The role of edema and demyelination in chronic T1 black holes: A quantitative magnetization transfer study
✍ Scribed by Ives Levesque; John G. Sled; Sridar Narayanan; A. Carlos Santos; Steven D. Brass; Simon J. Francis; Douglas L. Arnold; G. Bruce Pike
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 146 KB
- Volume
- 21
- Category
- Article
- ISSN
- 1053-1807
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✦ Synopsis
Abstract
Purpose
To use quantitative magnetization transfer imaging (qMTI) in an investigation of T~1~‐weighted hypointensity observed in clinical magnetic resonance imaging (MRI) scans of multiple sclerosis (MS) patients, which has previously been proposed as a more specific indicator of tissue damage than the more commonly detected T~2~ hyperintensity.
Materials and Methods
A cross‐sectional study of 10 MS patients was performed using qMTI. A total of 60 MTI measurements were collected in each patient at a resolution of 2 × 2 × 7 mm, over a range of saturation pulses. The observed T~1~ and T~2~ were also measured. qMT model parameters were estimated using a voxel‐by‐voxel fit.
Results
A total of 65 T~2~‐hyperintense lesions were identified; 53 were also T~1~ hypointense. In these black holes, the qMTI‐derived semisolid pool fraction F correlated negatively with T~1,obs~ (r^2^ = 0.76; P < 0.0001). The water pool absolute size (PD~f~) showed a weaker correlation with T~1,obs~ (positive, r^2^ = 0.53; P < 0.0001). The magnetization transfer ratio (MTR) showed a similarly strong correlation with F and a weaker correlation with PD~f~ (r^2^ = 0.18; P < 0.04).
Conclusion
T~1~ increases in chronic black holes strongly correlated with the decline in semisolid pool size, and somewhat less to the confounding effect of edema. MTR was less sensitive than T~1,obs~ to liquid pool changes associated with edema. J. Magn. Reson. Imaging 2005;21:103–110. © 2005 Wiley‐Liss, Inc.