Can virtual non-enhanced CT be used to replace true non-enhanced CT for the detection of palpable cervical lymph nodes? A preliminary study.

PURPOSE

To investigate the potential of virtual non-contrast CT (VNCT) from dual-energy CT to replace true nonenhanced CT (TNCT) for the detection of enlarged cervical lymph nodes.

MATERIALS AND METHODS

Thirty-nine patients with 94 histopathologically proven cervical lymph nodes were imaged with the dual-energy CT technique. VNCT images from the arterial [VNCT-A] and venous phases [VNCT-V] were obtained with the liver VNC application. The mean CT number and signal-to-noise ratio (SNR) were compared. Image quality was evaluated with a score scale of 1-5. Effective dose (ED) was calculated and compared.

RESULTS

Mean CT numbers of cervical lymph nodes were higher on VNCT than on TNCT (P = 0.034). There was no difference in the SNR among three sets of non-enhanced CT images, but the CNR of VNCT images was higher than that of TNCT images (P < 0.001). Image quality of VNCT from two phases was comparable to that of TNCT (P = 0.070). There was no difference in image quality of three sets of non-enhanced CT images (P > 0.05). ED from dual-phase dual-energy CT was lower than that from tri-phase CT scans (P < 0.001).

CONCLUSION

VNCT images from dual-energy CT of the neck had diagnostic image quality; they have the potential to replace TNCT, thus reducing the radiation dose.