Constructing an experiential education model in undergraduate radiology education by the utilization of the picture archiving and communication system (PACS).

BACKGROUND: Medical education in China is in a transitional period, from passive learning models to experiential education. We modified an experiential education method for radiology education. The aim of this study is to evaluate the effect of this method on undergraduate radiology education. METHOD: With the help of the picture archiving and communication system (PACS) and RadiAnt DICOM Viewer, we modified an experiential education method that simulates similar working conditions for undergraduate medical students to formulate radiology diagnosis similar to clinical radiologists. A total of 101 students were allocated into either the experiential education group or the control group. The final examination scores and a 5-point Likert scale self-assessment questionnaire of radiologic skills were collected from all the students as an objective assessment and a subjective assessment respectively. A questionnaire was also used to assess the satisfaction with the experiential model in the experiential education group. Mann-Whitney U test was used to compare the ranked data, and t-tests were used to compare the numeric data. RESULTS: The experiential education group demonstrated significantly higher scores (7.4 ± 1.3) compared to the control group (6.7 ± 1.5, p < 0.05) in the question type "description and diagnosis". The self-assessment questionnaire indicated that the experiential education was related to increased familiarity with the diagnosis thinking principle and the sequences and reconstruction methods of computer tomography (CT) imaging, which also strengthen participants' self-confidence to perform future clinical work (p < 0.05). The self-assessment questionnaire in the experiential education group showed that the majority of students were satisfied with the organization (82.5%), interactivity (85%) and quality (85%) of the learning activity. Most students found this model of learning to be helpful for studying radiology (85%) and for understanding anatomy (90%). CONCLUSION: Compared with the traditional radiology education approach, the experiential education method showed greater efficacy in improving students' analysis and diagnostic skills and their self-confidence.

Percutaneous thermal ablation for the treatment of colorectal liver metastases and hepatocellular carcinoma: a comparison of local therapeutic efficacy.

AIM: This study aimed to compare the local therapeutic efficacy of percutaneous thermal ablation for colorectal liver metastases (CRLM) and hepatocellular carcinoma (HCC). METHODS: One hundred sixty-one CRLM nodules in 101 patients and 122 HCC nodules in 97 patients were treated with thermal ablation. Complications and local efficacy were retrospectively compared. RESULTS: Major complications were observed in two (2.0%) patients in the CRLM group and one (1.0%) in the HCC group (p = 1.000). The complete ablation (CA) rate of lesions ≤ 3 cm was lower in the CRLM group than in the HCC group (p = 0.018). After a mean follow-up period of 21.1 ± 20.7 months in the CRLM group and 22.1 ± 17.6 months in the HCC group, the local tumour progression (LTP) rate of lesions > 3 cm was higher in the CRLM group than in the HCC group (p = 0.036). The multivariate analysis revealed that only safety margin (≤ 0.5 cm/> 0.5 cm) was a significant predictor of LTP in both CRLM and HCC. CONCLUSIONS: To achieve better local tumour control, thermal ablation should be more aggressive for CRLM than for HCC, especially for large tumours in clinical.

Cholangiocarcinoma: spectrum of appearances on Gd-EOB-DTPA-enhanced MR imaging and the effect of biliary function on signal intensity.

BACKGROUND: To describe the Gd-EOB-DTPA-enhanced MRI appearances of cholangiocarcinoma, and evaluate the relative signal intensities (RSIs) changes of major abdominal organs, and investigate the effect of total bilirubin (TB) levels on the RSI. METHODS: 25 patients with pathologically-proven cholangiocarcinoma underwent Gd-EOB-DTPA-enhanced MRI. The visualization of the biliary system during biliary phase (BP) was observed. RSIs of the abdominal aorta (A), portal vein (V), liver (L), and spleen (S) were measured. RESULTS: On hepatocellular phase (HP), exophytic tumors (n =10) and infiltrative tumors (n =10) were hypointense, polypoid tumors (n = 2) were hypointense, and combined type tumors (n = 3) had mixed appearances. While patients with normal TB levels (≤22 µmol/L, n = 12) had clear visualization of the biliary tree during BP, those with elevated TB levels (>22 µmol/L, n = 13) had obscured or no visualization. In addition, patients with normal TB levels had higher RSIA, RSIV and RSIS than those with elevated TB levels on all dynamic phases (P <0.001), and lower RSIA, RSIV and RSIS on HP and BP (P <0.001). Patients with normal TB levels had higher RSIL than those with elevated TB levels on all phases (P <0.001). CONCLUSIONS: RSIs of major abdominal organs reflected underlying biliary function. Cholangiocarcinoma patients with elevated TB levels had delayed excretion of Gd-EOB-DTPA compared with patients with normal TB levels.

Comparison of contrast-enhanced ultrasound and contrast-enhanced computed tomography in evaluating the treatment response to transcatheter arterial chemoembolization of hepatocellular carcinoma using modified RECIST.

PURPOSE: We aimed to compare contrast-enhanced ultrasound (CEUS) with contrast-enhanced computed tomography (CECT) for evaluating the treatment response to transcatheter arterial chemoembolization (TACE) of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Treatment responses of 130 patients who underwent TACE were evaluated by CEUS and CECT. We initially compared the abilities of CEUS and CECT to detect residual tumour, which were confirmed by histology or angiography. Then, we compared the tumour response to TACE assessed by CEUS and CECT, according to Modified Response Evaluation Criteria in Solid Tumours (mRECIST). RESULTS: The sensitivity and accuracy of detecting residual tumour by CEUS vs. CECT were 95.9 % vs. 76.2 % (p < 0.001) and 96.2 % vs. 77.7 % (p < 0.001), respectively. For target lesions, 13 patients were observed as complete response (CR) by CEUS, compared to 36 by CECT (p < 0.001). For nontarget lesions, 12 patients were observed as CR by CEUS, compared to 22 by CECT (p = 0.006). For overall response, eight patients were observed as CR by CEUS, compared to 31 by CECT (p < 0.001). CONCLUSION: The diagnostic performance of CEUS was superior to CECT for detecting residual tumour after TACE. In clinical, CEUS should be recommended as an optional procedure for assessing the tumour response to TACE. KEY POINTS: • The mRECIST are widely applied for evaluating the response of HCC. • Imaging method has been applied to assess the therapeutic response to TACE. • The diagnostic performance of CEUS was superior to CECT for residual tumours. • CEUS can be a valuable method for assessing tumour response to TACE.

Functional magnetic resonance cholangiography enhanced with Gd-EOB-DTPA: effect of liver function on biliary system visualization.

PURPOSE: To evaluate effect of liver function on biliary system visualization using gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance cholangiography (CE-MRC). MATERIALS AND METHODS: In all, 39 patients were divided into three groups according to their Child-Pugh classification: group A, Child-Pugh class A (23); group B, class B (11); and group C, class C (5). They underwent Gd-EOB-DTPA CE-MRC. Biliary system visualization was qualitatively rated on a 5-point scale. Relative signal intensity (RSI) of common bile duct (CBD) and liver was quantitatively measured. Laboratory findings and the Model of Endstage Liver Disease (MELD) score were recorded. RESULTS: Visualization ratings of CBD, left hepatic duct, right hepatic duct, segmental branches of intrahepatic ducts, cystic duct, and gallbladder of group A were: 3.61 ± 0.58, 2.87 ± 0.97, 2.96 ± 0.77, 1.17 ± 0.58, 3.04 ± 0.83, 3.00 ± 0.95, respectively; group B: 2.00 ± 0.61, 1.09 ± 0.64, 0.91 ± 0.54, 0.27 ± 0.13, 1.36 ± 0.62, 1.45 ± 0.54, respectively; group C: 1.40 ± 0.73, 1.00 ± 0.51, 1.00 ± 0.51, 0.00 ± 0.00, 0.60 ± 0.39, 0.60 ± 0.39, respectively. RSI of CBD of groups A to C were 17.12 ± 0.41, 3.95 ± 0.63, 3.33 ± 0.30, respectively. RSI of liver of groups A to C were 6.73 ± 0.72, 2.53 ± 1.02, 2.05 ± 0.11, respectively. CE-MRC images of group A were significantly better than those of group B and C in terms of both visualization ratings and RSI of CBD. CBD RSI positively correlated with liver RSI (r = 0.99, P < 0.001). The total serum bilirubin level and MELD score were significant predictors of RSI of CBD. CONCLUSION: Different liver function according to Child-Pugh classification significantly affects biliary system visualization of Gd-EOB-DTPA CE-MRC.

Prediction of Microvascular Invasion in Hepatocellular Carcinoma: Preoperative Gd-EOB-DTPA-Dynamic Enhanced MRI and Histopathological Correlation.

Objective: To investigate the imaging features observed in preoperative Gd-EOB-DTPA-dynamic enhanced MRI and correlated with the presence of microvascular invasion (MVI) in hepatocellular carcinoma (HCC) patients. Methods: 66 HCCs in 60 patients with preoperative Gd-EOB-DTPA-dynamic enhanced MRI were retrospectively analyzed. Features including tumor size, signal homogeneity, tumor capsule, tumor margin, peritumor enhancement during mid-arterial phase, peritumor hypointensity during hepatobiliary phase, signal intensity ratio on DWI and apparent diffusion coefficients (ADC), T1 relaxation times, and the reduction rate between pre- and postcontrast enhancement images were assessed. Correlation between these features and histopathological presence of MVI was analyzed to establish a prediction model. Results: Histopathology confirmed that MVI were observed in 17 of 66 HCCs. Univariate analysis showed tumor size (p = 0.003), margin (p = 0.013), peritumor enhancement (p = 0.001), and hypointensity during hepatobiliary phase (p = 0.004) were associated with MVI. A multiple logistic regression model was established, which showed tumor size, margin, and peritumor enhancement were combined predictors for the presence of MVI (α = 0.1). R2 of this prediction model was 0.353, and the sensitivity and specificity were 52.9% and 93.0%, respectively. Conclusion: Large tumor size, irregular tumor margin, and peritumor enhancement in preoperative Gd-EOB-DTPA-dynamic enhanced MRI can predict the presence of MVI in HCC.

Small hepatocellular carcinoma with peripheral enhancement: pathological correlation with dual phase images by helical CT.

BACKGROUND: The peripheral enhancement of small hepatocellular carcinoma (SHCC) is a rare appearance in dual phase images by helical computed tomography (CT). This study discusses this phenomenon and its correlative histopathology. METHODS: The helical CT dual phase appearance of peripheral enhancement in SHCC was analyzed in 21 cases (22 lesions). All lesions were confirmed as SHCC by histopathological examination. RESULTS: In these 22 lesions, enhanced peripheral ring in 20 lesions was incomplete, the thickness of enhanced peripheral ring varied and mural node could be found in hepatic arterial phase; only 2 lesions had complete peripheral ring enhancement and ring of uniform thickness in hepatic arterial phase. The enhancement of some peripheral rings and mural nodes dropped to very low density in portal venous phase. The tumour cells were grade I in 3 lesions, II in 16, III in 2 and IV in 1. The vascular supply was more abundant at the border than in the centre of 15 lesions and the vascular supply was deficient in both centre and border of the remaining 7 lesions. In 3 lesions, the pseudocapsule showed in the border of the lesion. In 12 lesions, flecks of necrosis were found in the border and/or centre of the lesion. CONCLUSIONS: The characteristic peripheral enhancement in helical CT dual phase images of small hepatocellular carcinoma correlates with different vascular supplies, fibrous capsule and necrosis of the lesion.

[Evaluation of microvessel density and vascular endothelial growth factor in colorectal carcinoma with 64-multidetector-row CT perfusion imaging].

OBJECTIVE: To evaluate the correlation of 64-multidetector-row CT (64MDCT) perfusion imaging with microvessel density(MVD) and vascular endothelial growth factor(VEGF) in colorectal carcinoma. METHODS: 64MDCT perfusion imaging was performed in 33 patients with pathologically verified colorectal carcinoma. Time-density curves (TDC) were created from the region of interest (ROI) drawn over the tumor, target artery and vein by 64MDCT with perfusion functional software. The individual perfusion maps generated were for blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability-surface area product (PS). MVD and VEGF expression of surgical specimens were examined by immunohistochemical staining with anti-CD34, anti-VEGF monoclonal antibody. MVD and VEGF were compared among the different types of TDC in colorectal carcinoma. The correlation of CT perfusion parameters with MVD and VEGF was also examined. RESULTS: TDC of colorectal carcinoma was divided into five types according to their shapes. MVD in the colorectal carcinoma was 22.61+/-9.01. VEGF staining was found in 25 of 29 tumors (86.2%). The score of VEGF expression was 4.15+/-1.09. No significant differences of MVD and VEGF expression among TDC types were found (F=2.59, 1.11, P>0.05). There were also no correlations of MVD and VEGF expression with any dynamic CT parameters (P>0.05). CONCLUSION: 64MDCT perfusion imaging, MVD and VEGF may reflect angiogenic activity, but no significant correlations are found among them.