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[Fast spin echo and fast fluid attenuated inversion recovery sequences in multiple sclerosis]
A Paolillo1, E Giugni, A Bozzao
1Dipartimento di Scienze Neurologiche, Università, La Sapienza, Roma.
Abstract:
Fast spin echo (FSE) and fast fluid attenuated inversion recovery (fast-FLAIR) MR sequences were compared with conventional spin echo (CSE) in quantitating multiple sclerosis (MS) lesion burden. For each sequence, the total number and volume of MS lesions were calculated in 38 remitting MS patients using a semiautomated lesion detection program. CSE, FSE and fast-FLAIR images were reported on randomly and at different times by two expert observers. Interobserver differences, the time needed to quantitate MS lesions and lesion signal intensity (contrast-to-noise ratio and overall contrast) were considered. The lesions were classified by site into infratentorial, white matter and cortical/subcortical. A total of 2970 lesions with a volume of 961.7 cm3 was calculated on CSE images. FSE images depicted fewer (16.6%; p < .005) and smaller (24.9%; p < .0001) lesions and the differences were statistically significant. Despite an overall nonsignificant reduction for fast-FLAIR images (.5% and 4.8% for lesion number and volume, respectively), significantly lower values (lesion number: p < .01; volume: p < .04) were observed for infratentorial lesions, while significantly higher values were seen for cortical/subcortical lesions (lesion number: p < .01; volume: p < .02). A higher lesion/white matter contrast (p < .002), a significant time saving for lesion burden quantitation (p < .05) and very low interobserver variability were found in favor of fast-FLAIR. Our data suggest that, despite the limitations regarding infratentorial lesions, fast-FLAIR sequences are indicated in MS studies because of their good identification of cortical/subcortical lesions, almost complete interobserver agreement, higher contrast-to-noise ratio and the limited time needed for semiautomated quantitation.
Insights
Fast fluid attenuated inversion recovery (fast-FLAIR) MRI sequences offer improved lesion detection and reduced quantitation time in multiple sclerosis (MS) studies compared to conventional spin echo (CSE). While FSE sequences detected fewer lesions, fast-FLAIR demonstrated better identification of cortical lesions and higher contrast.
Area of Science:
- Radiology and Imaging
- Neurology
- Medical Physics
Background:
- Accurate quantitation of multiple sclerosis (MS) lesion burden is crucial for disease monitoring and treatment efficacy.
- Conventional spin echo (CSE) MRI sequences are established but may have limitations in lesion detection and quantitation efficiency.
- Fast spin echo (FSE) and fast fluid attenuated inversion recovery (fast-FLAIR) are advanced MRI techniques offering potential improvements.
Purpose of the Study:
- To compare the efficacy of FSE and fast-FLAIR sequences against CSE in quantifying MS lesion burden.
- To evaluate interobserver variability, time efficiency, and lesion signal intensity across different MRI sequences.
- To assess the performance of these sequences in detecting lesions across various brain regions (infratentorial, white matter, cortical/subcortical).
Main Methods:
- A semiautomated lesion detection program was used to calculate the number and volume of MS lesions on CSE, FSE, and fast-FLAIR images from 38 remitting MS patients.
- Two expert observers independently analyzed the images, with interobserver differences, quantitation time, and lesion signal intensity (contrast-to-noise ratio) recorded.
- Lesions were classified by location: infratentorial, white matter, and cortical/subcortical.
Main Results:
- CSE identified 2970 lesions totaling 961.7 cm³. FSE detected significantly fewer (16.6%) and smaller (24.9%) lesions compared to CSE.
- Fast-FLAIR showed a nonsignificant overall reduction in lesion number (0.5%) and volume (4.8%) but significantly detected fewer infratentorial lesions while identifying more cortical/subcortical lesions.
- Fast-FLAIR demonstrated superior lesion-to-white matter contrast, significantly reduced quantitation time, and minimal interobserver variability.
Conclusions:
- Fast-FLAIR sequences are recommended for MS studies due to their ability to identify cortical/subcortical lesions, high contrast-to-noise ratio, and efficient semiautomated quantitation.
- Despite limitations with infratentorial lesions, fast-FLAIR offers advantages in lesion detection and analysis speed over CSE and FSE.
- The high interobserver agreement and time savings make fast-FLAIR a valuable tool for MS lesion burden assessment.