Objective:

To analyze the application value of low dose and ultra-low dose chest CT scans in re-examination of pulmonary nodules with different types.

Methods:

A total of 100 patients with non-calcified solitary pulmonary nodules (5-30 mm) found by routine dose chest CT scan were chosen. Then low dose (50 mA) and ultra-low dose (25 mA) chest CT scans were used for re-examination. The results of the two CT scans were compared.

Relative volume difference (RVD) was obtained on SIEMENS Syngo MMWP VE40A workstation. RVD less than or equal to 10% was considered reasonable. RVD more than 10% was considered unreasonable.

Results:

The reasonable rate of two volume measurements was 78.00%. The correlation coefficient r was 0.996

and there was no significant difference between the two volume measurements. The 95% confidence interval (CI) of RVD was -0.14-0.14. The overall RVD tended to be consistent. The unreasonable rate of RVD in para pleural nodules and burr nodules was significantly higher than that in other type nodules.

Conclusion:

Low dose of 50 mA and ultra-low dose of 25 mA chest CT scans were similar in RVD measurement. Ultra-low dose of 25 mA chest CT scan is suitable for burr nodules and para pleural nodules.