Abdominal multi-organ segmentation in Multi-sequence MRIs based on visual attention guided network and knowledge distillation.

PURPOSE: The segmentation of abdominal organs in magnetic resonance imaging (MRI) plays a pivotal role in various therapeutic applications. Nevertheless, the application of deep-learning methods to abdominal organ segmentation encounters numerous challenges, especially in addressing blurred boundaries and regions characterized by low-contrast. METHODS: In this study, a multi-scale visual attention-guided network (VAG-Net) was proposed for abdominal multi-organ segmentation based on unpaired multi-sequence MRI. A new visual attention-guided (VAG) mechanism was designed to enhance the extraction of contextual information, particularly at the edge of organs. Furthermore, a new loss function inspired by knowledge distillation was introduced to minimize the semantic disparity between different MRI sequences. RESULTS: The proposed method was evaluated on the CHAOS 2019 Challenge dataset and compared with six state-of-the-art methods. The results demonstrated that our model outperformed these methods, achieving DSC values of 91.83 ± 0.24% and 94.09 ± 0.66% for abdominal multi-organ segmentation in T1-DUAL and T2-SPIR modality, respectively. CONCLUSION: The experimental results show that our proposed method has superior performance in abdominal multi-organ segmentation, especially in the case of small organs such as the kidneys.

Evaluation of three-dimensional dual-energy CT cholangiopancreatography image quality in patients with pancreatobiliary dilatation: Comparison with conventional single-energy CT.

Objective: This study aimed to evaluate three-dimensional (3D) negative-contrast CT cholangiopancreatography (nCTCP) image quality using dual-energy CT (DECT) with iterative reconstruction (IR) technique in patients with pancreatobiliary dilatation compared with single-energy CT (SECT). Methods: Of the patients, 67 and 56 underwent conventional SECT (SECT set) and DECT with IR technique (DECT set), respectively. All patients were retrospectively analyzed during the portal phase to compare objective image quality and other data including patient demographics, hepatic and pancreatic parenchymal enhancement, noise, and attenuation difference (AD) between dilated ducts and enhanced hepatic parenchyma, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and CT volume dose index (CTDIvol). Two radiologists used the five-point Likert scale to evaluate the subjective image quality of 3D nCTCP regarding image noise, sharpness of dilated ducts, and overall image quality. Statistical analyses used the Mann-Whitney U test. Results: No significant difference in patient demographics in either CT set was showed during objective evaluation (p > 0.05). However, higher hepatic and pancreatic parenchymal enhancement, AD, SNR, and CNR and lower hepatic and pancreatic noise (p < 0.005) as well as CTDIvol (p = 0.005) on DECT than on SECT were observed. Higher mean grades on DECT than on SECT were showed for image noise (4.65 vs 3.92), sharpness of dilated ducts (4.52 vs 3.94), and overall image quality (4.45 vs 3.91; p < 0.001), respectively during subjective evaluation. Conclusion: A higher overall image quality and lower radiation dose on 3D nCTCP can be obtained by DECT with IR technique than with conventional SECT in patients with pancreatobiliary dilatation.

Preoperative evaluation of malignant pancreatobiliary obstruction: A novel technique for multiphase fusion 3D CT images.

The purpose of this article is to describe a novel technique of multiphase fusion three-dimensional (3D) images in patients with malignant pancreatobiliary obstruction. Multiphase fusion 3D images of CT arteriography, portovenography and hepatic venography combined with negative-contrast CT cholangiopancreatography can be done with enhanced multiphase CT scan using intravenous contrast agent at once. This technique may be feasible for one-stop evaluation of malignant pancreatobiliary obstruction.

Adding liver R2* quantification to proton density fat fraction MRI of vertebral bone marrow improves the prediction of osteoporosis.

OBJECTIVES: To assess the predictive value of the combination of bone marrow (BM) proton density fat fraction (PDFF) and liver R2* for osteopenia and osteoporosis and the additional role of liver R2*. METHODS: A total of 107 healthy women were included between June 2019 and January 2021. Each participant underwent dual-energy X-ray absorptiometry (DXA) and chemical shift-encoded 3.0-T MRI. PDFF measurements were performed for each lumbar vertebral body, and R2* measurements were performed in liver segments. Agreement among measurements was assessed by Bland-Altman analysis. Receiver operating characteristic (ROC) curves were generated to select optimised cut-offs for BM PDFF and liver R2*. Univariable and multivariable logistic regressions were performed. The C statistic and continuous net reclassification improvement (NRI) were adopted to explore the incremental predictive ability of liver R2*. RESULTS: Bone mass decreased in 42 cases (39.3%) and nonbone mass decreased in 65 cases (60.7%). There were significant differences among the age groups, menopausal status groups, PDFF > 45.0% groups, and R2* > 67.7 groups. Each measurement had good reproducibility. The odds ratios (95% CIs) were 4.05 (1.22-13.43) for PDFF and 4.34 (1.41-13.35) for R2*. The C statistic (95% CI) without R2* was 0.888 (0.827-0.950), and with R2* was 0.900 (0.841-0.960). The NRI resulting from the combination of PDFF and R2* was 75.6% (p < 0.01). CONCLUSION: The predictive improvement over the use of BM PDFF and other traditional risk factors demonstrates the potential of liver R2* as a biomarker for osteopenia and osteoporosis in healthy women. KEY POINTS: • Liver R2* is a biomarker for the assessment of osteopenia and osteoporosis. • Liver R2* improved the ability to predict osteopenia and osteoporosis. • The intra- and interobserver measurements showed high agreement.

CT Super-Resolution GAN Constrained by the Identical, Residual, and Cycle Learning Ensemble (GAN-CIRCLE).

In this paper, we present a semi-supervised deep learning approach to accurately recover high-resolution (HR) CT images from low-resolution (LR) counterparts. Specifically, with the generative adversarial network (GAN) as the building block, we enforce the cycle-consistency in terms of the Wasserstein distance to establish a nonlinear end-to-end mapping from noisy LR input images to denoised and deblurred HR outputs. We also include the joint constraints in the loss function to facilitate structural preservation. In this process, we incorporate deep convolutional neural network (CNN), residual learning, and network in network techniques for feature extraction and restoration. In contrast to the current trend of increasing network depth and complexity to boost the imaging performance, we apply a parallel 1×1 CNN to compress the output of the hidden layer and optimize the number of layers and the number of filters for each convolutional layer. The quantitative and qualitative evaluative results demonstrate that our proposed model is accurate, efficient and robust for super-resolution (SR) image restoration from noisy LR input images. In particular, we validate our composite SR networks on three large-scale CT datasets, and obtain promising results as compared to the other state-of-the-art methods.

Clinical Value of Multi-Slice Spiral CT Angiography, Colon Imaging, and Image Fusion in the Preoperative Evaluation of Laparoscopic Complete Mesocolic Excision for Right Colon Cancer: a Prospective Randomized Trial.

PURPOSE: To evaluate the clinical value of CT angiography (CTA), CT colonography (CTC), and image fusion in the preoperative evaluation of laparoscopic complete mesocolic excision (CME) for right colon cancer. METHODS: In this randomized prospective study, 80 patients undergoing laparoscopic CME for right colon cancer were randomly divided into two groups: image fusion [the original images were reconstructed using CTA and CTC, then fused into three-dimensional images of the blood vessels and intestines (n = 40)] and control (without CTA and CTC reconstruction before surgery). All patients underwent plain and enhanced abdominal CT before surgery. RESULTS: In the image fusion group, the gastrocolic trunk of Henle was present in 33 cases, and its branches originated from the colon vein, right gastroepiploic vein, and superior anterior pancreaticoduodenal vein. Among these patients, 5 exhibited the right gastroepiploic vein and superior anterior pancreaticoduodenal vein; 21 exhibited a gastrointestinal trunk consisting of 2 or 3 branches of the right gastroepiploic vein, right colon vein, and middle colon vein; and 7 exhibited 3 or 4 gastro-pancreatic and colon trunks consisting of the right colon vein, middle colon vein, right gastroepiploic vein, and superior anterior pancreaticoduodenal vein. The correspondence with the anatomy actually observed during surgery was 100%. Compared with the conventional CT group, the duration of the operation in the image fusion group was shorter, with reduced intraoperative bleeding, and more lymph node dissection. There were no significant differences in the incidence of complications and length of hospital stay between the two groups (p > 0.05). CONCLUSIONS: For laparoscopic CME for right colon cancer, CTA, CTC, and image fusion were effective preoperative evaluation methods, which avoided some unseen dangers in the operation process and led to better therapeutic outcomes.

Structurally-sensitive Multi-scale Deep Neural Network for Low-Dose CT Denoising.

Computed tomography (CT) is a popular medical imaging modality and enjoys wide clinical applications. At the same time, the x-ray radiation dose associated with CT scannings raises a public concern due to its potential risks to the patients. Over the past years, major efforts have been dedicated to the development of Low-Dose CT (LDCT) methods. However, the radiation dose reduction compromises the signal-to-noise ratio (SNR), leading to strong noise and artifacts that downgrade CT image quality. In this paper, we propose a novel 3D noise reduction method, called Structurally-sensitive Multi-scale Generative Adversarial Net (SMGAN), to improve the LDCT image quality. Specifically, we incorporate three-dimensional (3D) volumetric information to improve the image quality. Also, different loss functions for training denoising models are investigated. Experiments show that the proposed method can effectively preserve structural and textural information in reference to normal-dose CT (NDCT) images, and significantly suppress noise and artifacts. Qualitative visual assessments by three experienced radiologists demonstrate that the proposed method retrieves more information, and outperforms competing methods.

Diffusion-weighted magnetic resonance imaging reflects activation of signal transducer and activator of transcription 3 during focal cerebral ischemia/reperfusion.

Signal transducer and activator of transcription (STAT) is a unique protein family that binds to DNA, coupled with tyrosine phosphorylation signaling pathways, acting as a transcriptional regulator to mediate a variety of biological effects. Cerebral ischemia and reperfusion can activate STATs signaling pathway, but no studies have confirmed whether STAT activation can be verified by diffusion-weighted magnetic resonance imaging (DWI) in rats after cerebral ischemia/reperfusion. Here, we established a rat model of focal cerebral ischemia injury using the modified Longa method. DWI revealed hyperintensity in parts of the left hemisphere before reperfusion and a low apparent diffusion coefficient. STAT3 protein expression showed no significant change after reperfusion, but phosphorylated STAT3 expression began to increase after 30 minutes of reperfusion and peaked at 24 hours. Pearson correlation analysis showed that STAT3 activation was correlated positively with the relative apparent diffusion coefficient and negatively with the DWI abnormal signal area. These results indicate that DWI is a reliable representation of the infarct area and reflects STAT phosphorylation in rat brain following focal cerebral ischemia/reperfusion.

Noninvasive detection of matrix metalloproteinase-9 in atherosclerotic lesions using technetium-99m-labeled single-photon emission computed tomography in vivo.

OBJECTIVE: Previous studies have suggested that matrix metalloproteinase (MMP) inhibitor uptake may offer a precise estimation of MMP activity in atherosclerotic lesions. In this study, we explored the feasibility of noninvasive detection of MMP-9 activity using technetium-99m-labeled matrix metalloproteinase-9 antibody (Tc-McAb) in vivo. METHODS: ApoE-deficient (ApoE) atherosclerosis mice models (n=10) were induced through a high-cholesterol diet following ligation of their left common carotid artery. After 4 weeks, the models were verified through proton density-weighted and T2-weighted images obtained by MRI. C57BL/6 sham mice (n=8) were used as controls. In addition, normal mice (n=20) were used to characterize blood clearance. After radiolabeled McAb administration, single-photon emission computed tomography (SPECT) was performed. Subsequently, left common carotid arteries were harvested for ex-vivo autoradiograph imaging. Then, morphology and activity assays of MMP-9 were histologically and immunohistochemically examined. RESULTS: MRI showed higher signal intensities in the left common carotid arteries with irregular stenoses in the lumen of blood vessels in atherosclerosis mice models in vivo. Atherosclerotic lesions on left common carotid artery specimens were also clearly visualized using SPECT 2 h after Tc-McAb administration in vivo. Note that the radiochemistry purity of the Tc-McAb used was 85-95%. Biodistribution studies have shown that the clearance of Tc-McAb from blood was rapid. In addition, atherosclerotic lesions were clearly visualized on radioautography film shadows ex vivo. CONCLUSION: MMP-9 activities within the atherosclerotic lesions were noninvasively detected using Tc-labeled SPECT in vivo.

Prediction of Vascular Invasion Using a 3-Point Scale Computed Tomography Grading System in Pancreatic Ductal Adenocarcinoma: Correlation With Surgery.

OBJECTIVE: The aim of this study was to evaluate the correlation between a 3-point scale multidetector computed tomography (MDCT) grading system and surgical exploration in predicting vascular invasion and resectability in patients with pancreatic ductal adenocarcinoma (PDA). METHODS: Fifty-five patients with surgical and pathologic confirmation of PDA were retrospectively analyzed by 3 radiologists independently. All patients had MDCT examination with multiplanar reformatted images, computed tomography (CT) angiography, and negative-contrast CT cholangiopancreatography (nCTCP). A 3-point scale CT grading system and criteria for unresectability adopting the latest guidelines were used in predicting the correlation between the invasion and resectability of 5 peripancreatic vessels and surgical grade and pathology. RESULTS: Tumor location was correctly identified in all patients including 2 isodense lesions by means of nCTCP. The mean sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of MDCT were 92%, 83%, 95%, 78%, and 90%, respectively, in predicting tumor resectability compared with surgery and pathology and with good agreement (κ = 0.72-0.77). A correlation was observed between CT and surgical grade in predicting vascular invasion on a per-vessel basis, and the agreement presented as good to excellent (κ = 0.66-1.00). CONCLUSIONS: A 3-point scale CT grading system is a simple and practical method in predicting peripancreatic vessel invasion and, importantly, correlates with surgical grade and pathology. Axial images combined with multiplanar reformation, nCTCP, and CT angiography can strengthen the comprehensive evaluation of PDA for resectability.

Erythropoietin reduces apoptosis of brain tissue cells in rats after cerebral ischemia/reperfusion injury: a characteristic analysis using magnetic resonance imaging.

Some in vitro experiments have shown that erythropoietin (EPO) increases resistance to apoptosis and facilitates neuronal survival following cerebral ischemia. However, results from in vivo studies are rarely reported. Perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) have been applied successfully to distinguish acute cerebral ischemic necrosis and penumbra in living animals; therefore, we hypothesized that PWI and DWI could be used to provide imaging evidence in vivo for the conclusion that EPO could reduce apoptosis in brain areas injured by cerebral ischemia/reperfusion. To validate this hypothesis, we established a rat model of focal cerebral ischemia/reperfusion injury, and treated with intra-cerebroventricular injection of EPO (5,000 U/kg) 20 minutes before injury. Brain tissue in the ischemic injury zone was sampled using MRI-guided localization. The relative area of abnormal tissue, changes in PWI and DWI in the ischemic injury zone, and the number of apoptotic cells based on TdT-mediated dUTP-biotin nick end-labeling (TUNEL) were assessed. Our findings demonstrate that EPO reduces the relative area of abnormally high signal in PWI and DWI, increases cerebral blood volume, and decreases the number of apoptotic cells positive for TUNEL in the area injured by cerebral ischemia/reperfusion. The experiment provides imaging evidence in vivo for EPO treating cerebral ischemia/reperfusion injury.

[Comparative study of CT versus gross pathology in rabbit VX2 colorectal cancer model].

OBJECTIVE: To establish rabbit VX2 colorectal cancer(CRC) model and to compare CT images with gross pathology in order to offer help for TNM staging in patients with CRC. METHODS: VX2 tumor pieces were implanted into colonic wall in 9 New Zealand white rabbits and rectal wall in 2 New Zealand white rabbits. Four weeks after inoculation, Ultravist(370 mg/ml) was injected through ear marginal vein with high pressure injector for stage 3 scanning of chest, abdomen and pelvis, and enhanced CT (collimation 0.5 mm mm × 320, pitch factor 0.828, bulb rotation speed 0.5 s/cycle, 120 kV, automatic ma, range 80 to 100 mAs) was performed to determine the presence of CRC or metastasis once a week for 4-6 weeks. Once inoculated CRC or metastases occurred or 6 weeks after implantation, the rabbits were sacrificed regardless of the presence or absence of CRC or metastasis on the CT images. One rabbit was used for gross anatomy observation. Others were placed in wood boxes with -80centi-degree for 24 hours, then samples of 3 mm thickness were cut using a motorized saw to make macropathology. Each cutting surface of the specimens was photographed in serial number. If certain or suspected lesions were found on the slices, such part was labeled and then placed in 10% phosphate-buffered formaldehyde numbered box for subsequent pathological examination. CT image postprocessing was performed referring to the gross slice specimens and all findings were compared with the pathological reports. RESULTS: Among 11 rabbits, tumor was successfully established in 8 rabbits. Pathology showed that single lung metastasis (7 to 10 mm) was found in 2 rabbits and liver metastasis (9 mm) in 1 rabbit. Number of lymph node located around the inoculated tumor was 22 and that around mesenteric vessels was 13 with diameter of 2 to 16 mm. Among these 35 lymph nodes from 8 successful rabbits, 9 nodes were positive, including 7 around inoculated tumor and 2 around mesenteric vessels. CT identified above 8 primary inoculated tumors, 2 lung metastatic lesions and 1 liver metastatic lesion, with detection rate of 100%. For the detection of lymph node in CT, 27 nodes were identified in the pericolorectal region (17 nodes) and perimesenteric vessels (10 nodes), in which 6 were positive metastasis (ring-shaped enrichment and central low density necrosis), resulting in a detection rate of 77.1%(27/35 nodes), and positive detection rate of 66.7% (6/9 nodes), respectively. CONCLUSION: Living rabbit CT-gross pathological slice(3 mm-cut) of VX2 CRC model can be applied in image evaluation of small metastatic lesion.

Presurgical Evaluation of Pancreatic Cancer: A Comprehensive Imaging Comparison of CT Versus MRI.

OBJECTIVE: The purpose of this study was to compare comprehensive CT and MRI in the presurgical evaluation of pancreatic cancer. MATERIALS AND METHODS: Thirty-eight patients with pathologically proven pancreatic cancer were included in a retrospective study. CT with negative-contrast CT cholangiopancreatography and CT angiography (CTA) (CT image set) versus MRI with MRCP and MR angiography (MRI image set) were analyzed independently by two reviewers for tumor detection, extension, metastasis, vascular invasion, and resectability. These results were compared with the surgical and pathologic findings. RESULTS: The rate of detection of tumors was higher with MRI than with CT but not significantly so (reviewer 1, p = 1.000; reviewer 2, p = 0.500). In the evaluation of vessel involvement, nodal status, and resectability, although CT had higher ROC AUC values than did MRI (reviewer 1, 0.913 vs 0.858, 0.613 vs 0.503, and 0.866 vs 0.774; reviewer 2, 0.879 vs 0.849, 0.640 vs 0.583, and 0.830 vs 0.815), the differences were not statistically significant (p = 0.189 vs 0.494, 0.328 vs 0.244, and 0.193 vs 0.813 for reviewers 1 and 2). In the evaluation of tumor extension and organ metastases in the 38 patients, correct diagnosis of one of two liver metastases was achieved with both image sets, one case of omental and one case of peritoneal seeding were underestimated, and one case of stomach invasion was overestimated. CONCLUSION: MRI and CT had similar performance in the presurgical evaluation of pancreatic cancer.

Preoperative Evaluation of Malignant Perihilar Biliary Obstruction: Negative-Contrast CT Cholangiopancreatography and CT Angiography Versus MRCP and MR Angiography.

OBJECTIVE: The purpose of this study was to compare negative-contrast CT cholangiopancreatography (CTCP) and CT angiography (CTA) with MRCP and MR angiography (MRA) for the preoperative evaluation of malignant perihilar biliary obstruction. MATERIALS AND METHODS: Twenty-one patients with pathologically proven malignant perihilar biliary obstructions who had undergone both CT and MRI examinations were reviewed retrospectively. Two reviewers independently analyzed the two image sets-the negative-contrast CTCP and CTA images (i.e., CT set) and the MRCP and MRA images (i.e., MRI set)-in preoperatively evaluating the classification of malignant perihilar biliary obstruction, hepatic artery and portal vein invasion, nodal metastasis, and organ spread. The results were compared with surgical and pathologic records. RESULTS: For the classification of malignant perihilar biliary obstruction on the two image sets, the accuracy was not statistically significant (p = 1.000 for reviewer 1 and p = 0.500 for reviewer 2). For the evaluation of portal vein invasion, nodal metastasis, and organ spread, the accuracies were also not statistically significantly different (p = 0.335, 0.339, and 0.781 for reviewer 1; and p = 0.403, 0.495, and 0.325 for reviewer 2, respectively). In the assessment of hepatic artery status, the accuracy was statistically significant (p = 0.046 for reviewer 1 and p = 0.036 for reviewer 2). CONCLUSION: Compared with the MRI set, the CT set provides equivalent performance in assessing the classification of malignant perihilar biliary obstruction, portal vein involvement, nodal metastasis, and organ spread, but has higher accuracy in assessing arterial invasion.

Differentiation of noncalculous periampullary obstruction: comparison of CT with negative-contrast CT cholangiopancreatography versus MRI with MR cholangiopancreatography.

OBJECTIVES: The purpose of this study was to compare CT with negative-contrast CT cholangiopancreatography (nCTCP) using subvolume minimum intensity projection (MinIP) versus MRI with MRCP in differentiating noncalculous periampullary obstruction. METHODS: Sixty-four patients with clinically proven noncalculous periampullary obstructions who had undergone both MDCT and MR examinations before operation were reviewed retrospectively. Two reviewers independently interpreted the two image sets (the CT with nCTCP set [CT set] vs. the MRI with MRCP set [MRI set]) in differentiating both benign from malignant obstruction and pancreatic head carcinoma (PHC) from non-PHC, and the results were compared to the final clinical records. RESULTS: In this study, no statistically significant differences were observed in the accuracy of differentiating benign from malignant periampullary obstruction (p = 0.754 for reviewer 1 and p = 0.508 for reviewer 2) on the two image sets. The accuracy of differentiating PHC from non-PHC was also statistically insignificant (p = 0.125 for reviewer 1 and p = 1.000 for reviewer 2) on the two image sets. CONCLUSION: The CT set provides a comparable performance to that of the MRI set in differentiating noncalculous periampullary obstruction. KEY POINTS: • nCTCP with subvolume MinIP is a practical tool in evaluating biliary obstruction • Two image sets have a comparable performance in differentiating noncalculous periampullary obstruction • MDCT could serve as an alternative in patients not eligible for MRI.

Differential diagnosis of periampullary carcinomas: comparison of CT with negative-contrast CT cholangiopancreatography versus MRI with MR cholangiopancreatography.

BACKGROUND: Negative-contrast CT cholangiopancreatography (nCTCP) has been introduced into clinical practice recently. In the present study, we compared CT with nCTCP vs. MRI with MR cholangiopancreatography (MRCP) for the differential diagnosis of periampullary carcinomas. METHODS: Fifty-nine patients with pathologically proven periampullary carcinomas who had received both CT and MR examinations before operation were reviewed retrospectively. Two reviewers independently interpreted the two image sets [the two-dimensional (2D)-CT with nCTCP set (CT set) vs. the 2D-MRI with MRCP set (MRI set)] in differentiating periampullary carcinomas, and the results were compared to the final pathologic records. RESULTS: An interobserver agreement with a weighed κ value of 0.868 for the CT set and 0.701 for the MRI set was obtained for both reviewers in this study. No statistically significant differences were observed in the accuracy of identifying each of the periampullary carcinomas of four origins (P values of 0.250, 0.500, 0.500, and 1.000 for reviewer 1 in comparison with 1.000, 0.625, 0.687, and 1.000 for reviewer 2 on the two image sets, respectively). CONCLUSION: The CT set provides a comparable performance to that of the MRI set in differentiating periampullary carcinomas, and it may be an alternative to 2D-MRI with MRCP in assessing malignant biliary obstruction in patients who are not suitable for MR examinations.

Effects of erythropoietin on STAT1 and STAT3 levels following cerebral ischemia-reperfusion in rats.

BACKGROUND AND PURPOSE: Cerebral ischemia-reperfusion injury can activate signal transducers and activators of transcription (STAT). STAT1 initiates neuronal apoptosis following cerebral ischemia-reperfusion, while STAT3 is neuroprotective. Erythropoietin (EPO) promotes regeneration through STAT3 and facilitates neuronal survival following ischemia. However, there are few reports on the effects of EPO on phosphorylated STAT1 (P-STAT1) level following cerebral ischemia-reperfusion in rats, and there is no evidence on the simultaneous observation of the four kinds of protein:STAT1, P-STAT1, STAT3, and P-STAT3. METHODS: We established a rat focal cerebral ischemia-reperfusion injury model, and used Western blot and immunohistochemical staining to assess the levels of STAT1 and STAT3 expression, and TdT-mediated dUTP-biotin nick end-labeling (TUNEL) was carried out to observe the number of apoptotic cells with or without EPO treatment. RESULTS: Our findings show that EPO treatment had no significant effect on STAT1 and STAT3 expression, but P-STAT1 and P-STAT3 were slightly decreased and significantly increased, respectively, after EPO treatment. Neurologic deficits, the infarct volume, and the number of apoptotic cells were significantly decreased after EPO treatment. CONCLUSIONS: The results suggest that EPO exerts a neuroprotective effect by influencing STAT3 and STAT1 expression in the area injured by cerebral ischemia-reperfusion.

Comparison of three-dimensional negative-contrast CT cholangiopancreatography with three-dimensional MR cholangiopancreatography for the diagnosis of obstructive biliary diseases.

PURPOSE: The purpose of our study was to compare three-dimensional (3D) negative-contrast CT cholangiopancreatography (3D-nCTCP) with 3D MR cholangiopancreatography (3D-MRCP) for the diagnosis of obstructive biliary diseases. MATERIALS AND METHODS: 3D-nCTCP and 3D-MRCP were performed on seventy clinically documented obstructive biliary diseases patients. The accuracy of each technique in determining the location and cause of biliary obstruction was evaluated compared with the final clinical diagnoses. RESULTS: Both methods achieved 100% of accuracy in the diagnosis of the presence and location of biliary obstruction, and had a similar sensitivity, specificity, accuracy in differentiating benign from malignant biliary obstruction or calculous from noncalculous biliary obstruction (p>0.05). At 3D-nCTCP, six patients with stones were misinterpreted as cholangitis (N=2), papillitis (N=3), or bile duct adenocarcinoma (N=1); two metastases were mistaken as acute pancreatitis or pancreatic head carcinomas, and one intrahepatic cholangiocarcinoma was misled as bile duct adenoma. At 3D-MRCP, one small stone, one ampullary adenoma, and one intrahepatic cholangiocarcinoma were mistaken as cholangitis, ampullary stone, and intrahepatic bile duct stone, respectively, and three gallbladder carcinomas and another intrahepatic cholangiocarcinoma were misdiagnosed as hilar cholangiocarcinoma (N=3) or common hepatic duct stone (N=1); four metastases were mistaken as pancreatic head carcinomas (N=3) or distal cholangiocarcinoma (N=1). The overall accuracy in making specific diagnosis of the cause of biliary obstruction was 87.1% for 3D-nCTCP and 84.3% for 3D-MRCP, respectively, (p>0.05). CONCLUSION: 3D-nCTCP has the similar effects as 3D-MRCP for the diagnosis of biliary obstruction and, the location and the cause of biliary obstruction. In view of selected cases contraindications for MRI, 3D-nCTCP is a potential substitute.

Improvement in imaging time and quality of 3D negative-contrast computed tomography cholangiography with minimum intensity projections: application of vari-slice manual cut and erosion functions.

OBJECTIVE: To investigate the improvement in postprocessing time and image quality of 3D negative-contrast CT cholangiography (nCTC) with minimum intensity projection (minIP). METHODS: Thirty-eight patients with suspected biliary obstruction who underwent portal phase helical CT were retrospectively studied. Three-dimensional nCTC was generated using 3D tools with manual cut function in three methods: one-slice, two-slice, and vari-slice cut slab, respectively. After adjusting the threshold level to about -20 HU, the erosion function with a value of one voxel was employed each time for further cleaning up hypodense interfering voxels such as fat and air that remained and the procedure was stopped before the biliary and pancreatic ducts were overeroded. RESULTS: Mean values of the total postprocessing time of the three manual cut methods for 3D nCTC were 57.8, 29.9, and 20.6 min, respectively. After the first erosion, interfering voxels were removed in more than half of the cases and they could be primarily eliminated following the second erosion. Meanwhile, the pancreaticobiliary ducts showed obvious erosion findings at the third erosion. CONCLUSIONS: The vari-slice manual cut method was shown to be the most timesaving postprocessing method and the image quality for 3D nCTC can be improved when one to two frequencies of erosion are applied.