Thin-section diffusion-weighted magnetic resonance imaging of the brain with parallel imaging.
BACKGROUND
Thin-section diffusion-weighted imaging (DWI) is known to improve lesion detectability, with long imaging time as a drawback. Parallel imaging (PI) is a technique that takes advantage of spatial sensitivity information inherent in an array of multiple-receiver surface coils to partially replace time-consuming spatial encoding and reduce imaging time.


OBJECTIVE
To prospectively evaluate a 3-mm-thin-section DWI technique combined with PI by means of qualitative and quantitative measurements.


METHODS
30 patients underwent conventional echo-planar (EPI) DWI (5-mm section thickness, 1-mm intersection gap) without parallel imaging, and thin-section EPI-DWI with PI (3-mm section thickness, 0-mm intersection gap) for a b value of 1000 s/mm(2), with an imaging time of 40 and 80 s, respectively. Signal-to-noise ratio (SNR), relative signal intensity (rSI), and apparent diffusion coefficient (ADC) values were measured over a lesion-free cerebral region on both series by two radiologists. A quality score was assigned for each set of images to assess the image quality. When a brain lesion was present, contrast-to-noise ratio (CNR) and corresponding ADC were also measured. Student t-tests were used for statistical analysis.


RESULTS
Mean SNR values of the normal brain were 33.61+/-4.35 and 32.98+/-7.19 for conventional and thin-slice DWI (P>0.05), respectively. Relative signal intensities were significantly higher on thin-section DWI (P<0.05). Mean ADCs of the brain obtained by both techniques were comparable (P>0.05). Quality scores and overall lesion CNR were found to be higher in thin-section DWI with parallel imaging.


CONCLUSIONS
A thin-section technique combined with PI improves rSI, CNR, and image quality without compromising SNR and ADC measurements in an acceptable imaging time.
Oner
A Y
AY
Department of Radiology, Gazi University School of Medicine, Besevler-Ankara, Turkey. yusuf@tr.net
Celik
H
H
Tali
T
T
Akpek
S
S
Tokgoz
N
N
D000328:Adult; D000368:Aged; D001921:Brain / Q000033:anatomy & histology; D001927:Brain Diseases / Q000175:diagnosis*; D020520:Brain Infarction / Q000175:diagnosis; D001932:Brain Neoplasms / Q000175:diagnosis / Q000556:secondary; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods; D004806:Ependymoma / Q000175:diagnosis; D005260:Female; D005909:Glioblastoma / Q000175:diagnosis; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013997:Time Factors