Combination Radiofrequency Ablation and Percutaneous Osteoplasty for Palliative Treatment of Painful Extraspinal Bone Metastasis: A Single-Center Experience

PurposeTo evaluate combined radiofrequency (RF) ablation and percutaneous osteoplasty (POP) in patients with painful extraspinal bone metastases.Materials and MethodsIn a retrospective study, 38 patients with 54 extraspinal bone metastases (ilium, n = 24; acetabulum, n = 21; femur, n = 7; ischium, n = 1; tibia, n = 1) were treated with RF ablation and POP. All patients had pain refractory to analgesic medication with intensity > 3 on a visual analog scale (VAS). Changes in quality of life were evaluated based on pain relief (VAS score), function on a Karnofsky performance scale, and analgesic dose before and immediately after the procedure and during follow-up. VAS score was the primary outcome, and the others were secondary outcomes.ResultsTechnical success was achieved in 37 patients (97.4%). Mean VAS score declined significantly from 7.1 ± 1.5 before treatment to 2.2 ± 2.0 at 24 hours after treatment (P < .05), 1.6 ± 1.8 at 3 months after treatment (P < .05), and 1.3 ± 1.8 at 6 months after treatment (P < .05). Pain relief immediately after the procedure was reported by 35 patients (92.1%); pain regressed completely in 7 (18.4%) patients. After 6 months, narcotic analgesia had been suspended in 32 of 33 patients (97.0%). Pain was controlled by nonsteroidal antiinflammatory drugs in 8 patients (24.2%), and no analgesia was necessary in 24 patients (72.7%). Mean Karnofsky performance scale score after treatment was higher than before treatment (P < .05). The major complication rate was 2.6% (1 of 38 patients), with one case of vasovagal shock. The minor complication rate was 23.7% (9 of 38 patients).ConclusionsRF ablation with POP is effective for pain relief and functional recovery in patients with painful extraspinal bone metastases and can significantly improve quality of life.     

Clinical Impact of Sacroplasty on Patient Mobility

PurposeTo evaluate the effect of sacroplasty on patient mobility and pain when performed as a treatment for sacral insufficiency fractures.Materials and MethodsImaging with computed tomography (CT), magnetic resonance imaging, or bone scan confirmed the diagnosis of sacral insufficiency fractures. Baseline clinical mobility scale (CMS) score and visual analog scale (VAS) pain score were recorded. Sacroplasty was performed under CT guidance. Follow-up CMS and VAS scores were assessed at 4, 24, and 48 weeks.ResultsEighteen elderly patients (age 80 y ± 8.5; 17 women) were treated. Repeated-measures analysis of variance was conducted to assess changes in CMS and VAS scores over time. Pairwise comparisons revealed a significant increase in average CMS score between baseline and all three follow-up points—4 weeks (P < .001), 24 weeks (P < .001), and 48 weeks (P < .001)—indicating improvement in mobility over time. Pairwise comparisons revealed significant differences in mean VAS scores between baseline and all three follow-up time points—4 weeks (P < .001), 24 weeks (P < .001), and 48 weeks (P < .001)—indicating improvement in overall pain level over time.ConclusionsTreatment with CT-guided sacroplasty for sacral insufficiency fractures in this elderly population resulted in significant improvement in patient mobility.     

Percutaneous Vertebroplasty Combined with Zoledronic Acid for the Treatment of Painful Osteolytic Spinal Metastases in Patients with Breast Cancer

PurposeTo assess retrospectively the efficacy and safety of percutaneous vertebroplasty (PVP) combined with zoledronic acid (ZA) for the treatment of painful osteolytic spinal metastases from breast cancer.Materials and MethodsPVP was performed in 43 patients with breast cancer and painful osteolytic spinal metastases; 126 vertebrae were treated. The patients subsequently received 4 mg ZA via a 15-minute intravenous infusion every 4 weeks for 12 months. Pain and quality of life (QoL) were assessed using a visual analog scale (VAS) and Karnofsky performance scale (KPS), respectively, 24 hours before PVP and 24 hours, 1 month, 3 months, 6 months, and 12 months after PVP. Skeletal-related events (SREs) were assessed for 12 months following the intervention.ResultsThe mean VAS scores decreased significantly from 7.6 ± 1.9 at 24 hours before PVP to 3.6 ± 1.4 at 24 hours, 2.0 ± 1.5 at 1 month, 2.8 ± 1.6 at 3 months, 3.1 ± 0.8 at 6 months, and 2.5 ± 0.9 at 12 months after the intervention (P < .05). KPS scores increased significantly after the combination treatment (P < .05). Compared with previous studies without PVP or ZA treatment, this patient group had a lower incidence of SREs. No major complications were observed.ConclusionsPVP combined with ZA was shown to be a highly effective and safe combination therapy to relieve pain and improve QoL in patients with osteolytic spinal metastases from breast cancer. The combination therapy also prevented the occurrence of SREs.     

Radiofrequency Ablation–Induced Upregulation of Hypoxia-Inducible Factor-1α Can Be Suppressed with Adjuvant Bortezomib or Liposomal Chemotherapy

PurposeTo characterize upregulation of hypoxia-inducible factor (HIF)-1α after radiofrequency (RF) ablation and the influence of an adjuvant HIF-1α inhibitor (bortezomib) and nanodrugs on modulating RF ablation–upregulated hypoxic pathways.Materials and MethodsFisher 344 rats (n = 68) were used. First, RF ablation–induced periablational HIF-1α expression was evaluated in normal liver or subcutaneous R3230 tumors (14–16 mm). Next, the effect of varying RF ablation thermal dose (varying tip temperature 50°C–90°C for 2–20 minutes) on HIF-1α expression was studied in R3230 tumors. Third, RF ablation was performed in R3230 tumors without or with an adjuvant HIF-1α inhibitor, bortezomib (single intraperitoneal dose 0.1 mg/kg). Finally, the combination RF ablation and intravenous liposomal chemotherapeutics with known increases in periablational cellular cytotoxicity (doxorubicin, paclitaxel, and quercetin) was assessed for effect on periablational HIF-1α. Outcome measures included immunohistochemistry of HIF-1α and heat shock protein 70 (marker of nonlethal thermal injury).ResultsRF ablation increased periablational HIF-1α in both normal liver and R3230 tumor, peaking at 24–72 hours. Tumor RF ablation had similar HIF-1α rim thickness but significantly greater percent cell positivity compared with hepatic RF ablation (P < .001). HIF-1α after ablation was the same regardless of thermal dose. Bortezomib suppressed HIF-1α (rim thickness, 68.7 µm ± 21.5 vs 210.3 µm ± 85.1 for RF ablation alone; P < .02) and increased ablation size (11.0 mm ± 1.5 vs 7.7 mm ± 0.6 for RF ablation alone; P < .002). Finally, all three nanodrugs suppressed RF ablation–induced HIF-1α (ie, rim thickness and cell positivity; P < .02 for all comparisons), with liposomal doxorubicin suppressing HIF-1α the most (P < .03).ConclusionsRF ablation upregulates HIF-1α in normal liver and tumor in a temperature-independent manner. This progrowth, hypoxia pathway can be successfully suppressed with an adjuvant HIF-1α-specific inhibitor, bortezomib, or non–HIF-1α-specific liposomal chemotherapy.     

Serum MicroRNA-210 as a Predictive Biomarker for Treatment Response and Prognosis in Patients with Hepatocellular Carcinoma undergoing Transarterial Chemoembolization

PurposeTo investigate whether serum microRNA-210 (miR-210) level can serve as an indicator of prognosis and a predictor of efficacy of transarterial chemoembolization in patients with hepatocellular carcinoma (HCC).Materials and MethodsSerum miR-210 level was measured in 113 patients with HCC before transarterial chemoembolization (t1), 3 days after transarterial chemoembolization (t2), and 4 weeks after transarterial chemoembolization (t3) and compared with 39 healthy control subjects. The correlations between miR-210 levels and clinicopathologic factors, tumor responsiveness, and prognosis were analyzed. The modified Response Evaluation Criteria in Solid Tumors assessment was conducted at t3.ResultsA higher mean baseline miR-210 level was observed in patients with HCC compared with control subjects (3.69 ± 2.04 vs 1.08 ± 0.45, P < .001). A positive correlation between baseline miR-210 level and tumor size (P < .001), vascular invasion (P = .005), tumor differentiation (P = .037), and Barcelona Clinic Liver Cancer stage (P < .001) was observed. Elevated baseline miR-210 level also served as an independent prognostic factor predicting poor overall survival (risk ratio, 2.082; P = .003). Patients who did not respond to transarterial chemoembolization had higher baseline miR-210 levels than patients who did respond to treatment (4.34 ± 1.67 vs 3.28 ± 2.15, P < .001). In addition, miR-210 levels increased significantly 4 weeks after transarterial chemoembolization in nonresponders (5.79 ± 2.06 at t3 vs 4.34 ± 1.67 at t1, P < .001), whereas no significant change was observed in responders (3.53 ± 2.20 at t3 vs 3.28 ± 2.15 at t1, P = .116). Lastly, an inverse correlation was identified between miR-210 change t1–t3 with the time to radiologic progression (P < .001).ConclusionsSerum miR-210 may represent a novel biomarker for predicting efficacy of transarterial chemoembolization and overall survival for patients with HCC.     

Comparison of Characteristics and Transarterial Chemoembolization Outcomes in Patients with Unresectable Hepatocellular Carcinoma and Different Viral Etiologies

PurposeTo determine any differences in patient characteristics and outcomes after transarterial chemoembolization between different viral etiologies of hepatocellular carcinoma (HCC).MethodsThis retrospective study consisted of 201 patients undergoing first-time transarterial chemoembolization for unresectable HCC from January to December 2009. The patients were divided into four groups: hepatitis B virus (HBV) only (n = 104), hepatitis C virus (HCV) only (n = 63), HBV and HCV (n = 10), and no viral hepatitis (n = 24). The clinical and laboratory data were obtained from electronic medical records, and imaging findings obtained before transarterial chemoembolization were analyzed. Kaplan-Meier analyses were used to assess the impact of HBV or HCV status, clinical characteristics, and imaging results on overall survival.ResultsAfter a median follow-up of 28.3 months ± 16.2, the 1-, 2-, and 3-year overall survival rates were 74.1%, 59.7%, and 53.2%. Patients with HBV had a significant association with younger age (P = .001), higher male-to-female ratio (P = .003), lower alanine aminotransferase levels (P = .018), higher albumin levels (P = .009), and multifocal tumors at diagnosis (P = .04) compared with patients with HCV. Patients with both HBV and HCV had significantly higher serum bilirubin levels compared with the other groups (P = .002). No significant difference was found in overall survival among the different hepatitis groups (P = .943). Multivariate analysis showed that statistically significant determinants for overall survival were Child-Pugh class (P = .002), Barcelona Clinic Liver Cancer stage (P < .001), tumor size (P < .001), and distribution (P < .001).ConclusionsViral etiology has no correlation with the outcome of patients with HCC undergoing transarterial chemoembolization.     

Repeated Percutaneous Radiofrequency Ablation for Hepatocellular Carcinoma in Patients with Cirrhosis: Assessment of Safety Based on Liver Function and Portal Hypertension Parameters

PurposeTo evaluate changes in liver function and portal hypertension parameters after repeated percutaneous radiofrequency (RF) ablation for hepatocellular carcinoma (HCC) in patients with cirrhosis.Materials and MethodsThis study included 24 patients (male-to-female ratio, 15:9; mean age, 59.4 y) with early-stage HCC (mean tumor size, 1.91 cm) and cirrhosis who underwent three consecutive treatments with RF ablation between April 1999 and August 2011. Serial changes of liver function and portal hypertension parameters after repeated RF ablation were compared with baseline values using a mixed model and Wilcoxon signed rank test.ResultsThe interval between the first and second RF ablation measurements and between the second and third RF ablation measurements was 26.1 months ± 18.3 (range, 3.8–65.8 mo) and 16.6 months ± 9.8 (range, 4.7–35.4 mo), respectively. Total bilirubin level was significantly increased between the first RF ablation and 6 months after the third RF ablation (0.75 g/dL ± 0.37 to 1.06 g/dL ± 0.68, P = .001), but all values were within the normal range. No other liver function parameter showed a significant change (P > .05 for all). Portal hypertension parameters did not show significant changes between the first RF ablation and 6 months after the third RF ablation (P > .05).ConclusionsRepeated RF ablation for controlling recurrent HCC did not seem to affect liver function and portal hypertension in patients.     

Quantification of Tissue Shrinkage and Dehydration Caused by Microwave Ablation: Experimental Study in Kidneys for the Estimation of Effective Coagulation Volume

PurposeTo quantify the extent of tissue shrinkage and dehydration caused by microwave (MW) ablation in kidneys for estimation of effective coagulation volume.Materials and MethodsMW ablations were carried out in ex vivo porcine kidneys. Six study groups were defined: groups 1A, 2A, and 3A for MW ablation (90 W for 5 min, 7.5 min, or 10 min), and groups 1B, 2B, and 3B for control (without MW ablation). Pre- and postinterventional volume analyses were performed. Effective coagulation volumes (original tissue included in coagulation) were determined. Postinterventional dehydration analyses were performed with calculation of mean mass fractions of water.ResultsMean deployed energies were 21.6 kJ ± 1.1 for group 1A, 29.9 kJ ± 1.0 for group 2A, and 42.1 kJ ± 0.5 kJ for group 3A, and were significantly different (P < .0001). Differences between pre- and postinterventional volumes were ?3.8% ± 0.6 for group 1A, ?5.6% ± 0.9 for group 2A, and ?7.2% ± 0.4 for group 3A, and ?1.1% ± 0.3 for group 1B, ?1.8% ± 0.4 for group 2B, and ?1.1% ± 0.4 for group 3B. Postinterventional volumes were significantly smaller than preinterventional volumes for all groups (P < .01). Underestimations of effective coagulation volume from visualized coagulation volume were 26.1% ± 3.5 for group 1A, 35.2% ± 11.2 for group 2A, and 42.1% ± 4.9 for group 3A, which were significantly different (P < .01). Mean mass fractions of water were 64.2% ± 1.4 for group 1A, 63.2% ± 1.7 for group 2A, and 62.6% ± 1.8% for group 3A, with significant differences versus corresponding control groups (P < .01).ConclusionsFor MW ablation in kidneys, underestimation of effective coagulation volume based on visualized coagulation volume is significantly greater with greater deployed energy. Therefore, local dehydration with tissue shrinkage is a potential contributor.     

Modified Cisplatin-based Transcatheter Arterial Chemoembolization for Large Hepatocellular Carcinoma: Multivariate Analysis of Predictive Factors for Tumor Response and Survival in a 163-Patient Cohort

PurposeTo evaluate the safety and efficacy of modified cisplatin-based transcatheter arterial chemoembolization for inoperable hepatocellular carcinomas (HCCs) larger than 5 cm in diameter, and the factors associated with tumor response and survival.Materials and MethodsFrom January 2007 to November 2009, 163 patients who underwent modified cisplatin-based chemoembolization for inoperable large HCCs were evaluated. Predominant tumors were as large as 25 cm (median, 8.6 cm). Seventy-nine patients had a solitary tumor, and 84 had two or more tumors. Tumor response was evaluated per modified Response Evaluation Criteria In Solid Tumors.ResultsAfter chemoembolization, 65% of patients showed a tumor response. On multivariate analysis, tumor size (P < .001) and portal vein (PV) invasion (P = .017) were significant factors for tumor response. After chemoembolization, 97% of patients (56 of 58) with PV invasion received additional radiation therapy for PV tumor thrombosis. Median survival time was 15.8 months. On multivariate analysis, Child–Pugh class (P = .001), surgical resection (P = .003) or radiofrequency (RF) ablation (P = .018) after chemoembolization, and tumor response (P = .002) were significant factors for patient survival after chemoembolization. Major complications (N = 5) included acute renal failure (n = 3), cholecystitis with hepatic abscess (n = 1), and intractable pleural effusion (n = 1).ConclusionsTranscatheter arterial chemoembolization is safe and effective for large HCCs. Tumor size and PV invasion are significant predictors of tumor response and, Child–Pugh class A disease, surgical resection after chemoembolization, RF ablation after chemoembolization, and tumor response are good prognostic factors for survival.     

Transcatheter CT Arterial Portography and CT Hepatic Arteriography for Liver Tumor Visualization during Percutaneous Ablation

PurposeTo evaluate the feasibility of combining transcatheter computed tomography (CT) arterial portography or transcatheter CT hepatic arteriography with percutaneous liver ablation for optimized and repeated tumor exposure.Materials and MethodsStudy participants were 20 patients (13 men and 7 women; mean age, 59.4 y; range, 40–76 y) with unresectable liver-only malignancies—14 with colorectal liver metastases (29 lesions), 5 with hepatocellular carcinoma (7 lesions), and 1 with intrahepatic cholangiocarcinoma (2 lesions)—that were obscure on nonenhanced CT. A catheter was placed within the superior mesenteric artery (CT arterial portography) or in the hepatic artery (CT hepatic arteriography). CT arterial portography or CT hepatic arteriography was repeatedly performed after injecting 30–60 mL 1:2 diluted contrast material to plan, guide, and evaluate ablation. The operator confidence levels and the liver-to-lesion attenuation differences were assessed as well as needle-to-target mismatch distance, technical success, and technique effectiveness after 3 months.ResultsTechnical success rate was 100%; there were no major complications. Compared with conventional unenhanced CT, operator confidence increased significantly for CT arterial portography or CT hepatic arteriography cases (P < .001). The liver-to-lesion attenuation differences between unenhanced CT, contrast-enhanced CT, and CT arterial portography or CT hepatic arteriography were statistically significant (mean attenuation difference, 5 HU vs 28 HU vs 70 HU; P < .001). Mean needle-to-target mismatch distance was 2.4 mm ± 1.2 (range, 0–12.0 mm). Primary technique effectiveness at 3 months was 87% (33 of 38 lesions).ConclusionsIn patients with technically unresectable liver-only malignancies, single-session CT arterial portography–guided or CT hepatic arteriography–guided percutaneous tumor ablation enables repeated contrast-enhanced imaging and real-time contrast-enhanced CT fluoroscopy and improves lesion conspicuity.     

Does Polyvinyl Alcohol Particle Size Change the Outcome of Prostatic Arterial Embolization for Benign Prostatic Hyperplasia? Results from a Single-Center Randomized Prospective Study

PurposeTo evaluate whether different polyvinyl alcohol (PVA) particle sizes change the outcome of prostatic arterial embolization (PAE) for benign prostatic hyperplasia (BPH).Materials and MethodsA randomized prospective study was undertaken in 80 patients (mean age, 63.9 y; range, 48–81 y) with symptomatic BPH undergoing PAE between May and December 2011. Forty patients underwent PAE with 100-µm (group A) and 200-µm PVA particles (group B). Visual analog scales were used to measure pain, and rates of adverse events were recorded. PAE outcomes were evaluated based on International Prostate Symptom Score (IPSS) and quality-of-life (QoL) questionnaires, prostate volume (PV), prostate-specific antigen (PSA) levels, and peak flow rate measurements at baseline and 6 months.ResultsNo differences between groups regarding baseline data, procedural details, or adverse events were noted. Mean pain scores were as follows: during embolization, 3.2 ± 2.97 (group A) versus 2.93 ± 3.28 (group B); after embolization, 0.10 ± 0.50 (group A) versus 0 (group B; P = .20); and the week after PAE, 0.85 ± 1.65 (group A) versus 0.87 ± 1.35 (group B; P = .96). Patients in group B had greater decreases in IPSS (3.64 points; P = .052) and QoL (0.57 points; P = .07). Patients in group A had a greater decrease in PV (8.75 cm³; P = .13) and PSA level (2.09 ng/mL; P < .001).ConclusionsNo significant differences were found in pain scores and adverse events between groups. Whereas PSA level and PV showed greater reductions after PAE with 100-µm PVA particles, clinical outcome was better with 200-µm particles.     

Safety and Therapeutic Efficacy of Complete or Near-Complete Ablation of Symptomatic Uterine Fibroid Tumors by MR Imaging–Guided High-Intensity Focused US Therapy

PurposeTo evaluate the safety and therapeutic efficacy of magnetic resonance (MR) imaging–guided high-intensity focused ultrasound (US) ablation of symptomatic uterine fibroid tumors with an immediate nonperfused volume (NPV) ratio of 80% or more.Materials and MethodsA total of 79 women with 117 uterine tumors were treated with MR-guided high-intensity focused US ablation. Immediate NPV, complications, and therapeutic efficacy (tumor volume reduction ratio and symptom severity score [SSS] decrease at 3-mo follow-up) were retrospectively assessed. Statistical comparisons of the frequency of complications and therapeutic efficacy were performed between patients with NPV ratios of at least 80% and less than 80%.ResultsTechnical success was achieved in 93.7% of cases (n = 74) of cases, and the immediate NPV ratio was 62.7% ± 25.5. Twenty-four patients exhibited an NPV ratio of at least 80% (89.7% ± 5.8), and 50 patients showed an NPV ratio of less than 80% (49.8% ± 20.7). All complications were minor in severity, and the incidences were not significantly different between groups (P > .05). The 3-month volume reduction ratio was significantly greater in patients with an NPV ratio of at least 80% (0.43 ± 0.17) than in those with an NPV ratio of less than 80% (0.20 ± 0.26; P = .002), although the decreases in SSS were not significantly different (20.9 ± 19.6 vs 12.1 ± 10.1; P = .097).ConclusionsIn MR-guided high-intensity focused US ablation of symptomatic uterine fibroid tumors, achievement of an immediate NPV ratio of at least 80% is safe, with greater tumor volume shrinkage compared with cases with a lower NPV ratio.     

Image Guidance for Endovascular Repair of Complex Aortic Aneurysms: Comparison of Two-dimensional and Three-dimensional Angiography and Image Fusion

PurposeTo evaluate the feasibility of image fusion (IF) of preprocedural arterial-phase computed tomography with intraprocedural fluoroscopy for roadmapping in endovascular repair of complex aortic aneurysms, and to compare this approach versus current roadmapping methods (ie, two-dimensional [2D] and three-dimensional [3D] angiography).Materials and MethodsThirty-seven consecutive patients with complex aortic aneurysms treated with endovascular techniques were retrospectively reviewed; these included aneurysms of digestive and/or renal arteries and pararenal and juxtarenal aortic aneurysms. All interventions were performed with the same angiographic system. According to the availability of different roadmapping software, patients were successively placed into three intraprocedural image guidance groups: (i) 2D angiography (n = 9), (ii) 3D rotational angiography (n = 14), and (iii) IF (n = 14). X-ray exposure (dose–area product [DAP]), injected contrast medium volume, and procedure time were recorded.ResultsPatient characteristics were similar among groups, with no statistically significant differences (P ≥ .05). There was no statistical difference in endograft deployment success between groups (2D angiography, eight of nine patients [89%]; 3D angiography and IF, 14 of 14 patients each [100%]). The IF group showed significant reduction (P < .0001) in injected contrast medium volume versus other groups (2D, 235 mL ± 145; 3D, 225 mL ± 119; IF, 65 mL ± 28). Mean DAP values showed no significant difference between groups (2D, 1,188 Gy·cm² ± 1,067; 3D, 984 Gy·cm² ± 581; IF, 655 Gy·cm² ± 457; P = .18); nor did procedure times (2D, 233 min ± 123; 3D, 181 min ± 53; IF, 189 min ± 60; P = .59).ConclusionsThe use of IF-based roadmapping is a feasible technique for endovascular complex aneurysm repair associated with significant reduction of injected contrast agent volume and similar x-ray exposure and procedure time.     

Polydioxanone Biodegradable Stent Placement in a Canine Urethral Model: Analysis of Inflammatory Reaction and Biodegradation

PurposeTo investigate the inflammatory reaction and perform quantitative analysis of biodegradation after placement of a polydioxanone (PDO) biodegradable stent in a canine urethral model.Materials and MethodsPDO biodegradable stents were placed in the proximal and distal urethra of nine male mongrel dogs. The dogs were euthanized 4 weeks (group A; n = 3), 8 weeks (group B; n = 3), or 12 weeks (group C; n = 3) after stent placement. The luminal diameter of the stent-implanted urethra was assessed by follow-up retrograde urethrography, and histologic findings were obtained after the dogs were killed. Stents were removed after euthanasia, and their surface morphology and molecular weight were evaluated. Hematologic examination was performed to evaluate inflammatory reaction.ResultsStent placement was technically successful in all dogs. The average luminal diameter gradually decreased. The average number of epithelial layers (2.93 vs 4.42; P < .001), the average thickness of papillary projection (0.80 mm vs 1.28 mm; P < .001), and the average thickness of submucosal fibrosis (0.34 mm vs 0.49 mm ; P < .001) were significantly increased in group B versus group A. There were no significant differences between group B and group C. The average inflammatory cell infiltration did not differ significantly in the three groups. Molecular weight losses were 54% in group A and 84% in group B. In group C, PDO stents were completely decomposed.ConclusionsAn experimental study in a canine urethral model has demonstrated acceptable inflammatory reaction with gradually increasing granulation tissue but no luminal obstruction within 12 weeks.     

Microwave Ablation of Osteoid Osteomas Using Dynamic MR Imaging for Early Treatment Assessment: Preliminary Experience

PurposeTo evaluate the efficacy of microwave ablation for osteoid osteomas by using dynamic contrast-enhanced magnetic resonance (MR) imaging in early treatment assessment.Materials and MethodsTen patients (two female, eight male; mean age, 28 y; range, 16–47 y) presenting with osteoid osteomas were treated between June 2010 and December 2012 with the use of computed tomography (CT)–guided microwave ablation. Osteoid osteomas were found at the femoral neck (n = 4), tibia (n = 3), calcaneus (n = 1), navicular bone (n = 1), and dorsal rib (n = 1). Dynamic contrast-enhanced MR imaging at 3.0 T was performed 1 day before microwave ablation and again after ablation. The procedure was considered successful if the signal intensity (SI) of the lesion on MR imaging decreased by at least 50% and the patient was pain-free within 1 week of intervention.ResultsAll patients were pain-free within 1 week after microwave ablation and remained so during the 6 months of follow-up. No major or minor complications developed. On average, SI of the lesions decreased by 75% (range, 55.5%–89.1%) after treatment. The difference in lesion SI before versus after ablation was significant by t test (P < .0001; confidence interval, 120.26–174.96) and Wilcoxon test (P = .0020).ConclusionsMicrowave ablation treatment of osteoid osteoma was highly successful, without any complications observed. Dynamic contrast-enhanced MR imaging is a useful tool for diagnosing osteoid osteoma and evaluating treatment.     

Irreversible Electroporation of the Pig Kidney with Involvement of the Renal Pelvis: Technical Aspects,Clinical Outcome,and Three-dimensional CT Rendering for Assessment of the Treatment Zone

PurposeTo analyze irreversible electroporation (IRE) of the pig kidney with involvement of the renal pelvis.Materials and MethodsIRE of renal tissue including the pelvis was performed in 10 kidneys in five pigs. Three study groups were defined: group I (two applicators with parallel configuration; n = 11), group II (three applicators with triangular configuration; n = 2), and group III (six applicators with complex configuration; n = 3). After IRE and before euthanasia, pigs underwent contrast-enhanced computed tomography (CT). Technical aspects (radial distance of applicators, resulting mean current), clinical outcome (complications, blood samples), and three-dimensional CT rendering for assessment of the treatment zone (short axis, circularity) were assessed.ResultsRadial distances of applicators were 14.3 mm ± 2.8 in group I, 12.3 mm ± 1.9 in group II, and 16.4 mm ± 3.5 in group III. Resulting mean currents were 25.7 A ± 6.5 in group I, 27.0 A ± 7.1 in group II, and 39.4 A ± 8.9 in group III. In group III, two perirenal hematomas were identified. There was no damage to the renal pelvis. During IRE, clinical blood parameters and cardiovascular markers did not change significantly. Short axis measurements were 20.6 mm ± 3.6 in group I, 31.9 mm ± 8.2 in group II, and 39.3 mm ± 2.4 in group III (P < .01 between groups). Circularity scores were 0.8 ± 0.2 in group I, 0.7 ± 0.1 in group II, and 0.7 ± 0.1 in group III, with a score of 1 indicating perfect roundness (P value not significant).ConclusionsIRE of the pig kidney with involvement of the renal pelvis is feasible and safe. Size but not shape of the treatment zone is significantly affected by applicator configuration.     

Respiration-induced Deformations of the Superior Mesenteric and Renal Arteries in Patients with Abdominal Aortic Aneurysms

PurposeTo quantify respiration-induced deformations of the superior mesenteric artery (SMA), left renal artery (LRA), and right renal artery (RRA) in patients with small abdominal aortic aneurysms (AAAs).Materials and MethodsSixteen men with AAAs (age 73 y ± 7) were imaged with contrast-enhanced magnetic resonance angiography during inspiratory and expiratory breath-holds. Centerline paths of the aorta and visceral arteries were acquired by geometric modeling and segmentation techniques. Vessel translations and changes in branching angle and curvature resulting from respiration were computed from centerline paths.ResultsWith expiration, the SMA, LRA, and RRA bifurcation points translated superiorly by 12.4 mm ± 9.5, 14.5 mm ± 8.8, and 12.7 mm ± 6.4 (P < .001), and posteriorly by 2.2 mm ± 2.7, 4.9 mm ± 4.2, and 5.6 mm ± 3.9 (P < .05), respectively, and the SMA translated rightward by 3.9 mm ± 4.9 (P < .01). With expiration, the SMA, LRA, and RRA angled upward by 9.7° ± 6.4, 7.5° ± 7.8, and 4.9° ± 5.3, respectively (P < .005). With expiration, mean curvature increased by 0.02 mm^?1 ± 0.01, 0.01 mm^?1 ± 0.01, and 0.01 mm^?1 ± 0.01 in the SMA, LRA, and RRA, respectively (P < .05). For inspiration and expiration, RRA curvature was greater than in other vessels (P < .025).ConclusionsWith expiration, the SMA, LRA, and RRA translated superiorly and posteriorly as a result of diaphragmatic motion, inducing upward angling of vessel branches and increased curvature. In addition, the SMA exhibited rightward translation with expiration. The RRA was significantly more tortuous, but deformed less than the other vessels during respiration.     

Localized Hyperthermia with Iron Oxide–Doped Yttrium Microparticles: Steps toward Image-Guided Thermoradiotherapy in Liver Cancer

PurposeTo test whether iron oxide (IO)–containing yttrium aluminosilicate (YAS) microparticles (MPs) can generate localized therapeutic hyperthermia (≥ 43°C) when injected intratumorally in an animal model of liver cancer and whether MP distributions could be visualized with magnetic resonance (MR) imaging.Materials and MethodsTwenty-one Sprague–Dawley rats implanted with N1-S1 liver tumors were assigned to alternating magnetic field (AMF) exposure following intratumoral injection with IO-YAS MPs (n = 7), sham surgery (n = 7), or baseline iron quantification (n = 7). Three fiberoptic probes allowed spatial and temporal monitoring of temperatures during 24 minutes of AMF exposure. T2-weighted turbo spin-echo MR imaging was performed within 1 hour after the procedure to detect signal voids caused by IO-YAS deposition. Hematoxylin and eosin–stained pathologic slides were also obtained, and the presence of IO-YAS was evaluated with inductively coupled plasma optical emission spectroscopy.ResultsFollowing AMF exposure, intratumoral temperatures after IO-YAS MP injection achieved therapeutic hyperthermia whereas those after sham surgery did not (46.6°C ± 1.3 vs 36.8°C ± 0.4; P < .0001). Within the treated group, the normal hepatic parenchyma (NHP) and rectal temperatures were 37.4°C ± 0.9 and 36.5°C ± 1.0 (P = .0809) at the conclusion of AMF exposure, respectively. A T2-weighted signal void at the tumor site was observed in all seven treated animals, and intratumoral IO-YAS was visualized on subsequent histopathologic examination in each case. The mean ratio of tumor:NHP Fe concentrations attributable to IO-YAS MPs was 108:1.ConclusionsAMF exposure of intratumoral IO-YAS MPs generates localized therapeutic hyperthermia in an animal model of liver cancer. MR detectability and potential for combination brachytherapy warrants further investigation for thermoradiotherapy in liver cancer.     

Comparison of Simulation-based Treatment Planning with Imaging and Pathology Outcomes for Percutaneous CT-guided Irreversible Electroporation of the Porcine Pancreas: A Pilot Study

PurposeTo investigate the reliability of simulations for planning pancreatic irreversible electroporation (IRE) ablations compared with computed tomography (CT) and pathology outcomes in an animal model.Materials and MethodsSimulations were performed varying treatment parameters, including field strength (1.5–2.5 kV/cm), pulse number (70–90 pulses), and pulse length (70–100 µs). Pancreatic IRE was performed in six pigs under CT guidance. Two animals each were sacrificed for histology after 1 day, 14 days, and 28 days. Follow-up CT scans were performed on day 0, day 1, day 14, and day 28. Biochemical markers were collected before the procedure, 1 day after the procedure, and 14 days after the procedure.ResultsAll ablation zones could be visualized on CT scan immediately after the procedure and on day 1 follow-up CT scan, and all animals survived until the designated endpoints. Histopathology revealed necrosis and edema on day 1 and fibrosis and glandular atrophy after 28 days. Blood vessels close to the ablation zone appeared normal. Laboratory analysis indicated mild to moderate amylasemia and lipasemia with normalization after 14 days. The ablation size on CT scan measured a mean (± SD) 146% ± 18 (day 0, P < .126) and 168% ± 18 (day 1, P < .026) of the simulation and on pathology measured 119% ± 10 (day 1, not significant) of the simulation.ConclusionsResults from simulations for planning IRE ablations, CT, and pathology may differ from each other. Ablation zones on CT and pathology appear larger than simulated, suggesting that clinically used treatment planning may underestimate the ablation size in the pancreas.     

Early Results from a United States Trial of Prostatic Artery Embolization in the Treatment of Benign Prostatic Hyperplasia

PurposeTo report early findings from a prospective United States clinical trial to evaluate the efficacy and safety of prostatic artery embolization (PAE) for benign prostatic hyperplasia (BPH).Materials and MethodsFrom January 2012 to March 2013, 72 patients were screened and 20 patients underwent treatment. Patients were evaluated at baseline and selected intervals (1, 3, and 6 mo) for the following efficacy variables: American Urological Association (AUA) symptom score, quality of life (QOL)–related symptoms, International Index of Erectile Function score, peak urine flow rate, and prostate volume (on magnetic resonance imaging at 6 mo). Complications were monitored and reported per Society of Interventional Radiology guidelines.ResultsEmbolization was technically successful in 18 of 20 patients (90%); bilateral PAE was successful in 18 of 19 (95%). Unsuccessful embolizations were secondary to atherosclerotic occlusion of prostatic arteries. Clinical success was seen in 95% of patients (19 of 20) at 1 month, with average AUA symptom score improvements of 10.8 points at 1 month (P < .0001), 12.1 points at 3 months (P = .0003), and 9.8 points at 6 months (P = .06). QOL improved at 1 month (1.9 points; P = .0002), 3 months (1.9 points; P = .003), and 6 months (2.6 points; P = .007). Sexual function improved by 34% at 1 month (P = .11), 5% at 3 months (P = .72), and 16% at 6 months (P = .19). Prostate volume at 6 months had decreased 18% (n = 5; P = .05). No minor or major complications were reported.ConclusionsEarly results from this clinical trial indicate that PAE offers a safe and efficacious treatment option for men with BPH.