The usefulness of MR subtraction technique in metastatic spinal cancer

Abstract

In this study, the authors examined the usefulness of subtraction techniques in vertebral cancer patients by comparing contrast enhanced images with before/after contrast enhancement subtraction images. In patients with metastatic vertebral cancer, contrast enhanced images and subtraction images were acquired in sagittal and axial planes. On sagittal planes, between the first and the fifth lumbar vertebrae, in three areas of metastatic vertebral cancer and in areas above and below areas with vertebral cancer, signal to noise ratios (SNRs) and contrast to noise ratios (CNRs) were measured. On axial planes, in five vertebral cancer areas, right and left vertebral arches, and right and left longest muscle areas, SNRs and CNRs were also measured. In sagittal planes, when images were divided into contrast enhanced images and subtraction images, SNRs were relatively decreased in the areas above and below vertebral cancers. On axial planes, SNRs were relatively reduced in the right and left vertebral arch and right and left longest muscle areas. On both sagittal planes and axial planes, CNRs were relatively increased in areas with vertebral cancer, and relatively increased on subtraction images. This study shows that before/after contrast enhancement subtraction images can be used for the evaluation of malignant tumours in metastatic spinal cancer.

Keywords:

• contrast enhanced imaging
• subtraction imaging
• signal to noise ratio
• contrast to noise ratio