|Year : 2015 | Volume
| Issue : 6 | Page : 64-68
Transpulmonary computed tomography-guided radiofrequency ablation of liver neoplasms abutting the diaphragm with multiple bipolar electrodes
Q Zhang, X Li, J Pan, Z Wang
Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
|Date of Web Publication||24-Dec-2015|
Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730
Source of Support: None, Conflict of Interest: None
Background: Neoplasm abutting the diaphragm is one kind of the special sites of liver neoplasms treated with radiofrequency ablation (RFA), the purpose of this study is to evaluate the feasibility and safety of computed tomography (CT)-guided RFA of liver neoplasms abutting the diaphragm with multiple bipolar electrodes sequentially passing through the lung parenchyma. Materials and Methods: 37 patients were treated with transpulmonary CT-guided RFA. Technical success rate, perioperative complications, and local tumor progression were investigated. Results: The number of electrode (s) sequentially passing through the lung parenchyma (NPLP) was 1 electrode in 20 patients, 2 electrodes in 14 cases, and 3 electrodes in 3 cases. Technical success rate was 100%. The most of the perioperative complications were self-limiting and mainly included pneumothorax (11 cases, 2 needed percutaneous drainage), hemorrhage of the electrode track in the lung parenchyma (6 cases), a small amount of hemoperitoneum in perihepatic space (8 cases) and discomfort of the right shoulder (7 cases). Local tumor progression occurred in 6 cases during the follow-up (3–12 months). Multivariate logistic regression analysis showed that the incidence of pneumothorax was not related to NPLP (P = 0.50), length of the electrode (s) in the lung parenchyma (P = 0.18), types of anesthesia (P = 0.10), and indwelling time of the electrode (s) in the lung parenchyma (P = 0.28). Conclusion: CT-guided RFA of liver neoplasms abutting the diaphragm with multiple bipolar electrodes sequentially passing through the lung parenchyma is a feasible and safe therapeutic option.
Keywords: Diaphragm, liver neoplasm, radiofrequency ablation
|How to cite this article:|
Zhang Q, Li X, Pan J, Wang Z. Transpulmonary computed tomography-guided radiofrequency ablation of liver neoplasms abutting the diaphragm with multiple bipolar electrodes. Indian J Cancer 2015;52, Suppl S2:64-8
|How to cite this URL:|
Zhang Q, Li X, Pan J, Wang Z. Transpulmonary computed tomography-guided radiofrequency ablation of liver neoplasms abutting the diaphragm with multiple bipolar electrodes. Indian J Cancer [serial online] 2015 [cited 2019 Aug 24];52, Suppl S2:64-8. Available from: http://www.indianjcancer.com/text.asp?2015/52/6/64/172516
| » Introduction|| |
Radiofrequency ablation (RFA) is one of the important methods of comprehensive treatment for liver neoplasms, but if the lesion locates in the liver dome, especially adjacent to the pericardium, it is very difficult to treat by routine RF methods. Ultrasound (US) and computed tomography (CT) are the most commonly used image-guided equipments. It is very difficult for US to demonstrate the lesions located in the liver dome because of air. To overcome this shortcoming, some special techniques including artificial pleural effusion and artificial ascites are adapted. However, these techniques also have their limitations. Artificial pleural effusion is not fit for a patient with poor respiratory function reserves, and artificial ascites usually do not work well for patients with a history of abdominal surgery because of the presence of adhesions. CT can clearly demonstrate the anatomic relationship between the lesion and the surrounding tissues, the method of transpulmonary CT-guide RFA of lesions in the liver dome was firstly reported by Shankar et al., then many investigators used the method of CT fluoroscopy-guided transpulmonary RFA to treat the lesions under the diaphragm.,, The operators always used one electrode passing through the lung parenchyma to treat the mass in the liver dome, and most of the electrode was umbrella-type. As umbrella-type electrode has a higher incidence of diaphragm injury than
the needle-type electrode,, we prefer to use the needle-type bipolar electrodes to treat lesions abutting the diaphragm. Sometimes it is necessary to treat the lesion with more than one bipolar electrodes, so 2 or 3 electrodes must pass though the lung sequentially. The purpose of the study is to explore the safety and feasibility of CT-guided RFA of liver neoplasms abutting the diaphragm with multiple bipolar electrodes sequentially passing through the lung parenchyma.
| » Materials and Methods|| |
Patient and tumor characteristics
This retrospective study was approved by our institutional review board; informed consent was obtained from all patients before the procedures. Between February 2013 and May 2014, 37 patients (31 males and 6 females; mean age 57.4 ± 9.5 years; range from 30 to 80 years) with liver neoplasms located in the liver dome were treated with the method of transpulmonary CT-guided RFA. Each of the 37 cases had a single lesion, with 29 cases of hepatocellular carcinoma, one cholangiocarcinoma, and 7 liver metastases (4 from colorectal carcinoma, 2 from ovarian cancer, and one from pancreatic neuroendocrine tumor). Child-Pugh class A in 31 cases and class B in 6 cases. 26 patients underwent transcatheter arterial chemoembolization (TACE) before RFA. RFA was performed for 27 cases under general anesthesia, and for the other 10 patients under local anesthesia. The mean maximal diameter of the lesions was 2.66 ± 1.51 cm (ranging from 0.91 to 6.67 cm). The mean length of the electrode in the lung parenchyma (LILP) was 10.50 ± 7.51 mm (ranging from 2.91 mm to 43.42 mm). If more than one electrodes sequentially passing through the lung parenchyma in one case, each length of the electrode in the lung tissue was added, the sum total as the length of the electrodes in the lung tissue of this case. Electrode indwelling time (IDT) within the lung parenchyma was defined as the interval from the moment of the first electrode punctured into the lung tissue to the end of the RFA. The mean IDT was 41.78 ± 22.69 min (ranging from 14 min to 102 min). Among the 37 cases, 1 electrode passed through the lung parenchyma in 20 patients, 2 electrodes sequentially passed through the lung tissue in 14 cases, and 3 electrodes sequentially passed through the lung tissue in 3 cases.
The RF generator was the system of Olympus Celon proSurge (Germany, Olympus Winter and Ibe GmbH), the electrode was bipolar with internal liquid circulation, the electrode diameter was 15G and the active length was 20 mm, 30 mm, or 40 mm. Compatible power control units system was CelonLab POWER with the maximum permitted RF power output 250W, compatible tube pumps system was CelonAquaflow III. CT scanner system was SIEMENS SOMATOM perspective 2012A, contrast agent was Iohexol 350. The CT scanning parameters were as follows: 110 kVp, 120 mA, and 5-mm intervals.
General anesthesia was carried out by anesthetist using the method of endotracheal intubation anesthesia; local anesthesia was performed by an interventional radiologist using 2% lidocaine. In patients with local anesthesia, 10 mg morphine was preoperatively intramuscular injected in 30 min, 5 mg morphine was intravenously administrated at the beginning of the procedure. Patients were placed in the supine position. Contrast-enhanced CT scan was performed if the patient was not treated with TACE before RFA [Figure 1]a. For patients treated with TACE before RFA, CT scan was performed and multiplanar reformation was done to show the position of the lesion [Figure 2]a.
|Figure 1: A 58-year-old male patient with liver neoplasm located in the segment VIII who developed pneumothorax after undergoing transpulmonary radiofrequency ablation with one bipolar electrode. (a) Preprocedural axial arterial phase computed tomography scan obtained at the level of hepatic dome showed ring-like enhancing mass at segment VIII of liver. he size of the mass was 1.05 cm × 1.38 cm. (b) Intraoperative computed tomography scan showed the electrode with working length of 20 mm passing through the lung parenchyma and was accurately inserted into the lesion. (c) Postprocedural axial arterial phase computed tomography scan showed oval-shaped ablation zone with low attenuation, the enhancing rim which along the periphery of the ablation zone appears to be a relatively concentric and symmetric area with smooth inner margins. (d) Postprocedure image demonstrated a small amount of pneumothorax in the right thorax. The track of the electrode demonst ated strip-shaped hemorrhage in the lung parenchyma|
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|Figure 2: A 57-year-old male patient with colorectal liver metastases located in the segment VIII, which was treated with radiofrequency ablation after transcatheter arterial chemoembolization. (a) Axial and coronal nonenhanced computed tomography images showed the mass abutting the diaphragm, in which accumulated lipiodol deposit was clearly seen. (b) Intraoperative computed tomography scan shows 2 electrodes passed through the lung tissue sequentially. (c) Nonenhanced postprocedure computed tomography scan demonstrates hypoattenuated ablated zone surrounding the lipiodol deposit|
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In cases with general anesthesia, the ventilator was temporarily stopped at the end of expiration then the puncture was done, CT scan was performed to show the position of the electrode. The ventilator was restarted after CT scan. Hence, repeat until the optimal position of the electrode was obtained [Figure 1]b and [Figure 2]b. In patients with local anesthesia, before the CT examinations, patients were instructed to hold their breath at the end of expiration and at the same degree for each CT scan, so the hepatic position could be maintained at the same level for each CT scan during RFA. After sterilized the skin, local anesthesia was performed with 5–15 ml of 2% lidocaine. The electrode was inserted along the path designed preoperatively. CT was
performed to verify the accurate location of the electrode. If more than one electrodes needed to apply, repeated the procedures mentioned above [Figure 2]b.
After confirming that the electrode(s) was (were) located within the tumor, the RF generator (CelonLab POWER) was started at the rated power which was determined by the active length and the numbers of the electrodes used, meanwhile the tube pumps (CelonAquaflow III) was started. If rated energy was achieved, CT scan was performed to show the changes of the ablated area [Figure 2]c. If necessary, the electrodes were adjusted and another cycle of treatment performed. The goal was to achieve complete ablation of
the visible tumor, and a 0.5–1 cm-wide ablation margin of the surrounding normal liver parenchyma. After the procedure, tract ablation was performed during electrode retraction to prevent bleeding or tract seeding. Contrast-enhanced three-phase CT scan was immediately performed to show the ablated zone and to find out if there were postoperative complications such as exudation, pneumothorax, and so on.
Chest X-ray examination was performed at 4 h after the procedure to show whether the size of the pneumothorax increased or whether there was delayed pneumothorax occurred.
Technical success was defined as complete eradication of tumor enhancement in the contrast-enhanced CT.
Follow-up computed tomography examination
Technical success was estimated with contrast-enhanced CT images acquired immediately after RFA. Contrast-enhanced three-phase CT or magnetic resonance images were obtained every 3 months after RFA, local tumor progression was defined as the appearance of nodular or eccentric enhancement around or within the ablated tumor.
Analysis was carried out using STATA version 12.0 (StataCorp, 4905 Lakeway Drive, College Station, Texas 77845, USA). Qualitative data were analyzed with Chi-square, quantitative data were analyzed with Rank-Sum test or Student's t-test, and multivariate logistic regression analysis were performed with P < 0.05 considered significant.
| » Results|| |
The lesions located in the liver dome were clearly demonstrated with contrast-enhanced CT scan [Figure 1]a. Lipiodol deposit may be demonstrated in the patients who underwent TACE before RFA [Figure 2]a. On postprocedure contrast-enhanced CT images, the ablation zone was showed as a nonenhanced area with low attenuation, surrounded by a uniform and symmetric enhancing ring with clearly visible border [Figure 1]c.
Pneumothorax occurred in 11 cases (11/37, 29.73%), and percutaneous drainage was required for 2 cases. 57 electrodes were applied to pass through the lung parenchyma, among them 1 electrode passed through the lung parenchyma in 20 patients, 2 electrodes were sequentially inserted the lung tissue in 14 cases,
and 3 electrodes in 3 cases. In these 3 subgroups, pneumothorax occurred in 6 cases, 4 cases, and 1 case, respectively, and the incidence rates were 30%, 28.75%, and 33.33%, respectively. Hemorrhage of the electrode track in the lung parenchyma occurred in 6 cases [Figure 1]d, there was no hemoptysis occurred in these 6 patients. A small amount of hemoperitoneum in perihepatic space occurred in 8 cases which did not need further treatment. Discomfort of the right shoulder occurred in 7 cases and disappeared in 3–7 days.
Local tumor progression occurred in 6 cases during the follow-up, among them 3 cases were treated with additional RFA, one case was treated with TACE, and the other 3 cases abandoned further treatment because of metastasis developed in other organs.
Statistic results were summarized in [Table 1].
|Table 1: Multivariate logistic regression analysis to show the relationship between different factors and the incidence of pneumothorax|
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| » Discussion|| |
Neoplasm locates in the liver dome is one kind of the special sites of liver neoplasms treated with RFA, the method of transpulmonary RFA of liver tumors has been proved as an acceptable way based on its feasibility, effectiveness, and safety. It is necessary to simultaneously puncture through the pleura, lung parenchyma, and the diaphragm when using this method, so its possible complications mainly contain pulmonary injury-related complications and diaphragm injury-related complications. The possible pulmonary injury-related complications mainly include pneumothorax and hemorrhage of the lung. The symptom of diaphragm irritation is the main complication of diaphragm injury. Some lesions need to sequentially apply 2 or 3 bipolar electrodes to puncture the lung parenchyma. In this group, 14 cases needed 2 electrodes, while 3 cases needed 3 electrodes to successively puncture the lung parenchyma. Pneumothorax is the most frequent and important complication relates to the puncture of lung. Results of this study showed that 2 electrodes did not increase the incidence rate of pneumothorax. Pulmonary hemorrhage was self-limiting, and there was no hemothorax or hemoptysis occurred. Technique success rate of this study was 100%, and the local progression rate was also within the range reported in literature related to the local progression rate after RFA of the special site of liver cancers (16.22% and 7.69–28.00%).,, The symptom of diaphragm irritation was also self-limiting, which mainly demonstrated ache of the right shoulder and disappeared in several days. Above all, results of this study show that it is safe and feasible to use more than one electrodes to sequentially puncture through the lung parenchyma when to use the method of transpulmonary CT-guided RFA of tumor locates in the liver dome.
There were no consistent results of the relationship between the incidence rate of pneumothorax and the RF electrode length in the lung parenchyma. Miura et al. applied CT fluoroscopy-guided transpulmonary RFA of liver cancers, they reported that the main risk factors for pneumothorax were increased the length of electrode in the lung tissue and multiple punctures in one session, the incidence rate of this group was up to 67.11% (51/76). On the contrary, Park et al. reported that there was no relationship between the occurrence of pneumothorax and the RF needle length in the aerated lung parenchyma. The incidence rate of pneumothorax in this study was 29.73% (11/37), multivariate logistic regression analysis showed that the number of the electrode (s) passing through the aerated lung tissue, LILP, types of anesthesia, and IDT had no significant influence on the occurrence of pneumothorax. In this study, the electrode length passing through the lung tissue was 10.50 ± 7.51 mm (2.91–43.42 mm), which is much shorter than that reported by Miura et al.
(mean 19 ± 12 mm, rage from 4 mm to 54 mm), the higher occurrence of pneumothorax of the latter (29.73% and 67.11%) may be related to its longer length of electrode passing through the lung parenchyma.
Some other alternative techniques for treating neoplasms located in the liver dome include artificial pneumothorax, artificial pleural effusion, artificial ascites, oblique approach under the guidance of CT-multiplanar reformation images (CT-MPR), and CT fluoroscopy technology.,,,,,,,, In the method of artificial pleural effusion, 5% glucose solution is infused into the right pleural cavity under local anesthesia, thus the lung and liver can be separated, and it is possible to obtain an image of the hepatic dome under the guiding of US because of the increased ultrasonic resolution. The complication of this method mainly includes cough, dyspnea, and oxygen desaturation during the procedure, so it is not fit for patients with poor lung function reserves. If the depth of the mass is more than 10 cm, it is also difficult to obtain accurate US images even with the aid of contrast-enhanced US. Hence, if the lesion locates in a deeper area of the liver, it is also not suitable using this technique to treat with RFA under the guidance of US.,
Similar to artificial pleural effusion, in the method of artificial ascites, 5% glucose solution is infused into the space between the diaphragm and the liver, this technique also has its limitations. First, if the patient has a history of surgical resection, peritoneal adhesion may be occurred, so the 5% glucose solution cannot be infused into the space. Second, if the tumor locates in the bare area of the liver or the lesion has invaded the diaphragm, it is also impossible to separate the tumor from the diaphragm. Third, after artificial ascites the liver may float on the ascites when insert the electrode the liver may occur shifting, so it is sometimes difficult to target the index tumor. Finally, the omentum may be interposed into the space between the diaphragm and liver; it may be an obstacle for successful induction of artificial ascites.
CT-guided RFA by caudal-cranial oblique insertion under the guiding of CT-MPR images may avoid puncturing of the costodiaphragmatic sinus and the aerated lung parenchyma, so the incidence of pneumothorax may be reduced. However, the path of this technique is much longer, it may be difficult to accurately control the orientation of the electrode, accompanied by much more times adjustment of the electrode in the liver, so the incidence of complications relating to puncture of the liver such as hemorrhage may be increased. CT fluoroscopy technology has the equipment advantages of CT and fluoroscopy, such as high resolution and the character of real-time. However, in this technology, the operator must be exposed to X-ray, this method also has its disadvantages.,
Local tumor progression rate after RFA of liver neoplasms locate in the special sites is 2.10%-21.88%, which is closely related to the sizes and location of the tumors, types of the electrodes used in the procedure, the special skills applied in the procedure, and experiences of the operators.,,, The treatments of this study were carried out by 3 experienced interventional radiologists using the technique of transpulmonary RFA, electrodes used were bipolar needle type with internal liquid circulation, technical success rate of this group is 100%, and the local progression rate is 16.22% (6/37).
There are two main advantages of transpulmonary CT-guide RFA of lesions in the liver dome. First, CT images have the character of high resolution, the location of the lesion and the relationship between the lesion and the adjacent organs can be clearly demonstrated. Especially, when the lesion closely abuts on the pericardium, with the aid of CT images the operator may make a safety plan to treat this lesion with RFA. Second, the electrode path of this technique is much shorter, so the electrodes may be more easily and accurately inserted into the lesion.
However, there are some limitations or relatively unique complications of this technique. First, the lung parenchyma has to be punctured and passed through, so if the patient suffers emphysema or interstitial pneumonia, the incidence of pneumothorax will be increased. If the patient has a clinical history of pulmonary hypertension, the risk of pulmonary hemorrhage will also be increased. Hence, the clinical history of the pulmonary and the pulmonary function must be fully evaluated before using this technique. Second, some other rare complication such as air embolism may occur, which may be fatal. To prevent the occurrence of this complication, we puncture the lung at the end of expiratory meanwhile temporarily stop the breathing, there was no air embolism occurred in this study. Third, diaphragmatic hernia may occur after RFA because of the injury to the diaphragm. If the active section of the electrode locates too closely to the diaphragm, the diaphragm may be suffered injury. Diaphragmatic hernia is also a rare complication, it usually develops in 6–9 months after the procedure and the number of this complication is much more reported in umbrella-type electrodes than in needle-type electrodes., To reduce the incidence of this complication, we make the active section of the electrode(s) at least 1 cm away from the diaphragm. There was no diaphragmatic hernia occurred in our study, but if the patient has the symptom of dyspnea or abdominal distension during the follow-up, CT or US should be performed to exclude the occurrence of this complication.
This study has its limitations. First, this is a retrospective study, and the number of patients in this study is small, especially the number of cases with 3 electrodes sequentially puncturing through the lung parenchyma. Second, time of the follow-up is not long enough, we should observe longer time to show the effectiveness of this technique.
Moreover, to reduce the incidence of diaphragmatic injury, we may combine the technique of artificial ascites and transpulmonary CT-guided RFA with more than one bipolar electrodes passing through the lung tissue to treat lesions too closely abutting the diaphragm, may be this is a promising method. In conclusion, it is feasible and safe to use more than one bipolar electrodes sequentially passing through the lung parenchyma under the guidance of CT to treat liver neoplasms located in the liver dome, which does not increase the risk of pneumothorax.
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[Figure 1], [Figure 2]