Improved Diagnostic Accuracy Using Arterial Phase CT for Lateral Cervical Lymph Node Metastasis from Papillary...

Area of Science:

• Radiology
• Oncology
• Medical Imaging

Background:

• Contrast-enhanced CT protocols for papillary thyroid cancer require optimization.
• Accurate detection of lateral cervical lymph node metastasis is vital for patient management.

Purpose of the Study:

• To compare the diagnostic accuracy of different contrast-enhanced CT protocols for identifying lateral cervical lymph node metastasis in papillary thyroid carcinoma.
• To evaluate the role of lymph node tissue attenuation in differentiating metastatic from benign lymph nodes.

Main Methods:

• Retrospective analysis of 327 lateral cervical lymph nodes from 131 patients with papillary thyroid carcinoma.
• Comparison of three CT protocols: 70-sec delay/100 mL contrast (A), 35-sec delay/100 mL contrast (B), and 25-sec delay/75 mL contrast (C).
• Independent measurement of lymph node tissue attenuation by two readers, followed by ROC curve analysis.

Main Results:

• Protocol C demonstrated the highest diagnostic performance (AUC 0.88-0.92), significantly outperforming protocols A (AUC 0.73-0.74) and B (AUC 0.63-0.65).
• Mean lymph node tissue attenuation difference was maximal in protocol C (P < .001).
• Sensitivity and specificity for metastasis detection using protocol C were high (83%-97.9%).

Conclusions:

• A CT protocol combining a 25-second delay with 75 mL of iodinated IV contrast significantly improves diagnostic accuracy for lateral lymph node metastasis in papillary thyroid carcinoma.
• This optimized protocol is superior to those using longer delays (35- or 70-seconds) with higher contrast volume (100 mL).