Contributions
Abstract: P522
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 21 Imaging
Background: Magnetic resonance imaging (MRI) signal relaxometry seems sensitive to tissue damage in multiple sclerosis (MS). Increased T1 relaxation times have been related to water content while decreased T2* times have been associated to myelin content in normal-appearing white matter (NAWM) and lesions. However, long acquisition times for multiple-parameter quantification so far prevented the integration of these measurements into clinical scan protocols.
Aim: We sought to evaluate the use of fast simultaneous whole brain T1 and T2* quantification based on magnetic resonance fingerprinting (MRF) and to explore the changes in relaxation parameters in patients with MS.
Methods: MRF-EPI was used to acquire 33 axial slices with a resolution of 1.1x1.1x3 mm3. T1 and T2* maps were calculated by matching the fingerprints with a precomputed dictionary. The measurement was performed in 5 MS patients (2 men, 37.6±12.3 years) and 4 healthy volunteers (HV) (2 men, 31.8±5.2 years). In patients, lesions were manually segmented in 3D-Magnetization Prepared Rapid Gradient-Echo and post contrast T1-spin echo images. Grey matter (GM) and NAWM segmentations were obtained by SIENAX and applied to the MRF images in order to calculate the average T1 and T2* of each compartment.
Results: Whole brain MRF was successfully obtained in all the participants within an acquisition time of 15 minutes. Average T1/T2* values in patients were 1353±236 / 45±12ms in GM and 1207±223 / 48±11ms in NAWM. No significant difference was found in those values compared with HVs, with a tendency to higher variability in NAWM relaxation times in the patients. White matter lesions were clearly visible in T1 and T2* maps. T1 values in lesions (1147±178ms) were lower than in NAWM (p=0.002) while T2* values were higher in lesions (56±9ms) than in NAWM (p=0.005). In one patient two contrast enhancing lesions were detected in T1-spin echo sequence in the brainstem; those lesions had T1/ T2*values of 1404±214 / 42±9 ms in MRF sequence.
Conclusions: Whole brain MRF acquisition is feasible and displays decreased T1 and increased T2* relaxation times in MS lesions, suggesting improved tissue damage characterization. Further, preliminary data indicates that new lesions which enhance with contrast in conventional sequences may have particular behaviour in MRF. Future studies combining MRF with advanced MRI or pathology data could help understanding the underlying pathophysiology mechanisms.
Disclosure:
BR, EMH, JP and SW declare nothing to disclose.
ES received travel reimbursement from TEVA.
SL received speaker honoraria from Biogen Idec, Novartis, Teva, Genzyme and Merck, and research support from a Juan Rodes grant from the Instituto de Salud Carlos III (JR14/00016) and the Spanish Government (PI15/00587).
NSV receives funding from the Spanish Government (Instituto de Salud Carlos III, Spain and Fondo Europeo de Desarrollo Regional (FEDER, FI16/00251), and a Predoctoral Grant for Health Research.
MS received speaker honoraria from Genzyme and Novartis, and funding from the Generalitat de Catalunya (SLT002/16/00354).
YB received speaking honoraria from Biogen, Novartis and Genzyme.
AS received compensation for consulting services and speaker honoraria from Bayer-Schering, Merck-Serono, Biogen-Idec, Sanofi-Aventis, TEVA and Novartis, and funding from the Spanish Government (PI15/00587, RD16/0015/0002, RD16/0015/0003, RD12/0032/0002, RD12/0060/01-02).
Funding: This work was funded by a Proyecto de Investigacion en Salud (FIS 2015. PI15/00587, SL, AS) integrated in the Plan Estatal de Investigación Científica y Técnica de Innovación I+D+I and co-funded by the Instituto de Salud Carlos III-Subdirección General de Evaluación and the Fondo Europeo de Desarrollo Regional (FEDER, 'Otra manera de hacer Europa'); Red Española de Esclerosis Múltiple (REEM) (RD16/0015/0002, RD16/0015/0003, RD12/0032/0002, RD12/0060/01-02).
Abstract: P522
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 21 Imaging
Background: Magnetic resonance imaging (MRI) signal relaxometry seems sensitive to tissue damage in multiple sclerosis (MS). Increased T1 relaxation times have been related to water content while decreased T2* times have been associated to myelin content in normal-appearing white matter (NAWM) and lesions. However, long acquisition times for multiple-parameter quantification so far prevented the integration of these measurements into clinical scan protocols.
Aim: We sought to evaluate the use of fast simultaneous whole brain T1 and T2* quantification based on magnetic resonance fingerprinting (MRF) and to explore the changes in relaxation parameters in patients with MS.
Methods: MRF-EPI was used to acquire 33 axial slices with a resolution of 1.1x1.1x3 mm3. T1 and T2* maps were calculated by matching the fingerprints with a precomputed dictionary. The measurement was performed in 5 MS patients (2 men, 37.6±12.3 years) and 4 healthy volunteers (HV) (2 men, 31.8±5.2 years). In patients, lesions were manually segmented in 3D-Magnetization Prepared Rapid Gradient-Echo and post contrast T1-spin echo images. Grey matter (GM) and NAWM segmentations were obtained by SIENAX and applied to the MRF images in order to calculate the average T1 and T2* of each compartment.
Results: Whole brain MRF was successfully obtained in all the participants within an acquisition time of 15 minutes. Average T1/T2* values in patients were 1353±236 / 45±12ms in GM and 1207±223 / 48±11ms in NAWM. No significant difference was found in those values compared with HVs, with a tendency to higher variability in NAWM relaxation times in the patients. White matter lesions were clearly visible in T1 and T2* maps. T1 values in lesions (1147±178ms) were lower than in NAWM (p=0.002) while T2* values were higher in lesions (56±9ms) than in NAWM (p=0.005). In one patient two contrast enhancing lesions were detected in T1-spin echo sequence in the brainstem; those lesions had T1/ T2*values of 1404±214 / 42±9 ms in MRF sequence.
Conclusions: Whole brain MRF acquisition is feasible and displays decreased T1 and increased T2* relaxation times in MS lesions, suggesting improved tissue damage characterization. Further, preliminary data indicates that new lesions which enhance with contrast in conventional sequences may have particular behaviour in MRF. Future studies combining MRF with advanced MRI or pathology data could help understanding the underlying pathophysiology mechanisms.
Disclosure:
BR, EMH, JP and SW declare nothing to disclose.
ES received travel reimbursement from TEVA.
SL received speaker honoraria from Biogen Idec, Novartis, Teva, Genzyme and Merck, and research support from a Juan Rodes grant from the Instituto de Salud Carlos III (JR14/00016) and the Spanish Government (PI15/00587).
NSV receives funding from the Spanish Government (Instituto de Salud Carlos III, Spain and Fondo Europeo de Desarrollo Regional (FEDER, FI16/00251), and a Predoctoral Grant for Health Research.
MS received speaker honoraria from Genzyme and Novartis, and funding from the Generalitat de Catalunya (SLT002/16/00354).
YB received speaking honoraria from Biogen, Novartis and Genzyme.
AS received compensation for consulting services and speaker honoraria from Bayer-Schering, Merck-Serono, Biogen-Idec, Sanofi-Aventis, TEVA and Novartis, and funding from the Spanish Government (PI15/00587, RD16/0015/0002, RD16/0015/0003, RD12/0032/0002, RD12/0060/01-02).
Funding: This work was funded by a Proyecto de Investigacion en Salud (FIS 2015. PI15/00587, SL, AS) integrated in the Plan Estatal de Investigación Científica y Técnica de Innovación I+D+I and co-funded by the Instituto de Salud Carlos III-Subdirección General de Evaluación and the Fondo Europeo de Desarrollo Regional (FEDER, 'Otra manera de hacer Europa'); Red Española de Esclerosis Múltiple (REEM) (RD16/0015/0002, RD16/0015/0003, RD12/0032/0002, RD12/0060/01-02).