Early indicators of treatment success after percutaneous radiofrequency of pulmonary tumors.

We retrospectively reviewed the imaging of patients after radiofrequency ablation (RFA) of lung metastases performed at our institution to assess the usefulness of ground glass opacification (GGO) margin for the prediction of complete tumor ablation. From January 2004 to March 2007, patients were identified where there was a postprocedure thin collimation scan to allow multiplanar reformatting, either immediately or at 24 h and at least 6 months of imaging follow-up. Thirty-six tumors in 22 patients were identified. The scans were assessed for the presence and width of GGO margin, and minimal and maximal dimensions were measured. A second reviewer, blinded to the outcome of the postprocedure assessment, reviewed the follow-up imaging for recurrence. The recurrence group had larger tumors (p = 0.045) and smaller mean minimal GGO margin width (p = 0.0001). Multivariate binary regression analysis confirmed that the minimal GGO margin was significantly (p < 0.005) associated with tumor recurrence. Receiver operator characteristic curve analysis suggests a cutoff of 4.5 mm for complete tumor ablation. There was substantial agreement (kappa = 0.759) between the site of absent GGO margin and the site of tumor recurrence. The point on the tumor surface where there is no GGO margin is likely to be the site of future recurrence. In our experience, a circumferential GGO margin of >5 mm is the minimal margion required to ensure complete tumor ablation.

Five-year survival in 309 patients with colorectal liver metastases treated with radiofrequency ablation.

There is little published long-term survival data for patients with colorectal liver metastases treated with radiofrequency ablation (RFA). We present a multivariate analysis of 5-year survival in 309 patients (198 male, aged 64 (24-92)) treated at 617 sessions. Our standard protocol used internally cooled electrodes introduced percutaneously under combined US and CT guidance/monitoring. The number and size of liver metastases, the presence and location of extrahepatic disease, primary resection, clinical, chemotherapy and follow-up data were recorded. Data analysis was performed using SPSS v.10. On multivariate analysis, significant survival factors were the presence of extrahepatic disease (p < 0.001) and liver tumour volume (p = 0.001). For 123 patients with five or less metastases of 5 cm or less maximum diameter and no extrahepatic disease median survival was 46 and 36 months from liver metastasis diagnosis and ablation, respectively; corresponding 3- and 5-year survival rates were 63%, 34% and 49%, 24%. Sixty-nine patients had three or less tumours of below 3.5 cm in diameter and their 5-year survival from ablation was 33%. There were 23/617(3.7%) local complications requiring intervention. Five-year survival of 24-33% post ablation in selected patients is superior to any published chemotherapy data and approaches the results of liver resection.

Quantitative secretin MRCP (MRCPQ): results in 215 patients with known or suspected pancreatic pathology.

Secretin magnetic resonance cholangiopancreatography quantification (MRCPQ) of pancreatic exocrine function correlates well with steatorrhoea and conventional, non-invasive function tests. We report MRCPQ results in a variety of pancreatic conditions. A total of 215 patients [107 male, mean age 46 years (14-78)] were studied. A multi-slice MRCP sequence was performed before and at 2-min intervals after 0.1 ml/kg IV secretin. Change in small intestinal water volume was plotted against time and the flow rate derived from the gradient. Patients were classified using clinical history, MRCP, MR imaging, computed tomography (CT) [150/215 (70%)] and endoscopic retrograde cholangiopancreatography (ERCP) [56/215 (26%)] findings but not MRCPQ results. Mean, standard deviation and 95% confidence intervals were calculated. The one way ANOVA and Student's t-test were used for statistical analysis. Seventy-six patients had chronic pancreatitis, 26 were post-surgical, 34 post-acute pancreatitis, six atrophic pancreatopathy, eight with obstruction, 15 divisum, ten sphincter of Oddi dysfunction, 26 normal and 14 miscellaneous. Significant differences were observed between normals (mean+/-SD; 7.4 +/- 2.9 ml/min) and severe chronic pancreatitis (5.3 +/- 2.4) (P = 0.018), pancreatic atrophy (3.8 +/- 3.1) (P = 0.013) or duct obstruction (5.3 +/- 2.4) (P = 0.047)) and between moderate (7.0 +/- 3.0) (P = 0.03) and severe chronic pancreatitis. MRCPQ can be used to quantify function across the spectrum of pancreatic disease and showed significant differences between several different pathologies.

Analysis of the factors associated with radiofrequency ablation-induced pneumothorax.

AIM: To define the characteristics most likely to result in radiofrequency ablation (RFA)-induced pneumothorax. METHODS AND MATERIALS: CT-guided RFA was performed in 79 tumours in 55 lungs in 37 patients, 16 were women, mean age 62 years (range 34-83). Three had primary lung cancer, 34 had metastases. The number, size, and location of tumours, electrode type, treatment parameters, length of electrode trajectory through aerated lung, background emphysema, prior interventions, and use of positive-pressure ventilation were analysed. The size, timing of any pneumothoraces, and intervention were recorded. RESULTS: Pneumothorax occurred in 21 of the 25 lungs treated (38%), 18 immediate and three delayed. Seventeen of the 21 (81%) occupied less than 30% of the hemithorax, whereas in four cases >31% was involved. Eight of the 55 (15%) pneumothoraces required aspiration. The length of the electrode trajectory through aerated lung in those who developed a pneumothorax was 5.4+/-4.7cm versus 1.9+/-2.7 in those who did not (p=0.001). The mean number of tumours ablated was higher in the pneumothorax group, 1.7+/-1 versus 1.3+/-0.6 (p=0.03), as was the number of electrode positions, 6+/-3.9 versus 3.6+/-2.2 (p=0.01). On multivariate analysis only the needle trajectory through aerated lung was significant (p=0.04). CONCLUSIONS: The number of tumours, electrode positions, and the anticipated electrode trajectory through aerated lung impacts on the likelihood of a pneumothorax. These considerations should be factored into patient selection, the choice of approach, and trajectory used in RFA.

Diagnosis of duct disruption and assessment of pancreatic leak with dynamic secretin-stimulated MR cholangiopancreatography.

OBJECTIVE: The management of pancreatic duct disruption is complex and depends on several factors including the cause, morphology, and degree of disruption. ERCP can show duct disruption in as many as 75% of patients but is invasive and cannot detect disruption beyond an obstruction. We studied the role of secretin MR cholangiopancreatography in patients with suspected pancreatic duct disruption. CONCLUSION: Secretin MR cholangiopancreatography is a safe, noninvasive test that can provide additional useful information about duct integrity and facilitate management.

Image guided tumour ablation.

Several different technologies have been employed for the local ablation of tissue by thermal techniques. At the present time the most widely favoured technique is radiofrequency ablation (RFA) but developments in other techniques, e.g. microwave may change this. In many countries RFA or percutaneous ethanol injection (PEI) are accepted therapies for patients with Childs Pugh Class A or B cirrhosis and early hepatocellular carcinoma (HCC). Results for RFA in large series of patients with liver metastases from colon cancer are very promising. Five-year survival rates of 26% from the time of first ablation and 30% from the diagnosis of liver metastases for patients with limited (<6, <5 cm) liver disease who are not surgical candidates compares well with post resection series where 5-year survival rates vary between 29% and 39% in operable candidates. Sufficient experience has now been gained in lung and renal ablation to show that these are minimally invasive techniques which can produce effective tumour destruction with a limited morbidity. More novel areas for ablation such as adrenal or pelvic recurrence are being explored.

Complications of percutaneous therapy.

Percutaneous tumour ablation is a minimally invasive, image guided procedure which attracts a low morbidity (2%-10%) and procedure-related deaths are exceptional. As such it can be offered to patients who could not withstand more invasive procedures such as surgical resection. Complications can be divided into systemic and local, those related to the anatomical area and those specific to the ablative technique or the particular tumour type. Most ablation experience has been gained using radiofrequency in the liver for metastases or hepatocellular carcinoma. Newer applications include ablation of inoperable lung primary or metastatic disease and renal cell carcinoma. The most common complications are haemorrhage, super-added infection or collateral damage. Tumour dissemination, whilst a theoretical risk, is very unusual.

CT mapping of the distribution of saline during radiofrequency ablation with perfusion electrodes.

PURPOSE: During radiofrequency (RF) ablation, adjunctive saline increases the size of the ablation zone and therefore electrodes that simultaneously deliver current and saline have been developed, but the addition of saline also results in an irregular ablation zone. Our aim was to study the distribution of saline during RF ablation. METHODS: Four patients were treated: 3 with liver metastases and 1 with hepatocellular carcinoma (HCC). Two different perfusion electrodes were used: a high-perfusion-rate, straight electrode (Berchtold, Germany) and a low-perfusion-rate, expandable electrode (RITA Medical Systems, USA). The saline perfusate was doped with non-ionic contrast medium to render it visible on CT and the electrical conductivity was measured. CT scans were obtained of each electrode position prior to ablation and repeated after ablation. Contrast-enhanced CT was performed 18-24 hr later to demonstrate the ablation zone. All treatments were carried out according to the manufacturer's recommended protocol. RESULTS: The addition of a small quantity of non-ionic contrast did not alter the electrical conductivity of the saline. Contrast-doped saline extravasated beyond the tumor in all 3 patients with metastases but was limited in the patient with HCC. In some areas where saline had extravasated there was reduced enhancement on contrast-enhanced CT consistent with tissue ablation. One patient treated with the high-perfusion-rate system sustained a jejunal perforation requiring surgery. CONCLUSION: Saline can extravasate beyond the tumor and with the high-perfusion-rate system this resulted in an undesirable extension of the ablation zone and a complication.

The use of radiofrequency in cancer.

Radiofrequency ablation (RFA) provides an effective technique for minimally invasive tissue destruction. An alternating current delivered via a needle electrode causes localised ionic agitation and frictional heating of the tissue around the needle. Image-guided, percutaneous ablation techniques have been developed in most parts of the body, but the most widely accepted applications are for the treatment of hepatocellular carcinoma (HCC) in early cirrhosis, limited but inoperable colorectal liver metastases, inoperable renal cell carcinoma and inoperable primary or secondary lung tumours. The procedures are well tolerated and the complication rates low. Patients with coexistent morbidity who are not suitable for surgery are often able to undergo RFA. Most treatments in the lung, kidney and for HCC are performed under conscious sedation with an overnight hospital stay or as a day-case. Larger more complicated ablations, for example, in hepatic metastases may require general anaesthesia. Limitations of RFA include the volume of tissue that can be ablated in a timely fashion, that is, most centres will treat 3-5 tumours up to 4-5 cms in diameter. Early series reporting technical success and complications are available for lung and renal ablation. Liver ablation is better established and 5-year survival figures are available from several centres. In patients with limited but inoperable colorectal metastases, the 5-year survival ranges from 26 to 30% and for HCC it is just under 50%. In summary, RFA provides the opportunity for localised tissue destruction of limited volumes of tumour; it can be offered to nonsurgical candidates and used in conjunction with systemic therapy.

Radiofrequency ablation of colorectal liver metastases.

BACKGROUND: Untreated patients with colorectal liver metastases rarely survive 3 years, and the 3-year survival rate for patients treated with chemotherapy is 3%. The best survival rates are for the small subgroup that has operable disease, i.e., 39% at 5 years. Radiofrequency ablation (RFA) offers a new opportunity to destroy liver metastases in patients who are not surgical candidates because of disease distribution or comorbidity. METHODS: Acceptance criteria were a maximum of four or five liver lesions with a maximum diameter of 4 or 5 cm and no evidence of active extrahepatic disease. Nearly all treatments were performed percutaneously using ultrasound, computed tomography, or magnetic resonance imaging (or some combination) for guidance and monitoring. RFA is a minimally invasive procedure that can be readily repeated. General anesthesia facilitates the procedure but is not essential. Multiple overlapping ablations are required to ensure optimal treatment in all but the smallest tumors. RESULTS: In our cohort of 167 patients with colorectal liver metastases, 73 fulfilled the optimal acceptance criteria (5 or fewer tumors that were

Radio-frequency ablation of colorectal liver metastases in 167 patients.

The objective of this paper is to report our results from a prospective study of 167 patients with colorectal liver metastases treated with radio-frequency ablation (RFA). Three hundred fifty-four treatments were performed in 167 patients, 99 males, mean age 57 years (34-87). The mean number of metastases was 4.1 (1-27). The mean maximum diameter was 3.9 cm (1-12). Fifty-one (31%) had stable/treated extra-hepatic disease. Treatments were performed under general anaesthesia using US and CT guidance and single or cluster water-cooled electrodes (Valleylab, Boulder, CO). All patients had been rejected for or had refused surgical resection. Eighty percent received chemotherapy. Survival data were stratified by tumour burden at the time of first RFA. The mean number of RFA treatments was 2.1 (1-7). During a mean follow-up of 17 months (0-89), 72 developed new liver metastases and 71 developed progressive extra-hepatic disease. There were 14/354 (4%) major local complications and 22/354 (6%) minor local complications. For patients with < or =5 metastases, maximum diameter < or =5 cm and no extra-hepatic disease, the 5-year survival from the time of diagnosis was 30% and from the time of first thermal ablation was 26%. Given that the 5-year survival for operable patients is a median of 32%, our 5-year survival of 30% is promising.

Radiofrequency ablation extends the scope of surgery in colorectal liver metastases.

AIMS: To assess outcome in patients treated by a multidisciplinary team, with a combination of liver resection and RF ablation. METHODS: Sixteen unselected patients (f=9; m=7) with colorectal liver metastases who were not suitable for surgery alone, were treated as follows: six had RF ablation at open laparotomy, three patients had synchronous ablation and resection while seven patients had RF ablation after liver resection. Standard liver resection techniques were used. RF was performed using internally cooled, single or cluster electrodes with a high power (200 W) generator. All patients were followed with regular contrast enhanced CT and survival noted. RESULTS: A total of 27 tumours with diameters 1.2-10 cm were treated. Two minor complications were recorded. 2/6 (33%) who had intraoperative RF had incomplete ablation due to large tumour size (6 and 10 cm respectively). Further RF ablation sessions were carried out successfully. 11/16 (69%) are alive at 2 years of whom 7 (44%) have no evidence of residual or recurrent liver disease. CONCLUSION: In our study, RF ablation extends the therapeutic envelope, is an effective local treatment of liver metastases and improves life expectancy.

Non-invasive quantification of pancreatic exocrine function using secretin-stimulated MRCP.

Our objective was to quantify water volume using magnetic resonance cholangiopancreatography (MRCP) sequences and apply this to secretin-stimulated studies with the aim of quantifying pancreatic exocrine function. A commercially available single-shot MRCP sequence was used in conjunction with a body phased-array coil and a 1.5-T MR system. Signal intensity was measured in samples of water, pancreatic, duodenal juice, and secretin-stimulated pancreatic juice. A water phantom was made and MR calculated volumes compared with known water volumes within the phantom. Changes in small intestinal volume in response to secretin were measured in a group of 11 patients with no evidence of pancreatic disease. Changes in water volume were plotted over time. The pancreatic duct diameter before and after secretin was noted and filling defects were sought. All patients also underwent an axial breath-hold T1-weighted gradient-echo sequence and the pancreatic parenchyma was evaluated for size and signal intensity. There was no difference in the signal intensity of the different juice samples. There was excellent correlation between known and calculated MRCP volumes (chi(2)=0.99). All patients demonstrated normal duct morphology on MRCP and normal pancreatic parenchyma on T1-weighted imaging. The mean flow rate in the patient population was 8.1+/-2.5 ml/s over a median of 7 min (range 5-9 min). The MRCP sequence can be used to measure water volume. Sequential MRCP measurements following secretin permitted calculation of volume change and flow rate. This should prove useful as an indicator of pancreatic exocrine function.

Comparison of B-mode and conventional colour/power Doppler ultrasound, contrast-enhanced Doppler ultrasound and spiral CT in the diagnosis of focal lesions of the liver: Results of a multicentre study.

AIM: In patients with lesions of the liver we compared diagnoses based on different methods of ultrasound as well as spiral CT with the final diagnosis reached at the time of the patient's discharge from hospital. METHOD: From records of a prospective multicentre study including 90 liver lesions investigated with B-mode baseline and conventional colour/power Doppler ultrasound, contrast-enhanced colour/power Doppler ultrasound and spiral-CT, we evaluated only those where diagnoses for all modalities were available, and where the diagnosis at discharge comprising all clinical, laboratory and imaging data as well as histologic proof was at least "highly probable". RESULTS: 60 lesions met the inclusion criteria. 20 lesions were ultimately diagnosed as benign, and 40 as malignant. With respect to the diagnosis of malignancy, sensitivity was 92.5 % (37/40) with B-mode and unenhanced conventional colour/power Doppler US ultrasound, 97.5 % (39/40) with contrast-enhanced colour/ power Doppler ultrasound, and 100 % with CT; the corresponding specificities were 65 % (13/20), 85 % (17/20) and 80 % (16/20). 4 of 7 false positive, and 2 of 3 false negative results in the unenhanced technique were diagnosed correctly with contrast-enhanced Doppler ultrasound. CONCLUSION: Compared to conventional ultrasound, contrast-enhanced Doppler ultrasound improved the diagnostic accuracy in 10 % of the cases. Its accuracy in our study was equal to that of CT.

Spiral CT pneumocolon: applications, status and limitations.

CT pneumocolon is a promising new technique in the diagnosis and management of colon pathology. CT pneumocolon can detect (sensitivity >95%) and stage (accuracy 79%) colorectal cancer and is very accurate in the differentiation of malignant from benign colonic pathologies. It has excellent detection rates for polyps >10 mm in diameter. Several studies using 3D virtual colonoscopy have already proven its high sensitivity and specificity in polyp detection making this technique robust as a screening tool. The combined results for virtual colonoscopy, from all centres, show a sensitivity of >85% in the detection of polyps 10 mm or greater in size, 70-80% for 5-9 mm polyps and an overall specificity of 90%. CT pneumocolon is a safe, non-invasive and cost-effective method for detecting colonic carcinomas and adenomas and correctly identifying which patients need further colonoscopy. The technique is quick, well tolerated and non-operator dependent. It can also image the proximal colon when distal stenoses prevent endoscopic and barium examination. CT pneumocolon is able to identify the features and complications of inflammatory bowel disease. Further research is warranted to fully assess its impact in terms of a screening tool, acceptability, availability and cost benefit.

Neo-adjuvant therapy improves resectability rates for colorectal liver metastases.

PURPOSE: Liver resection improves survival in selected patients with colorectal liver metastases. However, the majority of patients with colorectal liver metastases have inoperable disease at presentation. Neo-adjuvant therapy (systemic or regional chemotherapy and interstitial laser therapy) used singly or in combination may convert a selected group of patients with irresectable liver metastases into an operable state. PATIENTS AND METHODS: We report a series of patients with initially inoperable multiple colorectal liver metastases who became operable after neo-adjuvant therapy. Operability was defined as unilateral disease limited to the liver. Twelve patients (7 female, 5 male, median age 57 years, range 38-69 years) with multiple inoperable colorectal liver metastases (8 synchronous, 4 metachronous) were initially treated with systemic chemotherapy (n = 7), hepatic arterial chemotherapy (n = 2) and chemotherapy plus interstitial laser therapy (n = 3). RESULTS: In all cases, a significant response was achieved which enabled subsequent liver resection to be undertaken. There was only one postoperative complication (8%) and no peri-operative deaths. 3 patients were operated on within the last 12 months and are still alive. Of the remainder, 1 died within 1 year with recurrent disease. The remaining patients have a median survival of 2.5 years, range 1.39-4 years. CONCLUSIONS: These results are similar to those reported for patients undergoing resection for operable metastases without neo-adjuvant therapy. Aggressive multimodality treatment of colorectal liver metastases in specialised centres may improve the resectability rates and survival in a selected group of patients.

Survival after percutaneous, image-guided, thermal ablation of hepatic metastases from colorectal cancer.

PURPOSE: One-year, two-year, three-year, and four-year survival rates and median survival time for patients with inoperable liver metastases from colorectal cancer is 32, 10, and 3 percent and 7.4 to 11 months, respectively. Systemic chemotherapy produces a modest improvement to 48, 21, and 3 percent and 12 months, respectively. Regional chemotherapy produces a further improvement to 64, 25, and 5 percent and 15 to 17 months, respectively. For those with operable disease, hepatic resection survival rates are 90, 62, 48, and 40 percent, respectively, and survival time is 33 months. Thermal ablation is effective in producing necrosis in liver metastases. We report the impact on survival in 69 patients treated from 1993 to 1997, with follow-up to 1998. METHODS: Sixty-nine patients, 50 male, mean age 60 (range, 33-87) years were treated. Liver resection was not feasible because of disease extent in the liver, extrahepatic disease or concurrent medical conditions. The average number of liver metastases was 2.9 (range, 1-16), the mean maximal diameter was 3.9 (range, 1-8) cm, and the mean initial total liver tumor volume was 47 (range, 1-371) ml. Eighteen (26 percent) had undergone previous hepatic resection. Sixty-two of 67 (93 percent) received chemotherapy at some stage. Twenty (29 percent) had extrahepatic disease. RESULTS: One-year, two-year, three-year, and four-year survival rates and median survival time from liver metastasis diagnosis was 90, 60, 34, and 22 percent and 27 months, respectively. Forty of 69 (58 percent) developed new liver metastases, and 23 of 69 (33 percent) developed new extrahepatic disease. Of a subgroup of 24 patients with less than four metastases, <5 cm diameter, treated after January 1995, the median survival time was 33 months from first thermal ablation vs. 15 months for the remainder (P = 0.0004). Major morbidity occurred in 3.2 percent, minor morbidity occurred in 12 percent, and there was one periprocedural death. CONCLUSIONS: Thermal ablation therapy improves survival in patients with inoperable but limited liver metastases. This is an improvement on the natural history of the disease and published chemotherapy results. Recent and ongoing technical refinements, not reflected in these results, are expected to further improve survival.