Figure 3. Thoracic spine short tau inversion recovery (STIR) MRI, coronal view. The Pancoast tumor (P) is visible as an abnormal, hyperintense mass in the medial right lung apex, superior mediastinum, and superior sulcus with associated vertebral infiltration which is visible from the spinal levels T2 (upper arrow) through T6 (lower arrow). Although the mass approximates the brachial plexus, which is faintly visible in the area within the dotted line, the extent of plexus involvement is difficult to evaluate as it is not well delineated in this thoracic MRI series. The mass measures 7.5 centimeters in the transverse plane (measurement not shown).