# qT1 Repeatability and Minimal Detectable Change in MS Lesions from an 8 minute Brain and Cervical Spinal Cord MRI Acquisition

Nolwenn Jégou, Malo Gaubert, Virginie Callot, Catherine Guillemot, Elise

Bannier, Anne Kerbrat, Benoit Combès

► To cite this version:

Nolwenn Jégou, Malo Gaubert, Virginie Callot, Catherine Guillemot, Elise Bannier, et al., qT1 Repeatability and Minimal Detectable Change in MS Lesions from an 8 minute Brain and Cervical Spinal Cord MRI Acquisition. ECTRIMS 2025 - 41st Congress of the European Committee for Treatment and Research in Multiple Sclerosis and the 30th Conference of Rehabilitation in Multiple Sclerosis (RIMS), Sep 2025, Barcelona, Spain. pp.1-1, 2025. [hal-05298931](https://hal.science/hal-05298931v1)

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https://hal.science/hal-05298931v1

Submitted on 6 Oct 2025

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# qT1 Repeatability and Minimal Detectable Change in MS Lesions from an 8 minute Brain and Cervical Spinal Cord MRI Acquisition

Nolwenn Jégou¹, Malo Gaubert ¹,², Virginie Callot ³,⁴, Catherine Guillemot ², Elise Bannier ¹,², Anne Kerbrat ⁵, Benoît Combès ¹

nolwenn.jegou@inria.fr

¹ University Rennes, Inria, CNRS, Inserm, IRISA UMR 6074, Empenn U1228, Rennes; ² CHU Rennes, Department of Radiology, Rennes; ³ Assistance Publique-Hopitaux de Marseille, Hôpital Universitaire Timone, CEMEREM, Marseille; ⁴ Aix-Marseille Université, CNRS, CRMBM, Marseille; ⁵ CHU Rennes, Department of Neurology, Rennes.

## CONTEXT

- MP2RAGE is a fast quantitative T1 (qT1) [1] MRI sequence offering simultaneous imaging of the brain and cervical spinal cord (SC) in 8 minutes [2].

- It enables MS lesion detection [3] and assessment of microstructural tissue damage and its changes over time.

- Measuring variations in T1 values linked to microstructural changes requires good repeatability and understanding of the main factors influencing T1 values.

<figure><img src="image_2.png" /></figure>

## OBJECTIVES

- To study the repeatability of T1 mapping in MS lesions in the brain and in the spinal cord

- To assess the ability of the MP2RAGE sequence to capture T1 increase/decrease in lesions at 1-year, approximating demyelination/remyelination.

## MATERIALS ET METHODS

**Repeatability cohort:** 11 patients with MS (pwMS) scanned twice less than 30 days apart on the same MRI. Mean age is 40.4 y.o., percentage of women is 72%, average EDSS is 1.7.

**Longitudinal cohort:** 25 pwMS scanned twice 1 year apart on the same MRI. Mean age is 43.9 y.o., percentage of women is 72%, average EDSS is 1.8.

### IRM Siemens Prisma 3T :

- 3D FLAIR (1×1×1mm³, 4m20s)

- MP2RAGE (0.9×0.9×1mm³, 8m18s)

The image processing is done with Anima (4.2) [6] and the SCT (6.4) [2].

- B1 correction of qT1 maps [4].

- Lesions are segmented on both sessions, the union of both masks is used as region of interest.

- Brain lesions are segmented with an internal deep learning tool on 3D FLAIR images.

- SC lesions are segmented with the SCT [5] on the MP2RAGE images.

## RESULTS

<table><caption>**Mean T1 values in the brain and in the spinal cord**</caption><thead><tr><th></th><th>Brain (N=429 lesions)</th><th>SC (N=40 lesions)</th></tr></thead><tbody><tr><td>Lesions</td><td>1114.3 (172.4)</td><td>1227.9 (123.0)</td></tr><tr><td>Normal app. tissues</td><td>943.6 (47.0)</td><td>1026.2 (52.9)</td></tr><tr><td>p-value</td><td>10<sup>-4</sup></td><td>10<sup>-4</sup></td></tr></tbody></table>

<caption>**Figure 1:** Mean T1 (SD) values in ms and p-value for no difference between lesions and normal appearing tissues.</caption>

➤ We observe higher mean T1 values in lesions as compared to normal appearing tissues in the brain and in the spinal cord.

**FUNDINGS** This work was supported in part by ANR through the France 2030 programme (ANR-21-RHUS-0014).

**REFERENCES** [1] Marques J. P., Neuroimage 2010. [2] Forodighasemabadi A., MRI 2021. [3] Demortière S., AJNR 2020. [4] Massire A., Neuroimage 2016. [5] Laines Medina N., ESMRMB, 2024. [6] Vidal-Migallón I., Insight Journal (ITK), 2013.

**DISCLOSURE** Nolwenn Jégou, Malo Gaubert, Virginie Callot, Quentin Duché, Catherine Guillemot, Elise Bannier, Anne Kerbrat, Benoît Combès : nothing to disclose.

<table><caption>**Repeatability of mean T1 in lesions**</caption><thead><tr><th></th><th>Brain & SC</th><th>Sublocations</th><th>Lesion volume</th><th>Patient / acquisition</th></tr></thead><tbody><tr><td>Brain lesions</td><td rowspan="2">5.7 10<sup>-10</sup></td><td>0.001</td><td>0.096</td><td>0.393</td></tr><tr><td>SC lesions</td><td>0.315</td><td>0.117</td><td>0.232</td></tr></tbody></table>

**Figure 2:** p-value associated with no difference between mean T1 scan rescan difference in lesions according to different lesion characteristics. Sublocations of lesions in the brain are white matter (WM), juxtacortical, periventricular and posterior fossa and in the SC are vertebrae levels. Lesions were categorized based on volume distribution with the following intervals : 44.2 and 119.9 mm³.

➤ Repeatability in lesions varies depending on its location in the central nervous system.

<table><caption>**Minimal detectable change in lesions according to its location**</caption><thead><tr><th>Location</th><th></th><th>(upper, lower) threshold in ms</th></tr></thead><tbody><tr><td rowspan="4">Brain</td><td>White matter</td><td>(25.1, -25.1)</td></tr><tr><td>Periventricular</td><td>(61.2, -61.2)</td></tr><tr><td>Juxtacortical</td><td>(36.9, -36.9)</td></tr><tr><td>Posterior fossa</td><td>(43.2, -43.2)</td></tr><tr><td>Spinal cord</td><td></td><td>(103.4, -103.4)</td></tr></tbody></table>

**Figure 3:** The MDC thresholds are the 90th quantile of the mean T1 scan rescan difference centered around 0. These thresholds have a 90% detection rate specificity.

➤ Lesions are the most repeatable when located in the brain WM and the least repeatable are in the SC.

<figure><img src="image_3.png" /><figcaption>**Figure 4:** Percentage of mean T1 value changes in lesions in each patient exceeding the ceiling (red) and floor (blue) MDC threshold.</figcaption></figure>

➤ We are able to detect on year mean T1 changes exceeding the MDC threshold in lesions.

## DISCUSSION & CONCLUSION

The repeatability of mean T1 in lesions is different across the nervous system and the location needs to be taken into account in longitudinal studies.

Using location specific thresholds allows to highlight a high percentage of lesion exceeding MDC threshold over one year, potentially identifying demyelinating or remyelinating lesions.

Future work will involve analysis of multicenter longitudinal cohort data and correlation with disability progression.