INTRACRANIAL METASTATIC MELANOMA - CORRELATION BETWEEN MR-IMAGING CHARACTERISTICS AND MELANIN CONTENT
INTRACRANIAL METASTATIC MELANOMA - CORRELATION BETWEEN MR-IMAGING CHARACTERISTICS AND MELANIN CONTENT
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DOI：
10.2214/ajr.165.6.7484597
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发表时间：
1995-12-01
影响因子：
5
通讯作者：
KUMAR, AJ
中科院分区：
文献类型：
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作者：
ISIKLAR, I;LEEDS, NE;KUMAR, AJ
objective.初步报告的基础上有限的情况下提出，特定的MR成像模式可能允许黑色素瘤患者的黑色素和无色素脑转移瘤之间的区别，本研究的目的是测试这一假设进行分类的MR图像从一个大系列的患者和相关的结果与手术切除的转移瘤中的黑色素细胞的百分比。回顾性分析30例经手术病理证实的脑内黑色素瘤的MRI表现。MRI平扫时，横断面和矢状面采用自旋回波T1加权序列，横断面采用质子密度加权和T2加权序列。静脉注射钆喷酸葡胺（0.1 mmol/kg体重）后，在轴向和冠状面获得T1加权图像。所有患者均行肿瘤全切除术，回顾其MRI表现，并根据可能的类型分为4组：（1）黑色素型：T1加权像相对于皮质呈高信号，T2加权像相对于皮质呈低信号，质子密度加权像相对于皮质呈等或高信号;（2）T1加权像呈低信号或等信号，T2加权像和质子密度加权像呈高信号或等信号，（3）不符合前两种类型之一的不确定或混合型MR影像特征;（4）血肿模式-仅表现血肿特征的MR影像学特征。由神经病理学家（G.N.F.）独立审查所有评价病变的组织切片，计算每个切除的转移灶中含黑色素肿瘤细胞的百分比，然后将MRI数据与组织学数据进行比较，以评估MRI模式的预测价值。42个转移性病灶被确定并按MR成像模式分类如下：10个黑色素性，11个不确定（混合），16个无黑色素性，5个血肿。与组织学结果的相关性显示，大多数（7/10）表现出黑色素MR成像模式的病变含有超过10%的含黑色素细胞，超过一半（9/16）表现出无黑色素MR成像模式的病变含有组织学可识别的黑色素（但总是在少于10%的细胞中），并且表现出混合MR成像模式的病变是无黑色素的或含有少于10%的黑色素细胞。相反，大多数病变（7/8）含有10%以上的黑色素细胞，表现出典型的黑色素病变的MRI图像，含有10%以下黑色素细胞的病变表现出多种MRI图像，只有约一半的无色素病变（6/13）表现出特征性的无色素病变的MRI图像。对于5个病灶，黑色素含量的潜在信息成像数据被组织学记录的血肿形成所掩盖。只有少数黑色素瘤转移瘤具有黑色素瘤的预期MR成像表现，包括T1加权图像上相对于皮质的高信号强度和T2加权图像上相对于皮质的低信号强度。在确实表现出这种黑色素模式的肿瘤中，大多数都有超过10%的含黑色素细胞。无色素黑色素瘤的推定MR成像模式是非特异性的，因为超过一半的具有这种模式的肿瘤含有黑色素。
OBJECTIVE. Preliminary reports based on limited numbers of cases have proposed that specific MR imaging patterns may permit a distinction between melanotic and amelanotic brain metastases in melanoma patients, The purpose of this study was to test this hypothesis by categorizing MR images obtained from a large series of patients and correlating the results with the percentage of melanin-containing cells in surgically resected metastases.SUBJECTS AND METHODS. The MR images of 30 patients with histologically proven intracerebral melanoma were reviewed retrospectively. Precontrast MR images were obtained with T1-weighted spin-echo sequences in axial and sagittal sections and with proton density-weighted and T2-weighted sequences in axial sections. After IV injection of gadopentetate dimeglumine (0.1 mmol/kg of body weight), T1-weighted images were obtained in axial and coronal sections. All patients had undergone gross total resection of the evaluated lesions, MR images of the metastases were reviewed and sorted into four groups on the basis of putative patterns: (1) melanotic pattern-hyperintense in relation to cortex on T1-weighted images, hypointense in relation to cortex on T2-weighted images, and isointense or hyperintense in relation to cortex on proton density-weighted images; (2) amelanotic pattern-hypointense or isointense in relation to cortex on T1-weighted images and hyperintense or isointense in relation to cortex on T2-weighted and proton density-weighted images; (3) indeterminate, or mixed, pattern-MR imaging characteristics that did not conform to those of one of the first two categories; and (4) hematoma pattern-MR imaging features that exhibited only hematoma characteristics. Tissue sections from all evaluated lesions were independently reviewed by a neuropathologist (G.N.F.), and the percentage of melanin-containing tumor cells in each resected metastatic lesion was estimated, The MR imaging data and histologic data were then compared to assess the predictive value of the MR imaging patterns.RESULTS. Forty-two metastatic lesions were identified and categorized by MR imaging pattern as follows: 10 melanotic, 11 indeterminate (mixed), 16 amelanotic, and five hematoma. Correlation with histologic findings revealed that a majority (7/10) of lesions that exhibited a melanotic MR imaging pattern had more than 10% melanin-containing cells, over half (9/16) of lesions that exhibited an amelanotic MR imaging pattern contained histologically identifiable melanin (but always in less than 10% of cells), and lesions that exhibited a mixed MR imaging pattern were either amelanotic or contained less than 10% melanotic cells, Conversely, a majority of lesions containing more than 10% melanotic cells (7/8) demonstrated the typical melanotic MR imaging pattern, lesions with less than 10% melanin-containing cells exhibited a variety of MR imaging patterns, and only about half of patients with amelanotic lesions (6/13) showed the characteristic amelanotic MR imaging pattern. For five lesions, potentially informative imaging data on melanin content was obscured by histologically documented hematoma formation.CONCLUSION. Only a minority of melanoma metastases have the anticipated MR imaging findings of melanotic melanoma, which consist of high signal intensity relative to that of cortex on T1-weighted images and low signal intensity relative to that of cortex on T2-weighted images. Of tumors that do exhibit this melanotic pattern, the majority have more than 10% melanin-containing cells, The putative MR imaging pattern for amelanotic melanoma is nonspecific, as over half of tumors with this pattern contain melanin.