Objective To investigate the value of the novel lymphatic contrast-enhanced ultrasound(LCEUS)and conventional venous contrast-enhanced ultrasound(VCEUS)in the differential diagnosis of benign and malignant cervical lymph nodes in patients with thyroid cancer. Methods Patients with suspected thyroid cancer underwent conventional ultrasound,VCEUS,and LCEUS examinations of cervical lymph nodes before biopsy.The diagnostic abilities of conventional ultrasound,VCEUS,and LCEUS were compared with pathological results as the golden standard. Results Forty-four patients with 52 lymph nodes were included in the final data.Thirty-eight metastatic lymph nodes were confirmed by pathological results,and 14 were benign.The diagnostic sensitivity,specificity,and accuracy were 97.37%,71.43%,and 90.38% for LCEUS,92.11%,35.71%,and 76.92% for VCEUS,and 94.74%,21.43%,and 75.00% for conventional ultrasound,respectively.The area under the curve of LCEUS analyzed by the receiver operating characteristic curve was greater than that of VCEUS(P=0.020)and conventional ultrasound(P<0.001). Conclusion LCEUS could significantly improve the differential diagnosis of cervical lymph node metastasis in the patients with thyroid cancer,providing a basis for precise clinical treatment.
Humans ; Thyroid Neoplasms/diagnostic imaging* ; Lymphatic Metastasis/diagnostic imaging* ; Diagnosis, Differential ; Female ; Male ; Middle Aged ; Ultrasonography ; Adult ; Lymph Nodes/pathology* ; Contrast Media ; Neck ; Aged ; Young Adult ; Adolescent ; Sensitivity and Specificity

In light of the increasing use of online learning platforms in medical education, there is a critical need to assess the current state of online learning environments. Despite the global emphasis on digital education, limited studies have systematically explored how medical students perceive the effectiveness and quality of these environments, particularly in Pakistan. This study aims to fill this gap by evaluating medical students’ experiences with their institution’s online learning environments and identifying key strengths and challenges that impact learning outcomes. A mixed-method, sequential exploratory design was used, starting with a quantitative assessment followed by qualitative inquiry. Data from 253 medical students were collected via a survey, and 30 focus group interviews were conducted to provide deeper insights into the challenges students face in navigating the online learning environment. The findings revealed critical areas in need of improvement, including digital infrastructure, student engagement, and the accessibility of online resources. Qualitative data highlighted the need for more interactive and student-centred approaches to online education. By focusing on the status of online learning in medical education, this research provides valuable insights for educators and policymakers aiming to enhance the quality of digital learning environments. The study contributes to ongoing efforts to develop more effective, engaging, and responsive online learning strategies for medical students in Pakistan.
Education, Distance ; Education, Medical, Undergraduate ; Perception

OBJECTIVES: Digital subtraction angiography (DSA) is the current gold standard for diagnosing spinal dural arteriovenous fistulas (SDAVF). However, DSA is invasive and associated with risks such as ionizing radiation and iodine contrast allergy. Contrast-enhanced magnetic resonance angiography (CE-MRA) with high temporal/high spatial resolution allows dynamic multiphase contrast-enhanced imaging with excellent detail. This study aims to evaluate the diagnostic value of spinal CE-MRA with high temporal/high spatial resolution for SDAVF. METHODS: Clinical data were retrospectively collected from patients who underwent both conventional spinal MRI and high temporal/high spatial resolution CE-MRA at Xiangya Hospital between January 1, 2021, and January 1, 2024, and who subsequently underwent DSA or surgery within 90 days. Two experienced radiologists independently reviewed all conventional MRI and CE-MRA images. The sensitivity and specificity of conventional MRI and CE-MRA for diagnosing SDAVF were calculated against the gold standard DSA findings. Kappa statistics were used to evaluate the consistency of MRI and CE-MRA compared to DSA. The diagnostic value was further assessed by calculating the area under curve (AUC) of the receiver operating characteristic (ROC). RESULTS: A total of 60 patients were included, of whom 47 were diagnosed with SDAVF and 13 were not. Conventional MRI had 3 false negatives and 1 false positive; CE-MRA had 2 false positives and 0 false negative. The sensitivity and specificity of conventional MRI were 93.62% and 92.31%, respectively. CE-MRA demonstrated 100% sensitivity and 84.62% specificity. The main cause of false positives was the misidentification of posterior spinal arteries as feeding arteries. CE-MRA clearly displayed most feeding arteries, and the accuracy of fistula localization was 74.47% (35/47). Kappa values for conventional MRI and CE-MRA were 0.814 and 0.896, respectively (both P<0.001), indicating good agreement, with CE-MRA outperforming conventional MRI. The AUCs for diagnosing SDAVF were 0.930 for conventional MRI and 0.923 for CE-MRA (both P<0.05). CONCLUSIONS Spinal CE-MRA with high temporal/high spatial resolution is a reliable, non-invasive imaging technique with high sensitivity for diagnosing SDAVF. It can clearly visualize feeding arteries and provides valuable preoperative diagnostic and localization information to support DSA or surgical planning.
Humans ; Central Nervous System Vascular Malformations/diagnosis* ; Male ; Female ; Retrospective Studies ; Middle Aged ; Magnetic Resonance Angiography/methods* ; Angiography, Digital Subtraction/methods* ; Aged ; Adult ; Sensitivity and Specificity ; Contrast Media ; Magnetic Resonance Imaging/methods*

Previous studies have proposed two cognitive mechanisms responsible for the Ebbinghaus illusion effect, i.e., contour interaction and size contrast. However, the neural underpinnings of these two mechanisms are largely unexplored. The present study introduced binocular depth to the Ebbinghaus illusion configuration and made the central target appear either in front of or behind the surrounding inducers in order to disturb size contrast instead of contour interaction. The results showed that the illusion effect, though persisted, was significantly reduced under the binocular depth conditions. Notably, the target with a larger perceived size reduced early alpha-band power (8-13 Hz, 0-100 ms after stimulus onset) at centroparietal sites irrespective of the relative depth of the target and the inducers, with the parietal alpha power negatively correlated with the illusion effect. Moreover, the target with a larger perceived size increased the occipito-parietal beta-band power (14-25 Hz, 200-300 ms after stimulus onset) under the no-depth condition, and the beta power was positively correlated with the illusion effect when the depth conditions were subtracted from the no-depth condition. The findings provided neurophysiological evidence in favor of the two cognitive mechanisms of the Ebbinghaus illusion by revealing that early alpha power is associated with low-level contour interaction and late beta power is linked to high-level size contrast, supporting the claim that neural oscillations at distinct frequency bands dynamically support different aspects of visual processing.
Humans ; Alpha Rhythm/physiology* ; Female ; Male ; Size Perception/physiology* ; Young Adult ; Adult ; Beta Rhythm/physiology* ; Photic Stimulation/methods* ; Illusions/physiology* ; Optical Illusions/physiology* ; Depth Perception/physiology*

BACKGROUND: Patients with mass-forming pancreatitis (MFP) or pancreatic ductal adenocarcinoma (PDAC) presented similar clinical symptoms, but required different treatment approaches and had different survival outcomes. This meta-analysis aimed to compare the diagnostic performance of contrast-enhanced ultrasound (CEUS) and contrast-enhanced computed tomography (CECT) in differentiating MFP from PDAC. METHODS: A literature search was performed in the PubMed, EMBASE (Ovid), Cochrane Library (CENTRAL), China National Knowledge Infrastructure (CNKI), Weipu (VIP), and WanFang databases to identify original studies published from inception to August 20, 2021. Studies reporting the diagnostic performances of CEUS and CECT for differentiating MFP from PDAC were included. The meta-analysis was performed with Stata 15.0 software. The outcomes included the pooled sensitivity, specificity, positive likelihood ratio (+LR), negative likelihood ratio (-LR), diagnostic odds ratio (DOR), and summary receiver operating characteristic (SROC) curves of CEUS and CECT. Meta-regression was conducted to investigate heterogeneity. Bayesian network meta-analysis was conducted to indirectly compare the overall diagnostic performance. RESULTS: Twenty-six studies with 2115 pancreatic masses were included. The pooled sensitivity and specificity of CEUS for MFP were 82% (95% confidence interval [CI], 73%-88%; I2  = 0.00%) and 95% (95% CI, 90%-97%; I2  = 63.44%), respectively; the overall +LR, -LR, and DOR values were 15.12 (95% CI, 7.61-30.01), 0.19 (95% CI, 0.13-0.29), and 78.91 (95% CI, 30.94-201.27), respectively; and the area under the SROC curve (AUC) was 0.90 (95% CI, 0.87-92). However, the overall sensitivity and specificity of CECT were 81% (95% CI, 75-85%; I2  = 66.37%) and 94% (95% CI, 90-96%; I2  = 74.87%); the overall +LR, -LR, and DOR values were 12.91 (95% CI, 7.86-21.20), 0.21 (95% CI, 0.16-0.27), and 62.53 (95% CI, 34.45-113.51), respectively; and, the SROC AUC was 0.92 (95% CI, 0.90-0.94). The overall diagnostic accuracy of CEUS was comparable to that of CECT for the differential diagnosis of MFP and PDAC (relative DOR 1.26, 95% CI [0.42-3.83], P  > 0.05). CONCLUSIONS CEUS and CECT have comparable diagnostic performance for differentiating MFP from PDAC, and should be considered as mutually complementary diagnostic tools for suspected focal pancreatic lesions.
Humans ; Contrast Media ; Bayes Theorem ; Tomography, X-Ray Computed/methods* ; Pancreatic Neoplasms/diagnostic imaging* ; Carcinoma, Pancreatic Ductal/diagnostic imaging* ; Sensitivity and Specificity ; Pancreatitis/diagnostic imaging* ; Ultrasonography/methods*

In this study, we explored the neural mechanism underlying impaired stereopsis and possible functional plasticity after strabismus surgery. We enrolled 18 stereo-deficient patients with intermittent exotropia before and after surgery, along with 18 healthy controls. Functional magnetic resonance imaging data were collected when participants viewed three-dimensional stimuli. Compared with controls, preoperative patients showed hypoactivation in higher-level dorsal (visual and parietal) areas and ventral visual areas. Pre- and postoperative activation did not significantly differ in patients overall; patients with improved stereopsis showed stronger postoperative activation than preoperative activation in the right V3A and left intraparietal sulcus. Worse stereopsis and fusional control were correlated with preoperative hypoactivation, suggesting that cortical deficits along the two streams might reflect impaired stereopsis in intermittent exotropia. The correlation between improved stereopsis and activation in the right V3A after surgery indicates that functional plasticity may underlie the improvement of stereopsis. Thus, additional postoperative strategies are needed to promote functional plasticity and enhance the recovery of stereopsis.
Humans ; Exotropia/surgery* ; Depth Perception/physiology* ; Strabismus/surgery* ; Oculomotor Muscles/surgery*

Objective: To compare the visual performance and patient-reported outcomes of three types of monofocal intraocular lenses (IOL) with different asphericities. Methods: This cross-sectional, comparative study comprised of 62 pseudophakic eyes divided into three groups corresponding to the IOL that they were previously implanted with (Tecnis ZCB00 negative aspheric IOL, EnVista MX60 neutral aspheric IOL and Akreos Adapt spheric IOL). Mean refractive spherical equivalent (MRSE), best-corrected far visual acuity (BCVA), spherical aberration (SA), contrast sensitivity (SC), halo and starburst, and responses to a qualitative questionnaire (NEI-RQL) were measured. Results: There was no significant difference in MRSE (P=0.74) and BCVA (P=0.52) among the three groups. There was a statistically significant difference (P=0.00) in mean internal (lens) SA, measured through a 5mm pupil, among Tecnis (-0.150 μm), EnVista (+0.022 μm) and Akreos Adapt (+0.094 μm). Compared to the Akreos Adapt, the Tecnis and EnVista groups had significantly better CS at 6 CPD and 12 CPD under mesopic testing without glare (P= 0.01) and at 6 CPD mesopic testing with glare (P=0.04). Halo scores were insignificant among the three groups. However, starburst scores were significantly worse in the Akreos Adapt IOL than the Tecnis and EnVista (P=0.01). There was no difference in questionnaire responses among the three groups. Conclusion The negative aspheric and neutral aspheric lenses showed significantly lower SA resulting in better CS in mesopic conditions and better starburst scores. MRSE, BCVA and subjective satisfaction were statistically similar regardless of the type of monofocal intraocular lens
Contrast Sensitivity

INTRODUCTION: This study aimed to evaluate the potential of non-contrast-enhanced magnetic resonance (MR) imaging as an imaging surveillance tool for detection of hepatocellular carcinoma (HCC) in at-risk patients and to compare the performance of non-contrast MR imaging with ultrasonography (US) as a screening modality for the same. METHODS: In this retrospective study, patients diagnosed with HCC between 1 January 2010 and 31 December 2015 were selected from our institution's cancer registry. Patients who underwent MR imaging and had US performed within three months of the MR imaging were included. For each MR imaging, two non-contrast MR imaging sequences - T2-weighted fat-saturated (T2-W FS) sequence and diffusion-weighted imaging (DWI) - were reviewed for the presence of suspicious lesions. A non-contrast MR image was considered positive if the lesion was seen on both sequences. The performance of non-contrast MR imaging was compared to that of hepatobiliary US for the detection of HCC. RESULTS: A total of 73 patients with 108 HCCs were evaluated. Sensitivity of non-contrast MR imaging for the detection of HCC using T2-W FS and DWI was 93.2%, which was significantly higher than that of US, which was 79.5% (p = 0.02). In a subgroup of 55 patients with imaging features of liver cirrhosis, the sensitivity of non-contrast MR imaging was 90.9%, which was also significantly higher than that of US, which was 74.5% (p = 0.02). CONCLUSION Our pilot study showed that non-contrast MR imaging, using a combination of T2-W FS and DWI, is a potential alternative to US as a screening tool for surveillance of patients at risk for HCC.
Carcinoma, Hepatocellular/pathology* ; Contrast Media ; Diffusion Magnetic Resonance Imaging/methods* ; Gadolinium DTPA ; Humans ; Liver Neoplasms/pathology* ; Magnetic Resonance Imaging/methods* ; Pilot Projects ; Retrospective Studies ; Sensitivity and Specificity

Contrast-enhanced ultrasound (CEUS) is a new form of ultrasound (US) that can dynamically display microvessels in a highly sensitive manner. The purpose of this study was to investigate the efficacy of CEUS for characterizing testicular lesions in comparison with conventional US. Forty-seven patients with testicular lesions were enrolled. The histopathology results revealed that 31 cases were neoplastic (11 cases of seminomas, 8 nonseminomatous germ cell tumors, 8 lymphomas, 2 Leydig cell tumors, and 2 nonspecific tumors), and 16 cases were nonneoplastic (8 cases of infarctions, 3 epidermoid cysts, and 5 inflammation). The indicators of shallow lobulated morphology and cystic-solid echogenicity on conventional US were suggestive of germ cell tumors. More indicators on CEUS were found to be useful for characterizing testicular lesions. All the neoplastic lesions showed hyperenhancement on CEUS. Moreover, germ cell tumors presented with heterogeneous enhancement (73.7%, 14/19), a twisted blood vessel pattern, rapid wash-in and wash-out, and peripheral rim hyperenhancement signs. Lymphoma was characterized by nonbranching linear vessel patterns (87.5%, 7/8), rapid wash-in and slow wash-out. In nonneoplastic lesions, infarction and epidermoid cysts showed no enhancement, and abscesses were observed with marginal irregular enhancement. The sensitivity, specificity, and accuracy of CEUS for differentiating between neoplastic and nonneoplastic lesions were 100%, 93.8%, and 97.9%, respectively, and these values were higher than those for conventional US (90.3%, 62.5%, and 80.9%, respectively). CEUS can sensitively reflect the microvascular perfusion in testicular lesions and offers high accuracy for characterizing them.
Contrast Media ; Diagnosis, Differential ; Epidermal Cyst ; Humans ; Lymphoma ; Male ; Neoplasms, Germ Cell and Embryonal/diagnostic imaging* ; Sensitivity and Specificity ; Testicular Neoplasms/diagnostic imaging* ; Ultrasonography/methods*

BACKGROUND: Pre-operative non-invasive histological evaluation of hepatocellular carcinoma (HCC) remains a challenge. Tumor perfusion is significantly associated with the development and aggressiveness of HCC. The purpose of the study was to evaluate the clinical value of quantitative liver perfusion parameters and corresponding histogram parameters derived from traditional triphasic enhanced computed tomography (CT) scans in predicting histological grade of HCC. METHODS: Totally, 52 patients with HCC were enrolled in this retrospective study and underwent triple-phase enhanced CT imaging. The blood perfusion parameters were derived from triple-phase CT scans. The relationship of liver perfusion parameters and corresponding histogram parameters with the histological grade of HCC was analyzed. Receiver operating characteristic (ROC) curve analysis was used to determine the optimal ability of the parameters to predict the tumor histological grade. RESULTS: The variance of arterial enhancement fraction (AEF) was significantly higher in HCCs without poorly differentiated components (NP-HCCs) than in HCCs with poorly differentiated components (P-HCCs). The difference in hepatic blood flow (HF) between total tumor and total liver flow (ΔHF = HFtumor - HFliver) and relative flow (rHF = ΔHF/HFliver) were significantly higher in NP-HCCs than in P-HCCs. The difference in portal vein blood supply perfusion (PVP) between tumor and liver tissue (ΔPVP) and the ΔPVP/liver PVP ratio (rPVP) were significantly higher in patients with NP-HCCs than in patients with P-HCCs. The area under ROC (AUC) of ΔPVP and rPVP were both 0.697 with a high sensitivity of 84.2% and specificity of only 56.2%. The ΔHF and rHF had a higher specificity of 87.5% with an AUC of 0.681 and 0.673, respectively. The combination of rHF and rPVP showed the highest AUC of 0.732 with a sensitivity of 57.9% and specificity of 93.8%. The combined parameter of ΔHF and rPVP, rHF and rPVP had the highest positive predictive value of 0.903, and that of rPVP and ΔPVP had the highest negative predictive value of 0.781. CONCLUSION Liver perfusion parameters and corresponding histogram parameters (including ΔHF, rHF, ΔPVP, rPVP, and AEFvariance) in patients with HCC derived from traditional triphasic CT scans may be helpful to non-invasively and pre-operatively predict the degree of the differentiation of HCC.
Carcinoma, Hepatocellular/diagnostic imaging* ; Contrast Media ; Humans ; Liver Neoplasms/diagnostic imaging* ; Perfusion ; Retrospective Studies ; Sensitivity and Specificity ; Tomography, X-Ray Computed