·LCModel軟件相關(guān)論文分享——磁共振頻譜數(shù)據(jù)定量后處理技術(shù)比較
LCModel 軟件是一款頻譜定量軟件。操作完全自動化，能直接輸出代謝物出的絕對濃度，兼容 Siemens, GE, Philips 等各大廠商和不同掃描序列（PRESS, STEAM等）的波譜數(shù)據(jù)。該軟件經(jīng)過18年的開發(fā)和全世界超過500家大型科研院所的試用，已逐漸成為事實上的波譜數(shù)據(jù)規(guī)范后處理平臺。HMRRC于2010年引進了LCModel并將利用該軟件對多種疾病，尤其是神經(jīng)精神疾病展開研究。
當(dāng)前LCModel的新版本為6.3，在該版本中，主要升級的內(nèi)容有：
1、用MEGA-PRESS估算GABA 。
2、改進了較弱代謝物的估計，特別是谷氨酰胺。
3、改進肌肉，脂質(zhì)，乳腺和肝臟光譜分析。
磁振造影 (MRI) 與磁振頻譜 (MRS) 具有非侵入性探測的特色，所以被廣泛地發(fā)展以應(yīng)用在臨床分析的研究上。
近年來隨著MRS應(yīng)用于臨床的例子增加，所以也發(fā)展出許多針對后處理的工具軟件，其中廣為人知的后處理軟件為LCModel。LCModel 是套被廣泛使用的磁振頻譜分析軟體。采用了圖形操作介面讓使用者對于磁振頻譜影像的分析達到方便以及簡潔的目的。LCMgui 是其在Linux系統(tǒng)中的圖形使用者介面，可以轉(zhuǎn)換多種磁振頻譜檔案格式到LCModel可處理的檔案格式。
特征
算法的小改進意味著結(jié)果會略有不同。
對光譜的分析主要是脂質(zhì)(以及水，可能是膽堿)，如脊椎、乳房和肝臟
肌譜分析
導(dǎo)入到電子表格程序的輸出文件
通用多通道(相控陣)檔案。
同時分析水信號的左邊和右邊
對脂質(zhì)和大分子信號的估計，特別是對腫瘤和病變的評估
交互式選擇和分析MRSI切片的矩形子集
Bruker、西門子公司和東芝的數(shù)據(jù)與LCMgui
多用戶安裝LCMgui
使用LCMgui中的擴展來歸檔文件
LCMgui用戶配置文件
使用LCMgui進行多個分析的批處理
選擇通用電氣LX(和更高)框架的子集
文件名過濾器在LCMgui文件選擇器中
更方便地處理非共振譜
模擬基礎(chǔ)光譜
對濃度比率施加“軟約束”
相干平均譜(如:從相控陣)
Features
Small improvements in the algorithms mean that the results will differ slightly.
Analysis of spectra with mainly lipid (and water plus possibly choline), as in vertebra,breast and liver.
Small improvements in the algorithms mean that the results will differ slightly.
Analysis of muscle spectra, particularly for IMCL.
Bruker ParaVision-3 files.
Output file for import to spreadsheet programs.
In multi-voxel analyses: combining PostScript files into one file; skipping over bad voxels.
GE multi-channel (phased-array) P-files.
Simultaneously analyzing a spectrum left & right of the water signal.
Estimation of lipid and macromolecule signals, especially for tumors and lesions.
Interactive selection and analysis of rectangular subsets of MRSI slices.
Bruker, Siemens syngo and Toshiba data with LCMgui.
Multi-User installations of LCMgui.
Archiving files using extensions in LCMgui.
LCMgui user profiles, e.g., for 1.5T & 3T data or Siemens & GE data on the same user account.
Batch processing of multiple analyses with LCMgui).
Selecting a subset of GE LX (and higher) frames, e.g., to eliminate bad frames due to patient motion.
Filename filters in the LCMgui File Selector.
More convenient handling of off-resonance spectra.
Simulating your own basis spectra.
Imposing "soft constraints" on concentration ratios.
Coherent averaging of spectra (e.g., from phased arrays).
Going back toward the old Version 5, e.g., for improved (but not perfect) consistency in large longitudinal studies.
The normal usage is to supply the time-domain data as a simple text file to LCModel. A possible alternative is the LCMgui graphical user interface:
Freely available for use with LCModel.
Simplified usage, often only with mouse clicks, in two steps:
1.Select the data with the File Selector;
2.Start LCModel (optionally checking and modifying any settings) in the Control Window.
Currently for the following single-voxel data:
*Bruker ParaVision fid files (if necessary, converted by you to analog mode with Bruker's convdta).
*GE 5.x Probe raw P-files and spectrum G-files.
*GE Probe raw P-files, including (new) Signa 22 P-files. Also for P-files with multi-channel (phased-array) data.
*Hitachi data: part of the Hitachi software; no need to purchase separately.
*Philips SDAT & SPAR files.
*Picker (later Marconi, now Philips) DUMP files.
*Siemens *rda files transferred from the syngo PC console and Siemens raw files from the (old) Numaris-3 Unix console.
*Toshiba rawData files and Version 7.xx (and later) DICOM files;
*Varian/Agilent fid files;
*Other data types using your own conversion script.
Currently for the following MRSI data:
*Philips, Siemens & Toshiba data, including interactive display, selection and analysis of full 2D slices or rectangular subsets. (Instructions in Sec. 3.7 of the LCModel Manual.)
*Other data types using your own conversion script;
*For GE MRSI (and single-voxel) data, Mary McLean's LCModel interface [MA McLean et al, Magn Reson Med 44, 401 (2000)] is integrated into GE's SAGE Research version (from SAGE Dev2002.1).
軟件操作系統(tǒng)要求:
A Linux PC with an AMD or Intel processor(s) (including x86-64). No Microsoft or Apple versions are planned.
You must be able to print or display PostScript files (or convert PostScript, e.g., to PDF with Adobe Acrobat Distiller).
An X-windows display. (This is checked for you in Step 2 of the test run below.)
A monitor with reasonable resolution (at least 1024 x 768).
You log on under your normal username (not root);
And you can at any time completely remove your installed package (including all output from the tests) with the command: $HOME/.uninstall-lcmodel
計算機硬件要求：
An LCModel analysis makes full use of one processor's speed and CPU cache memory. It makes no use of multiple processors (unless several analyses run simultaneously).
There is very little input/output or demands on graphics, memory or disk storage.
512 MB of memory should be sufficient, at least for a single user.
LCModel should run with almost any Linux distribution from 2001 or later. Most popular are Ubuntu, Red Hat & CentOS.
You should check all of this on your own computer with the free download and test runs. | 
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