MR Imaging of the Brain with a T1-Weighted Fluid-Attenuated Inversion Recovery Sequence: Comparison with Conventional T1-Weighted Spin Echo Sequence

以T1FLAIR及T1SE兩種不同脈衝序列所得的腦部影像比較

鄭碩仁(Sho-Jen Cheng) ； 范揚凱(Yang-Kai Fan) ； 黃榮貴(Jon-Kway Huang)

《中華放射線醫學雜誌》 30卷3期 (2005/06) Pp. 139-145

摘要

傳統自旋回轉脈衝序列所得的T1影像已廣泛用來呈現腦的相關解剖位置，但灰白質及病灶的對比度常常不足，以致病灶在腦的相關解剖位置無法清楚定位。以液體衰減反轉回復脈衝序列來取像，可增強灰白質及病灶的對比度，進而幫助偵測病灶，但取像時間過長是其致命傷。若嘗試以T1液體衰減反轉回復(T1FLAIR)脈衝序列來取像，可在與傳統磁自旋回訊(spin echo)脈衝序列所得的T1影像相近的時間內取得較佳對比度的T1影像。
T1FLAIR脈衝序列是運用快速反轉回復(fast inversion recover)脈衝序列，以反轉回復(inversion recovery)脈衝做取像前準備，再以快速磁自旋回訊(fast spin echo)的方式取得訊號組像。共有99位受檢者在同一次檢查同時取得T1液體衰減反轉回復脈衝序列及T1磁自旋回訊脈衝序列的T1影像，以灰白質、脊髓液及病灶的對比、對比度做量化比較。
以T1液體衰減反轉回復脈衝序列取得的T1影像確實比以T1磁自旋回訊脈衝序列取得的T1影像呈現較佳的灰白質的對比度及灰白質對病灶的對比度，尤其針對白質內的病灶史可清楚定位。
以T1液體衰減反轉回復脈衝序列取像，可增強灰白質及病灶的對比度，進而界定清楚病灶侵犯範圍及因病灶引起的水腫。相對於以傳統磁自旋回訊脈衝序列所得的T1影像，可提供更多的資訊。

關鍵字

腦部，磁振造影 ； 磁振造影，比較研究 ； 磁振造影反轉回復

並列摘要

Ti-weighted spin-echo (T1SE) images are widely used as a standard sequence to study the anatomy of the brain. They may demonstrate signal changes characteristic of certain pathologic abnormalities. However, the image contrast is not sufficient to differentiate white from gray matter and to delineate most pathologic lesions. We tried to improve lesion conspicuity with comparable acquisition time with T1-weighted fluid-attenuated inversion recovery (T1FLAIR) sequence.
T1-weighted fluid-attenuated inversion recovery (T1FLAIR) sequence is the fast inversion recovery (FLAIR) sequence coupled an inversion recovery (IR) preparation pulse and a fast spin echo (FSE) readout with interleaved data acquisition. Ninety-nine patients underwent T1SE and T1FLAIR during the same imaging session. The following features on T1-weighted images performed using T1FLAIR and T1SE sequences were compared quantitatively: individual signal intensity of gray matter, white matter, CFS, lesion, edema and noise; white matter-gray matter contrast (SI(subscript white matter)-SI(subscript gray matter)), white matter-gray matter contrast-to-noise ratio (CNR) (SI(subscript white matter)-SI(subscript gray matter)/noise) and contrast ratio (SI(subscript white matter)-SI(subscript gray matter)/SI(subscript white matter)); white matter-CSF contrast. CNR and contrast ratio: white matter-lesion contrast, CNR, and contrast ratio; lesion-CSF contrast, CNR and contrast ratio; white matter-edema contrast, CNR and contrast ratio.
T1FLAIR yielded better gray matter-white matter contrast and white matter-CSF contrast and CNR than T1SE did. Lesion conspicuity on T1FLAIR was also superior to that on T1SE, especially within the white matter.
T1FLAIR can provide superior gray-white matter contrast and improve lesion conspicuity with comparable acquisition time.

並列關鍵字

Brain, MR ； MR, comparative studies ； MR, inversion recovery