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.     

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.     

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.     

Microwave Thermal Ablation of Spinal Metastatic Bone Tumors

PurposeTo assess feasibility, safety, and efficacy of microwave ablation of spinal metastatic bone tumors.Materials and MethodsRetrospective study of 17 patients with 20 spinal metastatic tumors treated with microwave ablation under computed tomographic guidance between March 2011 and August 2013 was performed. Ablations were performed under local anesthesia and nitrous oxide ventilation. Lesions were lumbar (n = 10), sacral (n = 7), and thoracic (n = 3) in location. Primary neoplastic sites were lung (n = 9), prostate (n = 4), kidney (n = 6), and uterus (n = 1). Adjunct cementoplasty was performed in nine cases, and a temperature-monitoring device was used in four cases. Procedure effectiveness was evaluated by visual analog scale (VAS) during a 6-month follow-up. Patient medical records were reviewed, and demographic and clinical data, tumor characteristics, and information on pain were assessed.ResultsMean ablation time was 4.4 minutes ± 2.7 (range, 1–8 min), with an average of 3.8 cycles per ablation at 60 W (range, 30–70 W). The preprocedure mean VAS score was 7.4 ± 1.2 (range, 6–9). Pain relief was achieved in all but one patient. Follow-up VAS scores were as follows: day 0, 1.3 ± 1.8 (P < .001); day 7, 1.6 ± 1.7 (P < .001); month 1, 1.9 ± 1.6 (P < .001); month 3, 2.2 ± 1.5 (P < .001); and month 6, 2.3 ± 1.4 (P < .01). No complications were noted.ConclusionsMicrowave ablation appears to be feasible, safe, and an effective treatment of painful refractory spinal metastases and may be considered as a potential alternative percutaneous technique in the management of spinal metastases.     

Quantitative Assessment of Lipiodol Deposition after Chemoembolization: Comparison between Cone-Beam CT and Multidetector CT

PurposeTo evaluate the ability of cone-beam computed tomography (CBCT) performed directly after transarterial chemoembolization to assess ethiodized oil (Lipiodol) deposition in hepatocellular carcinoma (HCC) and compare it with unenhanced multidetector computed tomography (CT).Materials and MethodsConventional transarterial chemoembolization was used to treat 15 patients with HCC, and CBCT was performed to assess Lipiodol deposition directly after transarterial chemoembolization. Unenhanced multidetector CT was performed 24 hours after transarterial chemoembolization. Four patients were excluded because the margin of tumor or area of Lipiodol deposition was unclear. The image enhancement density of the entire tumor and liver parenchyma was measured by ImageJ software, and tumor-to-liver contrast (TLC) was calculated. In addition, volumetric measurement of tumor and Lipiodol was performed by semiautomatic three-dimensional volume segmentation and compared using linear regression to evaluate consistency between the two imaging modalities.ResultsThe mean value of TLC on CBCT was not significantly different from TLC on multidetector CT (337.7 HU ± 233.5 vs 283.0 HU ± 152.1, P = .103).The average volume of the whole tumor and of only the regions with Lipiodol deposition and the calculated average percentage of Lipiodol retention on CBCT were not significantly different compared with multidetector CT (tumor volume, 9.6 cm³ ± 11.8 vs 10.8 cm³ ± 14.2, P = .142; Lipiodol volume, 6.3 cm³ ± 7.7 vs 7.0 cm³ ± 8.1, P = .214; percentage of Lipiodol retention, 68.9% ± 24.0% vs 72.2% ± 23.1%, P = .578). Additionally, there was a high correlation in the volume of tumor and Lipiodol between CBCT and multidetector CT (R² = 0.919 and 0.903).ConclusionsThe quantitative image enhancement and volume analyses demonstrate that CBCT is similar to multidetector CT in assessing Lipiodol deposition in HCC after transarterial chemoembolization.     

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.     

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.     

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.     

Percutaneous Microwave Ablation of Hepatic Tumors: Prospective Evaluation of Postablation Syndrome and Postprocedural Pain

PurposeTo prospectively investigate the frequency and severity of postablation syndrome (PAS) and postprocedural pain in a cohort of patients undergoing hepatic microwave ablation.Materials and MethodsFrom March 2009 to November 2011, 54 consecutive patients undergoing microwave ablation for liver tumors were enrolled. A questionnaire was administered to investigate PAS and pain at 1, 7, and 40 days after ablation. Four patients did not complete all three questionnaires and were excluded from the analysis. Additionally, laboratory tests with results known to significantly increase or decrease after ablation were performed, and ablation parameters were recorded. Potential predictors of PAS and pain at 1 and 7 days were evaluated by a logistic regression model.ResultsFifty patients underwent a single microwave ablation session, 33 for hepatocellular carcinoma (HCC) and 17 for liver metastasis. Median ablation volumes on computed tomography were 31 cm³ for HCC and 42 cm³ for metastasis. Sixty percent of patients experienced PAS in the first week. Aspartate aminotransferase (AST) levels after ablation were significantly associated with PAS during postprocedure days 1–7. Median visual analog scale scores for pain at the puncture site were 1 and 0.24 at 1 and 7 days, respectively. The risk of having at least moderate pain in the first week was significantly related to ablation volume and time and postablation increase in AST level.ConclusionsThe incidence and severity of PAS with hepatic microwave ablation is similar to that reported for radiofrequency ablation, with the best predictive factor being postablation AST level elevation. Postablation pain was best predicted by total ablation volume and AST level.     

Inhibition of Growth in a Rabbit VX2 Thigh Tumor Model with Intraarterial Infusion of Carbon Dioxide–Saturated Solution

PurposeTo evaluate the efficacy of intraarterial infusion of CO₂-saturated solution in rabbit VX2 thigh tumors.Materials and MethodsFourteen Japanese white rabbits had VX2 tumors implanted in the right femoral muscle 3 weeks before intraarterial infusion. Rabbits were divided into control and CO₂ groups (n = 7 each). Fifty milliliters of solution (saline solution and CO₂-saturated solution for the control and CO₂ groups, respectively) was administered via a 24-gauge catheter in the ipsilateral iliac artery close to the feeding artery of the VX2 tumor. All rabbits were killed for tumor harvest on day 3 after the procedure. Tumor volume was evaluated with in vivo direct caliper measurement and contrast-enhanced computed tomography (CT). Tumor apoptotic changes were examined by DNA fragmentation assay and immunoblot analysis. The tumor growth ratio and apoptotic cell rate were analyzed.ResultsBody weight was equally increased in both groups, but the mean tumor growth ratio was significantly decreased in the CO₂ group compared with the control group (−9.5% ± 7.9 vs 27.2% ± 6.6 and 4.1% ± 4.4 vs 35.7% ± 4.5 measured by calipers and contrast-enhanced CT, respectively; P < .01). Apoptotic activity in the CO₂ group was higher than in the control group (number of apoptotic cells per area, 215.0 ± 58.7 vs 21.8 ± 5.4; adjusted relative density of cleaved caspase-3, 0.23 ± 0.07 vs 0.04 ± 0.01; P < .01).ConclusionsIntraarterial infusion of CO₂-saturated solution inhibits rabbit VX2 thigh tumor growth by activation of apoptotic cell death through cleaved caspase-3 upregulation.     

A Novel Resorbable Embolization Microsphere for Transient Uterine Artery Occlusion: A Comparative Study with Trisacryl-Gelatin Microspheres in the Sheep Model

PurposeTo evaluate angiographic recanalization, inflammatory reaction, and uterine damage after sheep uterine artery embolization (UAE) with a novel calibrated resorbable embolization microsphere (REM) and compare the results with control nonresorbable microspheres.Materials and MethodsSix hormonally artificially cycled sheep underwent bilateral UAE until stasis with either REM or trisacryl-gelatin microspheres (TGMS). At 7 days, control angiograms were obtained to assess the residual vascularization at arterial and parenchymal phases. The animals were then sacrificed for analysis of the presence of microspheres, inflammatory foreign body reaction, and surface areas of uterine damage.ResultsMean volume of microspheres injected per uterine artery (UA) or per animal did not differ between groups. At day 7, the flow was normal for six of six UAs that received embolization with REM versus only three of six UAs with TGMS (P = .0455, χ² test). Uterine parenchymography showed no defects in six UAs in the REM group versus five defects in six UAs in the TGMS group (P = .0060, χ² test). No REM or residual fragments of microspheres were observed on histologic analysis. TGMS were observed in tissues and accompanied by a mild inflammatory response. Necrosis rates were not significantly different between the two products, either in endometrium (REM 23.5% ± 28.8% [median 8.1%] vs TGMS 21.8% ± 23.7% [median 14.6%]) or in myometrium (REM 8.2% ± 22.7% [median 0.0%] vs TGMS 8.8% ± 20.8% [median 0.9%]). Endometrium alteration rate was lower with REM than with TGMS (39.7% ± 25.7% [median 34%] vs 60.6% ± 27.1% [median 71%]; P = .0060, Mann-Whitney test). Myometrium alteration rates were not significantly different between REM (45.7% ± 37.1% [median 63.0%]) and TGMS (37.8% ± 34.0% [median 19.1%]).ConclusionsAt 1 week after sheep UAE with REM, the recanalization was complete, the microspheres were completely degraded, and there was no remnant inflammatory response.     

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.     

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.     

Planning US for Percutaneous Radiofrequency Ablation of Small Hepatocellular Carcinomas (1–3 cm): Value of Fusion Imaging with Conventional US and CT/MR Images

PurposeTo assess whether fusion of conventional ultrasonography (US) with liver computed tomography/magnetic resonance images for planning US for percutaneous radiofrequency (RF) ablation can reduce false-positive detection and enhance lesion detectability of small hepatocellular carcinomas (HCCs) on conventional US.Materials and MethodsThis retrospective study was approved by the institutional review board, and informed consent was waived. A total of 137 patients with single HCCs (mean ± standard deviation, 1.7 ± 0.6 cm; range, 1.1–3.0 cm) were included. Planning US was performed by two radiologists by using conventional US first and fusion imaging later in the same session. The false-positive detection rate of conventional US was assessed with the results of fusion imaging used as a reference standard. True-positive detection rates on conventional US and fusion imaging were compared by McNemar test. Initially undetectable HCCs on conventional US that became detectable after image fusion were also assessed.ResultsThe false-positive detection rate of conventional US was 7.7% (nine of 117). Overall true-positive detection rates on conventional US and fusion imaging were 78.8% (108 of 137) and 90.5% (124 of 137), respectively (P = .0002); the rates were significantly different between conventional US and fusion imaging for HCCs smaller than 2.0 cm, but not for HCCs 2.0 cm or larger. Of 20 initially undetectable HCCs on conventional US, nine (45.0%) became detectable after image fusion.ConclusionsFusion imaging for planning US for percutaneous RF ablation can reduce false-positive detection and enhance lesion detectability of small HCCs on conventional US.     

Outcomes of Percutaneous Interventions in Transposed Hemodialysis Fistulas Compared with Nontransposed Fistulas and Grafts

PurposeTo compare postpercutaneous intervention outcomes of autogenous venous-transposition arteriovenous fistulas (AVFs) versus those of autogenous nontransposed AVFs (nAVFs) and prosthetic arteriovenous grafts (AVGs).Materials and MethodsA total of 591 hemodialysis accesses (195 transposed AVFs [tAVFs], 205 nAVFs, 191 AVGs) in 522 patients (278 male; mean age, 57 y; range, 15–91 y) underwent percutaneous transluminal angioplasty (PTA) and/or mechanical thrombectomy (ie, declotting). Access characteristics, surgical history, percutaneous interventions, postinterventional primary and secondary access patency, and follow-up data were collected. Cox proportional-hazards regression analyses, Fisher exact tests, and χ² tests were performed.ResultsMean follow-up period was 32 months. Mean access ages at initial percutaneous intervention were 260 days (tAVF), 206 days (nAVF), and 176 days (AVG; P < .01). One-year postinterventional primary patency (PIPP) rates were 25% (tAVF), 24% (nAVF), and 14% (AVG). One-year postinterventional secondary patency (PISP) rates were 77% (tAVF), 61% (nAVF), and 63% (AVG). Median PIPP durations were 138 days (tAVF), 121 days (nAVF), and 79 days (AVG; P = .0001). Median PISP durations were 1,076 days (tAVF), 783 days (nAVF), and 750 days (AVG; P = .019). Total interventions needed to maintain PISP were 2.4 (tAVF), 1.3 (nAVF), and 3.2 (AVG) per patient-year (P < .001), which included 1.9, 1.2, and 1.4 PTAs (P < .01) and 0.45, 0.15, and 1.8 declotting procedures, respectively (P < .001).ConclusionsBased on the number of percutaneous interventions needed to maintain PISP, these results confirm the current Dialysis Outcomes Quality Initiative access preference of nAVFs before tAVFs before AVGs. tAVFs offered superior postinterventional outcomes than AVGs. With additional interventions, tAVFs could even outperform nAVFs in terms of PISP.     

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.     

Evaluation of an Endorectal Electrode for Performing Focused Irreversible Electroporation Ablations in the Swine Rectum

PurposeTo study the feasibility of a novel endorectal electrode for the creation of focal ablations of the rectal wall with the use of irreversible electroporation (IRE).Materials and MethodsA monopolar electrode with a grounding pad (10 ablations in five pigs) and a bipolar electrode (two ablations in one pig) were evaluated in healthy swine rectum. A two-dimensional model of the electrode in the rectum was created and used to solve the Laplace equation to determine field strength. Simulation was used to identify treatment settings for superficial ablation (mucosal layers) or transmural ablation of rectal wall. Animals were euthanized within 4 hours after treatment.ResultsTreatment was successfully completed without treatment-related complications. Eleven of 12 lesions were successfully located and extracted for pathologic analysis. All lesions were characterized by necrotic cell death with mild inflammation and hyperemia, with a sharp demarcation between ablated and adjacent normal tissue. Depth of lesions corresponded with numeric simulation. Histologic analysis and measurements indicated that lesion creation with the superficial treatment setting resulted in ablation of mucosal and submucosal layers with superficial or no injury to the muscularis propria (9.97 mm ± 0.31 length, 3.3 mm ± 2.92 depth), and that lesion creation with the transmural treatment setting resulted in full-thickness ablation (12.43 mm ± 3.85 length, 4.97 mm ± 2.89 depth) of the rectal wall.ConclusionsAn endorectal electrode can be used to deliver IRE and create limited focal ablations in the rectal wall. Treatment parameters can be determined through numeric modeling to control the depth of penetration of ablation.     

Microwave Ablation of Pancreatic Head Cancer: Safety and Efficacy

PurposeTo evaluate the safety and efficacy of percutaneous microwave (MW) ablation treatment in locally advanced, nonresectable, nonmetastatic pancreatic head cancer.Materials and MethodsTen patients with pancreatic head cancer treated with percutaneous (n = 5) or laparotomic (n = 5) MW ablation were retrospectively reviewed. The MW generator used (45 W at 915 MHz) was connected by coaxial cable to 14-gauge straight MW antennas with a 3.7- or 2-cm radiating section. One or two antennae were used, with an ablation time of 10 minutes. Ultrasonographic (US) and combined US/cone-beam computed tomographic (CT) guidance were used in five patients each. Follow-up was performed by CT after 1, 3, 6, and, when possible, 12 months. Tumor response was assessed per Response Evaluation Criteria In Solid Tumors (version 1.1) and Choi criteria. The feasibility, safety, and major and minor complications associated with quality of life (QOL) were recorded prospectively.ResultsThe procedure was feasible in all patients (100%). One late major complication was observed in one patient, and no visceral injury was detected. No patient had further surgery, and all minor complications resolved during the hospital stay. An improvement in QOL was observed in all patients despite a tendency to return to preoperative levels in the months following the procedure, without the influence of minor complications. No repeat treatment was performed.ConclusionsDespite the small number of patients, the present results can be considered encouraging, showing that MW ablation is a feasible approach in the palliative treatment of pancreatic tumors.     

Embolization of Angiographically Visible Type I and II Utero-ovarian Anastomoses during Uterine Artery Embolization for Fibroid Tumors: Impact on Symptom Recurrence and Permanent Amenorrhea

PurposeTo compare the incidences of symptom recurrence and permanent amenorrhea following uterine artery embolization (UAE) for symptomatic fibroid tumors in patients with type I and II utero-ovarian anastomoses (UOAs) with versus without ovarian artery embolization (OAE).Materials and MethodsA retrospective, institutional review board–approved study of 99 women who underwent UAE for symptomatic fibroid tumors from April 2005 to October 2010 was conducted to identify patients who had type I or II UOAs at the time of UAE. Based on the embolization technique, patients were categorized into standard (ie, UAE only), combined (ie, UAE and OAE), and control (patients without UOAs who underwent UAE) groups. Data collected included patient characteristics, procedural technique and findings, symptom recurrence, secondary interventions, and permanent amenorrhea. Statistical analysis was performed with the Fisher exact test, with significance reached at P < .05.ResultsTwenty patients (20.2%; mean age, 46.9 y ± 6.3) had type I (n = 3) or II (n = 17) UOAs. Thirteen (65%) underwent UAE only (standard group) and seven (35%) underwent UAE and OAE (combined group). There were no significant differences between groups in demographics or in the incidence of permanent amenorrhea after procedures (follow-up, 561 d ± 490). There was a significantly higher incidence of symptom recurrence in the standard group compared with the control group (P = .01), with no differences between combined and control groups (P = 1).ConclusionsThere were no statistical differences in permanent amenorrhea rates in the groups studied, with significantly higher symptom recurrence rates observed when OAE was not performed in the setting of UOA.     

Long-term Outcomes of Coil Packing for Visceral Aneurysms: Correlation between Packing Density and Incidence of Coil Compaction or Recanalization

PurposeTo evaluate the correlation between packing density and the incidence of coil compaction or recanalization of visceral artery aneurysms (VAAs) after coil packing.Materials and MethodsBetween July 2004 and April 2012, coil packing was performed for 46 true visceral aneurysms (16 splenic, 11 pancreaticoduodenal, eight renal, six hepatic, three superior mesenteric, one right gastric, and one gastroepiploic) in 42 patients. The size and volume of the aneurysm, packing density, and the incidences of compaction and recanalization were evaluated retrospectively.ResultsThe mean follow-up period was 37 months ± 8 (range, 11–80 mo). The mean packing density was 19% ± 8 (range, 5%–42%), mean aneurysm size was 19 mm ± 8 (range, 5–40 mm), and mean volume was 4,108 mm³ ± 5,435 (range, 72–26,235 mm³). Compaction and recanalization occurred in two (4%) and 12 aneurysms (26%), respectively. The mean packing density was significantly lower in aneurysms with compaction or recanalization than in unaffected aneurysms (12% vs 22%; P = .00014). There was a significant difference in mean packing density between small (< 20 mm; 22%) and large (≥ 20 mm) aneurysms (15%; P = .0045). The mean size and volume were significantly larger for coil-compacted or recanalized aneurysms than for unaffected aneurysms (P < .05). In aneurysms with a packing density of at least 24%, no compaction or recanalization occurred.ConclusionsCoil compaction or recanalization after coil packing for VAAs more often occurs after insufficient embolization with low packing density and in patients with large aneurysms.