MSI images (all P>0.05). The CT number on TNE and MSI images, respectively, for gastric tumor were 32.79HU ± 6.45 and 35.02HU ± 5.01 (P=0.006); lymph nodes, 31.33HU ± 6.37 and 31.61HU ± 5.73 (P=0.334); liver metastasis, 37.79HU ± 8.40 and 39.76HU ± 8.50 (P=0.041); liver, 56.56HU ± 7.87 and 58.32HU ± 8.73 (P=0.057); psoas muscle, 52.30HU ± 5.63 and 51.80HU±6.86 (P=0.533); aorta, 38.16HU ± 4.91 and 42.49HU ± 4.49 (P<0.001). The CT relative enhancement value of gastric tumors, lymph node and liver metastasis had no significant difference between TNE and MSI images (P=0.083, 0.194, 0.156). MSI images had higher image noise than TNE images (P<0.001). The CNR of gastric tumor on MSI images was higher than that on TNE images (P<0.001). The effective dose for triple-phase was 25.1mSv±6.2 and that for dual-phase was 17.7mSv ± 4.1. The dose saving by removing the TNE was 7.5 mSv (30.5%). CONCLUSION: In patients with gastric tumors, the MSI images derived from single-source fast kVp-switching dual-energy CT can provide comparable image quality to TNE images and reliable diagnostic information; replacing TNE images will lower radiation dose by 30.5%.