Marx H F, Colletti P M, Raval J K, Boswell W D, Zee C S
Los Angeles County-USC Medical Center, Department of Radiology 90033.
Magn Reson Imaging. 1990;8(3):223-9. doi: 10.1016/0730-725x(90)90093-h.
T1 and T2 relaxation time shortening secondary to paramagnetic compounds has been described in melanoma. The purpose of this paper is to evaluate the signal behavior of melanoma involved in various body areas using short TR, TE and long TR, TE sequences. Twenty-seven sites of melanoma were evaluated with MR using T1 weighted and T2-weighted techniques. Using fat and muscle signal intensities as references tissues, lesions were graded into high, low or intermediate intensity categories for each of the sequences. Four signal patterns emerged. The typical pattern characterized by high signal on T1-weighted images and low signal on T2-weighted images reflected T1 and T2 shortening. The other pattern categories comprised of lesions demonstrating low signal T1-weighted images and high signal on T2-weighted images, high signal on both T1- and T2-weighted images and lesions showing intermediate signal on either T1- or T2-weighted images. We observed a tendency away from the typical signal pattern in extraocular melanoma cases with only one of 14 demonstrating this pattern. Moreover, only seven of thirteen ocular melanomas exhibited such behavior. Possible explanations for this findings as well as the existence of a variety of MR appearances to melanoma are offered. We conclude that while signal patterns showing T1 and T2 shortening are typical of melanoma, the absence of these does not exclude the diagnosis.
黑色素瘤中已描述了继发于顺磁性化合物的T1和T2弛豫时间缩短。本文的目的是使用短TR、TE序列以及长TR、TE序列评估累及身体不同部位的黑色素瘤的信号表现。对27个黑色素瘤部位进行了磁共振成像（MR）检查，采用T1加权和T2加权技术。以脂肪和肌肉信号强度作为参照组织，将每个序列的病变分为高、低或中等强度类别。出现了四种信号模式。典型模式的特征是T1加权图像上呈高信号，T2加权图像上呈低信号，反映了T1和T2缩短。其他模式类别包括在T1加权图像上呈低信号而在T2加权图像上呈高信号的病变、在T1加权和T2加权图像上均呈高信号的病变以及在T1或T2加权图像上呈中等信号的病变。我们观察到眼外黑色素瘤病例有偏离典型信号模式的趋势，14例中只有1例表现出这种模式。此外，13例眼内黑色素瘤中只有7例表现出这种行为。本文对这一发现以及黑色素瘤存在多种MR表现的情况给出了可能的解释。我们得出结论，虽然显示T1和T2缩短的信号模式是黑色素瘤的典型表现，但没有这些表现并不能排除诊断。
