Tsukasa Yoshida1,2, Atsushi Urikura3, Kensei Shirata3, Yoshihiro Nakaya3, Masahiro Endo3, Shingo Terashima4, Yoichiro Hosokawa4. 1. Department of Diagnostic Radiology, Shizuoka Cancer Center, 1007, Shimonagakubo, Nagaizumi, Sunto, Shizuoka, 411-8777, Japan. ts.yoshida@scchr.jp. 2. Department of Radiation Science, Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, 036-8564, Japan. ts.yoshida@scchr.jp. 3. Department of Diagnostic Radiology, Shizuoka Cancer Center, 1007, Shimonagakubo, Nagaizumi, Sunto, Shizuoka, 411-8777, Japan. 4. Division of Medical Life Sciences, Department of Radiological Life Sciences, Hirosaki University, 66-1 Hon-cho, Hirosaki, 036-8564, Japan.
Abstract
OBJECTIVE: This study aimed to compare the signal-to-noise ratios (SNRs) and apparent diffusion coefficients (ADCs) obtained using two fat suppression techniques in breast diffusion-weighted imaging (DWI) of a phantom. MATERIALS AND METHODS: The breast phantom comprised agar gels with four different concentrations of granulated sugar (samples 1, 2, 3, and 4). DWI with short tau inversion recovery (STIR-DWI) and that with spectral attenuated inversion recovery (SPAIR-DWI) were performed using 3.0-T magnetic resonance imaging, and the obtained SNRs and ADCs were compared. ADCs were also compared between the right and left breast phantoms. RESULTS: For samples 3 and 4, SNRs obtained using STIR-DWI were lower than those obtained using SPAIR-DWI. For samples 2, 3, and 4, overall ADCs obtained using STIR-DWI were significantly higher than those obtained using SPAIR-DWI (p < 0.001 for all), although no significant difference was observed for sample 1 (p = 0.62). STIR-DWI shows a positive bias and wide limits of agreement in Bland-Altman plot. The coefficients of variance of overall ADCs were good in STIR-DWI and SPAIR-DWI. For all samples, STIR-DWI demonstrated slightly larger percentage differences in ADCs between the right and left phantoms than SPAIR-DWI. CONCLUSION: SNRs and ADCs obtained using STIR-DWI are influenced by the T 1 value; a shorter T 1 value decreases SNRs, overestimates ADCs, and induces the measurement error in ADCs. STIR-DWI showed a larger difference in ADCs between the right and left phantoms than SPAIR-DWI.
OBJECTIVE: This study aimed to compare the signal-to-noise ratios (SNRs) and apparent diffusion coefficients (ADCs) obtained using two fat suppression techniques in breast diffusion-weighted imaging (DWI) of a phantom. MATERIALS AND METHODS: The breast phantom comprised agar gels with four different concentrations of granulated sugar (samples 1, 2, 3, and 4). DWI with short tau inversion recovery (STIR-DWI) and that with spectral attenuated inversion recovery (SPAIR-DWI) were performed using 3.0-T magnetic resonance imaging, and the obtained SNRs and ADCs were compared. ADCs were also compared between the right and left breast phantoms. RESULTS: For samples 3 and 4, SNRs obtained using STIR-DWI were lower than those obtained using SPAIR-DWI. For samples 2, 3, and 4, overall ADCs obtained using STIR-DWI were significantly higher than those obtained using SPAIR-DWI (p < 0.001 for all), although no significant difference was observed for sample 1 (p = 0.62). STIR-DWI shows a positive bias and wide limits of agreement in Bland-Altman plot. The coefficients of variance of overall ADCs were good in STIR-DWI and SPAIR-DWI. For all samples, STIR-DWI demonstrated slightly larger percentage differences in ADCs between the right and left phantoms than SPAIR-DWI. CONCLUSION: SNRs and ADCs obtained using STIR-DWI are influenced by the T 1 value; a shorter T 1 value decreases SNRs, overestimates ADCs, and induces the measurement error in ADCs. STIR-DWI showed a larger difference in ADCs between the right and left phantoms than SPAIR-DWI.
Entities:
Keywords:
Apparent diffusion coefficient; Diffusion-weighted imaging; Short tau inversion recovery; Signal-to-noise ratio
Authors: Wolfgang Bogner; Stephan Gruber; Katja Pinker; Günther Grabner; Andreas Stadlbauer; Michael Weber; Ewald Moser; Thomas H Helbich; Siegfried Trattnig Journal: Radiology Date: 2009-07-31 Impact factor: 11.105