Nephrectomy is the gold standard for the treatment of renal cell carcinoma (RCC). However, some patients are not suitable candidates for nephrectomy because of high surgical risk, reduced renal function, or the presence of multiple renal tumors. Percutaneous image-guided thermal ablation, including cryoablation and radiofrequency ablation, is a minimally invasive and highly effective treatment and can be used to treat RCC in patients who are not good candidates for surgery. This article will review percutaneous image-guided thermal ablation for RCC, covering treatment indications, ablation modalities and techniques, oncologic outcomes, and possible complications. In addition, the characteristics of each ablation modality and its comparison with nephrectomy are also presented.
This review summarizes the current findings on radiofrequency ablation (RFA) for stage I non-small cell lung cancer (NSCLC) from relevant literature published in the last decade. While most earlier studies included small populations and had short follow-up periods, more robust data have become available owing to prospective or large cohort studies. The reported overall survival rates after RFA for stage I NSCLC were 83-96%, 40-74%, and 23-61% at 1, 3, and 5 years, respectively, in recent studies. Furthermore, many comparative studies on the outcomes of RFA and stereotactic body radiotherapy have been performed. Most of these studies report no significant difference in survival outcomes between the therapies. Currently, major guidelines define RFA as a reasonable alternative treatment for stage I NSCLC in non-surgical candidates.
Percutaneous radiofrequency ablation (RFA) has been accepted as a minimally invasive therapeutic treatment for liver malignancies. Although RFA is usually applied for the treatment of small liver tumors (<3 cm), several technical developments have expanded the use of RFA. RFA is now used for the treatment of large liver tumors, and the number of complications associated with this treatment has decreased. These refinements may ultimately lead to better long-term prognosis. Here, we review recent refinements of liver RFA and provide technical tips.
For interventional radiology (IR), understanding the precise dose distribution is crucial to reduce the risks of radiation dermatitis to patients and staff. Visualization of dose distribution is expected to support radiation safety efforts immensely. This report presents techniques for perceiving the dose distribution using virtual reality (VR) technology and for estimating the air dose distribution accurately using Monte Carlo simulation for VR dose visualization. We adopted an earlier reported Monte-Carlo-based estimation system for IR and simulated the dose in a geometrical area resembling an IR room with fluoroscopic conditions. Users of our VR system experienced a simulated air dose distribution in the IR room while the irradiation angle, irradiation timing, and lead shielding were controlled. The estimated air dose was evaluated through comparison with measurements taken using a radiophotoluminescence glass dosimeter. Our dose estimation results were consistent with dosimeter readings, showing a 13.5% average mutual difference. The estimated air dose was visualized in VR: users could view a virtual IR room and walk around in it. Using our VR system, users experienced dose distribution changes dynamically with C-arm rotation. Qualitative tests were conducted to evaluate the workload and usability of our VR system. The perceived overall workload score (18.00) was lower than the scores reported in the literature for medical tasks (50.60) and computer activities (54.00). This VR visualization is expected to open new horizons for understanding dose distributions intuitively, thereby aiding the avoidance of radiation injury.
Purpose: The principal aim of this study was to evaluate radiation exposure of interventionalists during computed tomography (CT) fluoroscopy-guided percutaneous cryoablation (PCA) using radiophotoluminescent glass dosimeters (RPLDs). The radioprotective effects of safety glasses and lead apron were also evaluated.
Materials and Methods: Radiation exposure of interventionalists during 46 CT fluoroscopy-guided PCA procedures was evaluated. Entrance surface dose (ESD) was measured using RPLDs on multiple sites: five sites, representing eye lens exposure; five sites, representing body exposure; and four sites, representing skin exposure. The ESD values on multiple sites were compared between different PCA procedures (renal, liver, and bone).
Results: The mean ESD on the X-ray-side hand exhibited the highest value (358.8 μGy). Regarding evaluation sites representing exposure to the eye lens, the highest ESD inside the radiation protective glasses was detected on the X-ray-side cheek (167.1 μGy). Most ESD values among multiple sites (10/14) were linearly correlated with CT fluoroscopy time. Among them, the ESD values measured during renal and liver PCA were relatively higher than those measured during bone PCA, especially on the chest area outside the lead apron, and on the X-ray tube-side elbow and hand during renal and bone PCA. Radioprotective effects of safety glasses and lead apron ranged from 44.6 to 50.6% and from 30.2 to 79.6%, respectively, on each evaluation site.
Conclusion: The site with the highest radiation exposure on interventionalists during CT fluoroscopy-guided PCA was the X-ray tube-side hand. Radiation exposure of interventionalists was at acceptable levels and consistent with the recommended dose limits.
Purpose: We aimed to investigate the long-term outcomes of patients undergoing hybrid catheter intervention for acute massive pulmonary thromboembolism.
Material and Methods: Twenty-five patients with hemodynamic impairment were treated with mechanical thrombus fragmentation, an intrapulmonary injection of mt-PA, and manual clot aspiration between August 1999 and June 2002. All patients were discharged after the procedure. Patients' statuses were checked by medical record examinations and telephone interviews. The median follow-up was 141 months (115-168 months).
Results: Ten patients died during follow-up, five for malignancy, three for septic shock, one for cerebral infarction, and one for heart failure. One patient had recurrence of pulmonary thromboembolism because of drug withdrawal by self-judgment. No chronic pulmonary thromboembolism was observed. The 1-year, 5-year, and 10-year survival rates were 87.5 ±6.8%, 83.3±7.6%, and 74.5±9.0%, respectively.
Conclusion: Patients who undergo hybrid catheter intervention for acute massive pulmonary thromboembolism show good long-term outcomes.
We describe three cases of renal cell carcinoma (RCC) with recurring local tumor progression, i.e., local failure following repeat cryoablation for a locally progressed tumor. A second local progression developed in all cases after cryoablation for the first local progression, despite there being a sufficiently large ice-ball margin. In two cases, the second local progression was treated with microwave ablation and controlled in the follow-up. In one case, a third cryoablation was performed, but a third local progression developed after 12 months. These cases suggest that some RCCs may be refractory to cryoablation. In cases of recurring local progression, switching from cryoablation to another ablation modality may be an alternative.
Here, we report a case of hepatocellular carcinoma detected on computed tomography and treated with laparoscopic anatomical liver resection in a 69-year-old woman who was being followed-up for hepatitis C. Intraoperative liver segmentation is necessary to accomplish laparoscopic anatomical liver resection. Therefore, the day before surgery, hepatic artery embolization was performed with an indocyanine green-Lipiodol® mixture and Gelpart® containing indocyanine green to mark the region for hepatectomy. The next day, surgeons visually confirmed the resection segments on indocyanine green fluorescence imaging and performed laparoscopic anatomical liver resection. No major complications resulted from this method. In conclusion, hepatic artery embolization with an indocyanine green-Lipiodol® mixture is effective and safe for liver segment identification during laparoscopic anatomical liver resection.
A 54-year-old Japanese woman, hospitalized for recurrent chronic alcoholic pancreatitis, manifested bloody stools. An esophagogastroduodenoscopy revealed active bleeding from the papilla of Vater. Contrast-enhanced computed tomography (CECT) revealed a pseudoaneurysm in the pancreatic pseudocyst (hemosuccus pancreaticus). Angiography demonstrated pseudoaneurysm of the dorsal pancreatic artery branch. We selected N-butyl-2-cyanoacrylate (NBCA) as an embolus material because of the existing coagulopathy and difficulty in selecting the arterial branch. The administered NBCA outflowed into the pancreatic duct over the pseudoaneurysm. However, transcatheter arterial embolization (TAE) was successful, and no complication or rebleeding was observed after TAE. CECT showed NBCA cast in the pancreatic duct; however, the chronic pancreatitis improved. NBCA may be used to regulate hemosuccus pancreaticus in emergency settings; however, interventional radiologists must carefully consider the complications caused by NBCA.
The purpose of this report was to describe the reorientation of the chimney graft technique to downsize brachial artery access during thoracic endovascular aortic repair and thus preserve left subclavian artery flow. In the case described herein, the chimney graft was advanced not from the brachial or axillary artery, but from the common femoral artery, over a brachiofemoral pull-through wire. The chimney graft was then turned out into the ascending aorta by balloon dilatation via percutaneous brachial access ( "reorientation" ). Despite the use of a large-diameter chimney graft, the chimney technique with percutaneous brachial access was successfully performed using the reorientation technique.
Purpose: To evaluate the outcomes of radiofrequency ablation (RFA) on lung tumors < 1 cm in maximum diameter.
Materials and Methods: Twenty-eight patients (12 male, 16 female; median age, 59 years; mean age, 58 ± 16 years; range, 16-78 years) who underwent RFA for lung tumors < 1 cm in diameter between November 2009 and September 2018 were included in this study. Thirty-five tumors (median size, 8.4 mm; mean size, 7.7 ± 1.9 mm; range, 3.6-9.9 mm) were treated with 33 sessions of RFA. Technique efficacy and safety were subsequently evaluated. Initial and secondary technique efficacy were defined as complete ablation without residual tumor or local tumor progression after initial and repeat RFA, respectively. Safety was evaluated according to the Common Terminology Criteria for Adverse Events, version 5.0.
Results: Residual tumor remained for 1 tumor (3%, 1/35) and local tumor progression was found in 2 tumors (6%, 2/35). Initial technique efficacy rate was therefore 91% (32/35). The remaining 3 tumors were treated by repeat RFA (secondary technique efficacy rate: 100%, 35/35). Initial technique efficacy rate was significantly lower for tumors treated with starting energy ≥ 20 W (P = 0.02) and showing a quick increase in tissue impedance (P = 0.01). There were 4 grade 2 adverse events (12%, 4/33) comprising pneumothorax requiring chest tube placement, and 14 grade 1 adverse events comprising self-limiting pneumothorax (36%, 12/33) and pulmonary parenchymal hemorrhage (6%, 2/33).
Conclusion: To achieve good outcomes for lung tumors < 1 cm, radiofrequency energy should be started at < 20 W. Application of manual mode ablation might be considered when delivery of power cannot be continued due to a quick increase in tissue impedance.