Abstract：
:Quantitative MRI of neuromelanin (NM) containing structures (referred to as NM-MRI) in the brainstem, namely the locus coeruleus (LC) and substantia nigra (SN), may assist with the early detection of Parkinson's disease (PD) and Alzheimer's disease (AD) as well as differential diagnosis in the early disease stages. In this study, two gradient echo (GRE) sequences with magnetization transfer contrast (MTC) preparation pulses were developed to simultaneously image the LC and SN. This has been a challenge with NM-MRI techniques used in previous studies due to the relatively high specific absorption rate (SAR) induced by these techniques. In addition, a semi-automated quantitative analysis scheme was applied to estimate volumes and contrast-to-noise ratios (CNR) of the LC and SN based on segmentation of both structures. Compared to a T1-weighted turbo spin echo (TSE) sequence typically used for simultaneous imaging of the LC and SN, the two GRE-MTC sequences exhibited improved performance in terms of higher sensitivity (in CNR) in imaging the SN and lower SAR during the scans. A multiple-measurement protocol was adopted as well so that motion degraded measurements could be removed and artifacts associated with motion could be corrected. The present approach has demonstrated advantages in image acquisition (lower SAR and higher sensitivity), image pre-processing (with motion correction) and quantitative image analysis (segmentation-based estimation of volume and CNR) when compared with existing NM-MRI approaches. This approach has potential for detection and monitoring of neurodegeneration in LC and SN in disease states including AD and PD.
journal_name
Magn Reson Imagingjournal_title
Magnetic resonance imagingauthors
Chen X,Huddleston DE,Langley J,Ahn S,Barnum CJ,Factor SA,Levey AI,Hu Xdoi
10.1016/j.mri.2014.07.003subject
Has Abstractpub_date
2014-12-01 00:00:00pages
1301-6issue
10eissn
0730-725Xissn
1873-5894pii
S0730-725X(14)00206-9journal_volume
32pub_type
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