Lymphoma is a type of cancer that originates in the white blood cells, specifically lymphocytes, which are part of the body’s immune system. These cells are found throughout the lymphatic system, a network including lymph nodes, the spleen, and bone marrow. When lymphoma develops, it often leads to the enlargement of lymph nodes, and those in the neck are a common site. Imaging tests, such as computed tomography (CT) scans, are frequently used to assess these lymph nodes.
Why a CT Scan for Neck Lymph Nodes?
A CT scan of the neck lymph nodes is a diagnostic tool used for lymphoma assessment, offering detailed cross-sectional images. This imaging technique helps identify enlarged or abnormal lymph nodes, which can be a sign of the disease. CT scans can detect enlarged lymph nodes or organs and abnormalities in various regions, including the head and neck.
The scan plays a role in the initial diagnosis by revealing suspicious nodes and is also used for staging, determining the disease’s extent. It can also help monitor treatment response. Lymphoma can affect lymph nodes, the spleen, and other organs, and approximately 33% of non-Hodgkin lymphomas are found within the head and neck. CT scans are effective for early detection, with a sensitivity of 77% for detecting cervical lymph node metastasis.
CT scans provide detailed images of both soft tissues and blood vessels, which aids in distinguishing healthy tissue from abnormal lymph nodes. They are fast, non-invasive, and can offer a comprehensive view when multiple areas need evaluation, making them a common imaging method for identifying enlarged or abnormal lymph nodes. While CT scans are useful for identifying suspicious areas, a biopsy remains the definitive way to diagnose lymphoma.
Preparing For and Undergoing the Scan
Preparing for a CT scan of the neck lymph nodes involves specific instructions for clear images. Patients may be advised not to eat or drink for 2 to 4 hours before the scheduled exam, though they can usually take their regular medications with a small sip of water. Inform medical staff about any allergies, especially to iodine-based contrast materials, or existing conditions like kidney issues, as these can affect contrast use. Individuals with diabetes who take Metformin may receive specific instructions if intravenous contrast is used.
During the procedure, the patient lies on a movable table that slides into the CT scanner, shaped like a large ring or box. Remaining still is important during the scan, as movement can blur images and necessitate repeat scans. The examination typically takes about 10 to 15 minutes, including preparation and scanning time.
Contrast material, either oral or intravenous, is frequently used to enhance the visibility of blood vessels and tissues, making lymph nodes and other structures clearer. If intravenous contrast is administered through a needle in the arm, patients might experience a warm sensation throughout their body and a metallic taste in their mouth, which are temporary. After the scan, if contrast was used, drinking plenty of fluids, such as 50-60 ounces of water within 24 hours, is recommended to help flush the contrast.
What the Scan Reveals
Radiologists examine CT scans of the neck lymph nodes for characteristics suggesting lymphoma. One primary indicator is lymph node size; an enlargement, often exceeding 1.5 centimeters in the shortest diameter, can raise suspicion. The shape is also assessed; a loss of the typical oval shape, becoming more rounded, can indicate abnormality.
The internal structure and density of the lymph nodes are also scrutinized. Lymphoma can cause the lymph nodes to appear heterogeneous, meaning they have an uneven texture, or show signs of necrosis (dead tissue). Necrosis, an ill-defined margin, and heterogeneous enhancement of enlarged lymph nodes in the neck are relatively common CT features of peripheral T-cell lymphoma (PTCL), a type of non-Hodgkin lymphoma. Clustering of lymph nodes can also be a significant finding.
While a CT scan can identify these suspicious characteristics, it cannot definitively diagnose lymphoma. These findings are interpreted by a radiologist, who compiles a detailed report for the referring physician. Suspicious findings on a CT scan often necessitate further investigation to confirm a diagnosis.
Next Steps After the Scan
Following a CT scan of the neck lymph nodes, the radiologist sends a report to the referring doctor, usually within two weeks. The doctor reviews these findings with the patient, clarifying what the scan revealed and outlining the next steps.
Outcomes range from normal findings, indicating no suspicious lymph nodes, to suspicious findings requiring further investigation. If the scan shows findings consistent with known lymphoma, the next steps involve planning the appropriate treatment strategy. For suspicious findings, a common next step is a biopsy of the affected lymph node, which is the definitive diagnostic tool.
Additional imaging tests may also be recommended. A positron emission tomography (PET) scan, often combined with a CT scan (PET/CT), is frequently used for more comprehensive lymphoma staging. It can detect cancer cells throughout the body, providing a clearer picture of affected areas. The overall treatment plan depends on the type and stage of lymphoma, as well as the patient’s general health.