Optimization and Clinical Feasibility of Free-breathing Diffusion-weighted Imaging of the Liver: Comparison with Respiratory-Triggered Diffusion-weighted Imaging.
OBJECTIVE
We compared the image quality of free-breathing diffusion-weighted imaging (FB-DWI) to that of respiratory-triggered DWI (RT-DWI) after proper optimization.


METHODS
Three healthy subjects were scanned to optimize magnetic resonance (MR) parameters of FB-DWI to improve image quality, including spatial resolution, image noise, and chemical shift artifacts. After this optimization, we scanned 32 patients with liver disease to assess the clinical feasibility of the optimized FB-DWI. Of the 32 patients, 14 had a total of 28 hepatocellular carcinomas (HCCs), four had a total of 15 metastatic liver tumors, and the other 14 had no tumor. Qualitatively, we compared the image quality scores of FB-DWI with those of RT-DWI with the Wilcoxon signed-rank test. Quantitatively, we compared the signal-to-noise ratios (SNRs) of the liver parenchyma, lesion-to-nonlesion contrast-to-noise ratios (CNRs) and apparent diffusion coefficient (ADC) values of the liver parenchyma and liver tumor by the paired t-test.


RESULTS
The average scores of image quality for sharpness of liver contour, image noise, and chemical shift artifacts were significantly higher for FB-DWI than RT-DWI (P < 0.05). SNRs, CNRs, and ADC values of the liver parenchyma and tumors did not differ significantly between the 2 DWI methods.


CONCLUSIONS
Compared with RT-DWI, the optimized FB-DWI provided better spatial resolution, fewer artifacts, and comparable SNRs, lesion-to-nonlesion CNRs, and ADC values.
Department of Radiology Informatics and Network, Graduate School of Medical Sciences, Kyushu University.
Yukihisa
Y
Takayama
Akihiro
A
Nishie
Yoshiki
Y
Asayama
Kousei
K
Ishigami
Daisuke
D
Kakihara
Yasuhiro
Y
Ushijima
Nobuhiro
N
Fujita
Takashi
T
Yoshiura
Atsushi
A
Takemura
Makoto
M
Obara
Taro
T
Takahara
Hiroshi
H
Honda
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000175:diagnosis / Q000556:secondary; D064368:Healthy Volunteers; D019694:Hepatitis B, Chronic / Q000175:diagnosis; D019698:Hepatitis C, Chronic / Q000175:diagnosis; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008099:Liver / Q000033:anatomy & histology*; D008103:Liver Cirrhosis / Q000175:diagnosis; D008107:Liver Diseases / Q000175:diagnosis*; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000556:secondary; D008297:Male; D008875:Middle Aged; D012119:Respiration; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D059629:Signal-To-Noise Ratio