Radiofrequency Ablation for Treating Liver Metastases from a Non-Colorectal Origin

Objective

We wanted to assess the safety and efficacy of performing radiofrequency ablation (RFA) in patients with non-colorectal liver metastases.

Materials and Methods

In this retrospective study, 25 patients with 40 hepatic metastases (M:F = 17:8; mean age, 57 years; tumor size, 0.5-5.0 cm) from a non-colorectal origin (stomach, biliary, breast, pancreas, kidney and skin) were treated with RFA. The RFA procedures were performed using either an internally cooled electrode or a clustered electrode under ultrasound or CT guidance. Contrast-enhanced CT scans were obtained immediately after RFA and follow-up CT scans were performed within three months after ablation and subsequently at least every six months. The intrahepatic disease-free interval was estimated and the overall survival from the time of the initial RFA was analyzed using the Kaplan-Meier method.

Results

No intraprocedural deaths occurred, but four major complications developed, including abscesses (n = 3) and pneumothorax (n = 1). Technical effectiveness was determined on the initial follow-up images. During the follow-up period (range, 5.9-68.6 months; median time, 18.8 months) for 37 tumors in 22 patients where technical effectiveness was achieved, 12 lesions (32%, 12 of 37) showed local tumor progression and new intrahepatic metastases occurred in 13 patients (59%, 13 of 22). The median intrahepatic disease-free interval was 10.1 months. The 1-year, 3-year and 5-year overall survival rates after RFA were 86%, 39% and 19%, respectively.

Conclusion

RFA showed intermediate therapeutic effectiveness for the treatment of non-colorectal origin liver metastases.     

螺旋CT对射频消融治疗肝脏恶性肿瘤的疗效评价

目的　探讨螺旋CT在肝脏恶性肿瘤射频消融治疗后随访过程中的价值。方法　对 3 6例超声引导下经皮穿刺射频消融治疗的肝脏恶性肿瘤患者 (2 9例原发性肝癌和 7例转移性肝癌 )定期进行螺旋CT双期增强扫描检查 ,观察射频消融的效果及肿瘤复发的情况。结果　肿瘤残留或原位复发的主要征象是消融区的边缘呈带状或结节样强化 ,或在随访CT复查中 ,肿瘤的体积不断增大。在射频消融治疗后的首次CT复查中 ,2 8例 (77.8% )肿瘤出现完全坏死。在随后的CT随访复查中 ,2例 (5.6% )出现肝内原位复发 ,4例 (11.1% )出现肝内异位复发。结论　对于合适的肝脏恶性肿瘤 ,射频消融是一种疗效确切的肿瘤局部治疗方法 ,在其疗效评价和长期随访过程中 ,螺旋CT双期增强扫描是有效的影像检查手段     

FDG positron emission tomography in the surveillance of hepatic tumors treated with radiofrequency ablation

PURPOSE: Radiofrequency thermal ablation (RFA) is an emerging technique in the treatment of focal hepatic tumors. Magnetic resonance imaging (MRI) and computed tomography (CT) are currently used to monitor hepatic tumors after RFA for residual disease and recurrence. Fluorodeoxyglucose (FDG) positron emission tomography (PET) is an excellent imaging method for the detection of liver metastases, but it has not been thoroughly evaluated as an alternative to anatomic imaging in the surveillance of liver tumors treated with RFA. The purpose of this investigation was to determine the role of FDG-PET imaging in the surveillance of liver tumors treated with RFA. METHODS: Thirteen patients with histories of malignant tumors of the liver treated with RFA and who had received post-treatment FDG-PET scans were assessed retrospectively. One patient had two post-RFA FDG-PET scans, eight patients had concurrent MRI scans, and six patients had concurrent CT scans. Imaging findings were compared with the results of clinical follow-up. RESULTS: There were either recurrent tumors at the ablation site (8 patients) or new metastases (3 patients) in 11 patients. FDG-PET identified all 11 cases and did not misidentify any cases. Of the seven patients with positive PET findings who received an MRI scan, three were also positive on MRI (42.9%); the other four cases were either negative or equivocal. Of the four patients with positive PET findings who received a CT scan, only two had positive CT scan findings (50%). All recurrences diagnosed by PET were confirmed on clinical follow-up. CONCLUSION: In this preliminary study, FDG-PET was superior to anatomic imaging in the surveillance of patients treated with RFA for malignant hepatic tumors.     

Radiofrequency Ablation of Renal Tumors: Four-Year Follow-Up Results in 47 Patients

Objective

To retrospectively evaluate the intermediate results of radiofrequency ablation (RFA) of small renal masses (SRMs).

Materials and Methods

Percutaneous or laparoscopic RFA was performed on 48 renal tumors in 47 patients. The follow-up studies included a physical examination, chest radiography, creatinine level, and contrast-enhanced CT or MRI. To confirm the pathologic criteria of complete ablation, 35 patients underwent a follow-up biopsy. Recurrence was defined as contrast enhancement on imaging studies after 3 months, lesion growth at subsequent imaging, or viable cancer cells on follow-up biopsy.

Results

Technical success was achieved in 43 (89.6%) of 48 renal tumors. The mean tumor size was 2.3 cm and the mean follow-up period was 49.6 months. Repeated RFA was necessary in 5 tumors due to incomplete ablation. The overall complication rate was 35.8%, of which 96.2% were mild complications. Serum creatinine levels at 12 months after RFA did not differ from those before RFA (1.28 vs. 1.36 mg/dL). Four patients were found to have recurrence at various follow-up intervals, and distant metastasis was not found in any cases.

Conclusion

RFA appears to be a useful treatment for selected patients with SRMs. Our 4-year follow-up results disclose an excellent therapeutic outcome with RFA, while achieving effective local tumor control.     

肺部恶性肿瘤射频消融治疗后CT影像学改变

目的:观察分析肺部恶性肿瘤射频消融治疗后CT影像学改变。方法:搜集因肺部恶性肿瘤行CT引导下射频消融治疗的患者226例(共计消融灶233个),分析评价治疗后病灶CT影像学改变。患者中原发性肺癌201例,肺转移癌25例。接受射频消融的病灶直径1.00～10.60cm,平均(4.36±2.45)cm。平均随访时间13.61个月(1～30个月)。结果:215例患者(95.13%)治疗后立即出现消融灶周围肺组织内毛玻璃样改变,多在1个月内吸收;191患者(84.51%)治疗后肿瘤立即出现增大,127例患者(56.19%)出现消融灶内多发小空泡形成。术后51例患者(22.57%)出现空洞,恶性胸水多发生在治疗3个月以后。121例患者(65.05%)在术后第一个月随访时胸部CT提示病灶有增大,46.15%和50.89%的患者在3个月及6个月复查时病灶缩小,之后这一比例开始降低,至12个月时,只有33.64%的患者病灶较上一次评估时缩小,到24个月时这一比例降低到4.35%。结论:病变周围的毛玻璃样改变、空洞形成、多发小空泡形成和胸膜改变是射频消融后最常见的CT改变。体积较大的病灶更可能出现空洞改变,射频消融术后1个月内病灶多出现增大表现,治疗后6个月是病灶缩小最明显的时期,6个月后出现的病灶较上一评估周期增大提示患者肿瘤进展。CT是射频术后疗效评估的有效手段之一。     

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.     

Radiofrequency Ablation of Intrahepatic Cholangiocarcinoma: Preliminary Experience

The purpose of this study was to evaluate the safety and efficacy of percutaneous ultrasound (US)-guided radiofrequency ablation (RFA) in patients with intrahepatic cholangiocarcinoma (ICCA) in a small, nonrandomized series. From February 2004 to July 2008, six patients (four men and two women; mean age 69.8 years [range 48 to 83]) with ICCA underwent percutaneous US-guided RFA. Preintervetional transarterial embolization was performed in two cases to decrease heat dispersion during RFA in order to increase the area of ablation. The efficacy of RFA was evaluated using contrast-enhanced dynamic computed tomography (CT) 1 month after treatment and then every 3 months thereafter. Nine RFA sessions were performed for six solid hepatic tumors in six patients. The duration of follow-up ranged from 13 to 21 months (mean 17.5). Posttreatment CT showed total necrosis in four of six tumors after one or two RFA sessions. Residual tumor was observed in two patients with larger tumors (5 and 5.8 cm in diameter). All patients tolerated the procedure, and there with no major complications. Only 1 patient developed post-RFA syndrome (pain, fever, malaise, and leukocytosis), which resolved with oral administration of acetaminophen. Percutaneous RFA is a safe and effective treatment for patients with hepatic tumors: It is ideally suited for those who are not eligible for surgery. Long-term follow-up data regarding local and systemic recurrence and survival are still needed.     

Comparison of FDG-PET, PET/CT and MRI for follow-up of colorectal liver metastases treated with radiofrequency ablation: initial results

PURPOSE: Morphologic imaging after radiofrequency ablation (RFA) of liver metastases is hampered by rim-like enhancement in the ablation margin, making the identification of local tumor progression (LTP) difficult. Follow-up with PET/CT is compared to follow-up with PET alone and MRI after RFA. METHODS AND MATERIALS: Sixteen patients showed 25 FDG-positive colorectal liver metastases in pre-interventional PET/CT. Post-interventional PET/CT was performed 24h after ablation and was repeated after 1, 3 and 6 months and then every 6 months. PET and PET/CT data were compared with MR data sets acquired within 14 days before or after these time points. Either histological proof by biopsy or resection, or a combination of contrast-enhanced CT at fixed time points and clinical data served as a reference. RESULTS: The 25 metastases showed a mean size of 20mm and were treated with 39 RFA sessions. Ten lesions which developed LTP received a second round of RFA; four lesions received three rounds of treatment. The mean follow-up time was 22 months. Seventy-two PET/CT and 57 MR examinations were performed for follow-up. The accuracy and sensitivity for tumor detection was 86% and 76% for PET alone, 91% and 83% for PET/CT and 92% and 75% for MRI, respectively. CONCLUSIONS: In comparison to PET alone, PET/CT was significantly better for detecting LTP after RFA. There were no significant differences between MRI and PET/CT. These preliminary results, however, need further verification.     

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.     

Preoperative RFA simulation for liver cancer using a CT virtual ultrasound system

We developed a computed tomography (CT) virtual ultrasound system (CVUS) as an imaging system to support treatment under percutaneous ultrasound (US) guidance. This prototype clinical system, produced in collaboration with Tokyo Medical University, uses display software developed by Toshiba Medical Systems. We examined the utility of this system by scheduling treatment plans preoperatively and simulating puncture and radiofrequency ablation (RFA) for liver cancer. The study enrolled 51 liver cancer patients with 66 nodules 0.8-8cm in diameter in which RFA was performed between June 2004 and December 2004. Virtual US and multiplanar reconstruction (MPR) images were constructed on the basis of DICOM CT data and puncture and ablation of liver cancer were simulated. The following were evaluated: (1) how to avoid complications and determine an appropriate puncture route by simulating puncture with C-mode MPR images; (2) determination of the three-dimensional location of the tumor for ablation, as well as the adjacent organs and vessels, by MPR rotation 360 degrees around the center of the tumor (center lock); and (3) how to determine the center and volume of ablation and avoid injuries to nearby organs and vessels by simulating ablation procedures. C -mode MPR images were effective for (1) determining and modifying the puncture route in 35 of 51 cases (69.6%) and (2) determining the spatial location of vessels and nearby organs in 50 of 51 cases (98.0%) by the center lock; and (3) simulating the ablation helped determine the center and volume of ablation by avoiding injuries to vessels and nearby organs in 45 or 51 cases (88.2%). Taken together, the CVUS allowed easy simulation of local treatment of liver cancer under US guidance using CT data alone and the preoperative simulation predicted an improvement in the safety of local therapy of liver cancer.     

Risk factors for recurrence of small hepatocellular carcinoma after long-term follow-up of percutaneous radiofrequency ablation

Radiofrequency ablation (RFA) as a local therapy for liver cancer is widely used. The study is to evaluate the therapeutic efficacy of RFA on hepatocellular carcinoma (HCC) and identify the risk factors for recurrence. Clinical records of 124 patients with 135 small HCC with percutaneous RFA as a first-line treatment modality were evaluated in Liver Cancer Institute, Zhongshan Hospital from October 2001 to December 2006. With a median follow-up period of 46 months after RFA therapy, the 1-, 2-, 3-, 4-, and 5-year cumulative survival rates and disease-free survival rates were 91, 70, 61, 48 and 40% and 64, 44, 31, 24 and 24%, respectively. The total recurrence and metastasis rates were 50 and 6.5%, respectively. Independent risk factors for recurrence after RFA included tumor with diameter more than 3 cm, located near the intrahepatic blood vessels, subcapsular locations and PT prolonged more than 3 s. Severe complications occurred in 2 cases (1.6%), including biliary tract hemorrhage and subphrenic effusion. RFA appears to be a safe and effective treatment for HCC. It will benefit the efficacy of RFA therapy if those risk factors are considered during the clinical practice.     

Radiofrequency ablation for the treatment of liver tumors in the caudate lobe

PURPOSE: To evaluate the effectiveness of radiofrequency (RF) ablation for liver tumors located in the caudate lobe. MATERIALS AND METHODS: Ten patients (46-79 years of age; median, 70 y), eight with hepatocellular carcinoma (HCC) and cirrhosis and two with colorectal metastases in the caudate lobe, were treated with 5.8% NaCl tissue-perfused monopolar (n=7) or bipolar (n=3) RF ablation. The median tumor diameter was 41 mm (range, 25-70 mm). Procedures were performed under ultrasound and computed tomography (CT) guidance in eight and two patients, respectively. One month later, the treatment response was assessed by CT. RESULTS: Transhepatic right intercostal and transomental anterior epigastric routes were used for tumor puncture in eight and two patients, respectively. The entire RF ablation treatment required one or two procedures (median, 1.5), including two to 15 electrode repositionings (median, 6). After RF ablation procedure, one patient experienced jaundice that resolved spontaneously. In one patient, CT follow-up showed asymptomatic segmental biliary duct dilations. Median total hospital stay was 3 days (range, 2-9 d). Complete ablation was achieved in nine of 10 tumors. In one patient, ethanol ablation was necessary to complete RF ablation treatment. After a median follow up of 9.5 months (range, 5-25 mo), three patients remained tumor-free and seven had tumor relapse: two local, four distant, and one mixed. Repeat RF ablation was successfully performed in four cases. CONCLUSION: RF ablation of liver tumors located in the caudate lobe is effective despite the deep location of tumors and the vicinity of major vessels.     

Kryoablation – wieder da?

CLINICAL ISSUE: Primary and secondary liver tumors often limit patient outcome and only a minority of patients are eligible for potential curative surgery. Minimally invasive treatments, such as radiofrequency ablation (RFA), microwave ablation (MWA) and cryoablation are alternative treatment options in a curative and palliative setting. One major limitation of RFA and MWA is the limited size of tumor ablation. Furthermore during the procedure the ablation size can only be roughly estimated using RFA and MWA. STANDARD TREATMENT: RFA is the standard modality of minimally invasive tumor therapy. In comparison cryoablation is rarely used despite its advantages. TREATMENT INNOVATIONS: Argon-helium-based cryoablation systems of the newest generation combine the advantage of small diameter applicators comparable with those of RFA and MWA systems with intrinsic advantages. ACHIEVEMENTS: Cryoablation is a minimally invasive treatment option with advantages, such as virtually unlimited ablation size, real-time visualization using computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound and intrinsic analgesic effects. On the other hand it is not very time-efficient in comparison to MWA. Especially in liver metastases RFA is the preferred treatment option. PRACTICAL RECOMMENDATIONS: Cryoablation is a fascinating treatment option in minimally invasive tumor treatment. It demonstrates good results in hepatocellular carcinoma within the Milan criteria and T1a renal cell carcinoma. Furthermore it is a well-established treatment modality for palliative pain management in bone tumors.     

Computed Tomographic-Guided Radiofrequency Ablation of Recurrent or Residual Hepatocellular Carcinomas around Retained Iodized Oil after Transarterial Chemoembolization

Objective

To assess the clinical efficacy, safety, and risk factors influencing local tumor progression, following CT-guided radiofrequency ablation (RFA) of recurrent or residual hepatocellular carcinoma (HCC), around iodized oil retention.

Materials and Methods

Sixty-four patients (M : F = 51 : 13, 65.0 ± 8.2 years old) with recurrent or residual HCC (75 index tumors, size = 14.0 ± 4.6 mm) had been treated by CT-guided RFA, using retained iodized oil as markers for targeting. The technical success, technique effectiveness rate and complications of RFA were then assessed. On pre-ablative and immediate follow-up CT after RFA, we evaluated the size of enhancing index tumors and iodized oil retention, presence of abutting vessels, completeness of ablation of iodized oil retention, and the presence of ablative margins greater than 5 mm. Also, the time interval between transarterial chemoembolization and RFA was assessed. The cumulative local tumor progression rate was calculated using the Kaplan-Meier method, and the Cox proportional hazards model was adopted, to clarify the independent factors affecting local tumor progression.

Results

The technical success and technique effectiveness rate was 100% and 98.7%, respectively. Major complications were observed in 5.6%. The cumulative rates of local tumor progression at 1 and 2 years were 17.5% and 37.5%, respectively. In multivariate analyses, partial ablation of the targeted iodized oil retention was the sole independent predictor of a higher local tumor progression rate.

Conclusion

CT-guided RFA of HCC around iodized oil retention was effective and safe. Local tumor progression can be minimized by complete ablation of not only index tumors, but targeted iodized oil deposits as well.     

Open radio-frequency thermal ablation of renal VX2 tumors in a rabbit model using a cooled-tip electrode: feasibility,safety, and effectiveness

The purpose of this study was to evaluate the feasibility, safety, and effectiveness of radio-frequency (RF) ablation using an internally cooled-tip electrode on renal VX2 tumors implanted in rabbits. Thirty-three rabbits with implanted renal VX2 tumors were divided into two groups: an RF ablation (RFA) group (n=27) and a control group (n=6). In the RFA group, RFA was performed on 27 implanted VX2 tumors using a cooled RF electrode and they were divided into three subgroups according to the follow-up period: acute (1–3 days, n=12); subacute (1–4 weeks, n=9); and chronic (2–7 months, n=6). Contrast-enhanced spiral CT was performed before the RFA and at the day, day 3, weeks 1, 2, 4, and months 2 and 7, after the RFA. The therapeutic efficacy was evaluated by the survival rate, CT, and pathologic findings. The RFA of renal tumors was technically successful in each instance. Complete tumor ablation was achieved in 22 of the 27 rabbits (81.5%) in the RFA group: 5 rabbits survived longer than 8 weeks without any evidence of viable tumor (18.5%) and 17 rabbits were found free of viable tumors when killed (63.0%). Five rabbits showed local tumor relapse and/or hematogenous lung metastasis after ablation (a recurrence rate of 18.5%). There were 11 (40.7%) complications related to the procedure. This experimental study demonstrates the feasibility of RFA therapy to treat renal VX2 tumors in rabbits, although RFA for central tumors carries some major potential complications, including renal arterial injury. Electronic Publication     

腹腔镜射频消融治疗原发性肝癌的研究

目的：评价腹腔镜射频消融（RFA）治疗原发性肝癌的可行性、安全性及疗效。方法：51例原发性肝癌在全麻下行腹腔镜RFA治疗,共72个瘤体,平均最大肿瘤直径（3．4±1．0）cm。合并肝硬化49例、慢性结石性胆囊炎5例,糖尿病4例,凝血功能障碍10例。结果：51例均顺利完成腹腔镜RFA治疗,12例行腹腔镜胆囊切除术。未出现严重并发症。肿瘤完全坏死率为95．8％。随访12～58个月（平均35个月）,6例发现肝内新病灶,11例射频治疗部位复发,再次采用经皮RFA治疗9例,12例死于肿瘤复发或肝功能衰竭。结论：腹腔镜RFA治疗原发性肝癌安全可行,治疗效果可靠,但应选择瘤体位于肝脏表面或临近胆囊而且不宜手术切除的病例进行治疗。     

TACE+RFA和TACE+MWA应用于早期原发性肝细胞癌的疗效差异

目的探讨肝动脉化疗栓塞联合射频消融术(TACE+RFA)和肝动脉化疗栓塞联合微波消融术(TACE+MWA)应用于早期原发性肝细胞癌(PHC)的疗效差异。方法选取我院接受TACE+RFA或TACE+MWA治疗的68例早期PHC患者资料,其中TACE+RFA组31例,TACE+MWA组37例。比较两组患者的病灶消融率、并发症发生率,并对患者的生存情况进行分析。结果TACE+RFA组和TACE+MWA组病灶完全反应(CR)率差异无统计学意义(P>0.05)。在肿瘤直径≤3cm患者中,TACE+RFA组和TACE+MWA组病灶CR率差异无统计学意义(P>0.05);而在肿瘤直径3~5cm患者中,TACE+MWA组病灶CR率高于TACE+RFA组,差异有统计学意义(P<0.05)。两组患者的并发症(发热、腹痛、恶心&呕吐及额外镇痛)发生率比较,差异无统计学意义(P>0.05)。随访6.0~45.7个月,中位随访时间26.6个月。全组患者1年、2年、3年累积生存率分别为92.3%、85.2%、47.9%。其中,TACE+RFA组患者的1年、2年、3年累积生存率分别为87.1%、80.1%、43.1%,TACE+MWA组为96.8%、89.6%、52.9%,两组生存率差异无统计学意义(Log rankχ^2=3.506,P=0.061)。在肿瘤直径≤3cm患者中,TACE+RFA组患者1年、2年、3年累积生存率分别为90.0%、90.0%、60.0%,TACE+MWA组为88.9%、74.1%、74.1%,两组生存率差异无统计学意义(Log rankχ^2=0.010,P=0.922)。在肿瘤直径3~5 cm患者中,TACE+RFA组患者1年、2年、3年累积生存率分别为85.7%、75.6%、36.3%,TACE+MWA组为100.0%、95.2%、50.8%,TACE+MWA组生存率高于TACE+RFA组(Log rankχ^2=4.485,P=0.034)。结论TACE+RFA和TACE+MWA应用于早期PHC均是安全、有效的。肿瘤直径≤3 cm时,两种疗法疗效相当,而肿瘤直径3~5cm时,TACE+MWA的病灶消融率和生存率优于TACE+RFA。     

Computed tomography appearances of hypervascular hepatic tumors after percutaneous radiofrequency ablation therapy

A retrospective review of the computed tomography (CT) findings of patients with hypervascular liver tumors (26 hepatocellular carcinomas and 2 metastases [1 periampullary carcinoma and 1 neuroendocrine tumor]) who underwent percutaneous ultrasound-guided radiofrequency ablation (RFA) was performed. CT images consisted of nonenhanced and dual-phase contrast-enhanced helical CT images performed on a multidetector CT scan. Findings indicative of adequate tumor ablation on multidetector CT scanwere complete nonenhancement of the treated tumor with or without faint, thin, peripheral rim enhancement. Ablated lesions that showed complete nonenhancement on initial and subsequent follow-up CT examinations either remained stable or became progressively smaller. Thick rim or nodular peripheral enhancement was indicative of tumor residual or recurrence.     

CT imaging findings of pulmonary neoplasms after treatment with radiofrequency ablation: results in 32 tumors

OBJECTIVE: The purpose of this study is to describe the CT appearance of thoracic neoplasms after treatment with radiofrequency ablation (RFA). MATERIALS AND METHODS: Thirty-two thoracic neoplasms in 26 patients had pulmonary RFA and imaging follow-up. Fourteen neoplasms were primary lung cancer and 18 were metastases. The mean pretreatment neoplasm size was 3.1 cm (range, 1.0-7.0 cm), and the average number of neoplasms treated per patient was 1.2 (range, 1-3). The mean follow-up was 10.1 months (range, 1-30 months). Imaging findings on CT were evaluated by three radiologists and documented by consensus. RESULTS: The most common finding immediately after treatment was peripheral ground-glass opacity surrounding the treated neoplasm, seen in 27 of 32 tumors (84%). This rapidly resolved in all but one patient by the end of the first month. Cavitation was seen in 10 of 32 tumors (31%) on follow-up CT and was most common in neoplasms in the inner two thirds of the lung and adjacent to a segmental bronchus. Sixty percent of the cavitations decreased in size on follow-up scans. Ten of 32 tumors (31%) that did not develop cavitation developed bubble lucencies on follow-up CT. Pleural thickening was found in 12 of 22 (55%) parenchymal neoplasms, and linear opacifications were seen between the treated lesion and adjacent pleura in 14 of 22 parenchymal tumors (64%). Pleural effusions were seen in four patients (15%). Fourteen of 22 tumors (64%) with follow-up imaging at 1 month enlarged from pretreatment CT scans. At 3 and 6 months after RFA, the majority remained stable in size. CONCLUSION: Peripheral ground-glass opacity, cavitation, bubble lucencies, and pleural changes are common findings on CT after RFA. Many treated neoplasms increase in size from baseline on 1- to 3-month follow-up CT scans and then remain stable thereafter. Enlargement of a treated tumor after 6 months is felt to represent local recurrence. Stability of a treated lesion beyond 6 months does not guarantee continued stability.     

Preliminary retrospective investigation of FDG-PET/CT timing in follow-up of ablated lung tumor

OBJECTIVE: The aim of this study was to clarify the most appropriate follow-up initiation time point for positron emission tomography (PET)/computed tomography (CT) following radio frequency ablation (RFA) of lung tumors, and the cutoff values of maximum standard uptake value (SUV(max)) to evaluate local tumor progression. METHODS: We enrolled 15 patients (8 men, median age 62 years) with 60 tumors, who were treated with RFA of lung tumors and underwent fluorodeoxyglucose (FDG)-PET/CT following RFA. Local tumor progression was assessed by periodic chest CT images prior to and following intravenous administration of a contrast medium. The SUV(max) of three periods, namely, 0-3 months, 3-6 months, and 6-9 months after RFA, was evaluated. The appropriate time point for follow-up initiation and the cutoff value of SUV(max) were determined using receiver-operating characteristic (ROC) analysis. RESULTS: The median follow-up period was 357 days. Of 60 tumors, 10 showed local progression. The area under the ROC curve (Az) for the 6-9 months (P = 0.044) was the largest and almost equal to that of the 3-6 months (P = 0.024). Az for the 0-3 months was the smallest and statistically insignificant (P = 0.705). The cutoff value of 1.5 of SUV(max) at 3-9 months after RFA showed 77.8% sensitivity and 85.7-90.5% specificity. CONCLUSIONS: The appropriate follow-up initiation time point is at least 3 months following RFA. Thus, SUV(max) is a useful and reliable predictive indicator.