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find Keyword "Contrast" 33 results
  • Small bowel video keyframe retrieval based on multi-modal contrastive learning

    Retrieving keyframes most relevant to text from small intestine videos with given labels can efficiently and accurately locate pathological regions. However, training directly on raw video data is extremely slow, while learning visual representations from image-text datasets leads to computational inconsistency. To tackle this challenge, a small bowel video keyframe retrieval based on multi-modal contrastive learning (KRCL) is proposed. This framework fully utilizes textual information from video category labels to learn video features closely related to text, while modeling temporal information within a pretrained image-text model. It transfers knowledge learned from image-text multimodal models to the video domain, enabling interaction among medical videos, images, and text data. Experimental results on the hyper-spectral and Kvasir dataset for gastrointestinal disease detection (Hyper-Kvasir) and the Microsoft Research video-to-text (MSR-VTT) retrieval dataset demonstrate the effectiveness and robustness of KRCL, with the proposed method achieving state-of-the-art performance across nearly all evaluation metrics.

    Release date:2025-04-24 04:31 Export PDF Favorites Scan
  • Application of Contrast-Enhanced Ultrasonography in Differential Diagnosis of Retroperitoneal Occupying Lesions

     Objective To evaluate the real-time contrast-enhanced ultrasonography (CEUS) in the differential diagnosis of retroperitoneal occupying lesions.  Methods Thirty patients with retroperitoneal occupying lesions, including 10 benign and 20 malignant lesions, were performed with CEUS, thus describing the perfusion of contrast agent, the entering style of contrast agent and the vascular morphous. And the entering styles were divided into two patterns: peripheral type or central type while the vascular morphous were divided into 4 levels: level 0, level 1, level 2 and level 3. All of these were compared between benign and malignant lesions. Compared the results of diagnosis malignant lesions by common ultrasonography with CEUS.  Results 1/5 case of benign substantive lesions presented as contrast agent perfusion defect, and 11/20 cases of substantive malignant lesions presented as contrast agent perfusion defect. 14/20 of malignant lesions were central type; 9/10 of benign lesions were peripheral type (P=0.005 2). In benign lesions, level 0 had 7/10, level 1 had 2/10 and level 3 had 1/10. In malignant lesions, level 0 had 1/20, level 1 had 3/20, level 2 had 8/20 and level 3 had 8/20, too (P=0.000 5). The rate of missed diagnosis was 40.00% and the accuracy was 66.67% by common ultrasonography, while the rate of missed diagnosis was 10.00% and the accuracy was 86.67% by CEUS combined with the entering style of contrast agent and the vascular morphous.  Conclusion The CEUS applies a new way to discriminate malignant from benign in retroperitoneal occupying lesions.

    Release date:2016-09-08 10:57 Export PDF Favorites Scan
  • Application of Contrast Enhanced Ultrasound in Sentinel Lymph Node Biopsy of Breast Cancer

    ObjectiveTo evaluate the diagnostic value of contrast enhanced ultrasound (CEUS) to the sentinel lymph node (SLN) of breast cancer. MethodsSeventy-two operable breast cancer patients with clinically negative axillary lymph node were enrolled.Sulphur hexafluoride microbubbles for injection (SonoVue) was used alone as the tracer agent for the sentinel lymph node biopsy (SLNB), and axillary dissection was performed after the methylene blue location.All SLNs were examined pathologically with HE staining.The SLN diagnosis result of contrast enhanced ultrasound and postoperative pathological examination result were comparative analyzed. ResultsAfter the injection of SonoVue can obtain a clear image of the lymphatic vessels and SLN.The success rate of CEUS imaging was 84.72% (61/72) in this group of 72 patients, and the false negative rate was 12.12% (4/33).The sensitivity and specificity of diagnosis by CEUS was 92.50% (37/40) and 92.59% (50/54), respectively, the diagnostic odds ratio (DOR) was 154.17.By the pathology results as the gold standard, the internal consistency of these two methods was good (Kappa value=0.848, P < 0.01). ConclusionCEUS may be a useful orientation and determination method for SLNs.

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  • Assessment of Short Term Therapeutic Response to Radiofrequency Ablation by Contrast Enhanced Ultrasound in Hepatocellular Carcinoma

    Objective To investigate the value of contrast enhanced ultrasound (CEUS) in evaluating the short term therapeutic response to radiofrequency ablation (RFA) of primary hepatocellular carcinoma. Methods One hundred and ten lesions were studied in 96 patients. Each patient underwent CEUS within a week before RFA, the number, size, border, inner echo and perfusion pattern of lesions were observed. One month after ultrasound-guided RFA, color Doppler flow imaging, CEUS and contrast enhanced computed tomography (CECT, reference standard) were performed to assess the therapeutic response. Results Before RFA, in 96 cases with 110 lesions, 83 lesions showed homogeneous hyper-enhancement and the other 27 heterogeneous hyper-enhancement in arterial phase, and 98 lesions were hypo-enhanced in portal venous phase and late phase and the other 12 iso-enhanced. One month after RFA, 99 of 110 lesions were found no-enhancement in entire CEUS procedure, while 11 lesions showed local enhancement on the edge of lesion. Ninety-six of 110 lesions showed no-enhancement and other 14 with irregular enhancement by CECT. There was no statistical significance between CEUS and CECT (χ2=0.406, Pgt;0.05). Fourteen lesions as tumor residual by CECT were underwent RFA again, and then 1 month after RFA no-enhancement was showed by both CECT and CEUS. Conclusion CEUS can play a role in assessing the short term therapeutic response to RFA of hepatocellular carcinoma.

    Release date:2016-09-08 10:57 Export PDF Favorites Scan
  • Value of Ultrasound Contrast Agents Injected Subcutaneously for Diagnosing Sentinel Lymph Nodes of Breast Cancer: A Meta-analysis

    ObjectiveTo systematically review the value of ultrasound contrast agents injected subcutaneously for diagnosing sentinel lymph nodes of breast cancer. MethodsWe electronically searched databases including PubMed, EMbase, The Cochrane Library, CNKI, CBM, WanFang Data, and Medalink from their inception to July 2014, to collect diagnostic accuracy studies of ultrasound contrast agents injected subcutaneously for diagnosing sentinel lymph nodes of breast cancer. Two reviewers independently screened literature according to the inclusion and exclusion criteria, extracted data and assessed the methodological quality of included studies. Then, meta-analysis was performed by using Meta-Disc 1.4 software. ResultsEight studies involving 311 sentinel lymph nodes were included. The results of meta-analysis showed that, the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and the area under curve (AUC) of SROC were 0.89 (95%CI 0.84 to 0.93), 0.81 (95%CI 0.72 to 0.87), 4.14 (95%CI 2.20 to 7.79), 0.15 (95%CI 0.10 to 0.25), 33.23 (95%CI 11.17 to 98.83), and 0.96 respectively. ConclusionContrast-enhanced ultrasound has a high value in diagnosis of sentinel lymph nodes of breast cancer. Due to limited quality and quantity of the included studies, more high quality and large-scale studies are needed to verify the above conclusion.

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  • Role of Contrast-Enhanced Ultrasonography in The Detection and Diagnosis of Small Primary Liver Cancer

    Objective To investigate the value of contrast-enhanced ultrasonography in detection and diagnosis of small primary liver cancer. Methods SonoVue-enhanced ultrasonography were performed on 353 patients with 378 primary liver cancer, less than 3 cm in diameter. Enhancement patterns and enhancement phases of hepatic lesions on contrast-enhanced ultrasonography were analyzed and compared with the results of histopathology. Results In all hepatic tumors, 96.6% (365/378) lesions enhanced in the arterial phase. Among them, 317 (83.9%) tumors enhanced earlier than liver parenchyma and 48 (12.7%) tumors enhanced synchronously with liver parenchyma, and 342 (90.5%) tumors showed early wash-out in the portal and late phases. With regard to the enhancement pattern, 329 (87.0%) tumors presented whole-lesion enhancement, 35 (9.3%) to be mosaic enhancement and 14 (3.7%) to be rim-like enhancement. If taking the whole-lesion enhancement and mosaic enhancement in arterial phase as diagnotic standard for primary liver cancer on contrast-enhanced ultrasonography, the sensitivity was 92.9%(351/378), and if the earlier or synchronous enhancement of the tumor compared with liver parenchyma in arterial phase and the wash-out in portal phase were regarded as the stardand, the sensitivity was 87.3%(330/378). Conclusion Contrast-enhanced ultrasonography could display real-time enhancement patterns as well as the wash-out processes both in hepatic tumors and the liver parenchyma. It might be of clinical value in diagnosis of primary liver cancer based on the hemodynamics of hepatic tumors on contrast-enhanced ultrasonography.

    Release date:2016-08-28 04:08 Export PDF Favorites Scan
  • Ultrasonic microbubble combined with bevacizumab injection for choroidal neovascularization induced by phtocoagulation in rabbits

    Objective  To observe the therapeutic effect of ultrasonic microbubble combined with bevacizumab (Avastin) on choroidal neovascularization induced by photocoagulation in rabbits.Methods CNV was induced by photocoagulation with argon laser in 30 rabbits (60 eyes).All of the rabbits underwent fundus fluorecein angiography (FFA) 21 days after photocoagulation; 6-8 hours later, 3 rabbits were randomly chosen to be executed to having the immunohistochemical examination.Twenty one days after photocoagulation, 27 rabbits were divided randomly into 3 groups: bevacizumb, ultrasonic microbubble + bevacizumb,and control group; each group has 9 rabbits (18 eyes).The rabbits in control group had no interference treatment; while the rats in bevacizumb and ultrasonic microbubble + bevacizumb group underwent injection with bevacizumb or ultrasonic microbubble + bevacizumb respectively.FFA was performed on all of the rabbits 7,14,and 28 days after photocoagulation to observe the inhibition of CNV; immunofluorecence and Western blot were used to detect the expression of VEGF in retina and choroid.Twentyeight days is the time point to determine the therapeutic efficacy. The expression of VEGF and the results of FFA were the sdandards of the judgement of therapeutic efficacy.Results Proliferaion of CNV to the retinal inner layer and the obvious leakage of fluoresein in the photocoagulation area indicated that the model of CNV was set up successfully. Twenty eight days after injection,obvious fluorescent leakage was found in the control group, and the average fluorescent leakage in bevacizumab group differed much from the control group(t=16.2952,Plt;0.05); while the difference between ultrasonic microbubble + bevacizumb group and bevacizumab group was also significant (t=4.7955,Plt;0.05) . At the same time point, the expression of VEGF in bevacizumab group detected by immunofluorecent assay and Western blot differed much from the control group (t=7.0327,9.2596;Plt;0.05),and the difference of VEGF between ultrasonic microbubble + bevacizumb group and bevacizumab group was significant(t=2.9724,17.1937;Plt;0.05). this experiment show that ultrasound combined bevacizumab intravitreal injection of the therapeutic effect of CNV superior to other groups(Plt;0.01).Conclusion Ultrasound microbubble combined with bevacizumab injection may improve the therapeutic effect on CNV by inhibiting the expression of VEGF.

    Release date:2016-09-02 05:40 Export PDF Favorites Scan
  • CONTRAST ANALYSIS OF DIFFERENT SAGITTAL SPLIT RAMUS OSTEOTOMY METHODS IN CORRECTING MADIBULAR PROGNATHISM

    Objective To explore the indication, advantage and disadvantage of modified or classical technique of intraoral sagittal split ramus osteotomy (SSRO) for correction of mandibular prognathism. Methods From January 1997 to January 2005, 95 patients suffering from mandibular prognathism or accompanied by other deformities were treated with modified or classical technique of intraoral SSRO. Of 95 cases, there were 34 males and 61 females, aging 15 to 44 years, including 53 cases of single mandibular prognathism, 28 cases accompanied with mandibular deviation, 11 cases accompanied with maxillaryretrognathism, 2 cases accompanied with glossacele and 1 case accompanied with malar protrution. X-ray cephalometry showed: sella-nasion-A point(SNA) 80-83°, sella-nasion-B point(SNB) 80-84°, A point-nasion-B point(ANB)-3-1°.Fortythree cases were corrected by modified SSRO and 52 cases by classical SSRO. Results The face appearance and dental articulation of all the patients were improved greatly. In patients by classical SSRO, disorder of local sensibility occurred in 9 cases, mandibular fracture during the cleavage ofthe ascending ramus in 1 case, significant bleeding in 1 case, postoperative infection in 1 case and postoperative relapse in 3 cases. In patients by modifiedSSRO, disorder of local sensibility occurred in 2 cases and postoperative relapse in 1 case; no mandibular fracture, significant bleeding, postoperative infection and other complications occurred. With a follow-up of 3 months to 7 years, X-ray cephalometry showed SNA 81-83°, SNB 78-81°and ANB 1-4°. 〖WTHZ〗Conclusion Modified SSRO is an ideal method of correcting mandibular prognathism, especially severer mandibularprognathism accompanied by mandible deviation deformity. 

    Release date:2016-09-01 09:26 Export PDF Favorites Scan
  • Application of low-dose contrast agent combined with physiological saline in SOMATOM Definition Flash CT angiography for head and neck

    ObjectiveTo explore the clinical value of low-dose contrast agnet in CT angiography (CTA) for head and neck by SOMATOM Definition Flash CT.MethodsSixty consecutive patients with head and neck vessel diseases examined by CTA in the head and neck were chosen from West China Hospital of Sichuan University from March to July 2015, and then were randomly divided into two groups (the experimental group: n=30, 30 mL contrast medium; the control group: n=30, 50 mL contrast medium). Imaging post processing techniques included curved plannar reconstruction, volume rendering, and maximal intensity projection. CT values of the different level of carotid arteries (aortic arch, carotid bifuracation, and M1 segment of middle cerebral artery) were measured. The artifact of the remaining contract in the jugular vein and overall quality of the image were observed by two senior doctors using double blind method.ResultsAll the patients in the two groups completed CTA for head and neck successfully. The image qualities of the two groups satisfid clinical diagnostic requirements, and there was no difference in the image qualities between the two groups (P>0.05). The evaluation of venous pollution in the experimental group was lighter than that in the control group (P<0.05). The CT values of aortic arch, carotid bifuracation, and M1 segment of middle cerebral artery in the experimental group [(341.3±89.5), (391.0±103.7), (305.0±62.0) HU] were slightly lower than those in the control group [(437.3±83.7), (532.5±113.3), (396.6±93.1) HU], which were statistically significant (P<0.05).ConclusionLow-dose contrast in CTA for head and neck by SOMATOM Definition Flash CT can satisfy the clinical diagnostic requirements, and reduce the dose of contrast agent and venous pollution, with a good clinical value.

    Release date:2018-08-20 02:24 Export PDF Favorites Scan
  • Value of Contrast-Enhanced Ultrasound in Differential Diagnosis of Preoperative Benign and Malignant Breast Mass: A Systematic Review

    ObjectiveTo systematically review the clinical value of the contrast-enhanced ultrasonic in the diagnosis of breast tumors. MethodsWe electronically and comprehensively searched the databases including The Cochrane Library (Issue 2, 2013), PubMed, CNKI, WanFang Data, Chaoxing medalink, VIP, and CBM for clinical research reports of diagnosing breast cancer with Contrast-enhance ultrasonic (all from foundation to May 2013). Two reviewers independently screened literature according to the inclusion and exclusion criteria, extracted data, and assessed the methodological quality of the included studies according to the QUADAS items. The Meta-DiSc software (version 1.4) was used to conduct pooling on sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio. Heterogeneity test was performed and the summary receiver operating characteristic (SROC) curve was drawn for area under the curve (AUC). ResultsA total of 19 studies involving 1 161 participants were included. The results of meta-analysis showed that, specificity, the pooled sensitivity, positive likelihood ratio, negative likelihood ratio and DOR were 0.79 (95%CI 0.75 to 0.82), 0.86 (95%CI 0.83 to 0.89), 3.92 (95%CI 2.77 to 6.56), 0.18 (95%CI 0.13 to 0.26), and 25.86 (95%CI 13.77 to 48.55), respectively. The AUC of the SROC curve was 0.917 0. ConclusionThe current evidence shows that contrast-enhanced ultrasonic has high sensitivity and specificity in the diagnosis of preoperative benign and malignant breast mass, which indicates that it could be used as a good method to diagnosing breast tumors.

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