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Highly stable and multicolor photoluminescent (PL) quantum dots (QDs) have attracted widespread attention as ideal probe materials in the field of in vitro diagnostics (IVD), especially the fluorescence-linked immunosorbent assay (FLISA), due to their advantages of high-throughput, high stability, and high sensitivity. However, the size of QDs as fluorescent probes have significant effects on antigen-antibody performance. Therefore, it is critical to design suitable QDs for obtain excellent quantitative detection-based biosensors. In this paper, we prepared different sizes of aqueous QDs (30 nm, 116 nm, 219 nm, and 320 nm) as fluorescent probes to optimize the competitive FLISA platform. The SARS-CoV-2 neutralizing antibody (NTAB) assay was used as an example, and it was found that the size of the QDs has a significant impact on the antigen-antibody binding efficiency and detection sensitivity in competitive FLISA platform. The results showed that these QD nanobeads (QBs, ∼219 nm) could be used as a labeled probe for competitive FLISA, with half-maximal inhibitory concentration (IC50) of 1.34 ng/mL and limit of detection (LOD) of 0.21 pg/mL for NTAB detection. More importantly, the results showed good specificity and accuracy, and the QB 219 probe was able to efficiently bind NTAB without interference from other substances in the serum. Given the above advantages, the nanoprobe material (∼200 nm) offers considerable potential as a competitive FLISA platform in the field of IVD., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

The excellent optical properties of quantum dots (QDs) make them as an ideal fluorescent probe for multiplexed detection, however, the interference between different emission spectra, the dependence of excitation wavelengths, and the sharp decrease of quantum yield (QY) during surface modification are issues that cannot be ignored. Herein, a dual protection scheme of polymer and silica was proposed to prepare high-quality three-color QDs nanobeads using QDs with different ligands. In comparison with single-core QDs, the fluorescence signal of the prepared QD nanobeads (QBs) is increased by more than 1,000 times and has better stability. Considering the excitation efficiency of QDs, we tailor three-color QBs as fluorescent probes based on fluorescence-linked immunosorbent assays (tQBs-FLISA) to detect multiple inflammatory biomarkers simultaneously with tunable detection ranges. This resulted in highly sensitive detection of three inflammatory biomarkers in comparison to the single-core QD-FLISA, the sensitivities of C-reactive protein (CRP), serum amyloid A (SAA), and procalcitonin (PCT) were increased by 16-fold, 19-fold, and 5-fold, respectively, to 0.48 ng/mL, 0.42 ng/mL, and 10 pg/mL. Furthermore, the tQBs-FLISA showed good accuracy without interference from common serum factors. In this strategy, a three-color QBs suitable for multilevel sensitivity and tunable detection range was tailored using the versatile polymer and silica dual protection method, building high-performance immunosensor for in vitro diagnostics (IVD)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Background: After neoadjuvant therapy, most of the lymph nodes (LNs) will shrink and disappear in patients with rectal cancer. However, LNs that are still detectable on MRI carry a risk of metastasis. This study aimed to evaluate the performance of the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) criterion (short-axis diameter ≥ 5 mm) in diagnosing malignant LNs in patients with rectal cancer after neoadjuvant therapy, and whether nodal morphological characteristics (including shape, border, signal homogeneity, and enhancement homogeneity) could improve the diagnostic efficiency for LNs ≥ 5 mm., Methods: This retrospective study included 90 patients with locally advanced rectal cancer who underwent surgery after neoadjuvant therapy and performed preoperative MRI. Two radiologists independently measured the short-axis diameter of LNs and evaluated the morphological characteristics of LNs ≥ 5 mm in consensus. With a per node comparison with histopathology as the reference standard, a ROC curve was performed to evaluate the diagnostic performance of the size criterion. For categorical variables, either a χ 2 test or Fisher's exact test was used., Results: A total of 298 LNs were evaluated. The AUC for nodal size in determining nodal status was 0.81. With a size cutoff value of 5 mm, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 65.9%, 87.0%, 46.8%, 93.6% and 83.9%, respectively. No significant differences were observed in any of the morphological characteristics between benign and malignant LNs ≥ 5 mm (all P > 0.05)., Conclusions: The ESGAR criterion demonstrated moderate diagnostic performance in identifying malignant LNs in patients with rectal cancer after neoadjuvant therapy. It was effective in determining the status of LNs < 5 mm but not for LNs ≥ 5 mm, and the diagnostic efficiency could not be improved by considering nodal morphological characteristics., (© 2023. The Author(s).)

Calcification causes mixed signal intensity in the lymph node (LN) on high-resolution magnetic resonance imaging (MRI), which is a strong indicator of regional LN metastasis in rectal cancer. Calcified metastatic LNs in rectal cancer commonly display scattered fine punctate calcifications to varying degrees on computed tomography (CT). On high-resolution MRI, the calcifications manifest a patchy area of signal loss in corresponding calcified area that is larger than on CT. It is necessary to recognize the appearance of metastatic LN calcifications on high-resolution MRI in rectal cancer because it is the primary imaging method for local staging in rectal cancer. This pictorial essay aims to introduce an important imaging finding that can contribute to the diagnosis of LN metastasis by illustrating features and differences between CT and high-resolution MRI of metastatic LN calcifications in rectal cancer.

Rationale and Objectives: To analyze CT and high-resolution MRI findings of nodal metastasis calcifications and determine the value of high-resolution MRI in detecting nodal calcifications in rectal cancer patients., Materials and Methods: In total, 229 rectal cancer patients were included. The CT was reviewed for the presence of nodal calcifications by two radiologists. High-resolution two-dimensional turbo spin-echo T2-weighted imaging (2D-TSE-T2WI) and fat-suppressed gadolinium-enhanced isotropic high-resolution three-dimensional gradient-echo T1-weighted imaging (3D-GRE-T1WI) were independently reviewed for nodal calcifications by the two radiologists at one-month and two-month intervals, respectively. The sensitivities, specificities and accuracies of the two high-resolution MRI in detecting nodal calcifications were calculated using CT results as a reference., Results: Regional calcified metastatic lymph nodes were found in 28 patients. The node-to-node evaluation revealed that 55 (98.2%) of the 56 calcified lymph nodes were metastatic. Fifty-one (92.7%) calcified metastatic lymph nodes displayed scattered fine punctate calcifications to different degrees on CT. In both types of high-resolution MRI, the calcifications demonstrated a patchy area of markedly reduced signal intensity in corresponding areas that were larger than those on CT. The sensitivity and accuracy of fat-suppressed gadolinium-enhanced isotropic high-resolution 3D-GRE-T1WI were significantly higher than those of high-resolution 2D-TSE-T2WI (76.8% vs 58.9%, P = 0.013; 98.3% vs 97.9%, P = 0.007; respectively)., Conclusion: Metastatic nodal calcifications are characteristic imaging findings in rectal cancer. Calcifications are indicated by markedly reduced signal on high-resolution MRI, which will alert radiologists to scrutinize CT for nodal calcifications and aid in the accurate diagnosis of metastatic lymph nodes., Competing Interests: Declaration of Competing Interest None., (Copyright © 2020 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

OBJECTIVE. The purpose of this study was to use quantitative dynamic contrast-enhanced MRI (DCE-MRI) to evaluate mesorectal microcirculation in patients with rectal cancer. MATERIALS AND METHODS. A total of 53 patients with semicircular rectal tumors underwent DCE-MRI with a 3-T MRI system before surgery. ROIs were manually delineated in the mesorectum that surrounded the tumor and the mesorectum that surrounded the normal rectal wall. DCE-MRI parameters including forward volume transfer constant (K trans ), reverse volume transfer constant (k ep ), and fractional extravascular extracellular space volume (V e ) were estimated using computer software. Histopathologic analysis served as the standard reference. RESULTS. Mesorectum that surrounded the tumor showed significantly higher K trans val ues than mesorectum that surrounded normal rectal wall (mean, 0.069 ± 0.035 [SD] vs 0.039 ± 0.020 min -1 ; p < 0.001). The tumor-surrounding mesorectum also showed higher V e values than normal mesorectum ( p < 0.001). An opposite trend was observed for k ep , but this was not significant ( p = 0.077). A lower K trans of the tumor-surrounding mesorectum was observed in patients with malignant lymph nodes compared with those with benign lymph nodes (mean, 0.054 ± 0.027 vs 0.076 ± 0.036 min -1 ; p = 0.034). Although k ep values for the tumor-surrounding mesorectum were higher in patients with tumors categorized as pathologic Tis (pTis) to pT2 than in those with pT3 tumors, the p value was close to 0.05 ( p = 0.047). The tumor-surrounding mesorectum showed no significant differences in the aforementioned parameters between patients with positive MRI-detected extramural vascular invasion (mrEMVI) and those with negative mrEMVI. CONCLUSION. Mesorectum that surrounded rectal tumor had a higher blood flow than that close to the normal rectal wall. The blood flow decreased in the tumor-surrounding mesorectum when there was nodal involvement.

Background: The aim of this study is to evaluate the microstructure and microcirculation of regional lymph nodes (LNs) in rectal cancer by using non-invasive intravoxel incoherent motion MRI (IVIM-MRI), and to distinguish metastatic from non-metastatic LNs by quantitative parameters., Methods: All recruited patients underwent IVIM-MRI (b = 0, 5, 10, 20, 30, 40, 60, 80, 100, 150, 200, 400, 600, 1000, 1500 and 2000 s/mm 2 ) on a 3.0 T MRI system. One hundred sixty-eight regional LNs with a short-axis diameter equal to or greater than 5 mm from 116 patients were evaluated by two radiologists independently, including 78 malignant LNs and 90 benign LNs. The following parameters were assessed: the short-axis diameter (S), long-axis diameter (L), short- to long-axis diameter ratio (S/L), pure diffusion coefficient (D), pseudo-diffusion coefficient (D * ), and perfusion factor (f). Intraclass correlation coefficients (ICCs) were calculated to assess the interobserver agreement between two readers. Receiver operating characteristic curves were applied for analyzing statistically significant parameters., Results: Interobserver agreement of IVIM-MRI parameters between two readers was excellent (ICCs> 0.75). The metastatic group exhibited higher S, L and D (P < 0.001), but lower f (P < 0.001) than the non-metastatic group. The area under the curve (95% CI, sensitivity, specificity) of the multi-parameter combined equation for D, f and S was 0.811 (0.744~0.868, 62.82%, 87.78%). The diagnostic performance of the multi-parameter model was better than that of an individual parameter (P < 0.05)., Conclusion: IVIM-MRI parameters provided information about the microstructure and microcirculation of regional LNs in rectal cancer, also improved diagnostic performance in identifying metastatic LNs.

Purpose: To compare the diagnostic accuracies of MDCT and high-resolution MRI (HR-MRI) for regional nodal metastases with different short-axis diameter ranges in rectal cancer patients., Methods: Rectal adenocarcinoma patients who underwent both MDCT and HR-MRI before surgery were included. The maximum short-axis diameters of the nodes were measured, and were classified as benign or malignant on imaging findings. All of the nodes were subdivided as follows: ≤ 5 mm (Group A), > 5 mm and ≤ 10 mm (Group B) , and > 10 mm (Group C). The postoperative pathological reports were used as the standard, and the sensitivity, specificity, accuracy, ROC curve, and AUC value were calculated for each subgroup., Results: A total of 592 nodes were included in the node-to-node evaluation. In Group A, the specificity and accuracy of HR-MRI were significantly higher than those of MDCT (99.28% vs. 93.99%, P < 0.001; 95.78% vs. 89.56%, P = 0.010; respectively). In Group B, the specificity and accuracy of HR-MRI were also higher than those of MDCT (98.36% vs. 55.74%, P < 0.001; 80.45% vs. 66.17%, P < 0.001; respectively). For Groups A and B, the AUCs of MDCT were both 0.65, whereas those of HR-MRI were 0.76 and 0.82, respectively. In Group C, all nine malignant nodes were correctly diagnosed metastases on MDCT, whereas one was misjudged as benign on HR-MRI., Conclusions: The diagnostic value of HR-MRI is superior to that of MDCT, with higher specificity, accuracy, and AUC values for HR-MRI than for MDCT.

Background: To determine whether magnetic resonance imaging (MRI)-detected extramural vascular invasion (mrEMVI) status is associated with quantitative perfusion parameters derived from dynamic contrast-enhanced MRI (DCE-MRI) in rectal cancer., Methods: Seventy-two patients with rectal adenocarcinoma who underwent curative surgery alone within 2 weeks following rectal MRI were enrolled in this retrospective study. mrEMVI status was determined based on high-resolution MRI. The quantitative perfusion parameters (K trans , k ep and v e ) derived from DCE-MRI were calculated from all sections containing tumours. DCE-MRI parameters and clinicopathological variables in patients with different mrEMVI statuses were compared., Results: For patients who were mrEMVI positive, the tumours demonstrated significantly lower k ep values (P = 0.012) and higher v e values (P = 0.021) than tumours of patients who were mrEMVI negative, while the K trans value displayed no significant difference (P = 0.390). The patients who were mrEMVI positive had larger tumour size, higher pathological tumour stage and increased regional nodal metastases compared to those who were mrEMVI negative (2.9 cm vs. 3.5 cm, P = 0.011; 63.8% vs. 92.0%, P = 0.010; 36.2% vs. 76.0%, P = 0.001; respectively)., Conclusions: This study demonstrated for the first time that tumour microcirculation is altered in mrEMVI-positive patients with rectal adenocarcinoma, as evidenced by significantly lower k ep and higher v e values. In addition, these patients were more likely to have a larger tumour size, a higher pathological tumour stage and regional nodal metastases than mrEMVI-negative patients.

Background: Intravoxel incoherent motion magnetic resonance imaging (IVIM-MRI) acquires tumor perfusion information without injection of contrast medium, which is promising in tumor assessment. However, its consistency with dynamic contrast-enhanced MRI (DCE-MRI), a more widely used method for tumor perfusion evaluation, is not revealed in rectal cancer., Purpose: In this study, we aimed to investigate the correlation of perfusion-sensitive parameters derived from IVIM-MRI with DCE-MRI and measurement reproducibility of IVIM-MRI parameters in rectal cancer., Material and Methods: Forty-seven rectal cancer patients underwent IVIM-MRI with 16 b-values and DCE-MRI. The perfusion fraction ( f), pseudo-diffusion coefficient ( D*), and f· D* were measured by two radiologists independently and correlated with the transfer constant ( K trans ), reflux constant ( k ep ), and extravascular extracellular fractional volume ( v e ) obtained from DCE-MRI., Results: Pearson's correlation analyses of IVIM-MRI and DCE-MRI parameters showed fair to moderate correlation between f and K trans ( r = 0.461, P = 0.001), followed by f and k ep ( r = 0.430, P = 0.003), f·D*, and K trans ( r = 0.425, P = 0.003), f·D*, and k ep ( r = 0.384, P = 0.008). There was no significant correlation between v e and f, v e and D*, v e and f· D*, D* and K trans , and D* and k ep . The reproducibility of IVIM-MRI measurements was moderate. For parameter f, intraclass correlation coefficient (ICC) = 0.71 (0.53-0.82), coefficient of variation (CV) = 13.05 ± 0.02%, limit of agreement (LoA) = -0.05-0.04; for parameter D*, ICC = 0.55 (0.32-0.72), CV = 20.28 ± 3.23%, LoA = -9.6-8.4., Conclusion: Perfusion-sensitive parameters derived from IVIM-MRI correlated fairly to moderately with DCE-MRI in rectal cancer patients and showed moderate measurement reproducibility. IVIM-MRI supplements routine high-resolution MRI without contrast enhancement to provide information of tumor microcirculation.

Background: To evaluate the diagnostic performance of diffusion kurtosis imaging (DKI) for distinguishing different histopathological subtypes and grades of rectal carcinoma and to compare DKI with conventional diffusion-weighted imaging (DWI)., Methods: This prospective study involved 132 patients with rectal carcinoma, comprising 116 with adenocarcinoma not otherwise specified (AC) and 16 with mucinous carcinoma (MC). High spatial resolution magnetic resonance (MR) and DKI sequences (b values of 0, 600, 1000, 1500 and 2000 s/mm 2 ) were performed for pretreatment evaluation. The mean kurtosis (MK) and mean diffusivity (MD) from DKI and the apparent diffusion coefficient (ADC) from DWI were measured by two experienced radiologists. The Mann-Whitney U test was used to evaluate different histopathological subtypes and grades. Receiver operating characteristic (ROC) curve analyses were performed to compare the diagnostic ability of different quantitative parameters., Results: The MD and ADC values were significantly higher for MC than for AC (1.94 ± 0.51 vs. 1.33 ± 0.02 and 1.26 ± 0.64 vs. 0.92 ± 0.01, respectively; P < 0.001). The MK values were significantly lower for MC than for AC (0.66 ± 0.02 vs. 0.93 ± 0.09, P < 0.001). The MK and MD values demonstrated higher sensitivity (94%, both) and specificity (96, 93%, respectively) than the ADC values. However, all the parameters derived from both DKI and DWI showed no significant differences between different histological grades., Conclusions: DKI is a more valuable imaging biomarker than conventional DWI for differentiating MC from AC. However, it is still debatable whether DKI is useful for distinguishing different histological grades.

Objective: The aim of this study was to discriminate metastatic from nonmetastatic regional lymph nodes (LNs) with short-axis diameters of less than 5 mm in rectal cancer using quantitative parameters derived from dynamic contrast-enhanced (DCE) MRI., Subjects and Methods: Sixty-five LNs from 122 patients were evaluated, including malignant LNs (n = 27) and benign LNs (n = 38). The following parameters were assessed: the forward volume transfer constant (K trans ), reverse volume transfer constant (k ep ), fractional extravascular extracellular space volume (Ve), short-axis diameter, long-axis diameter, and short- to long-axis diameter ratio. ROC curves were used to analyze statistically significant parameters., Results: Metastatic LNs exhibited a lower K trans than did nonmetastatic LNs (p < 0.001), but the other parameters were not significantly different between the two groups. The AUC of the K trans was 0.732, with a 95% CI of 0.610-0.854, and the diagnostic cutoff value was 0.088 min -1 (sensitivity, 60.5%; specificity, 81.5%)., Conclusion: K trans had moderate diagnostic performance in assessing small regional LNs in rectal cancer and appears to be a useful predictor when distinguishing malignant LNs from benign LNs only by morphology is difficult.

Objective: To evaluate the diagnostic value of 3.0T high-resolution MRI in mesorectal lymph node metastasis of rectal cancer., Methods: The images and postoperative pathological data of patients with pathologically diagnosed rectal cancer who underwent prospective 3.0T two dimensional high-resolution MRI rectal examinations and surgery within two weeks after MRI examination at the First Affiliated Hospital, Sun Yat-sen University from November 2015 to November 2016 were retrospectively collected. Patients who received preoperative neoadjuvant therapy and those who did not undergo operation after MRI examination were excluded. The MRI sequences included high-resolution sagittal, coronal and oblique axial T2 weighted image (T2WI) (repetition time/echo time, 3000-4000 ms/77-87 ms; slice thickness/gap, 3 mm/0 mm; field of view, 18-22 cm). Two abdominal MRI radiologists independently assessed the morphology, margin, signal of all visible mesorectal nodes, measured their minor axes (three times for each radiologist) and gave estimation of the malignancy. The criteria of metastatic nodes on high-resolution MRI T2WI were nodes with irregular shape, ill-defined border and/or heterogeneous signal. The results of MRI diagnosis were compared with postoperative pathology. The sensitivity, specificity, accuracy, positive predictive value(PPV) and negative predictive value(NPV) of mesorectal nodes and nodes with different short-axis diameter ranges were calculated to evaluate the diagnostic efficiency of high-resolution MRI. Kappa statistics was used to evaluate the agreement for per node and for per patient between high-resolution MRI and pathological results. A Kappa value of 0-0.20 indicated poor agreement; 0.21-0.40 fair agreement; 0.41-0.60 moderate agreement; 0.61-0.80 good agreement; and 0.81-1.00 excellent agreement., Results: A total of 81 patients were enrolled in the retrospective cohort study, including 50 males and 31 females with age of (59.3±11.1) years. Histopathology showed 1 case of well differentiated adenocarcinoma, 63 of moderately differentiated adenocarcinoma, 9 of moderately to poorly differentiated adenocarcinoma, 2 of poorly differentiated adenocarcinoma, 3 of mucinous adenocarcinoma and 3 of tubulovillous adenocarcinoma. Histopathological staging showed 2 cases in T1 stage, 20 in T2 stage, 45 in T3 stage and 14 in T4 stage; 34 in N0 stage, 40 in N1 stage and 7 in N2 stage; 76 in M0 stage and 5 in M1 stage. A total of 377 nodes were included in the node-by-node evaluation, of which 168 (44.6%) nodes were metastatic from 58.0% (47/81) patients. The median short-axis diameter was 5.4(2.4-18.6) mm in metastatic nodes, which was significantly larger than 3.8 (2.0-8.7) mm in non-metastatic nodes[Z=10.586, P=0.000]. The sensitivity, specificity, accuracy, PPV and NPV were 74.4% (125/168), 94.7% (198/209), 85.7% (323/377), 91.9% (125/136) and 82.2% (198/241), respectively. The Kappa values between high-resolution MRI and histopathological diagnosis for node-by-node and patient-by-patient were 0.71 and 0.70 respectively, indicating good agreements. Fourteen nodes >10 mm were all metastatic. The results of high-resolution MRI for nodal status were consistent with the results of histopathological diagnosis, and the sensitivity, accuracy and PPV were all 100.0%. Among 124 nodes with short-axis diameter of 5-10 mm, 95 (76.6%) were metastatic, and the sensitivity, specificity, accuracy, PPV and NPV were 78.9% (75/95), 86.2% (25/29), 80.6% (100/124), 94.9% (75/79) and 55.6% (25/45), respectively. The agreement was fair (Kappa value 0.55) between high-resolution MRI and histopathological diagnosis. Among 239 nodes with short-axis diameter ≤5 mm, 59(24.7%) were metastatic, and the sensitivity, specificity, accuracy, PPV and NPV were 61.0% (36/59), 96.1%(173/180), 87.4%(209/239), 83.7%(36/43) and 88.3%(173/196), respectively. The agreement was good (Kappa value 0.63) between high-resolution MRI and histopathological diagnosis., Conclusion: Rectal high-resolution MRI has good diagnostic value for estimating metastatic mesorectal nodes by evaluating the morphology, margin and signal of nodes.

Background: To investigate the application value of fat-suppressed gadolinium-enhanced isotropic high-resolution 3D-GRE-T1WI in regional nodes with different short-axis diameter ranges in rectal cancer, especially in nodes ≤5 mm., Methods: Patients with rectal adenocarcinoma confirmed by postoperative histopathology were included, and all the patients underwent preoperative 3.0 T rectal magnetic resonance imaging (MRI) and total mesorectal excision (TME) within 2 weeks after an MR scan. The harvested nodes from specimens were matched with nodes in the field of view (FOV) of images for a node-by-node evaluation. The maximum short-axis diameters of all the visible nodes in the FOV of images were measured by a radiologist; the morphological and enhancement characteristics of these nodes were also independently evaluated by two radiologists. The χ 2 test was used to evaluate differences in morphological and enhancement characteristics between benign and malignant nodes. The enhancement characteristics were further compared between benign and malignant nodes with different short-axis diameter ranges using the χ 2 test. Kappa statistics were used to describe interobserver agreement., Results: A total of 441 nodes from 70 enrolled patients were included in the evaluation, of which 111 nodes were metastatic. Approximately 85.5 and 95.6% of benign nodes were found to have obvious enhancement and homogeneous or mild-heterogeneous enhancement, respectively, whereas approximately 89.2 and 85.1% of malignant nodes showed moderate or mild enhancement and obvious-heterogeneous or rim-like enhancement, respectively. The area under the receiver operating characteristic (ROC) curve (AUC) values of the enhancement degree for identifying the overall nodal status, nodes ≤5 mm and nodes > 5 mm and ≤ 10 mm were 0.887, 0.859 and 0.766 for radiologist 1 and 0.892, 0.823 and 0.774 for radiologist 2, respectively. The AUCs of enhancement homogeneity were 0.940, 0.928 and 0.864 for radiologist 1 and 0.944, 0.938 and 0.842 for radiologist 2, respectively. Nodal border and signal homogeneity were also of certain value in distinguishing metastatic nodes., Conclusions: Enhancement characteristics based on fat-suppressed gadolinium-enhanced isotropic high-resolution 3D-GRE-T1WI were helpful for diagnosing metastatic nodes in rectal cancer and were a reliable indicator for nodes ≤5 mm.

BACKGROUND Comprehensive and precise assessment of rectal carcinoma is crucial before surgery to plan an individual treatment strategy. New functional techniques, such as intravoxel incoherent motion (IVIM), have emerged and could lead to more detailed information. The aim of this study was to evaluate the difference between the rectal tumor parenchyma and normal wall by IVIM and to explore the correlations of IVIM parameters and histopathology. MATERIAL AND METHODS We prospectively enrolled 128 patients with pathologically proven rectal non-mucinous carcinoma with differentiation degree and 16 patients with mucinous carcinoma. All patients underwent routine MR examination and IVIM sequence. The IVIM maps were automatically generated and 3 ROIs were drawn on the maximal rectal tumor parenchyma and normal rectal wall. The Wilcoxon signed rank test, t test, Mann-Whitney U test, and Spearman's rank correlation test were performed. RESULTS All IVIM parameters demonstrated the difference between rectal tumor parenchyma and normal wall (PD<0.001; PD*=0.014; Pf<0.001). Poorly differentiated carcinoma had a significantly lower f value (Pf=0.049) than well/moderately-differentiated carcinoma. In addition, mucinous carcinoma had a higher D (PD=0.001) and a lower D* value (PD*=0.001) than non-mucinous carcinoma. Correlation analysis between IVIM parameters and histopathology showed that D (|r|=0.538, PD=0.000) and D* (|r|=0.267, PD*=0.001) had statistically significant correlations with histological type and f (|r|=0.175, Pf=0.048) was significantly correlated with differentiation degree. CONCLUSIONS The IVIM parameters of rectal tumor parenchyma and normal wall were significantly different. D appears to be a valid and promising parameter to indicate histological features of rectal carcinoma.

The aim of the present study was to investigate the role of cortactin in the infiltrative behavior of glioma cells and the potential mechanism of cortactin in promoting the migration and invasion of glioma cells. The expression of cortactin was detected by immunohistochemistry in 40 human glioma specimens and 8 non-tumor brain specimens. U251, LN229 and SNB19 glioma cells were employed for the in vitro study and assigned into the siRNA-cortactin (transfected with siRNA specific to cortactin), siRNA-NC (transfected with negative control RNA sequence) and siRNA-N (transfected with empty vector) groups. The expression of cortactin in different treated glioma cell groups was detected using western blot analysis and RT-qPCR. The migration and invasion of glioma cells under different treatments were assessed using a wound-healing assay and Transwell-chamber invasion assay, respectively. The lamellipodia of glioma cells following treatment were observed by immunofluorescence (IF) and changes of lamellipodia over time were imaged using an inverted microscope. The distribution of cortactin and the actin-related protein 2/3 (Arp2/3) complex in glioma cells were observed after IF detection. The expression of cortactin in the glioma specimens was significantly higher than that in non-tumor brain tissue (P<0.05) and positively correlated with the malignancy of glioma specimens (r=0.912, P=0.00). The cortactin expression in glioma cells was markedly inhibited (P<0.05) and their migration and invasion ability was also impaired significantly following treatment with siRNA (P<0.05) compared with the other two groups. The size and persistence time of lamellipodia were reduced after cortactin expression was inhibited in glioma cells. Cortactin and the Arp2/3 complex were co-localized in the front of glioma cells, where actin was polymerized and lamellipodia formed. Thus, the results revealed that, cortactin is crucial in invasion and migration of glioma cells, which may promote the migration and invasion of glioma cells by regulating lamellipodia formation, a process requiring the combination of cortactin and the Arp2/3 complex.

Background and Purpose: Antiplatelet therapy is widely used for the primary or secondary prevention of stroke. Drugs like clopidogrel have emerged as alternatives for traditional antiplatelet therapy, and dual therapy with clopidogrel and aspirin is of particular interest. We conducted this meta-analysis to systematically review studies about dual therapy comparing monotherapy with aspirin alone., Methods: Randomized controlled trials were searched in PubMed (1966-May, 2015), EMBASE (1947-May, 2015), the Cochrane Central Register of Controlled Trials (CENTRAL) (1948-May, 2015), WHO International Clinical Trial (ICTRP) (2004-May, 2015), China Biology Medicine disc (CBM disc) (1978-May, 2015) and were included into the final analysis according to the definite inclusion criteria mentioned in the study selection section. Risk ratio (RR) was pooled with 95% confidence interval (CI) for dichotomous data. The heterogeneity was considered significant if the χ2 test was significant (P value < 0.10) or the I2 > 50.00%. Subgroup analyses were carried out on the long and short time periods, the race and region., Results: We included 5 studies involving 24,084 patients. A pooled analysis showed that dual therapy with clopidogrel and aspirin had a lower stroke incidence than monotherapy in both the short term and long term (RR = 0.69, 95% CI: 0.59-0.82, P <0.05; RR = 0.84, 95% CI: 0.72-0.98, P = 0.03, respectively). With regard to safety, dual therapy had a higher risk of bleeding than monotherapy for both periods (RR = 1.51, 95% CI: 1.03-2.23, P = 0.04; RR = 1.54, 95% CI: 1.32-1.79, P<0.05, respectively)., Conclusions: Dual therapy with clopidogrel and aspirin could be a preferable choice to prevent stroke in patients who have had a previous stroke or transient ischemic attack, as well as those who are at high risk for stroke. And the effect of dual therapy seems to be more obvious for short-term. However, it is associated with a higher risk of bleeding.

Background: Pleomorphic xanthoastrocytoma (PXA) is a rare and special type of astrocytoma which occurs in childhood and adolescence, and usually with a favorable prognosis. Since its initial description, PXA cases have been reported infrequently in the literature, mostly as single cases or small series., Purpose: To review the imaging characteristics of PXA., Material and Methods: MR imaging findings of 19 pathologically confirmed PXAs were retrospectively analyzed and correlated with the clinical and pathological features., Results: The clinical presentation in 18 patients included: dizziness (8); headache (9); and epilepsy (8). One patient was asymptomatic. On MR imaging, the tumors were located in the brain surface (17), thalamus (1) or deep in the right frontal lobe (1). The tumors were cystic (4), mixed cystic-solid (7), or solid (8) with well-defined (11) or poorly-defined borders (8). Peritumoral edema was marked (8), mild (9) or absent (2). Cystic components of tumors were hypointense on T1- and hyperintense on T2-weighted images whereas the solid components of tumors were hypointense or isointense on T1- and slightly hyperintense on T2-weighted images. There was marked (10), moderate (7) or no (2) contrast enhancement in the solid tumors with surrounding leptomeningeal enhancement (7). The tumors were located in the frontal lobes (8), temporal lobes (7), occipital lobe (1), cerebellum (1), thalamus (1), and sellar region (1). Histologically, 18 tumors were classified as WHO grade 2 comprising of pleomorphic giant cells, spindle cells and foamy cells. One PXA with anaplastic features was composed of pleomorphic polygonal cells and spindle cells, and with high mitotic activity ( ≥5 mitoses per 10 HPF). Immunohistochemical reactions to glial fibrillary acidic protein (GFAP) were positive in all 19 cases., Conclusion: The pathological appearances of PXA are distinctive. MR imaging could display the morphologic features exactly, and has important diagnostic value for PXA.

Objective: To assess a new intervention for reestablishing the second hepatic hilum by means of puncturing and stenting the liver tissue between the intrahepatic vena cava and a hepatic vein for the treatment of Budd-Chiari syndrome (BCS)., Methods: Two patients with BCS, in which no second hepatic hilum structure was found in transhepatic venography, underwent an interventional procedure of canalizing and stenting the parenchyma tract between the intrahepatic vena cava and a hepatic vein. The procedures were performed in the percutaneous transhepatic and right jugular vein, respectively. A metallic stent with a 10 mm diameter was implanted to maintain tract patency., Results: The free hepatic vein pressure (FHVP) of both patients decreased from 37 mm Hg to 5 mm Hg and from 28 mm Hg to 4 mm Hg, respectively, after the procedure. The complication of hemorrhage due to puncture was observed in one patient. Both patients maintained hepatic improvements in 3-year follow-up. Both clinical conditions and laboratory values were significantly improved after the procedure. Furthermore, the stented canals (the reestablished second hepatic hilum) maintained patent with normal FHVP, which was confirmed by control venography., Conclusion: The new technique provides a simple, safe, effective, and relatively inexpensive treatment of Budd-Chiari syndrome. Long-lasting effectiveness is expected.