Resonance MR Scan

Because of the ability to image directly in three orthogonal planes (horizontal, sagittal and coronal) MR imaging simplifies the assessment of some clinical problems involving the region of the craniovertebral junction (Hawkes et al. 1983). 

Sagittal MR scan in patients with basilar invagination shows associated brain stem deformity. Chiari malformation and other abnormalities of the craniovertebral junction are also demonstrable (Bradley 1984). 

In rheumatoid arthritis the narrowing of the foramen magnum by subluxation of Ci and C2 can be visualized. Moreover, a mass with soft tissue signal intensity can be seen posterior to the dens in the region of joint synovium and transverse ligament (Modic et al. 1984). 

Because cortical bone gives a zero signal bone defects are difficult to delineate. However, cancellous bone, with a marrow cavity within the vertebral bodies, exhibits high signal intensity. In tumours of the vertebral bodies destruction and marrow replacement by tumour significantly alters the signal intensity, collapse of the body may be seen and the associated paraspinal mass visualized (Han et al. 1983). 

There are however, certain limitations of this new investigation at present. Access to MR scanners is fairly limited in many countries. Considering also the fact that bony details are not readily shown on MR, conventional X-ray methods and bone window images an CT are unlikely to became absolate. 

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Functional drug carriers Magnetic resonance (MR) scanning (nanoparticles)... 

Fig. 2.4a-c. CT (a) and sagittal Tl-weighted magnetic resonance (MR) (b) scan of another brain-stem cavernoma. Due to its calcification, it is easy to see even on the CT scan. The MR nicely reveals the typical cavernoma pattern with the dark rim of hemosiderin. Note that the acute hemorrhage occurred at the dorsal aspect of the cavernoma and now facilitates easy surgical removal. A view through the microscope while removing the cavernoma (c). Note the typical mulberry aspect of the malformation... 

Fig. 6. Prostate biopsies following radiation therapy. >H MR spectra (8.5 T, 37°C), of irradiated prostate biopsy specimens (a) positive for malignancy (time post-radiotherapy (XRT) 36 months, local failure) (b) negative for malignancy (time post XRT 20 months). MR spectra where collected with presaturation of the water signal using low-power continuous irradiation. Acquisition parameters include number of scans 640, sweep width 5000 Hz, delay 2.41 s and time domain data points 4K. Reprinted from International Journal of Radiation Oncology, Biology and Physics, 50, C. Menard, I. C. P. Smith, R. L. Somoijai, L. Leboldus, R. Patel, C. Littman, S. S. Robertson and T. Bezabeh, Magnetic resonance of the malignant prostate, p. 317, Copyright (2001), with permission from Elsevier Science.

V)oreover, spectroscopic techniques are frequently applied in medicine. For example, magnetic "Resonance imaging (MRI) works on the principle of N MR. and is used to scan for tumours in the brain. It is also used by scientists trying to understand the functioning of the brain. 

There is equipment already in use which can carry out whole-body scans, and combine H MRI with 3 P MRS. Instrumentation is presently undergoing vay rapid development and it seems not unlikely that the two techniques (both utilising P resonance) will become leading methods for the diagnosis of disease, assessment of drug effects and the observation of the results of surgery, etc. Widespread application and use has so far been somewhat limited by the high initial cost of equipment. 

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