Early Detection of Global Cerebral Anoxia: Improved Accuracy by High-b-Value Diffusion-Weighted Imaging with Long Echo Time

ADC values of abnormal and normal regions of interest of the patients, measurable at b = 1000 s/mm² (A) and at b = 3000 s/mm² (B). For each column, the uppermost point indicates the maximum ADC value. The middle point indicates the mean ADC value, and the lowermost point the minimum. The bars indicate SDs.

The ROC curves of each MR image achieved by the three observers. The high-b-value DWI holds the largest area under the curve (Az). The Az of the routine DWI (b = 1000 s/mm²), T2WI, and FLAIR imaging follow in descending order.

Histogram showing Az for each MR image and observer. Asterisk represents statistical significance (P < .05 by univariate z score test). For all observers, the high-b-value DWI achieves the largest Az. For observer 1, Az between any two sequences shows statistically significant difference. For observer 2, the statistically significant difference is noted between the high-b-value DWI or FLAIR images and any other sequences. No significant difference is observed between routine DWI and T2WI. For observer 3, statistically significant difference is noted between any two sequences, except for Az between T2WI and FLAIR imaging.

Routine DW image of a patient (A). High-b-value DW image (B). T2-weighted image (C). FLAIR image (D). The signal intensity abnormalities of bilateral cerebral cortex are more conspicuous on the high-b-value DWI.

Routine DW image of another patient (A). High-b-value DW image (B). T2-weighted image (C). FLAIR image (D). The signal intensity abnormalities of bilateral cerebral cortex and deep gray matter are more conspicuous on the high-b-value DWI.

The signal intensity attenuation curves for DWI. The horizontal (X) axis represents b value (b) and the vertical (Y) axis represents the logarithmic ratio of signal intensities (ln S[b]/S [0]).