Association between Baseline Osteoarthritic Features on MR Imaging and Clinical Outcome after Genicular Artery Embolization for Knee Osteoarthritis

PurposeTo explore the association between baseline osteoarthritis (OA)-related magnetic resonance (MR) imaging features and pain reduction after genicular artery embolization (GAE) in patients with mild-to-moderate symptomatic knee OA resistant to conservative therapy.Materials and MethodsThis was a retrospective analysis of patients with mild-to-moderate symptomatic knee OA treated with GAE using imipenem-cilastatin sodium. The clinical outcome was scored at baseline and 6 months after treatment using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). MR images were scored using the MR imaging osteoarthritis knee score. Linear regression was used to evaluate associations of before-treatment MR imaging scores with WOMAC_pain and WOMAC_total reduction after 6 months.ResultsFifty-four patients (22.2% male; median age, 69.4 years; median WOMAC_pain at baseline, 12) were evaluated. Of all OA features scored, a higher cartilage full-thickness defect score showed the strongest association with less reduction of both WOMAC_pain (B,?0.63 [95% confidence interval (CI), ?0.91 to ?0.34]; P < .001) and WOMAC_total scores (B, ?1.77 [95% CI, ?2.87 to ?0.67]; P < .001) following treatment. The presence of grade 2–3 effusion synovitis (B, ?2.99 [95% CI, ?5.39 to ?0.60]) bone marrow lesions (B, ?0.52 [95% CI, ?0.86 to ?0.19]), osteophytes (B, ?0.21 [95% CI, ?0.36 to ?0.06]), and cartilage defect surface area score (B, ?0.25 [95% CI ?0.42 to ?0.08]) all showed a significant association with less WOMAC_pain reduction (all P < .05).ConclusionsIn patients with mild-to-moderate symptomatic knee OA treated with GAE, the presence and severity of full-thickness cartilage defects, effusion synovitis, bone marrow lesions, osteophytes, and cartilage surface area scores at baseline are associated with less favorable clinical outcomes at 6 months.     

Multicenter Randomized Sham Controlled Study of Genicular Artery Embolization for Knee Pain Secondary to Osteoarthritis

PurposeTo assess the safety and efficacy of genicular artery embolization (GAE) compared with a sham procedure in the treatment of knee pain secondary to mild to moderate osteoarthritis (OA).Materials and MethodsA multicenter, single-blinded, randomized controlled trial was conducted to evaluate knee OA symptom reduction after GAE versus sham procedure. Subjects (n = 21) with mild to moderate OA and intractable knee pain were randomized 2:1 to either GAE or a sham procedure. Subjects who were randomized to the sham procedure and did not report clinical improvement in both the total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and visual analog scale (VAS) scores were unblinded and able to crossover to treatment at 1 month. Longitudinal data were collected for 12 months, and subjects were excluded if they required additional analgesics at follow-up. Reductions in the VAS and total WOMAC scores were compared using mixed-effects linear regression models.ResultsAll subjects in the sham group failed to show significant improvements at 1 month and crossed over to the treatment arm. There was a statistically significantly greater pain reduction in the treatment group than in the sham group at 1 month (VAS, 50.1 mm; standard error [SE], 10.6; 95% confidence interval [CI], 29.0, 72.3; P<.01). Disability improvement was also significantly greater in the treatment group (WOMAC, 24.7 points; SE, 10.4; 95% CI, 3.5, 45.9; P=.02). Only minor adverse events were reported. Five subjects were excluded after increased analgesic use. Sensitivity analysis with all excluded patients confirmed significant improvements at 1 and 12 months.ConclusionIn patients with mild to moderate knee OA, GAE results in symptomatic improvement greater than the sham procedure with clinically significant reduction in pain and disability.     

Genicular Artery Embolization for the Treatment of Knee Pain Secondary to Osteoarthritis

PurposeTo evaluate the efficacy and safety of embolization of hyperemic synovial tissue for the treatment of knee pain secondary to osteoarthritis (OA).Materials and MethodsTwenty patients with radiographic knee OA and moderate-to-severe pain refractory to conservative therapy were enrolled in a prospective, 2-site pilot study. Genicular artery embolization (GAE) was performed with 75- or 100-μm spherical particles. Patients were assessed with magnetic resonance imaging at baseline and at 1 month and with the Visual Analogue Scale (VAS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at baseline and at 1, 3, and 6 months. Adverse events were recorded at all timepoints.ResultsEmbolization of at least 1 genicular artery was achieved in 20/20 (100%) patients. Mean VAS improved from 76 mm ± 14 at baseline to 29 mm ± 27 at 6-month follow-up (P < .01). Mean WOMAC score improved from 61 ± 12 at baseline to 29 ± 27 at 6-month follow-up (P < .01). Self-limiting skin discoloration occurred in 13/20 (65%) patients. Two of 20 (10%) patients developed plantar sensory paresthesia that resolved within 14 days.ConclusionsGAE to treat knee pain secondary to OA can be performed safely and demonstrates potential efficacy. Further randomized comparative studies are needed to determine true treatment effect versus placebo effect.     

The Value of Preprocedural MR Imaging in Genicular Artery Embolization for Patients with Osteoarthritic Knee Pain

PurposeTo determine the value of preprocedural MR imaging in genicular artery embolization (GAE) for patients with osteoarthritic knee pain.Materials and MethodsThis single-center study retrospectively analyzed 28 knees in 18 patients who underwent GAE for intractable knee pain < 1 month after MR imaging. The pain experienced in each knee was evaluated on a 100-mm visual analog scale (VAS) at baseline and 1- and 3-month after GAE. “GAE responders” were defined as knees that exhibited greater than 30% reduction of VAS pain scores from baseline at both follow-up visits. Musculoskeletal radiologists evaluated MR images of the affected knee compartment regarding cartilage defects, osteophytes, subchondral cysts, bone marrow lesions (BMLs), meniscal injury, and joint effusion. The performances of Kellgren–Lawrence (KL) grading and MR findings in predicting GAE responders was estimated based on receiver operating characteristic curves.ResultsThe mean VAS pain score was 84.3 mm. BML (area under the curve [AUC], 0.860; P < .001), meniscal injury (AUC, 0.811; P = .003), and KL grading (AUC, 0.898; P < .001) were significantly associated with GAE outcome. To predict GAE responders, KL grade ≤ 2 yielded a sensitivity of 87.5% and a specificity of 60.9%, BML grade ≤ 1 yielded a sensitivity of 75.0% and a specificity of 69.6%, and meniscal injury grade ≤ 2 yielded a sensitivity of 83.3% and a specificity of 72.7%.ConclusionsLarge BMLs and severe meniscal injuries on MR imaging, as well as high KL grades, indicated poor responses to GAE.     

Short-Term Effects of Genicular Artery Embolization on Symptoms and Bone Marrow Abnormalities in Patients with Refractory Knee Osteoarthritis

PurposeTo evaluate the short-term outcomes of genicular artery embolization (GAE) for knee osteoarthritis (OA) with and without bone marrow lesion (BML) and/or subchondral insufficiency fracture of the knee (SIFK).Materials and MethodsThis single-institution prospective observational pilot study analyzed 24 knees in 22 patients with mild to moderate knee OA, including 8 knees without BML, 13 knees with BML, and 3 knees with both BML and SIFK. The area and volume of BMLs on magnetic resonance images were measured before and after GAE. Baseline and postoperative pain and physical function were assessed using the visual analog scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).ResultsGAE significantly reduced the BML area and volume 3 months after embolization in the knees with BML (both P < .0005). GAE significantly decreased the VAS scores at 3 and 6 months after embolization in patients without BML (both P = .04) and those with BML (both P = .01). GAE also lowered the WOMAC scores 3 months after embolization in patients without and with BML (P = .02 and P = .0002, respectively). However, GAE did not significantly alter the BML area and volume (both P = .25), VAS scores (P = 1.00), and WOMAC scores (P = .08) in patients with BML and SIFK at 3 months after GAE.ConclusionsThis observational pilot study suggested that GAE effectively reduces the BML area and volume and improves pain and physical function in patients with knee OA accompanied by BML but is inefficacious in those with both BML and SIFK.     

Woodchuck Hepatic Anatomy and Vascular Alterations Due to Hepatocellular Carcinoma with Angiographic Atlas of the Abdomen and Pelvis

PurposeTo characterize the hepatic and abdominal angiographic anatomy of woodchucks and vascular changes associated with hepatocellular carcinoma (HCC).Materials and MethodsTwenty-nine woodchucks (23 with viral-associated HCC, 6 without) underwent multiphasic computed tomography (CT). Fourteen woodchucks (8 with HCC) also underwent diagnostic angiography. Hepatic arterial diameters were measured on the CT scans. Woodchucks were divided into 3 groups: non–tumor-bearing, largest tumor supplied by the right hepatic artery (RHA), and largest tumor supplied by the left hepatic artery (LHA). Statistical analysis with a repeated measures model was performed to determine the effects of tumor location (right, left), vessel measured (RHA, LHA), and interaction between the 2 on vessel diameter. Lobar arteries supplying HCC were compared with those that did not.ResultsCT anatomy and normal and variant vascular anatomy were defined. In woodchucks with HCC, LHA and RHA supplying tumors had mean diameters of 2.0 mm ± 0.3 and 1.6 mm ± 0.3 versus 1.5 mm ± 0.3 and 1.1 mm ± 0.2 for non–tumor-supplying arteries (P = .0002 and P < .0001), respectively. Lobar arteries supplying tumors were similarly ectatic. The right lateral lobe artery had the most profound increase in the mean diameter when supplying tumors, measuring 1.7 mm ± 0.1 versus 1.0 mm ± 0.1 in the non–tumor-supplying artery (P < .0001). There were no differences in the diameters of the aorta and celiac, common, and proper hepatic arteries between tumor- and non–tumor-bearing woodchucks. An angiographic atlas of the abdominal vessels was generated.ConclusionsHCC tumoral vasculature in woodchucks was ectatic compared with normal vasculature. This phenomenon recapitulates human HCC and may facilitate investigation of transcatheter and drug delivery therapies in an HCC animal model.     

Bronchial Artery Aneurysm: Prevalence,Clinical Characteristics,and Long-Term Prognosis Following Bronchial Artery Embolization

PurposeTo investigate the prevalence, clinical characteristics, and long-term prognosis of bronchial artery aneurysm (BAA) following bronchial artery embolization (BAE).Materials and MethodsThe medical records of consecutive patients who underwent bronchial artery angiography between August 2013 and December 2019 were retrospectively reviewed. Patients who were diagnosed with BAA during this period were included in this study. The prevalence, patients’ characteristics, symptoms, comorbidities, angiographic findings, and long-term prognosis following BAE were investigated.ResultsBAA was observed in 20 of 508 patients who underwent bronchial artery angiography (3.9%). The patients’ median age was 69 (interquartile range [IQR], 63.5–76.7) years. The main causes of BAA were cryptogenic, bronchiectasis or cystic fibrosis, and pulmonary aspergillosis. The median diameter of ruptured BAAs was significantly smaller than that of unruptured BAAs (5.4 mm [IQR, 4.8–7.3 mm] vs 9.0 mm [IQR, 7.2–13.9 mm], P = .009). All the patients were successfully treated with BAE, without major adverse events. The median follow-up period after BAE was 970 (IQR, 561–1,796) days. The BAA-related survival rate was 100% at 2 and 3 years after BAE, and the overall survival rate after BAE was 89.2% (95% confidence interval [CI] 89.0–89.3) at 2 years and 74.3% (95% CI 74.0–74.5) at 3 years. BAA-related adverse events and mortality did not occur during the follow-up period.ConclusionsBAA was observed in 3.9 % (20/508) of the patients who underwent bronchial artery angiography. All the patients with BAA were successfully treated with BAE. BAA rupture and consequent mortality did not occur during the follow-up period.     

First-in-Human Study with Eight Patients Using an Absorbable Vena Cava Filter for the Prevention of Pulmonary Embolism

PurposeTo prospectively evaluate the initial human experience with an absorbable vena cava filter designed for transient protection from pulmonary embolism (PE).Materials and MethodsThis was a prospective, single-arm, first-in-human study of 8 patients with elevated risk of venous thromboembolism (VTE). Seven absorbable IVC filters (made of polydioxanone that breaks down into H₂O and CO₂ in 6 mo) were placed prophylactically before orthopedic (n = 5) and gynecologic (n = 2) surgeries, and 1 was placed in a case of deep vein thrombosis. Subjects underwent CT cavography and abdominal radiography before and 5, 11, and 36 weeks after filter placement to assess filter migration, embolization, perforation, and caval thrombosis and/or stenosis. Potential PE was assessed immediately before and 5 weeks after filter placement by pulmonary CT angiography.ResultsNo symptomatic PE was reported throughout the study or detected at the planned 5-week follow-up. No filter migration was detected based on the fixed location of the radiopaque markers (attached to the stent section of the filter) relative to the vertebral bodies. No filter embolization or caval perforation was detected, and no caval stenosis was observed. Throughout the study, no filter-related adverse events were reported.ConclusionsImplantation of an absorbable vena cava filter in a limited number of human subjects resulted in 100% clinical success. One planned deployment was aborted as a result of stenotic pelvic veins, resulting in 89% technical success. No PE or filter-related adverse events were observed.     

Preintervention Computed Tomography Improves the Performance of Endovascular Intervention in Patients with Abdominopelvic Trauma

PurposeTo evaluate the role of computed tomography (CT) and CT angiography in guiding endovascular arteriography (EA) and embolization in hemodynamically (HD) stable and unstable patients with abdominal and/or pelvic (AP) trauma.Materials and MethodsA retrospective review was performed of patients with AP trauma who underwent EA with or without embolization (from January 2012 to August 2020) at an urban, level I trauma center. Patients aged <18 years or those undergoing EA outside of the abdomen and/or pelvis were excluded. Demographics, imaging findings, procedure length, contrast agent administration, laboratory values, and outcomes were compared on the basis of preprocedural imaging technique and hemodynamic status.ResultsA total of 190 patients with AP trauma underwent EA with or without embolization; among them, 123 were HD stable and underwent CT/CT angiography, whereas 67 were initially HD unstable and underwent operative management prior to EA. Of these patients, 38 underwent CT/CT angiography after hemodynamic stability was achieved prior to postoperative EA. The incidence of therapeutic embolization for arterial injury on EA was significantly higher in patients with preprocedural CT/CT angiography (65.8% vs 44.8%, P = .04). The positive and negative predictive values of CT angiography for arterial injury at the time of EA were 92.3% and 100%, respectively. Prior imaging was associated with a reduced contrast agent requirement at the time of EA and reduced transfusion requirement (P = .05 and P = .02). No significant differences were observed in adverse outcomes for patients undergoing preprocedural imaging.ConclusionsCT or CT angiography prior to EA for HD stable and unstable patients with AP trauma may improve the likelihood of therapeutic embolization and enable improved procedure metrics without increasing adverse outcomes.     

Endovascular Treatment Outcome and CT Angiography Findings in Acute Basilar Artery Occlusion with and without Underlying Intracranial Atherosclerotic Stenosis

PurposeTo compare clinical characteristics and treatment outcomes of intra-arterial thrombectomy (IAT) in acute basilar artery occlusion (BAO) with and without underlying intracranial atherosclerotic stenosis (ICAS) and to investigate the usefulness of preprocedural CT angiography findings in the diagnosis of ICAS.Materials and MethodsTwenty patients who received IAT for acute BAO between September 2014 and March 2019 were included. Additional therapies such as angioplasty, stent placement, and tirofiban infusion were provided while treating ICAS. Clinical and angiographic results of treatment were recorded. Preprocedural CT angiography findings in ICAS and non-ICAS groups were compared to assess (i) basilar tip opacification, (ii) partial occlusion, (iii) presence of convex border, (iv) occlusion segment longer than two thirds of the basilar artery or 20 mm, (v) dense basilar artery, and (vi) wall calcification in the occluded segment.ResultsAmong the 20 patients (mean age, 71.3 y; mean stroke score, 24.8), optimal recanalization was achieved in 19 (95%). Three patients had good clinical outcomes. There were 6 patients with underlying ICAS. No difference was observed between ICAS and non-ICAS groups in terms of optimal angiographic recanalization and good outcome. On CT angiography, basilar tip occlusion (100% vs 29%), partial occlusion (100% vs 83%), and long occlusion length (100% vs 14%) significantly differed between the groups (P ≤ .01).ConclusionsIn acute BAO, underlying ICAS does not affect optimal recanalization rate or clinical outcome. Preprocedural CT angiography is a potentially useful tool to detect it.     

Monopolar Radiofrequency Energy Delivered by a Conductive Endovascular Basket or Guidewire Leads to Thermal Occlusion in a Swine Model

PurposeTo assess the feasibility of inducing vascular occlusion by application of radiofrequency (RF) energy via conductive endovascular wires or baskets.Materials and MethodsA retrievable nitinol basket and stainless steel guidewire with a platinum tip were evaluated as conductors for endovascular application of RF energy. Tissue-mimicking thermochromic gel phantoms that change color with heating were cast with 2-, 5-, and 7-mm-diameter lumens and filled with 37 ^oC saline. After ablation, the phantoms were sectioned, and the thermal footprints were evaluated. Six castrated male domestic swine underwent endovascular ablation using the basket in iliac arteries and guidewires in renal arteries. Post-procedural angiography was performed, and postmortem arterial segments were resected for histopathologic analysis.ResultsIn the phantom, the depth of thermal change in the 5- and 7-mm lumens averaged 6.3 and 6.0 mm along the basket, respectively, and in the 2- and 5-mm lumens, the depth of thermal change averaged 1.9 and 0.5 mm along the wire, respectively. In the swine, RF energy delivery led to angiographic occlusion at 12 of 13 sites. Thermal injury and occlusion were similar at the proximal, middle, and distal basket treatment zone, whereas injury and occlusion decreased from the proximal to the distal end of the 5-cm wire treatment zone.ConclusionsEndovascular delivery of RF energy via a conductive basket in medium-sized arteries or a guidewire in small arteries led to acute angiographic and histologic occlusion. The potential to induce stasis might be useful in settings where rapid occlusion is desirable.     

Impact of Intrahepatic Venovenous Shunt on Hepatic Venous Pressure Gradient Measurement

PurposeTo quantitatively analyze the impact of intrahepatic venovenous shunt (IHVS) on hepatic venous pressure gradient (HVPG) measurement.Materials and MethodsFrom 2015 to 2019, 222 HVPG measurements performed during transjugular intrahepatic portosystemic shunt creation were eligible for this study. Digital subtraction angiography (DSA) software color-coded each pixel of a two-dimensional DSA series by time-intensity curve to classify IHVS. Different degrees of IHVS were found in 36.5% of patients (81/222). Mild IHVS was found in 10.8% of patients (24/222), moderate IHVS was found in 10.8% of patients (24/222), and severe IVHS was found in 14.9% of patients (33/222).ResultsMean wedged hepatic vein pressure (WHVP) and HVPG were significantly lower in patients with IHVS compared with patients without IHVS (WHVP: 17.78 mm Hg ± 7.00 vs 24.89 mm Hg ± 8.69, P = .001; HVPG: 11.93 mm Hg ± 5.76 vs 18.6 mm Hg ± 6.85, P < .001). Mild IHVS had little effect on WHVP and HVPG. Mean WHVP and HVPG were 11 mm Hg lower in patients with moderate IHVS (WHVP: 20.38 mm Hg ± 8.38 vs 31.5 mm Hg ± 9.39, P = .026; HVPG: 13.88 mm Hg ± 6.33 vs 25.00 mm Hg ± 9.81, P < .001) and 15 mm Hg lower in patients with severe IHVS (WHVP: 13.45 mm Hg ± 5.28 vs 28.64 mm Hg ± 6.38, P = .017; HVPG: 8.27 mm Hg ± 3.85 vs 23.45 mm Hg ± 6.95, P < .001) than mean portal vein pressure and portal vein gradient.ConclusionsFor patients with moderate or severe IHVS, HVPG might greatly underestimate the actual value of portal vein pressure, and the portal vein should be catheterized to measure portal pressure.     

Elective Embolization of Splenic Artery Aneurysms with an Ethylene Vinyl Alcohol Copolymer Agent (Squid) and Detachable Coils

PurposeTo report the safety and efficacy of the embolization of splenic artery aneurysms (SAAs) with coils plus ethylene vinyl alcohol copolymer (EVOH) agent.Materials and MethodsA single-center retrospective study was conducted from 2016 to 2019 to collect SAAs. Twelve asymptomatic patients (mean age, 59 years) with 15 SAAs (mean size, 23.6 mm; size range, 15–40 mm) were treated with embolization. Embolization was performed with EVOH (Squid 8/34) and fibered detachable coils. Transfemoral embolization was performed with a microcatheter to achieve a splenic artery occlusion embolizing the SAA and its efferent and afferent branches. Follow-up was based on color Doppler ultrasound at 24 hours and on computed tomography (CT) angiography at 1 (n = 12) and 6 months (n = 12) after embolization. Mean number of coils and Squid vials used for each patient, major/minor complications, technical success, 30-day clinical success, cases of revascularization/reintervention, and mortality were assessed. Technical success was defined as complete exclusion of the aneurysmal segment and cessation of blood flow into the sac. Clinical success at 1 month was based on the absence of clinical symptoms and the exclusion of aneurysm revascularization on CT angiography.ResultsThe mean number of coils and Squid vials was 5.75 (standard deviation [SD], 1.58; range, 3–9) and 1.41 (SD, 0.49; range, 1–2), respectively. Both technical and 30-day clinical success were 100%, with no cases of aneurysm revascularization (CT angiography performed in all patients at 1 month and 6 months and in 3 patients at 24 months). No major complications or fatal events were recorded. In terms of minor complications, 2 cases of mild pancreatitis (transient amylases increase) and 1 case of focal splenic ischemia without clinical sequelae were recorded.ConclusionsEmbolization in SAAs using coils plus EVOH was safe and effective without SAA revascularization     

Lack of Growth of Small (≤2 mm Feeding Artery) Untreated Pulmonary Arteriovenous Malformations in Patients with Hereditary Hemorrhagic Telangiectasia

PurposeTo assess pulmonary arteriovenous malformation (PAVM) growth among patients with untreated PAVMs using imaging from long-term follow-up per hereditary hemorrhagic telangiectasia international guidelines.Materials and MethodsAnalysis included 88 untreated PAVMs from 21 patients (6 male;15 female; mean age at presentation 47 y; range, 12–68 y). Two CT studies with the longest interval between were evaluated (mean 8.4 y; median 8.8 y; range, 3.1–14.1 y). Measurement of feeding artery diameter and anteroposterior (AP) and mediolateral (ML) sac dimensions for each PAVM was performed separately by 2 radiologists blinded to patient and CT order. Statistical analysis was performed to determine change in size between earliest and follow-up imaging.ResultsMean feeding artery diameter, AP sac dimension, and ML sac dimension were 1.4 mm (range, 0.8–3.7 mm), 4.3 mm (range, 2.1–11.1 mm), and 4.1 mm (range, 1.8–9.2 mm) on earliest imaging and 1.4 mm (range, 0.9–2.6 mm), 4.5 mm (range, 2.2–12.2 mm), and 4.3 mm (range, 2.0–9.6 mm) on follow-up. Model-based mean analysis showed no statistically significant change in dimension of any variable between earliest and follow-up imaging. Secondary analysis including age also found no statistically significant difference (feeding diameter, P = .09; AP sac dimension, P = .9; ML sac dimension, P = .1). Analysis including time between measurements found no significant relationship between change in variables and time (feeding artery diameter, P = .4; AP sac dimension, P = .3; ML sac dimension, P = .06).ConclusionsUntreated PAVMs grew slowly, if at all, in a near-decade span, and any demonstrated growth was minimal. These findings challenge the current recommendation of 3- to 5-year CT follow-up.     

Comparison of Minimally Invasive Procedures to Treat Knee Pain Secondary to Osteoarthritis: A Systematic Review and Meta-Analysis

PurposeTo review and indirectly compare the outcomes of genicular artery embolization (GAE), radiofrequency (RF) ablation, and intra-articular (IA) injection for the treatment of knee pain secondary to osteoarthritis (OA).Materials and MethodsA literature review of the MEDLINE and Cochrane databases was conducted with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement in June 2020. The visual analog scale (VAS) was recorded at baseline and at all available time points for each therapy. Standard mean differences were calculated at each time point and compared between treatments to assess the magnitude of the treatment effect.ResultsAll 3 treatments demonstrated significant differences in VAS scores after therapy. RF ablation produced the greatest significant mean reduction in relative VAS score from baseline at 1 year of follow-up (mean, 0.49; 95% confidence interval, 0.4–0.59; P = .03). GAE reported the most significant reductions in VAS scores across all measured time points. Overall, the comparison did not demonstrate a significant difference in VAS scores among patients receiving IA injections, RF ablation, and GAE.ConclusionsThe current evidence does not suggest a significant difference in outcomes among IA injection, RF ablation, and GAE for knee pain secondary to OA.     

Radiation-Free Thoracic Endovascular Aneurysm Repair with Fiberoptic and Electromagnetic Guidance: A Phantom Study

PurposeTo evaluate the feasibility and accuracy of a radiation-free implantation of a thoracic aortic stent graft employing fiberoptic and electromagnetic tracking in an anthropomorphic phantom.Materials and MethodsAn anthropomorphic phantom was manufactured based on computed tomography (CT) angiography data from a patient. An aortic stent graft application system was equipped with a fiber Bragg gratings and 3 electromagnetic sensors. The stent graft was navigated in the phantom by 3 interventionalists using the tracking data generated by both technologies. One implantation procedure was performed. The technical success of the procedure was evaluated using digital subtraction angiography and CT angiography (before and after the intervention). Tracking accuracy was determined at various anatomical landmarks based on separately acquired fluoroscopic images. The mean/maximum errors were measured for the stent graft application system and the tip/end of the stent graft.ResultsThe procedure resulted in technical success with a mean error below 3 mm for the entire application system and <2 mm for the position of the tip of the stent graft. Navigation/implantation and handling of the device were rated sufficiently accurate and on par with comparable, routinely used stent graft application systems.ConclusionsThe study demonstrates successful stent graft implantation during a thoracic endovascular aortic repair procedure employing advanced guidance techniques and avoiding fluoroscopic imaging. This is an essential step in facilitating the implantation of stent grafts and reducing the health risks associated with ionizing radiation during endovascular procedures.     

Transarterial Chemoembolization in a Woodchuck Model of Hepatocellular Carcinoma

PurposeTo assess the feasibility of transarterial chemoembolization with drug-eluting embolic (DEE) microspheres in a woodchuck model of hepatocellular carcinoma (HCC).Materials and MethodsNine woodchucks were studied: 4 normal animals and 5 animals infected with woodchuck hepatitis virus in which HCC had developed. Three animals with HCC underwent multidetector CT. A 3-F sheath was introduced into the femoral artery, and the hepatic arteries were selectively catheterized with 2.0–2.4-F microcatheters. Normal animals underwent diagnostic angiography and bland embolization. Animals with HCC underwent DEE transarterial chemoembolization with 70–150-μm radiopaque microspheres loaded with 37.5 mg doxorubicin per milliliter. Cone-beam CT and multidetector CT were performed. Following euthanasia, explanted livers underwent micro-CT, histopathologic examination, and fluorescence imaging of doxorubicin.ResultsThe tumors were hypervascular and supplied by large-caliber tortuous vessels, with arteriovenous shunts present in 2 animals. There was heterogeneous enhancement on multidetector CT with areas of necrosis. Six tumors were identified. The most common location was the right medial lobe (n = 3). Mean tumor volume was 30.7 cm³ ± 12.3. DEE chemoembolization of tumors was achieved. Excluding the 2 animals with arteriovenous shunts, the mean volume of DEE microspheres injected was 0.49 mL ± 0.17. Fluorescence imaging showed diffusion of doxorubicin from the DEE microspheres into the tumor.ConclusionsWoodchuck HCC shares imaging appearances and biologic characteristics with human HCC. Selective catheterization and DEE chemoembolization may similarly be performed. Woodchucks may be used to model interventional therapies and possibly characterize radiologic–pathologic correlations.     

Intra-articular Injection of Bone Marrow Concentrate for Treatment of Patellofemoral Osteoarthritis: Preliminary Results Utilizing an Ultrasound-Guided Marrow Harvesting Technique

ObjectiveTo assess the effectiveness of intra-articular injection of bone marrow concentrate (BMC) under ultrasound (US) guidance in the treatment of patellofemoral osteoarthritis (OA), with clinical and volumetric magnetic resonance (MR) imaging follow-up.MethodsThis retrospective study included 96 consecutive patients referred for US-guided intra-articular injection of BMC for symptomatic patellofemoral OA for which conservative treatment had failed. A control group of 21 patients with symptomatic patellofemoral OA was included for comparison. Data on International Knee Documentation Committee (IKDC), Visual Analog Scale (VAS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores as well as volumetric MR imaging (using T2 mapping sequence) were collected before and 12 months after injection, and the results were compared.ResultsNo technical adverse events were noted during bone marrow aspiration, BMC preparation, or intra-articular injection of BMC. No clinical adverse events were reported during long-term follow-up. All mean scores improved between baseline and 12 months after intra-articular injection of BMC (VAS 5.5 to 3.6, P < .0001; WOMAC 36.8 to 22.2, P < .0001; and IKDC 41.8 to 58.2, P < .0001). MR imaging at 1 year of follow-up after BMC treatment showed no statistically significant difference in hyaline cartilage volume compared with that at the baseline (P = .690), suggesting stabilization of the cartilage degradation process. In contrast, the group of untreated patients showed a significant decrease in the cartilage volume (P = .001), corresponding to a cartilage loss of 6.9%.ConclusionsThe results suggest that intra-articular injection of BMC under US guidance could be a promising option for the treatment of symptomatic patellofemoral OA and could promote the preservation of healthy residual cartilage volume.     

A Motion Artifact Correction Algorithm for Cone-Beam CT in Patients with Hepatic Malignancies Treated with Transarterial Chemoembolization

PurposeTo evaluate the effect of a motion artifact correction algorithm (MACA) on cone-beam computed tomography (CT) during transarterial chemoembolization for hepatic malignancies.Materials and MethodsFrom June 2020 to March 2021, 42 patients with mild-to-severe motion artifacts detected using single cone-beam CT scans were evaluated retrospectively. The image quality of native and motion-corrected data was compared. The maximum intensity, sharpness, and full width at half maximum (FWHM) of 5 segmental hepatic arteries were quantitatively measured. The overall quality of maximum intensity projection (MIP) images, conspicuity of tumor-supplying arteries, and need for selective angiography to ascertain the vascular anatomy were qualitatively evaluated by multiple readers. Paired t and Wilcoxon signed rank tests were used to compare the parameters.ResultsThe mean maximum intensity and sharpness increased from 2,792.01 HU ± 451.36 to 3,148.40 HU ± 594.46 and from 0.31 ± 0.02/mm to 0.34 ± 0.02/mm, respectively, using the MACA (both P < .001). The MACA decreased the mean FWHM from 2.02 mm ± 0.27 to 1.78 mm ± 0.26 (P < .001). The overall quality of the MIP images and the conspicuity of the tumor-supplying artery were enhanced from 2.5 to 3.0 points and from 3.0 to 4.0 points, respectively (both P < .001). Selective angiography was expected to be omitted in 7 cases (16.7%, 7/42) after using the MACA.ConclusionsThe MACA significantly improved both quantitative and qualitative image quality of cone-beam CT in selected patients with motion artifacts during transarterial chemoembolization for hepatic malignancies.