Assessment of Diffusion-Weighted Imaging-FLAIR Mismatch: Comparison between Conventional FLAIR versus Shorter-Repetition-Time FLAIR at 3T.
10.13104/imri.2016.20.2.88
- Author:
Byeong Ho GOH
1
;
Eung Yeop KIM
Author Information
1. Department of Radiology, Gachon University Gil Medical Center, Incheon, Korea. neuroradkim@gmail.com
- Publication Type:Original Article
- Keywords:
Acute ischemic stroke;
Magnetic resonance imaging;
Diffusion-weighted imaging;
Fluid-attenuated inversion recovery
- MeSH:
Humans;
Magnetic Resonance Imaging;
Stroke
- From:Investigative Magnetic Resonance Imaging
2016;20(2):88-94
- CountryRepublic of Korea
- Language:English
-
Abstract:
PURPOSE: Fluid-attenuated inversion recovery (FLAIR) imaging can be obtained faster with shorter repletion time (TR), but it gets noisier. We hypothesized that shorter-TR FLAIR obtained at 3 tesla (3T) with a 32-channel coil may be comparable to conventional FLAIR. The aim of this study was to compare the diagnostic value between conventional FLAIR (TR = 9000 ms, FLAIR9000) and shorter-TR FLAIR (TR = 6000 ms, FLAIR6000) at 3T in terms of diffusion-weighted imaging-FLAIR mismatch. MATERIALS AND METHODS: We recruited 184 patients with acute ischemic stroke (28 patients < 4.5 hours) who had undergone 5-mm diffusion-weighted imaging (DWI) and two successive 5-mm FLAIR images (no gap; in-plane resolution, 0.9 × 0.9 mm) at 3T with a 32-channel coil. The acquisition times for FLAIR9000 and FLAIR6000 were 108 seconds (generalized autocalibrating partially parallel acquisitions [GRAPPA] = 2) and 60 seconds (GRAPPA = 3), respectively. Two radiologists independently assessed the paired imaging sets (DWI-FLAIR9000 and DWI-FLAIR6000) for the presence of matched hyperintense lesions on each FLAIR imaging. The signal intensity ratios (area of DWI lesion to contralateral normal-appearing region) on both FLAIR imaging sets were compared. RESULTS: DWI-FLAIR9000 mismatch was present in 39 of 184 (21.2%) patients, which was perfectly the same on FLAIR6000. Three of 145 patients (2%) with DWI-matched lesions on FLAIR9000 had discrepancy on FLAIR6000, showing no significant difference (P > 0.05). Interobserver agreement was excellent for both DWI-FLAIR9000 and DWI-FLAIR6000 (k = 0.904 and 0.883, respectively). Between the two FLAIR imaging sets, there was no significant difference of signal intensity ratio (mean, standard deviation; 1.25 ± 0.20; 1.24 ± 0.20, respectively) (P > 0.05). CONCLUSION: For the determination of mismatch or match between DWI and FLAIR imaging, there is no significant difference between FLAIR9000 and FLAIR6000 at 3T with a 32-channel coil.
