Contributions
Abstract: P492
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - Imaging
Background: Increased paramagnetic susceptibility in Multiple Sclerosis (MS) lesions occurs in roughly one-third of MS lesions. This is believed to be due to one or more of the following factors: increased iron content in macrophages, reduction in diamagnetism due to loss of myelin, presence of blood products and changes in perfusion. This work aims to quantitatively assess changes in susceptibility in lesions over time using quantitative susceptibility mapping (QSM).
Methods: The study included 50 MS patients (40 RRMS, 8 SPMS, 2 PPMS: 19 male, 31 female) aged 45.8+/-11 years. Patients were imaged at baseline and 2 years later with susceptibility weighted imaging (SWI) and conventional MRI at 3T. Disease duration was 12.8+/-9 years and Expanded Disability Status Scale (EDSS) was 3.0+/-2 for baseline and 3.1+/-2 for follow-up. Iron-laden lesions were identified in the QSM images and then compared to T1WI and T2 FLAIR. Iron lesions were classified as:
(1) stable between scans,
(2) absent from baseline and present in follow-up,
(3) present in baseline but shrinking in follow-up,
(4) present in baseline but absent in follow-up, or
(5) growing between baseline and follow-up. Count, volume and susceptibility of the lesions were estimated and its association with EDSS was assessed.
Results: Iron-laden lesions were present in 31 subjects (62%) with a total of 107 QSM lesions. The susceptibilities at baseline and follow up for the different categories of lesions were: (1) 82 lesions with 48.6+/-18.2ppb and 43.9+/-21ppb; (2) 4 lesions with 21.1+/-3.2ppb and 45+/-16.2ppb; (3) 9 lesions with 46.6+/-20.8ppb and 27.9+/-13.6ppb; (4) 9 lesions with 32.1+/-15.1ppb and 10.5+/-9.4ppb; (5) 1 lesion with 59.4ppb and 57.5ppb. In 2 QSM lesions no corresponding signal was seen in T1 or T2 FLAIR, their susceptibilities were 19.9+/-9.3ppb and 10.2+/-4.7ppb respectively. EDSS was not associated with the presence or change in QSM detected lesion (p>0.05).
Conclusions: SWI and QSM both provide a means to visualize iron-laden lesions and quantitatively assess susceptibility changes longitudinally. Many of the lesions had susceptibilities comparable to gray matter (~50ppb) suggesting local demyelination. Not all QSM lesions were associated with signal changes on T1 or FLAIR images and thus susceptibility changes may potentially represent a more sensitive index of the underlying pathophysiological process that warrants further investigation.
Disclosure:
Karthikeyan Subramanian: Full time employee of MR Innovations Inc.
David Utriainen: Full time employee of MR Innovations Inc.
Deepa P Ramasamy: Nothing to disclose.
John Beaver: Full time employee of AbbVie. This research was sponsored by AbbVie. Participated in the design, interpretation of data, preparation, and approval of the publication.
Sean Sethi: Full time employee of MR Innovations Inc.
Ferdinand Schweser: Nothing to disclose
Miller Fawaz: Full time employee of MR Innovations Inc.
Jesper Hagemeier: Nothing to disclose.
Rajasimhan Rajagovindan: Full time employee of AbbVie. This research was sponsored by AbbVie. Participated in the design, interpretation of data, preparation, and approval of the publication.
Robert Zivadinov: Received personal compensation from Teva Pharmaceuticals, Biogen Idec, EMD Serono, Genzyme-Sanofi, Claret Medical, IMS Health and Novartis for speaking and consultant fees. He received financial support for research activities from Teva Pharmaceuticals, Genzyme-Sanofi, Novartis, Claret Medical, Intekrin and IMS Health.
Ewart Mark Haacke: President of MR Innovations, research support was provided by AbbVie.
Abstract: P492
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - Imaging
Background: Increased paramagnetic susceptibility in Multiple Sclerosis (MS) lesions occurs in roughly one-third of MS lesions. This is believed to be due to one or more of the following factors: increased iron content in macrophages, reduction in diamagnetism due to loss of myelin, presence of blood products and changes in perfusion. This work aims to quantitatively assess changes in susceptibility in lesions over time using quantitative susceptibility mapping (QSM).
Methods: The study included 50 MS patients (40 RRMS, 8 SPMS, 2 PPMS: 19 male, 31 female) aged 45.8+/-11 years. Patients were imaged at baseline and 2 years later with susceptibility weighted imaging (SWI) and conventional MRI at 3T. Disease duration was 12.8+/-9 years and Expanded Disability Status Scale (EDSS) was 3.0+/-2 for baseline and 3.1+/-2 for follow-up. Iron-laden lesions were identified in the QSM images and then compared to T1WI and T2 FLAIR. Iron lesions were classified as:
(1) stable between scans,
(2) absent from baseline and present in follow-up,
(3) present in baseline but shrinking in follow-up,
(4) present in baseline but absent in follow-up, or
(5) growing between baseline and follow-up. Count, volume and susceptibility of the lesions were estimated and its association with EDSS was assessed.
Results: Iron-laden lesions were present in 31 subjects (62%) with a total of 107 QSM lesions. The susceptibilities at baseline and follow up for the different categories of lesions were: (1) 82 lesions with 48.6+/-18.2ppb and 43.9+/-21ppb; (2) 4 lesions with 21.1+/-3.2ppb and 45+/-16.2ppb; (3) 9 lesions with 46.6+/-20.8ppb and 27.9+/-13.6ppb; (4) 9 lesions with 32.1+/-15.1ppb and 10.5+/-9.4ppb; (5) 1 lesion with 59.4ppb and 57.5ppb. In 2 QSM lesions no corresponding signal was seen in T1 or T2 FLAIR, their susceptibilities were 19.9+/-9.3ppb and 10.2+/-4.7ppb respectively. EDSS was not associated with the presence or change in QSM detected lesion (p>0.05).
Conclusions: SWI and QSM both provide a means to visualize iron-laden lesions and quantitatively assess susceptibility changes longitudinally. Many of the lesions had susceptibilities comparable to gray matter (~50ppb) suggesting local demyelination. Not all QSM lesions were associated with signal changes on T1 or FLAIR images and thus susceptibility changes may potentially represent a more sensitive index of the underlying pathophysiological process that warrants further investigation.
Disclosure:
Karthikeyan Subramanian: Full time employee of MR Innovations Inc.
David Utriainen: Full time employee of MR Innovations Inc.
Deepa P Ramasamy: Nothing to disclose.
John Beaver: Full time employee of AbbVie. This research was sponsored by AbbVie. Participated in the design, interpretation of data, preparation, and approval of the publication.
Sean Sethi: Full time employee of MR Innovations Inc.
Ferdinand Schweser: Nothing to disclose
Miller Fawaz: Full time employee of MR Innovations Inc.
Jesper Hagemeier: Nothing to disclose.
Rajasimhan Rajagovindan: Full time employee of AbbVie. This research was sponsored by AbbVie. Participated in the design, interpretation of data, preparation, and approval of the publication.
Robert Zivadinov: Received personal compensation from Teva Pharmaceuticals, Biogen Idec, EMD Serono, Genzyme-Sanofi, Claret Medical, IMS Health and Novartis for speaking and consultant fees. He received financial support for research activities from Teva Pharmaceuticals, Genzyme-Sanofi, Novartis, Claret Medical, Intekrin and IMS Health.
Ewart Mark Haacke: President of MR Innovations, research support was provided by AbbVie.