Contrast enhancement of pathologic lymph nodes demonstrated by computed tomography

Area of Science:

• Radiology
• Medical Imaging
• Oncology

Background:

• Enlarged lymph nodes in the mediastinum, retroperitoneum, and pelvis can be challenging to distinguish from vascular structures.
• Contrast medium is crucial in computed tomography (CT) for differentiating lymph nodes from arteries and veins.

Purpose of the Study:

• To investigate the degree of contrast enhancement in pathologic lymph nodes following intravenous contrast medium injection.
• To assess the potential for misinterpretation of enhanced lymph nodes as vascular structures.

Main Methods:

• Computed tomography (CT) was performed on 25 patients with enlarged retroperitoneal lymph nodes.
• Dynamic CT sequences were obtained over two minutes after intravenous bolus injection of contrast medium.
• Contrast enhancement of lymph nodes was correlated with enhancement of the inferior vena cava.

Main Results:

• All examined lymph nodes demonstrated contrast enhancement, with varying degrees observed.
• Most lymph nodes exhibited slight to moderate enhancement.
• Five patients showed strong lymph node enhancement (>75% of inferior vena cava enhancement), raising concerns for potential misinterpretation as blood vessels.

Conclusions:

• Contrast-enhanced CT is valuable for differentiating lymph nodes from vascular structures.
• A subset of pathologic lymph nodes can exhibit significant enhancement, potentially leading to misdiagnosis.
• Radiologists must be aware of the varying enhancement patterns of lymph nodes to avoid misinterpretation.