Osteoblastoma
When diagnosing osteoblastoma, the preliminary radiologic workup should consist of radiography of the site of the patient's pain. However, computed tomography (CT) is often necessary to support clinical and plain radiographic findings suggestive of osteoblastoma and to better define the margins of the lesion for potential surgery. CT scans are best used for the further characterization of the lesion with regard to the presence of a nidus and matrix mineralization. MRI aids in detection of nonspecific reactive marrow and soft tissue edema, and MRI best defines soft tissue extension, although this finding is not typical of osteoblastoma. Bone scintigraphy (bone scan) demonstrates abnormal radiotracer accumulation at the affected site, substantiating clinical suspicion, but this finding is not specific for osteoblastoma. In many patients, biopsy is necessary for confirmation.
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.