Tsutomu Gomi PhD, Presenter: Nothing to Disclose

Masahiro Nakajima BSC, Abstract Co-Author: Nothing to Disclose

Hiroki Fujiwara MD, Abstract Co-Author: Nothing to Disclose

Tokuo Umeda PhD, Abstract Co-Author: Nothing to Disclose

Akiko Okawa RN, PhD, Abstract Co-Author: Nothing to Disclose

Tohoru Takeda MD, PhD, Abstract Co-Author: Nothing to Disclose

Kazuya Sakaguchi, Abstract Co-Author: Nothing to Disclose

To compare the effectiveness of chest dual-energy subtraction digital tomosynthesis (DES-DT) and dual-energy subtraction radiography (DES-R) to detect simulated pulmonary nodules with and without superimposed calcifications.

DES-DT and DES-R systems (SonialVision Safire II, Shimadzu Co., Kyoto, Japan) with pulsed X-rays and rapid kV switching were used to examine simulated pulmonary nodules (5 mmφ and 7 mmφ, ground glass opacity) with and without calcifications (using hydroxyapatite). The simulated nodules were arranged in the lung region and superimposed over the heart. Low-voltage (60 kVp), high-voltage (120 kVp), and soft-tissue or bone-subtracted tomograms of the desired layer thicknesses were reconstructed from image data acquired during a single tomographic scan using a 3D filtered back-projection algorithm and scan angle of 40°. DES-R images were processed from low- and high-voltage images. We took into account the signal-to-noise ratio (SNR) of the simulated nodules with and without calcifications. To detect the nodules and calcification, we examined 50 samples with and 50 samples without simulated nodules using both systems. Five thoracic radiologists conducted a receiver operating characteristic (ROC) study to evaluate the results.

SNR and quality of DES-DT images were significantly superior to those obtained by DES-R. For DES-DT, SNR for the 5 mmφ nodules was 31% (without calcification) and 39% (with calcification); this increased with size to a SNR for the 7 mmφ nodules of 59% (without calcification) and 75% (with calcification). Based on the results of ROC analysis, the detection ability of our DES-DT was significantly better than that of DES-R (P < .01). When the calcifications were no longer superimposed over the nodules, their characteristics and distribution in the simulated nodules could be clearly observed.

DES-DT proved better than DES-R providing greater sensitivity than DES-R to detect simulated nodules with and without calcifications, especially when large nodules were analyzed.

We believe that DES-DT imaging quality can facilitate detection of pulmonary nodules with and without calcifications.

Gomi, T, Nakajima, M, Fujiwara, H, Umeda, T, Okawa, A, Takeda, T, Sakaguchi, K, Comparison of Chest Dual Energy Subtraction Digital Tomosynthesis and Dual Energy Subtraction Radiography to Detect Simulated Pulmonary Nodules with and without Calcifications: Evaluation of Phantom Study.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9000774.html