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The precision of T1 hypointense lesion volume quantification in multiple sclerosis treatment trials: a multicenter
P D Molyneux1, P A Brex, C Fogg
1NMR Research Unit, Institute of Neurology, National Hospital, Queen Square, London, UK.
Abstract:
The volume of hypointense lesions on T1 weighted brain MRI represents an increasingly used MR endpoint in phase III MS treatment trials. In this study we evaluated the reproducibility of hypointense T1 lesion volume quantification in a cohort of Multiple Sclerosis (MS) patients. The gadolinium enhanced T1 weighted brain MR images of 33 MS patients from three European centers were used in this study. These images were acquired as part of a phase III trial of interferon beta-1b in secondary progressive MS. The MRI machine manufacturers and imaging parameters varied according to the MRI acquisition center. Three experienced observers used a semi-automated local thresholding technique to quantify the hypointense T1 lesion volume on two occasions, separated by a delay. The intra and inter observer coefficients of variation were 3.7% and 4.9% respectively, with similar values derived for images obtained at all three sites. There was a generally high level of agreement between the lesion volumes obtained by the three raters. However, a modest but significant measurement drift was identified between the first and second sessions for one of the three raters, highlighting the very real possibility of measurement drift even for experienced observers. Our results support the increasing role for T1 hypointense lesion volume as an outcome measure in multicenter phase III MS treatment trials. Multiple Sclerosis (2000) 6 237 - 240
Insights
Reproducibility of T1 hypointense lesion volume quantification in Multiple Sclerosis (MS) patients is high. This MR endpoint is reliable for phase III MS treatment trials despite potential measurement drift.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- T1 hypointense lesions on brain MRI are a key endpoint in Multiple Sclerosis (MS) clinical trials.
- Standardizing quantification methods is crucial for reliable treatment outcome assessment.
Purpose of the Study:
- To evaluate the reproducibility of T1 hypointense lesion volume quantification in MS patients.
- To assess the reliability of this MR endpoint across multiple European centers.
Main Methods:
- 33 MS patients' gadolinium-enhanced T1-weighted brain MR images from a phase III trial were analyzed.
- Three experienced observers used a semi-automated local thresholding technique for quantification.
- Image acquisition varied across three European centers.
Main Results:
- High agreement was observed between lesion volumes quantified by the three raters.
- Intra- and inter-observer coefficients of variation were low (3.7% and 4.9%, respectively).
- A modest but significant measurement drift was noted for one rater between sessions.
Conclusions:
- T1 hypointense lesion volume quantification demonstrates good reproducibility in multicenter MS trials.
- This MR endpoint is a valuable tool for assessing treatment efficacy in MS.
- Awareness of potential measurement drift is important for experienced observers.