Computed tomography image characteristics of metastatic lymph nodes in patients with squamous cell carcinoma of the head and neck.

OBJECTIVE

Metastatic neck nodes are commonly described as "heterogenous" or "inhomogenous" on computed tomographic (CT) images, and this remains a highly subjective issue. The purpose of this study is to justify classical criteria and to develop novel supplemental methods for diagnosing a positive neck node on CT scans.

METHODS

Fifty-four patients with H&N SCC were separated into two groups according to their neck nodal status. CT scan digital images were used and the lymph node borders were selected by a radiologist. Lymph node images from the pathologically proven N- (negative for cervical metastases) group were compared to the N+ (positive for cervical metastases) group. Image-analysis software, ImageJ, was used to record and compare various characteristics collected from the images.

RESULTS

The image-analysis comparisons shows, the area (size) of the lymph node in the N+ group is much larger than the N- group (474.02 VS.81.55mm(2)) (P<0.01). There are no significant differences with regards to distribution of pixel values between the two groups (P=0.79). The lacunarity, a parameter used to describe gappiness or inhomogeneity, of the N+ group was significantly higher than the N- group (P=0.026).

CONCLUSIONS

While size of the lymph node remains an important factor in the interpretation of a clinically suspicious lymph node metastasis on CT scan images, the distribution of pixel values could not clarify a heterogeneous state. Nevertheless, 'lacunarity' proves to be a more accurate parameter which correlates better to the subjective heterogeneity.