[Evaluation of the method to predict the difficulty of the test questions in a national dental board examination].

PURPOSE: To explore a possible method of improving prediction by analyzing the effect and influencial factors of difficulty prediction of a national board dental examinations. METHODS: The correlation between the predicted value and the measured value, and related influential factors were analyzed with SPSS 16.0 software package. RESULTS: The correlation between the predicted difficulty and the tested difficulty increased after the improvement of the method (P＜0.05). The correlation was mainly reflected in the median score group of candidates. CONCLUSIONS: Improving the method of difficulty prediction can increase the prediction effect, and it is helpful to improve the forecasting ability of the test paper and to evaluate the candidates accurately.

Flat detector C-arm CT-guidance system in performing percutaneous transthoracic needle biopsy of small (≤3 cm) pulmonary lesions.

BACKGROUND: Nowadays, flat detector (FD) equipped angiographic C-arm computed tomography (CACT) systems can be used to acquire CT-like cross-sectional images directly within the interventional suite. The CACT systems offer real time visualization of transthoracic needle biopsy (TNB) procedure and more flexibility in the orientation of the detector system around the patient compared to traditional CT systems. PURPOSE: To evaluate the value of a flat detector C-arm CT-guidance system in performing percutaneous transthoracic needle biopsy (PTNB) for small (≤3 cm) pulmonary lesions in clinical practice. MATERIAL AND METHODS: A total of 60 patients with solid lung lesions were retrospectively enrolled to undergo PTNB procedures. The mean diameter of lesions was 2.3 ± 0.6 cm (range, 0.6-3 cm). The needle path was carefully planned and calculated on the C-arm CT system, which acquired three-dimensional CT-like cross-sectional images. The PTNB procedures were performed under needle guidance with fluoroscopic feedbacks. RESULTS: Histopathologic tissue was successfully obtained from 59 patients with a puncture success rate of 98.3% (59/60). The diagnostic accuracy rate was found to be 91.5% (54/59). There were only two cases of pneumothorax (3.3%) requiring therapy. The rates of pneumothorax and hemoptysis were low (15.0% [9/60] and 8.3% [5/60], respectively). The overall procedural time was in the range of 12-18 min, resulting in a mean exposure dose of 224.4 ± 4.8 mGy. CONCLUSION: Our study shows that C-arm CT-based needle guidance enables reliable and efficient needle positioning and progression by providing real-time intraoperative guidance for small (≤3 cm) pulmonary lesions in clinical practice.