Percutaneous biopsy for the diagnosis, risk stratification, and molecular profiling of neuroblastoma: A single-center retrospective study

PURPOSE

To determine whether percutaneous core needle biopsy (PCNB) is adequate for the diagnosis and full molecular characterization of newly diagnosed neuroblastoma.

MATERIALS AND METHODS

Patients with newly diagnosed neuroblastoma who underwent PCNB in interventional radiology at a single center over a 5-year period were included. Pre-procedure imaging and procedure details were reviewed. Rates of diagnostic success and sufficiency for International Neuroblastoma Pathology Classification (INPC), risk stratification, and evaluation of genomic markers utilized in the Children's Oncology Group risk stratification, and status of the anaplastic lymphoma kinase (ALK) gene were assessed.

RESULTS

Thirty-five patients (13 females, median age 2.4 years [interquartile range, IQR: 0.9-4.4] and median weight 12.4 kg [IQR: 9.6-18]) were included. Most had International Neuroblastoma Risk Group Stage M disease (n = 22, 63%). Median longest axis of tumor target was 8.8 cm [IQR: 6.1-12]. A 16-gauge biopsy instrument was most often used (n = 20, 57%), with a median of 20 cores [IQR: 13-23] obtained. Twenty-five specimens were assessed for adequacy, and 14 procedures utilized contrast-enhanced ultrasound guidance. There were two post-procedure bleeds (5.7%). Thirty-four of 35 procedures (97%) were sufficient for histopathologic diagnosis and risk stratification, 94% (n = 32) were sufficient for INPC, and 85% (n = 29) were sufficient for complete molecular characterization, including ALK testing. Biologic information was otherwise obtained from bone marrow (4/34, 12%) or surgery (1/34, 2.9%). The number of cores did not differ between patients with sufficient versus insufficient biopsies.

CONCLUSION

In this study, obtaining multiple cores with PCNB resulted in a high rate of diagnosis and successful molecular profiling for neuroblastoma.

Endovascular closure of a congenital extrahepatic portosystemic shunt for the treatment of hepatopulmonary syndrome in an infant

Congenital portosystemic shunts may result in the development of hepatopulmonary syndrome, typically presenting with progressive hypoxemia in later childhood. We describe a case of a 5-month-old male with heterotaxy with polysplenia presenting with new onset hypoxemia. Subsequent evaluation identified an extrahepatic portosystemic shunt arising from the confluence of the main portal and superior mesenteric veins draining into the left renal vein. To treat his hypoxemia and prevent future complications of shunting, the patient underwent a successful single-stage endovascular closure.

Embolization for pediatric trauma

BACKGROUND

The management of pediatric trauma with trans-arterial embolization is uncommon, even in level 1 trauma centers; hence, there is a dearth of literature on this subject compared to the adult experience.

OBJECTIVE

To describe a single-center, level 1 trauma center experience with arterial embolization for pediatric trauma.

MATERIALS AND METHODS

A retrospective review was performed to identify demographics, transfusion requirements, pre-procedure imaging, procedural details, adverse events, and arterial embolization outcomes over a 19-year period. Twenty children (age 4.5 months to 17 years, median 13.5 years; weight 3.6 to 108 kg, median 53 kg) were included. Technical success was defined as angiographic resolution of the bleeding-related abnormality on post-embolization angiography or successful empiric embolization in the absence of an angiographic finding. Clinical success was defined as not requiring additional intervention after embolization.

RESULTS

Seventy-five percent (n=15/20) of patients required red blood cell transfusions prior to embolization with a mean volume replacement 64 ml/kg (range 12-166 ml/kg) and the median time from injury to intervention was 3 days (range 0-16 days). Technical success was achieved in 100% (20/20) of children while clinical success was achieved in 80% (n=16/20). For the 4 children (20%) with continued bleeding following initial embolization, 2 underwent repeat embolization, 1 underwent surgery, and 1 underwent repeat embolization and surgery. Mortality prior to discharge was 15% (n=3). A post-embolization mild adverse event included one groin hematoma, while a severe adverse event included one common iliac artery pseudoaneurysm requiring open surgical ligation.

CONCLUSIONS

In this single-center experience, arterial embolization for hemorrhage control in children after trauma is feasible but can be challenging and the clinical failure rate of 20% in this series reflects this complexity. Standardization of pre-embolization trauma assessment parameters and embolic techniques may improve outcomes.

Novel method to biopsy aneurysmal bone cysts in children

PURPOSE

The thin and friable septations composing aneurysmal bone cysts (ABC) may be challenging to target for percutaneous biopsy. The purpose of this study was to describe and evaluate a novel method of ABC biopsy using endomyocardial biopsy forceps as an attempt to capture larger fragments of tissue for diagnosis.

METHODS AND MATERIALS

This was a retrospective study performed over a 17-year period. Patients <18 years old who underwent percutaneous biopsy for a presumed ABC, based on pre-procedure imaging, were included. Medical records were reviewed to identify age, sex, lesion location, biopsy procedure details, complications, and pathology results. A diagnostic biopsy was defined as conclusive histologic confirmation. Inconclusive findings or findings suggestive of but not diagnostic of an ABC were treated as non-diagnostic, even if imaging and clinical findings were characteristic. Biopsy device selection and quantity of tissue obtained was at the discretion of the pediatric interventional radiologist. Fisher's exact test was used to compare the diagnostic yield of standard biopsies to those employing biopsy forceps.

RESULTS

Twenty-three biopsies were performed in 18 patients (11 female) with a median age of 14.7 years (IQR 10.6-15.6). Lesions were located in the extremities (7, 30.4%), chest (6, 26.1%), pelvis (5, 21.7%), spine (4, 17.4%), and mandible (1, 4.3%). Specimens were obtained using a 13- or 15-gauge bone coring needle (11, 47.8%); 14-, 16-, or 18-gauge soft tissue needle (6, 26.1%); or a combination of bone and soft tissue (4, 17.4%) needles. Endomyocardial biopsy forceps were utilized in 7 cases (30.4%), 2 in which it was the only device used. Overall, a conclusive pathologic diagnosis was made in 13/23 (56.5%) biopsies. Of the diagnostic biopsies, 1 was a unicameral bone cyst and all others were ABCs. No malignancy was identified. Compared to the standard approach, the use of forceps was more likely to result in a diagnostic biopsy (40.0% vs 100.0%, p = 0.008). There were no complications.

CONCLUSIONS

Endomyocardial biopsy forceps offer an additional, novel technique to biopsy presumed ABCs and may improve diagnostic yield.

Middle meningeal artery embolization in the management of chronic subdural hematoma in medically complex pediatric neurosurgical patients: technical note

Middle meningeal artery (MMA) embolization has gained acceptance as a treatment for chronic subdural hematoma (cSDH) in adult patients but has not been well described in pediatric patients. Standard cSDH treatment has historically consisted of burr hole drainage with or without subdural drain placement. However, due to the high rate of recurrence and frequency of comorbidities within this population, as both pediatric and adult patients with cSDH frequently have concurrent cardiac disease and a need for anticoagulant therapies, MMA embolization has increasingly demonstrated its value as both an adjunctive and primary treatment. In this report, the authors present 3 cases of successful MMA embolization in medically complex children at a single institution. MMA embolization was used as a primary treatment modality and as an adjunctive therapy in the acute setting following surgical hematoma evacuation. Two patients were receiving anticoagulation treatment requiring reversal. Technical considerations specific to the pediatric population as well as those common to both the pediatric and adult populations are addressed. Further work is needed to define the optimal indications and outcomes for MMA embolization in children with cSDH.

Fostering research in pediatric interventional radiology: needs assessment and suggestions for support

BACKGROUND

Due to the rarity of pediatric diseases, collaborative research is the key to maximizing the impact of research studies. A research needs assessment survey was created to support initiatives to foster pediatric interventional radiology research.

OBJECTIVE

To assess the status of pediatric interventional radiology research, identify perceived barriers, obtain community input on areas of research/education/support, and create metrics for evaluating changes/responses to programmatic initiatives.

MATERIALS AND METHODS

A survey link was sent to approximately 275 members of the Society for Pediatric Interventional Radiology (SPIR) between May and October 2020. Data was collected using a web-based interface. Data collected included practice setting, clinical role, research experience, research barriers, and suggestions for future initiatives.

RESULTS

Fifty-nine surveys were analyzed with a staff physician survey response rate of 28% (56/198). A wide range of practice sizes from 15 countries were represented. Respondents were predominantly staff physicians (95%; 56/59) with an average of 11 years (range: 1-25 years) of clinical experience working at academic or freestanding children's hospitals. A total of 100% (59/59) had research experience, and 70% (41/58) had published research with a mean of 30 peer-reviewed publications (range: 1-200). For job security, 56% (33/59) of respondents were expected or required to publish, but only 19% (11/58) had research support staff, and 42% (25/59) had protected research time, but of those, 36% (9/25) got the time "sometimes or never." Lack of support staff, established collaborative processes, and education were identified as top barriers to performing research.

CONCLUSIONS

The needs assessment survey demonstrated active research output despite several identified barriers. There is a widespread interest within the pediatric interventional radiology community for collaborative research.

Percutaneous Nephrostomy in Neonates and Young Infants

PURPOSE

To describe a single-center experience of placing percutaneous nephrostomy (PCN) tubes in neonates and young infants aged ≤3 months.

MATERIALS AND METHODS

This retrospective study evaluated PCN placement during a 19-year period. Medical records were reviewed for patient demographics, indications, procedure details, catheter-related adverse events, and outcomes. A total of 45 primary PCN insertions were attempted in 29 children (median age, 11 days [range, first day of life to 3 months]; median weight, 3.5 kg [range, 1.4-7.0 kg]). Salvage procedures resulted in 13 secondary catheters in 6 children. The most common indication was ureteropelvic junction obstruction (40.0%), and the most common urinary tract dilation classification was P3 (88.9%).

RESULTS

Technical success for primary placements was 95.6%; both technical failures were due to loss of access in the same patient. Of primary placements, 76.7% were electively removed, 6.9% were dislodged but not replaced, and the remaining 16.3% required salvage procedures. Mechanical adverse events occurred in 20.9% of primary and 53.8% of secondary catheters, including partial retraction, complete dislodgement, and occlusion. Urinary tract infections (UTIs) occurred in 18.6% of primary and 15.4% of secondary catheters. Urosepsis occurred in 2.3% of primary and 7.7% of secondary catheters. Median primary catheter dwell time was 41 days (range, 1-182 days) and median secondary catheter dwell time was 31 days (range, 10-107 days).

CONCLUSION

PCN placement in neonates and young infants has a high technical success rate, although not without particular procedural and management challenges of catheter malfunction and UTI.

Genomic profiling informs diagnoses and treatment in vascular anomalies

Vascular anomalies are malformations or tumors of the blood or lymphatic vasculature and can be life-threatening. Although molecularly targeted therapies can be life-saving, identification of the molecular etiology is often impeded by lack of accessibility to affected tissue samples, mosaicism or insufficient sequencing depth. In a cohort of 356 participants with vascular anomalies, including 104 with primary complex lymphatic anomalies (pCLAs), DNA from CD31+ cells isolated from lymphatic fluid or cell-free DNA from lymphatic fluid or plasma underwent ultra-deep sequencing thereby uncovering pathogenic somatic variants down to a variant allele fraction of 0.15%. A molecular diagnosis, including previously undescribed genetic causes, was obtained in 41% of participants with pCLAs and 72% of participants with other vascular malformations, leading to a new medical therapy for 63% (43/69) of participants and resulting in improvement in 63% (35/55) of participants on therapy. Taken together, these data support the development of liquid biopsy-based diagnostic techniques to identify previously undescribed genotype-phenotype associations and guide medical therapy in individuals with vascular anomalies.

Central venous access in children: Placement trends over the last decade

PURPOSE

To evaluate central venous access placement trends for radiology and non-radiology services over the last decade.

MATERIALS AND METHODS

Children who had central venous access procedures included in a large administrative database of 49 pediatric institutions in the United States between 2010 and 2020 were included. Patient demographics and patient specific factors were compared between groups. The percentage of procedures performed by interventional radiology (IR) and non-radiology services were compared over time and by region.

RESULTS

A total of 483,181 vascular access encounters were recorded (45.3% female; median age 2 years (IQR 0-11 years)). Approximately one quarter of vascular access encounters were IR-led, with a slight increase of 3.8% between 2010 and 2020. Children who underwent IR-placed vascular access were older (median age of 4 years compared to 1 year in non-radiology encounters). Interventional radiology-placed access was greatest in the Midwest (33.5%) with a decrease of 5.9% over the study period; in the other three regions, IR-performed encounters increased. Patient comorbidities more prevalent in the IR encounters were technology dependence (42.4% of all radiology encounters), gastrointestinal (34.9%), respiratory (20.8%), and transplant (8.1%), while those which were more prevalent in the non-radiology encounters were nephrology/urology (21.4% of all non-radiology encounters), prematurity/neonatal (17.3%), and malignancy (17.3%).

CONCLUSIONS

Interventional radiology-provided vascular access services have slightly increased over the last decade without significant service-line transfer to other specialties. Underlying comorbidities in IR-led vascular access encounters vary across institutions based on referral patterns, possibly reflecting the adoption of ultrasound guidance by other pediatric subspecialties.

Large scalp venous malformation in a pediatric patient managed with sclerotherapy and surgery: a case report and review of literature

BACKGROUND

Venous malformations (VMs) are slow-flow vascular anomalies present at birth that enlarge during adolescence, subsequently causing thrombosis, hemorrhage, and pain.

CASE PRESENTATION

We describe a case of an adolescent male presenting with a large scalp venous malformation. Given the size and location of the lesion, a hybrid approach employing both sclerotherapy and surgical resection was utilized. The VM was successfully removed without complication.

CONCLUSION

A hybrid approach is a safe and effective treatment consideration for immediate management of large venous malformation in higher-risk locations.

Indeterminate Thyroid Fine-Needle Aspirations in Pediatrics: Exploring Clinicopathologic Features and Utility of Molecular Profiling

INTRODUCTION

The diagnostic utility of molecular profiling for the evaluation of indeterminate pediatric thyroid nodules is unclear. We aimed to assess pediatric cases with indeterminate thyroid fine-needle aspiration (FNA) alongside clinicopathologic features and mutational analysis.

METHODS

A retrospective review of 126 patients with indeterminate cytology who underwent FNA between January 2010 and December 2021 at the Children's Hospital of Philadelphia was performed. Indeterminate cases defined by The Bethesda System for Reporting Thyroid Cytopathology (AUS/FLUS or TBSRTC III; FN/SFN or TBSRTC IV; SM or TBSRTC V) were correlated to clinicopathologic and genetic characteristics.

RESULTS

Of the 114 surgical cases, 48% were malignant, with the majority of malignant cases diagnosed as follicular variant of papillary thyroid carcinoma (28/55). Risk of malignancy increased with TBSRTC category: 23% for AUS/FLUS, 51% for FN/SFN, and 100% for SM nodules. There were significant differences in surgical approach (p < 0.01), performance of lymph node dissection (p < 0.01), histological diagnosis (p < 0.01), primary tumor focality/laterality (p = 0.04), and lymphatic invasion (p = 0.02) based on TBSRTC classification, with resultant differences in post-surgical risk stratification per American Thyroid Association (ATA) Pediatric Guidelines (p = 0.01). Approximately 89% (49/55) of cases were classified as ATA low risk, and 5 of 6 patients with ATA intermediate- or high-risk disease had SM cytology. Somatic molecular testing was performed in 40% (51/126) of tumors; 77% (27/35) of malignant cases and 38% (6/16) of benign cases harbored driver alteration(s). Of the driver-positive malignant cases, 52% (14/27) were associated with low risk (DICER1, PTEN, RAS, and TSHR mutations), 33% (9/27) were associated with high risk (BRAF mutations and ALK, NTRK, and RET fusions), and 15% (4/27) had unreported risk for invasive disease (APC, BLM, and PPM1D mutations and TG-FGFR1 fusion). Incidence of high-risk drivers increased with TBSRTC category. Approximately 23% (8/35) of patients harboring thyroid malignancy did not have an identifiable driver alteration.

CONCLUSIONS

Molecular analysis is useful to discriminate benign and malignant thyroid nodules with indeterminate cytology. Patients with driver genetic alteration(s) and indeterminate cytology should consider surgical management secondary to the high incidence (82%; 27/33) of thyroid malignancy in these patients.

Appendix to the Society of Interventional Radiology Consensus Guidelines for the Periprocedural Management of Thrombotic and Bleeding Risk in Patients Undergoing Percutaneous Image-Guided Interventions: Pediatric Considerations

PURPOSE

To provide guidance on the use of anticoagulant and antithrombotic agents in pediatric patients undergoing interventional radiology procedures.

MATERIALS AND METHODS

A multidisciplinary writing group conducted a comprehensive literature search to identify studies on the topic of interest. Recommendations were developed for procedural risk and medication dosage and withholding. A modified Delphi technique was used to achieve consensus agreement on the recommendations.

RESULTS

A total of 24 studies, including systematic reviews and meta-analyses, randomized controlled trials, and prospective and retrospective cohort studies, were identified as relevant. The expert writing group agreed on procedural risk categorization, laboratory testing thresholds, and medication dosage and withholding recommendations specific to pediatric practice. They additionally described the nuances of anticoagulation in clinical conditions specific to pediatrics.

CONCLUSIONS

The Society of Interventional Radiology recommends following the guidance provided in the document when developing multidisciplinary management protocols for anticoagulation and antithrombotic treatment in pediatric patients undergoing interventional radiology procedures.

Bowel perforation following percutaneous sclerotherapy of an intra-abdominal lymphatic malformation

Mesenteric lymphatic malformations result from abnormal proliferation of disorganized mesenteric lymphatic channels. Sclerotherapy is often preferred over surgery as it is less invasive and has lower post-procedure morbidity. Sclerotherapy has been described as durable and effective with a low complication rate. We describe a serious complication from sclerotherapy of a lymphatic malformation extending from the mesentery through the bowel wall, highlighting the spectrum of this pathology and the need for multidisciplinary management of complex cases.

Pediatric trauma and the role of the interventional radiologist

PURPOSE

While interventional radiologists occupy a critical role in adult trauma management, the role of interventionalist in pediatric trauma continues to evolve. The indications for transarterial embolization (TAE) are significantly different in pediatric patients in whom non-operative management (NOM) has a much more prominent role than in adults. Contrast extravasation on imaging may not require acute surgical or interventional management as it would in an adult. There are also areas in which pediatric interventional radiology is increasingly useful such as pelvic TAE in failed management, or splenic embolization to treat bleeding without the loss of splenic function inherent to surgical splenectomy. The rapid evolution of techniques and devices in pediatric patients is also changing what interventions are possible in pediatric trauma management which necessitates frequent reassessment of the guidelines and interventional radiology's role in caring for these patients.

CONCLUSION

This review seeks to consolidate the recent literature to describe the evolving role of the interventional radiologist in pediatric trauma management.

Validation of computed tomography angiography as a complementary test in the assessment of renal artery stenosis: a comparison with digital subtraction angiography

BACKGROUND

Renal artery stenosis is an important cause of hypertension in children, accounting for 5-10% of cases. When suspected, noninvasive imaging options include ultrasound (US), computed tomography (CT) angiography and magnetic resonance (MR) angiography. However, digital subtraction angiography (DSA) remains the gold standard.

OBJECTIVE

To investigate the accuracy and inter-reader reliability of CT angiography in children with suspected renal artery stenosis.

MATERIALS AND METHODS

This is a retrospective study of patients suspected of having renal artery stenosis evaluated by both CT angiography and DSA between 2008 and 2019 at a tertiary pediatric hospital. Only children who underwent CT angiography within 6 months before DSA were included. CT angiography studies were individually reviewed by two pediatric radiologists, blinded to clinical data, other studies and each other's evaluation, to determine the presence of stenosis at the main renal artery and 2nd- and 3rd-order branches. The sensitivity, specificity and accuracy were calculated using DSA as the reference. The effective radiation dose for CT angiography and DSA was also calculated. Kappa statistics were used to assess inter-reader agreement.

RESULTS

Seventy-four renal units were evaluated (18 girls, 19 boys). The patients' median age was 8 years (range: 1-21 years). Overall, CT angiography was effective in detecting renal artery stenosis with a sensitivity of 85.7%, specificity of 91.5% and accuracy of 88.9%. There was moderate inter-reader agreement at the main renal artery level (k=0.73) and almost perfect inter-reader agreement at the 2nd/3rd order (k=0.98). However, the sensitivity at the 2nd- and 3rd-order level was lower (14.3%). CT angiography provided excellent negative predictive value for evaluating renal artery stenosis at the main renal artery level (90.1%) and at the 2nd- or 3rd-order branches (82.7%). The median effective dose of CT angiography studies was 2.2 mSv (range: 0.6-6.3) while the effective dose of DSA was 13.7 mSv.

CONCLUSION

CT angiography has high sensitivity and specificity at the main renal artery level with a lower radiation dose than previously assumed. Therefore, it can be used as a diagnostic tool in patients with low to medium risk of renal artery stenosis, and as a screening and treatment planning tool in patients at high risk.

Coil-Localized Laparoscopic-Assisted Resection of Symptomatic Gastrointestinal Vascular Malformations in Children and Young Adults

Gastrointestinal (GI) bleeding from pediatric vascular malformation is uncommon and difficult to diagnose and manage. The preferred treatment is surgical resection; however, it can be challenging to precisely localize the lesion, particularly if it is not serosal.

Objectives

To describe a technique of intentional preoperative coil localization of symptomatic pediatric GI vascular malformations by pediatric interventional radiology to facilitate fluoroscopically assisted laparoscopic resection.

Methods

We searched the electronic privacy information center and picture archive and communication system in our center and found 3 cases. The electronic privacy information center and picture archive and communication system databases were the sources for retrieval of demographic, medical, radiological, and procedural information in all 3 cases.

Results

After many nondiagnostic investigations in all 3 patients, a GI vascular malformation as a cause of GI bleeding was diagnosed with computed tomography angiography/magnetic resonance angiography and catheter angiography. A preoperative 0.018-inch Hilal coil was placed as close as possible to the vascular malformation during super selective angiography. Laparoscopic surgery was performed within 24 hours of coil placement. In all cases, histology confirmed the resected bowel lesions to be vascular malformations.

Conclusions

Intentional endovascular coil localization has the potential to increase the precision of lesion localization and may reduce laparoscopic operative time, when guided by the coil position.

Balloon occlusion as an adjunctive technique during sclerotherapy of Puig's classified advanced venous malformations

OBJECTIVE

Puig types 2 through 4 venous malformations (VMs) are challenging to treat with sclerotherapy given their robust systemic outflow. Endovenous balloon occlusion offers a means of temporarily occluding systemic venous outflow to allow for more complete sclerotherapy. This study reviews our experience of implementing this technique in patients with Puig advanced (types 2 through 4) VMs.

METHODS

An IRB approved review of treated venous malformations from 2013-2016 revealed 10 patients fitting inclusion criteria. Patient demographics, pre-procedural imaging, intra-procedural technical parameters, and post-procedural follow-up outcomes were recorded. All patients underwent temporary balloon occlusion of a systemic or major draining vein during sclerotherapy. Embolic agents included n-butyl cyanoacrylate glue, sodium tetradecyl sulfate foam, and coils. Standard 5 French angioplasty balloons ranged from 4 to 8 mm diameter and 2 to 8 cm length depending on vessel requiring occlusion. All patients underwent minimum 3-year follow-up questionnaire administration re-assessing resolution of lesion symptomology and post-procedural quality of life (QoL) measures.

RESULTS

Of the 10 VMs treated, 2 were Type 2, 6 were Type 3, and 2 were Type 4. More than one sclerotherapy session was required in 7/10 patients (mean: 2, range: 1-4). Most common sites of VM systemic drainage included subclavian, popliteal, internal/external jugular, and basilic veins. All patients had no indication for further sclerotherapy following adjunctive balloon occlusion. No non-target embolization or immediate post-procedural complications occurred. Follow-up questionnaires (mean interval: 3 years 6 months, range: 3 years-3 years 11 months) confirmed the persistence of embolization effects, improved QoL, and no additional sclerotherapy sessions for all patients in the cohort.

CONCLUSIONS

Endovenous balloon occlusion as an adjunct to sclerotherapy can be considered when treating patients with types 2-4 venous malformations. This technique lowers the risk of non-target systemic venous embolization, allowing for operator-driven deeper intralesional sclerosant penetration and subsequently maintained treatment efficacy.

A new syndrome of moyamoya disease, kidney dysplasia, aminotransferase elevation, and skin disease associated with de novo variants in RNF213

Ring‐finger protein 213 (RNF213) encodes a protein of unknown function believed to play a role in cellular metabolism and angiogenesis. Gene variants are associated with susceptibility to moyamoya disease. Here, we describe two children with moyamoya disease who also demonstrated kidney disease, elevated aminotransferases, and recurrent skin lesions found by exome sequencing to have de novo missense variants in RNF213. These cases highlight the ability of RNF213 to cause Mendelian moyamoya disease in addition to acting as a genetic susceptibility locus. The cases also suggest a new, multi‐organ RNF213‐spectrum disease characterized by liver, skin, and kidney pathology in addition to severe moyamoya disease caused by heterozygous, de novo C‐terminal RNF213 missense variants.

Pediatric May-Thurner Syndrome-Systematic review and individual patient data meta-analysis

BACKGROUND

The outcomes of deep vein thrombosis (DVT) in children with May-Thurner Syndrome (MTS) remain unclear.

OBJECTIVES

This systematic review and patient-level meta-analysis aims to describe the outcomes of children with MTS presenting with DVT.

METHODS

A systematic review of the published literature was performed. Data related to patients <18 years diagnosed with MTS and DVT was extracted. Risk of bias was assessed using the Murad criteria. Outcomes included vessel patency post-treatment, DVT recurrence, and post-thrombotic syndrome (PTS). Predictive and explanatory models were developed for these outcomes.

RESULTS

In total, 109 cases were identified (age range 4-17 years; 77 females) in 28 studies; 75% of patients had ≥1 additional risk factor for DVT. PTS was seen in 61% of patients, DVT recurrence in 38%, and complete vessel patency post-treatment in 65%. The models developed to predict and explain PTS performed poorly overall. Recurrent thrombosis (adjusted for age and patency) predicted PTS (odds ratio [OR] 3.36, 95% confidence interval [CI] 1.28-8.82). DVT management strategies (adjusted for age and DVT characteristics) predicted vessel patency (OR 2.10, 95% CI 1.43-3.08). Lack of complete vessel patency (adjusted for age and thrombophilia) predicted recurrent DVT (OR 2.70, 95% CI 1.09-6.67). Sensitivity analyses showed the same direction of effects for all outcomes.

CONCLUSIONS

PTS and DVT recurrence occur frequently in pediatric MTS. PTS prediction is complex and it was not possible to identify early predictors to guide clinical practice. Use of imaging-guided therapy and thrombus burden predicted venous patency, and lack of patency predicted DVT recurrence.

Central venous catheter fracture leading to TPN extravasation and abdominal compartment syndrome diagnosed with bedside contrast-enhanced ultrasound

Central venous lines may require contrast injection under fluoroscopy to evaluate for dysfunction such as occlusion, fibrin sheath development or catheter fracture. Rarely, some patients may be too ill to travel to the interventional radiology suite for this examination. We present a case utilizing contrast-enhanced ultrasound (CEUS) at the bedside to assess catheter integrity in a critically ill infant with a large intra-abdominal fluid collection. CEUS demonstrated extravasation into the collection, confirming catheter fracture and prompting immediate cessation of line use and recommendation for exchange. This case shows the utility of CEUS to evaluate central venous access devices in children who are unable to travel to interventional radiology for a standard contrast injection.

Image-Guided Biopsy for Relapsed Neuroblastoma: Focus on Safety, Adequacy for Genetic Sequencing, and Correlation of Tumor Cell Percent With Quantitative Lesion MIBG Uptake

PURPOSE

Many novel therapies for relapsed and refractory neuroblastoma require tumor tissue for genomic sequencing. We analyze our experience with image-guided biopsy in these patients, focusing on safety, yield, adequacy for next-generation sequencing (NGS), and correlation of tumor cell percent (TC%) with quantitative uptake on ¹²³I-meta-iodobenzylguanidine (MIBG) single-photon emission computed tomography with computed tomography (SPECT/CT).

MATERIALS AND METHODS

An 11-year retrospective review of image-guided biopsy on 66 patients (30 female), with a median age of 8.7 years (range, 0.9-49 years), who underwent 95 biopsies (55 bone and 40 soft tissue) of relapsed or refractory neuroblastoma lesions was performed.

RESULTS

There were seven minor complications (7%) and one major complication (1%). Neuroblastoma was detected in 88% of MIBG- or fluorodeoxyglucose-avid foci. The overall NGS adequacy was 69% (64% in bone and 74% in soft tissue, P = .37). NGS adequacy within neuroblastoma-positive biopsies was 88% (82% bone and 96% soft tissue, P = .11). NGS-adequate biopsies had a greater mean TC% than inadequates (51% v 18%, P = .03). NGS-adequate biopsies had a higher mean number of needle passes (7.5 v 3.4, P = .0002). The mean tissue volume from NGS-adequate soft-tissue lesions was 0.16 cm³ ± 0.12. Lesion:liver and lesion:psoas MIBG uptake ratios correlated with TC% (r = 0.74, r = 0.72, and n = 14). Mean TC% in NGS-adequate samples was 51%, corresponding to a lesion:liver ratio of 2.9 and a lesion:psoas ratio of 9.0. Thirty percent of biopsies showed an actionable ALK mutation or other therapeutically relevant variant.

CONCLUSION

Image-guided biopsy for relapsed or refractory neuroblastoma was safe and likely to provide NGS data to guide therapy decisions. A lesion:liver MIBG uptake ratio of ≥ 3 or a lesion:psoas ratio of > 9 was associated with a TC% sufficient to deliver NGS results.

Renovascular hypertension in children

Paediatric hypertension, defined as systolic blood pressure > 95th percentile for age, sex and height is often incidentally diagnosed. Renovascular hypertension (RVH) is responsible for 5-25% of hypertension in children. Renal artery stenosis and middle aortic syndrome can both can be associated with various conditions such as fibromuscular dysplasia, Williams syndrome & Neurofibromatosis type 1. This paper discusses the approaches to diagnosis and interventional management and outcomes of renovascular hypertension in children. Angiography is considered the gold standard in establishing the diagnosis of renovascular disease in children. Angioplasty is beneficial in the majority of patients and generally repeated angioplasty is considered more appropriate than stenting. Surgical options should first be considered before placing a stent unless there is an emergent requirement. Given the established safety and success of endovascular intervention, at most institutions it remains the preferred treatment option.

Implantable venous access devices in children with severe hemophilia: a tertiary pediatric institutional experience

BACKGROUND

Clotting factor replacement forms the pillar of treatment for children with hemophilia. Most children can be treated using peripheral venipuncture, but very young children and children with poor venous access might require a central venous catheter. Short-term and long-term complications of implantable venous access device placement (also known as port placement) can result in important morbidity and mortality in children with hemophilia.

OBJECTIVE

The purpose of this study is to describe our experience with port placement in children and adolescents with severe hemophilia (<1% of the Factors VIII or IX).

MATERIALS AND METHODS

We performed a retrospective review over a 10-year period to identify port placement in pediatric patients with severe hemophilia. We reviewed demographic and procedural information, access frequency, mechanical complications, and central-line-associated bloodstream infections (CLABSI). Eighteen males were included, with median age at insertion of 3.9 years (0.7-22.7 years). Fifteen of the 18 patients had hemophilia Type A and 3/18 had Type B. Thirteen had high neutralizing inhibitor titers.

RESULTS

Technical success in port placement was achieved in 26/27 (96.3%) patients, with 1 port failure caused by venous occlusion from prior catheter placement. Port catheter size ranged from 5 French (Fr) to 7.5 Fr. All were single-lumen and placed via right (76.9%) or left (23.1%) internal jugular vein; 59.3% were placed during general anesthesia, and all had factor replacement prophylaxis. A peripherally inserted central catheter (PICC) was placed concurrently in 69.2% of the cases; per hospital policy, the port was only accessed 15 days post-placement to reduce the risk of site hematoma. Two patients were lost to follow-up. The total catheter days was 15,893. Ports were removed in 14/24 cases, most commonly because of CLABSI (7/24; 29.2%) and transition to peripheral infusion (3/24; 12.5%). Bleeding was the most common complication in the first 30 days after placement. There were nine CLABSI events (0.57 per 1,000 catheter days), all in patients with high neutralizing inhibitor titers. A higher frequency of port access (more or equal to daily vs. less than daily) correlated with higher infection rates (P=0.02). Median time from port insertion to first infection was 348 days (range 167-1,055 days). There were four fibrin-sheath-related catheter occlusions (0.25 per 1,000 catheter days): three catheters were salvaged with intra-catheter tissue plasminogen activator (tPA) instillation resulting in a salvage of an additional 1,214 catheter days, and one catheter was removed after tPA failure (0.06 per 1,000 catheter days).

CONCLUSION

Port maintenance in boys with severe hemophilia is challenging given the need for long-term frequent device access that is associated with catheter-related infections. The rate of bleeding or infection did not differ in patients whether the device was accessed immediately or 15 days post placement. With appropriate pre- and post-procedural factor replacement, immediate and early term severe complications are not common.

Postpyloric Balloon Occlusion to Increase Technical Success during Pediatric Percutaneous Gastrostomy/Gastrojejunostomy Tube Placement

Gastric distension through insufflation is a key step in creating a safe percutaneous window during gastrostomy/gastrojejunostomy (G/GJ) placement; however, poor or incomplete gastric distention can occur, despite the use of glucagon, and lead to rapid egress of air from the stomach into the duodenum. This report describes the adjunctive technique using postpyloric balloon occlusion in 29 patients to maximize gastric insufflation during G/GJ tube placement after failure of conventional methods. Balloon occlusion was successful in salvaging 23 of 29 (79.3%) of G/GJ tube placements without any complications.

Image-guided core needle biopsy for relapsed and refractory neuroblastoma: A focus on sample adequacy for genetic sequencing

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Background: Relapsed and refractory neuroblastoma (NBL) is a prime target for novel therapies targeting specific mutations. The genomic landscape of NBL can change between time of initial diagnosis and relapse, necessitating subsequent biopsy and next generation sequencing (NGS) to detect mutations within the relapsed neoplasm. Tissue of insufficient quality and quantity leads to specimen failure during NGS. Thus the goal of this study is to review core needle biopsy for relapsed and refractory NBL in a pediatric interventional radiology department and explore factors that enhance biopsy adequacy. Methods: Retrospective review of clinical records and images for 66 patients (36M, 30F) with median age 8.7 years (range 0.9 – 49.3 y) who underwent 95 biopsies (55 bone, 40 soft tissue) over a 12-year period. Results: Biopsy yield for neuroblastic tissue from 123I mIBG-avid masses was 89.7% overall, 84.9% in bone, and 91.6% in soft tissue. 87/95 masses were mIBG-avid; 2 non-avid masses were NBL-positive (but also 18F-FDG avid). 48/59 samples sent for NGS were adequate for analysis (81.4%); bone and soft tissue biopsies did not differ in adequacy (77.1% vs 87.5%, p = 0.32). Tumor cell percent (TC%) for adequate samples was 49.9% vs 11.1% for NGS failures (p = 0.0003). Number of needle passes performed in bone and soft tissue lesions was positively correlated with NGS adequacy (Bone: r2= 0.68, Soft: r2= 0.33). In bone and soft tissue, adequate biopsies tended towards higher mean needle passes than inadequate ones (Bone: 5.1 vs 3.4, p = 0.0582) (Soft: 10.5 vs 4.7, p = 0.0428). Total needle volume passed into a soft tissue mass (calculated as inner needle cylindrical volume * # of passes) was higher in the “adequate” vs “inadequate” group (0.20 cm3 vs 0.05 cm3, p = 0.0004). Lesion mIBG avidity was quantified with a ratio of lesion:liver SUV; this mIBG SUV ratio was positively correlated with TC% (R2 = 0.55, N = 14). Using a linear regression line, a TC% of 50% (the mean value for samples adequate for NGS) corresponded to an SUV ratio of 2.89. The rate of minor complications (requiring only nominal therapy) was 7/95 (7.4%). The rate of major complications (requiring longer hospital stay) was 1/95 (1.5%). Conclusions: Image-guided core needle biopsy for relapsed and refractory NBL has a moderately high yield for procuring tumor samples adequate for NGS with a low rate of major complications. Adequate bone and soft tissue biopsies averaged >5 and >10 needle passes, respectively. An approximate lesion:liver mIBG SUV ratio of >3 may maximize specimen quality for NGS.

Pediatric Renovascular Hypertension: Manifestations and Management

Renovascular hypertension (RVHTN) is an important contributor to secondary etiologies of hypertension in the pediatric population. A delay in diagnosis can be associated with adverse outcomes. The etiologies of renal artery stenosis (RAS) vary from anatomical, inflammatory, genetic syndromes, intra-luminal, external compression and idiopathic. It is a silent disease with isolated hypertension as its primary clinical manifestation. Laboratory values can be notable for electrolyte derangements and renal dysfunction, but are not universally present. The diagnosis requires a high index of clinical suspicion and entails ruling out other secondary causes of hypertension while monitoring for target organ damage. Imaging of individuals with suspected RAS includes: renal ultrasound, computed tomography angiography, magnetic resonance angiography and renal scintigraphy, but angiography continues to be the gold standard. Various factors are used to determine the most appropriate method for ongoing care: anti-hypertensive therapy, with or without radiological or surgical intervention. In all instances, a multi-disciplinary team approach should be used to provide optimal care to these children and adolescents.

Segmental congenital hemangiomas: Three cases of a rare entity

Congenital hemangiomas (CHs) are unusual and diverse tumors distinguished from infantile hemangiomas by being largely developed at birth and glucose transporter (GLUT1)-negative. We describe three infants who presented in utero or at birth with segmentally distributed vascular tumors that were GLUT1-negative, had histology compatible with congenital hemangioma, and exhibited spontaneous clinical involution. One of the three patients had high-output cardiac failure and was found to have a mutation in GNAQ (c.626A>c, p.Gln209Pro); another had high-output cardiac failure, heterotaxy, and transient hematologic abnormalities and was found to have a mutation in GNA11 (c.626_627delinsCC, p.Gln209Pro). In addition to describing a novel segmental pattern of congenital hemangioma variant with genetic correlations, these cases illustrate the utility of targeted genetic testing to elucidate the exact mutation and thus classification of vascular tumors.

Association of intracranial arteriovenous malformation embolization with more rapid rate of perfusion in the peri-nidal region on color-coded quantitative digital subtraction angiography

BACKGROUND

Hemodynamic alterations post-embolization of intracranial arteriovenous malformations (AVMs) may cause delayed edema/hemorrhage in brain parenchyma adjacent to the lesion.

OBJECTIVE

To quantify and compare cerebral perfusion changes in the peri-AVM territory pre- and post-embolization using color-coded quantitative digital subtraction angiography (q-DSA).

METHODS

Pediatric intracranial AVM embolization procedures performed over a 5 year period were included. DSA images of all patients were retrospectively assessed using syngo iFlow. Regions of interest (ROI) were selected on anteroposterior and lateral q-DSA views: three in the peri-AVM region; two in parenchyma distant from the AVM. Time-to-peak (TTP) contrast enhancement of ROIs and ∆TTP (TTP at the selected ROI minus TTP at either the ipsilateral internal carotid/vertebral artery) were measured.

RESULT

19 pediatric patients with 19 AVMs (9 males/10 females, mean age 12 years) underwent intracranial AVM embolization: 15/19 AVMs were supplied by the anterior circulation and 4/19 by the posterior circulation. Blood flow was significantly slower post-embolization in the draining vein (19/19) (p<0.01), and the venous sinus outflow (17/19) (p<0.01), by mean difference of 2.01±1.31 s and 1.74±2.04 s. There was significantly increased peri-AVM parenchymal perfusion post-embolization (∆TTP=2.20±0.48 s) compared with pre-embolization (∆TTP=2.52±0.42 s), by an average ∆TTP of 0.33±0.53 s (p=0.014). In contrast, there was no perfusion difference (∆TTP=0.03±0.20 s, p=0.8) between pre- and post-embolization in the distant parenchyma. The size of the AVM was not correlated with change in peri-nidal parenchymal perfusion (r=-0.136, p=0.579).

CONCLUSION

This study demonstrates more rapid perfusion in the peri-nidal brain parenchyma post-embolization of the AVM, which supports the theory that increased perfusion in normal tissue surrounding the AVM after embolization may underlie some post-procedural complications.

New onset dysphagia and pulmonary aspiration following sclerotherapy for a complex cervical venolymphatic malformation in an infant: Case report and review of the literature

We present the case of a 2-year-old male with a complex left cervical venolymphatic malformation who underwent doxycycline sclerotherapy at 12 months of age complicated by new onset pulmonary aspiration. A review of the literature reveals this to be a rare complication of sclerotherapy and only the second reported case.

METHODS

Procedural details with associated imaging including endoscopic airway and swallowing evaluation are included. A literature review of cervical and laryngeal sclerotherapy complications was performed and discussed.

RESULTS

A 12-month-old male underwent sclerotherapy with doxycycline for a complex parapharyngeal and paralaryngeal venolymphatic malformation. The postoperative course was complicated by new onset dysphagia, aspiration, and decreased laryngeal sensation. Gastric feeding and swallowing therapy were necessary due to prolonged difficulty. The sclerotherapy treatment resulted in near elimination of the cervical components of the lesion at 12 months follow up. The child progressed to total oral feeding by 17 months post-treatment with no evidence of decreased laryngeal sensation. An extensive literature review identified only one reported case of new onset dysphagia and decreased laryngeal sensation after doxycycline sclerotherapy.

CONCLUSIONS

Doxycycline sclerotherapy for cervical venolymphatic malformations rarely can cause adjacent neural injury resulting in laryngeal complications. Our case report and literature review suggest that symptom management and appropriate aspiration precautions are necessary in infants or children with presumed vagus or laryngeal nerve injury, and injury is likely only temporary.

Percutaneous liver biopsy in Fontan patients

BACKGROUND

Patients who have undergone the Fontan operation for palliation of congenital heart disease with single-ventricle pathophysiology are at high risk for developing progressive liver fibrosis. Pathological assessment from percutaneous liver biopsy is central to the management of Fontan-associated liver disease, but liver biopsy in this vulnerable population poses unique challenges and potential risks.

OBJECTIVE

This retrospective study describes our experience with percutaneous liver biopsy performed to assess changes of Fontan-associated liver disease, with particular regard to procedural outcomes.

MATERIALS AND METHODS

Data from liver biopsy procedure reports, pathology reports, cardiac angiography pressure measurements and laboratory values of patients with single ventricle heart disease after the Fontan operation who underwent ultrasound-guided percutaneous liver biopsy performed in interventional radiology at a pediatric tertiary care center during a 3-year period were retrospectively analyzed.

RESULTS

Sixty-eight liver biopsies were performed in 67 patients (mean age: 20.2 years, range: 7.2-39 years). The technical success rate was 100%, and tissue was adequate for assessing liver disease in 100% of the procedures, including biopsies performed with a single pass. Anticoagulation was routinely suspended before biopsy, and no cardiac complications were encountered due to this suspension. A coaxial biopsy system using an 18-gauge (G) full-core instrument through a 17-G introducer trocar was most commonly used, in 41/68 cases (60%). The most common trough length was 2.3 cm, used in 37 cases (54%). One pass was made in 27 procedures (40%) and two passes in 30 (44%); tract embolization with gelatin sponge was performed in 52 (76%). The only complication was hemorrhage, which occurred in 5/68 (7.4%) of the biopsies, minor in four (5.9%) and major in one (1.5%) -- similar to rates reported for liver biopsy in non-Fontan patients. Hemorrhage had a delayed presentation in three of these five cases. Immediate post-biopsy hemoglobin decrease of ≥2 mg/dL showed a low sensitivity for hemorrhage. The mean Fontan pressure measured during cardiac angiography was 13.8 mmHg, and shunt pressures were not associated with an increased risk of hemorrhage.

CONCLUSION

Percutaneous liver biopsy in Fontan patients can be performed safely with high technical success rates and without increased complication rates. Meticulous technique and close observation are recommended to reduce post-biopsy complications. The degree of right heart pressure elevation was not associated with hemorrhage.

Methemoglobinemia in an Infant After Sclerotherapy With High-Dose Doxycycline

Methemoglobinemia occurs when the heme moiety of hemoglobin (Hb) is oxidized from the ferrous to ferric state, leading to impairments in oxygen transport and delivery. Methemoglobinemia is rare in pediatric patients but has been described in the setting of congenital abnormalities in the Hb structure, inherited enzyme deficiencies, oxidative Hb injury in response to illness, and oxidative Hb injury due to toxicants. We present a 1-week-old infant born with a cervical lymphangioma who developed persistent desaturations that were unresponsive to oxygen after sclerotherapy with doxycycline. Arterial blood gas revealed a high Pao₂ despite low saturations being found on pulse oximetry and a methemoglobin level that was found to be elevated. Further sclerotherapy was discontinued, the saturations eventually normalized, and the methemoglobin level decreased. This is a novel report of sclerotherapy with doxycycline associated with the development of methemoglobinemia.

Imaging studies in pediatric fibromuscular dysplasia (FMD): a single-center experience

BACKGROUND

Fibromuscular dysplasia (FMD) is a non-inflammatory vascular disease that in children unlike in adults shows no sex predilection. FMD is often underdiagnosed, and its pathophysiology is unclear. Delayed diagnosis may lead to refractory hypertension and decreases the chance of successful treatment. Doppler ultrasound (US), magnetic resonance angiography (MRA), computed tomography angiography (CTA), and catheter-based angiography (angiography) are currently used to help make a clinicoradiological diagnosis of FMD. The main aim of the study was to compare the efficacy of imaging modalities which can allow for earlier and improved detection. Furthermore, an anatomical mapping of the location of lesions can help determine the best treatment modalities.

METHODS

All patients with non-syndromic non-inflammatory renovascular hypertension were recruited from the Nephrology Department at the Children's Hospital of Philadelphia (CHOP) and enrolled in the U.S. FMD Registry maintained at the University of Michigan. Clinical presentation and imaging findings on US, CT, and MRI of children diagnosed with FMD were evaluated.

RESULTS

Mean age at diagnosis was 7 ± 4.9 years (4 months-17 years). Family history of hypertension (HTN) (52%), FMD (8.7%), Caucasian (60%), headache (48%), and HTN (80%) were the most prevalent symptom and sign at presentation. Bruits were 100% specific for renal artery stenosis (RAS) diagnosis but were heard in the minority of patients (3 patients, 12%). FMD was mainly unifocal within a single site (68%) or multiple sites (28%) and involved the main or first order renal branch in about 68% of children. Isolated distal lesions beyond the second order branches were found in about 25% of children. US imaging was significantly less sensitive than angiography (28%, p = 0.003). MRA had a better sensitivity (62.5%, p = 0.3) than US. Overall, CTA had the best sensitivity (84.2%, p = 0.4) compared to angiography; however, only angiography showed distal vessel disease.

CONCLUSIONS

Limitations of the study include the sample size and biases-only patients diagnosed with FMD were included in this study and most patients were referred to a pediatric nephrologist for unexplained hypertension. Angiography should be performed as part of the initial work-up of any child suspected of having renovascular FMD, regardless of the findings seen on US, MRA, or CTA.

Role of interventional radiology in managing pediatric liver tumors : Part 2: percutaneous interventions

Hepatoblastoma and hepatocellular carcinoma (HCC) are the most common pediatric liver malignancies, with hepatoblastoma occurring more commonly in younger children and HCC occurring more commonly in older children and adolescents. Although surgical resection (including transplant when necessary) and systemic chemotherapy have improved overall survival rate for hepatoblastoma to approximately 80% from 30%, a number of children with this tumor type are not eligible for operative treatment. In contradistinction, pediatric HCC continues to carry a dismal prognosis with an overall 5-year survival rate of 30%. The Paediatric Hepatic International Tumour Trial (PHITT) is an international trial aimed at evaluating both existing and emerging oncologic therapies for primary pediatric liver tumors. Interventional radiology offers a number of minimally invasive procedures that aid in diagnosis and therapy of pediatric liver tumors. For diagnosis, the PHITT biopsy guidelines emphasize and recommend percutaneous image-guided tumor biopsy. Additionally, both percutaneous and endovascular procedures provide therapeutic alternatives that have been, to this point, only minimally utilized in the pediatric population. Specifically, percutaneous ablation offers a number of cytotoxic technologies that can potentially eradicate disease or downstage children with unresectable disease. Percutaneous portal vein embolization is an additional minimally invasive procedure that might be useful to induce remnant liver hypertrophy prior to extended liver resection in the setting of a primary liver tumor. PHITT offers an opportunity to collect data from children treated with these emerging therapeutic options across the world. The purpose of this manuscript is to describe the potential role of minimally invasive percutaneous transhepatic procedures, as well as review the existing data largely stemming from the adult HCC experience.

Role of interventional radiology in managing pediatric liver tumors : Part 1: Endovascular interventions

Primary liver malignancies are rare in children. Hepatoblastoma and hepatocellular carcinoma (HCC) together represent the overwhelming majority of cases. Overall survival of hepatoblastoma approaches 80% with multimodal treatment approaches that include chemotherapy, surgery and transplantation. However, there remains a subset of children with hepatoblastoma in whom resection or transplantation is not possible. The 5-year survival for children diagnosed with HCC is less than 30% and remains a significant therapeutic challenge. The poor outcomes for children with primary liver tumors motivate investigation of new therapeutic alternatives. Interventional oncology offers a broad scope of percutaneous and transcatheter endovascular cancer therapies that might provide clinical benefits. Minimally invasive approaches are distinct from medical, surgical and radiation oncologic treatments, and in adults these approaches have been established as the fourth pillar of cancer care. Transarterial chemoembolization is a minimally invasive locoregional treatment option performed by interventional radiologists with level-I evidence as standard of care in adults with advanced liver malignancy; transarterial chemoembolization in adults has served to prolong disease-free progression, downstage and bridge patients for surgical and transplant interventions, and improve overall survival. However, while several groups have reported that transarterial chemoembolization is feasible in children, the published experience is limited primarily to small retrospective case series. The lack of prospective trial evidence has in part limited the utilization of transarterial chemoembolization in the pediatric patient population. The purpose of this article is to provide an overview of the role of interventional radiology in the diagnosis and endovascular management of hepatic malignancies in children.

Prospective evaluation of MR overlay on real-time fluoroscopy for percutaneous extremity biopsies of bone lesions visible on MRI but not on CT in children in the interventional radiology suite

Magnetic resonance imaging (MRI) often provides better visualization of bone marrow abnormalities than computed tomography (CT) or fluoroscopy, but bone biopsies are usually performed using conventional CT or, more recently, C-arm CT guidance. Biopsies of bone lesions solely visible on MRI are often challenging to localize and require the operator to review the MRI on a separate console to correlate with MRI anatomical landmarks during the biopsy. The MR overlay technique facilitates such biopsies in the angiographic suite by allowing the pre-procedural 3-D MRI to be overlaid on intraprocedural 2-D fluoroscopy. This study describes our initial experience with the MR overlay technique in the angiography suite during pediatric percutaneous extremity bone biopsies of lesions visible on MRI but not on CT or fluoroscopy and demonstrates its utility in relevant clinical cases.

Venous Ports in Infants

PURPOSE

To evaluate technical success and the incidences of, and risk factors for, mechanical and infectious complications of venous port placement in infants.

MATERIALS AND METHODS

This was a retrospective single-institution cohort study of port placement in infants (age < 1 y) from January 2006 through June 2016 (mean age, 7.5 mo ± 3.3; mean weight, 8.1 kg ± 1.9). Age, weight, sex, side of placement, tip position, and indication for placement (chemotherapy vs other) were recorded. Total catheter-days (CDs), mechanical complications, and central catheter-associated bloodstream infections (CCABSIs) were identified.

RESULTS

During the study years, 64 ports were placed in 64 infants, with a technical success rate of 100%. The mean catheter life was 321 days (total range, 4-1,917 d; interquartile range [IQR], 107-421 d). There were 13 CCABSI events (0.63 per 1,000 CDs); of these, 8 (12.5% among 64 patients) required port removal for infection. There was an increase in CCABSIs in patients with left-sided port placement (relative risk [RR], 3.22; 95% confidence interval [CI], 1.02-10.14; P = .05). There were 8 mechanical complications of the port reservoir or catheter (0.39 per 1,000 CDs). Of these, 2 (3.1%) required removal. Patients in the lowest weight quartile were at an increased risk of mechanical complications (RR, 4.37; 95% CI, 1.09-17.48; P = .04).

CONCLUSIONS

Venous ports can be placed with a high rate of technical success in infants. Left-sided ports and low weight are associated with increased infectious and mechanical complications, respectively.

Reduced-dose C-arm computed tomography applications at a pediatric institution

BACKGROUND

Reduced-dose C-arm computed tomography (CT) uses flat-panel detectors to acquire real-time 3-D images in the interventional radiology suite to assist with anatomical localization and procedure planning.

OBJECTIVE

To describe dose-reduction techniques for C-arm CT at a pediatric institution and to provide guidance for implementation.

MATERIALS AND METHODS

We conducted a 5-year retrospective study on procedures using an institution-specific reduced-dose protocol: 5 or 8 s Dyna Rotation, 248/396 projection images/acquisition and 0.1-0.17 μGy/projection dose at the detector with 0.3/0.6/0.9-mm copper (Cu) filtration. We categorized cases by procedure type and average patient age and calculated C-arm CT and total dose area product (DAP).

RESULTS

Two hundred twenty-two C-arm CT-guided procedures were performed with a dose-reduction protocol. The most common procedures were temporomandibular and sacroiliac joint injections (48.6%) and sclerotherapy (34.2%). C-arm CT was utilized in cases of difficult percutaneous access in less common applications such as cecostomy and gastrostomy placement, foreign body retrieval and thoracentesis. C-arm CT accounted for between 9.9% and 80.7% of the total procedural DAP.

CONCLUSION

Dose-reducing techniques can preserve image quality for intervention while reducing radiation exposure to the child. This technology has multiple applications within pediatric interventional radiology and can be considered as an adjunctive imaging tool in a variety of procedures, particularly when percutaneous access is challenging despite routine fluoroscopic or ultrasound guidance.

Extracranial Aneurysms in 2 Patients with Autosomal Recessive Polycystic Kidney Disease

Unlike autosomal dominant polycystic kidney disease (ADPKD), autosomal recessive polycystic kidney disease (ARPKD) is not generally known to be associated with vascular abnormalities. Only 4 cases of ARPKD patients with intracranial aneurysms have been reported previously. We present 2 ARPKD patients with extracranial vascular abnormalities: a young man with infrarenal aortic and iliac artery aneurysms complicated by dissection and a teenage girl with multiple splenic and gastric artery aneurysms and arterial vascular malformations. These cases raise the question of whether vascular integrity and development may be impaired in ARPKD, perhaps through molecular mechanisms overlapping with ADPKD. This possibility is supported by studies in mice that show ARPKD gene expression in the walls of large blood vessels.

Percutaneous Treatment of Lymphatic Malformations

Lymphatic malformations are slow-flow vascular anomalies composed of dilated lymphatic channels and cysts of varying sizes. Percutaneous treatments, particularly sclerotherapy, play an important role in the treatment of these lesions, often obviating the need for surgical intervention. Owing to the complex nature of these lesions, a multidisciplinary approach should be used to guide diagnosis and management. This submission focuses on the workup and treatment of pediatric lymphatic malformations at our institution, with a focus on sclerotherapy. Therapeutic outcomes and the management of postprocedural complications are also discussed.

IVC filter retrieval in adolescents: experience in a tertiary pediatric center

BACKGROUND

Inferior vena cava (IVC) filters are commonly implanted with the intent to prevent life-threatening pulmonary embolism in at-risk patients with contraindications to anticoagulation. Various studies have reported increases in the rate of venous thromboembolism within the pediatric population. The utility and safety of IVC filters in children has not yet been fully defined.

OBJECTIVE

To describe the technique and adjunctive maneuvers of IVC filter removal in children, demonstrate its technical success and identify complications.

MATERIALS AND METHODS

A retrospective 10-year review was performed of 20 children (13 male, 7 female), mean age: 15.1 years (range: 12-19 years), who underwent IVC filter retrieval. Eleven of 20 (55%) were placed in our institution. Electronic medical records were reviewed for filter characteristics, retrieval technique, technical success and complications.

RESULTS

The technical success rate was 100%. Placement indications included: deep venous thrombosis with a contraindication to anticoagulation (10/20, 50%), free-floating thrombus (4/20, 20%), post-trauma pulmonary embolism prophylaxis (3/20, 15%) and pre-thrombolysis pulmonary patient (1/20, 5%). The mean implantation period was 63 days (range: 20-270 days). Standard retrieval was performed in 17/20 patients (85%). Adjunctive techniques were performed in 3/20 patients (15%) and included the double-snare technique, balloon assistance and endobronchial forceps retrieval. Median procedure time was 60 min (range: 45-240 min). Pre-retrieval cavogram demonstrated filter tilt in 5/20 patients (25%) with a mean angle of 17° (range: 8-40). Pre-retrieval CT demonstrated strut wall penetration and tip embedment in one patient each. There were two procedure-related complications: IVC mural dissection noted on venography in one patient and snare catheter fracture requiring retrieval in one patient. There were no early or late complications.

CONCLUSION

In children, IVC filter retrieval can be performed safely but may be challenging, especially in cases of filter tilt or embedding. Adjunctive techniques may increase filter retrieval rates.