Distinction between benign and malignant causes of cervical, axillary, and inguinal lymphadenopathy: value of Doppler spectral waveform analysis.

OBJECTIVE: Vessels in inflamed lymph nodes are dilated compared with vessels in lymph nodes involved with metastases, which may be compressed by tumor cells. Accordingly, we hypothesized that the Doppler spectral waveform might be different in lymph nodes involved by benign disease and those involved by metastases. We compared spectral waveforms of benign and malignant superficial lymphadenopathy to determine the value of color Doppler sonography in distinguishing between the two. SUBJECTS AND METHODS: Palpable superficial lymph nodes (41 cervical, one axillary, one inguinal) of 43 untreated patients were prospectively evaluated with color Doppler sonography. We measured resistive index, pulsatility index, peak systolic velocity, and end diastolic velocity from the fastest or next fastest arterial signal in the lymph node that showed the most vigorous flow. Final diagnosis was established by pathologic examination (n = 24) and clinical follow-up (n = 19).
RESULTS: Color Doppler sonography showed blood flow in all cases. The mean resistive index was 0.92 +/- 0.23 in lymph nodes involved with metastases and 0.59 +/- 0.11 in lymph nodes affected by benign processes. The mean pulsatility index was 2.66 +/- 1.59 in lymph nodes involved with metastases and 0.90 +/- 0.23 in lymph nodes affected by benign processes. Lymph nodes involved with metastases showed a characteristic high resistive index (> 1.0) and a high pulsatility index (> 1.5) in 10 of 13 cases. Lymph nodes affected by benign processes showed a low resistive index (< 0.8) and a low pulsatility index (< 1.5) in all cases. The resistive indexes and pulsatility indexes were significantly different (p < .005) between lymph nodes affected by benign versus malignant disease. The mean peak systolic velocity was 25 +/- 11.7 cm/sec in lymph nodes involved with metastases and 24 +/- 16 cm/sec in lymph nodes affected by benign processes. The mean end diastolic velocity was 2 +/- 6.7 cm/sec in lymph nodes involved with metastases and 10 +/- 9.5 cm/sec in lymph nodes affected by benign processes. Although the peak systolic velocities were not significantly different, the end diastolic velocities were significantly different (p < .005) between the two types of lymph nodes.
CONCLUSION: Our results suggest that superficial lymphadenopathy due to benign and malignant diseases can be distinguished with a high degree of accuracy (p < .005) by means of spectral waveform analysis. Color Doppler sonography is a useful adjunct to routine sonography. Lymph nodes with a high resistive index are almost always involved by metastases.