Early MR demonstration of spinal metastases in patients with normal radiographs and CT and radionuclide bone scans

Forty patients with known primary tumor and progressive back pain, suspected of having spinal metastatic disease, underwent magnetic resonance (MR) examinations of the thoracic and lumbosacral spine. Conventional radiographs and CT scans of the spine were all normal. The radionuclide bone scans were equivocal. In 21 patients focal or diffuse vertebral MR abnormalities were detected. In nine patients the lesions were hypointense on T1 sequence, and the same lesions were demonstrated poorly or not at all on T2 and proton density sequences. In eight other patients the bone marrow metastases presented with strong signal intensity on T2 and were poorly or not at all demonstrated on T1 and proton density sequences. In three patients with multiple myeloma, the signal intensity pattern of the vertebrae was diffusely heterogeneous, with alternating small foci of strong and weak signals (a mosaic-like pattern). Following the MR studies, needle biopsy confirmed the malignancy in the 21 patients who had shown abnormalities. No correlation between the type of primary tumor and the signal intensity of the vertebral metastases was shown. Possibly the mosaic pattern shown in three of the multiple myeloma patients represents a special case.