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- 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 onT2-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)