Percutaneous Computed Tomography–guided Renal Mass Radiofrequency Ablation versus Cryoablation: Doses of Sedation Medication Used

PurposeTo compare the amount of sedation medication administered during radiofrequency (RF) ablation versus cryoablation of small renal masses.Materials and MethodsRecords were retrospectively reviewed in patients who underwent percutaneous computed tomography–guided RF ablation and cryoablation of small renal masses from January 2002 to June 2011 for patient and tumor characteristics, amount of medications used for moderate sedation, and complications. Sedation was performed by giving patients titrated doses of midazolam and fentanyl. Additional medications were given if the desired level of sedation was not achieved.ResultsThere were 116 patients who underwent 136 ablation procedures; 71 patients underwent RF ablation, and 65 patients underwent cryoablation. RF ablation was associated with a significantly higher mean dose of fentanyl (mean dose for RF ablation, 236.43 μg; mean dose for cryoablation, 172.27 μg; P<.001). RF ablation was also associated with a higher mean dose of midazolam (mean dose for RF ablation, 4.5 mg; mean dose for cryoablation, 3.27 mg; P<.001). In the RF ablation group, two patients required additional sedation with droperidol. As a result of oversedation, two patients in the RF ablation cohort required sedation reversal with naloxone and flumazenil. None of the patients who underwent cryoablation required sedation reversal. No other sedation-related complications occurred.ConclusionsCryoablation of small renal masses was performed with less sedation medication than RF ablation. This finding suggests renal cryoablation is less painful than RF ablation; however, prospective studies with validated pain scales are needed to confirm these results.     

Complications following 573 percutaneous renal radiofrequency and cryoablation procedures

PurposeTo review complications related to percutaneous renal tumor ablation.Materials and MethodsProspectively collected data related to renal radiofrequency (RF) ablation and cryoablation procedures performed from May 2000 through November 2010 were reviewed. This included 573 renal ablation procedures performed in 533 patients to treat 633 tumors. A total of 254 RF ablation and 311 cryoablation procedures were performed; eight patients underwent simultaneous RF ablation and cryoablation. The mean age of patients at the time of the procedure was 70 years (range, 24–93 y), and 382 of 573 procedures (67%) were performed in male patients. Complications were recorded according to the Clavien–Dindo classification scheme. Duration of hospitalization was also documented.ResultsOf the 573 procedures, 63 produced complications (11.0% overall complication rate). There were 66 reported complications, of which 38 (6.6% of total procedures) were Clavien–Dindo grade II–IV major complications; there were no deaths. Major complication rates did not differ statistically (P = .15) between cryoablation (7.7%; 24 of 311) and RF ablation (4.7%; 12 of 254). Of the complications related to cryoablation, bleeding and hematuria were most common. Bleeding during cryoablation was associated with advanced age, increased tumor size, increased number of cryoprobes, and central position (P < .05). Of those treated with RF ablation, nerve and urothelial injury were most common. Mean hospitalization duration was 1 day for RF ablation and cryoablation.ConclusionsComplications related to percutaneous renal ablation are infrequent. Recognition of potential complications and associated risk factors can allow optimization of periprocedural care.     

Sedations and analgesia in patients undergoing percutaneous transhepatic biliary drainage

AIM: To present our experience using intravenous sedoanalgesia for percutaneous biliary drainage. MATERIALS AND METHODS: This study comprised 100 patients, all of whom were continuously monitored [electrocardiogram (ECG), blood pressure, pulse oxymetry] and received an initial dose of 2mg midazolam followed by 0.02 mg fentanyl. Before every anticipated painful procedure, a maintenance dose of 0.01 mg fentanyl was administered. If the procedure continued and the patient became aware, another 1mg midazolam was given. This was repeated if patients felt pain. A total dose of 0.08 mg fentanyl and 7 mg midazolam was never exceeded. Immediately after the procedure, the nurse was asked to evaluate patients' pain score. The patients were asked 3h later to complete a visual 10-degree pain score scale. RESULTS: The average dose of fentanyl and midazolam was 0.042 mg (0.03-0.08 mg) and 4.28 mg (2-7 mg), respectively. Only one patient recorded the procedure as painful. The scores given by the attending nurse (1-7 points, mean 2.9) correlated well with those given by the patients (1-6 points, mean 2.72). No complications were noted. CONCLUSION: According to our experience, interventional radiologists practising biliary procedures can administer low doses of midazolam and minimize the doses of fentanyl, without loss of adequate sedation and analgesia.     

Impact on renal function of percutaneous thermal ablation of renal masses in patients with preexisting chronic kidney disease

PurposeTo examine the effect of percutaneous thermal ablation of renal masses on renal function among patients with baseline chronic kidney disease (CKD).Materials And MethodsPatients with baseline CKD (initial glomerular filtration rate [GFR] < 60 mL/min/1.73 m²) who underwent percutaneous cryoablation or radiofrequency (RF) ablation of renal masses were reviewed.ResultsA total of 48 patients with a GRF of 60 mL/min/1.73 m² or lower were treated with renal cryoablation or RF ablation and had follow-up GFR measurement 1 month afterward. Mean patient age was 73 years (range, 47–89 y). Cryoablation was performed in 22 patients and RF ablation was performed in 26. Mean tumor diameter was 3.4 cm (range, 0.9–10.2 cm). Mean overall GFRs were 39.8 mL/min/1.73 m² at baseline and 39.7 mL/min/1.73 m² at 1 month after ablation (P = .85). A total of 38 patients had 1-year follow-up GFR measurement (cryoablation, n = 18; RF ablation, n = 20), and their mean GFR was 40.9 mL/min/1.73 m² ± 11.4 (SD), compared with a preablation GFR of 41.2 mL/min/1.73 m²(P = .79). In the cryoablation group, mean GFRs at 1 month and 1 year were 41.4 mL/min/1.73 m² and 44.4 mL/min/1.73 m², compared with respective baseline GFRs of 41.1 mL/min/1.73 m² and 42.1 mL/min/1.73 m² (P = .75 and P = .19, respectively). In the RF ablation group, mean GFRs at 1 month and 1 year were 38.2 mL/min/1.73 m² and 37.8 mL/min/1.73 m², compared with respective baseline GFRs of 38.7 mL/min/1.73 m² and 40.4 mL/min/1.73 m² (P = .58 and P = .09, respectively).ConclusionsIndependent of ablation modality, percutaneous renal mass ablation does not appear to affect renal function among patients with CKD.     

Renal tumors: MR imaging-guided percutaneous cryotherapy--initial experience in 23 patients

PURPOSE: To evaluate the initial clinical experience of magnetic resonance (MR) imaging-guided percutaneous cryotherapy of renal tumors. MATERIALS AND METHODS: Twenty-six renal tumors (diameter range, 1.0-4.6 cm; mean, 2.6 cm) in 23 patients were treated with 27 cryoablation procedures by using a protocol approved by the human subjects committee at the authors' institution. The study complied with the Health Insurance Portability and Accountability Act. Written informed consent was obtained from each patient. There were 17 men and six women with an average age of 66 years (range, 43-86 years). Of 26 masses, 24 were renal cell carcinoma, one was a transitional cell carcinoma, and one was an angiomyolipoma. By using a 0.5-T open MR imaging system and general anesthesia in patients, one to five (mean, 2.4) needlelike cryoprobes were placed and lesions were ablated by using real-time MR imaging for intraprocedural monitoring of ice balls. Tumors were considered successfully ablated if they demonstrated no contrast enhancement at follow-up computed tomography or MR imaging (mean, 14 months; range, 4-30 months). RESULTS: Twenty-four of 26 tumors were successfully ablated, 23 of which required only one treatment session. Two complications occurred in a total of 27 cryoablations: one hemorrhage, which required a blood transfusion, and one abscess, which was treated successfully with percutaneous catheter drainage. CONCLUSION: MR imaging-guided percutaneous cryotherapy of renal tumors shows promise for the treatment of selected small renal tumors, and MR imaging can be used to monitor the treatment intraprocedurally. This technique may prove useful for ablation of renal tumors completely in one session, but long-term follow-up is needed.     

Percutaneous radiofrequency ablation of renal tumors: technique, complications, and outcomes

PURPOSE: To report the safety, technical success, and effectiveness of percutaneous radiofrequency (RF) ablation for renal tumors. MATERIALS AND METHODS: The authors retrospectively reviewed the medical records and imaging studies of 29 consecutive patients (18 men, 11 women; mean age, 65 +/- 2.62 years) with 30 renal tumors (mean diameter, 3.5 +/- 0.24 cm) who underwent percutaneous RF ablation at their institution from September 2001 to March 2004. All procedures were performed with computed tomography guidance with general anesthesia, and all patients were admitted to the hospital for overnight observation. Technical success, complications, and their management were recorded. Technique effectiveness was assessed by imaging and clinical follow up. RESULTS: Overall, 88 overlapping ablations were performed (mean, 2.6 +/- 0.16 ablations per tumor per session) in 34 sessions. There were four major complications (12%). Three patients had gross hematuria and urinary obstruction, all were successfully treated. One patient had persistent anterior abdominal wall weakness. There were also two minor complications (6%) without significant clinical sequelae. One patient had gross hematuria which resolved spontaneously, another patient had transient paresthesia of the anterior abdominal wall. There were no significant changes in renal function after RF ablation. The intent of RF ablation was eradication of the primary tumor in 27 patients and treatment of gross hematuria in the other two. Technical success was achieved in all cases. Follow-up images were available for 26 patients. The primary tumor was completely ablated in 23 of 24 patients (96%) in whom eradication of the primary tumor was attempted (follow up period: mean, 10 months, median 7 months). The two patients treated for hematuria remained asymptomatic for 6 and 27 months each. CONCLUSION: Percutaneous RF ablation for renal tumors is safe and well tolerated. High technical success rates are expected. Early reports of the technique's effectiveness are promising.     

Percutaneous ablation of renal tumors: radiofrequency ablation or cryoablation?

Percutaneous ablation of renal tumors, including radiofrequency ablation and cryoablation, are increasingly being used for small tumors as an alternative to surgery for poor surgical candidates. Compared to radiofrequency ablation, cryoablation has several advantages: improved volume control and preservation of adjacent structures due to the excellent depiction of the ice ball on CT and MRI; better protection of the collecting system for central tumor with reduced risk of postprocedural urinary fistula. The main pitfall of cryoablation is the higher cost. Therefore, cryoablation should be reserved for the treatment of complex tumors. In this article, we will review the different steps of percutaneous renal tumor ablation procedures including patient selection, technical considerations, and follow-up imaging.     

Percutaneous Cryoablation of the Horseshoe Kidney: An Initial Experience

Between June 2006 and January 2016, 6 renal cryoablation procedures were performed in 5 patients with horseshoe kidneys. Renal cell carcinoma (RCC) accounted for 5 of the tumors, and the sixth was a carcinoid tumor. All 6 procedures were technically successful. The patient with the carcinoid tumor developed local tumor progression 38 months after ablation. Technique effectiveness was achieved in all 5 patients with RCC. Two complications occurred: obstructive hematuria and transient inguinal neuralgia after ablation. In this small initial experience, percutaneous cryoablation appears feasible in treatment of primary tumors in horseshoe kidneys.     

Unresectable pulmonary malignancies: CT-guided percutaneous radiofrequency ablation--preliminary results

PURPOSE: To assess whether percutaneous radiofrequency (RF) ablation of unresectable pulmonary malignancies is safe and technically feasible and to evaluate the usefulness of computed tomographic (CT) nodule densitometry as a tool for following up tumors after ablation. MATERIALS AND METHODS: Twelve patients (seven men and five women; mean age, 60.6 years) with unresectable disease (because of poor lung reserve or multifocality) underwent nodule CT densitometry and CT-guided percutaneous RF ablation of 19 lung tumors (six [32%] tumors were adenocarcinoma, one (5%) was large cell carcinoma, two (10%) were bronchoalveolar carcinoma, four (21%) were colorectal carcinoma, and six (32%) were sarcoma less than 50 cm2 in area (range, 0.25-35.00 cm2). No patients had symptoms of their disease before RF ablation. Follow-up CT densitometry was scheduled for 1, 3, 6, and 12 months after RF ablation. Lesions were evaluated for change in area and contrast enhancement at follow-up CT. RESULTS: RF ablation was well tolerated by all patients. Intraprocedural complications included 12 cases of pneumothoraces (two patients required chest tube placement, while 10 were asymptomatic and required no further treatment), two cases of pleural effusion, and two cases of moderate pain (one case during and one case both during and after the procedure). Mean follow-up was 4(1/2) months (range, 1-12 months). In the eight patients with 3-month follow-up, lesion size increased in two and remained stable in six. Mean contrast enhancement, however, decreased from 46.8 HU (range, 19-107 HU) at baseline to 9.6 HU (range, 0-32 HU) at 1-2-month follow-up. In the one patient with 12-month CT densitometry follow-up, lesion enhancement was less than 50% of that at baseline, and lesion diameter remained stable. CONCLUSION: These preliminary results show that percutaneous RF ablation is a safe and technically feasible management option for unresectable pulmonary malignancies. CT densitometry may have potential for future use as a noninvasive method of following up tumors after RF ablation.     

Radiofrequency Ablation,Cryoablation, and Microwave Ablation for T1a Renal Cell Carcinoma: A Comparative Evaluation of Therapeutic and Renal Function Outcomes

PurposeTo compare the therapeutic and renal function outcomes of radiofrequency (RF) ablation, cryoablation, and microwave (MW) ablation for treatment of T1a renal cell carcinoma (RCC).Materials and MethodsA retrospective assessment of 297 patients (mean age 72 years range 24–90 years) with biopsy-proven RCC treated with image-guided percutaneous thermal ablation was performed between October 2006 and December 2016. Mean tumor size was 2.4 cm; mean radius, exophytic/endophytic properties, nearness of tumor to collecting system or sinus, anterior/posterior, hilar tumor touching the main renal artery or vein, and location relative to polar lines; Preoperative Aspects and Dimensions Used for an Anatomical; and c-centrality scores were 6.0, 7.0, and 2.8, respectively. Assessments of adverse events, treatment efficacy, and therapeutic outcomes were performed among RF ablation, cryoablation, and MW ablation. The 2-year disease-free, metastatic-free, and cancer-specific survival rates were tabulated. Estimated glomerular filtration rate was used to assess for treatment related changes in renal function.ResultsA total of 297 T1aN0M0 biopsy-proven RCCs measuring 1.2–3.9 cm were treated with computed tomography–guided RF ablation (n = 244, 82%), cryoablation (n = 26, 9%), and MW ablation (n = 27, 9%). There were no significant differences in patient demographics among the 3 groups (P = .09). Technical success rates were similar among the 3 treatments (P = .33). Primary efficacy at 1 month postablation was more likely to be achieved with RF ablation and MW ablation than with cryoablation. At 2 years’ follow-up, there was no local recurrence, metastatic progression, or RCC-related death observed in the 3 groups. There was no significant change in estimated glomerular filtration rate among the 3 ablation groups compared with baseline at 2-year follow-up (P = .71).ConclusionRF ablation, cryoablation, and MW ablation are equivalent at 2 years for treatment of T1a RCC for therapeutic outcome, stability of renal function, and low adverse event rate.     

Percutaneous radiofrequency ablation of renal tumors: midterm results in 16 patients

PURPOSE: To evaluate the outcome of 16 patients after percutaneous radiofrequency ablation of renal tumors. MATERIALS AND METHODS: Sixteen patients (nine women, seven men; mean age, 61+/-9 years) with 24 unresectable renal tumors (mean volume, 4.3+/-4.3 cm3) underwent CT-guided (n=20) or MR imaging-guided (n=4) percutaneous radiofrequency ablation using an expandable electrode (Starburst XL, RITA Medical Systems, Mountain View, CA) with a 150-W generator. The initial follow-up imaging was performed within 1-30 days after RF ablation, then at 3-6 month intervals using either CT or MRI. Residual tumor volume and coagulation necrosis was assessed, and statistical correlation tests were obtained to determine the strength of the relationship between necrosis volume and number of ablations. RESULTS: Overall, 97 overlapping RF ablations were performed (mean, 3.5+/-1.5 ablations per tumor) during 24 sessions. Five or more RF ablations per tumor created significant larger necrosis volumes than 1-2 (p=.034) or 3-4 ablations (p=.020). A complete ablation was achieved in 20/24 tumors (primary technical success, 83%; mean volume of coagulation necrosis: 10.2+/-7.2 cm3). Three of four residual tumors were retreated and showed complete necrosis thereafter. Three major complications (one percuatneous urinary fistula and two ureteral strictures) were observed after RF ablation. No further clinically relevant complications were observed and renal function remained stable. During a mean follow-up of 11.2 months (range, 0.2-31.5), 15/16 patients (94%) were alive. Only one patient had evidence of local recurrent tumor. CONCLUSION: The midterm results of percutaneous RF ablation for renal tumors are promising and show that RF ablation is well-suited to preserve renal function.     

Small hepatocellular carcinoma: treatment with radio-frequency ablation versus ethanol injection

PURPOSE: To compare the effectiveness of radio-frequency (RF) ablation with that of percutaneous ethanol injection in the treatment of small hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Eighty-six patients with 112 small (< or = 3-cm-diameter) HCCs underwent RF ablation (42 patients with 52 tumors) or percutaneous ethanol injection (44 patients with 60 tumors). Therapeutic efficacy was evaluated with dual-phase spiral computed tomography performed at least 4 months after treatment. RESULTS: Complete necrosis was achieved in 47 of 52 tumors with RF ablation (90%) and in 48 of 60 tumors with percutaneous ethanol injection (80%). These results were obtained with an average of 1.2 sessions per tumor with RF ablation and 4.8 sessions per tumor with percutaneous ethanol injection. One major complication (hemothorax that required drainage) and four minor complications (intraperitoneal bleeding, hemobilia, pleural effusion, cholecystitis) occurred in patients treated with RF ablation; no complications occurred in patients treated with percutaneous ethanol injection. CONCLUSION: RF ablation results in a higher rate of complete necrosis and requires fewer treatment sessions than percutaneous ethanol injection. However, the complication rate is higher with RF ablation than with percutaneous ethanol injection. RF ablation is the treatment of choice for most patients with HCC.     

A Single-Institution Experience in Image-Guided Thermal Ablation of Adrenal Gland Metastases

PurposeTo assess safety, technical success, local control, and survival associated with percutaneous image-guided adrenal ablation.Materials and MethodsAdult patients with adrenal metastases who underwent percutaneous image-guided adrenal ablation during the years 2003–2012 were identified. There were 32 patients with 37 adrenal tumors identified. Technical success, safety, local control, and survival were analyzed according to standard criteria.ResultsIn 32 patients (25 men and 7 women; mean age, 66 y; age range, 44–88 y) with 37 adrenal tumors, 35 ablation procedures were performed. One patient with an 8.2-cm tumor underwent planned cryoablation debulking fully anticipating untreated margins owing to close proximity of the pancreas (ie, the intent was to diminish tumor burden rather than a curative intervention). Of the 36 patients treated with curative intent, technical success was achieved in 35 (97%) tumors. Follow-up imaging was performed on 34 of 37 tumors (excluding patients with intentional debulking [n = 1], technical failure [n = 1], and absence of follow-up [n = 1]). Local recurrence developed in 3 (8.8%) of 34 tumors. Local tumor control was achieved in 31 lesions at a mean of 22.7 months of follow-up. Recurrence-free survival and overall survival at 36 months were 88% and 52%, respectively, with a median survival of 34.5 months. A Common Terminology Criteria for Adverse Events version 4 grade 3 or 4 complication was observed in three (8.6%) ablation procedures.ConclusionsImage-guided ablation is safe and effective for local control of metastatic adrenal tumors and provides a minimally invasive alternative to surgical resection in appropriately selected patients.     

Radio-frequency ablation of renal cell carcinoma: early clinical experience

PURPOSE: To report the authors' early experience with radio-frequency (RF) ablation of renal cell carcinoma. MATERIALS AND METHODS: Twenty-four percutaneous RF ablation treatments for nine tumors were performed in eight patients with renal cell carcinoma. Indications included coexistent morbidity, previous surgery, or solitary kidney in patients with a life expectancy shorter than 10 years. Smaller (3 cm) and/or central lesions (n = 6) were treated with cluster or multiple electrodes. Patients returned for a second treatment when follow-up imaging depicted tumor enhancement. Follow-up imaging was performed at 1 and 3 months and then at 6-month intervals, with a mean follow-up of 10.3 months. Seven patients were alive at least 6 months after their initial treatment. RESULTS: All five exophytic tumors were free of enhancement. One of three central tumors was free of enhancement. One tumor had both central and exophytic components and was free of enhancement. Three tumors were 3 cm or smaller and free of enhancement. Of the six tumors larger than 3 cm, four were free of enhancement. CONCLUSION: Percutaneous RF ablation is a promising treatment for select patients with renal cell carcinoma. The ultimate role of this modality will continue to evolve and warrants further study.     

冷冻消融治疗复发性盆腔和后腹肿瘤的应用

目的 探索CT定位经皮冷冻消融盆腔和后腹膜术后复发性肿瘤的安全性及疗效.方法 CT定位、引导经皮冷冻消融盆腔、后腹膜恶性肿瘤患者108例并作总结.结果 ①100例中9例为完全性冷冻消融,91例为姑息性冷冻消融.随访3～11年,1年生存率87％(87/100),3年生存率17％(17/100),5年生存率9％(9/100).冷冻后疼痛缓解率84％(70/83).②冷冻后1个月增强CT显示9例完全性消融:肿瘤冷冻区无强化.91例姑息性消融:消融率＞90％ 48例、80％～90％ 25例、70％～80％ 12例、60％～70％4例、＜60％3例.③并发症:术后局部感染3例,抗感染治疗后痊愈;直肠上段肠瘘1例,经肠造瘘后逐渐痊愈;术后短暂排尿困难5例,留置导尿3～5 d恢复;术后发热3～5 d;表皮冻伤3例,对症处理痊愈.结论 盆腔和后腹膜肿瘤术后局限性复发,CT引导冷冻消融较为安全,完全冷冻消融后对提升肿瘤局部控制,延长生存期获益明显.     

Hepatic Hilar Nerve Block for Adjunctive Analgesia during Percutaneous Thermal Ablation of Hepatic Tumors: A Retrospective Analysis

PurposeTo determine whether hepatic hilar nerve block techniques reduce analgesic and sedation requirements during percutaneous image-guided thermal ablation of hepatic tumors.Materials and MethodsA single-center retrospective cohort analysis was performed of 177 patients (median age, 67 years; range, 33–86 years) who underwent percutaneous image-guided thermal ablation of liver tumors. All patients were treated utilizing local anesthetic and moderate sedation between November 2018 and November 2021 at a tertiary level hospital, with or without the administration of a hepatic hilar nerve block. Univariable and multivariable linear regression analyses were performed to determine the relationship between the administration of the hilar nerve block and fentanyl and midazolam dosages.ResultsA total of 114 (64%) patients received a hilar nerve block in addition to procedural sedation, and 63 (36%) patients received procedural sedation alone. There were no significant differences in the baseline demographic and tumor characteristics between the cohorts. The procedure duration was longer in the hilar block cohort than in the unblocked cohort (median, 95 vs 82 minutes; P = .0012). The technical success rate (98% in both the cohorts, P = .93) and adverse event rate (11% vs 3%, P = .14) were not significantly different between the cohorts. After adjusting for patient and tumor characteristics, ablation modality, and procedure and ablation durations, hilar nerve blocks were associated with lower fentanyl (?18.4%, P = .0045) and midazolam (?22.7%, P = .0007) dosages.ConclusionsHepatic hilar nerve blocks significantly decrease the fentanyl and midazolam requirements during thermal ablation of hepatic tumors, without a significant change in the technical success or adverse event rates.     

Hepatic hemorrhage caused by percutaneous tumor ablation: radiofrequency ablation versus cryoablation in a porcine model

PURPOSE: To determine the extent of hepatic hemorrhage caused by percutaneous cryoablation performed with a small-diameter cryoablation probe compared with that caused by percutaneous radiofrequency (RF) ablation in a porcine model. MATERIALS AND METHODS: The study was pre-approved by the institutional research animal care and use committee, and husbandry and experiments complied with National Institutes of Health standards for care and use of laboratory animals. Percutaneous hepatic ablation was performed in 18 domestic pigs (mean weight, 45 kg) by using a 17-gauge (1.5-mm-diameter) RF electrode (n = 6), a cluster of three RF electrodes (n = 6), or a 13-gauge (2.4 mm-diameter) cryoprobe (n = 6). Ablation was performed in four sites per liver. Total blood loss, minimum lesion diameter, maximum lesion diameter, and lesion volume were determined for each group and compared by using analysis of variance. RESULTS: Mean blood loss was 11.11 mL +/- 11.47 (standard deviation), 105.29 mL +/- 175.58, and 28.06 mL +/- 30.97 with the single RF electrode, RF electrode cluster, and cryoablation probe, respectively. Mean minimum and maximum lesion diameters were largest with the RF electrode cluster (2.40 and 3.98 cm, respectively), followed by the cryoablation probe (2.38 and 3.94 cm) and single RF electrode (1.49 and 2.63 cm). Mean minimum and maximum lesion diameters were significantly different between the single RF electrode and the RF electrode cluster, as well as between the single RF electrode and the cryoablation probe (P < .001). Mean lesion volume was largest for the RF electrode cluster (24.03 cm3), followed by those for the cryoablation probe (17.46 cm3) and single RF electrode (9.05 cm3) (single RF electrode vs cryoablation probe, P < .05). Lesion volumes were not significantly different with the RF electrode cluster versus the single RF electrode (P = .052) or with the RF electrode cluster versus the cryoablation probe (P = .381). CONCLUSION: Mean blood loss from percutaneous cryoablation in this model was between that for RF ablation with the single electrode and that for RF ablation with the electrode cluster.     

Percutaneous radiofrequency ablation of hepatic tumors against the diaphragm: frequency of diaphragmatic injury

PURPOSE: To retrospectively determine the frequency of diaphragmatic injury when percutaneous hepatic radiofrequency (RF) ablation is performed adjacent to the diaphragm. MATERIALS AND METHODS: Institutional Review Board approval was obtained for our HIPAA-compliant study. Informed consent for the ablation procedure and for use of related data for future research was obtained from each patient. A retrospective review was conducted of 215 patients undergoing percutaneous RF ablation of hepatic tumors. Twenty-nine patients (21 men and eight women; age, 41-89 years) were identified with tumors abutting the diaphragm. Episodes of right shoulder pain were recorded. A panel of radiologists blinded to the patients' clinical histories reviewed their imaging for evidence of diaphragmatic injury and ablation success. A generalized estimating equation model and the Fisher exact test were used for statistical analysis. RESULTS: The 29 patients had a total of 33 tumors abutting the diaphragm. Tumor size was 1.3-5.5 cm (mean, 3.2 cm +/- 1.1). After ablation, five (17%) patients reported right shoulder pain. In four, pain was mild or moderate, with symptoms lasting 2-14 days (median, 5.5 days). Three of these showed diaphragmatic thickening on postablation computed tomographic (CT) scans. One patient had severe pain lasting 2 weeks, followed by milder pain for 2 months. This patient's postablation CT images showed focal nodular diaphragmatic thickening. This patient was treated with a multitined device; the other four, with straight-needle devices. Local tumor progression was seen in 14 tumors (42.4%). Tumors 3 cm or smaller had a much lower local progression rate than tumors larger than 3 cm (12.5% vs 70.6%). CONCLUSION: Of 29 patients who had ablation of hepatic tumors adjacent to the diaphragm, five (17%) had diaphragmatic injury, which was clinically apparent with right shoulder pain.     

Radiofrequency ablation of osteoid osteoma: initial results with a bipolar ablation device

PURPOSE: To report the initial results with percutaneous radiofrequency (RF) ablation of osteoid osteomas with a bipolar ablation device. MATERIALS AND METHODS: Twelve patients (seven male patients and five female patients; mean age, 17.3 years; age range, 6-36 y) with clinically and radiologically suspected osteoid osteoma were treated with computed tomography-guided percutaneous bipolar RF ablation. The procedure was performed with the patients under general anesthesia. After localization of the nidus, an 11-gauge hollow drill was introduced into the nidus through a 9-F introducer sheath. A bipolar 18-gauge RF probe with a 9-mm active tip was inserted through the introducer sheath and connected to the RF generator. Energy application was started at 2 W and subsequently increased to a maximum of 5 W. The procedure was terminated if a resistance of 900 Omega was reached. RESULTS: Mean duration of energy deposition was 8.3 +/- 4.0 minutes, with a mean energy application of 1.8 +/- 2.9 kJ (range, 0.3 - 7 kJ). In one patient, the intervention had to be repeated twice to achieve total pain relief. Eleven of 12 patients (92%) remained free of symptoms at a follow-up time of 15.1 +/- 9.5 months (range, 5 - 31 months). One patient had recurrence of pain 16 months after the procedure and was treated surgically. No complications occurred. Patients resumed normal activity within 24 hours. CONCLUSIONS: Percutaneous bipolar RF ablation is an efficient and safe treatment of osteoid osteoma. Short-term efficacy of bipolar RF ablation may rival the results of monopolar RF ablation. Further studies are needed to address the long-term efficacy of this technique.     

Inflammatory nodules mimic applicator track seeding after percutaneous ablation of renal tumors

OBJECTIVE: The objective of our study was to report the occurrence of benign inflammatory nodules that develop in or near applicator tracks after percutaneous radiofrequency ablation and cryoablation of renal tumors. CONCLUSION: Benign inflammatory nodules occur rarely after percutaneous ablation of renal tumors and may mimic tumor seeding of the applicator track.