Microscopy Coil for Preoperative MRI of Small Soft-Tissue Masses of the Hand and Foot: Comparison with Conventional Surface Coil

OBJECTIVE. The purpose of this study was to evaluate the usefulness of MRI performed with a microscopy coil in the preoperative evaluation of small soft-tissue masses of the hand and foot. MATERIALS AND METHODS. Sixteen patients with clinically suspected soft-tissue masses of the hand or foot underwent MRI with both a conventional surface coil and a microscopy coil and were included in this study. All MR images were obtained with a 1.5-T system and a 47-mm microscopy coil. MR images were qualitatively analyzed for size, number, location, morphologic details, extent and margin quality, and growth pattern of the mass and the relation between the mass and adjacent anatomic structures. For quantitative analysis, we measured the signal-to-noise ratio of each mass on MR images obtained with both coils. MRI findings with the two coils were compared, and the findings were correlated with the surgical and histopathologic findings on all 16 patients who underwent surgery. RESULTS. Relation between adjacent anatomic structures and the mass (n = 15), internal morphologic features (n = 14), and extent or margin quality (n = 11) of masses were clearly delineated on MRI performed with a microscopy coil (p = 0.0001). These findings correlated well with the surgical and pathologic findings. In addition, small soft-tissue masses not detected with a conventional surface coil were readily detected with a microscopy coil (n = 3). The signal-to-noise ratios of masses detected with a microscopy coil were significantly higher than those of masses detected with a conventional surface coil (p = 0.006). CONCLUSION. MRI with a microscopy coil was useful in the preoperative assessment of small soft-tissue masses of the hand and foot.