Adrenal Biopsy under Wide-Bore MR Imaging Guidance.

Twenty-four magnetic resonance (MR) imaging-guided percutaneous adrenal biopsies performed between April 2009 and October 2016 were reviewed retrospectively. Epidemiologic, procedural, and histopathologic data were retrospectively collected. Mean size of tumors was 4.3 cm (range, 1.5-16.0 cm). Mean procedure time was 49 min (range, 24-95 min). Mean needle angulation was 27.7° (range, 0°-60°). Mean depth was 9.6 cm (range, 5.8-13.7 cm). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of MR imaging-guided biopsy were 95.5%, 100%, 100%, 66.7%, and 95.8%, respectively. There were no immediate or delayed complications. MR imaging guidance seems safe and accurate to target adrenal-gland masses.

Percutaneous Image-Guided Cryoablation for the Treatment of Phantom Limb Pain in Amputees: A Pilot Study.

PURPOSE: To prospectively evaluate percutaneous image-guided nerve cryoablation for treatment of refractory phantom limb pain (PLP) in a pilot cohort for purposes of deriving parameters to design a larger, randomized, parallel-armed, controlled trial. MATERIALS AND METHODS: From January 2015 to January 2016, 21 patients with refractory PLP underwent image-guided percutaneous cryoneurolysis procedures. Visual analog scale scores were documented at baseline and 7, 45, and 180 days after the procedure. Responses to a modified Roland Morris Disability Questionnaire were documented at baseline and 7 and 45 days after the procedure. RESULTS: Technical success rate of the procedures was 100%. There were 6 (29%) minor procedure-related complications. Disability scores decreased from a baseline mean of 11.3 to 3.3 at 45-day follow-up (95% confidence interval 5.8, 10.3; P < .0001). Pain intensity scores decreased from a baseline mean of 6.2 to 2.0 at long-term follow-up (95% confidence interval 2.8, 5.6; P < .0001). CONCLUSIONS: Image-guided percutaneous nerve cryoablation is feasible and safe and may represent a new efficacious therapeutic option for patients with phantom pains related to limb loss.

The effects of expanding outpatient and inpatient evaluation and management services in a pediatric interventional radiology practice.

BACKGROUND: Despite a continuing emphasis on evaluation and management clinical services in adult interventional radiology (IR) practice, the peer-reviewed literature addressing these services - and their potential economic benefits - is lacking in pediatric IR practice. OBJECTIVE: To measure the effects of expanding evaluation and management (E&M) services through the establishment of a dedicated pediatric interventional radiology outpatient clinic and inpatient E&M reporting system. MATERIALS AND METHODS: We collected and analyzed E&M current procedural terminology (CPT) codes from all patients seen in a pediatric interventional radiology outpatient clinic between November 2014 and August 2015. We also calculated the number of new patients seen in the clinic who had a subsequent procedure (procedural conversion rate). For comparison, we used historical data comprising pediatric patients seen in a general interventional radiology (IR) clinic for the 2 years immediately prior. An inpatient E&M reporting system was implemented and all inpatient E&M (and subsequent procedural) services between July 2015 and September 2015 were collected and analyzed. We estimated revenue for both outpatient and inpatient services using the Medicare Physician Fee Schedule global non-facility price as a surrogate. RESULTS: Following inception of a pediatric IR clinic, the number of new outpatients (5.5/month; +112%), procedural conversion rate (74.5%; +19%), estimated E&M revenue (+158%), and estimated procedural revenue from new outpatients (+228%) all increased. Following implementation of an inpatient clinic reporting system, there were 8.3 consults and 7.3 subsequent hospital encounters per month, with a procedural conversion rate of 88%. CONCLUSION: Growth was observed in all meaningful metrics following expansion of outpatient and inpatient pediatric IR E&M services.

Anatomical risk evaluation of iatrogenic injury to the infrapatellar branch of the saphenous nerve during medial meniscus arthroscopic surgery.

PURPOSE: To determine the relationship of the medial meniscus with the infrapatellar branches of the saphenous nerve, the primary goal is to define and characterize different risk areas for these nerves during medial meniscus surgery. METHODS: After dissecting 20 embalmed cadaver knees, we defined 7 readily identifiable anatomical landmarks. For each knee, we recorded 2 morphological criteria and 16 measurements. RESULTS: The most common anatomical course is a main trunk that is 8 mm anterior to the tuberculum adductorium and 60 mm posterior to the midpoint of the medial patellar margin. It has two main infrapatellar branches. The nerve division is 23 mm above the joint line. The path is oblique with an angle of 55.5°. The anterior meniscal landmark is 24 mm from the upper branch and 42.5 mm from the lower branch. The posterior meniscal landmark is 55 mm from the upper branch and 38 mm from the lower branch. CONCLUSIONS: We defined a common anatomical course for the saphenous nerve and its infrapatellar branches. Then, three different areas were defined at risk for iatrogenic nerve injuries during medial meniscus.

Immediate post-doxorubicin drug-eluting beads chemoembolization Mr Apparent diffusion coefficient quantification predicts response in unresectable hepatocellular carcinoma: A pilot study.

PURPOSE: To investigate magnetic resonance imaging (MRI) diffusion-weighted imaging (DWI) of hepatocellular carcinoma (HCC) immediately post-doxorubicin drug-eluting beads transcatheter arterial chemoembolization (DEB-TACE) therapy as an early imaging biomarker of therapy response. MATERIALS AND METHODS: In a single-center prospective correlative study, 12 consecutive patients, median age 64 years, underwent DEB-TACE and dynamic contrast-enhanced (DCE) and DWI (b = 50,400,800 s/mm(2)) MRI at baseline with respect to first DEB-TACE, within 3 hours, and at 1 and 3 months posttherapy. DCE imaging response was evaluated according to target mRECIST and EASL. Relative change (RC) in apparent diffusion coefficient (ADC) of treated lesions was measured on follow-ups. Correlation between ADC RC in tumors and anatomical response were evaluated with paired t-test and receiver operator characteristic (ROC) curve. Survival from first DEB-TACE was estimated using Kaplan-Meier and log-rank analysis. RESULTS: Compared to baseline, mean ADC increased significantly for responders within 3 hours post-DEB-TACE (0.73 ± 0.20 mm(2) /s vs. 0.99 ± 0.28 mm(2) /s × 10(-3) (P = 0.001)). There was no significant change in ADC within 3 hours for nonresponders. ADC RC threshold of 20% immediately post-DEB-TACE showed 100% sensitivity and specificity in predicting anatomical response at 1 and 3 months with patients with ≥20% ADC increase demonstrated significantly prolonged mean overall survival compared to others (25.4 vs. 13.3 months (P = 0.017)). CONCLUSION: ADC relative change of ≥20% immediately post-DEB-TACE is an accurate predictor of objective and quantitative treatment response and prolonged survival in unresectable HCC.

Celiac Plexus Cryoneurolysis.

Intractable, chronic abdominal pain from upper abdominal malignant and benign diseases is a significant challenge for healthcare providers and burden on the healthcare system. While opioid analgesics are commonly used to provide pain relief, the adverse effects of chronic opioid use cannot be overlooked. Celiac plexus neurolysis via chemical or thermal means represents an alternative minimally invasive approach to provide palliative pain relief and increase patients' quality of life. Through the use of computed tomography guidance, celiac plexus neurolysis can be performed by accurately targeting the celiac plexus, while minimizing risks to adjacent structures. Historically, celiac plexus neurolysis was performed via instillation of ethanol or phenol; however, within the past decade cryoablation has gained increasing use with potentially fewer side effects.

Interventional Cryoneurolysis: An Illustrative Approach.

The application of advanced imaging guidance and the interventional radiology skill set has expanded the breadth of nerve and nerve plexus targets in the body for potential cryoneurolysis. Advancement of the basic science supporting cryoneurolysis has further solidified proceduralists' confidence and ability to select and manage patients clinically. As these procedures continue to evolve, a structured approach to the wide variety of indications is necessary.

Percutaneous Biopsy of Retrobulbar Masses: Anatomical Considerations and MRI Guidance.

PURPOSE: Obtaining adequate tissue from retrobulbar masses remains a challenge. To this end, a new method of retrobulbar mass biopsy using MRI guidance is presented. MATERIALS AND METHODS: Two patients (7- and 71-year-old male) with indeterminate retrobulbar masses underwent bioptic and cytological samplings using MR-compatible 18G and 20-22G needles, and multi-planar MR fluoroscopy. An inferior approach was taken to avoid injury to the optic nerve and ophthalmic arteries. RESULTS: The two biopsies were completed without complication. The core biopsy resulted in a final diagnosis, whereas the cytological sampling was non-diagnostic. CONCLUSION: Percutaneous MR-guided retrobulbar mass biopsy proved to be feasible and safe in the two cases described in this report.

Standardized Added Metabolic Activity Predicts Survival After Intra-arterial Resin-Based 90Y Radioembolization Therapy in Unresectable Chemorefractory Metastatic Colorectal Cancer to the Liver.

PURPOSE: Standardized added metabolic (SAM) activity is a functional objective measurement of the total tumoral metabolic activity that avoids partial volume effect and thresholding, which limit conventional PET parameters. The purpose of this study is to investigate the role of SAM in predicting survival in unresectable, chemorefractory colorectal hepatic metastatic disease treated with resin-based Y radioembolization. MATERIALS AND METHODS: This is a prospective correlative study of patients with unresectable, chemorefractory colorectal liver metastasis who underwent F-FDG PET/CT and CT/MRI before and after Y. Target RECIST, PERCIST, change in total glycolytic activity (ΔTGA), and ΔSAM treatment response were assessed. Percentage changes in diameter, SUVpeak, TGA, and SAM were calculated pre- and post-Y therapy and objective response was defined as >30% change (responders). Survival analysis by Kaplan-Meier, log-rank, and Cox proportional hazard models were performed and significance was set at <0.05. RESULTS: Sixteen patients (mean age of 61.6) were enrolled and performed a total of 20 Y therapies. After Y, target ΔSAM showed an objective response rate of 40% vs. 35%, 30%, and 22.2% based on target ΔTGA, PERCIST, and RECIST criteria, respectively. Median overall survival (OS) of the cohort after Y was 9.2 months (CI 95% 2.2-16.2). Patients demonstrating objective response based on ΔSAM had a median OS of 22.7 months (CI 95% 12.4-33.0) vs. 6.7 (CI 95% 4.2-9.2) in non-responders (P = 0.007). On multivariate analysis, hazard ratios for the objective response group based on target ΔSAM were 0.01 (P = 0.03) vs. 0.05 (P = 0.08), 0.20 (P = 0.29), and 0.91 (P = 0.98) based on target ΔTGA, PERCIST, and RECIST criteria, respectively. CONCLUSIONS: In unresectable colorectal liver metastatic disease refractory to standard chemotherapy, ΔSAM predicted OS for assessment of response following Y radioembolization therapy, whereas RECIST, PERCIST, and ΔTGA did not.

Image-Guided Spinal Ablation: A Review.

The image-guided thermal ablation procedures can be used to treat a variety of benign and malignant spinal tumours. Small size osteoid osteoma can be treated with laser or radiofrequency. Larger tumours (osteoblastoma, aneurysmal bone cyst and metastasis) can be addressed with radiofrequency or cryoablation. Results on the literature of spinal microwave ablation are scarce, and thus it should be used with caution. A distinct advantage of cryoablation is the ability to monitor the ice-ball by intermittent CT or MRI. The different thermal insulation, temperature and electrophysiological monitoring techniques should be applied. Cautious pre-procedural planning and intermittent intra-procedural monitoring of the ablation zone can help reduce neural complications. Tumour histology, patient clinical-functional status and life-expectancy should define the most efficient and least disabling treatment option.

Safety and efficacy of a circumferential clip-based vascular closure device in cirrhotic and coagulopathic patients with hepatocellular carcinoma after doxorubicin drug-eluting beads transarterial chemoembolization.

PURPOSE: This study was designed to investigate the safety and efficacy of the circumferential clip-based (StarClose) vascular closure device (VCD) in coagulopathic and cirrhotic patients with hepatocellular carcinoma (HCC) after doxorubicin drug-eluting beads transarterial chemoembolization (DEB TACE). METHODS: Consecutive cirrhotic patients with HCC, who underwent DEB TACE from November 2009 to February 2012, were included in the study. Based on platelet count (PC) and international normalized ratio (INR), these patients were further divided into group A (PC ≥ 150 k/dl), B (PC = 50-149 k/dl), C (PC < 50 k/dl), D (INR ≤ 1.2), E (INR = 1.21-1.5), and F (INR > 1.5). StarClose VCD was attempted in each case. Technical success was defined as complete hemostasis achieved within 3 min after the closure. Periprocedural complications were studied. RESULTS: A total of 350 DEB TACEs were performed in 195 patients (mean age 61.6 years, SD 9.1). StarClose VCD was attempted in all cases. StarClose device was not deployed in 2.2 % (8/350) of cases due to improper femoral punctures and severe atherosclerotic disease. Technical success rate was 97.1 % (332/342). All groups (A-F) were similar in age, sex, body mass index, and technical success rate (P > 0.05). Minor complications occurred after 1.8 % (6/342) of cases. VCD was repeatedly used in 92 patients with 96.2 % (230/239) of technical success rate. There was no major complication related to VCD. There was no access site infection, leg ischemia, and pseudoaneurysm or symptomatic groin hematoma. CONCLUSIONS: Circumferential clip based (StarClose) arterial closure device achieved effective and rapid hemostasis after DEB TACE with minimal complications in cirrhotic patients with HCC and coagulopathy. StarClose deployment and reaccess in patients with PC < 50 k/dl and INR > 1.2 are safe and effective.

Development of functional biomaterials with micro- and nanoscale technologies for tissue engineering and drug delivery applications.

Micro- and nanotechnologies have emerged as potentially effective fabrication tools for addressing the challenges faced in tissue engineering and drug delivery. The ability to control and manipulate polymeric biomaterials at the micron and nanometre scale with these fabrication techniques has allowed for the creation of controlled cellular environments, engineering of functional tissues and development of better drug delivery systems. In tissue engineering, micro- and nanotechnologies have enabled the recapitulation of the micro- and nanoscale detail of the cell's environment through controlling the surface chemistry and topography of materials, generating 3D cellular scaffolds and regulating cell-cell interactions. Furthermore, these technologies have led to advances in high-throughput screening (HTS), enabling rapid and efficient discovery of a library of materials and screening of drugs that induce cell-specific responses. In drug delivery, controlling the size and geometry of drug carriers with micro- and nanotechnologies have allowed for the modulation of parametres such as bioavailability, pharmacodynamics and cell-specific targeting. In this review, we introduce recent developments in micro- and nanoscale engineering of polymeric biomaterials, with an emphasis on lithographic techniques, and present an overview of their applications in tissue engineering, HTS and drug delivery.

Biocompatibility of engineered nanoparticles for drug delivery.

The rapid advancement of nanotechnology has raised the possibility of using engineered nanoparticles that interact within biological environments for treatment of diseases. Nanoparticles interacting with cells and the extracellular environment can trigger a sequence of biological effects. These effects largely depend on the dynamic physicochemical characteristics of nanoparticles, which determine the biocompatibility and efficacy of the intended outcomes. Understanding the mechanisms behind these different outcomes will allow prediction of the relationship between nanostructures and their interactions with the biological milieu. At present, almost no standard biocompatibility evaluation criteria have been established, in particular for nanoparticles used in drug delivery systems. Therefore, an appropriate safety guideline of nanoparticles on human health with assessable endpoints is needed. In this review, we discuss the data existing in the literature regarding biocompatibility of nanoparticles for drug delivery applications. We also review the various types of nanoparticles used in drug delivery systems while addressing new challenges and research directions. Presenting the aforementioned information will aid in getting one step closer to formulating compatibility criteria for biological systems under exposure to different nanoparticles.

Material strategies for creating artificial cell-instructive niches.

There has been a tremendous growth in the use of biomaterials serving as cellular scaffolds for tissue engineering applications. Recently, advanced material strategies have been developed to incorporate structural, mechanical, and biochemical signals that can interact with the cell and the in vivo environment in a biologically specific manner. In this article, strategies such as the use of composite materials and material processing methods to better mimic the extracellular matrix, integration of mechanical and topographical properties of materials in scaffold design, and incorporation of biochemical cues such as cytokines in tethered, soluble, or time-released forms are presented. Finally, replication of the dynamic forces and biochemical gradients of the in vivo cellular environment through the use of microfluidics is highlighted.

Engineering microscale topographies to control the cell-substrate interface.

Cells in their in vivo microenvironment constantly encounter and respond to a multitude of signals. While the role of biochemical signals has long been appreciated, the importance of biophysical signals has only recently been investigated. Biophysical cues are presented in different forms including topography and mechanical stiffness imparted by the extracellular matrix and adjoining cells. Microfabrication technologies have allowed for the generation of biomaterials with microscale topographies to study the effect of biophysical cues on cellular function at the cell-substrate interface. Topographies of different geometries and with varying microscale dimensions have been used to better understand cell adhesion, migration, and differentiation at the cellular and sub-cellular scales. Furthermore, quantification of cell-generated forces has been illustrated with micropillar topographies to shed light on the process of mechanotransduction. In this review, we highlight recent advances made in these areas and how they have been utilized for neural, cardiac, and musculoskeletal tissue engineering application.

Engineering approaches toward deconstructing and controlling the stem cell environment.

Stem cell-based therapeutics have become a vital component in tissue engineering and regenerative medicine. The microenvironment within which stem cells reside, i.e., the niche, plays a crucial role in regulating stem cell self-renewal and differentiation. However, current biological techniques lack the means to recapitulate the complexity of this microenvironment. Nano- and microengineered materials offer innovative methods to (1) deconstruct the stem cell niche to understand the effects of individual elements; (2) construct complex tissue-like structures resembling the niche to better predict and control cellular processes; and (3) transplant stem cells or activate endogenous stem cell populations for regeneration of aged or diseased tissues. In this article, we highlight some of the latest advances in this field and discuss future applications and directions of the use of nano- and microtechnologies for stem cell engineering.

Building vascular networks.

Only a few engineered tissues-skin, cartilage, bladder-have achieved clinical success, and biomaterials designed to replace more complex organs are still far from commercial availability. This gap exists in part because biomaterials lack a vascular network to transfer the oxygen and nutrients necessary for survival and integration after transplantation. Thus, generation of a functional vasculature is essential to the clinical success of engineered tissue constructs and remains a key challenge for regenerative medicine. In this Perspective, we discuss recent advances in vascularization of biomaterials through the use of biochemical modification, exogenous cells, or microengineering technology.

Directed endothelial cell morphogenesis in micropatterned gelatin methacrylate hydrogels.

Engineering of organized vasculature is a crucial step in the development of functional and clinically relevant tissue constructs. A number of previous techniques have been proposed to spatially regulate the distribution of angiogenic biomolecules and vascular cells within biomaterial matrices to promote vascularization. Most of these approaches have been limited to two-dimensional (2D) micropatterned features or have resulted in formation of random vasculature within three-dimensional (3D) microenvironments. In this study, we investigate 3D endothelial cord formation within micropatterned gelatin methacrylate (GelMA) hydrogels with varying geometrical features (50-150 µm height). We demonstrated the significant dependence of endothelial cells proliferation, alignment and cord formation on geometrical dimensions of the patterned features. The cells were able to align and organize within the micropatterned constructs and assemble to form cord structures with organized actin fibers and circular/elliptical cross-sections. The inner layer of the cord structure was filled with gel showing that the micropatterned hydrogel constructs guided the assembly of endothelial cells into cord structures. Notably, the endothelial cords were retained within the hydrogel microconstructs for all geometries after two weeks of culture; however, only the 100 µm-high constructs provided the optimal microenvironment for the formation of circular and stable cord structures. Our findings suggest that endothelial cord formation is a preceding step to tubulogenesis and the proposed system can be used to develop organized vasculature for engineered tissue constructs.