Dose Reduction for Semi-Automated Volumetry of Hepatic Metastasis in MDCT Studies

作者:Keil Sebastian*; Plumhans Cedric; Nagy Istvan A; Schiffl Katharina; Soza Grzegorz; Behrendt Florian F; Mahnken Andreas H; Guenther Rolf W; Das Marco
来源:Investigative Radiology, 2010, 45(2): 77-81.

摘要

Objectives: To investigate the performance of semi-automated measurements (RECIST, volume) of hepatic metastases in multidetector-row computed tomography (MDCT) under normal-dose- and simulated low-dose-protocols.
Materials and Methods: Thirty-five patients (67 +/- 13 years) with a total of 79 hepatic metastases underwent 16-MDCT (120 kv, 160 mAs(eff), pitch 1, 3 mm slice thickness, 2 mm reconstruction increment, B30f standard soft tissue kernel) for either initial staging or therapy monitoring. Corresponding raw data from these standard-dose scans were simulated at lower radiation doses of 80/60/40 mAs(eff) (Somatom Noise Vers.6.1 beta, Siemens Healthcare, Forchheim, Germany). A semi-automated software tool (SyngoCT Oncology, Siemens Healthcare, Forchheim, Germany) was applied to each dose setting to evaluate size parameters (RECIST, volume). These measurements were compared by applying repeated-measures analysis of variance and displayed graphically.
Results: For RECIST measurements no statistically significant differences were found between standard dose (Mean RECIST diameter: 20.46 +/- 8.37 mm) and different simulated low radiation doses (80 mAs(eff): 20.95 +/- 8.20 mm/60 mAs(eff). 20.50 +/- 8.35 mm/40 mAs(eff). 19.95 +/- 8.16 mm): P = 0.0774.
Statistically significant differences of volume quantification (P < 0.05) could be found between standard-(3.60 +/- 4.63 mL) and simulated lowest dose of 40 mAs(eff) (3.17 +/- 4.08 mL), whereas there was no difference (P > 0.05) between 160 mAs(eff)- and either 80 mAs(eff)-(3.46 +/- 4.31 mL) or 60 mAs(eff)-protocols (3.44 +/- 4.35 mL).
Conclusions: Software-assisted assessment of RECIST criteria and volume demonstrated valid performances under different dose-settings in MDCT; therefore, substantial radiation dose reduction could be possible with the use of semi-automated measurements in follow-up studies.