Yukihiro Nagatani MD, Presenter: Nothing to Disclose

Masashi Takahashi MD, Abstract Co-Author: Nothing to Disclose

Kiyoshi Murata MD, Abstract Co-Author: Nothing to Disclose

Mitsuru Ikeda MD, Abstract Co-Author: Nothing to Disclose

Tsuneo Yamashiro MD, Abstract Co-Author: Nothing to Disclose

Tetsuhiro Miyara, Abstract Co-Author: Nothing to Disclose

Hisanobu Koyama MD, Abstract Co-Author: Nothing to Disclose

Mitsuhiro Koyama MD, Abstract Co-Author: Nothing to Disclose

Yukihisa Satoh, Abstract Co-Author: Nothing to Disclose

To compare lung nodule detectability (LND) on computed tomography (CT) with adaptive iterative dose reduction using three dimensional processing (AIDR3D) between ultra-low dose CT scanning (ULDS) and low dose CT scanning (LDS)

This was part of the Area-detector Computed Tomography for the Investigation of Thoracic Diseases (ACTIve) Study, a multicenter research project being conducted in Japan. The Institutional Review Board of each institution approved this study and written informed consent was obtained. In a single visit each, 83 subjects underwent chest CT (64-row helical mode) using identical multi-detector CT scanners at a gantry rotation speed of 0.35 second with three different tube currents: 240,120 and 20 mA (2.51, 1.26 and 0.21mSv, respectively). Axial CT images with 2-mm thickness and increment were reconstructed using AIDR3D. Standard of reference (SOR) was determined on the basis of CT images at 240mA by consensus reading of two board-certificated radiologists with regard to the presence of nodule with the longest diameter of more than 3mm. Five radiologists independently assessed and recorded presence/absence of lung nodules and their locations by continuously-distributed rating in CT images at 20mA (ULDS) and 120mA (LDS). Receiver-operating characteristic (ROC) analysis by jackknife method was used to evaluate LND of both methods in total and also in subgroups classified by nodular longest diameter (>4, 6 and 8mm) and characteristics (solid and non-solid).

For SOR, 160 solid and 61 non-solid lung nodules were totally identified. No significant difference in LND for nodules with the longest diameter of more than 6mm was shown between both methods, as area under ROC curve was 0.932±0.020 in ULDS and 0.948±0.020 in LDS. Similarly, for the entire solid nodules, LND was quite similar between both methods, as area under ROC curve was 0.844±0.017 in ULDS and 0.876±0.026 in LDS.

It was demonstrated that ULDS with AIDR3D could have comparable LND to LDS with AIDR3D except for smaller non-solid nodules.

ULDS with AIDR3D has a sufficient potential to be used for lung cancer screening.

Nagatani, Y, Takahashi, M, Murata, K, Ikeda, M, Yamashiro, T, Miyara, T, Koyama, H, Koyama, M, Satoh, Y, Lung Nodule Detectability on Computed Tomography at Ultra-low Dose Scanning with Adaptive Iterative Dose Reduction Using Three Dimensional Processing (AIDR3D): Comparison with Low-dose Scanning by Receiver-operating Characteristic Analysis.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13022648.html