Can B-ultrasound be used to distinguish benign and malignant lymph nodes?

Although people's living standards are getting better and better, there have always been great hidden dangers due to food safety. Nowadays, with the rise of many fast foods and instant foods, more and more people are suffering from tumors. Among them, lymphoma is a common tumor, which can be benign or malignant. It is generally difficult to distinguish between benign and malignant lymph nodes through B-ultrasound, and further biopsy is needed to distinguish them.

Diagnosis of benign and malignant lymph nodes:

1. Superficial lymph nodes refer to the lymph nodes located in the deep fascia layer of the body surface and within 3.0 cm from the skin. Lymphadenopathy is often a reflection of both local and systemic disease. Superficial lymph nodes (head and neck, axilla, supraclavicular fossa and inguinal area) are an important basis for diagnosing and staging malignant tumors, formulating treatment plans and analyzing therapeutic effects. Anatomically, lymph nodes are oval in shape, with a minimum long diameter of 0.1 cm and a maximum long diameter of 2.5 cm. They are divided into capsule, cortex, and medulla.

2. The internal echoes of benign enlarged lymph nodes often show widening and enhancement of the medulla and relative narrowing of the cortex, while the internal echoes of malignant enlarged lymph nodes are the opposite. CDFI shows that the blood flow in benign enlarged lymph nodes is abundant and regular, mostly in a tree-like distribution; while the blood flow in malignant enlarged lymph nodes mostly presents irregular and chaotic blood flow signals.

3. Previous research results suggest that lymph nodes with a longitudinal diameter >8mm, a transverse diameter >5mm, and a L/S ratio <2 are mostly malignant lymph nodes. Single long diameter measurement should not be used as a diagnostic criterion for abnormal lymph nodes. Under pathological conditions, the changes in the transverse diameter of lymph nodes are more obvious than the longitudinal diameter. It is more reasonable to use the longitudinal diameter/transverse diameter value.

CDFI in benign lymph nodes shows that the blood flow is regular and evenly distributed, mostly in the shape of waterweed and regular branches, and is proportional to the degree of swelling. In terms of spectrum morphology, benign lesions are of low resistance type, with steep straight waves, sharp S1 peaks, and wide waveforms.

4. The blood flow distribution of malignant lymph nodes is divided into the following four types: (1) intranodal avascular type; (2) intranodal vascular mobile type; (3) central vascular disorder type; (4) peripheral vascular type. The spectrum is high resistance type, with a single peak wave, rounded S1 peak and prolonged peak time. Irregular dendritic and chaotic lymph node blood flow patterns and RI>0.70 are indicators for diagnosing malignant lymph nodes.

Lymph node enlargement is a common manifestation of many diseases. Any antigen stimulation can cause the lymph nodes to respond. Color Doppler ultrasound is used to observe the morphology, L/S value, internal echo, CDFI performance and PWD index of the diseased lymph nodes. Combining the medical history and physical signs is of great significance for distinguishing between benign and malignant lymph nodes. It has important reference value for clinical diagnosis, but there is still a certain amount of overlap. Therefore, ultrasound-guided puncture biopsy is more helpful for the differential diagnosis of benign and malignant enlarged lymph nodes.