Necrosis in metastatic neck nodes: diagnostic accuracy of CT, MR imaging, and US
Ann D King1, Gary M K Tse, Anil T Ahuja
1Department of Diagnostic Radiology and Organ Imaging, Faculty of Medicine, Chinese University of Hong Kong, Prince of Wales Hospital, Ngan Shing St, Shatin, New Territories, Hong Kong SAR, China. b834756@mailserv.cuhk.hk
Purpose:
To compare the diagnostic accuracy of computed tomography (CT), magnetic resonance (MR) imaging, and ultrasonography (US) in the detection of necrosis in metastatic cervical nodes from patients with head and neck squamous cell carcinoma.
Materials And Methods:
Twenty-seven patients (age range, 39-85 years; mean age, 62 years) with squamous cell carcinoma in the head and neck underwent CT, MR imaging, and US. Three radiologists evaluated the images for nodal necrosis. The results of each modality were analyzed for sensitivity, specificity, and accuracy. Pathologic analysis of the surgical resection served as the reference standard. The three modalities were compared for specificity and sensitivity with the McNemar test.
Results:
Pathologic examination revealed 903 nodes, of which 89 were malignant. Of the malignant nodes, 43 were necrotic. Analysis of the detection of necrosis in the 89 malignant nodes showed an accuracy, sensitivity, and specificity of 92%, 91%, and 93% for CT; 91%, 93%, and 89% for MR imaging; and 85%, 77%, and 93% for US, respectively. All imaging modalities failed to depict necrotic areas of 3 mm or smaller in three nodes, and necrosis was missed in an additional seven nodes with US and in one node with CT. Necrosis could not be distinguished from other components of malignancy, such as viable tumor and scar tissue, in seven nodes (CT, 3; MR imaging, 5; US, 3). The sensitivity of both MR imaging and CT was significantly better than that of US (P =.0082 and P =.0339, respectively). There was no significant difference in sensitivity (P =.3173) between MR imaging and CT, or in the specificity of the three modalities.
Conclusion:
MR imaging is comparable to CT for the detection of necrosis. The sensitivity of MR imaging and CT is better than that of US.
