Hisanobu Koyama MD, PhD, Presenter: Nothing to Disclose

Yoshiharu Ohno MD, PhD, Abstract Co-Author: Research Grant, Toshiba Corporation Research Grant, Koninklijke Philips NV Research Grant, Bayer AG Research Grant, DAIICHI SANKYO Group Research Grant, Eisai Co, Ltd Research Grant, Terumo Corporation Research Grant, Fuji Yakuhin Co, Ltd Research Grant, FUJIFILM Holdings Corporation Research Grant, Guerbet SA

Shinichiro Seki, Abstract Co-Author: Nothing to Disclose

Mizuho Nishio MD, PhD, Abstract Co-Author: Research Grant, Toshiba Corporation

Takeshi Yoshikawa MD, Abstract Co-Author: Research Grant, Toshiba Corporation

Sumiaki Matsumoto MD, PhD, Abstract Co-Author: Research Grant, Toshiba Corporation

Masao Yui, Abstract Co-Author: Employee, Toshiba Corporation

Hitoshi Yamagata PhD, Abstract Co-Author: Employee, Toshiba Corporation

Yu Ueda PhD, Abstract Co-Author: Nothing to Disclose

Katsusuke Kyotani RT, Abstract Co-Author: Nothing to Disclose

Kazuhiro Kubo RT, Abstract Co-Author: Nothing to Disclose

Kazuro Sugimura MD, PhD, Abstract Co-Author: Research Grant, Toshiba Corporation Research Grant, Koninklijke Philips NV Research Grant, Bayer AG Research Grant, Eisai Co, Ltd Research Grant, DAIICHI SANKYO Group

Computed diffusion-weighted imaging (cDWI) is the newly proposed method to generate DWI with arbitrary b-values from acquired DWIs (aDWIs) with different b values. The purpose of this study is to directly and prospectively compare capabilities for pulmonary nodule/mass detection and differentiation of malignant from benign lesions among cDWI and aDWIs.

Ninety-seven patients (64 men and 33 women, mean age 69.1 years) with 121 pulmonary nodules/masses (mean diameter; 28.9mm, median; 24mm) underwent DWI with b values at 0, 500 and 1000 s/mm2 by 1.5 T MR system. According to pathological and/or follow up examinations, these pulmonary lesions were divided into malignancy (n=97) and benign (n=24). Then, cDWI with b value at 1,000 s/mm2 (cDWI1000) were computationally generated from aDWIs with b-values at 0 and 500 s/mm2 by our propriety software. To evaluate detection capability of DWI, aDWIs with b values at 500 s/mm2 (aDWI500) and 1,000 s/mm2 (aDWI1000) and cDWI1000 were visually assessed by means of 5-points scoring system. For quantitative diagnosis of pulmonary lesion, lesion to spinal cord ratio (LSR) on each DWI was calculated. To evaluate the detection capability, detection rate was compared among aDWI500, aDWI1000 and cDWI1000 by McNemar's test. To determine the feasible threshold value for differentiation, ROC-based positive test was performed, and differentiation capability was compared by sensitivities (SE) and accuracies (AC) among aDWI500 with and without cDWI1000, aDWI1000, and cDWI1000 by McNemar's test.

The detection rate of aDWI500 (99.2%) was significantly higher than that of aDWI1000 (92.6%, p<0.05), however no significant difference with that of cDWI1000 (96.7%, p>0.05). There was no significant difference among aDWI500 without cDWI1000 (SE; 72.6%, and AC; 70.3%), aDWI1000 (SE; 73.2%, and AC; 71.9%) and cDWI1000 (SE; 78.5%, and AC; 75.2%). However, the SE and AC of aDWI500 with cDWI1000 (SE; 80.4%, and AC; 76.9%) were significantly higher than those of aDWI500 without cDWI1000 and aDWI1000 (p<0.05).

Computed DWI was useful technique, and the combination of aDWI500 with cDWI1000 would be better to choose in clinical practice for the evaluation of pulmonary nodules/masses.

Computed DWI with high b value added to really acquired DWI with a relatively low b value improves the diagnostic capabilities for the evaluation of pulmonary nodule/mass.

Koyama, H, Ohno, Y, Seki, S, Nishio, M, Yoshikawa, T, Matsumoto, S, Yui, M, Yamagata, H, Ueda, Y, Kyotani, K, Kubo, K, Sugimura, K, Computed Diffusion-weighted Imaging with High b-Value: How to Apply for Improving Pulmonary Nodule/Mass Assessment Capability with Acquired Diffusion-weighted Imaging.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14001642.html