Contrast-enhanced US-assisted Percutaneous Nephrostomy: A Technique to Increase Success Rate for Patients with Nondilated Renal Collecting System.

Purpose To perform a single-center study of contrast material-enhanced ultrasonography (US)-assisted percutaneous nephrostomy (PCN) for patients with nondilated renal collecting system. Materials and Methods An international review board approved this retrospective study with waiver of informed consent for participation, and the study was approved by the Ethical Committee. From November 2011 to September 2015, 47 patients (mean age, 51.9 years ± 16.2 [standard deviation]; range, 18-80 years) with clinical necessity of urinary drainage, urinary diversion, or provision of access to the collecting system and with nondilated renal collecting system who underwent contrast-enhanced US-assisted PCN for 48 kidneys were included. US contrast agent was injected through the puncture needle and the drainage catheter to confirm successful PCN. The technical success rate and complications were evaluated. Relative frequencies with 95% confidence intervals (CIs) were calculated. Results The technical success rate was 100% (47 of 47, 95% CI: 93.8%, 100%) per patient and 100% (48 of 48, 95% CI: 94.0%, 100%) per kidney. For each kidney, the mean number of needle passes was 1.4 ± 0.5 (range, 1-3). The mean duration of the complete procedure was 18.9 minutes ± 4.8 (range, 8-30 minutes). The mean dose of contrast agent was 12.9 mL ± 3.2 (range, 8-25 mL). No major complications were observed. After a follow-up of 1-30 days (mean, 18.4 days ± 10.3), only four patients (four of 47, 8.5%, 95% CI: 2.37%, 20.4%) had minor complications, including one perirenal hematoma seen at US 9 days after the procedure and three patients with transient macroscopic hematuria that lasted 1-2 days. Conclusion Contrast-enhanced US-assisted PCN in patients with nondilated renal collecting system is valuable with high technical success rate. © RSNA, 2017.

Liver cancer: increased microwave delivery to ablation zone with cooled-shaft antenna--experimental and clinical studies.

PURPOSE: To prospectively investigate whether the ablation zone induced with microwaves could be increased by delivering greater energy with a cooled-shaft antenna. MATERIALS AND METHODS: All studies were animal care and ethics committee approved. Written informed consent was obtained from all patients. Microwave ablation was performed by using a cooled-shaft antenna in 48 ex vivo and 12 in vivo experiments with porcine livers. The coagulation diameters achieved in different microwave ablation parameter groups (60-90 W for 5-25 minutes) were compared. Ninety patients (78 men, 12 women; mean age, 53 years; age range, 20-82 years) with 133 0.8-8.0-cm (mean, 2.7 cm +/- 1.5 [standard deviation]) primary or metastatic liver cancers were treated with the same microwave ablation technique. Complete ablation (CA) and local tumor progression (LTP) rates were determined. Generalized estimating equations were used to compare differences in tumor size, ablation zone diameter, and CA and LTP rates between different patient subgroups. RESULTS: In the ex vivo livers, in vivo livers, and liver cancers, one application of microwave energy with 80 W for 25 minutes produced mean coagulation diameters of 5.6 x 7.4 cm, 3.5 x 5.9 cm, and 3.6 x 5.0 cm, respectively. Skin burn was not observed. CA rates in small (