Renal cell carcinoma
Magnetic Resonance Imaging (MRI) scans provide an image of the soft tissues in the body using radio waves and strong magnets. MRI can be used instead of CT if the patient exhibits an allergy to the contrast media administered for the test. Sometimes prior to the MRI scan, an intravenous injection of a contrasting material called gadolinium is given to allow for a more detailed image. Patients on dialysis or those who have renal insufficiency should avoid this contrasting material as it may induce a rare, yet severe, side effect known as nephrogenic systemic fibrosis. A bone scan or brain imaging is not routinely performed unless signs or symptoms suggest potential metastatic involvement of these areas.
MRI scans should also be considered to evaluate tumour extension which has grown in major blood vessels, including the vena cava, in the abdomen. MRI can be used to observe the possible spread of cancer to the brain or spinal cord should the patient present symptoms that suggest this might be the case.
Vertebral osteomyelitis
Radiological intervention is often necessary to confirm the presence of vertebral osteomyelitis in the body. Plain-film radiological orders are necessary for all patients displaying symptoms of the disease. This diagnostic approach is often preliminary to other radiological procedures, such as magnetic resonance imaging, or MRI, computed tomography (CT) scan, fine-needle aspiration biopsy, and nuclear scintigraphy. The initial plain-film X-ray images are scanned for any indication of disc compression between two vertebrae or the degeneration of one or more vertebrae. Only when these findings are ambiguous is further testing necessary to diagnose the disease. Other radiological approaches offer more comprehensive imaging of the spinal area, but can often prove inconclusive. MRI scans do not expose the patient to radiation and are highly sensitive to changes in the size and appearance of the intervertebral discs; however, findings on the MRI scan may be confused with other conditions such as the presence of tumors or bone fractures. If MRI imaging is inconclusive, the high sensitivity to erosions in the vertebrae or intervertebral discs of CT scans may be preferred for their ability to indicate signs of the disease more clearly than MRI. Additional tests may be ordered if such preliminary tests cannot confirm a diagnosis; for example, needle biopsies may be needed to take samples of bone surrounding the disc space where the infection is thought to live, or nuclear bone scans may be used to contrast areas of healthy bone with areas of infection.