Computed tomographic images were generated using collimated microwaves of frequency 10.5 GHz instead of x rays. In the authors' laboratory version of a rotate-translate scanner, the beam is fixed and a phantom is moved between source and detector, the apparatus being suspended in a tank of fluid to provide impedance matching between phantom, source, and receiver. Phantoms consisting of test tubes of water, cylinders of wood, and animal tissues show spatial resolutions of about 2 cm. It is planned to apply the technique first to mammographic examination, which can best utilize the large difference in microwave absorption between fatty and nonfatty tissues.
Transmigration of the mandibular canine is very uncommon, the etiology of which isn't clear. A cuspid is classified as "transmigrated" when it cross the mid-line. We present five instances of transmigrated mandibular canines together with an audit of the writing etiology, clinical highlights, treatment alternatives, case reports and conclusion at the end.
Background:The study was undertaken to determine whether a single slice magnetic resonance (MR) myelogram sequence improves the interpretation and diagnostic yield for magnetic resonance imaging (MRI) of the spine.Methods:A total of 100 cases with positive findings were retrospectively reviewed. All patients had initial imaging with sagittal T1-weighted (T1-W) and T2-weighted (T2-W) scans, followed by axial T2-W images. Subsequently, a heavily T2-W single slice MR myelogram sequence was acquired in coronal and sagittal planes. The MR myelogram images were evaluated initially by a radiologist, and, further independently reviewed, by a neurologist, neurosurgeon, and spine surgeon. The utility of the MR myelogram in establishing the diagnosis was graded on a 4-point scale.Results:Out of 100 cases, 53% showed degenerative spine or disc disease, 14% space occupying lesions, 13%, congenital lesions, 7% infection, and 7% other conditions. The MR myelogram contributed additional information in 50-74% cases. The intraclass correlation coefficient showed overall good agreement between observers in grading the utility of MR myelogram.Conclusion:Single slice MR myelography is noninvasive avoiding the complications associated with lumbar punctures/intrathecal contrast injections, while image acquisition takes only an added 6-8 s. Although MR myelogram has no value as a stand-alone sequence, its inherent advantage is that it completes the overview of the spinal pathology in entirety, and adds vital three-dimensional information in 50-74% of cases.
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