Application and Evaluation of a 64-Slice CT Three-Dimensional Fusion Technique in the Determination of the Effective Ablation Margin after Radiofrequency Ablation of Hepatocellular Carcinoma.

Due to the low accuracy of traditional three-dimensional fusion technology in radiofrequency ablation of hepatocellular carcinoma, this paper studies the advantages of three-dimensional CT fusion technology over traditional two-dimensional imaging technology in preoperative visualization and radiofrequency ablation path selection of hepatocellular carcinoma. To study the prognostic differences of hepatocellular carcinoma patients with different ablation margins (AM) in the three groups, so as to explore the best AM value, so as to minimize the liver injury caused by radiofrequency ablation. The selected patients underwent CT plain scan and three-phase enhancement at 1, 3, 6, and 12 months after operation and were rechecked every 6 months. For recurrent patients, CT was rechecked every three months. The images were obtained by GE 64-slice spiral CT. The thickness of the reconstruction layer is 1 mm, and the interval is 1 mm. The reconstructed image is imported into 3D fusion software. The three-dimensional images of tumor focus, hepatic artery, portal vein, and hepatic vein were reconstructed by two experienced doctors by superimposing the saved tumor images, merging the vascular images into the display, and measuring the ablation boundary (AM value). The results showed that the recurrence rate in group A was higher than that in group B (P = 0.041), and there was no significant difference between group B and group C (P = 1.000). Compared with traditional two-dimensional imaging, three-dimensional CT fusion technology can display the anatomical structure and three-dimensional spatial relationship of tumors and blood vessels and select the best radiofrequency ablation path, so as to achieve accurate radiofrequency ablation.

Coronavirus Disease 2019: Initial Detection on Chest CT in a Retrospective Multicenter Study of 103 Chinese Patients.

PURPOSE: To evaluate the performance of chest CT regarding the initial presentation of patients suspected of having coronavirus disease 2019 (COVID-19). MATERIALS AND METHODS: Data from 103 patients who were under investigation for COVID-19 based on inclusion criteria according to the World Health Organization Interim Guidance were retrospectively collected from January 21, 2020, to February 14, 2020. All patients underwent chest CT scanning and reverse-transcription polymerase chain reaction (RT-PCR) testing for COVID-19 at hospital presentation. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) (with 95% confidence intervals) were calculated to evaluate the performance of CT. Subgroup analyses were also performed based on the geographical distribution of these cases in the province of Henan, China. RESULTS: There were 88/103 (85%) patients with COVID-19 confirmed by RT-PCR testing. The overall sensitivity, specificity, PPV, and NPV were 93% (85%, 97%), 53% (27%, 77%), 92% (83%, 96%), and 42% (18%, 70%), respectively. Similar results were shown in both geographic regions. The respective sensitivity, specificity, PPV, and NPV for chest CT in the districts of Xinyang and Zhumadian (n = 56) were 92% (80%, 97%), 63% (26%, 90%), 93% (81%, 98%), and 56% (23%, 85%), while these indicators in the district of Anyang (n = 47) were 95% (81%, 99%), 43% (12%, 80%), 90% (76%, 97%), and 60% (17%-93%). There were no significant differences in the prevalence of positive examinations in the two geographic subgroups for CT (P = .423) or RT-PCR (P = .931). CONCLUSION: Although initial chest CT obtained at hospital presentation showed high sensitivity in patients under investigation for COVID-19 in the two geographic regions in Henan Province, the NPV was only modest, suggesting a low value of CT as a screening tool.© RSNA, 2020.