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Central nervous system
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
T2-weighted imaging of the brain is performed to provide an overview of the brain anatomy and pathology and particularly of the structures of the cerebro-pontine angle. MRI of the inner ear is most frequently performed for diagnosis of vestibular schwannoma following symptoms of one-sided neurosensory hearing loss or tinnitus. T2 high-resolution slices of <1 mm are acquired in the transverse plane. The low signal acoustic and facial nerves are demonstrated in contrast to the surrounding high signal CSF [60]. Image quality in gradient echo imaging may be degraded by magnetic field inhomogeneity inherent to the air/bone/tissue interface of the posterior fossa.
Head and neck
Published in David A Lisle, Imaging for Students, 2012
One of the most common investigations in head and neck imaging is MRI to rule out acoustic neuroma. Acoustic neuroma refers to a nerve sheath tumour of CN8. These tumours are schwannomas, not neuromas, and usually involve the vestibular component of CN8, so ‘vestibular schwannoma’ is a more pathologically correct term. Vestibular schwannomas usually present in adults with slowly progressive unilateral SNHL, sometimes associated with tinnitus and vertigo. Vestibular schwannomas vary in size and are often quite small.
Health Effects of Chronic Exposure to Radiation From Mobile Communication
Published in Marko Markov, Mobile Communications and Public Health, 2018
A report has recently been released from The National Toxicology Program (NTP) under the National Institutes of Health (NIH) in USA on the largest ever animal 2-year study on cell phone RF radiation and cancer (64). Rats were exposed to either GSM- or code-division multiple access (CDMA)-moduleated signals at 900 MHz beginning in utero (SAR 0, 1.5, 3, 6 W/kg, 9 h per day, 10 min on/off, 7 days per week). An increased incidence of glioma in the brain and malignant schwannoma in the heart was found in rats at all SAR values and both types of signal. This effect was statistically significant in males only. A statistically significant SAR-dependent trend for GSM and CDMA exposures in males was found. Comet assay showed a statistically significant increased trend and SAR-dependent increase of DNA damage in the frontal cortex of males. Acoustic neuroma or vestibular schwannoma is a similar type of tumor as the one found in the heart, although it is benign. Thus, this animal study supported human epidemiological findings on chronic exposure to RF radiation and brain tumor risk (5,65,66). The strength of the NTP study is in its: (i) long term exposure covering in utero period and comparable with life span, (ii) usage of GSM/CDMA modulations and intermittent exposure that is close to exposure from mobile phones in real life, and (iii) large animal group providing high statistical power. The limitation of this study is in using only one GSM and one CDMA frequency, 900 and 1900 MHz, respectively, from multiple frequency channels used in mobile communication. The previously reviewed data showed frequency dependent effects of nonthermal RF (8). In particular, our studies showed that the mobile phone frequency channels vary in their efficiency to affect human cells (67–69). In particular, the frequency of 915 MHz was shown to affect the blood brain barrier and inhibit DNA repair in rats and human cells, respectively. The frequency of 905 MHz was much less effective in experiments with human cells. Thus, some of mobile phone frequency channels may be more or less detrimental. The usage of only two frequencies from GSM/CDMA mobile communication in the NTP study might underestimate carcinogenic effects from everyday exposures to mobile phone RF at various frequency channels. The finding that increased cancer risks was revealed in RF-exposed males only is not a limitation of this study. According to IARC, ‘“the probability that tumors will occur may depend on the species, sex, strain, genetic background, and age of the animal, and on the dose, route, timing, and duration of the exposure. Evidence of an increased incidence of neoplasms with increasing levels of exposure strengthens the inference of a causal association between the exposure and the development of neoplasms.” p. 22 (4).
Device profile of the MED-EL cochlear implant system for hearing loss: overview of its safety and efficacy
Published in Expert Review of Medical Devices, 2020
Uwe Baumann, Timo Stöver, Tobias Weißgerber
Preoperative imaging cannot always be used to reliably determine the actual accessibility of the cochlear lumen. In difficult cases as inner ear malformations or vestibular schwannoma, the use of intraoperative intra-cochlear test electrodes is recommended. The insertion test tools may be used during inner ear surgery to assess the condition of the cochlea. This information can be used for selecting the best suited cochlear implant electrode variant in terms of insertion depth vs. the number of contacts inserted [11].
RESNA position on the application of ultralight manual wheelchairs
Published in Assistive Technology, 2023
Lynn A. Worobey, Jennith Bernstein, Joseph Ott, Theresa Berner, Jaqueline Black, Mary Cabarle, Tina Roesler, Sage Scarborough, Kendra Betz
MK is a 54-year-old female with a medical history significant for chronic inflammatory demyelinating polyneuropathy (CIDP) for 12 months with associated bilateral upper and lower limb weakness, balance impairment with associated falls (5 within the past 12 months), fatigue, neuropathic pain (distal upper and lower limbs), chronic low back pain due to spondylosis and spinal stenosis, vestibular schwannoma following right-sided craniectomy with resection and residual balance deficits and right-sided hearing loss.