Transarterial Embolization of Simple Pulmonary Arteriovenous Malformations: Long-Term Outcomes of 0.018-Inch Coils versus Vascular Plugs.

PURPOSE: To compare the safety, effectiveness, and persistence rates of 0.018-inch coils with those of Amplatzer vascular plugs (AVPs; Abbott Vascular, Abbott Park, Illinois) for the treatment of pulmonary arteriovenous malformations (PAVMs) in response to a growing concern that 0.018-inch coil embolization would increase the long-term persistence rate. MATERIALS AND METHODS: This is a retrospective, single-center study of a database (2002-2020) of 633 PAVM embolizations. Complex PAVMs and those not embolized with 0.018-inch coils or plugs were excluded. PAVM embolization material was classified into 4 groups: (a) 0.018-inch nonfibered coils (NFCs), (b) 0.018-inch fibered coils (FCs), (c) NFCs and FCs, or (d) plugs. Persistence was defined as flow through the PAVM on digital subtraction angiography (DSA) or as <30% diameter reduction of the aneurysmal sac on unenhanced computed tomography (CT). Kaplan-Meier analysis and Cox regression were used to assess PAVM's persistence-free survival. RESULTS: A total of 312 PAVM embolizations with NFCs (43 PAVMs), FCs (127 PAVMs), NFCs and FCs (12 PAVMs), or plugs (130 PAVMs) in 109 patients (28% men; mean age = 49 years) were included. All PAVM embolizations were technically successful without any major adverse events. PAVM persistence-free survival rates at 10 years' follow-up were 40.8% versus 44.7% in the NFC and FC groups (P = .22) and 47.3% versus 81.0% in the 0.018-inch coil (NFC or FC) and plug groups (P < .0001), respectively. There were 0.43 (79/182) and 0.08 (10/130) re-embolization procedures per PAVM in the 0.018-inch coil and plug groups, respectively (P < .001). CONCLUSIONS: PAVM embolization with 0.018-inch coils was safe, but persistence rate with PAVM embolization was significantly higher than that with plugs, with no significant differences between FCs and NFCs.

Uterine Fibroid Embolization Survey in Canada: Challenges, Opportunities, and Differences in Practices Across the Country.

Purpose: To assess the current practices surrounding Uterine Fibroid Embolization (UFE) in Canada. Methods: An online survey was sent to Canadian Association for Interventional Radiology (CAIR) members. It included questions on symptoms prompting UFE, patient awareness, investigation, UFE settings, the number of UFE procedures, and post-UFE care. The findings were discussed at CAIR's 2023 annual meeting by an expert panel. Results: Out of 792 surveys sent, 87 were filled (11%). Menorrhagia is the most common indication for UFE (87%). Women's awareness of UFE as a treatment option for fibroids is viewed as poor or average by 94% of our survey respondents. Most respondents see patients in clinics (92%) before the procedure and evaluate fibroids with MRI pre-UFE (76%). There is variability in care post-UFE, with 33% of procedures being performed as day surgery while 67% lead to overnight stay. For pain management, intravenous analgesia (including patient-controlled analgesia) is used in 76% (63/83) of cases while 19% (16/83) of respondents mentioned using epidural analgesia. Finally, there is an even split between embolic agent used; non-spherical polyvinyl alcohol (50%) and spherical particles (50%). Conclusion: Respondents believe patients in Canada still have limited awareness of UFE. Interventional radiologists are increasingly involved in the entire patient care trajectory, overseeing pre-and post-procedure care and hospitalizing patients. For pain management after UFE, it is observed that while epidural analgesia has been demonstrated more effective than alternatives, it is not widely used as the primary method.

CT analysis of aortic calcifications to predict abdominal aortic aneurysm rupture.

BACKGROUND: Abdominal aortic aneurysm (AAA) rupture prediction based on sex and diameter could be improved. The goal was to assess whether aortic calcification distribution could better predict AAA rupture through machine learning and LASSO regression. METHODOLOGY: In this retrospective study, 80 patients treated for a ruptured AAA between January 2001 and August 2018 were matched with 80 non-ruptured patients based on maximal AAA diameter, age, and sex. Calcification volume and dispersion, morphologic, and clinical variables were compared between both groups using a univariable analysis with p = 0.05 and multivariable analysis through machine learning and LASSO regression. We used AUC for machine learning and odds ratios for regression to measure performance. RESULTS: Mean age of patients was 74.0 ± 8.4 years and 89% were men. AAA diameters were equivalent in both groups (80.9 ± 17.5 vs 79.0 ± 17.3 mm, p = 0.505). Ruptured aneurysms contained a smaller number of calcification aggregates (18.0 ± 17.9 vs 25.6 ± 18.9, p = 0.010) and were less likely to have a proximal neck (45.0% vs 76.3%, p < 0.001). In the machine learning analysis, 5 variables were associated to AAA rupture: proximal neck, antiplatelet use, calcification number, Euclidian distance between calcifications, and standard deviation of the Euclidian distance. A follow-up LASSO regression was concomitant with the findings of the machine learning analysis regarding calcification dispersion but discordant on calcification number. CONCLUSION: There might be more to AAA calcifications that what is known in the present literature. We need larger prospective studies to investigate if indeed, calcification dispersion affects rupture risk. CLINICAL RELEVANCE STATEMENT: Ruptured aneurysms are possibly more likely to have their calcification volume concentrated in a smaller geographical area. KEY POINTS: • Abdominal aortic aneurysm (AAA) rupture prediction based on sex and diameter could be improved. • For a given calcification volume, AAAs with well-distributed calcification clusters could be less likely to rupture. • A machine learning model including AAA calcifications better predicts rupture compared to a model based solely on maximal diameter and sex alone, although it might be prone to overfitting.

Negative In Vivo Results Despite Promising In Vitro Data With a Coated Compliant Electrospun Polyurethane Vascular Graft.

INTRODUCTION: There is a growing need for small-diameter (<6 mm) off-the-shelf synthetic vascular conduits for different surgical bypass procedures, with actual synthetic conduits showing unacceptable thrombosis rates. The goal of this study was to build vascular grafts with better compliance than standard synthetic conduits and with an inner layer stimulating endothelialization while remaining antithrombogenic. METHODS: Tubular vascular conduits made of a scaffold of polyurethane/polycaprolactone combined with a bioactive coating based on chondroitin sulfate (CS) were created using electrospinning and plasma polymerization. In vitro testing followed by a comparative in vivo trial in a sheep model as bilateral carotid bypasses was performed to assess the conduits' performance compared to the actual standard. RESULTS: In vitro, the novel small-diameter (5 mm) electrospun vascular grafts coated with chondroitin sulfate (CS) showed 10 times more compliance compared to commercial expanded polytetrafluoroethylene (ePTFE) conduits while maintaining adequate suturability, burst pressure profiles, and structural stability over time. The subsequent in vivo trial was terminated after electrospun vascular grafts coated with CS showed to be inferior compared to their expanded polytetrafluoroethylene counterparts. CONCLUSIONS: The inability of the experimental conduits to perform well in vivo despite promising in vitro results may be related to the low porosity of the grafts and the lack of rapid endothelialization despite the presence of the CS coating. Further research is warranted to explore ways to improve electrospun polyurethane/polycaprolactone scaffold in order to make it prone to transmural endothelialization while being resistant to strenuous conditions.

A Multinational, Single-Arm Pivotal Study Assessing the Performance of the SoundBite Crossing System for Peripheral Chronic Total Occlusions (The PROSPECTOR Study).

PURPOSE: This study aimed to demonstrate the efficacy and safety of the SoundBite Crossing System‒Peripheral (SCS-P) to facilitate crossing chronic total occlusions (CTOs) of infrainguinal arteries. MATERIALS AND METHODS: This clinical trial was approved by the Ethics Committees of all 4 participating centers and enrolled 52 patients with symptomatic de novo infrainguinal CTOs. Technical device success, the primary efficacy endpoint, was defined as the ability to facilitate the treatment of the target lesion by crossing a portion or the whole length of the CTO. Freedom from SCS-P-related major adverse events (MAEs) at 30 days after the procedure was the primary safety endpoint. RESULTS: The SCS-P met the primary efficacy and safety endpoints in 92.3% (48/52) and 100% (52/52) of subjects, respectively. Technical device success with postprocedural patency and freedom from SCS-P-related MAEs was achieved in 88.5% (46/52) of subjects. The mean CTO crossing time was 20.0 minutes ± 30.8, and the SCS-P was able to traverse the whole CTO and enter the distal true lumen without the need of any other device in 59.6% (31/52) of subjects. The mean Rutherford category and ankle-brachial index improvement at the 30-day follow-up was 2.4 ± 1.17 and 0.23 ± 0.22, respectively. CONCLUSIONS: The SCS-P demonstrated a satisfactory safety and performance profile to cross peripheral CTOs and enter the distal true lumen of infrainguinal CTOs.

Strain Ultrasound Elastography of Aneurysm Sac Content after Randomized Endoleak Embolization with Sclerosing vs. Non-sclerosing Chitosan-based Hydrogels in a Canine Model.

PURPOSE: To compare the mechanical properties of aneurysm content after endoleak embolization with a chitosan hydrogel (CH) with that with a chitosan hydrogel with sodium tetradecyl sulfate (CH-STS) using strain ultrasound elastography (SUE). MATERIALS AND METHODS: Bilateral common iliac artery type Ia endoleaks were created in 9 dogs. Per animal, 1 endoleak was randomized to blinded embolization with CH, and the other, with CH-STS. Brightness-mode ultrasound, Doppler ultrasound, SUE radiofrequency ultrasound, and computed tomography were performed for up to 6 months until sacrifice. Radiologic and histopathologic studies were coregistered to identify 3 regions of interest: the embolic agent, intraluminal thrombus (ILT), and aneurysm sac. SUE segmentations were performed by 2 blinded independent observers. The maximum axial strain (MAS) was the primary outcome. Statistical analysis was performed using the Fisher exact test, multivariable linear mixed-effects models, and intraclass correlation coefficients (ICCs). RESULTS: Residual endoleaks were identified in 7 of 9 (78%) and 4 of 9 (44%) aneurysms embolized with CH and CH-STS, respectively (P = .3348). CH-STS had a 66% lower MAS (P < .001) than CH. The ILT had a 37% lower MAS (P = .01) than CH and a 77% greater MAS (P = .079) than CH-STS. There was no significant difference in ILT between treatments. The aneurysm sacs embolized with CH-STS had a 29% lower MAS (P < .001) than those embolized with CH. Residual endoleak was associated with a 53% greater MAS (P < .001). The ICC for MAS was 0.807 (95% confidence interval: 0.754-0.849) between segmentations. CONCLUSIONS: CH-STS confers stiffer intraluminal properties to embolized aneurysms. Persistent endoleaks are associated with increased sac strain, an observation that may help guide management.

Safety and Efficacy of Paclitaxel-Eluting Balloon Angioplasty for Dysfunctional Hemodialysis Access: A randomized trial Comparing with Angioplasty Alone.

PURPOSE: To assess whether angioplasty of hemodialysis access (HA) stenosis with a drug-coated balloon (DCB) would prevent restenosis in comparison with plain-balloon percutaneous transluminal angioplasty (PTA). MATERIALS AND METHODS: This prospective randomized clinical trial enrolled 120 patients with dysfunctional arteriovenous fistulae (n = 109) and grafts (n = 11), due to a ≥50% stenosis between March 2014 and April 2018. All patients underwent high-pressure balloon angioplasty and were then randomized to either DCB (n = 60) or PTA (n = 60). Patients were followed-up for 1 year, and angiography was performed 6 months after angioplasty. The primary endpoint was the late lumen loss (LLL) at 6 months. Secondary endpoints included other angiographic parameters at 6 months and HA failures, adverse event, and mortality at 12 months. Continuous variables were compared with a Student t-test, and Kaplan-Meier curves were used for freedom from HA failure and for mortality. RESULTS: LLL in the DCB and in the PTA group were 0.64 mm ± 1.20 and 1.13 mm ± 1.51, respectively (P = .082, adjusted P = .0498). DCB was associated with lower percentage stenosis (54.2% ± 19.3 vs 61.7% ± 18.2; P = .047) and binary restenosis ≥50% (56.5% vs 81.1%; P = .009) than PTA. The number of HA failures after 12 months was lower for DCB than for PTA (45% vs 66.7%; P = .017). Mortality at 12 months was 10% and 8.3% in the DCB and PTA groups, respectively (P = .75). CONCLUSIONS: Despite LLL improvement that failed to reach statistical significance, this study demonstrated decreased incidence and severity of restenosis with DCB compared with PTA to treat dysfunctional HA.

Eye Lens Dosimetry in Interventional Radiology: Assessment With Dedicated Hp(3) Dosimeters.

PURPOSE: To quantify eye lens dose in interventional radiology and assess whether neck dosimeter is a good surrogate to evaluate eye lens dosimetry. METHODS: Radiation exposure was prospectively measured in 9 interventional radiologists between May and October 2017. Standard Hp(0,07) thermoluminescent dosimeters (TLDs) were worn at the neck outside the lead apron, and 2 dedicated eye lens Hp(3) TLDs were placed just above the eyes, one midline and another at the outer edge of the left eye. Correlations between eye lens and neck TLD doses were assessed with Pearson coefficient, and linear regression was used to predict eye lens dose from neck TLD values. RESULTS: Eye lens dose without eye protection was 0.18 ± 0.11 (mean ± standard deviation; 0.08-0.41) mSv per workday and 35.3 ± 6.6 mSv (16.3-82.9) annually (200 workdays/year). Five (56%) radiologists exceeded the 20 mSv annual eye lens dose limit. Eye lens doses from left and central TLDs were 12.46 ± 3.02 and 9.29 ± 3.38 mSv, respectively (P = .027). Mean eye lens (left and central) and neck TLD doses were 10.87 ± 2.67 and 16.56 ± 5.67 mSv, respectively (P = .008). Pearson correlation coefficient between both eye lens TLD and between mean eye lens TLD and neck TLD doses were 0.91 and 0.92, respectively. Average of eye lens dose was 0.0179 + (0.5971 × neck dose). CONCLUSION: Full-time interventional radiologists are likely to suffer from deterministic radiation effects to the eye lens, especially on the left side. Neck TLD significantly overestimates eye lens dose. However, eye lens doses are highly correlated with neck doses and may be predicted from the neck TLD values.

Use of peripheral plasma aldosterone concentration and response to ACTH during simultaneous bilateral adrenal veins sampling to predict the source of aldosterone secretion in primary aldosteronism.

CONTEXT: Previous studies suggested that plasma aldosterone (PAC) response to ACTH stimulation could predict the subtypes of primary aldosteronism (PA) and avoid adrenal venous sampling (AVS). OBJECTIVE: Assess the usefulness of peripheral (P) PAC response to ACTH stimulation during AVS to identify the source of aldosterone in patients with PA. METHODS: Two hundred and fifteen patients were assigned to four different lateralization ratio (LR) groups based on different combinations of basal (≥ or <2) and post-ACTH LR (≥ or <4). The P vein parameters analysed included as follows: mean basal PAC, maximal PAC (PACmax ), and PAC/C ratio (PACmax /C), PAC absolute increase, PAC relative increase following ACTH bolus (250 mcg IV) and maximal variation of PAC/C ratio between post-ACTH and basal measures. RESULTS: Mean basal PAC was significantly higher in group 1 (basal LR > 2 and post-ACTH > 4) than in group 2 (basal LR > 2, post-ACTH < 4) or group 4 (basal LR < 2 post-ACTH < 4) (P < .001). PACmax , PACmax /C and PAC absolute increase following ACTH were higher in group 1 than the others (P < .017). Using receiver operating characteristic (ROC) curves analysis of groups 1 and 4, best AUC were obtained with mean basal PAC (AUC: 0.757 95% IC: 0.653-0.861), PACmax (AUC: 0.753 95% IC: 0.646-0.860) and PACmax /C (AUC: 0.750 95% IC: 0.646-0.853). CONCLUSION: P mean basal PAC and PACmax and PACmax /C are higher in basal and ACTH lateralized PA than in other groups. Peripheral PAC cut-off values fail to adequately distinguish all groups and cannot replace the requirement to conduct AVS.

Adrenal vein sampling: External validation of multinomial regression modelling and left adrenal vein-to-peripheral vein ratio to predict lateralization index without right adrenal vein sampling.

BACKGROUND: Adrenal vein sampling (AVS) failure is mainly due to right adrenal vein unavailability. Multinomial regression modelling (MRM) and left adrenal vein-to-peripheral vein ratio (LAV/PV) were proposed to predict the lateralization index without the right AVS. OBJECTIVE: To assess external validity of MRM and LAV/PV to predict lateralization index when right adrenal vein sampling is missing. DESIGN: Diagnostic retrospective study. PATIENTS: Development and validation cohorts included AVS of 174 and 122 patients, respectively, from 2 different centres. MEASUREMENTS: Development and validation cohort data were used, respectively, for calibration and for validation of MRM and LAV/PV to predict the lateralization index without the right adrenal vein sampling. Sensitivity and specificity of MRM and LAV/PV were compared between both centres at different pre-established specificity thresholds based on receiver operating characteristic curves generated from the development cohort data. RESULTS: At a specificity threshold of 95% set in the development cohort, specificity values exceeded 90% (range, 90.6%-98.8%) for all verified MRM and LAV/PV models in the validation cohort. Corresponding sensitivities for MRM and LAV/PV, respectively, range from 54.1% to 83.7% and 32.8% to 88.4% for the development cohort compared to 33.3%-87.5% and 2.8%-79.2% for the validation cohort. Overall, diagnostic accuracy of both methods was higher to detect right (82.8%-93.5%) than left (70.2%-80.6%) lateralization index status in both centres. CONCLUSIONS: Minimal changes in specificity from development to validation cohorts validate the use of MRM and LAV/PV to predict the lateralization index when the right AVS is missing. Both methods had better accuracy for right than left lateralization detection.

Feasibility of shear wave sonoelastography to detect endoleak and evaluate thrombus organization after endovascular repair of abdominal aortic aneurysm.

PURPOSE: To investigate the feasibility of shear wave sonoelastography (SWS) for endoleak detection and thrombus characterization of abdominal aortic aneurysm (AAA) after endovascular repair (EVAR). MATERIALS AND METHODS: Participants who underwent EVAR were prospectively recruited between November 2014 and March 2016 and followed until March 2019. Elasticity maps of AAA were computed using SWS and compared to computed tomography angiography (CTA) and color Doppler ultrasound (CDUS). Two readers, blinded to the CTA and CDUS results, reviewed elasticity maps and B-mode images to detect endoleaks. Three or more CTAs per participant were analyzed: pre-EVAR, baseline post-EVAR, and follow-ups. The primary endpoint was endoleak detection. Secondary endpoints included correlation between total thrombus elasticity, proportion of fresh thrombus, and aneurysm growth between baseline and reference CTAs. A 3-year follow-up was made to detect missed endoleaks, EVAR complication, and mortality. Data analyses included Cohen's kappa; sensitivity, specificity, and positive predictive value (PPV); Pearson coefficient; and Student's t tests. RESULTS: Seven endoleaks in 28 participants were detected by the two SWS readers (k = 0.858). Sensitivity of endoleak detection with SWS was 100%; specificity and PPV averaged 67% and 50%, respectively. CDUS sensitivity was estimated at 43%. Aneurysm growth was significantly greater in the endoleak group compared to sealed AAAs. No correlation between growth and thrombus elasticity or proportion of fresh thrombus in AAAs was found. No new endoleaks were observed in participants with SWS negative studies. CONCLUSION: SWS has the potential to detect endoleaks in AAA after EVAR with comparable sensitivity to CTA and superior sensitivity to CDUS. KEY POINTS: • Dynamic elastography with shear wave sonoelastography (SWS) detected 100% of endoleaks in abdominal aortic aneurysm (AAA) follow-up that were identified by a combination of CT angiography (CTA) and color Doppler ultrasound (CDUS). • Based on elasticity maps, SWS differentiated endoleaks from thrombi within the aneurysm sac (p < 0.001). • After 3-year follow-up, no new endoleaks were observed in SWS negative examinations.

Percutaneous Thrombectomy with the JETi8 Peripheral Thrombectomy System for the Treatment of Deep Vein Thrombosis.

PURPOSE: This study evaluated the safety and efficacy of the JETi8 peripheral thrombectomy system in treating acute deep vein thrombosis (DVT). MATERIALS AND METHODS: A retrospective study was conducted in 18 consecutive patients (mean age, 41 years old [range, 15-74 years old]; 5 men and 13 women). There were 21 instances of DVTs (9 iliofemoral, 10 axillosubclavian, and 2 portal), which were treated using the JETi8 thrombectomy device between November 2016 and July 2018. Thrombus was laced with recombinant tissue plasminogen activator (r-TPA) (9.3 mg, on average; range, 2-12 mg) in 17 procedures (81%) prior to thrombectomy. Technical success was defined as restoration of antegrade flow using the JETi8 with or without additional treatment of an underlying obstructive lesion. Procedural success was defined as technical success with or without the addition of overnight catheter-directed thrombolysis (CDT) RESULTS: Mean procedure time was 83 minutes (range, 30-160 minutes), and mean thrombus reduction with the JETi8 alone was 92% (range, 60%-100%). Stent placement was required in 6 procedures (29%). Technical success using the JETi8 system alone was 76% (16 of 21 procedures), whereas 5 procedures (24%) required subsequent overnight CDT in the intensive care unit. Procedural success rate was 100% (20 of 20 procedures). Mean aspirated volume was 531 mL (range, 250-1,230 mL). The only adverse event was a subsegmental pulmonary embolism. Seven patients (33%) were discharged the same day. Recurrent thrombosis was observed in 5 patients (24%), of whom 3 were successfully treated with the JETi8 system. CONCLUSIONS: The JETi8 system may be a safe and effective option for thrombectomy of acute DVT.

Clinical Validation of a Semi-Automated Software for Maximal Diameter Measurements for Endovascular Repair Follow-up.

PURPOSE: To compare automated measurements of maximal diameter (Dmax) of abdominal aortic aneurysm (AAA) orthogonal to luminal or outer wall envelope centerline for endovascular repair (EVAR) follow-up. MATERIAL AND METHODS: Eighty-three consecutive patients with AAA treated by EVAR who had at least 1 computed tomography (CT) scan before and 2 CT scans after EVAR with at least 5 months' interval were included. Three-dimensional reconstruction of the AAA was achieved with dedicated segmentation software. Performances of automated calculation algorithms of Dmax perpendicular to lumen or outer wall envelope centerlines were then compared to manual measurement of Dmax on double-oblique multiplanar reconstruction (gold standard). Accuracy of automated Dmax measurements at baseline, follow-up, and progression over time was evaluated by calculation of mean error, Bland-Altman plot, and regression models. RESULTS: Disagreement in Dmax measurements between outer wall envelope algorithm and manual method was insignificant (mean error: baseline, -0.07 ± 1.66 mm, P = .7; first follow-up, 0.24 ± 1.69 mm, P = .2; last follow-up, -0.41 ± 2.74 mm, P = .17); whereas significant discrepancies were found between the luminal algorithm and the manual method (mean error: baseline, -1.24 ± 2.01 mm, P < .01; first follow-up, -1.49 ± 3.30 mm, P < .01; last follow-up, -1.78 ± 3.60 mm, P < .01). Dmax progression results were more accurate with AAA outer wall envelope algorithm compared to luminal method (P = .2). CONCLUSIONS: AAA outer wall envelope segmentation is recommended to enable automated calculation of Dmax perpendicular to its centerline during EVAR follow-up.

Abdominal aortic aneurysm follow-up by shear wave elasticity imaging after endovascular repair in a canine model.

OBJECTIVES: To investigate if shear wave imaging (SWI) can detect endoleaks and characterize thrombus organization in abdominal aortic aneurysms (AAAs) after endovascular aneurysm repair. METHODS: Stent grafts (SGs) were implanted in 18 dogs after surgical creation of type I endoleaks (four AAAs), type II endoleaks (13 AAAs) and no endoleaks (one AAA). Color flow Doppler ultrasonography (DUS) and SWI were performed before SG implantation (baseline), on days 7, 30 and 90 after SG implantation, and on the day of the sacrifice (day 180). Angiography, CT scans and macroscopic tissue sections obtained on day 180 were evaluated for the presence, size and type of endoleaks, and thrombi were characterized as fresh or organized. Endoleak areas in aneurysm sacs were identified on SWI by two readers and compared with their appearance on DUS, CT scans and macroscopic examination. Elasticity moduli were calculated in different regions (endoleaks, and fresh and organized thrombi). RESULTS: All 17 endoleaks (100 %) were identified by reader 1, whereas 16 of 17 (94 %) were detected by reader 2. Elasticity moduli in endoleaks, and in areas of organized thrombi and fresh thrombi were 0.2 ± 0.4, 90.0 ± 48.2 and 13.6 ± 4.5 kPa, respectively (P < 0.001 between groups). SWI detected endoleaks while DUS (three endoleaks) and CT (one endoleak) did not. CONCLUSIONS: SWI has the potential to detect endoleaks and evaluate thrombus organization based on the measurement of elasticity. KEY POINTS: • SWI has the potential to detect endoleaks in post-EVAR follow-up. • SWI has the potential to characterize thrombus organization in post-EVAR follow-up. • SWI may be combined with DUS in post-EVAR surveillance of endoleak.

Safety and Efficacy of Endovascular Fiducial Marker Insertion for CyberKnife Stereotactic Radiation Therapy Planning in Early-Stage Lung Cancer.

PURPOSE: To evaluate the safety and efficacy of endovascular fiducial markers (EVFMs) for CyberKnife stereotactic radiation therapy (RT) of malignant lung neoplasms in patients with contraindications to percutaneous fiducial marker (PTFM) placement. MATERIALS AND METHODS: Between January 2011 and December 2013, 15 patients (7 men and 8 women) aged 59-87 years (mean, 73 y) underwent EVFM placement and 109 patients (54 men and 55 women) aged 55-92 years (mean, 73 y) underwent 114 PTFM placements. All patients who received EVFMs had contraindications to PTFM insertion. Complications were recorded for all 129 procedures. Proportions of markers used for CyberKnife stereotactic RT planning and distance between markers and tumor were assessed in all 15 patients in the EVFM group and in 15 randomly selected patients in the PTFM group. RESULTS: Sixty-two EVFMs and 56 PTFMs were inserted in the groups of 15 patients. CyberKnife stereotactic RT was not performed in 2 EVFM recipients (8 EVFMs) and 1 PTFM recipient (4 PTFMs). CyberKnife stereotactic RT was planned with the use of 39 of 54 EVFMs (72%) in 13 patients and 37 of 52 PTFMs (71%) in 14 patients. Mean distances between the tumor and EVFMs and PTFMs were 5.5 mm and 2.7 mm, respectively (P = .0152). No complications occurred in the EVFM group. In the PTFM group, 60 of 114 patients (52.6%) had small or moderate pneumothoraxes, 13 (11.4%) had chest tubes inserted, and 5 (4.4%) had self-limiting hemoptysis. CONCLUSIONS: EVFM is feasible and safe, and may therefore offer an alternative when patients are not candidates for percutaneous marker placement.

Endovascular Repair of Abdominal Aortic Aneurysm: Follow-up with Noninvasive Vascular Elastography in a Canine Model.

PURPOSE: To assess the ability of noninvasive vascular elastography (NIVE) to help characterize endoleaks and thrombus organization in a canine model of abdominal aortic aneurysm after endovascular aneurysm repair with stent-grafts, in comparison with computed tomography (CT) and pathologic examination findings. MATERIALS AND METHODS: All protocols were approved by the Animal Care Committee in accordance with the guidelines of the Canadian Council of Animal Care. Stent-grafts were implanted in a group of 18 dogs with aneurysms created in the abdominal aorta. Type I endoleak was created in four aneurysms; type II endoleak, in 13 aneurysms; and no endoleak, in one aneurysm. Doppler ultrasonography and NIVE examinations were performed at baseline and at 1-week, 1-month, 3-month, and 6-month follow-up. Angiography, CT, and macroscopic tissue examination were performed at sacrifice. Strain values were computed by using the Lagrangian speckle model estimator. Areas of endoleak, solid organized thrombus, and fresh thrombus were identified and segmented by comparing the results of CT and macroscopic tissue examination. Strain values were compared by using the Wilcoxon rank-sum and Kruskal-Wallis tests. RESULTS: All stent-grafts were successfully deployed, and endoleaks were clearly depicted in the last follow-up elastography examinations. Maximal axial strains over consecutive heart cycles in endoleak, organized thrombus, and fresh thrombus areas were 0.78% ± 0.22, 0.23% ± 0.02, 0.10% ± 0.04, respectively. Strain values were significantly different between endoleak and organized or fresh thrombus areas (P < .000) and between organized and fresh thrombus areas (P < .0002). No correlation was found between strain values and type of endoleak, sac pressure, endoleak size, and aneurysm size. CONCLUSION: NIVE may be able to help characterize endoleak and thrombus organization, regardless of the size, pressure, and type of endoleak.

Results of a randomized clinical trial of external beam radiation to prevent restenosis after superficial femoral artery stenting.

OBJECTIVE: The objective of this study was to evaluate the safety and efficacy of external beam radiation (EBR) in preventing restenosis after superficial femoral artery (SFA) stenting in comparison with a control group treated with SFA stenting only. METHODS: In this Institutional Review Board-approved study, patients who provided written informed consent were randomly assigned to 0 Gy or 14 Gy of EBR to the stent site 24 hours after SFA stenting. The primary end point was the angiographic binary restenosis rate 2 years after stenting. Categorical and continuous end points were respectively analyzed using logistic regression models and Wilcoxon tests. End points expressed as time to event were analyzed using a log-rank test. RESULTS: The study included 155 patients, 46 women and 109 men (mean age, 66 years; range, 45-85 years). In the 0 and 14 Gy groups, binary restenosis was present, respectively, in 44% (34/77) and 68% (52/76; P = .003) 2 years after stenting. Stent thrombosis occurred in 13% (10/78) of the 0 Gy group and in 33% (25/77) of the 14 Gy group (P = .003). Target lesion revascularization at 2 years was 26% (25/78) in the 0 Gy group and 30% (23/77) in the 14 Gy group (P = .56). There were no significant differences in total walking distances change from baseline to 2 years (46 ± 100 and 26 ± 79 m, respectively, in the 0 Gy and 14 Gy group; P = .25). There were no procedure-related deaths and no major amputations. CONCLUSIONS: A single 14 Gy dose of EBR to the SFA stenting site did not prevent in-stent restenosis.

Adrenal Vein Sampling in Primary Aldosteronism: Sensitivity and Specificity of Basal Adrenal Vein to Peripheral Vein Cortisol and Aldosterone Ratios to Confirm Catheterization of the Adrenal Vein.

PURPOSE: To assess the sensitivity and specificity for ratios of adrenal vein cortisol level (Ca) to peripheral vein cortisol level (Cp), adrenal vein aldosterone level (Aa) to peripheral vein aldosterone level (Ap), and combined cortisol and aldosterone levels ("combined ratio") for the detection of successful adrenal vein catheterization ("selectivity") in adrenal vein sampling (AVS) without adrenocorticotropic hormone (ACTH) injection at different cutoff values. MATERIALS AND METHODS: This retrospective study was approved by the institutional review board, and informed consent was waived. AVS was performed in 160 consecutive patients (49 women and 111 men; mean age, 53.6 years) between December 1989 and January 2014. Cortisol and aldosterone levels were measured in samples from the adrenal veins and left iliac vein every 5 minutes, two times before (basal) and three times after intravenous cosyntropin (ACTH 1-24) injection. Selectivity was defined by Ca/Cp or Aa/Ap ratio of at least 5 in at least one sampling after ACTH administration. Sensitivity and specificity for the detection of selective adrenal vein catheterization were calculated for basal Ca/Cp ratio, Aa/Ap ratio, and combined ratios for three cutoff values reported in the literature. The McNemar test was used to assess differences in sensitivity and specificity to detect selective adrenal vein catheterization. RESULTS: The sensitivity and specificity for the cutoff values of at least 3, at least 2, and at least 1.1 for the detection of AVS selectivity were respectively 50.4% and 100%, 70.8% and 100%, and 98.5% and 76.9% for Ca/Cp ratio; 61.3% and 100%, 70.8% and 100%, and 94.2% and 53.8% for Aa/Ap ratio; and 75.2% and 100%, 88.3% and 100%, and 99.3% and 46.2% for combined ratios (sensitivity at the ≥2 cutoff value: P < .0001 for combined ratio vs Ca/Cp ratio and for combined ratio vs Aa/Ap ratio). CONCLUSION: Basal combined ratio has the best sensitivity for the detection of AVS selectivity at all cutoff values, and for all ratios, the cutoff value of at least 2 has the best sensitivity for 100% specificity.

Source of errors and accuracy of a two-dimensional/three-dimensional fusion road map for endovascular aneurysm repair of abdominal aortic aneurysm.

PURPOSE: To evaluate the accuracy and source of errors using a two-dimensional (2D)/three-dimensional (3D) fusion road map for endovascular aneurysm repair (EVAR) of abdominal aortic aneurysm. MATERIALS AND METHODS: A rigid 2D/3D road map was tested in 16 patients undergoing EVAR. After 3D/3D manual registration of preoperative multidetector computed tomography (CT) and cone beam CT, abdominal aortic aneurysm outlines were overlaid on live fluoroscopy/digital subtraction angiography (DSA). Patient motion was evaluated using bone landmarks. The misregistration of renal and internal iliac arteries were estimated by 3 readers along head-feet and right-left coordinates (z-axis and x-axis, respectively) before and after bone and DSA corrections centered on the lowest renal artery. Iliac deformation was evaluated by comparing centerlines before and during intervention. A score of clinical added value was estimated as high (z-axis < 3 mm), good (3 mm ≤ z-axis ≤ 5 mm), and low (z-axis > 5 mm). Interobserver reproducibility was calculated by the intraclass correlation coefficient. RESULTS: The lowest renal artery misregistration was estimated at x-axis = 10.6 mm ± 11.1 and z-axis = 7.4 mm ± 5.3 before correction and at x-axis = 3.5 mm ± 2.5 and z-axis = 4.6 mm ± 3.7 after bone correction (P = .08), and at 0 after DSA correction (P < .001). After DSA correction, residual misregistration on the contralateral renal artery was estimated at x-axis = 2.4 mm ± 2.0 and z-axis = 2.2 mm ± 2.0. Score of clinical added value was low (n = 11), good (n= 0), and high (n= 5) before correction and low (n = 5), good (n = 4), and high (n = 7) after bone correction. Interobserver intraclass correlation coefficient for misregistration measurements was estimated at 0.99. Patient motion before stent graft delivery was estimated at x-axis = 8 mm ± 5.8 and z-axis = 3.0 mm ± 2.7. The internal iliac artery misregistration measurements were estimated at x-axis = 6.1 mm ± 3.5 and z-axis = 5.6 mm ± 4.0, and iliac centerline deformation was estimated at 38.3 mm ± 15.6. CONCLUSIONS: Rigid registration is feasible and fairly accurate. Only a partial reduction of vascular misregistration was observed after bone correction; minimal DSA acquisition is still required.

Clinical validation of semi-automated software for volumetric and dynamic contrast enhancement analysis of soft tissue venous malformations on magnetic resonance imaging examination.

OBJECTIVES: To evaluate venous malformation (VM) volume and contrast-enhancement analysis on magnetic resonance imaging (MRI) compared with diameter evaluation. METHODS: Baseline MRI was undertaken in 44 patients, 20 of whom were followed by MRI after sclerotherapy. All patients underwent short-tau inversion recovery (STIR) acquisitions and dynamic contrast assessment. VM diameters in three orthogonal directions were measured to obtain the largest and mean diameters. Volumetric reconstruction of VM was generated from two orthogonal STIR sequences and fused with acquisitions after contrast medium injection. Reproducibility (interclass correlation coefficients [ICCs]) of diameter and volume measurements was estimated. VM size variations in diameter and volume after sclerotherapy and contrast enhancement before sclerotherapy were compared in patients with clinical success or failure. RESULTS: Inter-observer ICCs were similar for diameter and volume measurements at baseline and follow-up (range 0.87-0.99). Higher percentages of size reduction after sclerotherapy were observed with volume (32.6 ± 30.7%) than with diameter measurements (14.4 ± 21.4%; P = 0.037). Contrast enhancement values were estimated at 65.3 ± 27.5% and 84 ± 13% in patients with clinical failure and success respectively (P = 0.056). CONCLUSIONS: Venous malformation volume was as reproducible as diameter measurement and more sensitive in detecting therapeutic responses. Patients with better clinical outcome tend to have stronger malformation enhancement. KEY POINTS: • Magnetic resonance imaging readily demonstrates diameters and volumes of venous malformations • MRI diameter calculations are reproducible in estimating the size of venous malformations • But volumetric models of malformations are more sensitive in detecting therapeutic response • Dynamic enhancement is also better assessed with automated volumetric software • Volumetric analysis of malformations offers promise to guide therapy and assess response.