Photon-counting CT: technical features and clinical impact on abdominal imaging.

Photon-counting CT has a completely different detector mechanism than conventional energy-integrating CT. In the photon-counting detector, X-rays are directly converted into electrons and received as electrical signals. Photon-counting CT provides virtual monochromatic images with a high contrast-to-noise ratio for abdominal CT imaging and may improve the ability to visualize small or low-contrast lesions. In addition, photon-counting CT may offer the possibility of reducing radiation dose. This review provides an overview of the actual clinical operation of photon-counting CT and its diagnostic utility in abdominal imaging. We also describe the clinical implications of photon-counting CT including imaging of hepatocellular carcinoma, liver metastases, hepatic steatosis, pancreatic cancer, intraductal mucinous neoplasm of the pancreas, and thrombus.

Visualization of small visceral arteries on abdominal CT angiography using ultra-high-resolution CT scanner.

PURPOSE: To evaluate the image quality and ability to delineate the small visceral arteries of high-resolution (HR) abdominal CT angiography (CTA) using an ultra-high-resolution computed tomography (UHR CT) scanner. MATERIALS AND METHODS: Thirty-seven patients were enrolled who underwent abdominal CTA using a UHR CT scanner. The images were reconstructed with a matrix of 1024 × 1024 and 0.25 mm thickness for HR CTA and with a matrix of 512 × 512 and 0.5 mm thickness for normal resolution (NR) CTA. Maximum CT value, image quality, and delineation of the small arteries were compared between HR CTA and NR CTA. RESULTS: HR CTA showed significantly higher maximum CT value, higher image quality, and better delineation of the small arteries than did NR CTA (P < .005). CONCLUSION: HR CTA using a UHR CT scanner showed higher image quality than NR CTA and enhanced the delineation of visceral arteries.

[Surgical Outcomes of Laparoscopic Repeat Hepatectomy at Our Institution].

Laparoscopic hepatectomy has gained popularity owing to its merits, such as low invasiveness and reduced bleeding. However, the efficacy of laparoscopic repeat hepatectomy(LRH)has not been confirmed. The aim of this study was to evaluate the feasibility and efficacy of LRH compared to that of open repeat hepatectomy(ORH). We performed 60 repeat hepatectomies from January 2011 to March 2019, of which 19 were LRH(Lap group)and 41 were ORH(Open group). This study retrospectively compared the patient characteristics and short-term outcomes of repeat hepatectomy between the Lap and Open groups. There were no significant differences in patient characteristics, except for the type of approach in the previous hepatectomy(p<0.01). The Lap group had lesser blood loss(median: 150 mL vs 355 mL, p<0.01)and shorter postoperative hospital stays(median: 8 days vs 11 days, p<0.01). There were no differences in operation time or severe postoperative complications. LRH is feasible and useful, providing good short-term outcomes.