Multiple sclerosis: interobserver agreement in reporting active lesions on serial brain MRI using conventional spin
M Rovaris1, F Barkhof, S Bastianello
1Neuroimaging Research Unit, Department of Neuroscience, Scientific Institute Ospedale San Raffaele, Via Olgettina, 60, I-20132 Milan, Italy.
Abstract:
Previous studies have addressed the question of the precision in assessing multiple sclerosis (MS) activity by counting enhancing lesions on gadolinium enhanced brain magnetic resonance imaging (MRI). However, counting the active lesions on serial unenhanced MRI obtained by various pulse sequences has not been yet considered. We compared the interobserver levels of agreement in reporting active MS lesions on serial enhanced and unenhanced MRI to assess whether the use of various unenhanced techniques may change the degree of interobserver measurement reproducibility. Dual-echo conventional spin echo (CSE), dual-echo fast spin echo (FSE), fast fluid-attenuated inversion recovery (FLAIR) and Gd-enhanced T1-weighted brain MRI were obtained from five MS patients at baseline and monthly for 2 months. Six experienced observers independently identified and counted active MS lesions on the two follow-up MRI scans. Active lesions were considered to be all the enhancing lesions and any new or enlarging lesion on enhanced and unenhanced scans. Interobserver levels of agreement were calculated by weighted kappa values. Very good agreement was reached only for counting total and new Gd-enhancing lesions. Good agreement was achieved for counting new lesions on the three unenhanced techniques, whereas the agreement for counting enlarging lesions was poor with all the MRI techniques. The level of agreement was significantly heterogeneous for various MRI techniques but not for various lesion sites. These results confirm that counting enhancing lesions is the most reliable method for assessing MS activity, but the use of any of the available unenhanced MRI techniques did not result in different levels of interobserver agreement when reporting new and enlarging MS lesions on serial scans.
Insights
Counting gadolinium-enhancing lesions on MRI is the most reliable method for assessing multiple sclerosis (MS) activity. Unenhanced MRI techniques did not significantly alter interobserver agreement for new or enlarging MS lesions.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Assessing multiple sclerosis (MS) activity relies on detecting new or enlarging lesions via MRI.
- Gadolinium-enhanced MRI is standard, but unenhanced techniques' precision is less understood.
Purpose of the Study:
- To compare interobserver agreement in identifying active MS lesions using enhanced versus various unenhanced MRI sequences.
- To determine if unenhanced MRI techniques affect the reproducibility of MS lesion assessment.
Main Methods:
- Six observers evaluated serial enhanced and unenhanced MRI scans (CSE, FSE, FLAIR) from five MS patients over two months.
- Active lesions included enhancing, new, or enlarging lesions.
- Interobserver agreement was quantified using weighted kappa values.
Main Results:
- Very good agreement was found solely for counting total and new gadolinium-enhancing lesions.
- Good agreement was observed for new lesions on unenhanced MRI techniques.
- Poor agreement was noted for enlarging lesions across all MRI techniques.
Conclusions:
- Counting gadolinium-enhancing lesions remains the most reliable method for MS activity assessment.
- Unenhanced MRI techniques did not significantly change interobserver agreement for reporting new and enlarging MS lesions on serial scans.
