Ultrasound also plays a role in the evaluation of synovial fluid in tendons. Dynamic ultasound permits visualization of the normal flow of synovial fluid along tendon sheaths as well as determining how disruptions of flow are associated with manifestations of various pathologic conditions. We are currently engaged in a most interesting study that utilizes ultrasound to determine whether or not non-cardiovascular exercise (e.g. walking downstairs) can provoke joint effusion.
Diabetic Feet
Diabetes leads to over 95% of nontraumatic lower extremity amputations. The direct cost of this disorder to society is estimated to be $10 billion/year. In addition, the population of patients with diabetes is unfortunately increasing rapidly, promising an enormous public health problem in the next three decades.
Until relatively recently most diabetics were imaged by plain films or nuclear scintography. Difficult clinical assessment and poor imaging resulted in many unnecessary amputations. The amputation itself accentuated the problem. Once a foot is resected the contralateral foot loses its ability to withstand pressure, thus leading to a large incidence of bilateral amputations.
Dr. Schweitizer and his group performed original research on imaging the diabetic foot with MR. They described the various imaging findings in this disorder as well as how to differentiate an infection from neuropathic disease. A series of critical questions were posed and answered. Why do reactive changes occur? What is the effect of vascularity? How does this vascularity differ between soft tissue and bone? Can contrast aid in these discriminations? Are the tendons involved in diabetic feet? Why are some joints particularly affected, and other joints preserved? Can we predict if and at what location a patient needs to be amputated? Can we effectively follow treatment?
Dr. Sandra Moore is now engaged in research to better understand the neuropathic part of diabetic pedal disease. Her particular focus is understanding when ligamentous injuries occur, and the cascade of pathological events. What is the true staging of neuropathic disease? Amazingly, after 60 years of studying diabetic pedal disease, this is still not clear. Dr. Moore is planning on extending the early work we have reported on vascularity and diabetes to a more advanced model, exploiting the signal-to-noise and functional imaging advantages of the 3T and 7T MR units to aid in furthering the understanding of this disorder. The anterior tibialis muscle will serve as a model for assessment of diabetic vasculopathy in this research.
It is interesting that, concurrent with utilization of advanced imaging techniques such as MRI, we may, indeed, have come full circle as scintigraphic evaluation using a new white cell labeling agent (NeutraSpec) may overcome some of the early difficulties with indium scanning and confer high specificity to evaluation of the diabetic foot.
Fat
When we speak and write about the musculoskeletal system we predominantly focus on bone, cartilage, tendon and ligament, and perhaps to a lesser degree on muscle. What has been commonly neglected in muscloskeletal research is fat. Fat has been forsaken because traditionally it has been considered primarily or exclusively an energy store, with little other purpose. Our body fat, in fact, has three purposes. One of them, as just stated, is as an energy store. In addition, fat likely is a space holder in some locations, with its size dependent upon the size of the structures around it. This would apply to intramuscular, epidural, and subfascial fat. Our group has reported this in the spine. However, underappreciated is the concept of mechanical fat or fat that provides a functional advantage. This was first described by Hoffa one hundred years ago in his original description of the fat pad in the knee, and has just been rediscovered, becoming a focus of our research. We recently performed a study comparing the size of Hoffa’s fat pad in patients based upon body weight, body height, body mass index, and percentage of body fat, and found that in most cases the size of Hoffa’s fat pad was independent of patient habitus. This implies that Hoffa’s fat is not an energy store. Further investigation utilized flexion-extension images with comparison to a cadaver via shape analysis. We learned that there is a functional role to the fat pad, and are currently performing a detailed shape analysis of Hoffa’s fat pad to determine if the shape can be a window into this anatomic structure.
Subcutaneous fat, particularly in the heel fat pad, is another important area of functional mechanics. This fat pad is thought to be an instigating factor in diabetic foot disease. We plan to complete an analysis of this fat pad in normal individuals and patients with neuropathic feet, thus combining our interests in diabetes and muscular fat. Fat is important in the synovium where fat hypertrophy is a response to synovitis. The converse is also true that the absence of fat implies synovial disease such as adhesive capsulitis or rotator cuff tears. This is another future direction for our research.
Shape
The musculoskeletal system is the only portion of the body where shape has an almost absolute influence on function and mechanics. This cannot be overemphasized. It is the primary factor in developmental dysplasia of the hip, in tracking disorders of the patellofemoral joint, as well as many, many other diseases. We have performed several detailed shape analyses using a mathematical construct similar to what Dr. Leon Axel utilized in the heart, applying this to the shoulder and knee. Our group reported one of the first studies to show that the undersurface of the acromion is actually not a predictor of shoulder impingement; impingement may be more of a dynamic phenomenon than a static phenomenon predicated by the shape of the acromion.
<< Previous Page
>> Next Page
Page:
1
2
3