MR-guided interstitial laser-induced thermotherapy of hepatic metastasis combined with arterial blood flow reduction: technique and first clinical results in an open MR system

The feasibility and safety of percutaneous laser-induced thermotherapy (LITT) of liver metastases in an open low-field magnetic resonance imaging (MRI) system combined with microsphere-modulated blood flow reduction were tested. Nd:YAG laser therapy with an internally cooled laser applicator was performed under local anesthesia on 20 patients with 34 liver metastases. To increase the effectiveness of LITT, degradable starch microspheres were injected into the proper hepatic artery through an MR-visible catheter initially inserted under fluoroscopy. Near real-time imaging was used for positioning the laser applicator. A T1-weighted gradient-echo breath-hold sequence was used for catheter localization and temperature monitoring. The volumes of the liver metastases and the thermonecroses were determined. MRI-guided LITT could be performed in all patients with no clinically relevant complications. Intraprocedural imaging underestimated the extent of thermonecrosis. In conclusion, percutaneous LITT of liver metastases after injection of starch microspheres is both technically feasible and safe in an open MRI system. J. Magn. Reson. Imaging 2001;13:31-36.     

MR-guided radiofrequency ablation in a 0.2-T open MR system: technical success and technique effectiveness in 100 liver tumors

PURPOSE: To evaluate the feasibility and technique effectiveness of magnetic resonance (MR)-guided radiofrequency (RF) ablation of hepatic malignancies. MATERIALS AND METHODS: In 64 patients, 100 primary (N = 19) or secondary (N = 81) liver tumors (mean diameter = 24.7 mm; range = 4-60 mm) were treated with 87 sessions of MR-guided RF ablation. The entire ablation procedure was carried out at an 0.2-T open MR system by using MR-compatible internally cooled electrodes. T2-weighted turbo spin echo sequences (TR/TE = 3500 msec/110 msec) were used to monitor thermally induced coagulation. Technique effectiveness was assessed four months after the last RF ablation by dynamic MR imaging at 1.5-T. RESULTS: MR-guided RF ablation procedures were technical successful in 85 of 87 (97.7%) assessed at the end of each session. Complete coagulation was intended in 99 of 100 tumors. Technique effectiveness was observed in 92 of 99 (92.9%) of these tumors. To achieve complete coagulation 82 of 92 (89.1%) tumors required a single session. T2-weighted sequences were accurate to monitor the extent of coagulation and were supportive to guide overlapping ablation. There were two of 87 (2.3%) major and seven of 87 (8.0%) minor complications. CONCLUSION: MR-guided RF ablation is a safe and effective therapy in the treatment of hepatic malignancies. MR imaging offers an accurate monitoring of thermally-induced coagulation, thus enabling complete tumor coagulation in a single session.     

Local tumor progression after radiofrequency ablation of colorectal liver metastases: evaluation of ablative margin and three-dimensional volumetric analysis

PURPOSE: Detection of local tumor progression (LTP) after radiofrequency (RF) ablation of colorectal cancer liver metastases may facilitate repeat intervention with potential benefits for patient survival. Ablative margins 1 month after RF ablation may predict LTP, and repeated three-dimensional (3D) volumetric analysis of coagulation volume after ablation may provide earlier detection of LTP versus conventional morphologic criteria. MATERIALS AND METHODS: Seven patients with LTP and four patients without LTP after a follow-up of at least 24 months were identified. Multidetector computed tomography (CT) was performed at 1 and 3 months after RF ablation and then at 3-month intervals until 24 months. Ablative margins were determined from preablation tumor diameter and the corresponding coagulation diameter 1 month after ablation. Postablation coagulation volume was measured from 81 follow-up multidetector CT images using a seeding-based semiautomatic 3D method. RESULTS: LTP was detected at a median of 9 months (range, 6-21 months) after RF ablation. A coagulation diameter smaller than the preoperative tumor diameter was associated with LTP. Increase in coagulation volume was found in six of seven patients at the time of diagnosis of LTP by conventional morphologic criteria. CONCLUSION: Three-dimensional volumetric analysis of postablation coagulation volume is feasible for detection of LTP after RF ablation of colorectal cancer liver metastases. No advantage in early detection of LTP was found for 3D volumetric analysis compared with conventional morphologic criteria in this preliminary study. These findings may reflect a type II error caused by the limited sample size.     

Aktueller Stand und Entwicklungen der Laserablation in der Tumortherapie

PURPOSE: The purpose of this paper is to present technical innovations and clinical results of percutaneous interventional laser ablation of tumors using new techniques. METHODS; Laser ablation was performed in 182 patients (liver tumors: 131, non hepatic tumors-bone, lung, others: 51) after interdisciplinary consensus was obtained. The procedure was done using a combination of imaging modalities (CT/MRI, CT/US) or only closed high field MRI (1.5 T). All patients received an MRI-scan immediately after laser ablation. RESULTS: In 90.9% of the patients with liver tumors, a complete ablation was achieved. Major events occurred in 5.4%. The technical success rate of laser ablation in non-hepatic tumors was high, clinical results differed depending on the treated organ. CONCLUSIONS: The treatment of tumors of the liver and other organs up to 5 cm by laser ablation was a safe procedure with a low rate of complications and side effects. Image guidance by MRI is advantageous for precise tumor visualization in all dimensions, therapy monitoring, and control of laser ablation results.     

Percutaneous radio-frequency ablation of liver metastases from breast cancer: initial experience in 24 patients.

PURPOSE: To evaluate the authors' initial experience in a consecutive series of 24 patients with breast cancer liver metastases treated with radio-frequency (RF) ablation. MATERIALS AND METHODS: Twenty-four consecutive patients with 64 metastases measuring 1.0--6.6 cm in diameter (mean, 1.9 cm) underwent ultrasonography-guided percutaneous RF ablation with 18-gauge, internally cooled electrodes. Treatment was performed with the patient under conscious sedation and analgesia or general anesthesia. A single lesion was treated in 16 patients, and multiple lesions were treated in eight patients. Follow-up with serial computed tomography ranged from 4 to 44 months (mean, 10 months; median, 19 months). RESULTS: Complete necrosis was achieved in 59 (92%) of 64 lesions. Among the 59 lesions, complete necrosis required a single treatment session in 58 lesions (92%) and two treatment sessions in one lesion (2%). In 14 (58%) of 24 patients, new metastases developed during follow-up. Ten (71%) of these 14 patients developed new liver metastases. Currently, 10 (63%) of 16 patients whose lesions were initially confined to the liver are free of disease. One patient died of progressive brain metastases. No major complications occurred. Two minor complications were observed. CONCLUSION: On the basis of preliminary study results, percutaneous RF ablation appears to be a simple, safe, and effective treatment for focal liver metastases in selected patients with breast cancer.     

Radiofrequency ablation: effect of surrounding tissue composition on coagulation necrosis in a canine tumor model

PURPOSE: To determine the effect of surrounding tissue type on coagulation necrosis from radiofrequency (RF) ablation in a homogeneous animal tumor model. MATERIALS AND METHODS: Thirty canine venereal sarcomas were implanted in three tissue sites (subcutaneous, kidney, and lung) in 13 mildly immunosuppressed dogs. Five of 25 tumors, which were 19 mm +/- 3 (mean +/- SD) in diameter, were allocated to each of five groups: (a) subcutaneous tumors, (b) kidney tumors, (c) lung tumors with blood flow, and (d) subcutaneous and (e) renal tumors without blood flow, which was achieved by sacrificing the animal to eliminate tumor perfusion. A sixth group comprised larger subcutaneous tumors (mean diameter, 46 mm +/- 4) that were also treated. RF ablation was performed with a 1-cm tip and 5 minutes of ablation at 90 degrees C +/- 1. Impedance, temperature, and resultant coagulation diameter were recorded and compared. Data were analyzed statistically, including one-way analysis of variance to determine the effect of tissue conductivity (ie, systemic impedance) on necrosis size and tissue temperatures. Linear regression analysis was used to compare changes in impedance between the control and experimental groups. RESULTS: Increasing linear correlation was observed between tumor coagulation diameter and overall baseline system impedance (R(2) = 0.65). RF ablation of lung tumors resulted in the greatest coagulation diameter (13.0 mm +/- 3.5) compared with that in the other groups (P <.01). The smallest coagulation diameter was observed in kidney tumors in the presence of blood flow (7.3 mm +/- 0.6) compared with that in the other groups (P <.01). Elimination of blood flow in kidney tumors increased coagulation diameter to 10.3 mm +/- 0.6 (P <.01). After RF ablation, coagulation diameter in the subcutaneous tumor groups was the same (mean, 9.8 mm +/- 1.0) (difference not significant), regardless of tumor size or presence of blood flow. CONCLUSION: The characteristics of tissue that surrounds tumor, including vascularity and electric conductivity, affect ablation outcome. Predominance of tissue-specific characteristics will likely result in site-specific differences in RF-induced coagulation necrosis.     

CO2 gas perfusion: improved efficiency and safety with sapphire-probe laser ablation of human artery.

CO2 gas has been proposed as a new perfusion medium for laser angioplasty. To compare CO2 gas with conventional saline perfusion, 146 fresh specimens of normal and atheromatous human artery were irradiated with a neodymium: yttrium-aluminum-garnet laser with a sapphire probe in flowing whole blood in an experimental circulation-occlusion model. The dimensions of the ablation crater and the extent of the surrounding tissue damage were measured microscopically. Significantly better ablation of atheromatous plaque was achieved with CO2 perfusion than with saline perfusion: mean ablation areas were 5.0 mm2 versus 2.8 mm2, respectively (P = .001, Student t test). In contrast, the ablation areas on normal vessel wall were identical (mean, 3.4 mm2) with the two perfusion media. Moreover, CO2 gas functioned as a negative contrast agent and facilitated direct monitoring of the laser recanalization procedure. On an experimental basis, CO2 gas perfusion seems to improve the efficiency and safety of laser ablation in human arteries.     

Overcoming the heat-sink phenomenon: successful radiofrequency thermal ablation of liver tumors in contact with blood vessels

PURPOSE: To evaluate the efficacy and safety of computed tomography (CT)-guided radiofrequency thermal ablation (RFA) of liver tumors (hepatocellular carcinoma and liver metastases) > 3 mm in diameter that were in contact with blood vessels. MATERIALS AND METHODS: During a 3-year period RFA was performed in 28 patients (age range, 36-83 years; male/female ratio, 17:11) with liver tumors (primary and metastatic) that were in contact with blood vessels > 3 mm in diameter. Tumor diameter ranged from 1.7 to 5.1 cm. To evaluate the immediate response, dual-phase dynamic CT images were obtained after intravenous contrast material administration. Imaging follow-up was at 1, 3, 6, and 12 months post-RFA, and every year thereafter. RESULTS: All of 28 patients were treated with a total of 36 sessions. In 22 (79%) of the patients, complete ablation of the tumor was achieved. The remaining 6 (21%) patients showed irregular peripheral enhancement and underwent a second session. At 1-year follow-up 2 of the tumors showed a recurrent lesion and a new ablation was performed. The local tumor progression rate at 1-year follow-up was 8.7% and disease-free survival was achieved in 82.1% of the patients. Complications occurred in 4 patients (14.3%); 2 patients presented with a small sub-capsular hematoma, and 2 patients had a partial liver infarction. CONCLUSION: RFA is a safe and effective method, even with high-risk tumors adjacent to large blood vessels, which can lead to good results with minimal complications and a low rate of tumor progression.     

CT引导下射频消融术在肝癌治疗中的临床应用

目的 探讨射频消融治疗肝癌的方法及临床应用.方法 收集2010-2011年的肝癌患者15例,均在我科CT引导下利用RITA射频消融机治疗.其中原发性肝癌10例,胃癌肝转移3例,结肠癌肝转移2例.结果 15例患者经射频消融治疗后症状减轻,肿瘤不同程度缩小或密度减低,甲胎蛋白及肿瘤标志物指标下降.结论 射频消融治疗具有操作简便、创伤小、疗程短、安全可靠、可多次治疗并有较好的疗效,是一项有效可行的治疗方法.     

Three-dimensional gradient-echo imaging for percutaneous MR-guided laser therapy of liver metastasis

PURPOSE: To evaluate the use of three-dimensional (3D) gradient-echo (GRE) magnetic resonance imaging (MRI) for percutaneous MR-guided catheter placement for laser therapy of liver metastases. MATERIALS AND METHODS: Thirty-four patients were included. A total of 122 MR-guided percutaneous punctures of 67 liver metastases were performed on a 1.5T scanner (Symphony and Sonata; Siemens, Erlangen, Germany) using a 5.5F microcatheter system and titanium needle (Monocath; MeoMedical, Augsburg, Germany). In 88 of 122 procedures, a 2D fast low-angle shot (FLASH) T1-weighted GRE breath-hold sequence was acquired in the axial plane and if necessary in a second plane. Sequences were acquired and reviewed using the panel in the control room. In 34 of 122 procedures a 3D FLASH T1-weighted fat-saturated GRE (volume-interpolated breath-hold examination (VIBE)) sequence was acquired in the axial plane only. Acquisition and 3D review were controlled under sterile conditions with a panel inside the examination room (Syngo; Siemens). RESULTS: The 3D FLASH sequence significantly decreased the mean number of acquisitions needed to place the microcatheter with the titanium needle in the metastasis compared to interventions with the 2D FLASH sequence (2.9 +/- 0.83 vs. 4.4 +/- 1.63). With 2D FLASH imaging, acquisition in a second plane was necessary in 78 instances (20% of acquired 2D sequences) to ensure adequate positioning of the device during the procedure. The artifact caused by the titanium needle was smaller with the 3D FLASH sequence. The conspicuity of liver metastases and morphology (liver edge and vessels) was acceptable with both sequences. The 3D FLASH sequence improved differentiation when two to four titanium needles were inserted, due to smaller susceptibility artifacts caused by the needles. CONCLUSION: 3D GRE imaging with the capability to perform multiplanar reconstruction (MPR) shortens the procedure by reducing the number of sequences needed. Improved visibility of the titanium needles allows more precise insertion of multiple needles into the metastasis.     

Radiofrequency ablation: Effect of pharmacologic modulation of hepatic and renal blood flow on coagulation diameter in a VX2 tumor model

PURPOSE: To determine whether pharmacologic agents can be used to modulate blood flow in hepatic and renal tumors sufficiently to alter the extent of radiofrequency (RF)-induced coagulation. MATERIALS AND METHODS: VX2 tumors (8-15 mm) were implanted in the liver (n = 25) or kidney (n = 8) of 33 New Zealand White rabbits. RF was applied to tumors for 6 minutes with use of conventional electrodes (125 mA +/- 35; 90 degrees C +/- 2 degrees C tip temperature). In the hepatic model, blood flow was modulated with use of halothane, epinephrine, or arsenic trioxide (2-6 mg/kg). Laser Doppler flowmetry was used to quantify changes in hepatic blood flow. Correlation of blood flow with induced coagulation diameter was performed. RF ablation was then performed in a renal model with and without arsenic trioxide. RESULTS: For liver tumors, halothane and arsenic trioxide reduced blood flow to 40.3% +/- 17.8% and 29% +/- 15% of normal, respectively, whereas epinephrine increased blood flow to 207.8% +/- 97.9%. Correlation of blood flow to coagulation diameter was demonstrated (R(2) = 0.40). Coagulation measured 7 mm +/- 1 with epinephrine, 10 mm +/- 1 with normal blood flow, 12 mm +/- 3 with halothane, and 13 mm +/- 3 with arsenic trioxide (P <.04 compared with controls). In the renal model, arsenic trioxide decreased blood flow (44% +/- 16%) and increased coagulation diameter (10.9 mm +/- 1) compared with controls (84% +/- 11% and 7.6 mm +/- 1; P <.01, both comparisons). CONCLUSIONS: RF-induced coagulation necrosis in rabbit hepatic and renal tumors is affected by tumor blood flow. Pharmacologic modulation of tumor blood flow may provide a noninvasive way to decrease blood flow during thermally mediated ablation therapy, potentially enabling the creation of larger zones of coagulation necrosis.     

Radiofrequency thermal ablation in canine femur: evaluation of coagulation necrosis reproducibility and MRI-histopathologic correlation

OBJECTIVE: Our purposes were to determine whether a single application of radiofrequency energy to normal bone can create coagulation necrosis reproducibly and to assess the accuracy of MRI at revealing the extent of radiofrequency-induced thermal bone injury. MATERIALS AND METHODS: Using a 200-W generator and a 17-gauge cooled-tip electrode, a total of 11 radiofrequency ablations were performed under fluoroscopic guidance in the distal femurs of seven dogs. Radiofrequency was applied in standard monopolar mode at 100 W for 10 min. During radiofrequency ablation, the changes in impedance and currents were recorded. MRI, including unenhanced T1- and T2-weighted images and contrast-enhanced fat-suppressed T1-weighted images, was performed to evaluate ablation regions. Six dogs were killed on day 4 after MRI and one dog on day 7. RESULTS: In all animals, radiofrequency ablation created a well-defined coagulation necrosis and no significant complications were noted. The mean long-axis diameter and the mean short-axis diameter of the coagulation zones produced were 45.9 +/- 5.5 mm and 17.7 +/- 2.7 mm, respectively. At gross examination, thermal ablation regions appeared as a central, light-brown area with a dark-brown peripheral hemorrhagic zone, which was surrounded by a pale-yellow rim. On MRI, the ablated areas showed multilayered zones with signal intensities that differed from normal marrow on unenhanced images and a perfusion defect on contrast-enhanced T1-weighted images. The maximum difference between lesion sizes on MR images, established by measuring macroscopic coagulation necrosis, was 3 mm. The correlation between the diameter of coagulation necrosis and lesion size at MRI was strong, with correlation coefficients ranging from 0.89 for unenhanced T1-weighted images and 0.97 for unenhanced T2-weighted images to 0.98 for contrast-enhanced T1-weighted images (p < 0.05). CONCLUSION: Radiofrequency ablation created well-defined coagulation necrosis in a reproducible manner, and MRI accurately determined the extent of the radiofrequency-induced thermal bone injury.     

Adrenal metastases: CT-guided and MR-thermometry-controlled laser-induced interstitial thermotherapy

The aim of the study was to evaluate the feasibility, safety and effectiveness of CT-guided and MR-thermometry-controlled laser-induced interstitial thermotherapy (LITT) in adrenal metastases. Nine patients (seven male, two female; average age 65.0 years; range 58.7–75.0 years) with nine unilateral adrenal metastases (mean diameter 4.3 cm) from primaries comprising colorectal carcinoma (n = 5), renal cell carcinoma (n = 1), oesophageal carcinoma (n = 1), carcinoid (n = 1), and hepatocellular carcinoma (n = 1) underwent CT-guided, MR-thermometry-controlled LITT using a 0.5 T MR unit. LITT was performed with an internally irrigated power laser application system with an Nd:YAG laser. A thermosensitive, fast low-angle shot 2D sequence was used for real-time monitoring. Follow-up studies were performed at 24 h and 3 months and, thereafter, at 6-month intervals (median 14 months). All patients tolerated the procedure well under local anaesthesia. No complications occurred. Average number of laser applicators per tumour: 1.9 (range 1–4); mean applied laser energy 33 kJ (range 15.3–94.6 kJ), mean diameter of the laser-induced coagulation necrosis 4.5 cm (range 2.5–7.5 cm). Complete ablation was achieved in seven lesions, verified by MR imaging; progression was detected in two lesions in the follow-up. The preliminary results suggest that CT-guided, MR-thermometry-controlled LITT is a safe, minimally invasive and promising procedure for treating adrenal metastases.     

Actual role of radiofrequency ablation of liver metastases

The liver is, second only to lymph nodes, the most common site for metastatic disease irrespective of the primary tumour. More than 50% of all patients with malignant diseases will develop liver metastases with a significant morbidity and mortality. Although the surgical resection leads to an improved survival in patients with colorectal metastases, only approximately 20% of patients are eligible for surgery. Thermal ablation and especially radiofrequency ablation emerge as an important additional therapy modality for the treatment of liver metastases. RF ablation shows a benefit in life expectancy and may lead in a selected patient group to cure. Percutaneous RF ablation appears safer (versus cryotherapy), easier (versus laser), and more effective (versus ethanol instillation and transarterial chemoembolisation) compared with other minimally invasive procedures. RF ablation can be performed by a percutaneous, laparoscopical or laparotomic approach, and may be potentially combined with chemotherapy and surgery. At present ideal candidates have tumours with a maximum diameter less than 3.5 cm. An untreatable primary tumour or a systemic disease represents contraindications for performing local therapies. Permanent technical improvements of thermal ablation devices and a better integration of thermal ablation in the overall patient care may lead to prognosis improvement in patients with liver metastases.     

Laser-induced interstitial thermotherapy of liver metastases in an interventional 0.5 Tesla MRI system: technique and first clinical experiences

Laser-induced interstitial thermotherapy (LITT) surveyed by magnetic resonance imaging (MRI) has been shown to be effective in various applications. The laser treatment of colorectal liver metastases usually requires a separate device (e.g., ultrasound or CT) to position the laser applicator. In this study, we used an interventional 0.5 T MRI system, allowing both the navigation to the target tissue and on-line thermometry. Laser irradiation was performed using a near-infrared laser source combined with a cooled laser light guide. We treated 20 patients exhibiting a total of 58 colorectal liver metastases. Clinically relevant complications did not occur. No residual tumor was observed after laser irradiation in all metastases with a diameter below 2 cm. Metastases with a mean diameter between 2 and 3 cm demonstrated total necrosis in 71%, while in larger tumors this proportion decreased to 46% (diameter, 3-4 cm) and 30% (diameter, >4 cm), respectively. We conclude that LITT, guided by the employed interventional MRI system, is feasible and safe. The results suggest a more aggressive treatment, especially for larger metastases. J. Magn. Reson. Imaging 2001;13:729-737.     

Influence of NaCl Concentrations on Coagulation,Temperature, and Electrical Conductivity Using a Perfusion Radiofrequency Ablation System: An Ex Vivo Experimental Study

Purpose To determine, by means of an ex vivo study, the effect of different NaCl concentrations on the extent of coagulation obtained during radiofrequency (RF) ablation performed using a digitally controlled perfusion device. Method Twenty-eight RF ablations were performed with 40 W for 10 min using continuous NaCl infusion in fresh excised bovine liver. For perfusion, NaCl concentrations ranging from 0 (demineralized water) to 25% were used. Temperature, the amount of energy, and the dimensions of thermal-induced white coagulation were assessed for each ablation. These parameters were compared using the nonparametric Mann-Whitney test. Correlations were calculated according to the Spearman test. Results RF ablation performed with 0.9% to 25% concentrations of NaCl produced a mean volume of coagulation of 30.7 ± 3.8 cm³, with a mean short-axis diameter of 3.6 ± 0.2 cm. The mean amount of energy was 21,895 ± 1,674 W and the mean temperature was 85.4 ± 12.8°C. Volume of coagulation, short-axis diameter, and amount of energy did not differ significantly among NaCl concentrations (p > 0.5). A correlation was found between the NaCl concentration and the short-axis diameter of coagulation (r = 0.64) and between the NaCl concentration and the mean temperature (r = 0.67), but not between the NaCl concentration and volume of coagulation. Conclusion In an ex vivo model, continuous perfusion with high NaCl concentrations does not significantly improve the volume of thermal-induced coagulation. This may be because the use of a low-power generator cannot sufficiently exploit the potential advantage of better tissue conductivity provided by NaCl perfusion.     

Thermische Ablation von Lebermetastasen: Aktueller Stand und Perspektiven

Purpose. To present thermal ablation of liver metastases via laser induced thermotherapy. Material and methods. Different technical procedures of thermal ablation and online monitoring are used, as there are the MR-guided laser induced thermotherapy (LITT) and the radiofrequency ablaton thermotherapy (RF). Results. In a prospective non randomized study 606 patients with liver metastases were treated via MR-guided laserinduced thermotherapy. Inclusion criteria were the exclusion of extrahepatic tumor spread and a number of metastases lower than 5 and a size lower than 50 mm in diameter. The local tumor control rate in the 3 month and 6 month control study was 98.3%, the complication rate 3,5% (clinically relevant: 1,2%). The mean survival rate was 40,9 months for all patients with liver metastases without statistically relevant differences for various primaries, like colorectal carcinoma, breast cancer and various other tumors. Results for radiofrequency are so far limited with incidence of a higher local tumor recurrence rate versus LITT. Conclusion. MR-guided LITT results in a high local tumor control rate with improved survival.     

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。     

Use of the triaxial microcatheter method in super-selective transcatheter arterial chemoembolisation for hepatocellular carcinoma

Objectives

Transcatheter arterial chemoembolisation (TACE) has been widely used for inoperable hepatocellular carcinoma (HCC). Super-selective TACE is preferable to non-selective therapy, because it maximises the impact of treatment on the tumour while minimising damage to tumour-free liver parenchyma. It is therefore important to advance the catheter tip as close as possible in the feeding artery. There is now a new microcatheter with a 1.9-Fr tip with no taper, which can be inserted into a 2.7-Fr microcatheter. In this study we describe the new technique of using the two microcatheters called the triaxial microcatheter method.

Methods

We evaluated 30 TACE procedures to investigate whether or not the catheter tip could be advanced closer to HCC with the triaxial microcatheter method than with previous TACE using a conventional microcatheter.

Results

With conventional microcatheters, the level of embolisation was a lobar artery in 4 cases, segmental in 8 cases, subsegmental in 15 cases and sub-subsegmental in only 1 case. TACE could not be performed in two cases. When using the triaxial microcatheter method the level of embolisation was subsegmental in 8 cases, including 2 in which the level was the same as that with a conventional microcatheter, sub-subsegmental in 13 cases and more distal in 7 cases. In the two cases in which TACE could not be performed with the conventional microcatheter, it could be performed sufficiently using the new method. As a whole, in 28 of the 30 procedures (93%) we could successfully advance a catheter tip closer than with the previous TACE.

Conclusion

The triaxial microcatheter method appears to be useful.Hepatocellular carcinoma (HCC) is the most common primary neoplasm of the liver [1]. The incidence of HCC is particularly high in South East Asia and sub-Saharan Africa, but there is a clear rise in the incidence in Western Europe and the United States [2].Transcatheter arterial chemoembolisation (TACE) has been widely used in cases of HCC during the past 15 years. Digital subtraction angiography and advanced catheter technology have enabled super-selective catheterisation of the arterial branches feeding the tumour, particularly microcatheters in which the appearance of the microcatheter has contributed largely to this. Selective TACE is preferable to non-selective therapy because a selective approach maximises the impact of treatment on the tumour while decreasing collateral damage to tumour-free liver parenchyma [3–5]. Therefore, it is necessary to advance the catheter tip to the tumour as close as possible in the feeding artery. However, sometimes this may be difficult owing to vessel tortuosity or shape of the bifurcation and may result in sagging of the microcatheter or distal catheter displacement beyond the desired vessel ostium.There is now a new microcatheter available that has a 1.9-Fr tip with no taper. It can be inserted into a 2.7-Fr microcatheter, which has a large inner diameter and is usually used when a better quality angiogram is desired. We hypothesised that by using a 1.9-Fr no-taper microcatheter and 2.7-Fr microcatheter it should be possible to advance the catheter closer to the HCC. We thought the 2.7-Fr microcatheter would give a more stable position for the advancement of the 1.9-Fr no-taper microcatheter into the feeding artery. In this article we describe this new technique as the triaxial microcatheter method.     

Radiofrequency ablation of 100 hepatic metastases with a mean follow-up of more than 1 year

OBJECTIVE: The objective of our study was to evaluate the efficacy and safety of radiofrequency ablation of hepatic metastases performed either percutaneously for treatment of hepatic metastases in patients deemed ineligible for surgery or intraoperatively during partial hepatectomy to destroy unresectable metastases. SUBJECTS AND METHODS: Sixty-eight patients with 121 hepatic metastases (<5 metastases per patient) that were mainly colorectal in origin underwent 76 sessions of radiofrequency ablation with cooled-needle electrodes under sonographic guidance. Twenty-one patients with 33 metastases of 5-20 mm in diameter (mean +/- SD,13 +/- 7 mm) underwent intraoperative radiofrequency ablation. Forty-seven patients with 88 metastases of 10 to 42 mm in diameter (mean +/- SD, 26 +/- 9 mm) were treated with percutaneous radiofrequency ablation. Procedure efficacy was evaluated with dynamic enhanced CT and MR imaging performed 2, 4, and 6 months after treatment and then every 3 months. RESULTS: Radiofrequency ablation allowed eradication of 91% of the 100 treated metastases that were followed up for 4-23 months (mean, 13.7 months). Tumor control was equivalent for percutaneous radiofrequency ablation (90%) and for intraoperative radiofrequency ablation (94%). Failure to achieve tumor control occurred mostly with the largest tumor nodules. One bilioperitoneum and two abscesses were the major complications encountered after treatment of 121 metastases with a follow-up of more than 2 months. CONCLUSION: Radiofrequency ablation appears to be a promising therapeutic modality capable of extending the possibilities of partial hepatectomy and of efficiently treating small metastases percutaneously.