Is low b-factors-based apparent diffusion coefficient helpful in assessing renal dysfunction?
OBJECTIVE
To investigate whether low b-factors-based apparent diffusion coefficient (ADC) is helpful in assessing renal dysfunction.


METHODS
Forty-four subjects were recruited, and classified as having severe renal injury group (sRI) or not (non-sRI) according to a threshold of estimated glomerular filtration rate (eGFR) = 30 ml/min/1.73 m(2). A free-breathing DWI with 7 b-factors (0, 20, 40, 80, 200, 400, and 800 s/mm(2)) was performed. After choosing an anatomical section that covered the largest part of right kidney, the regions of interest covered the renal parenchyma. For each subject, two apparent diffusion coefficients based on all b-factors less than 400 s/mm(2) (ADC0-400) and 800 s/mm(2) (ADC0-800) were calculated by fitting the signal intensity at different b-factors to a mono-exponential decay, respectively. It was found that the examination time of the free-breathing DWI sequence in this study can be reduced from 3.27 to 2.55 min if the b-factor (800 s/mm(2)) is removed.


RESULTS
ADC0-400 was larger than ADC0-800 in each group (P < 0.05). Both ADC0-400 and ADC0-800 were smaller in the sRI group than those in the non-sRI group (P < 0.01), and they were linearly related with eGFR (P < 0.05). While a significant difference was not found between the two coefficients to differentiate sRI from non-sRI participants (P > 0.05), a strong correlation was present between ADC0-400 and ADC0-800 (r = 0.856, P < 0.001).


CONCLUSIONS
The low b-factors-based ADC was an economical option for reducing the examination time without sacrificing its diagnostic performance.
Department of Radiology, Third Affiliated Hospital of Suzhou University, Changzhou, 213003, Jiangsu, China.
Jiule
J
Ding
Department of Radiology, Third Affiliated Hospital of Suzhou University, Changzhou, 213003, Jiangsu, China.
Jie
J
Chen
Department of Radiology, Third Affiliated Hospital of Suzhou University, Changzhou, 213003, Jiangsu, China.
Zhenxing
Z
Jiang
Department of Nephrology, Third Affiliated Hospital of Suzhou University, Changzhou, 213003, Jiangsu, China.
Hua
H
Zhou
Department of Nephrology, Third Affiliated Hospital of Suzhou University, Changzhou, 213003, Jiangsu, China.
Jia
J
Di
Department of Radiology, Third Affiliated Hospital of Suzhou University, Changzhou, 213003, Jiangsu, China.
Shijun
S
Xing
Department of Radiology, Third Affiliated Hospital of Suzhou University, Changzhou, 213003, Jiangsu, China. suzhxingwei@126.com.
Wei
W
Xing
D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007674:Kidney Diseases / Q000175:diagnosis*; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged
Apparent diffusion coefficient; Diffusion-weighted imaging; Magnetic resonance imaging