MR tracking of a vascular guidewire sized for a .035-inch (.89-mm) catheter lumen was performed. The guidewire was actively tracked by incorporation of a miniature radiofrequency (RF) receive coil built into its tip. After in vitro validation, simultaneous tracking of the guidewire and a catheter was performed in the aortic and abdominal vessels of a swine at 1.5 T. The ability to track such a small device and the ability to simultaneously track multiple devices are significant steps towards vascular interventions under MR guidance.

Animals↗

PubMedDate not supplied

MR-guided percutaneous angioplasty: assessment of tracking safety, catheter handling and functionality.

PURPOSE: Magnetic resonance (MR)-guided percutaneous vascular interventions have evolved to a practical possibility with the advent of open-configuration MR systems and real-time tracking techniques. The purpose of this study was to assess an MR-tracking percutaneous transluminal angioplasty (PTA) catheter with regard to its safety profile and functionality. METHODS: Real-time, biplanar tracking of the PTA catheter was made possible by incorporating a small radiofrequency (RF) coil in the catheter tip and connecting it to a coaxial cable embedded in the catheter wall. To evaluate potentially hazardous thermal effects due to the incorporation of the coil, temperature measurements were performed within and around the coil under various scanning and tracking conditions at 1.5 Tesla (T). Catheter force transmission and balloon-burst pressure of the MR-tracking PTA catheter were compared with those of a standard PTA catheter. The dilatative capability of the angioplasty balloon was assessed in vitro as well as in vivo, in an isolated femoral artery segment in a swine. RESULTS: The degree of heating at the RF coil was directly proportional to the power of the RF pulses. Heating was negligible with MR tracking, conventional spin-echo and low-flip gradient-echo sequences. Sequences with higher duty cycles, such as fast spin echo, produced harmful heating effects. Force transmission of the MR-tracking PTA catheter was slightly inferior to that of the standard PTA catheter, while balloon-burst pressures were similar to those of conventional catheters. The MR-tracking PTA catheter functioned well both in vitro and in vivo. CONCLUSION: The in vivo use of an MR-tracking PTA catheter is safe under most scanning conditions.

Angioplasty, Balloon↗

PubMedDate not supplied

Fistula of stapes footplate caused by pulsatile cerebrospinal fluid in inner ear malformation.

Congenital malformations of the inner ear are well described, though the combination with cerebrospinal fluid (CSF) leaks remains controversial. In this paper a case of a bilateral Mondini malformation with a CSF otorrhea on one side is reported. The malformed stapes contains a perforation in the middle of the footplate and associated thinning analogous to a pothole in a mountain stream. The histological findings support the hypothesis of pulsatile flow of CSF as origin of the perforation of the footplate.

Cerebrospinal Fluid Otorrhea↗

PubMedDate not supplied

Uncommon morphologic characteristics in Leigh's disease.

We describe a 4-month-old male patient with severe developmental delay and elevated lactate in blood and CSF. The MR images showed abnormalities differing from the typical pattern found in association with Leigh's disease. The examination of fibroblast cultures showed diminished activity of mitochondrial complexes I and III. The patient died at the age of 9 months.

Developmental Disabilities↗

PubMedDate not supplied

Noninvasive direct stimulation of the cochlear nerve for functional MR imaging of the auditory cortex.

We herein present our preliminary experience with functional MR imaging of the direct electrical stimulation of the cochlear nerve using an MR imaging-compatible electrode placed in the external auditory meatus of five patients with binaural sensorineural hearing loss. The stimulator was placed outside the imager's bore, and the electrode produced virtually no susceptibility artifacts. In three of five patients, it was possible to activate the superior temporal gyrus during functional MR imaging. No side effects were observed.

Auditory Cortex↗

PubMedDate not supplied

[Effect of temperature on the glycolysis and respiration of Ehrlich's tumor ascites cells].

Explore the source record for details and available documents.

Adenosine Triphosphate↗

PubMedDate not supplied

[The "Freiburg Spinal Study"--epidemiology of occupationally-induced spinal diseases of health care employees in Germany].

Musculoskeletal diseases are very common in modern societies. As several international investigations have shown that the etiology of these diseases is correlated with working conditions in some professions. With financial subsidy by the German insurance company for the regulation and compensation of occupational diseases in the health care sector (BGW), we investigated in 6 different projects the possible relation of working conditions and musculoskeletal diseases among health care professionals, esp. nurses. Our contribution describes the design of the different sub-projects and presents some results. The summarising discussion points out that there was a strong tendency in all sub-projects to confirm the hypothesis that nurses run a significantly higher risk to suffer from work-related musculoskeletal diseases and disorders. The results of the sub-project "cohort study in nursing pupils" support this hypothesis. The results do not only supply important background information for the process of compensating occupational diseases in this field but also indicate a tremendous personal and structural need for more and better prevention.

Adult↗