Neuroimaging clinics of North America
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Diffusion-weighted imaging of the musculoskeletal system including the spine is a new MR imaging method. Several studies have shown significantly different diffusivities for various pathologic conditions such as edema and tumor. The specificity of diagnosis may be increased and therapeutic effects may be monitored. ⋯ In general, those patients do not pose problems in differential diagnosis. New sequence developments and higher magnetic field gradients should be able to increase spatial resolution and decrease problems from motion artifacts. Studies with larger patient groups and sequences that quantify the results with ADCs are the necessary next steps.
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Diffusion-weighted imaging is of limited value in the MR imaging diagnosis of various tumor pathologies, except in differentiating between dermoids/epidermoids and arachnoid cysts. Diffusion tractography, on the other hand, allows accurate depiction of important white-matter tracts adjacent to brain tumors. This technique uses data derived from diffusion tensor imaging.
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Laser ablation of cerebral tumors is an alternative to surgical excision and radiosurgery; however, more clinical testing is necessary. Various MR parameters can be used during laser ablation to detect structural as well as temperature changes in near real-time for diagnostic and therapeutic applications. Unfortunately, MR-guided ablation does not solve the problem of defining a precise target in high-grade tumors of the central nervous system.
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Neuroimaging Clin. N. Am. · Nov 2001
ReviewOptimizing brain tumor resection. Midfield interventional MR imaging.
The development of the intraoperative MR imager represents an important example of creative vision and interdisciplinary teamwork. The result is a remarkable tool for neurosurgical applications. MRT allows surgical manipulation under direct visualization of the intracranial contents through the eye of the surgeon and through the volumetric images of the MR imaging system. ⋯ Those limits are much tighter around the domain of tool manipulation, where the surgeon will yield, early on, to the enhanced performance of robotics and other technical adjuncts. The era of large open magnet imaging systems for surgical procedures then will come to a close; however, the grander era of the surgeon's integration of precision-guided, multimodality therapeutics will just be beginning. The future will be very bright, indeed.
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Neuroimaging Clin. N. Am. · Nov 2001
ReviewThermal therapies in interventional MR imaging. Focused ultrasound.
MR image-guided focused ultrasound (FUS) provides an entirely noninvasive approach for local thermal therapies. MR imaging allows target definition and continuous temperature mapping. ⋯ Phased-array ultrasound technology will further help the development. MR imaging/FUS may be applied not only for tissue ablation, but also for local drug delivery, gene therapy, and drug activation.