Biomedical subjects

J Neuerburg

Publications and source records attributed to J Neuerburg.

60 records · Page 4Linked to original sources

PubMedDate not supplied

New retrievable percutaneous vena cava filter: experimental in vitro and in vivo evaluation.

A new retrievable percutaneous vena cava filter was tested in vitro and in vivo in 15 foxhounds. In vitro, the new vena cava filter was compared with the standard Kimray-Greenfield filter and the Günther basket filter. The new filter is a stainless steel half-basket filter and is suitable for percutaneous antegrade or retrograde insertion through a 8.5 Fr introducer sheath. In vitro testing showed the filter causing no significant flow alterations and being highly effective in capturing medium- and large-sized thrombi; furthermore, fatigue testing revealed no breakage of the new filter, whereas the Günther basket filter showed breakage of the struts. In vivo studies showed no occlusion, major perforation, or filter migration during follow-up of 2 weeks to 6 months. Tilting of the filter postimplantation occurred in two out of 28 filters. Ten of 11 filters were successfully retrieved by the transjugular approach 2 weeks after implantation. The device seems to be suitable for temporary or permanent protection against pulmonary embolism.

Animals↗

PubMedDate not supplied

Percutaneous biopsy of pancreatic lesions.

Percutaneous biopsy provides an effective means of tissue diagnosis in pancreatic lesions. Accuracy rates are ranging between 72 and 100%, with a sensitivity for carcinomas between 69 and 90% and a constantly high specificity of 100% in most series of the literature. The rate of major complications is low, with an incidence of about 0.05%.

Biopsy, Needle↗

PubMedDate not supplied

In vitro evaluation of a rheolytic thrombectomy system for clot removal from five different temporary vena cava filters.

PURPOSE: To evaluate the feasibility of thrombus removal from temporary vena cava filters using a rheolytic thrombectomy device and to assess the embolization rate of this procedure. METHODS: Five temporary vena cava filters together with porcine thrombi were placed in a vena cava flow model (semitranslucent silicone tube of 23 mm diameter, pulsatile flow at a mean flow rate of 4 L/min). A rheolytic thrombectomy system (Hydrolyser) was used with a 9 Fr guiding catheter to remove the clots. The effluent was passed through filters of different size and the amount of embolized particles as well as the remaining thrombus were measured. RESULTS: Thrombus removal rates ranged from 85% to 100%. Embolization rates between 47% and 60% were calculated for the different filters. CONCLUSION: The Hydrolyser is able to remove sufficiently high amounts of thrombus from temporary vena cava filters. However, the amount of embolized particles makes it impossible to utilize this method without special precautions against embolization.

Animals↗

PubMedDate not supplied

Magnetic resonance angiography of nonferromagnetic iliac artery stents and stent-grafts: A comparative study in sheep.

PURPOSE: To compare nonferromagnetic iliac artery prostheses in their suitability for patency monitoring with magnetic resonance angiography (MRA) using conventional angiography as a reference. METHODS: In experiment 1, three Memotherm stents were inserted into the iliac arteries of each of six sheep: two "tandem" stents on one side and a single stent on the other side. In experiment 2, four prostheses (normal and low-porosity Corvita stent-grafts, Memotherm, ZA-stent) were inserted in each of 11 sheep. Patency was monitored before and 1, 3, and 6 months after insertion with 3D phase-contrast and two 2D time-of-flight sequences (TOF-1: TR/TE = 18/6.9, TOF-2: 13/2.5) with and without contrast at 1.5 T. On 206 coronal MIP images (72 pre-, 134 post-stenting), three readers analyzed 824 iliac segments (206 x 4) for patency and artifacts. RESULTS: There was no difference in the number of artifacts between tandem and single iliac Memotherm stents. The ZA-stent induced significantly fewer artifacts than the other prostheses (p < 0.00001). With MRA, patency of the ZA-stent was correctly diagnosed in 88% of cases, which was almost comparable to nonstented iliac segments (95%), patency of the Memotherm stent in 59%, and of the Corvita stent-grafts in 57% and 55%. The TOF-2 sequence with contrast yielded the best images. CONCLUSION: MRA compatibility of nonferromagnetic prostheses depends strongly on the design of the device. MRA may be used to monitor the patency of iliac ZA-stents, whereas iliac Memotherm stents and Corvita stent-grafts appear to be less suited for follow-up with MRA.

Animals↗

PubMedDate not supplied

Effects of lithotripsy on rat kidney: evaluation with MR imaging, histology, and electron microscopy.

Magnetic resonance (MR) imaging at 1.5 T was used to evaluate the effects of extracorporeal shock wave lithotripsy (ESWL) in 30 rats and the findings on T1- and T2-weighted (spin echo 600/22, 1,600-2,000/90) images were compared with histology and scanning microscopy. The observed pathologic changes increased in severity with the number of shock waves given (500-5,000 15 kV). Post-ESWL MR findings in 54 kidneys included perirenal and subcapsular fluid (n = 30), diffuse loss of corticomedullary junction definition (n = 28), intrarenal foci of increased (n = 7) or decreased (n = 6) signal intensity, focal indentation of the renal contour (n = 5), and loss of distinction between the renal, splenic, or hepatic contour (n = 7). The subcapsular and intrarenal findings corresponded pathologically to areas of hemorrhage and hematoma formation--the contour changes to foci of renal scarring or perirenal adhesions. Electron microscopy demonstrated marked alterations of the renal tubules and vasculature. The study shows the feasibility of assessing the nature and chronology of renal damage post-ESWL in a rat model by MR.

Animals↗

PubMedDate not supplied

Circular spirit level guidance system for CT- and MR-guided punctures.

A circular spirit level guidance system was tested for control of CT- and MR-guided punctures. The device consists of a needle holder fixed to a ground plate and two protractors. This allows adjustment of the fixed needle according to the angulation of the supposed puncture path as measured on tomographic images. A circular spirit level is fixed to the needle and leveled. Now the needle can be removed from the needle holder; by leveling the circular spirit level during the puncture, the formerly adjusted angulation is achieved. The system was tested in vitro and in vivo (22 patients) under CT and MR guidance. The average needle deviation was measured to be 1.96 degrees in vitro and 2.51 degrees in vivo. This simple device allows accurate puncture under CT and MR guidance.

Humans↗