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SAMPLE RECENT RESEARCH
Use of MR proton spectroscopy (1H MRS) to evaluate bone. 1H MRS portrays bone marrow with two prominent peaks: water and lipid. We use the lipid-to-water ratio (LWR) as measurements for quantifying bone changes. In young subjects, the LWR is small (under 0.6) in older subjects the LWR is higher (above 0.6).
I) Bone Spectroscopy
We have found that in patients with osteoporosis the LWR tends to be high as the bony trabecula rarefy and fatty marrow settles in the bone resorption cavities.
Below: This is illustrated here in a patient with osteoporosis and associated compression fractures (left). This patient's bone 1H MRS shows the lipid peak to be high (right).
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Below: This patient had radiation therapy to the thoracic spine. The MRI shows the thoracic and upper lumbar vertebrae white on T1 weighted MR images. This denotes conversion of red marrow to fatty marrow as a result of radiation. The image on the right shows the lipid peak to be huge compared to the water peak.
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Below: Bone proton 1H MRS has potential use in quantifying treatment response in patients treated for proliferative bone marrow processes such as multiple myeloma, leukemia and lymphoma. This patient has multiple myeloma. Left: Normal marrow is replaced with malignant tissue. The bone on this T1 weighted MRI appears darker than usual. The 1H MRS on the right shows the second peak (lipid peak) to be totally suppressed and the water peak is very large. With appropriate treatment the water signal will decrease and the lipid signal will increase.
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II) Spine Imaging
It is presently not widely known that low back pain and sciatica are often caused by degenerative/inflammatory disease of the facet joints. We have shown that these disease processes are best shown with fat suppression and with contrast enhancement. The above image (fat suppressed and contrast enhanced) of the lower lumbar spine facet joints exhibit intense inflammatory changes at and around the right L4/5 facet joint (bright signals on viewer's left).
III) Brain diffusion
Perfusion imaging helps define areas of over- or under perfusion. Determination of blood perfusion is critical to determine salvageable brain tissue in patient with strokes. Perfusion requires an intravenous injection of contrast material. This often delays perfusion measurements. The images shown here were taken on a 7 Tesla research animal scanner located at GICCS.
This is a study of a tumor implanted into a rat's thigh. We are using a new experimental MRI sequence that does not require an intravenous bolus injection. In the example below, a flow-sensitive Alternating Inversion Recovery (FAIR) sequence was used to acquire a perfusion image. The black areas are regions of decreased blood flow (decreased perfusion) in parts of the tumor.