Background: In multiple sclerosis (MS), chronic lesions harboring a paramagnetic rim were neuropathologically related with activated microglia, an expanding lesion pattern and a poor prognosis. However, while the presence of this feature differs between patients and it is present only in a subset of lesions, it is still uncertain how it relates with overall lesion load, stage or disease aggressiveness. Aim: We used ultra-high resolution 7T scans on a cohort of 91 subjects at different MS stages to: i) assess the presence and distribution of paramagnetic rims throughout MS stages ii) explore whether the presence of the paramagnetic rims is linked with overall lesion load, pathological changes in normal appearing white matter (NAWM), as well as with clinical disability and cortical tissue loss. Methods: Sixty-two relapsing remitting (RRMS) and 29 secondary progressive MS (SPMS) patients, underwent: 7T T2*-weighted scans (0.33x0.33x1.0 mm) yielding magnitude and phase images for cortical and white matter lesion segmentation; 3T 3D T1-weighted scans for surface reconstruction and cortical thickness estimation. Conventional diffusion metrics were acquired in a subset of 72 patients. Expanded Disability Status Scale and Symbol Digit Modality Test evaluated the clinical status. Paramagnetic rim was appreciated on phase images and patients were dichotomized based on its presence or absence. The differences between groups were assessed by nonparametric statistics and analysis of covariance. Results: Overall, 174 (median 1, range1-16) rim lesions were identified in 55 (60.4%) patients. Rim lesion load was the same across MS phenotypes though there were large individual differences (RRMS: median 1 range 0-14 vs. SPMS: median 1 range 1-16 lesions). Concurrently, both white matter (median 25 vs. 45 lesions, p=0.028) and cortical (median 5.5 vs. median 11 lesions, p=0.014) lesion load was higher in patients with rim lesions than in patients without rim lesions. The two groups did not differ from each other regarding age, disease duration, NAWM fractional anisotropy and mean diffusivity, cortical thickness and clinical measures. Conclusion: The presence of rim lesions might be linked to an accelerated phase of the disease in respect to the development of an increased number of MS lesions. Further longitudinal studies are needed to unveil their true significance.
The relevance of 7-Tesla paramagnetic rim lesions in patients with multiple sclerosis / Treaba, C.; Granberg, T.; Herranz, E.; Mercaldo, N.; Barletta, V.; Mehndiratta, A.; Ouellette, R.; Sloane, J.; Kinkel, R.; Mainero, C.. - (2019). (Intervento presentato al convegno ECTRIMS 2019 tenutosi a Stoccolma).
The relevance of 7-Tesla paramagnetic rim lesions in patients with multiple sclerosis
V. Barletta;
2019
Abstract
Background: In multiple sclerosis (MS), chronic lesions harboring a paramagnetic rim were neuropathologically related with activated microglia, an expanding lesion pattern and a poor prognosis. However, while the presence of this feature differs between patients and it is present only in a subset of lesions, it is still uncertain how it relates with overall lesion load, stage or disease aggressiveness. Aim: We used ultra-high resolution 7T scans on a cohort of 91 subjects at different MS stages to: i) assess the presence and distribution of paramagnetic rims throughout MS stages ii) explore whether the presence of the paramagnetic rims is linked with overall lesion load, pathological changes in normal appearing white matter (NAWM), as well as with clinical disability and cortical tissue loss. Methods: Sixty-two relapsing remitting (RRMS) and 29 secondary progressive MS (SPMS) patients, underwent: 7T T2*-weighted scans (0.33x0.33x1.0 mm) yielding magnitude and phase images for cortical and white matter lesion segmentation; 3T 3D T1-weighted scans for surface reconstruction and cortical thickness estimation. Conventional diffusion metrics were acquired in a subset of 72 patients. Expanded Disability Status Scale and Symbol Digit Modality Test evaluated the clinical status. Paramagnetic rim was appreciated on phase images and patients were dichotomized based on its presence or absence. The differences between groups were assessed by nonparametric statistics and analysis of covariance. Results: Overall, 174 (median 1, range1-16) rim lesions were identified in 55 (60.4%) patients. Rim lesion load was the same across MS phenotypes though there were large individual differences (RRMS: median 1 range 0-14 vs. SPMS: median 1 range 1-16 lesions). Concurrently, both white matter (median 25 vs. 45 lesions, p=0.028) and cortical (median 5.5 vs. median 11 lesions, p=0.014) lesion load was higher in patients with rim lesions than in patients without rim lesions. The two groups did not differ from each other regarding age, disease duration, NAWM fractional anisotropy and mean diffusivity, cortical thickness and clinical measures. Conclusion: The presence of rim lesions might be linked to an accelerated phase of the disease in respect to the development of an increased number of MS lesions. Further longitudinal studies are needed to unveil their true significance.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
