Irreversible Electroporation of the Hepatobiliary System: Current Utilization and Future Avenues

Liver cancer remains a leading cause of cancer-related deaths worldwide despite numerous advances in treatment. While surgical resection remains the gold standard for curative treatment, it is only possible for a minority of patients. Thermal ablation is an effective option for the treatment of smaller tumors; however, its use is limited to tumors that are not located in proximity to sensitive structures due to the heat sink effect and the potential of thermal damage. Irreversible electroporation (IRE) is a non-thermal ablative modality that can deliver targeted treatment and the effective destruction of tumors that are in close proximity to or even surrounding vascular or biliary ducts with minimal damage to these structures. IRE produces short pulses of high-frequency energy which opens pores in the lipid bilayer of cells leading to apoptosis and cell death. IRE has been utilized clinically for over a decade in the treatment of liver cancers with multiple studies documenting an acceptable safety profile and high efficacy rates.

The multidisciplinary management of cholangiocarcinoma

Cholangiocarcinoma is a lethal malignancy of the biliary epithelium that can arise anywhere along the biliary tract. Surgical resection confers the greatest likelihood of long-term survivability. However, its insidious onset, difficult diagnostics, and resultant advanced presentation render the majority of patients unresectable, highlighting the importance of early detection with novel biomarkers. Developing liver-directed therapies and emerging targeted therapeutics may offer improved survivability for patients with unresectable or advanced disease. In this article, the authors review the current multidisciplinary standards of care in resectable and unresectable cholangiocarcinoma, with an emphasis on novel biomarkers for early detection and nonsurgical locoregional therapy options.

Upper Extremity Deep Venous Thrombosis: Etiologies, Diagnosis, and Updates in Therapeutic Strategies

Upper extremity deep vein thrombosis (UEDVT) is responsible for 4 to 10% of all deep vein thrombosis (DVT). Untreated UEDVT can lead to significant disability secondary to the postthrombotic syndrome. To date, there are no randomized trials specifically comparing different therapeutic strategies. Ultimately, optimal management of UEDVT depends on the underlying etiology, patient symptoms, and degree of thrombosis, with supporting evidence primarily extrapolated from lower extremity DVT data. This article will review the classification, presentation, and diagnosis of both primary and secondary UEDVT. In addition, it will discuss updates in clinical guidelines, anticoagulation, endovascular and surgical treatment strategies.

Therapy Resistant Gastroenteropancreatic Neuroendocrine Tumors

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a heterogenous group of malignancies originating from neuroendocrine cells of the gastrointestinal tract, the incidence of which has been increasing for several decades. While there has been significant progress in the development of therapeutic options for patients with advanced or metastatic disease, these remain limited both in quantity and durability of benefit. This review examines the latest research elucidating the mechanisms of both up-front resistance and the eventual development of resistance to the primary systemic therapeutic options including somatostatin analogues, peptide receptor radionuclide therapy with lutetium Lu 177 dotatate, everolimus, sunitinib, and temozolomide-based chemotherapy. Further, potential strategies for overcoming these mechanisms of resistance are reviewed in addition to a comprehensive review of ongoing and planned clinical trials addressing this important challenge.

Irreversible electroporation for colorectal cancer liver metastasis: a review

Irreversible electroporation (IRE) ablation is gaining popularity over the last decade as a nonthermal alternative to thermal ablation technologies such as radiofrequency ablation (RFA) and Microwave ablation (MWA). This review serves as a practical guide for applying IRE to colorectal cancer liver metastases (CRLM) for interventional radiologists, oncologists, surgeons, and anesthesiologists. It covers patient selection, procedural technique, anesthesia, imaging, and outcomes.

Genicular Artery Embolization for Primary Knee Osteoarthritis

Genicular artery embolization (GAE) is a novel treatment for knee osteoarthritis (OA) with increasing interest and utilization worldwide. The genicular arteries are selectively embolized using microspheres with subsequent cessation of abnormal synovial hyperemia, a process believed to arrest the inflammatory changes and pain associated with OA. Current data indicate that GAE offers sustained, 6-month improvement in Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) and visual analog scale scores in 80 to 85% of patients with mild to moderate OA. As GAE gains traction, future studies are needed to establish its safety and efficacy relative to placebo and other standard-of-care therapies while also characterizing populations for which it is most effective.

Percutaneous Therapies for Hepatocellular Carcinoma: Evolution of Liver Directed Therapies

Percutaneous ablation is a mainstay of treatment for early stage, unresectable hepatocellular carcinoma (HCC). Recent advances in technology have created multiple ablative modalities for treatment of this common malignancy. The purpose of this review is to familiarize readers with the technical and clinical aspects of both existing and emerging percutaneous treatment options for HCC.

"How We Do It" - A Practical Approach to Percutaneous Adrenal Ablation Techniques

Incidental adrenal masses are common and are found in 4% of the CT scans.¹ While clinical history, laboratory results, and imaging characteristics are typically sufficient for diagnosis of an adrenal lesion, a biopsy is sometimes warranted. In some cases, adrenal mass ablation is subsequently indicated. This article serves as a brief but comprehensive review of preprocedural work-up and planning before an adrenal mass ablation, as well as a discussion on ablation techniques, associated challenges and solutions, and management of expected and unexpected outcomes.

Collateral Uterine Arterial Supply in the Setting of Various Uterine Pathologies

In most patients, bilateral uterine arteries supply the uterus exclusively. However, collateral arterial supply to the uterus has been described, predominantly in the context of uterine artery embolization (UAE) for fibroid treatment. This may lead to incomplete embolization, which can impact clinical outcomes. Therefore, identification of potential collateral supply to the uterus is essential for achieving optimal clinical results. The authors report three cases of collateral uterine arterial supply from the ovarian and round ligament arteries in the setting of uterine arteriovenous fistula (uAVF), postpartum hemorrhage (PPH), and symptomatic fibroids. Aortography from the level of the renal arteries was performed for initial evaluation of uterine arterial supply in all patients and identified hypertrophied, tortuous ovarian artery collaterals. Selective angiography of the external iliac artery was required to identify round ligament collateral uterine supply. Three-dimensional cone beam computed tomography (CT) was also used to visualize vascular distribution of bilateral uterine arteries and an ovarian collateral feeding a uAVF. In regard to outcomes, identification of collateral uterine arterial supply allowed for single-session complete embolization in fibroid patients with collateralized round ligament or ovarian arteries and in the PPH patient in disseminated intravascular coagulation with predominantly ovarian artery supply to the uterus. Identification of collateral uterine arterial supply facilitated technical success in all patients. In the setting of various uterine pathologies, identification of collateral uterine arterial supply is essential to optimize clinical success of UAE.

Accuracy and efficacy of percutaneous biopsy and ablation using robotic assistance under computed tomography guidance: a phantom study

OBJECTIVE

To compare the accuracy of a robotic interventional radiologist (IR) assistance platform with a standard freehand technique for computed-tomography (CT)-guided biopsy and simulated radiofrequency ablation (RFA).

METHODS

The accuracy of freehand single-pass needle insertions into abdominal phantoms was compared with insertions facilitated with the use of a robotic assistance platform (n = 20 each). Post-procedural CTs were analysed for needle placement error. Percutaneous RFA was simulated by sequentially placing five 17-gauge needle introducers into 5-cm diameter masses (n = 5) embedded within an abdominal phantom. Simulated ablations were planned based on pre-procedural CT, before multi-probe placement was executed freehand. Multi-probe placement was then performed on the same 5-cm mass using the ablation planning software and robotic assistance. Post-procedural CTs were analysed to determine the percentage of untreated residual target.

RESULTS

Mean needle tip-to-target errors were reduced with use of the IR assistance platform (both P < 0.0001). Reduced percentage residual tumour was observed with treatment planning (P = 0.02).

CONCLUSION

Improved needle accuracy and optimised probe geometry are observed during simulated CT-guided biopsy and percutaneous ablation with use of a robotic IR assistance platform. This technology may be useful for clinical CT-guided biopsy and RFA, when accuracy may have an impact on outcome.

KEY POINTS

• A recently developed robotic intervention radiology assistance platform facilitates CT-guided interventions. • Improved accuracy of complex needle insertions is achievable. • IR assistance platform use can improve target ablation coverage.

PET-guided biopsy with needle navigation facilitates diagnosis of angiosarcoma in neurofibromatosis type 1

Malignant degeneration frequently arises from preexisting plexiform neurofibroma in patients with neurofibromatosis type 1 (NF1). Image guided biopsy for diagnostic purposes, such as with CT guidance, can be technically challenging in these patients, as CT cannot distinguish malignant from benign areas within the same tumor. Navigation with multi-modality (PET, CT, and ultrasound) image fusion facilitated the successful biopsy and diagnosis of angiosarcoma arising from a pelvic neurofibroma in a patient with NF1. Successful targeting assisted treatment selection in this case. This novel navigation technique may facilitate the otherwise difficult diagnosis of malignancy in patients with NF1.