Radiofrequency Ablation of T1 Lung Carcinoma: Comparison of Outcomes for First Primary,Metachronous, and Synchronous Lung Tumors

PurposeTo report and compare outcomes after radiofrequency ablation for treatment-naïve first primary, metachronous, and synchronous T1 lung tumors.Materials and MethodsThis institutional review board–approved retrospective study reviewed 29 patients (12 men and 17 women; median age, 73 y; age range, 55–86 y) with treatment-naïve T1 lung tumors treated with radiofrequency ablation. Tumors in the 29 patients included 21 T1a and 8 T1b first primary (n = 11), metachronous (n = 14), or synchronous (n = 4) tumors (adenocarcinoma, n = 25; squamous cell carcinoma, n = 3; unspecified, n = 1). Median tumor diameter was 14 mm (range, 10–26 mm). Surveillance computed tomography or positron emission tomography–computed tomography was performed over a median period of 28 months (range, 12–83 mo). Technical success and effectiveness rates and overall and progression-free 1-year, 3-year, and 5-year survivals were calculated according to stage, first primary, metachronous, and synchronous tumor status.ResultsTechnical success and effectiveness was 97%. Local control occurred in 17 of 21 T1a tumors (81%) and 5 of 8 T1b tumors (62.5%). The local progression rate of first primary tumors (5 of 11; 45%) was higher than that of metachronous (2 of 14; 14%; P = .07) and synchronous (0 of 4; P = .01) tumors. Estimated 1-year, 3-year, and 5-year local tumor progression-free survival was 79%, 75%, and 75%. Estimated 1-year, 3-year, and 5-year overall survival was 100%, 60%, and 14%. Survival outcomes were similar for patients with first primary, metachronous, or synchronous tumors.ConclusionsRadiofrequency ablation results in good local control and progression-free survival in patients with treatment-naïve T1 lung tumors, including patients with metachronous and synchronous tumors.     

Irreversible Electroporation for Nonthermal Tumor Ablation in the Clinical Setting: A Systematic Review of Safety and Efficacy

PurposeTo provide an overview of current clinical results of irreversible electroporation (IRE), a novel, nonthermal tumor ablation technique that uses electric pulses to induce cell death, while preserving structural integrity of bile ducts and vessels.MethodsAll in-human literature on IRE reporting safety or efficacy or both was included. All adverse events were recorded. Tumor response on follow-up imaging from 3 months onward was evaluated.ResultsIn 16 studies, 221 patients had 325 tumors treated in liver (n = 129), pancreas (n = 69), kidney (n = 14), lung (n = 6), lesser pelvis (n = 1), and lymph node (n = 2). No major adverse events during IRE were reported. IRE caused only minor complications in the liver; however, three major complications were reported in the pancreas (bile leak [n = 2], portal vein thrombosis [n = 1]). Complete response at 3 months was 67%–100% for hepatic tumors (93%–100% for tumors < 3 cm). Pancreatic IRE combined with surgery led to prolonged survival compared with control patients (20 mo vs 13 mo) and significant pain reduction.ConclusionsIn cases where other techniques are unsuitable, IRE is a promising modality for the ablation of tumors near bile ducts and blood vessels. This articles gives an extensive overview of the available evidence, which is limited in terms of quality and quantity. With the limitations of the evidence in mind, IRE of central liver tumors seems relatively safe without major complications, whereas complications after pancreatic IRE appear more severe. The available limited results for tumor control are generally good. Overall, the future of IRE for difficult-to-reach tumors appears promising.     

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.     

Contrast-enhanced US-guided Radiofrequency Ablation of Hepatocellular Carcinoma

PurposeContrast-enhanced ultrasound (US) has been shown to be an efficient imaging modality in guiding radiofrequency (RF) ablation of hepatocellular carcinomas (HCC). The purpose of the present study was to assess the usefulness of contrast-enhanced US in guiding RF ablation in patients with early-stage HCC that was not clearly visible on grayscale US or noncontrast computed tomography (CT).Materials and MethodsDuring a 17-month period, contrast-enhanced US–guided RF ablation was performed in 14 patients with 19 early-stage lesions that were poorly defined on grayscale US and noncontrast CT. Contrast-enhanced US was repeated after 30 minutes, and complete ablation was defined as absence of any arterial-phase enhancement within the ablated lesion. Patients were followed periodically with clinical evaluation, liver function tests, α-fetoprotein measurement, and multiphasic CT or magnetic resonance (MR) imaging for a minimum of 1 year after ablation to look for local recurrence or disease progression. Survival probability was estimated with the Kaplan–Meier method.ResultsComplete tumor ablation was achieved in all 19 lesions, with no evidence of residual or recurrent tumor in the ablated areas after a mean follow-up of 16 months. No major complications were observed in any patient. However, new lesions developed in other parts of the liver on follow-up scans in three patients, and were accordingly treated with RF ablation. Two patients died of disease progression or liver failure within the 1-year follow-up.ConclusionsFor early-stage HCCs not well visualized on unenhanced US or CT, contrast-enhanced US provides an additional tool to guide RF ablation.     

Contemporary Systematic Review and Meta-Analysis of Early Outcomes with Percutaneous Treatment for Infrapopliteal Atherosclerotic Disease

PurposeThe need for specialty devices to improve the technical outcome of endovascular interventions is dependent on the rate of early failure in such procedures. This meta-analysis assessed procedural outcomes of such interventions to elucidate the rate of early procedural failures and the need for such specialty devices.Materials and MethodsMEDLINE and EMBASE were searched for contemporary studies (2000–2012) reporting procedural or short-term outcomes for revascularization of infrapopliteal atherosclerotic lesions. A random-effects metaanalysis was performed, which included post hoc comparisons among treatment groups.ResultsA total of 42 studies with 52 treatment arms representing 3,660 unique patients were included. Technical success rates were higher with bare metal stents (BMSs; 98.6%) than with atherectomy (92.2%; P < .05) or percutaneous transluminal angioplasty (PTA; 91.2%; P = .01), and higher with drug-eluting stents (DESs) than with PTA (P < .001). DES use had higher primary patency rates than atherectomy (P < .05), BMS use (P < .001), and PTA (P < .01). The 30-day rate of target lesion revascularization was significantly higher with PTA (8.1%) than with BMSs (2.2%; P < .05) and DESs (1.1%; P < .05). Thirty-day rates of major unplanned amputation (range, 1.5%–4.4%) and mortality (range, 0.9%–3.3%) were comparable among treatment groups. Significant heterogeneity among studies was noted for most PTA outcomes. Publication bias was evident for most PTA and DES outcomes.ConclusionsEarly failure of percutaneous therapies in patients with infrapopliteal atherosclerotic lesions is device- and technique-dependent. Specialty devices designed to reduce technical failure rates may therefore be of benefit in this selected group of patients. Study results are confounded by inconsistent data reporting, heterogeneity of treatment effects, and publication bias.     

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.     

Risk Factors of Pneumothorax after CT-Guided Coaxial Cutting Needle Lung Biopsy through Aerated versus Nonaerated Lung

PurposeTo compare the risk factors of developing a pneumothorax after computed tomography–guided lung biopsy in cases in which aerated lung is traversed and in cases in which aerated lung is not traversed.Materials and MethodsThe records of 381 patients from July 2005–December 2009 were retrospectively reviewed. Multivariable analysis of patient demographic characteristics, lung lesion characteristics, and biopsy procedure details was performed with respect to the development of pneumothorax.ResultsAmong 381 patients, 249 biopsies traversed aerated lung tissue, and 132 biopsies did not traverse aerated lung tissue. Patients in whom aerated lung tissue was traversed had a significantly higher rate of pneumothorax. When aerated lung was not traversed, lesion size (≤ 2 cm vs > 2 cm; P = .025) and pleural-lesion angle (odds ratio = 1.033/degree; P = .004) were associated with pneumothorax. When aerated lung was traversed, location (middle vs upper; P = .009) and a transfissure approach (yes vs no; P = .001) were associated with pneumothorax.ConclusionsWhen aerated lung was not traversed, lesion size and pleural-lesion angle were associated with pneumothorax, and when aerated lung was traversed, location and a transfissure approach were associated with pneumothorax.     

Irreversible Electroporation Ablation of Malignant Hepatic Tumors: Subacute and Follow-up CT Appearance of Ablation Zones

PurposeTo describe findings on contrast-enhanced computed tomography (CT) images of malignant hepatic tumors 24–72 hours after percutaneous ablation by irreversible electroporation (IRE) and at midterm follow-up.Materials and MethodsRetrospective analysis of 52 malignant liver tumors—30 primary hepatic tumors and 22 hepatic metastases—in 34 patients (28 men and 6 women, mean age 64 y) treated by IRE ablation was performed. Ablation zones were evaluated by two examiners in a consensus reading by means of a dual-phase CT scan (consisting of a hepatic arterial and portal venous phase) performed 24–72 hours after IRE ablation and at follow-up.ResultsDuring the portal venous phase, ablation zones either were homogeneously hypoattenuating (n = 36) or contained heterogeneously isoattenuating or hyperattenuating (n = 16) foci, or both, in a hypoattenuating area. Of 52 lesions, 38 included gas pockets. Peripheral contrast enhancement of the ablation defect was evident in 23 tumors during the arterial phase and in 36 tumors during the portal venous phase. Four tumors showed intralesional abscesses after the intervention. At follow-up (mean, 4.7 mo), the mean volume of the ablation defects was reduced to 29% of their initial value.ConclusionsBecause normal findings on contrast-enhanced CT images after IRE ablation may be very similar to the typical characteristics of potential complications following ablation, such as liver abscesses, CT scans must be carefully analyzed to distinguish normal results after intervention from complications requiring further treatment.     

Surgical or Endovascular Therapy of Abdominal Penetrating Aortic Ulcers and Their Natural History: A Systematic Review

Little is known regarding the outcomes of endovascular and surgical treatment of penetrating ulcers in the abdominal aorta. The potential benefit of conservative management of asymptomatic disease is also debatable. A systematic review of the literature was undertaken to investigate these issues.     

No-touch Wedge Ablation Technique of Microwave Ablation for the Treatment of Subcapsular Tumors in the Liver

Ablation of exophytic and border-deforming liver tumors may increase risks of tumor seeding or hemorrhage. The present report describes a no-touch wedge ablation technique intended to potentially reduce tumor disruption while achieving technically adequate ablation. The technique involves the use of multiple probe positions tangential to the tumor, and was used to treat eight tumors. Complete ablation was demonstrated in all cases on early posttreatment imaging at an average of 16 days after the procedure. At an average imaging follow-up of 244 days, there was one case of local tumor recurrence. The technique may be useful for the ablation of exophytic, border-deforming liver tumors.     

Management of Type II Endoleak after Endovascular Repair of Arteriocaval Fistula Complicating Aortoiliac Aneurysm: Case Report and Literature Review

Endovascular treatment for arteriocaval fistula (ACF) has become the preferred alternative to open repair. However, endoleaks sometimes occur and maintain the ACF. A 64-year-old man presented with persistent fistula after placement of a bifurcated stent-graft for ACF complicating an aortoiliac aneurysm that was maintained by endoleaks from the inferior mesenteric and lumbar arteries. Transarterial embolization of the aneurysm sac and inferior mesenteric artery successfully resolved the problem without any complications observed over 16 months of follow-up. A literature review and discussion of the management options for this entity are presented. A combination of inflow and outflow control is important to obtain better long-term outcomes.     

Inferior Mesenteric Artery Collaterals to the Uterus during Uterine Artery Embolization: Prevalence,Risk Factors,and Clinical Outcomes

PurposeTo evaluate the prevalence of inferior mesenteric artery (IMA) collaterals to the uterus found during uterine artery embolization (UAE), associated risk factors, and clinical outcomes.Materials and MethodsThe records of 559 women who underwent UAE during the period 2008–2011 for uterine fibroids or adenomyosis found on magnetic resonance imaging were retrospectively analyzed. If IMA collaterals to the uterus were suspected on aortography performed after embolization, selective angiography was performed. Risk factors for IMA collaterals to the uterus were analyzed, including the presence of adenomyosis, baseline uterine volume, or prior pelvic surgery.ResultsCollaterals to the uterus were found from the ovarian artery (n = 21; 3.8%), IMA (n = 7; 1.3%), round ligament artery (n = 1; 0.2%), and internal pudendal artery (n = 1; 0.2%). IMA collaterals were found in seven patients. Of 185 patients, 6 (3.2%) had adenomyosis, with or without fibroids, which was significantly more frequent than the 1 (0.27%) of 374 patients who had fibroids only (P = .006). On multiple logistic regression analysis, the presence of adenomyosis (odds ratio, 19.556; P = .0168) and uterine volume (odds ratio, 1.003; P = .0069) were independent factors for the presence of IMA collaterals. Of the seven patients with IMA collaterals, embolization was not attempted in six, resulting in clinical failure in four. One patient who underwent IMA embolization with coils experienced clinical improvement.ConclusionsThe IMA was the second most common (1.3%) source of collaterals to the uterus. IMA collaterals were more frequent in patients with adenomyosis than in patients with fibroids only, resulting in high frequency of treatment failure.     

Histopathologic Comparison of Monopolar versus No-Touch Multipolar Radiofrequency Ablation to Treat Hepatocellular Carcinoma within Milan Criteria

PurposeTo compare histopathologically the completeness of radiofrequency (RF) ablation to treat hepatocellular carcinoma (HCC) with monopolar or multipolar technique.Materials and MethodsThirty-five consecutive patients (mean age, 59 y) with cirrhosis and HCC (n = 59) within Milan criteria received RF ablation and subsequently underwent liver transplantation (LT) for tumor progression or liver failure. Data were extracted retrospectively from a prospective database. Thirty nodules were treated with a monopolar device with internally cooled (n = 17) or perfused (n = 13) electrodes, and 29 were treated with a multipolar technique with internally cooled electrodes based on the “no-touch” concept. This consisted of inserting two or three straight electrodes around the nodule to avoid intratumor puncture to the greatest extent possible. Effectiveness of the three devices was compared by histopathologic examination of explants. Fisher exact and χ² tests and multivariate logistic regression analysis were performed.ResultsMean sizes of nodules ablated (25, 22, and 21.6 mm) and median times from ablation to LT (11, 7.5, and 8.4 months) for patients treated with the monopolar internally cooled electrode device (MoICD), monopolar perfused electrode device (MoPED), and multipolar internally cooled electrode device (MuICD), respectively, were similar (P = .8 and P = .9, respectively). Pathologic examination showed complete necrosis for eight of 17 and six of 13 nodules treated with the MoICD and MoPED, respectively, versus 26 of 29 treated with the MuICD (P = .0019). In multivariate analysis, RF technique remained the predictive factor for complete necrosis (P = .005).ConclusionsAblation of small HCCs with multipolar RF ablation based on the no-touch concept improves the rate of complete necrosis during pathologic examination compared with monopolar techniques.     

High-Frequency Jet Ventilation under General Anesthesia Facilitates CT-Guided Lung Tumor Thermal Ablation Compared with Normal Respiration under Conscious Analgesic Sedation

PurposeTo determine whether technical difficulty of computed tomography (CT)–guided percutaneous lung tumor thermal ablations is altered with the use of high-frequency jet ventilation (HFJV) under general anesthesia (GA) compared with procedures performed with normal respiration (NR) under conscious sedation (CS).Materials and MethodsThermal ablation treatment sessions performed with NR under CS or HFJV under GA with available anesthesia records and CT fluoroscopic images were retrospectively reviewed; 13 and 33 treatment sessions, respectively, were identified. One anesthesiologist determined the choice of anesthesiologic technique independently. Surrogate measures of procedure technical difficulty—time duration, number of CT fluoroscopic acquisitions, and radiation dose required for applicator placement for each tumor—were compared between anesthesiologic techniques. The anesthesiologist time and complications were also compared. Parametric and nonparametric data were compared by Student independent-samples t test and χ² test, respectively.ResultsPatients treated with HFJV under GA had higher American Society of Anesthesiologists classifications (mean, 2.66 vs 2.23; P = .009) and smaller lung tumors (16.09 mm vs 27.38 mm; P = .001). The time duration (220.30 s vs 393.94 s; P = .008), number of CT fluoroscopic acquisitions (10.31 vs 19.13; P = .023), and radiation dose (60.22 mGy·cm vs 127.68 mGy·cm; P = .012) required for applicator placement were significantly lower in treatment sessions performed with HFJV under GA. There was no significant differences in anesthesiologist time (P = .20), rate of pneumothorax (P = .62), or number of pneumothoraces requiring active treatment (P = .19).ConclusionsHFJV under GA appears to reduce technical difficulty of CT-guided percutaneous applicator placement for lung tumor thermal ablations, with similar complication rates compared with treatment sessions performed with NR under CS. The technique is safe and may facilitate treatment of technically challenging tumors.     

A Single-Institution Experience in Image-Guided Thermal Ablation of Adrenal Gland Metastases

PurposeTo assess safety, technical success, local control, and survival associated with percutaneous image-guided adrenal ablation.Materials and MethodsAdult patients with adrenal metastases who underwent percutaneous image-guided adrenal ablation during the years 2003–2012 were identified. There were 32 patients with 37 adrenal tumors identified. Technical success, safety, local control, and survival were analyzed according to standard criteria.ResultsIn 32 patients (25 men and 7 women; mean age, 66 y; age range, 44–88 y) with 37 adrenal tumors, 35 ablation procedures were performed. One patient with an 8.2-cm tumor underwent planned cryoablation debulking fully anticipating untreated margins owing to close proximity of the pancreas (ie, the intent was to diminish tumor burden rather than a curative intervention). Of the 36 patients treated with curative intent, technical success was achieved in 35 (97%) tumors. Follow-up imaging was performed on 34 of 37 tumors (excluding patients with intentional debulking [n = 1], technical failure [n = 1], and absence of follow-up [n = 1]). Local recurrence developed in 3 (8.8%) of 34 tumors. Local tumor control was achieved in 31 lesions at a mean of 22.7 months of follow-up. Recurrence-free survival and overall survival at 36 months were 88% and 52%, respectively, with a median survival of 34.5 months. A Common Terminology Criteria for Adverse Events version 4 grade 3 or 4 complication was observed in three (8.6%) ablation procedures.ConclusionsImage-guided ablation is safe and effective for local control of metastatic adrenal tumors and provides a minimally invasive alternative to surgical resection in appropriately selected patients.     

Predictive Value of Pattern Classification 24 Hours after Radiofrequency Ablation of Liver Metastases on CT and Positron Emission Tomography/CT

PurposeTo assess a classification scheme for predicting local tumor progression (LTP) after radiofrequency (RF) ablation of liver metastases, using predefined patterns on contrast-enhanced computed tomography (CT) and positron emission tomography (PET) combined with CT (PET/CT) acquired 24 hours after RF ablation.Materials and MethodsThere were 45 metastases in 20 patients treated. After 24 hours, imaging of the ablation zones was performed with contrast-enhanced PET/CT. Three independent radiologists prospectively assessed contrast-enhanced CT and combined PET/CT images to identify three patterns: pattern I, no tissue enhancement or fluorodeoxyglucose uptake between the ablation zone and the liver parenchyma; pattern II, a rimlike pattern; and pattern III, a peripheral nodule. PET/CT images obtained after 8–10 weeks were evaluated for LTP. The patterns were analyzed for their sensitivity, specificity, positive predictive value, and negative predictive value for predicting LTP.ResultsPattern I was most frequently observed (81% for contrast-enhanced CT and 61% for PET/CT) as well as for ablation zones that showed LTP (52% and 37%, respectively). Conversely, pattern II was observed for tumors that were completely ablated (6% and 29%, respectively). Patterns II and III together had the highest sensitivity for predicting LTP (48% and 63%, respectively); pattern III had the highest specificity (94% and 95%, respectively). For nodular patterns, test characteristics were better for PET/CT compared with contrast-enhanced CT, but the difference was not significant. Nodular patterns > 1 cm achieved high positive predictive value (both 100%).ConclusionsInflammation and hyperemia can hinder interpretation on imaging 24 hours after RF ablation, especially on PET/CT. Nodular patterns around the ablation zone on early contrast-enhanced CT and PET/CT have a high predictive value for LTP and should be taken into account for disease management.     

Safety and Efficacy of Transcatheter Arterial Embolization for Lower Gastrointestinal Bleeding: A Single-center Experience with 112 Patients

PurposeTo assess the safety and efficacy of transcatheter arterial embolization for lower gastrointestinal bleeding (LGIB) and to determine the prognostic factors that affect clinical outcome.Materials and MethodsAll patients diagnosed with LGIB by angiography at a single institution from April 2006 to January 2013 were included in a retrospective study. The rates of technical success, early recurrent bleeding, major complications, clinical success, and in-hospital mortality for transcatheter arterial embolization were determined. The influence of possible prognostic factors on the outcome was analyzed.ResultsA total of 112 patients were included (36 with small-bowel LGIB, 36 with colon LGIB, and 40 with rectal LGIB). N-butyl cyanoacrylate (NBCA) was the embolic agent for 84 patients (75.0%), whereas gelatin sponge pledgets (n = 20), microcoils (n = 2), polyvinyl alcohol particles with adjunctive gelatin sponge pledgets (n = 1), and blood clots (n = 1) were used in the other patients. The technical success rate was 96.4%. For the entire group, the rates of early recurrent bleeding, major complications, clinical success, and in-hospital mortality were 17.4%, 4.6%, 74.5%, and 25.0%, respectively. These were 15.2%, 4.8%, 75.3%, and 26.2%, respectively, in the NBCA group. Hematologic malignancy, immobilization status, and coagulopathy were significant prognostic factors for clinical outcomes.ConclusionsTranscatheter arterial embolization is a safe and effective treatment for LGIB. NBCA could be used as a primary embolic agent for this procedure.     

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.     

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.