Diffusion-weighted imaging in ischemic stroke: effect of display method on observers' diagnostic performance.
OBJECTIVE
When evaluating ischemic stroke on diffusion-weighted magnetic resonance imaging (DWI), the display method has not been investigated. The purpose of this study was to determine whether standardization of the display method for DWI affects observers' diagnostic performance in detecting ischemic stroke on DWI.


METHODS
Twenty-six observers evaluated 40 DWI studies in 20 patients with acute (< 6 hours) middle cerebral arterial strokes and 20 controls for the presence of hyperintense lesions in 10 areas using the Alberta Stroke Programme Early CT Score (ASPECTS) system and one area in the corona radiata using a modified version of the ASPECTS system (ASPECTS-DWI). The images were reviewed using a standardized display method (SDM) and a conventional display method (CDM). The reading time was recorded for each session. The observers' performance was evaluated with receiver-operating characteristic analysis.


RESULTS
In all observers with ASPECTS-DWI scores of < or = 8 points, the value of the mean average area under the receiver-operating characteristic curve was slightly higher for the SDM than the CDM, but the difference was not statistically significant. In the insular ribbon, diagnostic accuracy was significantly higher with the SDM than the CDM (P = .036). In the other locations, there were no significant differences. With the SDM, the mean reading time was reduced by 7.5 seconds (P = .024).


CONCLUSIONS
The SDM improved diagnostic accuracy for the insular ribbon and shortened the reading time, although it did not improve observers' performance with the ASPECTS-DWI system.
Hirai
Toshinori
T
Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan. t-hirai@kumamoto-u.ac.jp
Sasaki
Makoto
M
Maeda
Masayuki
M
Ida
Masahiro
M
Katsuragawa
Shigehiko
S
Sakoh
Masaharu
M
Takano
Koichi
K
Arai
Shoichi
S
Hirano
Teruyuki
T
Kai
Yutaka
Y
Kakeda
Shingo
S
Murakami
Ryuji
R
Ikeda
Ryuji
R
Fukuoka
Hirofumi
H
Sasao
Akira
A
Yamashita
Yasuyuki
Y
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000150:complications / Q000175:diagnosis*; D016288:Computer Terminals; D003626:Data Display; D038524:Diffusion Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020521:Stroke / Q000175:diagnosis* / Q000209:etiology