Accuracy of Unenhanced MRI in the Detection of
New Brain Lesions in Multiple Sclerosis.
Eichinger P, Schön S, Pongratz V, Wiestler H, Zhang H, Bussas M, Hoshi MM, Kirschke J, Berthele A, Zimmer C, Hemmer B, Mühlau M, Wiestler B.
Radiology. 2019 Mar 12:181568. doi: 10.1148/radiol.2019181568. [Epub ahead of print]
Key Points:
1. Detecting signs of clinically silent disease progression in persons with MS is critical for two reasons. First is to decide if treatment with disease-modifying therapies is needed in a person with an isolated episode of central nervous system disease that could become MS. The second is to decide if treatment with a disease-modifying therapy is controlling MS-related disease activity.
2. While a person’s history and careful neurologic exam remain essential for determining disease activity in MS, preforming periodic brain and spinal cord MRIs to detect new lesions is also important.
3. At the time of diagnosing MS it is necessary to perform brain and spinal cord MRIs with and without the addition of the vein-administered (IV) contrast medium, gadolinium. Lesions that show the presence of contrast (contrast enhancing lesions) are, in the proper context, an indication of active inflammation and support a diagnosis of MS.
4. Gadolinium is expensive and carries a small risk of serious complications in persons with severe kidney disease. Recent observations also suggest that some forms of gadolinium remain in the body for long periods of time, though no long-term effects have been noted.
5. The paper noted above asked the important question: Can one detect new lesions in the central nervous system of persons with MS without the use of gadolinium?
6. In their study of 359 persons with MS, with 507 follow-up MRIs, 1,992 new lesions were noted with 207 showing contrast enhancement. Only 9 lesions were only seen with injection of contrast. However, using multiple MRI techniques no lesions were missed when contrast was omitted.
7. The bottom line: Injecting contrast is needed when using central nervous system MRIs to help in the diagnosis of MS, but may not be necessary after that when just looking for evidence of silent disease progression.
The criteria for establishing a diagnosis of MS have changed greatly in the past several decades. The most established criteria are the McDonald Criteria, named after the chairman of the committee that first established them. They have been modified over time, with the most recent modifications occurring in 2017. Central nervous system MRIs that show the presence of brain or spinal cord lesions containing the contrast medium, gadolinium indicate a breakdown of the blood brain barrier. In the proper context of a person’s history and neurologic exam, they also indicate the presence of new or acute inflammation in the central nervous system. Again, in the proper context, and if consistent with McDonald Criteria, such findings support a diagnosis of MS. Because of this, performing central nervous system MRIs with contrast is an essential part of the initial testing necessary to make a diagnosis of MS. However, as the paper by Eichinger and others noted above shows, injections of contrast are not needed to determine if new or worsened lesions are noted in subsequent central nervous system MRIs. Thus, neurologists will still be able to determine the presence of subclinical disease activity and the effectiveness of a disease-modifying therapy with a less expensive test that also reduces any risks that may occur with repeated injections of gadolinium.
The abstract of the article is available.