Fig 1.

Patient 21, a 62-year-old man who was previously treated for squamous cell carcinoma of the floor of the mouth with primary and level I lymph node resection at an outside institution.

A, Coil-corrected axial view fast spin-echo T2-weighted image with fat saturation (4000/90/4) shows pathologically enlarged left neck nodes in level IIA and superficial to the sternocleidomastoid muscle (white arrows). The level IIA node shows internal areas of irregular low signal intensity (arrowheads), an appearance we would describe as nodal heterogeneity but not nodal necrosis. Note that it would be impossible to exclude these small, irregular areas from region of interest analysis. Also note the soft tissue deformity and absence of the ipsilateral submandibular gland due to previous resection.

B, Coil-corrected axial view contrast-enhanced T1-weighted image with fat saturation (600/20/2), obtained at the same level as that shown in A, shows slightly irregular enhancement of both nodes, with the irregularity clearly more pronounced in the level IIA node. Both nodes were pathologically confirmed to be tumor-involved.