Materials and Methods: The study protocol was approved by the institutional review board, and all patients gave written informed consent. One hundred eighty-one patients (79 men, 102 women; age range, 36–85 years) underwent ultrasonographically (US) guided percutaneous RF ablation of 361 primary or secondary (metastatic) liver tumors. Forty-four patients had one or more subcapsular nodules (group 1), and 137 had nonsubcapsular nodules only (group 2). Overall, 80 nodules were subcapsular and 281 were nonsubcapsular. The completeness of the ablation was assessed with contrast material–enhanced computed tomography (CT) 1 month after RF ablation. If residual tumor was documented, RF ablation was repeated. All patients in whom the ablation was complete after the first or second ablation session were monitored with CT or contrast-enhanced US every 3 months. Major complication, complete ablation, and local tumor progression rates were compared by using the ² test or Fisher exact test.

Results: Three (7%) major complications (intraperitoneal bleeding, skin burn, and tumor seeding) occurred in group 1, and two (1.5%) cases of tumor seeding occurred in group 2 (P = .093). No RF ablation–related deaths occurred. The complete ablation rate was 98% (43 of 44 patients) in group 1 and 98.5% (135 of 137 patients) in group 2 (P = .756). The local tumor progression rate after a median follow-up of 25 months (range, 13–54 months) was 16% (seven of 43 patients) in group 1 and 9.6% (13 of 135 patients) in group 2 (P = .355).

Conclusion: The difference in major complication rate between the subcapsular and nonsubcapsular liver tumors was not significant. The safety of RF ablation of subcapsular tumors seems acceptable, and the effectiveness is comparable to that of RF ablation of nonsubcapsular tumors.

© RSNA, 2008

Materials and Methods: Forty-five consecutive patients (27 men, 18 women; mean age, 64 years) underwent contrast material–enhanced MR angiography of the lower extremities at 3.0 T. A waiver of informed consent was granted by the institutional review board. Sixteen patients received high-dose (approximately 0.3 mmol/kg), 15 received intermediate-dose (approximately 0.2 mmol/kg), and 14 received low-dose (approximately 0.1 mmol/kg) gadopentetate dimeglumine during a three-station, dual-injection examination. For scoring purposes, the arterial system from the celiac trunk to the plantar arteries was divided into 34 segments. The images were retrospectively and independently evaluated by two specialized radiologists who were blinded to the patient dose groups. All studies were assessed for overall image quality and the degree of contaminating venous enhancement. Each arterial segment was scored for the quality of vessel definition, the severity of stenoses, and the presence of collateral vessels.

Results: More than 99% of arterial segments were found to be of diagnostic image quality by both readers in all dose groups. Generalized estimating equation analysis showed a significant difference among the three groups with regard to vessel definition (P = .019). No significant difference was found between the high- and intermediate-dose groups; however, the low-dose group had significantly better vessel definition compared with the high-dose (P = .034) and intermediate-dose (P = .015) groups. There was no significant difference among the groups in visualization of collateral vessels. Venous contamination was seen less frequently in the low-dose group, but the difference did not achieve significance.

Conclusion: The study showed that, compared with widely used dose strategies at 1.5 T, the contrast agent dose for 3.0-T lower extremity MR angiography can be reduced multifold without compromising image quality.

© RSNA, 2008

Materials and Methods: Twenty-six patients (four women, 22 men; median age, 72 years) with cirrhosis (Child-Pugh class A disease, 22 patients; Child-Pugh class B disease, four patients) and at least one 5.0–9.0-cm-diameter HCC without invasion of the portal trunk or main portal branches were treated with multipolar RF ablation performed by a single operator. The procedure was performed with three separate bipolar linear internally cooled electrodes with ultrasonographic guidance. Twenty-seven of the 33 tumors treated had a diameter of 5.0 cm or greater (median diameter, 5.7 cm; range, 5.0–8.5 cm); 12 of these 27 tumors were infiltrative, and four invaded segmental portal vein branches. Ten patients had a serum -fetoprotein level higher than 400 µg/L. Results were assessed by using computed tomography. Primary effectiveness, complications, tumor progression, and survival rates were recorded. Probabilities of survival were calculated by using the Kaplan-Meier method.

Results: One to two RF ablation procedures per patient (mean, 1.15 ± 0.43 [standard deviation]) led to the complete ablation of 22 (81%) of the 27 tumors (18 tumors after one and four tumors after two procedures), including three tumors that showed segmental portal vein invasion. All patients experienced postablation syndrome, and one experienced subcapsular hematoma and a segmental liver infarct, but no major complication occurred. After a mean follow-up of 14 months (range, 3–34 months), local and distant tumor progression and actual survival rates were 14% (three of 22), 24% (five of 21), and 65% (17 of 26), respectively. The probabilities of 1- and 2-year survival, respectively, were 68% (95% confidence interval: 49%, 86%) and 56% (95% confidence interval: 51%, 81%).

Conclusion: HCCs larger than 5.0 cm (but smaller than 9.0 cm)—even those that are infiltrative and those that involve a segmental portal vein—can be completely and safely ablated with multipolar RF ablation.

© RSNA, 2008

Materials and Methods: Patients with symptomatic femoropopliteal in-stent restenosis were randomly assigned to undergo CBA or peripheral cutting balloon angioplasty (PCBA) for treatment of lesions up to 20 cm in length. Patients were followed up clinically and with duplex ultrasonography (US) at 1, 3, and 6 months for occurrence of a restenosis of 50% or higher. The Fisher exact test and Mann Whitney U test were used for statistical analyses.

Results: Forty patients were enrolled; one patient was lost to follow-up. In the remaining patients, CBA was performed in 22 patients; PCBA was used in 17 patients. Average lesion length was 80 mm ± 68 (standard deviation). Restenosis rates at 6 months were 65% (11 of 17; 95% confidence interval: 42%, 88%) after PCBA versus 73% (16 of 22; 95% confidence interval: 54%, 92%) after CBA (P = .73). Ankle brachial index (0.83 vs 0.75, P = .26) and maximum walking capacity on the treadmill (117 m vs 103 m, P = .97) at 6 months were also not significantly different between the two groups.

Conclusion: PCBA failed to prove superiority compared with CBA for treatment of femoropopliteal in-stent restenosis in this pilot study. In restenotic lesions with an average length of approximately 8 cm, both treatment modalities yielded disappointing 6-month patency rates.

© RSNA, 2008

Materials and Methods: This HIPAA-compliant study had institutional review board approval. Informed consent was waived. Biochemical and hematologic laboratory values from 48 procedures in 39 patients (18 men and 21 women; age range, 29–86 years) who underwent magnetic resonance (MR) imaging–guided percutaneous cryoablation of 65 liver tumors (62 metastases, three hepatocellular carcinomas) were retrospectively reviewed. Changes in laboratory values at baseline and 0–6 hours and 1–2 weeks after the procedure were analyzed with respect to tumor and ablative margin volumes by using generalized estimating equations. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were correlated with percent maximal decrease in platelet count.

Results: Mean ablation zone volume was 67.3 cm³ ± 41.2 (standard deviation) (range, 7.3–191.4 cm³). AST and ALT values increased after all procedures and peaked at 6 hours (median change in AST value, +835 U/L; median change in ALT value, +614.5 U/L). Platelet count decreased after 47 procedures (mean maximal decrease, 92.3 x 10⁹/L [38%]), reaching a nadir at 12–24 hours after 24 procedures (50%) and returning to normal in 31 (84%) of 37 procedures at 1–2 weeks. One procedure was complicated by disseminated intravascular coagulation that necessitated transfusion and arterial embolization. Myoglobin values increased after 21 (44%) of 48 procedures and peaked at 6 hours (trimmed-mean value, 183.4 µg/L). Ablative margin volumes were predictive of changes at 0–6 hours in AST (P = .02), ALT (P = .003), and myoglobin (P < .001) values. Percent maximal decrease in platelet count correlated with peak change in AST (r = 0.72) (P < .001).

Conclusion: Following percutaneous cryoablation of liver tumors, alterations in liver enzymes, myoglobin, and platelet count are common, are usually self-limited, and correlate with ablative margin volume—except for changes in platelet count, which correlate with changes in AST and ALT.

© RSNA, 2008

Materials and Methods: This HIPAA-compliant study was approved by the institutional review board; informed consent was waived. From November 10, 2003, to August 28, 2006, 82 masses (mean, 1.42 per patient) in 50 patients (28 men, 22 women; mean age, 70 years) were percutaneously treated in 66 microwave ablation sessions. Each tumor was ablated with computed tomographic (CT) guidance. Follow-up contrast material–enhanced CT and positron emission tomographic (PET) scans were reviewed. Mixed linear modeling and logistic regression were performed. Time-event data were analyzed (Kaplan-Meier survival estimates and log-rank statistic). All event times were the time to a patient's first event ( level = .05, all analyses).

Results: At follow-up (mean, 10 months), 26% (13 of 50) of patients had residual disease at the ablation site, predicted by using index size of larger than 3 cm (P = .01). Another 22% (11 of 50) of patients had recurrent disease resulting in a 1-year local control rate of 67%, with mean time to first recurrence of 16.2 months. Kaplan-Meier analysis yielded an actuarial survival of 65% at 1 year, 55% at 2 years, and 45% at 3 years from ablation. Cancer-specific mortality yielded a 1-year survival of 83%, a 2-year survival of 73%, and a 3-year survival of 61%; these values were not significantly affected by index size of larger than 3 cm or 3 cm or smaller or presence of residual disease. Cavitation (43% [35 of 82] of treated tumors) was associated with reduced cancer-specific mortality (P = .02). Immediate complications included pneumothorax (Common Terminology Criteria for Adverse Events [CTCAE] grades 1 [18 of 66 patients] and 2 [eight of 66 patients]), hemoptysis (four of 66 patients), and skin burns (CTCAE grades 2 [one of 66 patients] and 3 [one of 66 patients]).

Conclusion: Microwave ablation is effective and may be safely applied to lung tumors.

© RSNA, 2008

Materials and Methods: This study was approved by the committee on human research and was deemed compliant with the Health Insurance Portability and Accountability Act. The informed consent requirement was waived. Records of 1394 procedures (307 PTCs, 1087 PTBDs) performed in 930 patients (445 male, 485 female; age range, 4 months to 99 years) over the past 13 years were retrospectively reviewed. The rate of AI was determined, and demographic, pathologic, technical, and laboratory variables were tested for association with increased risk of AI by using generalized estimating equation analysis.

Results: AIs were encountered after 30 (2.2%) biliary procedures. No significant difference in the rate of AI was seen among the groups of patients with malignant biliary obstruction (1.8%), history of bile duct injury (2.2%), or complications of liver transplantation (2.6%). Patients who underwent PTBD had a higher risk of AI than did patients who underwent PTC (2.6% vs 0.7%); however, this difference was not significant (P = .06). Ongoing hemobilia was seen in 26 (87%) of the patients, which made it the most common sign of AI, and it had a 94% positive predictive value for AI. A postprocedure decrease in the hematocrit level of more than 13% was seen only in the setting of AI, and it occurred in only three (10%) of patients with AIs.

Conclusion: PTC and PTBD performed for management of bile duct injury and complications of liver transplantation are not associated with an increased risk of hepatic AIs compared with the risk of AI reported in the 1970s and 1980s.

© RSNA, 2008

Materials and Methods: The study was approved by the Institutional Review Board; informed consent was obtained from patients. MR venography was performed before surgery in 22 legs of 14 patients (seven women: mean age, 53 years; seven men: mean age, 59 years) thought to have recurrent varicose veins. Two radiologists assessed image quality and evaluated sites and sources of varicose veins on MR venograms. One vascular surgeon completed a questionnaire before and after MR venography and noted diagnosis and therapeutic decisions. Diagnoses at MR venography were compared with surgical results in 19 legs that underwent surgery. Differences between diagnosed and treated varicose veins per leg before and after MR venography were analyzed with logistic regression for survey data. Values were calculated to illustrate interobserver agreement for grading image quality of venous segments and for diagnosing recurrent varicose veins.

Results: Mean graded image quality of the deep venous system and the recurrent varicose veins was good or excellent in 89% of segments. There was good agreement between readers regarding grading of image quality of venous segments ( = 0.80). After MR venography, diagnosis of the sites and sources of recurrent varicose veins changed in 17 of 22 legs of nine of 14 patients. In one of 14 patients, the preoperative diagnosis of recurrent varicose veins was withdrawn. A change in treatment plan occurred in 17 of 22 legs after MR venography. The number of diagnosed and treated sources of reflux increased significantly after MR venography. MR venographic diagnoses were confirmed at surgery in all 19 legs.

Conclusion: MR venographic results have a substantial effect on diagnostic thinking and therapeutic decisions when recurrent lower-limb varicose veins are suspected.

© RSNA, 2008

Materials and Methods: This HIPAA–compliant study was approved by the Institutional Review Board with waiver of informed consent. Twenty-six patients (14 men, 12 women; mean age, 56 years), in whom intraoperative Inline and TissueLink devices were used for resection of hepatocellular carcinoma or metastatic liver disease or other liver tumors, were identified. Information such as tumor characteristics, diagnostic studies, surgical therapy, and surveillance methods were reviewed. All computed tomographic (CT) and positron emission tomographic (PET) scans and the single magnetic resonance and ultrasonographic images of the abdomen were retrospectively reviewed by a radiologist and compared with the initial interpreting physician's report.

Results: Of 35 CT scans, 33 revealed a hypodense line of demarcation (mean thickness, 13.2 mm) between the surgical resection clips and the normal liver parenchyma. This demarcation was interpreted as "could not exclude site recurrence" in three cases and "recurrence or probable recurrence" in five cases. In two CT scans, the hypodense demarcation was not present. In all seven PET scans, the uniform hypermetabolic activity associated with the demarcation was labeled as a recurrence. At follow-up CT (median, 12.5 months), marginal recurrence was not detected in 25 patients, though in one case there was a recurrence in close proximity to the surgical site.

Conclusion: The use of InLine and TissueLink devices during hepatectomy is associated with a linear hypodense demarcation at the surgical margin that also demonstrates a symmetrical rimlike hypermetabolic activity seen on PET scans.

© RSNA, 2008

Materials and Methods: This HIPAA-compliant study was approved by the Institutional Review Board; informed consent was waived. Forty-three patients (17 men, 26 women; mean age, 46 years; age range, 10–89 years) with a total of 46 abscesses underwent percutaneous drainage with 8.5–14-F catheters. Etiology was postoperative in 28 abscesses (60.9%) and varied in 18 (39.1%). Intracavitary tPA was initiated on the basis of viscous contents yielding minimal drainage at initial placement or if follow-up imaging showed a large residual collection despite satisfactory catheter position. A treatment cycle was 4–6 mg of tPA in 0.9% saline administered twice daily for 3 days. Drainage success was defined as evacuation of the abscess without surgery. Safety was evaluated on the basis of complications. Statistical analysis was performed by using the Student t test and Fisher exact test.

Results: Forty-six abscesses were initially drained by 51 catheters. Complete evacuation was achieved in 41 (89.1%) abscesses, whereas five (10.9%) required surgical drainage. Three (60%) of these five had a documented fistula, a higher (P = .02) percentage than in successfully drained abscesses. Three (6.5%) of the 46 abscesses recurred (12–95 days after catheter removal). There were no tPA-linked bleeding complications despite four patients receiving full systemic anticoagulation and 24 receiving prophylactic anticoagulation.

Conclusion: Intracavitary tPA is safe and effective for draining complex fluid collections, with most patients avoiding surgery.

© RSNA, 2008

Materials and Methods: The study protocol was approved by the institutional ethics committee, and informed consent was obtained from each patient. Patients from one institution who had dysphagia caused by inoperable esophageal cancer were randomly assigned to receive treatment with a stent loaded with ¹²⁵I seeds (irradiation stent group) or a conventional covered stent (control group). After stent implantation, the outcomes were measured in terms of relief of dysphagia, survival time, and complications related to the procedure. Dysphagia was assigned a grade. A P value of less than .05 was considered to indicate a significant difference.

Results: The stent was successfully placed in the diseased esophagus in all 53 patients (27 patients in the irradiation stent group and 26 patients in the control group). The dysphagia grades significantly improved in both groups within the 1st month after stent placement but were better in the irradiation stent group than in the control group after 2 months (P < .05). The median and mean survival times were better in the irradiation stent group than in the control group, and the differences were significant (P < .001). Hemorrhage occurred in 16 (30%) patients in both groups combined during follow-up.

Conclusion: In patients with advanced esophageal cancer, treatment with an esophageal stent loaded with ¹²⁵I seeds, compared with that with a conventional covered stent, has potential benefit in that it allows a slightly longer relief of dysphagia and extended survival.

© RSNA, 2008