Magnetic resonance imaging and computed tomography in pediatric head and neck masses. Fifty-three magnetic resonance imaging (MRI) and 25 computed tomography (CT) studies of 53 head and neck masses in pediatric patients were reviewed retrospectively. All lesions had pathologic proof except for 2 metastatic and 2 recurrent lesions, which only had prior pathologic confirmation at their primary sites. These included 12 malignant tumors, 23 benign tumors, 6 inflammatory masses, and 12 congenital lesions. The MRI performance ranged predominantly from good to excellent in detection of the lesion and the extent of involvement and in contrast to the surrounding tissue; when CT comparison was available, MRI proved to be equal to or better than it in detection of these factors and in preoperative diagnosis. Our results suggest that MRI should be the method of choice for the initial evaluation of the pediatric head and neck region, especially in those patients requiring multiple examinations. However, CT and MRI should be used conjunctively in complicated cases, especially those possibly involving lesions with calcifications or bony involvement. 