乳腺磁共振成像扫描序列及扫描方位的选择

目的 探讨常规SE序列、FSE序列和3D-FSEGR序列及不同扫描方位在乳腺病变MRI诊断中作用。方法 40例乳腺肿块性病变常规SE序列T1WI及脂肪抑制FSE序列T2WI分别行轴位及矢状位平扫。注射Gd-DTPA后采用3D-FSPGR序列行矢状位动态增强扫描．之后再采用SE序列行脂肪抑制T1WI轴位、矢状位和(或)冠状位扫描。结果 3种扫描序列均有较高的信噪比及较高的病变与正常组织对比分辨率。SE序列T1WI平扫信噪比优，但病变与正常组织的对比分辨率不及FSE序列T2WI，而动态增强3D-FSPGR序列显示病变最敏感，可显示平扫不能显示或显示不明确的病变，且可根据病变的增强特点及时间-信号强度曲线进行定性诊断。增强后脂肪抑制SE序列T1WI显示病变亦较敏感，但不能行动态增强扫描。3种成像方位中，轴位与矢状位更利于显示病变及病变侵犯胸壁和腋窝淋巴结肿大。结论 动态增强3D-FSPGR是乳腺肿块病变中最有价值的检查序列。轴位与矢状位应作为乳腺检查中的基本位置。

Sequence and position: the selection in MRI of the breast

Objective To explore the impact of magnetic resonance imaging (MRI) for the breast lesions with spin echo(SE), fast spin echo (FSE), 3 dimension fast SPGR(SD-FSPGR) and multiple position. Methods Forty/cases with breast masses were scanned by means of SE T1-weighted imaging (T1WI) and FSE T2-weighted imaging(T2WI) with fat suppression in axial and sagittal position. After injecting Gd-DTPA, dynamic enhancement with 3D-FSPGR sequence was done in sagittal position. Then, SE T1WI with fat suppression was used in axial , sagittal and / or coronal position. Results All of 3 imaging sequences showed satisfied signal to noise ratio (SNR) and high contrast resolution between breast lesions and their surround normal tissue. SE T1WI without Gd-DTPA had higher SNR than FSE T2WI, but was not better than FSE T2WI in differentiated lesions from normal tissue. 3D-FSPGR sequence with chemical saturation had the highest sensitivity for detecting breast lesions among all 3 sequences and could show the occult lesions and increased the accuracy of diagnosis according to the enhanced characteristics and time intensity curves of lesions . Contrast enhanced fat-suppressed SE sequence also had high sensitivity, but was not used as dynamic enhanced scan. Axial and sagittal images were good for observing extent of the breast lesions and axillary enlarged lymph nodes. Conclusion 3D-FSPGR is a recommended and valuable sequence. Axial and sagittal MRI for breast lesions should be routine positions.