Power doppler sonography of normal and abnormal cervical lymph nodes

Abstract

Power Doppler sonography was performed twice in 20 healthy Chinese subjects to evaluate the repeatability of measurement of size, blood flow velocity (peak systolic velocity, PSV and end diastolic velocity, EDV) and vascular resistance (resistive index, RI and pulsatility index, PI) of cervical nodes. Seventy power Doppler sonograms were reviewed to evaluate the repeatability of assessment of vascular pattern, degree of vascularity and displacement of vessels of cervical lymphadenopathy. A total of 139 normal cervical nodes were detected in the first scan and they were re-scanned in the second scan. One node was detected in the second scan but not in the first scan. Fifty cervical nodes showed arterial flow in both scans, and blood flow velocity and vascularity resistance were measured. The mean value of PSV, EDV, RI and PI had a higher repeatability than their highest and lowest values. There was a high repeatability in the measurement of maximum transverse diameter (97%), mean PSV (95%), mean EDV (96%), mean RI (86%) and mean PI (87%). The repeatability in evaluation of vascular pattern (85%), degree of vascularity (95%) and displacement of vessels (88%) were also high. One hundred and thirty-six healthy Chinese subjects were given an ultrasound examination of the neck. A total of 1377 normal cervical lymph nodes were detected and examined with power Doppler sonography. Detectable lymph nodes were usually found in the submandibular, parotid, upper cervical, and posterior triangle regions. Normal cervical lymph nodes tended to show central vascularity or appeared avascular, and thus the presence of peripheral vascularity was likely to indicate pathology. The detection of vascular signals within normal cervical nodes varied with the regions of the neck, age and nodal size, but not with gender. Normal cervical nodes tended to have grade 1 vascularity. The degree of vascularity and blood flow velocity of normal cervical nodes varied with regions of the neck and nodal size, but not with age and gender. The vascular resistance varied with regions of the neck, age and nodal size, but not with gender. In the investigation of racial difference in the vasculature of cervical nodes between Chinese and Caucasians, 20 healthy Caucasians subjects had an ultrasound examination of the neck, the results of which were compared with 20 age- and gender- matched healthy Chinese subjects. Lymph nodes were evaluated for their number, size, site, echogenic hilus, vascular pattern, degree of vascularity, blood flow velocity and vascular resistance. There was no significant difference in the grey scale and vascular features of cervical nodes between Caucasians and Chinese. Two hundred and eighty-six patients with palpable neck nodes were given an ultrasound examination of the neck. Patients were classified into eight categories. In each patient, power Doppler sonography and fine-needle aspiration cytology were performed on the largest node, which was included in the study. Lymph nodes with peripheral vascularity were highly suggestive to be pathologic. Displaced central vascularity was common in tuberculous nodes. Vascular pattern was more accurate than other criteria in differentiating malignant nodes from normal and reactive nodes. Vascular resistance is useful to distinguish between different causes of malignant cervical nodes. Displacement of vascularity was helpful to differentiate tuberculous nodes from normal, reactive and malignant nodes. Peak systolic velocity (PSV) was more accurate in differentiating reactive from normal nodes. The value which power Doppler sonography added to the routine grey scale sonography was also investigated. Grey scale sonography provided high accuracy in identifying metastatic (88-100%), lymphomatous (86%), tuberculous (93%), reactive (90%) and normal (98%) nodes. The addition of power Doppler sonography improved the accuracy (metastases, 100%; lymphoma, 95%; tuberculosis, 96%; reactive, 100%; normal, 100%). Results suggest that power Doppler sonography is not indicated for every case in routine practice, but should be used for those cases where grey scale sonography is equivocal.