Anonymous
Anonymous asked in 社會與文化語言 · 1 decade ago

關於MRI的東西 誰能幫我解釋名詞一下..

point-resolved spectroscopy sequence 是MRI的什麼東西 用來做什麼的 誰能幫我解釋一下嗎 謝謝.. .

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  • 立屏
    Lv 6
    1 decade ago
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    Point Resolved Spectroscopy(PRESS) 定點分辨波譜法

    point-resolved spectroscopy sequence 定點分辨波譜序列

    Point resolved spectroscopy is a multi echo single shot technique to obtain spectral data. PRESS is a 90-180-180 (slice selective pulses) sequence. The 90 radio frequency pulse rotates the spins in the yx-plane, followed by the first 180 pulse (spin rotation in the xz-plane) and the second 180 pulse (spin rotation in the xy-plane), which gives the signal.

    定點分辨波譜法(PRESS)是一種以單擊多迴來取得波譜回應資料的方式。PRESS是以90度-180度-180度(以切片來選用脈衝)的序列。

    90度角的無線電頻率是依yx平面自旋旋轉,接著是第一個180度脈衝(依xz平面自旋旋轉)以及第二個180度脈衝(依xy平面自旋旋轉),這樣才產生信號。

    With the long echo times used in PRESS, there is a better visualization of metabolites with longer relaxation times. Many of the metabolites depicted by stimulated echo technique are not seen on point resolved spectroscopy, but PRESS is less susceptible to motion, diffusion, and quantum effects and has a better SNR than stimulated echo acquisition mode (STEAM).

    因為PRESS需要用到的回音時間太長,對於較長回覆時間的新陳代謝對象有著更好的視覺化效果。許多激勵回波採樣模式(STREAM)下刻劃的出的新陳代謝物都無法在PRESS下顯影,但是PRESS不大容易受到動作、散射以及量子效應的影響,而且比激勵回波採樣模式有著較佳的信號噪音比(SNR)。

    老貓

    PS:小姐,這裡只是翻譯阿!下次能不能自己去找材料,作點功課...

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