Detection of groundglass opacities by use of hybr

Authors: Ko Higuchi Michinobu Nagao Yoshio Matsuo Shunya Sunami Takeshi Kamitani Mikako Jinnouchi Masato Yonezawa Yuzo Yamasaki Hidetake Yabuuchi Masamitsu Hatkenaka Hiroshi Honda

Publish Date: 2013/02/12

Volume: 6, Issue: 2, Pages: 299-304

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Abstract

The detection of groundglass opacities GGOs is an important issue in lung cancer screening with lowdose CT The iterative reconstruction IR technique has the ability to improve the image quality relative to the filtered back projection FBP technique with lowdose CT Our purpose was to investigate the ability to detect GGO in a chest phantom using a lowdose CT and hybrid IR named iDose Simulated GGOs in a chest phantom were scanned with 256section CT at tube current second products of 20 50 100 and 200 mAs Five radiologists visually assessed the detectability of GGOs in the phantom The contrasttonoise ratio CNR for GGOs was used as an estimate of image quality Comparison of the detectability and CNR between standard images with 200 mAsFBP and lowdose images with 20 50 and 100mAs FBP/iDose were performed by ANOVA with Dunnett’s and Tukey’s test The detectability was significantly lower at 20mAs FBP/iDose and 50mAs FBP than that at 200mAs FBP p  005 There was no significant difference between 50mAs iDose and 200mAs FBP and between 100mAs iDose/FBP and 200mAs FBP The CNR was significantly higher on iDose images than that on FBP images at each mAs value The CNR at 200mAs FBP was the same as that at 50mAs iDose CNR18 The hybrid IR technique and lowdose CT imaging with 50 mAs enabled noise and to maintain the detectability for GGOs in a chest phantom that is equivalent to the reference acquisitions of 200 mAs with FBP

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