Three-Tesla MRI does not improve the diagnosis of multiple sclerosis: A multicenter study

Abstract

Objective: In the work-up of patients presenting with a clinically isolated syndrome (CIS), 3T MRI might offer a higher lesion detection than 1.5T, but it remains unclear whether this affects the fulfilment of the diagnostic criteria for multiple sclerosis (MS).

Methods: We recruited 66 patients with CIS within 6 months from symptom onset and 26 healthy controls in 6 MS centers. All participants underwent 1.5T and 3T brain and spinal cord MRI at baseline according to local optimized protocols and the MAGNIMS guidelines. Patients who had not converted to MS during follow-up received repeat brain MRI at 3-6 months and 12-15 months. The number of lesions per anatomical region was scored by 3 raters in consensus. Criteria for dissemination in space (DIS) and dissemination in time (DIT) were determined according to the 2017 revisions of the McDonald criteria.

Results: Three-Tesla MRI detected 15% more T2 brain lesions compared to 1.5T (p < 0.001), which was driven by an increase in baseline detection of periventricular (12%, p = 0.015), (juxta)cortical (21%, p = 0.005), and deep white matter lesions (21%, p < 0.001). The detection rate of spinal cord lesions and gadolinium-enhancing lesions did not differ between field strengths. Three-Tesla MRI did not lead to a higher number of patients fulfilling the criteria for DIS or DIT, or subsequent diagnosis of MS, at any of the 3 time points.

Conclusion: Scanning at 3T does not influence the diagnosis of MS according to McDonald diagnostic criteria.

Figure 1. Mean number of lesions detected per participant per anatomical region

(A, B) Graphs illustrate the significantly increased detection of periventricular, (juxta)cortical, and deep white matter lesions on 3T in patients with clinically isolated syndrome at baseline (A) and throughout the total study (B) when compared to 1.5T. (C) Graph demonstrates there was no effect of field strength on lesion detection in healthy controls in any anatomical region. As the number of lesions identified in healthy controls is much lower compared to patients, the scale of the graph has been adjusted. To correct for multiple testing, statistical significance was defined as p < 0.01.

Figure 2. Lesion detection on 1.5T and 3T

(A) Baseline fluid-attenuated inversion recovery brain imaging of a 28-year-old woman with clinically isolated syndrome presenting with optic neuritis. At 3T, more lesions were identified compared to 1.5T: periventricular lesions 6 vs 6, juxtacortical lesions 6 vs 3, and deep white matter lesions 12 vs 5. On both field strengths, no enhancing lesions were seen. This led to fulfilment of the 2017 revisions of the McDonald criteria for dissemination in space and not for dissemination in time at both 1.5T and 3T. Therefore the diagnosis of MS could not be made on both field strengths. So, even though high-field MRI increased the lesion detection of supratentorial demyelinating lesions in this patient, this did not change the diagnosis. (B) Baseline proton density spinal cord imaging of a 23-year-old man with clinically isolated syndrome, presenting with brainstem symptoms. Besides lesions in the brain, spinal cord lesions were identified on both field strengths. Even though there is a difference in image quality, an equal number of lesions were detected at 1.5T and 3T.