Biomedical subjects

Bensheng Qiu

Publications and source records attributed to Bensheng Qiu.

3 recordsLinked to original sources

PubMed2003

In vivo US monitoring of catheter-based vascular delivery of gene microspheres in pigs: feasibility.

In this study, the authors tested the feasibility of using ultrasonography (US) to monitor catheter-based vascular gene microsphere delivery. Polymeric biodegradable microspheres (mean diameter, 5 microm) were prepared by using a double-emulsion technique to encapsulate DNA-plasmid-encoding green fluorescent protein (GFP) genes. With use of gene-delivery catheters, GFP microspheres were locally delivered into the left femoral arterial walls of six pigs; the contralateral arteries were not infused with microspheres and thus served as negative control vessels. The delivery procedures were monitored with high-frequency (8-15-MHz) transducer US. The effectiveness of monitoring with US was compared with the effectiveness of monitoring with immunohistochemical anti-GFP staining. A highly echogenic "star burst" sign around the entire vessel wall was seen at US and correlated with immunohistochemical findings that showed the destination of the gene microspheres. Study results demonstrate the potential of US for monitoring catheter-based vascular gene microsphere delivery in vivo.

Animals↗

PubMed2002

Development of an intravascular heating source using an MR imaging guidewire.

PURPOSE: To develop a novel endovascular heating source using a magnetic resonance (MR) imaging guidewire (MRIG) to deliver controlled microwave energy into the target vessel for thermal enhancement of vascular gene transfection. MATERIALS AND METHODS: A 0.032-inch MRIG was connected to a 2.45-GHz microwave generator. We 1) calculated the microwave power loss along the MRIG, 2) simulated the power distribution around the MRIG, 3) measured the temperature increase vs. input power with the MRIG, and 4) evaluated the thermal effect on the balloon-compressed/microwave-heated aorta of six living rabbits. In addition, during balloon inflation, we also simultaneously generated high-resolution MR images of the aortic wall. RESULTS: The power loss was calculated to be 3.9 dB along the MRIG. The simulation-predicted power distribution pattern was cylindrically symmetric, analogous to the geometry of vessels. Under balloon compression, the vessel wall could be locally heated at 41 degrees C with no thermal damage apparent on histology. CONCLUSION: This study demonstrates the possibility of using the MRIG as a multifunctional device, not only as a receiver antenna to generate intravascular high-resolution MR images of atherosclerotic plaques and as a conventional guidewire to guide endovascular interventions during MR imaging, but also as a potential intravascular heating source to produce local heat for thermal enhancement of vascular gene transfection.

Animals↗

PubMed2002

Fast maximum intensity projection algorithm using shear warp factorization and reduced resampling.

Maximal intensity projection (MIP) is routinely used to view MRA and other volumetric angiographic data. The straightforward implementation of MIP is ray casting that traces a volumetric data set in a computationally expensive manner. This article reports a fast MIP algorithm using shear warp factorization and reduced resampling that drastically reduced the redundancy in the computations for projection, thereby speeding up MIP by more than 10 times.

Algorithms↗