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Background: The incidence of localized intravascular coagulopathy (LIC) in venous malformations varies with lesion size and location, as well as the presence of palpable phleboliths. The development of LIC can cause pain and hemorrhage and can progress to disseminated intravascular coagulopathy (DIC) and thromboembolic disease resulting in death in some cases. Early recognition of LIC can relieve symptoms and prevent progression to life-threatening complications. Objective: The aim of this work was to identify MRI features of venous malformation associated with LIC. We hypothesized that venous malformations with larger capacitance, slower flow and less physiological compression (greater stasis) were more likely to be associated with LIC. Materials and methods: In this HIPAA-compliant and IRB-approved study, we retrospectively reviewed clinical records and MRI for consecutive patients undergoing evaluation of venous malformations at our multidisciplinary Birthmarks and Vascular Anomalies Center between 2003 and 2013. Inclusion required consensus diagnosis of venous malformation and availability of laboratory data and MRI; patients on anticoagulation or those previously undergoing surgical or endovascular treatment were excluded. LIC was diagnosed when D-dimer exceeded 1,000 ng/mL and/or fibrinogen was less than 200 mg/dL. Two board-certified radiologists assessed the following MRI features for each lesion: morphology (spongiform vs. phlebectatic), presence of phleboliths, size, location (truncal vs. extremity), and tissue type(s) involved (subcutis, muscle, bone and viscera). Univariate logistic regression analyses were used to test associations between LIC and MRI findings, and stepwise regression was applied to assess the significance of the individual imaging predictors. Results: Seventy patients, 37 with LIC, met inclusion criteria during the 10-year study period (age: 14.5 +/- 13.6 years [mean +/- standard deviation]; 30 male, 40 female). Both elevated D-dimer and low fibrinogen were associated with the presence of phleboliths, larger lesion sizes and visceral involvement on MRI (all P < 0.05). In stepwise regressions, lesion size (P < 0.001), the presence of phleboliths (P = 0.005) and lesion morphology (P = 0.006) were all significant predictors of LIC. Conclusion: LIC is associated with larger lesion size, visualized phleboliths, truncal location and spongiform morphology on MRI in venous malformations, suggesting that lesions with larger capacitance, slower flow and less physiological compression are more likely to be associated with coagulopathy.

Objective: Compare the cost of performing an osteoid osteoma ablation using cone beam CT (CBCT) with overlay fluoroscopic guidance to ablation using conventional CT (CCT) guidance and microwave ablation (MWA) to radiofrequency ablation (RFA)., Methods: An 11-year retrospective study was performed of all patients undergoing osteoid osteoma ablation. Ablation equipment included a Cool tip RFA probe (Covidien, Minneapolis, Minnesota) or a Neuwave PR MWA probe (Ethicon, Rariton, New Jersey). The room times as well as immediate recovery time were recorded for each case. Cost analysis was then performed using time-driven activity-based costing for rate-dependent variables including salaries, equipment depreciation, room time, and certain supplies. Time-independent costs included the disposable interventional radiology supplies and ablation systems. Costs were reported for each service providing care and using conventional cost accounting methods with variable and fixed expenditures., Results: A total of 91 patients underwent 96 ablation procedures in either CBCT (n = 66) or CCT (n = 30) using either MWA (n = 51) or RFA (n = 45). The anesthesia induction (22.7 ± 8.7 min versus 15.9 ± 7.2 min, P < .001), procedure (64.7 ± 27.5 min versus 47.3 ± 15.3 min; P = .001), and room times (137.7 ± 33.7 min versus 103.9 ± 22.6. min; P < .001) were significantly longer for CBCT procedures. The procedure time did not differ significantly between MWA and RFA (62.1 ± 27.4 min versus 56.1 ± 23.3 min; P = .27). Multiple regression analysis demonstrated lower age (P = .046), CBCT use (P = .001), RFA use (P = .02), and nonsupine patient position (P = .01) significantly increased the total procedural cost. After controlling for these variables, the total cost of CBCT ($5,981.32 ± $523.93 versus $5,378.93 ± $453.12; P = .001) remained higher than CCT and the total cost of RFA ($5,981.32 ± $523.93 versus $5,674.43 ± $549.14; P = .05) approached a higher cost than MWA., Conclusion: The use of CBCT with overlay fluoroscopic guidance for osteoid osteoma ablation resulted in longer in-room times and greater cost when compared with CCT. These cost considerations should be weighed against potential radiation dose advantage of CBCT when choosing an image guidance modality. Younger age, RFA use, and nonsupine patient position additionally contributed to higher costs., (Copyright © 2023 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

The purpose of this study was to compare the adverse event (AE) rates of percutaneous pediatric transplant liver biopsies in patients receiving periprocedural antithrombotic agents with those in patients not receiving them. A 19-year retrospective single-center study of ultrasound-guided transplant liver biopsies was conducted. Patients who received aspirin for <5 days (n = 51) or heparin <4 hours (n = 15) before biopsy were separately grouped. AEs were reported using the Society of Interventional Radiology classification. In 276 biopsy samples from patients with a mean age of 6.75 years ± 5.80, the overall AE (P = .72) and moderate AE (P = .78) rates for control and antithrombotic groups were not significantly different. No severe AEs or deaths occurred. In conclusion, aspirin continuation during percutaneous pediatric transplant liver biopsies may be safe, but more studies are necessary to confirm the safety of periprocedural heparin., (Copyright © 2022 SIR. Published by Elsevier Inc. All rights reserved.)

Background: Portomesenteric and portosystemic venous occlusive disease may lead to portomesenteric hypertension, variceal bleeding, ascites and hypersplenism. Data regarding endovascular reconstructive strategies in children, however, are limited., Objective: To report technical success, outcome and patency of portomesenteric and portosystemic venous reconstruction using VIABAHN VBX balloon-expandable endoprostheses in pediatric patients., Materials and Methods: Five pediatric patients (median age: 15 years, range: 4-18 years), including 3 (60%) boys and 2 (40%) girls, with portomesenteric or portosystemic venous occlusion or recurrent stenosis, underwent balloon-expandable stent graft reconstruction. Presenting symptoms included acute variceal bleeding, without (n = 2, 40%) or with (n = 1, 20%) splenomegaly, and transfusion-dependent chronic melena (n = 1, 20%). One patient was asymptomatic (n = 1, 20%). Preprocedural imaging included Doppler ultrasound and contrast-enhanced computed tomography (CT) in all patients. Initial imaging showed 4 (80%) occlusions and 1 (20%) recurrent stenosis greater than 50%. Technical aspects of the reconstructions, technical successes, clinical outcomes and adverse events were recorded. Technical success was defined as completion of stent graft reconstruction. Adverse events were categorized according to Society of Interventional Radiology criteria. Clinical success was defined as resolution of the presenting symptoms and/or prevention of portal hypertensive sequela., Results: Venous reconstruction was technically successful in all five patients. Stent graft locations included the main portal vein in 2 (40%), the superior mesenteric vein in 1 (20%), autologous Meso-Rex shunt in 1 (20%) and splenocaval shunt in 1 (20%). Six stent grafts were placed (two stent grafts placed in a single patient). Stent grafts had a median diameter of 7 mm (range: 6-10 mm) and a median length of 59 mm (range: 19-79 mm). Median fluoroscopy time was 36.6 min (range: 13.4-95.8 min) and median air kerma was 301.0 mGy (range: 218.0-1,148.2 mGy). No adverse events occurred. Median clinical follow-up was 18 months (range: 6-29 months). Median imaging follow-up was 17 months (range: 2-29 months). Clinical success was achieved in all patients and maintained during the follow-up period. One patient required follow-up intervention with superior mesenteric vein side extension with a self-expanding bare metal stent due to perigraft stenosis detected on CT 3 months after stent placement. There were no stent graft occlusions., Conclusion: Portomesenteric and portosystemic venous reconstruction using balloon-expandable stent grafts in pediatric patients was feasible and clinically successful in this preliminary experience. Additional studies are warranted., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In pediatric liver transplantation, bile duct complications occur with a greater incidence than vascular anastomotic dysfunction and represent a major source of morbidity and mortality. While surgical re-anastomosis can reduce the need for retransplantation, interventional radiology offers minimally invasive and graft-saving therapies. The combination of small patient size and prevailing Roux-en-Y biliary enteric anastomotic techniques makes endoscopic retrograde cholangiopancreatography difficult if not impossible. Expertise in percutaneous management is therefore imperative. This article describes post-surgical anatomy, pathophysiology and noninvasive imaging of biliary complications. We review percutaneous techniques, focusing heavily on biliary access and interventions for reduced liver grafts. Subsequently we review the results and adverse events of these procedures and describe conditions that masquerade as biliary obstruction., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: To compare the direct bundled costs of interventional radiology (IR) suite versus bedside placement of noncuffed central venous catheters in infants., Methods: A single-center retrospective review was performed of all noncuffed upper extremity (peripherally inserted central venous catheter [PICC]) and tunneled femoral (tunneled femoral central venous catheter [TCVC]) catheters placed in infants between January 1, 2018, and December 31, 2018. Propensity score matching was performed adjusting for age, birth weight, procedure weight, and catheter days. Process maps for each procedure were created based on location and sedation type. Technical success and complications were recorded for each placement. The total direct bundled cost for each catheter placement was calculated by summing the procedure and complication costs., Results: A total of 142 procedures were performed on 126 matched patients with a technical success of 96% at the bedside and 100% in the IR suite (P = .08). The complication rates did not significantly differ between the 2 groups (P = .51). The total direct bundled costs for catheter placement were $1421.3 ± 2213.2 at the bedside and $2256.8 ± 3264.7 in the IR suite (P = .001)., Conclusions: The bundled cost of bedside femoral catheter placement is significantly less than that of fluoroscopic TCVC and PICC placement performed in the IR suite, mainly related to differences in sedation costs., (Copyright © 2021 SIR. Published by Elsevier Inc. All rights reserved.)

Background: Retrospective studies have demonstrated the efficacy and safety of pediatric and adolescent transjugular intrahepatic portosystemic shunt (TIPS), but long-term outcomes warrant further investigation., Objective: To report on the development of hyperplastic hepatic nodular lesion development in children and young adults (<21 years) with TIPS patency >3 years., Materials and Methods: Eighteen children and young adults, including 10 (55.6%) females and 8 (44.4%) males, underwent TIPS creation with >3 years' patency and follow-up evaluation at a tertiary children's hospital. The mean age at the time of TIPS creation was 12.5±5.1 years (range: 1.5-20.0 years). The mean model for end-stage liver disease (MELD) at the time of TIPS creation was 8.1±1.6 (range: 6-11). Indications for TIPS creation included acute variceal bleeding (8/18, 44.4%), primary (1/18, 5.6%) or secondary (7/18, 38.9%) prevention of varices, portal vein thrombosis (1/18, 5.6%), and splenic sequestration (1/18, 5.6%). Technical successes, intra-procedural parameters, hemodynamic and clinical successes, TIPS patencies, adverse events, imaging evaluations, and follow-ups were recorded., Results: All (100%) TIPS placements were successful; however, a direct intrahepatic portosystemic shunt was created in one (5.6%) patient. Mean reduction of the portosystemic shunt gradient was 9.1±3.3 mmHg (range: 4-16 mmHg). Seventeen (94.4%) patients demonstrated clinical success with resolution of their initial clinical indication for TIPS placement. The 3-year TIPS primary, primary-assisted, and secondary patencies were 83.3% (15/18), 94.4% (17/18), and 100% (18/18), respectively. Two (11.1%) patients developed mild, medically controlled hepatic encephalopathy. One (5.6%) patient developed hepatopulmonary syndrome. Nine (50%) patients developed single or multiple hepatic nodules at a mean imaging surveillance time after TIPS of 4.4±3.0 years (range: 1.5-10.2 years). Six (33.3%) patients developed nodules >1 cm with imaging features most consistent with focal nodular hyperplasia or focal nodular hyperplasia-like nodules. The mean follow-up duration was 5.7±2.9 years (range: 3.0-13.1 years)., Conclusion: Long-term (>3 years) portosystemic shunting via TIPS is associated with the development of hepatic nodular lesions in children. Consequently, children with TIPS may need gray-scale assessment of hepatic parenchyma as part of routine ultrasound exams and extended imaging surveillance until more is understood regarding the natural history of induced nodularity.

Background: Ultrasound (US)-guided tunneled femoral peripherally inserted central catheters (PICCs) are a safe central venous access option in infants and neonates. Studies have shown, however, that femoral central venous access has the potential for high central line-associated bloodstream infection (CLABSI) rates with a significant increase in risk around line day 30, though no studies have evaluated these risks exclusively for tunneled femoral PICCs., Objective: The primary purpose of this study was to evaluate the relationship between line duration and the risk of CLABSI in tunneled femoral PICCs in children., Materials and Methods: Four hundred forty-five patients (196 females, 249 males; median age: 49.4 days; median weight: 3.7 kg) who underwent 573 tunneled femoral PICC placements or exchanges from Jan. 1, 2017, to Jan. 31, 2020, were included in the study. All tunneled femoral PICCs were placed using US technique and catheter specifications, including catheter size (French) and length (cm), were retrieved from the electronic medical record. The location of the PICC placement, the number of lumens, the laterality of placement, and the patient's age and weight were also recorded. Only non-mucosal barrier injury CLABSIs, according to the Centers for Disease Control and Prevention (CDC) definitions, were counted as CLABSI for this study. The number of central line days until a CLABSI event was analyzed with an accelerated failure time model using the exponential, Weibull, and log-normal distributions to determine the probability of a CLABSI over time, taking into consideration the recorded covariates., Results: Tunneled femoral PICC placements accounted for 14,855 line days, during which 20 non-mucosal barrier injury CLABSIs (CLABSI rate of 1.35 per 1,000 line days) occurred during the study period. The highest CLABSI rate occurred in PICCs placed in the neonatal intensive care unit (NICU) at 2.01 per 1,000 line days and the lowest occurred in PICCs placed in interventional radiology at 0.26 per 1,000 line days. Overall, PICCs placed outside of interventional radiology had a CLABSI rate of 1.72 per 1,000 line days. The CLABSI rate during the first 30 days a line was in situ was lower than the rate after 30 days (0.51 per 1,000 line days vs. 3.06 per 1,000 line days, respectively). Statistical modeling and hazard estimation using the Akaike information criterion corrected for small sample size (AICc)-average of log-normal, Weibull and exponential distributions demonstrate the daily risk of CLABSI rapidly increases from day 1 to day 30, with the risk remaining high for the duration of line days., Conclusion: While tunneled femoral PICCs are a relatively safe and effective central venous access alternative, the rate of CLABSI appears to rapidly increase with increasing line days until around day 30 and then remains high thereafter.

Background: Ultrasonography may reliably visualize both appropriately positioned and malpositioned femoral-approach catheter tips. Radiography may be used to confirm catheter tip position after placement, but its utility following intraprocedural ultrasound (US) catheter tip verification is unclear., Objectives: To report the utility of confirmatory radiographs after US-guided tunneled femoral central venous catheter (CVC) placements by interventional radiology in pediatric patients., Materials and Methods: A total of 484 pediatric patients underwent bedside US-guided tunneled femoral CVC placements in an intensive care setting at a single tertiary children's hospital between Jan. 1, 2016, and April 20, 2020. Technical success, adverse events, post-procedure radiographic practices and inter-modality catheter tip concordance were recorded. All radiographs were performed within 12 h of catheter placement., Results: The mean patient age was 175±508 days (range: 1 day to 19 years), including 257 (53.1%) males and 227 (46.9%) females. Of the 484 attempted placements, 472 (97.5%) were primary placements. Four hundred eighty-one (99.4%) placements were technically successful. There were three (0.6%) technical failures due to previously undiagnosed iliofemoral venous occlusive disease. Five (1.0%) adverse events occurred. Radiographs were obtained within 12 h of CVC placement in 171 (35.3%) patients, in 120 (70.2%) of whom the indication was recent catheter placement. All 171 (100%) post-placement radiographs showed catheter tip location concordance with the intra-procedural US. In one (0.2%) patient, in whom there was nonvisualization of a guidewire and clinical concern for malposition during US-guided placement, post-procedure radiographs, coupled with multiplanar venography, demonstrated inadvertent paravertebral venous plexus catheter placement., Conclusion: The concordance between intra-procedural US and confirmatory post-procedure radiographs of CVC placements by interventional radiology obviates the need for routine radiographs. Radiographs may be obtained in instances of proceduralist uncertainty or clinical concern.

Background: The safety and efficacy of US-guided lumbar puncture in children has been described. In the pediatric setting, children are frequently referred to interventional radiology only after a failed landmark-based attempt. Routine pre-procedure US in these children is useful to determine a safe level for subarachnoid access and to optimize success., Objective: To determine whether pre-procedure US improves technical success and safety of US-guided lumbar puncture., Materials and Methods: We included 47 children. Inclusion criteria were urgent US-guided lumbar puncture in pediatric patients <18 years old. Exclusion criteria were non-urgent lumbar punctures, children referred without an antecedent landmark-based attempt, lumbar punctures performed with fluoroscopic guidance, and procedures performed prior to introducing the diagnostic approach in 2017. We did not evaluate data pertaining to successful landmark-based lumbar punctures performed without subsequent need for additional attempts. We recorded technical successes, adverse events and relevant abnormalities identified on pre-procedural US., Results: Thirty-six US-guided lumbar punctures were performed with 100% technical success. Eleven children referred to interventional radiology did not undergo lumbar puncture because of unfavorable US findings or interval clinical improvement obviating the need for lumbar puncture. Thirty-six children underwent US evaluation of the thecal sac prior to potential intervention. Of these 36 with pre-procedural US studies, 12 demonstrated paucity of cerebrospinal fluid and 14 demonstrated an epidural hematoma. Fifteen children who underwent lumbar puncture had a "traumatic tap," classified as a mild adverse event. No moderate or severe adverse events were recorded., Conclusion: Limited spinal US following failed landmark-based lumbar punctures frequently identifies procedure-related complications and can augment patient selection for future image-guided lumbar punctures.

OBJECTIVE. This article reviews the ultrasound characteristics of pediatric slow-flow vascular malformations and underscores findings that significantly impact diagnosis and treatment. Key imaging features are discussed including lesion size, malformation location, morphology, and mimics. CONCLUSION. Ultrasound findings affect the management of slow-flow vascular malformations and should be emphasized in lesion diagnosis. Superficial, focal lesions with well-defined margins are ideal for ultrasound evaluation.

Background: Nusinersen is the only approved treatment for all spinal muscular atrophy (SMA) subtypes and is delivered intrathecally. Distorted spinal anatomy and instrumentation preclude standard approaches for intrathecal access, necessitating alternative techniques for delivery. The purpose of this study is to report technical success and adverse events of transforaminal intrathecal delivery of nusinersen., Methods: 28 patients, mean age 24.1±9.8 years (range 10.0-51.0 years), with intermediate or late onset SMA, underwent a combined 200 transforaminal nusinersen injections. All patients had osseous fusion or spinal instrumentation precluding standard posterior access routes. Patients who underwent nusinersen injections using a technique other than transforaminal lumbar puncture (n=113) were excluded. Technical success, adverse events (AEs) and radiation exposure were recorded., Results: 200 (100%) procedures were technically successful; 6 (3%) required a second level of attempt for access. 187 (93.5%) interventions were completed using cone beam computed tomography (CBCT) with two-axis fluoroscopic navigational overlay. 13 (6.5%) procedures were performed with fluoroscopic-guidance only at subsequent sessions. There were 8 (4.0%) mild AEs and 2 (0.5%) severe AEs; one patient received antibiotics for possible traversal of the large bowel but did not develop meningitis, and one patient developed aseptic meningitis. Mean air kerma was 74.5±161.3 mGy (range 5.2-1693.0 mGy)., Conclusion: Transforaminal intrathecal delivery of nusinersen is feasible and safe for gaining access in patients with distorted spinal anatomy. The use of CBCT delineates anatomy and optimizes needle trajectory during the initial encounter, and may be used selectively for subsequent procedures., Competing Interests: Competing interests: EJM discloses scientific advisory and speaking for Biogen, Inc. NN receives research support for studies for Biogen, Inc., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Accurate and reproducible means of measuring the portosystemic gradient are essential for risk stratification and treatment of portal hypertension., Objective: To report the reliability of hepatic venous pressure gradients in children with intrahepatic veno-venous collateralization., Materials and Methods: Between January 2012 and December 2019 (96 months), 39 patients with native livers underwent wedge hepatic venography and hepatic venous pressure gradient measurements at a tertiary pediatric center. All archived images were reviewed for balloon isolation of the hepatic vein and hepatic vein-to-hepatic vein (HV-HV) collaterals. HV-HV collaterals were categorized as present on the basis of non-catheterized segmental venous opacification despite appropriate balloon isolation. Hepatic venous pressure gradient was defined as the difference of wedge and free hepatic venous pressures. Wedge portosystemic gradient was defined as the difference between wedge hepatic venous pressure and right atrial (RA) pressures. For patients subsequently undergoing portal venous catheterization, portosystemic gradient was defined as the difference between main portal vein and RA pressures., Results: Thirteen of 39 (33.3%) patients demonstrated HV-HV collaterals on wedge hepatic venography. The mean hepatic venous pressure gradient was 5.2±3.8 mmHg (range: 0-15 mmHg). The mean hepatic venous pressure gradient was 3.6±2.6 mmHg (range: 0-9 mmHg) in the presence of HV-HV collaterals and 5.9±4.2 mmHg (range: 1-15 mmHg) in the absence of HV-HV collaterals (P=0.043). Twelve (30.8%) patients were found to have varices: 10 gastroesophageal, 1 rectal and 1 stomal. The mean hepatic venous pressure gradient in patients with varices was 5.4±47 mmHg (range: 0-15 mmHg). For patients with varices, mean hepatic venous pressure gradient was 3.0±2.7 mmHg (range: 0-9 mmHg) in the presence of HV-HV collaterals and 10.3±4.1 mmHg (range: 5-15 mmHg) in the absence of HV-HV collaterals (P=0.004). Four (10.3%) patients had extrahepatic portal vein occlusion: 3 with cavernous transformation and 1 with type Ib Abernethy malformation. All patients with extrahepatic portal vein occlusion demonstrated HV-HV collaterals compared with 8 of 35 (22.9%) patients without extrahepatic portal vein occlusion (P=0.002). Four of 39 (10.3%) patients underwent direct portal pressure measurements: 3 via transhepatic and 1 via trans-splenic portal access. All had demonstrated HV-HV collaterals on wedged imaging. One had extrahepatic portal vein occlusion. The mean time between wedge portosystemic gradient and portosystemic gradient measurement was 3.75 days (range: 0-8 days). The mean wedge portosystemic gradient was 4.5±3.1 mmHg (range: 2-9 mmHg) and the mean portosystemic gradient was 14.5±3.7 mmHg (range: 12-20 mmHg) (P=0.006)., Conclusion: HV-HV collateralization is frequently observed in children undergoing wedged portal venography and leads to misrepresentative hepatic venous pressure gradients. All patients undergoing hepatic venous pressure gradient measurement should have wedged venography to identify HV-HV collaterals and to qualify measured pressures. Additional techniques to obtain representative pressures in the presence of HV-HV collaterals warrant further investigation.

Background: Published data describing the endovascular treatment of dysfunctional mesoportal and portosystemic shunts in the pediatric population are limited., Objective: We sought to describe the treatment and follow-up of such shunts managed by interventional radiology at a single pediatric hospital. We hypothesized that stenotic and occluded pediatric portosystemic and mesoportal shunts can be maintained patent by interventional radiology in the moderate term., Materials and Methods: We conducted a single-center retrospective study at a tertiary pediatric hospital. We included children with surgical mesoportal (meso-Rex) or portosystemic (mesocaval, splenorenal or splenocaval) shunts treated with attempted angioplasty or stenting from 2010 to 2018. Technical success was defined as catheterization and intervention upon the shunt with venographic evidence of flow improvement. The primary outcome variables were shunt patency at 1 month, 6 months, 12 months and 24 months post-procedure and freedom from reintervention., Results: Twenty pediatric patients (11 boys, 9 girls; mean age 8.25 years, range 1.3-17 years) met inclusion criteria. Fifty-two interventions (primary and reintervention) on 13 splenorenal, 3 meso-Rex, 2 mesocaval and 2 splenocaval shunts were performed because of evidence of shunt failure, including gastrointestinal bleeding, hypersplenism, or radiographic evidence of a flow defect. The 11 stenotic shunts were treated with 100% technical success, while the remaining 9 occluded shunts were treated with 66.7% technical success. The mean number of reinterventions was 1.9 (standard deviation [SD] = 3.1) per child, which did not differ between stenotic and occluded shunts (P=0.24). Primary patency at 1-month, 6-month, 12-month and 24-months follow-up visits was 17/17 (100%), 10/16 (62.5%), 7/15 (46.7%) and 4/10 (40%), respectively. However, 100% of shunts were either primary patent or primary-assisted patent by endovascular reintervention. There were no cases of shunt occlusion following initial technical success. Finally, the median freedom from reintervention duration was 387 days (SD=821 days)., Conclusion: Dysfunctional portosystemic surgical shunts are effectively managed by endovascular methods. While many shunts require reintervention, combined primary patency and assisted primary patency rates are excellent.

Background: The use of arterial closure devices in achieving femoral hemostasis has been well documented in adults but insufficiently studied in the pediatric population. An earlier study from our institution of 40 Angio-Seal devices in 38 patients concluded that the arterial closure device is safe in children with only a single minor complication. Ongoing experience with this device at our institution, however, suggests a higher rate of complication., Objective: To retrospectively evaluate the safety and efficacy of the Angio-Seal in a pediatric population., Materials and Methods: A retrospective analysis reviewed all cases in which the Angio-Seal was deployed from June 2011 to September 2017. Peri-procedural documentation was reviewed for pre-procedure labs, clinical effectiveness in achieving hemostasis and complications related to the use of this device. Logistic regression analysis was also used to evaluate the relationship between patient demographic, vessel size and indication for angiography, and the presence or absence of complications., Results: During the study period, 48 additional Angio-Seal devices were deployed in 41 consecutive patients. Five patients were excluded for being older than 18 years. The mean age of the patients was 13.3 years (range: 4-18 years) with 18 patients female. The mean common femoral artery diameter was 5.98 mm in short axis diameter (range: 4-9 mm). Complications were present in 6/43 cases (14%) including 3 minor and 3 major complications that included additional procedures. No significant relationship was identified between vessel size, age and the indication for angiography, and the rate of complication on logistic regression analysis., Conclusion: While percutaneous arterial closure devices can be efficacious for achieving hemostasis, our experience demonstrates a higher rate of complications in children, contrary to a previous report. The deployment of such devices should be performed with prejudice in this population.

Background: Image-guided percutaneous microwave ablation has been used to treat adult osteoid osteomas but has not been thoroughly evaluated in the pediatric population., Objective: To evaluate the technical feasibility and clinical efficacy of microwave ablation to treat osteoid osteomas in pediatric patients., Materials and Methods: The electronic medical record and imaging archive were reviewed for 24 consecutive patients who had undergone microwave ablation of osteoid osteomas between January 1, 2015, and May 31, 2018, at a single tertiary care pediatric hospital. All patients were diagnosed by clinical and imaging criteria, and referred by a pediatric orthopedic surgeon after failing conservative management with pain medication. The average age of the patients was 13.3 years (range: 3-18 years), and the average size of the osteoid osteoma nidus was 8.8 mm (range: 5-22 mm). Technical success was defined as placement of the microwave antenna at the distal margin of the lesion nidus and achievement of the target ablation temperature. Clinical findings were assessed pre- and post-ablation and clinical success was defined as complete relief of pain without pain medication at 1-month follow-up. The number and severity of complications were also documented., Results: Clinical success was achieved in 100% of patients (24/24), with all reporting complete cessation of pain medication use 1 week after treatment and 0/10 pain at 1 month. There were 4 minor complications (17%) including access site numbness and a minor soft-tissue infection. There were no major complications., Conclusion: Microwave ablation is a technically feasible and clinically effective treatment for pediatric osteoid osteomas.

Background: Cone-beam CT is increasingly used in pediatric interventional radiology procedures. However, the feasibility or safety of using this mode of imaging guidance for percutaneous lung nodule biopsy in children has not been assessed., Objective: To retrospectively evaluate safety and diagnostic accuracy of percutaneous lung nodule biopsy in people treated at a pediatric hospital using cone-beam CT with navigational overlay., Materials and Methods: Thirty-six consecutive patients from two large tertiary-care children's hospitals with lung nodules of 48 mm or smaller underwent percutaneous lung nodule biopsy using cone-beam CT with navigational overlay. We evaluated patient demographics, pre- and post-biopsy diagnoses, number of biopsy passes, complications, radiation exposure and technical success., Results: Percutaneous lung nodule biopsy was performed for 37 nodules in 36 patients (23 males, 13 females, median age 15.5 years, range 8 months to 23 years). One patient underwent biopsy of two nodules at a single procedure. Median patient weight was 55 kg (range 8-97 kg). Pre-biopsy diagnoses included metastatic sarcoma or other solid tumor (n=11), leukemia/lymphoma (n=13), infection (n=10), chronic granulomatous disease (n=2) and post-transplant lymphoproliferative disorder (PTLD; n=1). Mean number of passes was 5 (range 2-15). Mean pre-procedure international normalized ratio (INR) was 1.1 and platelet count 193 × 10 9 /L. Diagnostic specimens were obtained in 32 of 36 patients (89%). Thirteen complications were encountered in 12 patients (33% of cohort), including 9 pneumothoraces (4 requiring chest tubes); 1 hemothorax, which required a chest tube; and 3 self-limited pulmonary hemorrhages. Mean and median radiation doses were as follows: fluoroscopy time 3 min and 2.4 min, dose-area product (DAP) (recorded in 31 patients) 23,402 Gy·cm 2 and 12,453 Gy·cm 2 , and air kerma 88 mGy and 58 mGy., Conclusion: Percutaneous lung nodule needle biopsy can be performed accurately using cone-beam CT with navigational overlay.

Objective: To investigate Doppler US and catheter venogram correlates to improve detection of transplant HVOO and avoid unnecessary invasive imaging procedures., Materials and Methods: A retrospective review was performed in all pediatric OLT patients undergoing catheter venography of the hepatic veins between 2007 and 2017 at a single large tertiary pediatric liver transplant institution., Results: Forty-four transplant hepatic venograms in 32 OLT patients were included (mean 1.38, range 1-4 venograms per patient). All venograms were preceded by an independent Doppler US examination. Twenty-one (47.7%) venograms were performed for the investigation of suspected HVOO based on Doppler US alone, 19 (43.2%) were performed for TJLB without suspected HVOO, 4 (9.1%) were performed for both. Sixteen (36.3%) instances of >50% anastomotic stenosis were identified. Mean peak anastomotic velocities were 208 cm/s and 116 cm/s in the presence and absence of a >50% venographic stenosis, respectively (P < 0.004). In all cases where there was a monophasic waveform seen on Doppler US, there was a > 50% stenosis seen on hepatic vein venogram. In all cases where a triphasic waveform was seen on Doppler US, there was no stenosis seen on hepatic vein venogram., Conclusion: While a Doppler US velocity threshold providing both high sensitivity and specificity has yet to be identified, increasing peak anastomotic velocity and decreasing intrahepatic venous velocity correlate strongly with venographic outflow stenosis. The presence of a triphasic intrahepatic waveform provides good NPV., (© 2018 Wiley Periodicals, Inc.)

Purpose: To describe safety and efficacy of catheter-directed thrombolysis (CDT) for portal vein thrombosis (PVT) in children., Materials and Methods: Retrospective review was performed of 10 consecutive patients (7 girls, 3 boys; mean age 11.9 y; range, 3-17 y) with PVT undergoing CDT at a single tertiary children's hospital between August 2005 and March 2016. PVT was categorized by etiology and extent (intrahepatic, extrahepatic, or both). CDT was performed with infusion catheters placed via percutaneous transhepatic (PTH) and/or transjugular intrahepatic (TJ) approaches, with or without the use of adjunctive maneuvers, including balloon maceration and suction and rheolytic thrombectomy. Degree of thrombolysis on portal venography, presence of portal vein thrombus on available follow-up imaging, and complication rates were recorded., Results: In 10 patients, 13 CDT procedures were performed for PVT, with 3 patients requiring repeat CDT. Portal access was achieved with PTH (n = 6), TJ (n = 2), or combined (n = 2) approaches. All cases were successful in re-establishing patency and hepatopetal flow on portal venography with complete thrombolysis achieved in 10 of 13 cases (77%). Two major complications (20%) occurred, both with PTH access. Mean follow-up time for 9 patients was 2.6 years (range, 51-1,902 d) with long-term patency achieved in 6 (67%)., Conclusions: CDT can be safe and effective for PVT in children. Portal access considerations and early initiation of thrombolysis may further increase safety and efficacy., (Copyright © 2018 SIR. Published by Elsevier Inc. All rights reserved.)

An 11-year-old male with vasculitis was found to have a large abdominal aortic pseudoaneurysm on diagnostic angiography. This report describes endovascular repair of the pseudoaneurysm by stent-graft exclusion. The existing literature surrounding this rare and potentially fatal condition is also reviewed.

Background: Data regarding transsplenic portal venous access for diagnostic imaging and endovascular intervention in children are limited, possibly due to concerns regarding high bleeding risks and resultant underutilization., Objective: To investigate the safety and utility of transsplenic splenoportography and portal venous interventions in children., Materials and Methods: A retrospective review was performed of all pediatric patients undergoing percutaneous transsplenic portal venous access and intervention at two large tertiary pediatric institutions between January 2012 and April 2017 was performed. Parameters assessed included procedural indications, procedural and relevant prior imaging, technical details of the procedures, laboratory values and clinical follow-up., Results: Transsplenic portal venous access was achieved in all patients. Diagnostic transsplenic splenoportography was performed in 22 patients and was 100% successful at providing the desired anatomical and functional information. Four transsplenic portal venous interventions were performed with 100% success: meso-Rex shunt angioplasty, snare targeted transjugular intrahepatic portosystemic shunt (TIPS) creation through cavernous transformation, pharmacomechanical thrombectomy for acute thrombosis, and transplant portal vein angioplasty. Intraperitoneal bleeding occurred in 2/26 (7.7%) and one case required transfusion (3.8%). No cases of hemorrhage were observed when transsplenic access size was 4 Fr or smaller., Conclusion: Transsplenic splenoportography in children is safe and effective when noninvasive imaging methods have yielded incomplete information. Additionally, a transsplenic approach has advantages for complex portal interventions. Bleeding risks are proportional to tract access size and may be mitigated by tract embolization.

Purpose: Few established criteria exist to prompt angiographic evaluation and intervention for surgically created splenorenal shunts (SRS). Clinical and Doppler ultrasound (DUS) imaging predictors of shunt dysfunction were evaluated in this retrospective study., Materials and Methods: Consecutive patients undergoing SRS angiography over a 10-year period were retrospectively identified. Preangiography platelet count and DUS measurements of spleen diameter, maximum splenic vein velocity, and maximum shunt velocity were assessed and compared to findings at subsequent catheter angiography., Results: Twenty-six SRS angiograms were performed in 16 patients. Two of the 26 procedures were excluded from analysis due to insufficient baseline preangiography clinical and DUS data. In the remaining 24 cases, significant stenosis/occlusion was confirmed at angiography in 20, whereas wide patency was seen in 4. For the 20 cases of angiographically confirmed significant stenosis/occlusion, when compared to baseline post-SRS creation to immediate preangiography evaluation there was a greater decrease in platelet count (-51.8% vs -19.4%), a greater increase in spleen diameter (+13.4% vs +3.7%), a greater increase in maximum shunt velocity (+74.7% vs +59.7%), and a greater decrease in splenic vein velocity (-25.0% vs -18.5%)., Conclusion: Clinical evidence of splenic sequestration and DUS finding of increased maximum shunt velocity correlate with angiographic findings of SRS dysfunction and could be used to help predict the need for shunt intervention.

Background: Disadvantages of fluoroscopically guided lumbar puncture include delivery of ionizing radiation and limited resolution of incompletely ossified posterior elements. Ultrasound (US) allows visualization of critical soft tissues and the cerebrospinal fluid (CSF) space without ionizing radiation., Objective: To determine the technical success and safety of US-guided lumbar puncture in pediatric patients., Materials and Methods: A retrospective review identified all patients referred to interventional radiology for lumbar puncture between June 2010 and June 2017. Patients who underwent lumbar puncture with fluoroscopic guidance alone were excluded. For the remaining procedures, technical success and procedural complications were assessed. Two hundred and one image-guided lumbar punctures in 161 patients were included. Eighty patients (43%) had previously failed landmark-based attempts., Results: One hundred ninety-six (97.5%) patients underwent lumbar puncture. Five procedures (2.5%) were not attempted after US assessment, either due to a paucity of CSF or unsafe window for needle placement. Technical success was achieved in 187 (95.4%) of lumbar punctures attempted with US guidance. One hundred seventy-seven (90.3%) were technically successful with US alone (age range: 2 days-15 years, weight range: 1.9-53.1 kg) and an additional 10 (5.1%) were successful with US-guided thecal access and subsequent fluoroscopic confirmation. Three (1.5%) cases were unsuccessful with US guidance but were subsequently successful with fluoroscopic guidance. Of the 80 previously failed landmark-based lumbar punctures, 77 (96.3%) were successful with US guidance alone. There were no reported complications., Conclusion: US guidance is safe and effective for lumbar punctures and has specific advantages over fluoroscopy in pediatric patients.

The purpose of the article is to evaluate the effects of mechanical complications, such as clogging or coiling, of gastrojejunostomy tubes on radiation exposure during exchange in the pediatric population. In this HIPAA-compliant and IRB-approved study, we retrospectively reviewed procedural records for patients undergoing gastrojejunostomy (GJ) tube exchange during a 4-month period in 2014. Success of the procedure, specifications of the tube, age, and sex of the patient as well as radiation exposure during the procedure were included. Radiation exposure was measured in fluoroscopy time and cumulative air kerma. Complications encountered during exchange were also recorded, if available. Patients presenting for gastrostomy to GJ conversions or combined procedures were excluded from the study. Ordinary and mixed effect linear regression models were used to test associations between GJ tube parameters, presence of mechanical complications, and fluoroscopy time and radiation dose. 146 patients undergoing 285 GJ exchanges met inclusion criteria over the 4-month study period (M:F 82:64). All exchanges were successful with 85 demonstrating a form of mechanical complication (44 coiled, 41 clogged). Of the reported GJ tube specifications, only tube length was significantly associated with mechanical complications (p < 0.001). The presence of mechanical complication was significantly associated with increased radiation exposure and fluoroscopy time (p < 0.0001). Mechanical complications of gastrojejunostomy tubes, such as clogging or coiling, are associated with increased radiation exposure during exchange. Strategies to decrease these complications, including re-siting the gastrostomy tract or placement of a surgical jejunostomy in the event of repeated coiling of a tube should be strongly considered.

Background: Nusinersen, the only treatment approved by the United States Food and Drug Administration for spinal muscular atrophy (SMA), is delivered intrathecally. Many children with SMA have extensive spinal instrumentation and deformities, often precluding the use of standard approaches for gaining intrathecal access. Furthermore the anatomical distortion that often occurs with rotoscoliosis can complicate the use of fluoroscopic guidance. Compared to fluoroscopy, CT affords superior guidance for complex needle placements. This opens up alternatives to the posterior (interlaminar) technique, including transforaminal and caudal approaches., Objective: This study describes the early results of technical success, complications and radiation dose of intrathecal delivery of nusinersen using cone-beam CT guidance with two-axis fluoroscopic navigational overlay., Materials and Methods: We conducted a retrospective review of 15 consecutive nusinersen injections performed in four children with SMA and extensive spinal hardware precluding standard posterior lumbar puncture techniques. These children were treated using transforaminal thecal access employing cone-beam CT with navigational overlay. We analyzed results including technical success, complications and total fluoroscopy time., Results: All procedures were technically successful. No major complications and one minor complication were reported; the minor complication was a post-procedural neuropathic headache that was attributed to procedural positioning and was treated successfully with gabapentin. The average procedural fluoroscopy time and air kerma were 1.9 min and 55.8 mGy, respectively., Conclusion: Cone-beam CT guidance with two-axis navigational overlay is a safe, effective method for gaining transforaminal intrathecal access in children with spinal abnormalities and hardware precluding the use of standard techniques.

Background: The purpose of this study was to evaluate safety, technical success, and clinical outcomes of treatment for venous malformations using n -BCA glue embolization immediately prior to excision. Sixty three patients (22 male, 41 female; mean age 12 years (range 1-25)) who underwent 70 procedures for extremity and trunk venous malformations were reviewed. Indications for treatment included pain (100%), swelling (22%), and diminished range of motion (16%). Thirty seven patients (59%) had undergone prior stand-alone interventional or surgical treatment but were persistently symptomatic. Safety, technical and clinical success were retrospectively assessed., Results: Embolization was technically successful in 100% of patients. Mean lesion size was 3.0 × 2.9 × 5.7 cm. Three patients (5%) underwent planned, second stage procedures for lesions intentionally not treated at the first procedure. Four patients (6%) underwent an unplanned, second stage procedure for residual disease after the primary operation. Mean and median follow-up duration were 18 and 17 months, respectively (range 3 to 35 months). Symptomatic improvement was achieved in 58 patients (92%), of whom 41 (65%) reported complete elimination of pain. There were no recognized instances of nontarget embolization or other complications of the interventional procedure. One patient required additional surgery for wound dehiscence and one patient developed an abscess requiring incision and drainage. Minor surgical complications included surgical site skin infections ( n  = 5) and numbness ( n  = 1). Mean and median surgical blood loss volumes were 131 mL and 10 mL, respectively. One patient required perioperative blood transfusion., Conclusions: Extremity and truncal venous malformations can be safely and effectively treated in a single-stage fashion using glue embolization immediately preceding excision., Competing Interests: Obtained prior to performing study.Obtained.The authors declare that they have no competing interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Introduction: We report what is to the best of our knowledge the second adult case of chylothorax clearly associated with severe hypothyroidism in the English-language medical literature. To the best of our knowledge, this is the first case of its kind reported without a prior history of malignancy., Case Presentation: A 37-year-old Hispanic woman with no reported significant past medical history initially presented with shortness of breath and inability to lose weight. She was found to have a large chylous effusion requiring chest-tube drainage, as well as severe hypothyroidism. After several weeks of thyroid hormone-replacement therapy, the formation of chylous pleural fluid in the patient greatly diminished, and the chest tube was removed. Upon long-term follow-up her minimal residual effusion remains stable on serial chest radiographs., Conclusion: Although the exact pathophysiologic relation between low thyroid hormone levels and chyle formation remains to be elucidated, hypothyroidism should be a diagnostic consideration in patients with chylous effusions, especially those refractory to conventional treatments.