Baumgartner B R, Chezmar J L
Department of Radiology, Emory University School of Medicine, Atlanta, GA.
Semin Ultrasound CT MR. 1989 Feb;10(1):43-62.
A simple renal cyst will have low signal intensity on T1-weighted SE images with short TE and short TR because of the long T1 values of the cyst fluid. With increasing TE and TR, cysts demonstrate increased signal intensity due to the long T2 values of the cyst fluid. On T1-weighted images a complicated cyst will have higher signal intensity than a simple cyst; it may not be possible to differentiate these complicated cysts from solid masses. MRI seems to be useful in identifying simple cyst fluid and, therefore, has potential in characterization of cystic lesions considered complex by CT or ultrasound. Unfortunately, imaging techniques have not yet been optimized, diagnostic criteria are somewhat vague, and accuracy has not been established in a representative patient population. Solid masses often can be identified and differentiated from simple, uncomplicated cysts on MR images. The inability to differentiate among various types of solid tumors or to separate these from complicated cysts or inflammatory masses remains a limitation. Most lesions are more readily seen on contrast-enhanced CT than on MR images and therefore the role of MRI in the detection and diagnosis of renal cell carcinoma remains limited. Although the high detection rate of renal cell carcinoma is encouraging, CT is still more sensitive than MR in demonstrating solid lesions less than 3 cm in diameter. MRI cannot be used as a screening modality for renal tumors. MRI seems quite helpful in the staging of renal cell carcinoma. Macroscopic extension into the perinephric fat, tumor extension into the renal vein and the inferior vena cava, and macroscopic metastases to other organs are readily seen. Furthermore, differentiation between enlarged nodes and vessels is possible with MRI. Some authors recommended the use of MRI to stage renal cell carcinoma in patients with known contraindication to contrast, prior suboptimal bolus contrast enhanced CT scan, and equivocal CT findings. MRI can replace the inferior vena cavagram in the staging work-up and MR may be superior to CT for planning the surgical approach in Stage IIIA lesions by determining the upper extent of tumor thrombus within the inferior vena cava or the right atrium.(ABSTRACT TRUNCATED AT 400 WORDS)
单纯性肾囊肿在短TE和短TR的T1加权SE图像上呈低信号强度，这是因为囊液的T1值较长。随着TE和TR增加，由于囊液的T2值较长，囊肿信号强度增加。在T1加权图像上，复杂性囊肿的信号强度高于单纯性囊肿；可能无法将这些复杂性囊肿与实性肿块区分开来。MRI似乎有助于识别单纯性囊液，因此在对CT或超声认为复杂的囊性病变进行特征性描述方面具有潜力。不幸的是，成像技术尚未优化，诊断标准有些模糊，且在具有代表性的患者群体中准确性尚未确立。在MR图像上，实性肿块通常可以被识别并与单纯性、无并发症的囊肿区分开来。无法区分各种类型的实性肿瘤，或将其与复杂性囊肿或炎性肿块区分开来仍然是一个局限性。大多数病变在增强CT上比在MR图像上更容易显示，因此MRI在肾细胞癌检测和诊断中的作用仍然有限。尽管肾细胞癌的高检出率令人鼓舞，但在显示直径小于3cm的实性病变方面，CT仍比MR更敏感。MRI不能用作肾肿瘤的筛查方式。MRI在肾细胞癌分期方面似乎很有帮助。肉眼可见肿瘤向肾周脂肪的宏观扩展、肿瘤向肾静脉和下腔静脉的扩展以及向其他器官的宏观转移。此外，MRI能够区分增大的淋巴结和血管。一些作者建议，对于已知有对比剂禁忌证、之前团注对比剂增强CT扫描效果欠佳以及CT表现不明确的患者，使用MRI对肾细胞癌进行分期。在分期检查中，MRI可以替代下腔静脉造影，对于III A期病变，通过确定下腔静脉或右心房内肿瘤血栓的上界，在规划手术入路方面，MR可能优于CT。（摘要截选至400字）
