- Discussion:
- useful in planning surgery & limb salvage procedures;
- assists w/ preop planning for relationship of tumor to such adjacent normal structures as physes, joints, & N/V bundles;
- Soft Tissue Tumors:
- specificity of MRI is poor;
- for planning limb salvage prosthesis, distance from the proximal aspect of the lesion to joint space;
- lesions w/ in fat are usually shown better in
T1 images;
- lesions within
Muscle are better shown on
T2-wt images;
- look for an inhomogeneous signal on
T1 images;
- Bone Tumors:
- CT is also superior in detecting subtle soft-tissue calcification;
- CT is superior for evaluating cortical changes & for flat bones w/ little marrow;
- for planning limb salvage prosthesis, distance from the proximal aspect of the lesion to joint space;
- shows intramedullary and extramedullary anatomy;
- Spinal Tumors:
- useful for showing vertebral involvement by metastatic disease
- normal fatty marrow is replaced by tumor which has a higher water content (and therefore T1 signal changes from
high to low and T2 signal changes from low to high);
