Squamous cell carcinoma of the oral cavity: MR findings and value of T1-versus T2-weighted XXXX images.

@entity1 @entity1697 @entity5 @entity957 @entity9468
OBJECTIVE: The purposes of this study were to describe the characteristics of @entity957 of the oral cavity on unenhanced and contrast-enhanced T1-weighted spin-echo (SE) MR images and unenhanced T2-weighted @entity9468 ( @entity9468 ) MR images and to determine which sequences best delineate the margins and extent of the @entity5 . MATERIALS AND METHODS: Forty-four @entity1 with proved squamous cell @entity1697 (tongue, 24; floor of mouth, seven; buccal mucosa, four; maxillary gingiva, two; and mandibular gingiva, seven) underwent unenhanced axial T2-weighted @entity9468 MR imaging and unenhanced and enhanced axial and coronal T1-weighted SE MR imaging. The appearance, signal characteristics, and extent of the @entity5 were assessed, and the delineation of @entity5 margins with each sequence or combination of sequences was evaluated by use of a grading system ranging from 1 (poor) to 3 (excellent). Three @entity1 were excluded because of artifacts on the MR images caused by dental restorations. RESULTS: Tumors in all 41 @entity1 were depicted on unenhanced T1-weighted SE images, but in four @entity1 , @entity5 were not visible on T2-weighted @entity9468 images. Except for @entity5 that invaded the maxillary gingiva, the @entity5 generally had homogeneous, low signal intensity on unenhanced T1-weighted images and nonhomogeneous, high signal intensity on T2-weighted @entity9468 images. All @entity5 showed enhancement, 76% with a nonhomogeneous appearance. The delineation of @entity5 margins was excellent (grade 3) in 31 cases and fair (grade 2) in 10 cases. The highest rating was given for unenhanced T1-weighted images in 10 cases, for contrast-enhanced T1-weighted images in 10 cases, for the combination of both unenhanced and contrast-enhanced T1-weighted images in 18 cases, for the combination of unenhanced T1-weighted and T2-weighted @entity9468 images in five cases, and for T2-weighted @entity9468 images in one case. In three cases, the highest rating was given for both combinations of pulse sequences. CONCLUSION: An unenhanced T1-weighted sequence should be used as the basic pulse sequence for MR imaging of @entity5 of the oral cavity. When @entity5 margins are not clearly delineated with this sequence, T2-weighted @entity9468 and contrast-enhanced T1-weighted sequences should be added. Although both of these sequences provide supplementary information, the contrast-enhanced T1-weighted sequence is more useful in delineating the margins and extent of @entity5 than is the T2-weighted @entity9468 sequence.
