![]() The main roles of imaging are (1) to confirm the N0 status of the neck, (2) to document lymphadenopathy contralateral to clinically palpable disease, (3) to assess the regional extent of disease especially in relation to neurovascular structures, and (4) nodal surveillance for follow-up. It should also be noted that 50% of nodes harbouring malignant cells measure less than 5 mm and 25% of nodes with extracapsular spread are less than 10 mm. Imaging is not very sensitive and approximately 45% of all histologically verified nodes with extracapsular spread are not seen on CT. Extracapsular spread is diagnosed when the nodes appear matted or the nodal outline appears streaky. The presence of cellulitis helps to separate metastasis from inflammation.Įxtracapsular spread is common with approximately 60% of all metastatic nodes showing extracapsular spread. Suppurative lymphadenitis is usually evident clinically and radiologically. These nodes usually have irregular and ill-defined margins indicating the presence of inflammation. Secondly, suppurative nodes frequently show central areas of low attenuation indicating the formation of pus. The location of the low attenuation focus is of help as necrosis is generally situated centrally while fat is usually deposited around the hilum. Density measurements are of limited value in small lesions because of partial volume averaging. Firstly, fat deposition may produce a low attenuation focus in the suspected node on computed tomography (CT). Nodal necrosis may be confused in two conditions. ![]() The detection of nodal necrosis is therefore most useful if the necrotic nodes are less than 10 mm and there are no other abnormal nodes. In general, the frequency of nodal necrosis increases with nodal size. These nodes are already by size criterion considered as nodes affected by metastasis ( Fig. This is because most nodes with nodal necrosis are larger than 10 mm. Although this sign is highly specific for metastatic disease it is of limited usefulness in clinical practice. The presence of nodal necrosis, irrespective of size, indicates metastatic involvement. On the other hand, 23% of nodes that show extracapsular spread measure less than 10 mm. However, 20% of nodes that exceed 10 mm harbour no metastatic deposits and histologically show only hyperplasia. Nodes larger than 10 mm are conventionally considered abnormal. ![]() Group VI nodes are anteriorly located: between the hyoid bone superiorly, the suprasternal notch inferiorly and between the carotid sheaths laterally ( Fig. Group V nodes can be identified on axial images posterior to the posterior margin of the sternocleidomastoid muscle. Group V nodes are found in the posterior triangle ( Fig. 4), and Group IV nodes are located below the cricoid cartilage ( Fig. 3), Group III nodes are found between the hyoid bone and cricoid cartilage ( Fig. ![]() Hence, Group II nodes are located above the hyoid cartilage ( Fig. ![]() Groups II, III and IV are internal jugular (deep cervical) nodes and they are divided into these three groups by two landmarks: the hyoid bone and the inferior border of the cricoid cartilage. Group IB (submandibular) nodes are found in the submandibular space, around the submandibular gland ( Fig. In practical terms, the Group IA (submental) nodes are located in the submental space, between the anterior bellies of the digastric muscles ( Fig. ![]()
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