MRI-guided percutaneous cryoablation of renal tumors: use of external manual displacement of adjacent bowel loops

PURPOSE: We sought to investigate retrospectively the safety and effectiveness of using external hand compression to displace adjacent bowel loops during MRI-guided percutaneous cryoablation of renal tumors. MATERIALS AND METHODS: Fourteen patients (six women, eight men; mean age: 72 years) with 15 renal tumors (mean diameter: 2.4 cm; range: 1.4-4.6 cm) adjacent to bowel were treated with MRI-guided percutaneous cryoablation during which bowel was displaced manually. Bowel loop of concern was ascending colon (n=5), descending colon (n=8), descending colon and small bowel (n=1), ascending colon and small bowel (n=1). To analyze effectiveness of the maneuver, mean distance between tumor margin and bowel before and after the maneuver were compared and analyzed using paired Student's t-test. Minimum distance between iceball edge and adjacent bowel with external manual displacement during freezing was also measured. Safety was assessed by analyzing post-procedural MR imaging for adjacent bowel wall thickening and focal fluid collections as well as patients' clinical and imaging follow-up. RESULTS: Mean distance between tumor margin and closest adjacent bowel increased from 0.8 cm (range: 0-2 cm) before external manual compression to 2.6 cm (range: 1.6-4.1 cm) with manual displacement (p<0.01). Mean minimum distance between iceball edge and closest adjacent bowel during the procedures was 1.6 cm (range: 0.5-3.5 cm). No evidence of bowel injury was encountered. Twelve of 15 tumors had follow-up (mean: 10 months) that showed no tumor recurrence. CONCLUSION: MRI-guided percutaneous cryoablation of renal tumors adjacent to bowel can be done safely and effectively using external hand compression to displace bowel loops.     

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.     

Percutaneous radiofrequency ablation of renal cell carcinoma: preliminary results

PURPOSE: To report early results in percutaneous radiofrequency ablation (RFA) of renal cell carcinoma with an expandable RF probe. MATERIAL AND METHODS: In 14 patients (9 male, mean age 67.9 +/- 9.9 years) CT-guided percutaneous radiofrequency ablation of 15 renal cell carcinomas was performed using an expandable LeVeen probe (diameter 2-4 cm) and a 200-watt generator under general anesthesia and CT control. Tumors exceeding a diameter of 3 cm (n=6) were embolized within 24 h prior to RFA. Average tumor size was 3.0 +/- 1.0 cm. RESULTS: RFA was technically successful in all patients, resulting in a mean size of necrosis of 3.7 +/- 0.7 cm. With the exception of one reno-cutaneous fistula, which was successfully treated conservatively, no major complications were observed. No local recurrence was observed (follow-up: 13.9 +/- 12.4 months) while extrarenal tumor progression occurred in four patients. CONCLUSION: Our preliminary data suggest that nephron sparing percutaneous RFA of renal tumors with an expandable RF probe is safe and effective.     

Recurrent hepatocellular carcinoma: percutaneous radiofrequency ablation after hepatectomy

PURPOSE: To evaluate the therapeutic efficacy and safety of percutaneous radiofrequency (RF) ablation for recurrent hepatocellular carcinoma (HCC) in the liver after hepatectomy. MATERIALS AND METHODS: Forty-five patients with 53 recurrent HCC tumors in the liver underwent percutaneous RF ablation with ultrasonographic guidance. All patients had a history of hepatic resection for HCC. The mean diameter of recurrent tumors was 2.1 cm (range, 0.8-4.0 cm). All patients were followed up for at least 10 months after ablation (range, 10-40 months; mean, 23 months). Therapeutic efficacy and complications were evaluated with multiphase helical computed tomography (CT) at regular follow-up visits. Overall and disease-free survival rates were calculated. RESULTS: At follow-up CT after initial RF ablation, 11 (21%) of 53 ablated HCC tumor sites showed residual tumor or local tumor progression. After additional RF ablation, complete ablation of 46 (87%) of 53 tumors was attained. Also at initial follow-up CT, before either additional RF ablation or other treatment was performed, 21 (47%) of 45 patients were found to have 41 new HCC tumors at other liver sites. Of these, nine tumors in eight patients were treatable with a second application of RF ablation. Overall survival rates at 1, 2, and 3 years were 82%, 72%, and 54%, respectively. No deaths or complications requiring further treatment occurred as a result of RF ablation. CONCLUSION: Percutaneous RF ablation is an effective and safe method for treating recurrent HCC in the liver after hepatectomy, with a good overall patient survival rate.     

Therapeutic response assessment of percutaneous radiofrequency ablation for hepatocellular carcinoma: utility of contrast-enhanced agent detection imaging

PURPOSE: To assess the utility of contrast-enhanced agent detection imaging (ADI) in the assessment of the therapeutic response to percutaneous radiofrequency (RF) ablation in patients with hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Ninety patients with a total of 97 nodular HCCs (mean, 2.1+/-1.3 cm; range, 1.0-5.0 cm) treated with percutaneous RF ablation under the ultrasound guidance were evaluated with contrast-enhanced ADI after receiving an intravenous bolus injection of a microbubble contrast agent (SH U 508A). We obtained serial contrast-enhanced ADI images during the time period from 15 to 90 s after the initiation of the bolus contrast injection. All of the patients underwent a follow-up four-phase helical CT at 1 month after RF ablation, which was then repeated at 2-4 month intervals during a period of at least 12 months. The results of the contrast-enhanced ADI were compared with those of the follow-up CT in terms of the presence or absence of residual unablated tumor and local tumor progression in the treated lesions. RESULTS: On contrast-enhanced ADI, technical success was obtained in 94 (97%) of the 97 HCCs, while residual unablated tumors were found in three HCCs (3%). Two of the three tumors that were suspicious (was not proven) for incomplete ablation were subjected to additional RF ablation. The remaining one enhancing lesion that was suspicious of a residual tumor on contrast-enhanced ADI was revealed to be reactive hyperemia at the 1-month follow-up CT. Therefore; the diagnostic concordance between the contrast-enhanced ADI and 1-month follow-up CT was 99%. Of the 94 ablated HCCs without residual tumors on both the contrast-enhanced ADI and 1-month follow-up CT after the initial RF ablation, five (5%) had CT findings of local tumor progression at a subsequent follow-up CT. CONCLUSION: Despite its limitations in predicting local tumor progression in the treated tumors, contrast-enhanced ADI is potentially useful for evaluating the early therapeutic effect of percutaneous RF ablation for HCCs.     

Initial experience of percutaneous renal cryosurgery under the guidance of a horizontal open MRI system

OBJECTIVE: The aim of this study was to obtain preliminary results of cryoablation of renal tumors by using a percutaneous approach guided by a horizontal open MRI system, and to assess the safety and efficacy of this procedure. MATERIALS AND METHODS: Four patients with renal tumors underwent percutaneous cryosurgery with local anesthesia using a horizontal open MRI system (AIRIS II, Hitachi Medical Corp., Tokyo, Japan). The size of the mass was radiographically documented as 4 cm or less in diameter. A 2- or 3-mm cryoprobe was advanced into the renal mass under real-time MR monitoring. Growth of the iceball during cryoablation was monitored by two-dimensional MR images. Follow-up dynamic CT and physical examination were done after two weeks and six weeks. RESULT: MR imaging demonstrated the iceballs as sharply marginated regions of signal loss that expanded and engulfed the renal mass with clear contrast between the iceball and surrounding tissue. Cryoablated tumors resolved, and there were no serious complications and no clinically significant changes during the procedures and follow-up study. CONCLUSION: In this limited clinical trial of percutaneous renal tumor surgery, cryoablation demonstrated its feasibility with minimal morbidity. Intraprocedual MR-guided cryosurgery can be used as a safe modality, although further studies are necessary to determine the long-term efficacy of this procedure.     

Percutaneous Cryoablation of Small Hepatocellular Carcinoma with US Guidance and CT Monitoring: Initial Experience

The purpose of this study was to retrospectively determine the safety and effectiveness of percutaneous cryoablation, monitored with computed tomography (CT) and ultrasonographic (US) guidance, for the treatment of hepatocellular carcinoma (HCC). Four patients with small HCCs underwent one percutaneous cryoablation treatment session monitored with CT and US guidance. All patients underwent pretreatment blood chemistry testing and imaging evaluation. We treated lesions with simultaneous insertion of multiple 17-G cryoprobes (two or three) and defined technical success when the extension of a visible iceball was beyond 5 mm from the tumor margin. Intralesional enhancement or tumoral size increase was defined as local progression compared with that on images obtained immediately after ablation. We evaluated complications and follow-up (at 1, 3, and 6 months). All patients survived without short- or long-term complications. Cryoablation was technically successful in all patients at the end of the procedure. During follow-up two patients developed disease recurrence. One patient developed local tumor progression on the margin of the lesion; the other, a new HCC. In the case of local tumor progression a new elevation of α-fetoprotein (αFP) levels occurred at first follow-up control. In the other case levels of αFP remained stable during the first 3 months after the procedure, then demonstrated a progressive increase in αFP levels beginning at the fourth month, without tumor evidence during CT control at 3 months. We conclude that percutaneous cryotherapy with US guidance and CT monitoring is a feasible, safe, and effective for treatment of HCC. If local ablative procedures of hepatic lesions are to be performed, percutaneous cryoablation, not laparotomic, should be discussed as an alternative therapeutic measure. Longer follow-up should provide proof of the effectiveness of this technique.     

Breast Cryoablation in Patients with Bone Metastatic Breast Cancer

PurposeTo assess retrospectively the safety and feasibility of palliative breast cryoablation to treat primary breast tumors in patients with stage IV breast cancer.Materials and MethodsIn 17 female patients (mean age ± SD, 59 y ± 13; range, 37–81 y) with 22 bone metastatic ductal invasive breast lesions (2.5 cm × 1.6 cm ± 1.4 × 1.1; range, 1.0 cm × 0.5 cm to 6.7 cm × 5.5 cm), 19 computed tomography (CT)–guided percutaneous cryoablation sessions were performed for treatment of primary breast tumors. All patients had radiologic evidence (contrast-enhanced CT or magnetic resonance imaging) of persistence or progression of the primary breast cancer despite systemic therapy. The radiologic outcome was evaluated with a mean follow-up period of 13 months (range, 3–31 mo). Treatment of skeletal metastases was unnecessary during the follow-up period.ResultsAll of the cryoablation sessions were completed and well tolerated. Complete regression of the disease was achieved in 15 (88%) patients 2 months after the cryoablation. Two (12%) patients underwent a second cryoablation treatment because of a minimal persistence of viable tumor (residual disease). No relapse of primary tumors was observed on breast imaging during the follow-up period. One patient (6%) developed a new lesion localized to the contralateral breast.ConclusionsThese data suggest that palliative cryoablation of primary advanced breast cancer is a well-tolerated, feasible, and effective treatment option. Given the palliative effects of breast cryoablation demonstrated in this series, larger studies replicating these results are warranted.     

Percutaneous Cryoablation of Hepatic Tumors Adjacent to the Gallbladder: Assessment of Safety and Effectiveness

PurposeTo assess safety and effectiveness of percutaneous image-guided cryoablation of hepatic tumors adjacent to the gallbladder.Materials and MethodsTwenty-one cryoablation procedures were performed to treat 19 hepatic tumors (mean size, 2.7 cm; range, 1.0–5.0 cm) adjacent to the gallbladder in 17 patients (11 male; mean age, 59.2 y; range, 40–82 y) under computed tomography (n = 15) or magnetic resonance imaging (n = 6) guidance in a retrospective study. All tumors (mean size, 2.67 cm; range, 1.0–5.0 cm) were within 1 cm (mean, 0.4 cm) of the gallbladder; seven (33%) were contiguous with the gallbladder. Primary outcomes included complication rate and severity and postprocedure gallbladder imaging findings. Secondary outcomes included technical success and technique effectiveness at 6 months.ResultsComplications occurred in six of 21 procedures (29%); one (5%) was severe. Ice balls extended into the gallbladder lumen in 20 of 21 procedures (95%); no gallbladder-related complications occurred. The most common gallbladder imaging finding was mild, asymptomatic focal wall thickening after nine of 21 procedures (42%), which resolved on follow-up. Technical success was achieved in 19 of 21 sessions (90%). Six-month follow-up was available for 16 tumors; of these, all but two (87%) had no imaging evidence of local tumor progression.ConclusionsPercutaneous cryoablation of hepatic tumors adjacent to the gallbladder can be performed safely and successfully. Although postprocedural gallbladder changes are common, they are self-limited and clinically inconsequential, even when the ice ball extends into the gallbladder lumen.     

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.     

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.     

CT-monitored percutaneous cryoablation in a pig liver model: pilot study.

PURPOSE: To determine the safety and feasibility of percutaneous cryoablation with computed tomographic (CT) guidance in a pig liver model. MATERIALS AND METHODS: Nine angiographic balloons (mean diameter, 9 mm) were placed in the livers of seven domestic pigs (mean weight, 30.0 kg +/- 14.0 [SD]) as tumor-mimicking lesions. By using ultrasonographic and CT guidance, two 2.4- or 3.0-mm cryoprobes were placed flanking the balloon, and a 15-20-minute freezing process was performed. Hemostasis was achieved by placing absorbable cellulose fabric down the probe tract. After 24-96 hours, animals were sacrificed, and their livers were removed and were sectioned axially at 5-mm intervals for comparison with CT images. RESULTS: All animals survived the procedure without complication. No serious hemorrhage was found in any case. Ice balls were readily visualized at CT because they appeared as areas of decreased attenuation (1.0 HU +/- 20.7) when compared with areas of normal liver (48.2 HU +/- 6.3, P < .05). The mean ablative margin was 1.7 cm, and only one of nine cases, the one with probe failure, had a positive margin. Beam-hardening artifact from the metal probes was present but did not interfere with the procedure. Ice-ball size and shape corresponded closely to the area of necrosis determined at histopathologic analysis. CONCLUSION: CT-monitored percutaneous cryoablation is feasible and safe in this pig liver model.     

Percutaneous Cryoablation of Renal Tumors: Is It Time for a New Paradigm Shift?

Purpose

To retrospectively assess long-term outcomes of percutaneous renal cryoablation, including factors affecting complications and local recurrence rates.

Image-guided radiofrequency ablation of Bosniak category III or IV cystic renal tumors: initial clinical experience

The purpose of this study was to assess the efficacy of image-guided radiofrequency (RF) ablation of cystic renal tumors. Between November 2005 and August 2007, computed tomography (CT) or ultrasound-guided RF ablation was performed in nine patients with 14 Bosniak category III (n = 5) or IV (n = 9) cystic renal tumors using an internally cooled RF ablation system. We evaluated the number of sessions, cycles and duration of energy application, treatment results, lesion size change, and complications. Together the cystic renal tumors required 15 sessions and 23 cycles of energy application. The duration of energy application per one tumor ablation ranged from 1 to 12 min (mean 6 min). The last follow-up CT indicated complete coagulation of 14/14 (100%) lesions. None of these tumors had recurred within 1-19 months (mean 8 months). The maximum diameter of the cystic renal tumors was significantly reduced from 2.5 +/- 0.6 cm before ablation to 1.7 +/- 0.7 cm at the last follow-up CT (P < 0.01). Complications were pneumothorax (n = 2), inguinal paresthesia (n = 1), and arteriovenous fistula (n = 1). Image-guided RF ablation is an effective treatment for Bosniak category III or IV cystic renal tumors, which might need relatively shorter duration of energy application than purely solid renal tumors of the same size.     

CT引导下经皮穿刺适形冷冻消融治疗肺癌的临床分析

目的 探讨CT引导监测,经皮穿刺适形冷冻治疗肺癌的安全性、疗效和可行性.方法 研究对象为肺癌患者,纳入标准:(1)肺功能差、年龄大不能耐受开胸者;(2)周围型肺癌累及胸膜及胸壁肿瘤而无法彻底切除者;(3)肺癌通过临床综合治疗病灶缩小稳定,但不能消失者;(4)局限性肺癌,有手术切除适应证,但患者拒绝手术治疗者.排除标准:(1)双侧或单侧多发病灶患者;(2)肿块靠近纵隔大血管,预计穿刺途径不可避免地会伤及大血管者;(3)严重肺功能低下,肺最大通气容积<39%;(4)重度咳嗽,反复出现呼吸困难,不能配合治疗者;(5)肿瘤晚期、明显恶病质及出血倾向者.根据以上标准入选66例共76个病灶进行了冷冻消融,病灶最大径为1.5～16.0 cm,全部病灶按照肿瘤体积行17 G冷冻探针穿刺适形冷冻.肿瘤最大径<3.0 cm者采取双针"夹击"冷冻;肿瘤直径3.0～5.0 cm者采取多针穿刺适形冷冻;肿瘤最大径>5.0 cm者采取瘤内穿刺适形布针,针距<1.5 cm.患者术后随访6个月至2年.疗效评价采用CT增强扫描,观察病灶大小及强化情况.结果 本组18例肿瘤最大径<3.0 cm,术中CT复查显示冷冻范围超过病灶边缘1.0 cm以上,病灶局部密度减低,紧邻病灶周围可见窄带状透亮环绕,其外围肺组织密度增高,呈磨玻璃样环绕病灶形成靶征;术后1、3个月复查显示,病灶及邻近肺组织无强化;6个月后复查,扫描局部可见纤维条索影;7例随访时间达2年,其中5例肿瘤无复发和转移,1例术后1年发现纵隔淋巴结肿大,1例出现肿瘤骨转移.22例肿瘤最大径在3.0～5.0 cm之间,术后即刻CT复查显示,冷冻冰球覆盖全部病灶,病灶边缘的分叶和毛刺等恶性肿瘤征象消失,病灶体积轻度增大;术后1、3个月复查实性病灶逐渐缩小;9例患者随访达2年,其中4例肿瘤无复发,3例肿瘤稳定,2例出现其他部位转移.26例肿瘤最大径>5.0 cm,术中复查,冰球覆盖病灶体积70%～90%,周围肺组织无冷冻损伤改变.26例患者术后进行了放、化疗等综合治疗,随访6个月,9例病灶体积缩小,11例病灶稳定,6例病灶进展伴身体其他部位转移.本组患者术中3例出现咳血;术后26例痰中带血丝,19例出现气胸,其中5例行胸腔闭式引流,气体完全吸收,拔管时间平均为5 d.结论 CT引导监测,经皮穿刺适形冷冻治疗肺癌疗效肯定,是一种可行的微创方法.     

A new image navigation system for MR-guided cryosurgery.

PURPOSE: To evaluate the feasibility of Interactive Scan Control (ISC), a new MR image navigation system, during percutaneous puncture in cryosurgery. MATERIALS AND METHODS: With the ISC system in place, percutaneous MR-guided cryosurgery was performed in 26 cases, with the ISC system being used in 11 cases (five renal tumors, three uterine fibroids and three metastatic liver tumors). The ISC system comprised infrared cameras and an MR-compatible optical tracking tool that was directly connected to a cryoprobe. Tumor sizes ranged from 1.2 cm (metastatic liver tumor) to 9.0 cm (uterine fibroid), for a mean size of 3.9 cm. With ISC, one to three cryoprobes with a diameter of 2 mm or 3 mm were advanced into the tumors with the guidance of an MR fluoroscopic image. Two freeze-thaw cycles were used for cryosurgery. During the cryosurgery, the formation of iceballs was monitored on MR images. Follow-up dynamic CT or MRI as well as physical examinations were conducted after two weeks and six weeks. RESULTS: Placement of probes was successfully performed under the control of the ISC system. During cryosurgery, engulfment of the tumors by iceballs was carefully monitored by MRI. Necrosis of the cryoablated area was confirmed in all renal tumors by follow-up dynamic CT. The size regression of the uterine fibroids was observed through follow-up MRI. Two of the three cases of metastatic liver tumor were ablated completely. Additional therapy for a residual tumor was performed on one patient with a metastatic liver tumor. A small amount of pneumothorax was the only complication found in a patient with a metastatic liver tumor. CONCLUSION: MR-guided cryosurgery with this new navigation system was feasible with low morbidity and allowed for safe and accurate puncture with a cryoprobe.     

Intrahepatic tumor recurrence after partial hepatectomy: value of percutaneous radiofrequency ablation

PURPOSE: To determine the risks and benefits of percutaneous radiofrequency (RF) ablation of recurrent hepatic tumors in patients who have undergone hepatic resection. MATERIALS AND METHODS: Retrospective review of the institutional RF ablation database yielded 35 patients with recurrent hepatic tumor after hepatectomy. Sixty-one recurrent hepatic tumors (mean diameter +/- SD, 1.7 +/- 1.1 cm; range, 0.5-5.3 cm) were ablated percutaneously under sonographic guidance or combined guidance with sonographic and fluoroscopic computed tomography (CT). Follow-up CT, magnetic resonance imaging, or both were used for assessment of the primary and secondary therapeutic effectiveness rate and failure of RF ablation. Patients' survival status was determined by contacting the primary care physician or searching the Social Security Death Index. RESULTS: Complete ablation was accomplished in 54 of 61 hepatic tumors (primary therapeutic effectiveness rate, 88.5%). During a mean follow-up time of 18 months (range, 1-65 months), 14.8% of the tumors (n = 9) were incompletely ablated. Three of the nine incompletely ablated tumors were treated with a second RF ablation, all three of which failed (secondary therapeutic effectiveness rate, 0%). Distant intrahepatic tumor progression appeared in 23 of 35 patients (65.7%). One major complication (2.1%, one of 48 sessions) and eight minor complications (16.7%, eight of 48 sessions) were reported. The major complication was hepatic abscess formation. The overall survival rates for all patients at 1, 2, and 3 years were 76%, 68%, and 45%, respectively. For patients with metastases from colorectal cancer (n = 14), the overall survival rates were 72%, 60%, and 60% at 1, 2, and 3 years, respectively; and for patients with hepatocellular carcinoma (n = 8), the overall survival rates were 72%, 58%, and 44% at 1, 2, and 3 years, respectively. CONCLUSION: Percutaneous RF ablation offers a safe and effective treatment option for recurrent hepatic tumors after previous partial hepatectomy.     

Fine-needle percutaneous biopsy of renal masses with helical CT guidance

PURPOSE: To evaluate the feasibility, accuracy, and clinical role of fine-needle percutaneous biopsy of renal masses, with helical computed tomographic (CT) guidance. MATERIALS AND METHODS: In 63 patients (mean age, 62 years), 73 biopsies were performed. The median tumor size was 4.0 cm. Tumor biopsy was performed with an 18-gauge needle by using helical CT guidance in an outpatient setting. Two to four cores per tumor were obtained. RESULTS: Biopsy material was insufficient for analysis in 15 (21%) procedures. The median tumor size of failed or successful biopsies was 3.0 or 4.8 cm, respectively (P =.03). A benign lesion was found at eight biopsies. Two samples were suspicious for renal cell carcinoma (RCC). RCC was found in 38 biopsy samples. The remainder were transitional cell carcinoma, metastasis, lymphoma, or sarcoma. Twenty-six patients underwent nephrectomy. The accuracies of biopsy for histopathologic and Fuhrman nuclear grade evaluation were 89% and 78%, respectively. For tumors of 3.0 cm or smaller or larger than 3.0 cm, 37% (11 of 30) or 9% (four of 43) had failure of biopsy, respectively (P =.006). No substantial morbidity occurred. CONCLUSION: Fine-needle biopsy with helical CT guidance is accurate for the histopathologic evaluation of renal masses without morbidity. Indications are renal lesions that do not have the typical radiologic features of RCC, Bosniak category III or IV cystic lesions, and locally advanced or metastatic RCC.     

Local tumor recurrence following hepatic cryoablation: radiologic-histopathologic correlation in a rabbit model

PURPOSE: To use radiologic-histopathologic correlation in an animal model to distinguish normal postoperative findings from evidence of residual tumor after cryoablation of malignant hepatic tumors. MATERIALS AND METHODS: Hepatic cryoablation was performed in 12 rabbits with VX2 tumors and in two healthy rabbits. Nonenhanced and dynamic contrast material-enhanced computed tomography (CT) and magnetic resonance (MR) imaging and power and color Doppler flow ultrasonography (US) were performed 7-8 days after cryoablation. Histopathologic findings were correlated with imaging findings. RESULTS: Twenty tumors of 5-20 mm (mean, 10 mm) and seven areas of normal liver were treated with cryolesions of 11-21 mm (mean, 15 mm). All cryolesions exhibited arterial phase rim enhancement at CT and MR imaging, and 13 (57%) of 23 lesions demonstrated peripheral flow at US because of granulation tissue. There was macroscopic recurrence in 15 (75%) of 20 treated tumors; 14 (93%) appeared as peripheral nodularity with low-grade enhancement. Necrotic tissue did not enhance. Intact vessels extended up to 6 mm inside cryolesion margins and caused focal internal enhancement and Doppler flow. Areas of high signal intensity on T2-weighted MR images correlated with liquefaction necrosis, granulation tissue, and tumor. CONCLUSION: In this animal model, recurrent tumor typically appeared as focal nodules at the cryolesion periphery. Rim and central foci of enhancement, Doppler flow, and increased signal intensity on T2-weighted MR images can be normal findings after hepatic cryoablation.     

Radiofrequency Ablation for Viable Hepatocellular Carcinoma around Retained Iodized Oil after Transcatheter Arterial Chemoembolization: Usefulness of Biplane Fluoroscopy Plus Ultrasound Guidance

Objective

To assess the technical feasibility and local efficacy of biplane fluoroscopy plus US-guided percutaneous radiofrequency ablation (RFA) for viable hepatocellular carcinoma (HCC) around retained iodized oil after transcatheter arterial chemoembolization (TACE).

Materials and Methods

Our prospective study was approved by our institutional review board and informed consent was obtained from all participating patients. For patients with viable HCC around retained iodized oil after TACE, biplane fluoroscopy plus US-guided RFA was performed. We evaluated the rate of technical success and major complications on a post-RFA CT examination and local tumor progression with a follow-up CT.

Results

Among 40 consecutive patients, 19 were excluded due to one of the following reasons: poorly visible HCC on fluoroscopy (n = 13), high risk location (n = 2), RFA performed under monoplane fluoroscopy and US guidance (n = 2), and poorly identifiable new HCCs on US (n = 2). The remaining 21 patients with 21 viable HCCs were included. The size of total tumors ranged from 1.4 to 5.0 cm (mean: 3.2 cm) in the longest diameter. Technical success was achieved for all 21 HCCs, and major complications were observed in none of the patients. During the follow-up period (mean, 20.3 months; range, 6.5-29.9 months), local tumor progression was found in two patients (2/21, 9.5%). Distant intrahepatic metastasis developed in 76.2% (16/21) of patients.

Conclusion

When retained iodized oil around the tumor after TACE hampers the targeting of the viable tumor for RFA, biplane fluoroscopy plus US-guided RFA may be performed owing to its technical feasibility and effective treatment for viable HCCs.