Study: 7T MRI depicts MS lesions
Ultrahigh-field strength, T1-weighted magnetization-prepared rapid acquisition and multiple gradient echoes (MPRAGE) is highly sensitive for detecting multiple sclerosis (MS) plaques within the white and gray brain parenchyma, according to a study published online Feb. 20 in Archives of Neurology, one of the JAMA/Archives journals.
In current clinical practice, T2-weighted MRI is commonly used to quantify the accumulated MS lesion load in the brain, whereas T1-weighted sequences are used to differentiate irreversible brain tissue damage, hyperintense lesions commonly called “black holes.” Black holes are associated with clinical worsening and cerebral atrophy. On spin-echo T1-weighted images, a proportion of T2 hyperintense lesions appears hypointense to the surrounding normal-appearing white matter for a long time, the researchers noted.
Tim Sinnecker, of the NeuroCure Clinical Research Center, Charite University Medicine, Berlin, and colleagues enrolled 20 patients with relapsing-remitting MS and 14 healthy controls to undergo 7T MRI. A subgroup of 18 patients with MS also underwent 1.5T MRI.
“Against the background of the unresolved dispute over the clinical significance of black holes, and the increasing appreciation of gray matter pathology in MS, we investigated whether the visibility of T1 and T2 lesions in both gray and white matter would be influenced by the improved signal-to-noise ratio at 7T,” the authors wrote. “In particular, we hypothesized that the application of MPRAGE would facilitate the detection of hypointense lesions in comparison with conventional MRI.”
The 7T MPRAGE sequences detected a total number of 728 lesions, depicting more lesions than 7T FLASH (fast low-angle shot) and almost twice as much as 1.5T MPRAGE. Each of the 217 T1 hypointense lesions detected by the 7T MPRAGE sequences in the longitudinal subgroup persisted without major change in formation or size for at least one year and could thus be classified as a black hole, according to Sinnecker and colleagues.
Because the lesions did not change appearance over one year, the researchers suggested that they may express brain parenchymal destruction rather than temporary edema.
The researchers noted that the lesions were visualized with greater distinction concerning shape and appearance on the 7T MPRAGE images than via the 7T FLASH.
“To our knowledge, the present study is the first to demonstrate that, at ultrahigh-field strength, every T2 hyperintense lesion detected on T2-weighted FLASH sequences directly corresponds to a T1 hypointense lesion on a MPRAGE sequence,” the researchers concluded.
To read more about 7T MRI, read “7T MRI Sharpens its Focus”, in Health Imaging.
In current clinical practice, T2-weighted MRI is commonly used to quantify the accumulated MS lesion load in the brain, whereas T1-weighted sequences are used to differentiate irreversible brain tissue damage, hyperintense lesions commonly called “black holes.” Black holes are associated with clinical worsening and cerebral atrophy. On spin-echo T1-weighted images, a proportion of T2 hyperintense lesions appears hypointense to the surrounding normal-appearing white matter for a long time, the researchers noted.
Tim Sinnecker, of the NeuroCure Clinical Research Center, Charite University Medicine, Berlin, and colleagues enrolled 20 patients with relapsing-remitting MS and 14 healthy controls to undergo 7T MRI. A subgroup of 18 patients with MS also underwent 1.5T MRI.
“Against the background of the unresolved dispute over the clinical significance of black holes, and the increasing appreciation of gray matter pathology in MS, we investigated whether the visibility of T1 and T2 lesions in both gray and white matter would be influenced by the improved signal-to-noise ratio at 7T,” the authors wrote. “In particular, we hypothesized that the application of MPRAGE would facilitate the detection of hypointense lesions in comparison with conventional MRI.”
The 7T MPRAGE sequences detected a total number of 728 lesions, depicting more lesions than 7T FLASH (fast low-angle shot) and almost twice as much as 1.5T MPRAGE. Each of the 217 T1 hypointense lesions detected by the 7T MPRAGE sequences in the longitudinal subgroup persisted without major change in formation or size for at least one year and could thus be classified as a black hole, according to Sinnecker and colleagues.
Because the lesions did not change appearance over one year, the researchers suggested that they may express brain parenchymal destruction rather than temporary edema.
The researchers noted that the lesions were visualized with greater distinction concerning shape and appearance on the 7T MPRAGE images than via the 7T FLASH.
“To our knowledge, the present study is the first to demonstrate that, at ultrahigh-field strength, every T2 hyperintense lesion detected on T2-weighted FLASH sequences directly corresponds to a T1 hypointense lesion on a MPRAGE sequence,” the researchers concluded.
To read more about 7T MRI, read “7T MRI Sharpens its Focus”, in Health Imaging.