Bone Magnetic Resonance Imaging Research Articles

Magnetic Resonance Imaging of Bone and Soft Tissue Tumors and Their Mimics

Magnetic Resonance Imaging of Bone and Soft Tissue Tumors and Their Mimics

Magnetic Resonance Imaging of Bone and Soft Tissue Tumors

The clinical utility of the magnetic resonance imaging (MRI) as compared with that of computed tomography (CT) and plain radiographs in patients with bone and soft tissue tumors is reported. Seven patients with soft tissue tumors (desmoid, lipoma, giant cell tumor of the tendon sheath, hemangioma, extraskeletal chondroma and synovial sarcoma), one patient with pigmented villonodular synovitis (PVS), and three patients with bone tumors (chondroblastoma, osteosarcoma and metastatic bone tumor) were examined with a Signa 1.5-tesla superconducting magnet, CT scan and plain radiographs. Advantages of MRI over CT and plain radiographs were as follows: (1) the ability to image in the sagittal, coronal and oblique planes, (2) demonstration of vessels, nerves and tendons without contrast, (3) demonstration of hemosiderin in PVS, and (4) demonstration of the intramedullar and extraosseous extent of bone tumors. However, MRI was less valuable than CT and plain radiographs for cortical destruction and small calcification.

Magnetic resonance imaging of bone after radiation

Magnetic resonance imaging (MRI) was performed in 22 patients at various times (0–3) years) following radiation therapy to the spine. T 1 and T 2 weighted images were obtained at 0.5 Tesla. Increased signal was seen after 800–6000 rads (8–60 Gy). Marrow effects corresponded to radiation ports. Recurrent tumor was clearly separated from fatty replacement. This was much better seen on T 1 weighted images. Five patients that had MRI during their course of radiotherapy (XRT) did not have increased signal on T 1 images of the bone marrow. The earliest fatty marrow changes was seen nine days following completion of 3000 rads (30 Gy) XRT over one month's duration. One patient who received 800 rads (8 Gy) to the upper thoracic spine for eosinophilic granuloma had no radiation effects on MRI when imaged 16 days following completion of XRT given over five days. Fatty marrow change was seen in this patient on MRI six months later. MRI was particularly useful in defining the extent of prior radiation effects when repeat therapy was needed.

MRI and CT evaluation of primary bone and soft-tissue tumors.

Twenty-six patients with primary tumors of bone or somatic soft tissues underwent both magnetic resonance imaging (MRI) and computed tomography (CT); 15 of the patients had radionuclide bone scans as well. Only in a minority of cases did these tomographic methods provide information needed for diagnosis that could not be derived from the plain radiographs alone; however, for assessing the extent of the disease, both CT and MRI proved very valuable, particularly MRI. Specifically, MRI was superior to CT in delineating the extent of the neoplasms and their relation to surrounding structures in 21 of the patients, equal in four, and inferior in only one. Furthermore, in the 13 patients with tumors of long bone, MRI was judged superior to CT in visualizing marrow abnormality in 12 cases, and equal in only one case. Radionuclide scans demonstrated the lesions in 14 of the 15 cases; its primary utility was in excluding additional lesions. It is concluded that for these patients, MRI was the imaging method of choice in assessing the extent of bone and soft-tissue tumors.