Contributions
Abstract: P1110
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - MRI and PET
Background: Various 3T and 7T single MRI contrasts have been assessed regarding their ability to detect and classify cortical lesions (CL), with 7T MRI generally showing markedly better sensitivity. However, the use of multiple MRI contrasts has also improved CL detection over single-contrast reads at 3T, and may provide results closer to those from 7T assessments.
Objective: To compare multi-contrast CL reading protocols on 3T and 7T MRI.
Methods: 20 MS patients (10 RRMS, 10 SPMS) were imaged with 3T and 7T MRI. 3T scans included 3D T1-weighted (MP2RAGE), 3D FLAIR, dual proton-density/T2-weighted, and 3D magnetization-transfer (MT) contrasts. 7T scans included 3D T1-weighted (MP2RAGE), and 2D-T2*-weighted contrasts. Images were registered into a common space and lesions were segmented and classified by a single rater (JM). Wilcoxon-signed-rank-test was used to assess CL counts, and a mixed effect model to assess MT ratio (MTR) values.
Results: 720 CL were detected using the 7T multi-contrast protocol: median 24.5, range 0-119. 420 (58%) were leukocortical (LCL), 27 (4%) were intracortical (ICL) and 273 (38%) were subpial (SPL).
424 CL were detected using the 3T multi-contrast protocol (limiting assessment to the coverage of the 7T T2* scan): median 13, range 1-59: 393 (93%) LCL, 0 ICL, 31(7%) SPL. The 3T Total CL, ICL and SPL counts were significantly lower than the 7T counts (p< 0.002). The LCL count was not significantly different between 3T and 7T.
126 (30%) LCL were detected only on 3T MRI and missed on 7T due to the relatively low signal on the T2*-weighted images.
31 (11%) SPL were detected on both 3T and 7T MRI.
LCL visible on both 3T and 7T (common LCL) had significantly lower MTR (p< 0.0001) than LCL visible only on 3T (7T-negative LCL).
MTR of SPL visible on both 3T and 7T (common SPL) did not differ significantly from MTR of SPL visible only on 7T (3T-negative SPL).
Conclusion: Multi-contrast 3T MRI is comparable to 7T MRI in the estimation of LCL, and has the advantage of better coverage of the whole brain. 7T MRI is superior for ICL and SPL assessment.
MTR was significantly lower in common LCL vs 7T-negative LCL, suggesting that lower contrast on 7T T2*-weighted MRI relates to less demyelination in LCL. Conversely, the finding that MTR in 3T-negative SPL did not differ from MTR in SPL visible at both 3T and 7T suggests that detectability of subpial lesions depends more on MRI resolution and T2-weighted contrast in the cortex.
Disclosure: Josefina Maranzano: no disclosures
Mahsa Dadar: no disclosures
David A. Rudko was supported by an endMS Postdoctoral Fellowship from the Multiple Sclerosis Society of Canada
Joe Gati: no disclosures
Ravi Menon: no disclosures
Sarah A. Morrow has served on advisory boards for Biogen Idec, EMD Serono, Genzyme Canada, Novartis and Roche. She has received Investigator Initiated Grant Funds from Genzyme Canada and acted as site PI for multi-center trials funded by Novartis, Genzyme, Roche
Marcelo Kremenchutzky serves as Chapman Chair in MS and Clinical Research at lHSC but other wise has nothing to disclose
D. Louis Collins: no disclosures
Dougla Arnold reports consultant fees and/or grants from Acorda, Adelphi, Alkermes, Biogen, Celgene, Frequency Therapeutics, Genentech, Genzyme, Hoffman LaRoche, Immune Tolerance Network, Immunotec, MedDay Merck-Serono, Novartis, Pfizer, Receptos, Roche, Sanofi-Aventis, Canadian Institutes of Health Research, MS Society of Canada, International Progressive MS Alliance, and an equity interest in NeuroRx Research
Sridar Narayanan reports personal fees from NeuroRx Research and a speaker´s honorarium from Novartis Canada, unrelated to the submitted work
Abstract: P1110
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - MRI and PET
Background: Various 3T and 7T single MRI contrasts have been assessed regarding their ability to detect and classify cortical lesions (CL), with 7T MRI generally showing markedly better sensitivity. However, the use of multiple MRI contrasts has also improved CL detection over single-contrast reads at 3T, and may provide results closer to those from 7T assessments.
Objective: To compare multi-contrast CL reading protocols on 3T and 7T MRI.
Methods: 20 MS patients (10 RRMS, 10 SPMS) were imaged with 3T and 7T MRI. 3T scans included 3D T1-weighted (MP2RAGE), 3D FLAIR, dual proton-density/T2-weighted, and 3D magnetization-transfer (MT) contrasts. 7T scans included 3D T1-weighted (MP2RAGE), and 2D-T2*-weighted contrasts. Images were registered into a common space and lesions were segmented and classified by a single rater (JM). Wilcoxon-signed-rank-test was used to assess CL counts, and a mixed effect model to assess MT ratio (MTR) values.
Results: 720 CL were detected using the 7T multi-contrast protocol: median 24.5, range 0-119. 420 (58%) were leukocortical (LCL), 27 (4%) were intracortical (ICL) and 273 (38%) were subpial (SPL).
424 CL were detected using the 3T multi-contrast protocol (limiting assessment to the coverage of the 7T T2* scan): median 13, range 1-59: 393 (93%) LCL, 0 ICL, 31(7%) SPL. The 3T Total CL, ICL and SPL counts were significantly lower than the 7T counts (p< 0.002). The LCL count was not significantly different between 3T and 7T.
126 (30%) LCL were detected only on 3T MRI and missed on 7T due to the relatively low signal on the T2*-weighted images.
31 (11%) SPL were detected on both 3T and 7T MRI.
LCL visible on both 3T and 7T (common LCL) had significantly lower MTR (p< 0.0001) than LCL visible only on 3T (7T-negative LCL).
MTR of SPL visible on both 3T and 7T (common SPL) did not differ significantly from MTR of SPL visible only on 7T (3T-negative SPL).
Conclusion: Multi-contrast 3T MRI is comparable to 7T MRI in the estimation of LCL, and has the advantage of better coverage of the whole brain. 7T MRI is superior for ICL and SPL assessment.
MTR was significantly lower in common LCL vs 7T-negative LCL, suggesting that lower contrast on 7T T2*-weighted MRI relates to less demyelination in LCL. Conversely, the finding that MTR in 3T-negative SPL did not differ from MTR in SPL visible at both 3T and 7T suggests that detectability of subpial lesions depends more on MRI resolution and T2-weighted contrast in the cortex.
Disclosure: Josefina Maranzano: no disclosures
Mahsa Dadar: no disclosures
David A. Rudko was supported by an endMS Postdoctoral Fellowship from the Multiple Sclerosis Society of Canada
Joe Gati: no disclosures
Ravi Menon: no disclosures
Sarah A. Morrow has served on advisory boards for Biogen Idec, EMD Serono, Genzyme Canada, Novartis and Roche. She has received Investigator Initiated Grant Funds from Genzyme Canada and acted as site PI for multi-center trials funded by Novartis, Genzyme, Roche
Marcelo Kremenchutzky serves as Chapman Chair in MS and Clinical Research at lHSC but other wise has nothing to disclose
D. Louis Collins: no disclosures
Dougla Arnold reports consultant fees and/or grants from Acorda, Adelphi, Alkermes, Biogen, Celgene, Frequency Therapeutics, Genentech, Genzyme, Hoffman LaRoche, Immune Tolerance Network, Immunotec, MedDay Merck-Serono, Novartis, Pfizer, Receptos, Roche, Sanofi-Aventis, Canadian Institutes of Health Research, MS Society of Canada, International Progressive MS Alliance, and an equity interest in NeuroRx Research
Sridar Narayanan reports personal fees from NeuroRx Research and a speaker´s honorarium from Novartis Canada, unrelated to the submitted work