Aaron Bos

The Emprint™ Ablation System with Thermosphere™ Technology: One of the Newer Next-Generation Microwave Ablation Technologies

Microwave ablation is a recent development in the field of tumor ablation that uses electromagnetic waves to establish a microwave near-field with direct tissue heating. Some of the limitations of the earlier generation devices had been unpredictable size and shape of the ablation zones with changes in the surrounding tissue environment as well as differences across various different tissue types. The Emprint Ablation System with Thermosphere Technology (Covidien, Boulder, CO) is the most recent generation ablation system that attempts to produce predictable large spherical zones of ablation despite varying tissue environments across different tissue types such as liver, lung, and bone to name a few. This article will discuss these recent device developments as well as review some basic microwave characteristics.

Strut Penetration: Local Complications, Breakthrough Pulmonary Embolism, and Retrieval Failure in Patients with Celect Vena Cava Filters

PURPOSE To investigate strut penetration in patients with Celect filters, specifically local complications and association with breakthrough pulmonary embolism (PE) or retrieval failure. MATERIALS AND METHODS A retrospective single-center study was conducted to evaluate patients who received Celect filters between January 2007 and May 2013. A total of 595 filters were placed during the study period. Primary indications included thromboembolic disease (93%) and primary surgical prophylaxis (7%). Complications and retrieval data were assessed by computed tomography (CT) and electronic medical records. RESULTS A total of 193 patients underwent follow-up abdominal CT at a mean follow-up interval of 176.2 days (range, 0-1,739 d). The rate of strut penetration more than 3 mm outside the caval wall was 28.5% (n = 55). One patient had CT evidence of clinically major strut penetration (1.8%) with strut compression of the right ureter causing hydronephrosis. Indwelling filter time longer than 100 days was associated with strut penetration (P < .001). Age, sex, and history of thromboembolic disease were not associated with strut penetration (P = .51, P = .81, and P = .89). Sixty-three patients presented for follow-up CT pulmonary angiography at a mean of 128.1 days (range, 1-895 d). The rate of breakthrough PE was 12.7%. The overall retrieval success rate was 96.7% (n = 150). Strut penetration was not associated with breakthrough PE or retrieval failure (P = .49 and P = .22). CONCLUSIONS Although strut penetration is a common complication with Celect filters, there is no association with breakthrough PE or retrieval failure. CT evidence of local complications associated with strut penetration is rare.

Indwelling and Retrieval Complications of Denali and Celect Infrarenal Vena Cava Filters

PURPOSE To compare indwelling and retrieval complications of Denali and Celect filters placed in the infrarenal inferior vena cava (IVC). MATERIALS AND METHODS A retrospective study was conducted over 2 years at a single institution in which 171 Denali and 162 Celect filters were placed in 333 patients with a mean age of 62.3 years ± 15.7 (161 men; 48.3%). Filter indications included venous thromboembolic disease (n = 320; 96.1%) and surgical prophylaxis (n = 13; 3.9%). A jugular approach was used to place 303 filters (91.0%). Computed tomography (CT) follow-up, complications, and retrieval data were obtained. RESULTS Follow-up CT imaging was performed on 58 filters from each group with lower incidences of caval strut penetration (one vs 12) and filter tilt (one vs 15) in the Denali filter group (P = .002 and P < .001, respectively). There was no difference in incidences of breakthrough pulmonary embolism (P = .68). Retrieval attempts were performed on 43 Denali and 53 Celect filters with mean indwelling times at retrieval of 128.2 and 144.1 days, respectively (P = .40). Mean fluoroscopy time at retrieval was lower in the Denali group (3.1 min vs 6.0 min; P = .01). There were fewer cases of complex retrieval in the Denali group (n = 2 vs 10; P = .06). Tilt, fluoroscopy time, and air kerma were associated with complex retrieval (P = .04, P < .001, and P < .001, respectively). There was one Denali filter deployment complication that led to retrieval failure. CONCLUSIONS This study suggests that Denali filters are associated with lower incidences of strut penetration and filter tilt as well as shorter fluoroscopy time at retrieval compared with Celect filters when placed in the infrarenal IVC.

Core Lung Biopsy for Biomarker Analysis: Is There Increased Risk Compared With Conventional Biopsy?

Purpose: The aim of the study was to compare the rate of pneumothorax and chest tube placement in patients undergoing conventional lung biopsy with those undergoing core lung biopsy for biomarker analysis. Materials and Methods: Twenty-three patients had biopsies performed for biomarker analysis (5 male, 18 female patients, mean age 67 y), and 173 patients underwent standard diagnostic lung biopsy (86 male, 87 female patients, mean age 68 y). All biopsies were performed under computed tomography guidance using the coaxial technique (19 G introducer needle and 20 G core biopsy needle). The number of core samples was noted for each case, and all complications were recorded in accordance with Society of Interventional Radiology guidelines. Results: In the biomarker analysis group, a mean of 5.1 core samples (range, 1 to 10) was obtained. In the conventional biopsy group, a mean of 2.9 core samples (range, 1 to 6) was obtained. The pneumothorax rate was 37.6% in the conventional biopsy group and 30.4% in the biomarker analysis group (P=0.505). The rate of chest tube placement was 16.8% in the conventional biopsy group and 8.7% in the biomarker analysis group (P=0.319). Lesion size was found to be an independent predictor of pneumothorax (P=0.031), whereas biopsy tract length was found to be an independent predictor of both pneumothorax (P<0.001) and chest tube placement (P=0.005) upon multivariate analysis. Conclusions: There is no statistically significant difference in the incidence of pneumothorax or chest tube placement between patients undergoing standard diagnostic lung biopsy and those requiring increased core samples for biomarker analysis.