Evaluation of diffuse lymphadenopathy via various quantitative PET/CT parameters

Area of Science:

• Nuclear Medicine
• Radiology
• Oncology

Background:

• Diffuse lymphadenopathy (DLAP) on ¹⁸F-FDG PET/CT indicates various conditions, from benign to malignant.
• Accurate differential diagnosis is crucial for appropriate clinical management.

Purpose of the Study:

• To evaluate the diagnostic role of metabolic parameters derived from ¹⁸F-FDG PET/CT in DLAP.
• To differentiate between malignant and benign causes of DLAP, and specifically between lymphoma and sarcoidosis.

Main Methods:

• Retrospective review of 78 patients with DLAP who underwent ¹⁸F-FDG PET/CT.
• Measurement of largest lymph node diameter, SUVmax of liver, spleen, and bone marrow.
• Calculation of SUVmax ratios to liver SUVmax (LLRmax, SLRmax, BMLRmax).

Main Results:

• Specific cut-off values for largest lymph node diameter, Llyn.SUVmax, LLRmax, and SLRmax showed moderate to good sensitivity and specificity for risk stratification of malignancy.
• Largest lymph node diameter, SLRmax, and BMLRmax were valuable in differentiating lymphoma from sarcoidosis with high sensitivity and specificity.

Conclusions:

• High Llyn.SUVmax and LLRmax are characteristic of lymphoma, metastasis, and sarcoidosis.
• Largest lymph node diameter, SLRmax, and BMLRmax are key parameters for distinguishing lymphoma from sarcoidosis.
• ¹⁸F-FDG PET/CT patterns provide valuable diagnostic insights for DLAP.