Beck Christopher, Riel-Romero Rosario, Gonzalez-Toledo Eduardo
Louisiana State University School of Medicine, Shreveport, LA, USA.
J La State Med Soc. 2009 Jul-Aug;161(4):207-8, 210.
We present a case of a young girl complaining of headaches in whom a hypointense area was found in the pituitary gland with a standard magnetic resonance (MR) image of the head. This finding did not agree with clinical symptoms, so a dedicated MR of the sellar region was obtained. We determined that the supposed mass was artifact caused by volume averaging. Volume averaging is the effect of expressing the average density of two structures of a 3D slice on a 2D image. Increased slice thickness leads to increased volume averaging and decreased resolution. Dedicated MR uses thinner 3D slices to reconstruct an image and thus has better spatial resolution than standard MR. We emphasize the need of dedicated MR to evaluate pituitary lesions.
我们报告一例主诉头痛的年轻女孩，其头部标准磁共振（MR）图像显示垂体有一个低信号区。这一发现与临床症状不符，因此对鞍区进行了专门的MR检查。我们确定所谓的肿块是由容积平均效应导致的伪影。容积平均效应是指在二维图像上显示三维切片中两个结构的平均密度的效应。切片厚度增加会导致容积平均效应增加，分辨率降低。专门的MR使用更薄的三维切片来重建图像，因此比标准MR具有更好的空间分辨率。我们强调评估垂体病变需要专门的MR检查。
