Anand S. Patel

Development and Validation of Endovascular Chemotherapy Filter Device for Removing High-Dose Doxorubicin: Preclinical Study

To develop a novel endovascular chemotherapy filter (CF) able to remove excess drug from the blood during intra-arterial chemotherapy delivery (IAC), thus preventing systemic toxicities and thereby enabling higher dose IAC. A flow circuit containing 2.5 mL of ion-exchange resin was constructed. Phosphate-buffered saline (PBS) containing 50 mg doxorubicin (Dox) was placed in the flow model with the hypothesis that doxorubicin would bind rapidly to resin. To simulate IAC, 50 mg of doxorubicin was infused over 10 min into the flow model containing resin. Similar testing was repeated with porcine serum. Doxorubicin concentrations were measured over 60 min and compared to controls (without resin). Single-pass experiments were also performed. Based on these experiments, an 18F CF was constructed with resin in its tip. In a pilot porcine study, the device was deployed under fluoroscopy. A control hepatic doxorubicin IAC model (no CF placed) was developed in another animal. A second CF device was created with a resin membrane and tested in the infrarenal inferior vena cava (IVC) of a swine. In the PBS model, resin bound 76% of doxorubicin in 10 min, and 92% in 30 min (P < 0.001). During IAC simulation, 64% of doxorubicin bound in 10 min and 96% in 60 min (P < 0.001). On average, 51% of doxorubicin concentration was reduced during each pass in single pass studies. In porcine serum, 52% of doxorubicin bound in 10 min, and 80% in 30 min (P < 0.05). CF device placement and administration of IAC were successful in three animals. No clot was present on the resin within the CF following the in vivo study. The infrarenal IVC swine study demonstrated promising results with up to 85% reduction in peak concentration by the CF device. An endovascular CF device was developed and shown feasible in vitro. An in vivo model was established with promising results supporting high-capacity rapid doxorubicin filtration from the blood that can be further evaluated in future studies.

Patient-directed Internet-based Medical Image Exchange:

RATIONALE AND OBJECTIVES Inefficient transfer of personal health records among providers negatively impacts quality of health care and increases cost. This multicenter study evaluates the implementation of the first Internet-based image-sharing system that gives patients ownership and control of their imaging exams, including assessment of patient satisfaction. MATERIALS AND METHODS Patients receiving any medical imaging exams in four academic centers were eligible to have images uploaded into an online, Internet-based personal health record. Satisfaction surveys were provided during recruitment with questions on ease of use, privacy and security, and timeliness of access to images. Responses were rated on a five-point scale and compared using logistic regression and McNemars test. RESULTS A total of 2562 patients enrolled from July 2012 to August 2013. The median number of imaging exams uploaded per patient was 5. Most commonly, exams were plain X-rays (34.7%), computed tomography (25.7%), and magnetic resonance imaging (16.1%). Of 502 (19.6%) patient surveys returned, 448 indicated the method of image sharing (Internet, compact discs [CDs], both, other). Nearly all patients (96.5%) responded favorably to having direct access to images, and 78% reported viewing their medical images independently. There was no difference between Internet and CD users in satisfaction with privacy and security and timeliness of access to medical images. A greater percentage of Internet users compared to CD users reported access without difficulty (88.3% vs. 77.5%, P < 0.0001). CONCLUSION A patient-directed, interoperable, Internet-based image-sharing system is feasible and surpasses the use of CDs with respect to accessibility of imaging exams while generating similar satisfaction with respect to privacy.

Atypical MRI features in soft-tissue arteriovenous malformation: a novel imaging appearance with radiologic-pathologic correlation.

BackgroundThe absence of a discrete mass, surrounding signal abnormality and solid enhancement are imaging features that have traditionally been used to differentiate soft-tissue arteriovenous malformations from vascular tumors on MRI. We have observed that these findings are not uncommon in arteriovenous malformations, which may lead to misdiagnosis or inappropriate treatment.ObjectiveTo estimate the frequency of atypical MRI features in soft-tissue arteriovenous malformations and assess their relationship to lesion size, location, tissue type involved and vascular architecture.Materials and methodsMedical records, MRI and histopathology were reviewed in consecutive patients with soft-tissue arteriovenous malformations in a multidisciplinary vascular anomalies clinic. Arteriovenous malformations were divided into those with and without atypical MRI findings (perilesional T2 signal abnormality, enhancement and/or a soft-tissue mass). Lesion location, size, tissue involved and vascular architecture were also compared between groups. Tissue stains were reviewed in available biopsy or resection specimens to assess relationships between MRI findings and histopathology.ResultsThirty patients with treatment-naïve arteriovenous malformations were included. Fifteen lesions demonstrated atypical MRI. There was no difference in age, gender, lesion size or involved body part between the groups. However, more than half of the atypical lesions demonstrated multicompartmental involvement, and tiny intralesional flow voids were more common in atypical arteriovenous malformations. Histopathology also differed in atypical cases, showing densely packed endothelial cells with connective tissue architectural distortion and edema.ConclusionArteriovenous malformations may exhibit features of a vascular tumor on MRI, particularly when multicompartmental and/or containing tiny internal vessels. These features are important to consider in suspected fast-flow vascular malformations and may have implications with respect to their treatment.

Magnetically-Assisted Remote Controlled Microcatheter Tip Deflection under Magnetic Resonance Imaging.

X-ray fluoroscopy-guided endovascular procedures have several significant limitations, including difficult catheter navigation and use of ionizing radiation, which can potentially be overcome using a magnetically steerable catheter under MR guidance. The main goal of this work is to develop a microcatheter whose tip can be remotely controlled using the magnetic field of the MR scanner. This protocol aims to describe the procedures for applying current to the microcoil-tipped microcatheter to produce consistent and controllable deflections. A microcoil was fabricated using laser lathe lithography onto a polyimide-tipped endovascular catheter. In vitro testing was performed in a waterbath and vessel phantom under the guidance of a 1.5-T MR system using steady-state free precession (SSFP) sequencing. Various amounts of current were applied to the coils of the microcatheter to produce measureable tip deflections and navigate in vascular phantoms. The development of this device provides a platform for future testing and opportunity to revolutionize the endovascular interventional MRI environment.

In Vitro Capture of Small Ferrous Particles with a Magnetic Filtration Device Designed for Intravascular Use with Intraarterial Chemotherapy: Proof-of-Concept Study.

PURPOSE To establish that a magnetic device designed for intravascular use can bind small iron particles in physiologic flow models. MATERIALS AND METHODS Uncoated iron oxide particles 50-100 nm and 1-5 µm in size were tested in a water flow chamber over a period of 10 minutes without a magnet (ie, control) and with large and small prototype magnets. These same particles and 1-µm carboxylic acid-coated iron oxide beads were likewise tested in a serum flow chamber model without a magnet (ie, control) and with the small prototype magnet. RESULTS Particles were successfully captured from solution. Particle concentrations in solution decreased in all experiments (P < .05 vs matched control runs). At 10 minutes, concentrations were 98% (50-100-nm particles in water with a large magnet), 97% (50-100-nm particles in water with a small magnet), 99% (1-5-µm particles in water with a large magnet), 99% (1-5-µm particles in water with a small magnet), 95% (50-100-nm particles in serum with a small magnet), 92% (1-5-µm particles in serum with a small magnet), and 75% (1-µm coated beads in serum with a small magnet) lower compared with matched control runs. CONCLUSIONS This study demonstrates the concept of magnetic capture of small iron oxide particles in physiologic flow models by using a small wire-mounted magnetic filter designed for intravascular use.

O-016 Development and Validation of an Endovascular Chemotherapy Filter Device for Removing High-Dose Doxorubicin from the Blood: In Vivo Porcine Study

Purpose A novel disposable endovascular chemotherapy filter (CF) device was developed to remove excess doxorubicin (Dox) from the blood during intra-arterial chemotherapy delivery to prevent systemic toxicities. Previous proof-of-concept established the capacity of the filter to bind Dox in swine serum in vitro. In this study, CF navigation, deployment and in vivo Dox binding was evaluated in the porcine inferior vena cava (IVC). Materials and methods An 18 Fr CF device was constructed with an ion-exchange membrane attached to an expandable 28 mm diameter Nitinol frame. Under X-ray fluoroscopy and contrast venography, the CF was percutaneously introduced via the internal jugular vein and deployed in the porcine infrarenal IVC. 50 mg of Dox (2 mg/ml) was injected over 10 min in the IVC below the CF device. Venous catheters with tips proximal and distal to the CF device in the infrarenal IVC obtained pressures and blood samples for Dox concentrations over 90 min across the CF device membrane. Results The CF device was successfully introduced and deployed in the infrarenal IVC in vivo. Visualization under X-ray fluoroscopy verified the proper placement and mechanical expansion of the Nitinol framework. In a 90 min study, the device was biocompatible, not leading to hemodynamic disturbances: pressure measurements taken throughout the experiment yielded a max gradient of 17 mmHg across the CF membrane. Venography demonstrated non-flow-limiting thrombus associated with the CF device after 90 min of deployment (swine were not heparinized). Significant Dox binding was noted with an 85%, 74%, and 83% decrease in relative pre- versus post-filter Dox concentrations at times 3, 10, and 30 min, respectively after Dox injection. Conclusion: We developed a biocompatible CF device that can be safely introduced, deployed, and removed from the IVC in vivo. The CF device demonstrated significant Dox binding, and could serve as a platform technology in drug therapy to allow for higher regional doses of drug while limiting systemic toxicity. In future in vivo experiments, animals or the CF device itself may be heparinized in order to prevent thrombosis. When fully developed, indications for this device could include head and neck cancer, with the device deployed in the superior vena cava or internal jugular veins during selective IA chemotherapy. Disclosures A. Patel: 1; C; NIH-NCI. 4; C; ChemoFilter. A. Chin: 1; C; NIH-NCI. 4; C; ChemoFilter. J. Yang: None. B. Thorne: None. M. Saeed: None. M. Wilson: 1; C; NIH-NIBIB, NIH-NCI. 4; C; ChemoFilter. S. Hetts: 1; C; NIH-NIBIB, NIH-NCI, Siemens, Covidien. 2; C; Stryker, Penumbra, Silk Road Medical, Medina Medical. 4; C; ChemoFilter, Medina Medical, DriftCoast.

A simple noniterative principal component technique for rapid noise reduction in parallel MR images.

The utilization of parallel imaging permits increased MR acquisition speed and efficiency; however, parallel MRI usually leads to a deterioration in the signal‐to‐noise ratio when compared with otherwise equivalent unaccelerated acquisitions. At high accelerations, the parallel image reconstruction matrix tends to become dominated by one principal component. This has been utilized to enable substantial reductions in g‐factor‐related noise. A previously published technique achieved noise reductions via a computationally intensive search for multiples of the dominant singular vector which, when subtracted from the image, minimized joint entropy between the accelerated image and a reference image. We describe a simple algorithm that can accomplish similar results without a time‐consuming search. Significant reductions in g‐factor‐related noise were achieved using this new algorithm with in vivo acquisitions at 1.5 T with an eight‐element array. Copyright