Abstract
The objective of imaging in plasma cell dyscrasia staging is the detection of osteolytic bone lesions and associated soft tissue masses. In 2012, we initiated a project comparing skeletal surveys using conventional radiography and low-dose CT of equal radiation dose.
The end-points included clinical benefit (detection of osteolytic lesions, vertebral compressions), patient comfort, radiation exposure and cost. Seventy-four patients underwent both examinations on the same day.
CT showed the presence of osteolytic lesions in 14% of patients with negative finding on radiography and excluded lesions found by radiography in 14% of patients. Conventional radiography detected only 72% of vertebral compressions depicted on CT (p < 0.05).
CT moreover demonstrated the additional 31 potentially important extra-skeletal findings. The radiation exposure was 2.7 mSv for CT and 2.5 mSv for radiography (n.s.).
The in-room time for radiography was 41 +- 7 min compared to 6 +- 2 min for CT (p < 0.0001). The results of this study demonstrated the difference in diagnostic power between low-dose CT skeletal survey and radiography based skeletal survey for the detection of osteolytic skeletal involvement and extra-skeletal lesions in patients with plasma cell dyscrasias.
Low-dose CT can be performed with similar radiation exposure, in the same extent, at lower cost, with significantly superior patient comfort and with improved certainty of the diagnosis. This study confirms the recommendation to include low-dose CT skeletal survey as the new "gold-standard" in the diagnostic workup of multiple myeloma.