增强FLAIR成像在听神经瘤诊断和鉴别诊断中的价值

目的通过与增强T1WI及脑桥小脑角区（CPA）脑膜瘤的比较研究,探讨增强FLAIR在听神经瘤的诊断和鉴别诊断中的价值。方法17例听神经瘤患者行增强前后T1WI和FLAIR成像,比较两序列增强图像上肿瘤边界、显著性、强化的内听道内肿瘤部分的显示、肿瘤范围、肿瘤与白质的对比率（CR）和对比噪声比（CNR）;同一时期CPA脑膜瘤6例,观察并比较其与听神经瘤在T1WI、FLAIR增强前后图像上的信号强度和强化程度。结果增强FLAIR上听神经瘤的边界、肿瘤显著性优于增强T1WI或与其相似,3例肿瘤的最上部和/或最下部仅在增强FLAIR上显示;在15例具有强化的内听道内肿瘤部分中2例在增强FLAIR上更明显,6例在增强T1WI上更明显,7例在两序列上相似。增强FLAIR上肿瘤与脑白质的CR和CNR均明显高于增强T1WI。脑膜瘤和听神经瘤在平扫T1WI及FLAIR图像上信号强度重叠明显,两肿瘤在增强FLAIR上信号强度及强化程度差异明显,而在增强T1WI上无差异。结论增强FLAIR在听神经瘤的诊断中具有重要价值,并可对其与脑膜瘤作出准确区分。

Diagnosis and differential diagnosis of contrast-enhanced fluid-attenuated inversion-recovery MR imaging in acoustic neuroma

Objective To determine the clinical value of contrast-enhanced FLAIR imaging of acoustic neuroma by comparing results with contrast-enhanced T1WI and meningioma located in cerebellopontine angle (CPA). Methods Seventeen patients with acoustic neuroma underwent FLAIR and spin-echo T1WI with and without intravenous gadopentetate dimeglumine. Contrast-enhanced FLAIR and T1WI images were compared for boundary, conspicuity, enhancing intracanalicular tumor parts, scope of tumors, and contrast ratio and contrast-to-noise ratio (CNR) of tumor-to-white matter. Acoustic neuroma and 6 CPA meningioma were compared for signal intensity and signal increase degree of tumors on FLAIR and T1WI images. Results Compared with contrast-enhanced T1WI images, the boundary and conspicuity of acoustic neuroma were superior or equal on contrast-enhanced FLAIR images, superior and/or inferior parts of tumors were only displayed on contrast-enhanced FLAIR images in three cases. Among 15 enhancing intracanalicular tumor parts, contrast-enhanced FLAIR images were superior in 2 cases, equal in 7 cases, and inferior in 6 cases. The tumor-to-white matter CR and CNR were higher on contrast-enhanced FLAIR images than on contrast-enhanced T1WI images. The signal intensity range of acoustic neuroma and meningioma had obvious overlap on both pre-enhanced T1WI and FLAIR images; the signal intensity and signal increase degree had no difference between two groups on contrast-enhanced T1WI images, but the difference was significant on contrast-enhanced FLAIR images. Conclusion Contrast-enhanced FLAIR imaging has important value in evaluating acoustic neuroma, and can discriminate it with meningioma.