CT DIAGNOSIS OF RENAL ANGIOMYOLIPOMA - THE IMPORTANCE OF DETECTING SMALL AMOUNTS OF FAT
CT DIAGNOSIS OF RENAL ANGIOMYOLIPOMA - THE IMPORTANCE OF DETECTING SMALL AMOUNTS OF FAT
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DOI：
10.2214/ajr.151.3.497
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发表时间：
1988-09-01
影响因子：
5
通讯作者：
RAGHAVENDRA, BN
中科院分区：
文献类型：
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作者：
BOSNIAK, MA;MEGIBOW, AJ;RAGHAVENDRA, BN
对6名患有肾血管平滑肌脂肪瘤（1.2-4.0 cm）的患者进行了审查，其中CT上仅显示极少量脂肪。由于对肿瘤内的小区域低衰减进行了组织衰减测量，并且使用了薄层（5 mm）和非增强CT扫描，因此对病变的脂肪含量进行了评估。在3例病例中，病变的脂肪含量可在10 mm切片上识别，但在另外3例病例中仅在5 mm切片上识别。在两个病例中，仅在非增强的5 mm薄切片上可见脂肪。由于整个肿瘤上的单个感兴趣区域会在软组织范围内产生平均衰减，因此必须对肿块内的低密度区域进行仔细取样。使用5 mm薄切片和薄的非增强CT切片可提高空间和密度分辨率，降低对部分容积效应的敏感性。在一项相关研究中，在对100例边界清楚（4.0 cm或更小）的肾细胞癌进行审查时，未检测到脂肪区域。检测肾脏病变中脂肪的存在将确立血管平滑肌脂肪瘤的诊断，并且是唯一可以将其与肾细胞癌区分开的放射学发现。因此，在这些情况下将避免不必要的手术。
Six patients were reviewed who had renal angiomyolipoma (1.2-4.0 cm) in which only minimal amounts of fat were evident on CT. The fat content of the lesion was appreciated because tissue attenuation measurements of small areas of low attenutuation within the tumors were performed and because thin-section (5-mm) and nonenhanced CT scans were used. The fat content of the lesions could be identified on 10-mm sections in three cases but only on 5-mm sections in three others. In two cases, fat was seen only on the nonenhanced 5-mm thin sections. Careful sampling of low-density regions within the mass must be performed because a single region of interest over the entire tumor will produce an average attenutation in the soft-tissue range. The use of 5-mm thin sections and thin, nonenhanced CT sections increases spatial and density resolution and decreases susceptibility to partial-volume effects. In a correlative study, no areas of fat were detected in a review of 100 well-circumscribed (4.0 cm or smaller) renal cell carcinomas. Detecting the existence of fat in a renal lesion will establish the diagnosis of angiomyolipoma and is the only radiologic finding that can differentiate it from renal cell carcinoma. Thus, unnecessary surgery will be avoided in these cases.