Send to

Choose Destination
AJR Am J Roentgenol. 2012 Oct;199(4):777-80.

Can low-dose unenhanced chest CT be used for follow-up of lung nodules?

Author information

Department of Radiology, University Medical Centre Utrecht, HP E.01.132, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.



The purpose of this study is to establish the difference in lung nodule volume between standard-dose contrast-enhanced and low-dose unenhanced CT.


Twenty patients with known pulmonary metastases underwent three CT examinations on 1 day: two unenhanced low-dose (120 kVp and 30 mAs) and a standard-dose (120-140 kVp and 75-200 mAs) contrast-enhanced chest CT examinations. For nodules<1000 mm3, nodule volume was quantified using dedicated software from the CT manufacturer. Wilcoxon's signed rank tests were used for analysis of nodules≤200 mm3 and >200 mm3 (approximately diameter of 8 mm).


One hundred one nodules (n=69≤200 mm3) were analyzed in 15 of these subjects. Measured volume of nodules≤200 mm3 was systematically lower on both low-dose unenhanced CT examinations when compared with standard-dose contrast-enhanced CT (differences, 13.7% and 15.5%, respectively; p<0.0001), but nodule volume was not different between low-dose CT (median difference, 1.0%; p=0.10). Nodule volume was not systematically different between the protocols for nodules>200 mm3 (p>0.30).


For lung nodules≤200 mm3 (approximately 8 mm) the measured volume on low-dose unenhanced CT is significantly lower when compared with standard-dose contrast-enhanced CT. This effect is likely due to contrast administration rather than other imaging parameters, which should be taken into account in the follow-up of lung nodules because growth can remain undetected or doubling time underestimated.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Atypon
Loading ...
Support Center