Usefulness of abdominal belt for restricting respiratory cardiac motion and improving image quality in myocardial perfusion PET.

BACKGROUND: The current study evaluated the usefulness of a belt technique for restricting respiratory motion of the heart and for improving image quality of 13N-ammonia myocardial PET/CT, and it assessed the tolerability of the belt technique in the clinical setting. METHODS: Myocardial 13N-ammonia PET/CT scanning was performed in 8 volunteers on Discovery PET/CT 690 with an optical respiratory motion tracking system. Emission scans were performed with and without an abdominal belt. The amplitude of left ventricular (LV) respiratory motion was measured on respiratory-gated PET images. The degree of erroneous decreases in regional myocardial uptake was visually assessed on ungated PET images using a 5-point scale (0 = normal, 1/2/3 = mild/moderate/severe decrease, 4 = defect). The tolerability of the belt technique was evaluated in 53 patients. RESULTS: All subjects tolerated the belt procedure. The amplitude of the LV respiratory motion decreased significantly with the belt (8.1 ± 7.1 vs 12.1 ± 6.1 mm, P = .0078). The belt significantly improved the image quality scores in the anterior (0.29 ± 0.81 vs 0.71 ± 1.04, P = .015) and inferior (0.33 ± 0.92 vs 1.04 ± 1.04, P < .0001) wall. No adverse events related to the belt technique were observed. CONCLUSIONS: The belt technique restricts LV respiratory motion and improves the image quality of myocardial PET/CT, and it is well tolerated by patients.

The Effect of Misregistration Between CT-Attenuation and PET-Emission Images in 13N-Ammonia Myocardial PET/CT.

UNLABELLED: In 2-dimensional cardiac PET/CT, misregistration between the PET and CT images due to respiratory and cardiac motion causes tracer uptake to appear substantially reduced. The resolution and quality of the images have been considerably improved by the use of 3-dimensional (3D) PET acquisitions. In the current study, we investigated the impact that misregistration between PET and CT images has on myocardial (13)N-ammonia uptake in images reconstructed with 3D ordered-subset expectation maximization combined with time-of-flight and point-spread-function modeling. METHODS: Eight healthy volunteers (7 men and 1 woman; mean age ± SD, 53 ± 19 y) underwent (13)N-ammonia cardiac PET/CT at rest. First, any misregistration between the PET and CT images was manually corrected to generate reference images. Then, the images were intentionally misregistered by shifting the PET images from the reference images by a degree of 1, 2, 3, 4, 5, 10, and 15 mm along both the x-axis (left) and the z-axis (cranial). For each degree of misregistration, the PET images were reconstructed using the CT-attenuation images. The left ventricular short-axis PET/CT images were divided into 4 segments: anterior wall, inferior wall, lateral wall, and septum. The erroneous decrease in myocardial uptake in basal, mid, and apical slices was visually graded using a 4-point scale (0 = none, 1 = mild, 2 = moderate, and 3 = severe). Wall-to-septum uptake ratios were evaluated for the anterior, inferior, and lateral walls in the basal, mid, and apical slices. RESULTS: A statistically significant reduction in myocardial (13)N-ammonia uptake in the anterior (P < 0.01) and lateral (P < 0.05) walls was observed when misregistration was 10 mm or more. The uptake ratios for the anterior, lateral, and inferior walls in the reference images were 1.00 ± 0.04, 0.96 ± 0.08, and 0.91 ± 0.03, respectively. The ratios for the anterior and lateral walls significantly decreased when misregistration exceeded 10 mm (anterior wall, 0.80 ± 0.06, P < 0.0001; lateral wall, 0.82 ± 0.07, P < 0.01), whereas the ratio for the inferior wall was relatively small at all 7 degrees of misregistration (0.86 ± 0.05 at 15-mm misregistration, P = 0.06). CONCLUSION: In PET/CT images reconstructed with 3D ordered-subset expectation maximization combined with time-of-flight and point-spread-function modeling, we found a statistically significant artifactual reduction in tracer uptake in heart regions overlapping lung when misregistration between PET and CT exceeded 10 mm.

Open surgery for abdominal aortic aneurysm in the era of endovascular repair: comparison with long term results of endovascular repair using zenith stentgraft.

OBJECTIVE: Our study focuses on the long term result of open surgery and endovascular abdominal aortic aneurysm repair (EVAR) using the Zenith stentgraft. PATIENTS AND METHODS: A total of 237 patients underwent elective abdominal aortic aneurysm (AAA) repair between April 1999 and December 2006. Nineteen patients underwent EVAR, whereas 218 patients underwent open surgery. The mean follow-up time for EVAR group was 73.8 ± 49 months (range; 25-150 months), and 69.7 ± 46 months (range; 1-156 months) for open surgery group. RESULTS: One open surgery patient (1/218, 0.46%) died of aspiration pneumonia, whereas all the EVAR patients survived the operation. Remote complications requiring reintervention occurred in 8 patients (8/174, 4.6%) in open surgery group. Six EVAR patients (6/19, 31.6%) developed late aneurysm expansion, among whom four patients (4/19, 21.1%) required reinterventions after 3 or more years postoperatively. The need for reintervention persisted even at 11 years after initial EVAR. There was no significant intergroup difference in late mortality. CONCLUSIONS: There was no statistically significant intergroup difference in early and long term mortality. Complications requiring reinterventions, however, were more frequent in EVAR than in open surgery, especially in the late period. Long term follow-up is mandatory for comparison of the clinical results between open surgery and EVAR.

Impact of 18F-FDG-PET/CT on treatment strategy in colorectal cancer lung metastasis before lung radiofrequency ablation.

OBJECTIVE: The aim of the study was to evaluate prospectively the clinical impact of 2-(F)-fluoro-2-deoxy-D-glucose (F-FDG) PET/computed tomography (CT) on the pretreatment assessment of patients with colorectal lung metastasis before radiofrequency (RF) ablation. METHODS: The institutional review board approved this prospective study. The eligibility criteria for lung RF ablation were the presence of five or fewer colorectal lung metastases with a maximum tumor size of 3 cm and absence of extrapulmonary lesions. Lung RF ablation candidates who underwent pretreatment PET/CT studies were included. The incidence of detection of unexpected recurrent lesions on PET/CT was evaluated, along with its impact on subsequent treatments. Factors linked with the incidence of unexpected recurrent lesions were evaluated using univariate and multivariate analyses. RESULTS: Between October 2008 and June 2011, 60 patients were enrolled. Among the unexpected abnormal F-FDG accumulations found in 13 patients (21.7%), presence of extrapulmonary lesions was proved in 12 patients (20.0%, 12/60), prompting treatment strategy changes. One false-positive case was found (1.7%, 1/60). The sensitivity, specificity, and accuracy in detecting unexpected lesions by PET/CT were, respectively, 100, 97.9, and 98.3%. Elevation of the serum carcinoembryonic antigen level (>6.0 ng/ml) was the only significant factor linked with unexpected lesions in both univariate (P=0.02) and multivariate analyses (P=0.02). CONCLUSION: A PET/CT study should be performed in patients with colorectal lung metastasis before selecting them for lung RF ablation, especially when the carcinoembryonic antigen level is elevated.

Factors influencing the outcome of image-guided percutaneous drainage of intra-abdominal abscess after gastrointestinal surgery.

PURPOSE: To improve the selection of patients for percutaneous abscess drainage (PAD) to treat postoperative intra-abdominal abscess after gastrointestinal surgery, we investigated the factors predictive of outcome. METHODS: Of 143 consecutive patients with symptomatic postoperative intra-abdominal abscess after a gastrointestinal tract resection, 104 who underwent image-guided PAD as the initial treatment were reviewed. We assessed the possible associations between successful PAD and patient-, abscess-, surgical-, and drainage-related variables, and investigated the success rates of PAD for patients with vs. those without the factors related to successful outcome. RESULTS: Based on monitoring for 1 year after PAD, the success rate of this procedure was 85.6% (89/104). Multivariate analysis revealed that the interval between surgery and the onset of abscess (p = 0.0234) and a single abscess (p = 0.0038) were independently associated with a successful outcome. Single late-onset abscess resolved completely within 10 weeks in 91.4% of these patients. CONCLUSIONS: Despite new strategies aimed at preventing surgical site infection, PAD remains an important factor in the postoperative management of gastrointestinal surgery in Japan. Initial recognition of the day of onset and the number of abscesses are important prognostic factors.

Detection of local tumor progression by (18)F-FDG PET/CT following lung radiofrequency ablation: PET versus CT.

OBJECTIVE: The objective of this study was to compare the diagnostic performance for detecting local tumor progression between FDG PET and CT in patients who received lung radiofrequency (RF) ablation for the treatment of malignant lung tumors. METHODS: A total of 469 FDG PET/CT studies were performed at 4 time points (3, 6, 9, 12 months) after lung RF ablation in 143 patients (87 male and 56 female patients) with 231 tumors. The SUVmax was calculated in treated tumors in each PET image. The percentage decrease (% decrease) in ablative zone size was evaluated in each CT image. The final response was judged based on follow-up findings and histology. Diagnostic performance of FDG PET and CT images was evaluated using receiver operating characteristic analysis. RESULTS: Local tumor progression was identified in 37 patients (25.9%, 37/143) having 47 tumors (20.4%, 47/231) during the median follow-up of 24 months (range, 8-75 months). The area under the receiver operating characteristic curve of PET was higher than that of CT at all 4 time points (0.71 vs 0.55 at 3 months, 0.82 vs 0.60 at 6 months, 0.84 vs 0.66 at 9 months, and 0.92 vs 0.68 at 12 months), and its diagnostic performance was significant at each time point (P = 0.0010 at 3 months and P < 0.001 at 6, 9, and 12 months). However, the area under the receiver operating characteristic curve of CT was significant at 9 months (P = 0.040) and 12 months (P = 0.032). CONCLUSIONS: FDG PET/CT is better able to assess local tumor progression at 3 and 6 months after lung RF ablation than CT alone.

Frequency of and risk factors for complications after liver radiofrequency ablation under CT fluoroscopic guidance in 1500 sessions: single-center experience.

OBJECTIVE: The purpose of this article is to retrospectively evaluate the frequency of and risk factors for complications after liver radiofrequency ablation (RFA). MATERIALS AND METHODS: This was a retrospective study of 656 patients (with 1755 liver tumors) who underwent 1500 CT fluoroscopy-guided liver RFA sessions. Of those patients, 501 had primary liver tumor and 155 had liver metastases. Mortality and treatment-related complications were documented. Complications were evaluated according to the Common Terminology Criteria for Adverse Events (version 4.0). Major complications were defined as grade 3 or higher adverse events. Factors affecting frequent complications with a frequency of 1% or more were detected using multivariate analysis. RESULTS: Two deaths (0.1% [2/1500]) occurred. One patient died of liver failure subsequent to hemorrhage, and the other died of liver failure. The major complication rate was 2.8% (42/1500). The most frequent major complication was hemorrhage (1.1% [16/1500]). The absence of arterial embolization before RFA (p < 0.01), low hemoglobin level (p < 0.04), and elevated serum creatinine level (p < 0.04) were identified as significant risk factors for major hemorrhage. The minor complication rate was 17.1% (257/1500). Pneumothorax (7.7% [116/1500]) was the most frequent minor complication, followed by hemorrhage (7.0% [105/1500]). A transthoracic approach (p < 0.01) and subphrenic tumor location (p < 0.01) were significant risk factors for pneumothorax, and the use of a cluster needle (p < 0.02) and multiple tumors (p < 0.01) were significant risk factors for minor hemorrhage. CONCLUSION: CT fluoroscopy-guided RFA is a safe procedure with an acceptably low rate of major complications for liver tumor treatment. Factors identified in this study will help to stratify high-risk patients.

Computed tomography fluoroscopy-guided radiofrequency ablation following intra-arterial iodized-oil injection for hepatocellular carcinomas invisible on ultrasonographic images.

BACKGROUND: We aimed to evaluate therapeutic outcomes of radiofrequency (RF) ablation following intra-arterial iodized-oil injection for hepatocellular carcinomas (HCCs) invisible on ultrasonographic (US) images. MATERIALS AND METHODS: Informed consent was waived for this retrospective study approved by our institutional review board. Sixty-seven consecutive patients with 150 HCCs (mean diameter 1.3 ± 0.6 cm; range 0.5-4.2 cm) received 90 RF sessions following intra-arterial iodized-oil injection. Each patient had at least one HCC invisible on US images. Computed tomography (CT) fluoroscopy-guided RF ablation was performed within 1 week after the injection of iodized oil from feeding arteries of each tumor. Technical success was defined as a planned electrode placement and completion of ablation protocol. Technical success, complications, changes in liver function, local tumor progression, and survival were evaluated. RESULTS: All HCCs became visible on CT fluoroscopy after iodized-oil injection, and RF ablation was technically successful in all sessions (technical success rate, 100%, 90/90). Major complications occurred in 6 RF sessions (6.7%, 6/90), including hemorrhage (2.2%, 2/90), portal thrombosis (2.2%, 2/90), and pneumothorax (2.2%, 2/90). No significant deterioration in Child-Pugh score was found. The mean follow-up period was 23.2 ± 18.0 months. The cumulative local tumor progression rates and overall survival rates were, respectively, 3.9 and 82.7% at 1 year, 5.3 and 45.3% at 3 years, and 5.3 and 26.4% at 5 years. CONCLUSION: CT fluoroscopy-guided RF ablation following intra-arterial iodized-oil injection is a feasible, safe, and useful therapeutic option for HCCs invisible on US images.

Clinical utility of transarterial infusion chemotherapy using cisplatin-lipiodol emulsion for unresectable hepatocellular carcinoma.

BACKGROUND: We evaluated the clinical efficacy of transarterial infusion chemotherapy using a cisplatin-lipiodol emulsion for unresectable hepatocellular carcinoma (HCC). PATIENTS AND METHODS: Fifty-seven patients with advanced HCC, with no indications for surgical resection or local ablative therapy, such as percutaneous ethanol injection and radiofrequency ablation, were enrolled in this retrospective study. RESULTS: Twelve patients were treated with cisplatin-alone at a dose of 65 mg/m(2) by infusion into the artery. Forty-two patients were treated with the same dose of cisplatin suspended in 1-10 ml of lipiodol (C/LPD). Cumulative survival rates in the cisplatin-treated group were 46.2% at one year, and 18.5% at two years, whereas these in the C/LPD group were 81.6% and 44.4%, respectively, with a significant difference between the two groups (p<0.01). In the cisplatin-treated group (n=13), no (0%) patients had a complete response (CR), two (15%) a partial response (PR), three (23%) no change (NC), and eight (62%) progressive disease (PD). In the C/LPD group (n=44), four (9%) patients had CR, 16 (35%) PR, 12 (26%) NC, and 12 (26%) PD. CR and PR were seen in 15% of the cisplatin-treated group and in 44% of the C/LPD group. C/LPD was significantly more effective than cisplatin-alone (p=0.039). Some patients showed tumor response to C/LPD after intra-arterial infusion of low-dose 5-fluorouracil. CONCLUSION: C/LPD produced superior effects compared to cisplatin-alone for unresectable HCC, causing no major side-effects, and increasing the survival rate.

Radiofrequency ablation for colorectal liver metastases: prognostic factors in non-surgical candidates.

PURPOSE: To determine prognostic factors in patients with colorectal liver metastases who were not surgical candidates and received liver radiofrequency (RF) ablation. MATERIALS AND METHODS: RF ablation was done for 141 colorectal liver metastases in 84 patients. There were 63 (75.0 %, 63/84) males and 21 (25.0 %, 21/84) females, with a mean age of 64.6 ± 10.3. The mean maximum tumor diameter was 2.3 ± 1.4 cm (range 0.5-9.0 cm). Extrahepatic metastases were associated at the time of liver RF ablation in 23 patients (27.4 %, 23/84), and 12 (14.3 %, 12/84) had lung metastases considered controllable by planned lung RF ablation. Prognostic factors were evaluated by univariate and multivariate analyses. RESULTS: There was no procedure-related mortality. The 1-, 3-, and 5-year overall survival rates were 90.6 % (95 %CI, 83.9-97.2 %), 44.9 % (95 %CI, 31.8-57.9 %), and 20.8 % (95 %CI, 7.3-34.3 %), respectively, with a median survival of 34.9 months. The univariate analysis showed that tumor diameter larger than 3 cm, tumor multiplicity, uncontrollable extrahepatic disease, and previous chemotherapy history were significantly worse prognostic factors. The former three factors remained significant for worse prognosis in the multivariate Cox model. Extrahepatic disease was not a prognostic factor when it could be controlled. CONCLUSION: Tumor size and number, and uncontrollable extrahepatic metastases were significant prognostic factors.

Ablative zone size created by radiofrequency ablation with and without chemoembolization in small hepatocellular carcinomas.

PURPOSE: We retrospectively evaluated whether combined use of chemoembolization expands ablative zone sizes created by radiofrequency (RF) ablation in patients with small hepatocellular carcinomas (HCCs). MATERIALS AND METHODS: Fifty-seven patients treated with single RF ablation for solitary HCC measuring ≤2 cm were assessed. RF ablation alone was done in nine patients and in 48 patients following chemoembolization, with an interval of 0 days in 6, 1-14 days in 27, 15-28 days in 6, and ≥4 weeks in 9. Ablative zone sizes, disappearance of tumor enhancement, and creation of sufficient ablative margins (>5 mm) were evaluated on contrast-enhanced computed tomography (CT) images. RESULTS: Both mean long-axis (4.2-4.7 vs. 3.6 ± 0.4 cm, p < 0.04) and short-axis (3.3-3.8 vs. 2.3 ± 0.5 cm, p < 0.03) diameters were expanded significantly when RF ablation was done until 4 weeks after chemoembolization than with RF ablation alone. Tumor enhancement disappeared in all patients. Frequency of achieving sufficient ablative margins was significantly higher when RF ablation was done until 4 weeks after chemoembolization than with RF ablation alone (74.0-83.3 vs. 22.2 %, p < 0.05). CONCLUSION: Ablative zones created by RF ablation with chemoembolization become larger than RF ablation alone, leading to secure ablative margins.

Relation between FDG uptake and apparent diffusion coefficients in glioma and malignant lymphoma.

OBJECTIVE: This study evaluates the relation between 2-deoxy-2-[18F]fluoro-D: -glucose (FDG) uptake using positron emission tomography/CT and the apparent diffusion coefficient (ADC) in patients with glioma and malignant lymphoma. METHODS: For 36 patients (30 with glioma and 6 with malignant lymphoma), the standardized uptake value (SUV) ratio was calculated to assess the FDG uptake. Pearson's correlation analysis was used to assess the relation between the SUV ratio and the ADC value: those of low-grade glioma and high-grade glioma were compared, as were those of glioblastoma and malignant lymphoma. RESULTS: Inverse correlation between the SUV ratio and the minimum ADC was found for all cases (P < 0.0001, r = 0.68) and for glioma cases (P < 0.0001, r = 0.67). High-grade gliomas showed a significantly higher SUV ratio than low-grade gliomas did (P < 0.0001); they also showed significantly lower minimum ADC than low-grade gliomas did (P < 0.001). Cut-off values used for the SUV ratio of 0.9 and for the minimum ADC of 0.99 × 10(-3 )mm(2)/s were used to differentiate high-grade from low-grade gliomas, with high accuracy. Malignant lymphoma showed a significantly higher SUV ratio than glioblastoma (P < 0.0001). No significant difference in the ADC value was found between glioblastoma and malignant lymphoma (the minimum ADC: P = 0.13, the mean ADC: P = 0.084, respectively). CONCLUSIONS: An inverse correlation was found between the SUV ratio and the minimum ADC in glioma and malignant lymphoma. The SUV ratio and the minimum ADC are useful to evaluate the grading of gliomas. The SUV ratio might be more useful for differentiating malignant lymphoma from glioblastoma than the ADC value is.

Incidence and cause of hypertension during adrenal radiofrequency ablation.

PURPOSE: To evaluate the incidence and cause of hypertension prospectively during adrenal radiofrequency ablation (RFA). METHODS: For this study, approved by our institutional review board, written informed consent was obtained from all patients. Patients who received RFA for adrenal tumors (adrenal ablation) and other abdominal tumors (nonadrenal ablation) were included in this prospective study. Blood pressure was monitored during RFA. Serum adrenal hormone levels including epinephrine, norepinephrine, dopamine, and cortisol levels were measured before and during RFA. The respective incidences of procedural hypertension (systolic blood pressure >200 mmHg) of the two patient groups were compared. Factors correlating with procedural systolic blood pressure were evaluated by regression analysis. RESULTS: Nine patients underwent adrenal RFA and another 9 patients liver (n = 5) and renal (n = 4) RFA. Asymptomatic procedural hypertension that returned to the baseline by injecting calcium blocker was found in 7 (38.9%) of 18 patients. The incidence of procedural hypertension was significantly higher in the adrenal ablation group (66.7%, 6/9) than in the nonadrenal ablation group (11.1%, 1/9, P < 0.0498). Procedural systolic blood pressure was significantly correlated with serum epinephrine (R (2) = 0.68, P < 0.0001) and norepinephrine (R (2) = 0.72, P < 0.0001) levels during RFA. The other adrenal hormones did not show correlation with procedural systolic blood pressure. CONCLUSION: Hypertension occurs frequently during adrenal RFA because of the release of catecholamine.

Lung radiofrequency ablation for the treatment of unresectable recurrent non-small-cell lung cancer after surgical intervention.

PURPOSE: A retrospective evaluation was done of clinical utility of lung radiofrequency (RF) ablation in recurrent non-small-cell lung cancer (NSCLC) after surgical intervention. METHODS: During May 2003 to October 2010, 44 consecutive patients (26 male and 18 female) received curative lung RF ablation for 51 recurrent NSCLC (mean diameter 1.7±0.9 cm, range 0.6 to 4.0) after surgical intervention. Safety, tumor progression rate, overall survival, and recurrence-free survival were evaluated. Prognostic factors were evaluated in multivariate analysis. RESULTS: A total of 55 lung RF sessions were performed. Pneumothorax requiring pluerosclerosis (n=2) and surgical suture (n=1) were the only grade 3 or 4 adverse events (5.5%, 3 of 55). During mean follow-up of 28.6±20.3 months (range 1 to 98), local tumor progression was found in 5 patients (11.4%, 5 of 44). The 1-, 3-, and 5-year overall survival rates were 97.7, 72.9, and 55.7%, respectively. The 1- and 3-year recurrence-free survival rates were 76.7 and 41.1%, respectively. Tumor size and sex were independent significant prognostic factors in multivariate analysis. The 5-year survival rates were 73.3% in 18 women and 60.5% in 38 patients who had small tumors measuring≤3 cm. CONCLUSION: Our results suggest that lung RF ablation is a safe and useful therapeutic option for obtaining long-term survival in treated patients.

Computer-aided detection scheme for sentinel lymph nodes in lymphoscintigrams using symmetrical property around mapped injection point.

It is difficult to detect sentinel lymph nodes (SLNs) around an injection point of radiopharmaceuticals mapped in lymphoscintigrams. The purpose of this study was to develop a computer-aided detection (CAD) scheme for SLNs by a subtraction technique using the symmetrical property in the mapped injection point. Our database consisted of 78 lymphoscintigrams with 86 SLNs. In our CAD scheme, the mapped injection point of radiopharmaceuticals was first segmented from the lymphoscintigram using a gray-level thresholding technique. Lymphoscintigram was then divided into four regions by vertical and horizontal straight lines through the center of the segmented injection point. One of the four divided regions was defined as the target region. The correlation coefficients based on pixel values were calculated between the target region and each of the other three regions. The region with the highest correlation coefficient among three regions was selected as the similar region to the target region. The values of pixels on the target region were subtracted by the values of the corresponding pixels on the similar region. This procedure was repeated until every divided region had been used as target region. SLNs were segmented by applying a gray-level thresholding technique to the subtracted image. With our CAD scheme, sensitivity and the number of false positives were 95.3% (82/86) and 2.51 per image, respectively. Our CAD scheme achieved a high level of detection accuracy, and would have a great potential in assisting physicians to detect SLNs in lymphoscintigrams.

Radiofrequency ablation combined with chemoembolization: treatment of recurrent hepatocellular carcinomas after hepatectomy.

OBJECTIVE: The purpose of this study is to evaluate the treatment effect and prognostic factors of radiofrequency ablation (RFA) combined with chemoembolization for patients with recurrent hepatocellular carcinomas (HCCs) after hepatectomy. MATERIALS AND METHODS: Fifty-five consecutive patients who received combination therapy as a curative treatment of recurrent HCCs after hepatectomy were included in this retrospective study. The mean maximum tumor diameter was 2.2 cm (range, 1.0-4.8 cm). Under CT fluoroscopic guidance, RFA was performed 1-2 weeks after chemoembolization. Technique effectiveness rates, complications, local tumor progression rates, survival rates, and prognostic factors were evaluated. RESULTS: Tumor enhancement disappeared on contrast-enhanced CT images in all patients after 72 RFA sessions (technique effectiveness rate, 100%). Pneumothorax requiring chest drainage was the only major complication that developed in one RFA session (1%). Four of 55 patients (7%) showed local tumor progression. New tumors emerged in the untreated liver in 27 patients (49%) during the mean follow-up of 35 months (range, 1-82 months). The 5-year overall and recurrence-free survival rates after combination therapy were 74% (95% CI, 54-87%) and 28% (95% CI, 14-45%), respectively. The presence of a single tumor at initial hepatectomy and a low α-fetoprotein level (≤ 100 ng/mL) at recurrence were significantly favorable independent factors affecting overall and recurrence-free survival. CONCLUSION: For treatment of recurrent HCCs after hepatectomy, RFA combined with chemoembolization is a useful therapeutic option. This study identified prognostic factors that will help to stratify patients with recurrent HCCs after hepatectomy.

Percutaneous radiofrequency ablation for pulmonary metastases from hepatocellular carcinoma: results of a multicenter study in Japan.

PURPOSE: To retrospectively evaluate technical success, effectiveness, complications, patient survival, and prognostic factors with percutaneous radiofrequency (RF) ablation for pulmonary metastases resulting from hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Thirty-two patients from six institutions were included, with a total of 83 pulmonary metastases treated in 65 sessions. RF ablation was always performed percutaneously with computed tomography (CT) guidance. Primary endpoints were technical success and technique effectiveness. Technique effectiveness was evaluated based on sequential follow-up CT images. Secondary study endpoints were complications, patient survival, and determination of prognostic factors. Complications were classified as major or minor. Prognostic factors were determined by analyzing multiple variables with the log-rank test. RESULTS: Technical success rate was 100%. Primary technique effectiveness rates were 92% each at 1, 2, and 3 years. Major and minor complications occurred after 16 (25%) and 23 (35%) of the 65 sessions, respectively. The median follow-up period was 20.5 months. Overall survival rates were 87% at 1 year and 57% each at 2 and 3 years (median and mean survival times, 37.7 mo and 43.2 mo, respectively). Significantly better survival rates were obtained in cases of (i) no viable intrahepatic recurrence (P < .001), (ii) Child-Pugh class A disease (P < .001), (iii) absence of liver cirrhosis (P < .001), (iv) absence of hepatitis C virus infection (P = .006), and (v) α-fetoprotein level of 10 ng/mL or lower (P = .007) at the time of RF ablation. CONCLUSIONS: RF ablation appears effective, with an acceptable safety profile, in selected patients with pulmonary metastases resulting from HCC.

Management of renal tumors in Von Hippel-Lindau disease by percutaneous CT fluoroscopic guided radiofrequency ablation: preliminary results.

We evaluated the feasibility and safety of percutaneous radiofrequency (RF) ablation of renal cell carcinomas (RCCs) in patients with Von Hippel-Lindau (VHL) disease. A total of 12 RCCs were treated by RF ablation in 7 patients with VHL disease. RF electrodes were placed under CT fluoroscopic guidance with conscious sedation. Technical success, technical effectiveness (disappearance of tumor enhancement), local tumor progression, complications and change in the estimated glomerular filtration rate (eGFR) were evaluated. A total of 9 sessions were undertaken. All procedures were performed with a planned protocol with a technical success rate of 100%. Tumor enhancement disappeared in all 12 tumors indicating a technical effectiveness rate of 100%. Local tumor progression was not found in any patient during the mean follow-up of 22 ± 11 months (range 12-46 months). There were no complications related to the RF procedures. The mean eGFR decreased from 65.3 ± 10.9 ml/min (range 48.5-77.5 ml/min) to 60.3 ± 11.3 ml/min (range, 45.8-73.4 ml/min, P < 0.03). The mean percentage decrease in eGFR after the last ablation was 7.6% (range 0-21.6%). Renal RF ablation is a safe and effective treatment for renal tumours that may allow patients with VHL disease to avoid major surgical interventions.

Quantification of myocardial blood flow using model based analysis of first-pass perfusion MRI: extraction fraction of Gd-DTPA varies with myocardial blood flow in human myocardium.

For the absolute quantification of myocardial blood flow (MBF), Patlak plot-derived K1 need to be converted to MBF by using the relation between the extraction fraction of gadolinium contrast agent and MBF. This study was conducted to determine the relation between extraction fraction of Gd-DTPA and MBF in human heart at rest and during stress. Thirty-four patients (19 men, mean age of 66.5 ± 11.0 years) with normal coronary arteries and no myocardial infarction were retrospectively evaluated. First-pass myocardial perfusion MRI during adenosine triphosphate stress and at rest was performed using a dual bolus approach to correct for saturation of the blood signal. Myocardial K1 was quantified by Patlak plot method. Mean MBF was determined from coronary sinus flow measured by phase contrast cine MRI and left ventricle mass measured by cine MRI. The extraction fraction of Gd-DTPA was calculated as the K1 divided by the mean MBF. The extraction fraction of Gd-DTPA was 0.46 ± 0.22 at rest and 0.32 ± 0.13 during stress (P < 0.001). The relationship between extraction fraction (E) and MBF in human myocardium can be approximated as E = 1 - exp(-(0.14 × MBF + 0.56)/MBF). The current results indicate that MBF can be accurately quantified by Patlak plot method of first-pass myocardial perfusion MRI by performing a correction of extraction fraction.

Adrenal radiofrequency ablation in swine: change in blood pressure and histopathologic analysis.

PURPOSE: To evaluate changes in blood pressure during adrenal radiofrequency ablation (RFA) and analyze histopathologic outcomes in swine adrenal glands. MATERIALS AND METHODS: Animal Care Committee approval was obtained for this study. After laparotomy, a single adrenal gland was ablated from each of six animals (six RF sessions total). An internally cooled-tip RF electrode was placed along the long axis of the adrenal gland, and RF energy was applied for 10 min in each adrenal gland. Blood pressure and heart rate were monitored, and serum epinephrine, norepinephrine, and cortisol levels were measured before, during, and after RFA. Histological study was performed using hematoxylin-eosin staining. RESULTS: RFA was completed according to a planned protocol in all adrenal glands. Blood pressure increased to >200 mm Hg after an increase in heart rate during all six RF sessions. Mean serum epinephrine and norepinephrine levels increased significantly during RFA. However, mean cortisol levels showed no significant increase during or after RFA. Histological studies showed adrenal cell necrosis throughout the adrenal glands in all but one pig, with the mean necrosis rate being 99.1 ± 2.3% (range 94.3-100%). CONCLUSION: Adrenal RFA causes extensive adrenal cell damage and causes catecholamine-induced hypertension.