Uduma Felix Uduma, Titalom Kamga
Abia State University Teaching Hospital, Aba, Nigeria.
Glob J Health Sci. 2011 Dec 29;4(1):253-8. doi: 10.5539/gjhs.v4n1p253.
Magnetic resonance imaging is a non-invasive modern imaging tool that can definitely diagnose malignant melanoma despite its anatomic localisations. This is borne out of tumour paramagnetic melanin pigment content. Melanin is known to shorten T1 and T2 relaxation times of protons thereby exhibiting hyperintense T1W and hypointense T2W signals, hence conferring some histiological diagnosis. This is unlike Amelanotic melanoma, other intra-orbital tumours and tumours in general that show usual hypointense T1W and hyperintense T2W signals. However a few mimics of signal characteristics of malignant melanoma like sub-retinal serous collection exist. This therefore needs additional MRI sequences like fat suppression with Gado-pentetate Dimeglumine enhancement for differentiations.
磁共振成像（MRI）是一种非侵入性的现代成像工具，无论恶性黑色素瘤位于身体的哪个解剖部位，它都能明确诊断。这是由肿瘤中顺磁性黑色素的含量决定的。众所周知，黑色素会缩短质子的T1和T2弛豫时间，从而在T1加权像（T1WI）上呈现高信号，在T2加权像（T2WI）上呈现低信号，这有助于进行一些组织学诊断。这与无色素性黑色素瘤、其他眶内肿瘤以及一般肿瘤不同，后者通常在T1WI上呈现低信号，在T2WI上呈现高信号。然而，存在一些类似于恶性黑色素瘤信号特征的情况，如视网膜下浆液性积液。因此，这需要额外的MRI序列，如使用钆喷酸葡胺增强的脂肪抑制序列来进行鉴别。
