1. The answer is D. Without radicular or neurologic signs, conservative management is the initial management of simple low back pain. With radicular signs or altered neurologic exam, an MRI is the test of choice.

2. The answer is B. A presence of an implanted intrathecal pumps used for pain, such as the Medtronic SynchroMed™ pump, is not an absolute contraindication to MRI. The pump itself may stop functioning during the MRI exposure, but will resume thereafter. It is recommended that the pump programming be checked immediately after the MRI to verify that it has not been altered.

3. The answer is C. Although classically advocated for use in identifying Complex Regional Pain Syndrome, a regular single-phase bone scan is equally effective for the diagnosis of this condition. Triple-phase bone scan is an imaging modality that is more useful for osteomyelitis. A triple-phase bone scan, as its name implies, has three phases: a dynamic phase (performed immediately after radiotracer injection), a blood pool phase (performed 3-5 min after injection), and a delayed bone phase (performed 2-6 h after injection). In this scan, both blood flow and bone turnover are also evaluated as opposed to evaluation of only bone turnover in a plain bone scan. In the dynamic phase, the general amount of blood flow to an area is determined; in the blood pool phase, the amount of extravasation of tracer into the surrounding tissue is detected. In the delayed phase, bone uptake is measured. Because infections lead to increased blood flow in the area of infection as well as leaky tissue (osteomyel-"¿fe"), the two initial phases of a three-phase bone scan are useful in their diagnosis. The final phase, the delayed bone scan phase, localizes this infection to the bone ("osfeo"-myelitis) by demonstrating increased bone turnover. Fractures and metastases as well as infections may cause hyperperfusion and hyperemia resulting in positive three-phase bone scans. When diagnostic doubt exists and greater specificity is needed, a subsequent scan using indium-111-tagged leukocytes will be positive for infection but not the other conditions. In this scan, leukocytes are withdrawn from a patient, labeled with indium-111, and re-injected. Detection is performed 24 h later with the hope that these labeled leukocytes will concentrate at an area of infection.

4. The answer is C. Ultrasound uses high-intensity sound waves in the range of 220 MHz to generate images of internal structures. It is attractive in that it is portable, and images can be achieved in real time. Furthermore, this modality does not employ ionizing radiation or contrast agents, thus minimizing side effects and damage. 5. The answer is D.

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Back Pain Revealed

Back Pain Revealed

Tired Having Back Pains All The Time, But You Choose To Ignore It? Every year millions of people see their lives and favorite activities limited by back pain. They forego activities they once loved because of it and in some cases may not even be able to perform their job as well as they once could due to back pain.

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