الفهرس 
Gross Anatomy of Lymph NodesOnly 14 pages are availabe for public view
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Abstract
F
ifty cases with palpable lymph nodes (eighteen cases were affected by benign processes, twelve cases nodes were involved by 1ry malignant process and twenty cases were displayed metastatic lymhadenopathy), were evaluated using real time B-mode, color Doppler, and power Doppler sonography and were finally diagnosed by histopathological examination of either fine needle aspirates and excisional biopsy.
There was no significant statistical difference between benign and malignanat nodes regarding sex and age distribution.
• The longitudinal to transverse ratio (L/T ratio) is a valuable criterion for differentiation benign from malignant nodes. There was significant increase in the probability of benignity towards the oval shape (L/T >2) and significant increase in the probability of malignancy towards the rounded shape (L/T < 2) of the affected node.
• There was significant statistical differences between benign and malignant nodes regarding echogenic hilum distribution of the affected nodes. There was significant increase in the probability of benignity when the affected node showed normal (central) echogenic hilum. Also, there was significant increase in the probability of malignancy when the affected node had a deformed or absent hilum.
• There was highly significant agreement regarding distribution of the sites of nodal perfusion. The benign nodes were mainly perfused in the hilum, which represents the natural site for blood vessels to enter the node (central perfusion). In nodal malignancies, perfusion was found in the nodal periphery (peripheral perfusion) or in the periphery as well as in the center of the node (mix perfusion).
• The examined lymph nodes displayed different vascular pattern, which showed high statistical difference between benign and malignant nodes evaluated by power Doppler. The benign nodes were mainly of Type I. vascular pattern (a single vascular pole in the hilum with a small artery entering the node) On the other hand, the malignant nodes showed Type II vascular pattern (Hypertrophic single hilar vascular pole which is the main feeding artery and two or more branching arteries in periphery of the node representing mixed pattern) and Type III vascular pattern (mainly peripheral vascularity with three or more vascular branches perforating the capsule peripherally and directed towards the center of the node).
• Associated features such as intra-nodal necrosis, calcifications, matting and cystic changes are more commonly seen in malignant nodes.
• It was found at cut off 0.8 for resistive index (RI), and 1.5 for pulsatility index (PI) is the best sensitive and specific cut off to discriminate malignant from benign lymph nodes.
In every case B-mode ultrasound, color and power Doppler have to be done. B-mode assesses the shape and hilum of the lymph nodes, while color and power Doppler evaluate the intra-nodal vascularity and visualize the Doppler spectral waveforms. However, FNAC and/ or excisional biopsy are needed to confirm the diagnosis.
Accurate diagnostic work up of patients with neoplasms is important, because treatment and prognosis are mainly determined by nodal disease. Therefore, differentiation between benign and malignant nodal disease is important in oncology.
Beside to the role of ultrasound in differentiating between malignant and benign lymph node disease, ultrasound is important in follow up of cases of lymphadenopathy especially the primary malignant lymph node disease.
CT and MRI are associated with several important drawbacks like high costs, limited availability, they need to use intravenous contrast and in case of CT, radiation exposure. Howevere, they have an important role if the primary was unknown and metastatic lymph node disease was suspected by US examination and FNAC or in cases of generalized lymphadenopathy workup.
Furthermore, for the detection of the nodes in the submental and submandibular regions, were CT and MRI studies have occasionally been impaired by artifacts from bones and dental amalgam, the addition of Doppler techniques to the sonographic evaluation facilitated the early detection of metastatic nodes with high rates of sensitivity and specificity. However, in equivocal cases, which were not diagnosed correctly by ultrasound and Doppler examination, MRI study is of value and is recommended in such cases.