Fuerxer F, Carlier R, Iffenecker C, Schaison G, Doyon D
Service de Radiologie, Hôpital Raymond Poincaré, Garches.
J Neuroradiol. 1996 Dec;23(4):223-30.
Kallmann syndrome is a disease clinically characterized by the association of hypogonadotrophic hypogonadism and anosmia or hyposmia. Most cases have been recorded among men. It is a genetic disorder with a specific gene location on the X chromosome. The cells that normally express luteinizing hormone-releasing hormone or LHRH fail to migrate the olfactory placode to the forebrain. The lateral projections of the olfactory placode also fail to induce development of the olfactory bulbs and tracts.
The aim of this study was to compare the MRI appearance of the olfactory sulci, the olfactory bulbs and frontal lobe between groups. The first reference group was composed of 20 subjects and the second group of 18 patients suffering from Kallmann syndrome. For all studies we used a 1.5 T magnet system (Signa GE). We performed two sagittal and coronal T1-weighted sequences in spin echo (TR = 600 ms, TE = 12 ms) with interleaved 3 mm slices and a 14 cm field of view.
In the first group, the two olfactory bulbs were always seen on coronal slices just behind the crista galli measuring 2 to 3.2 mm transversally. On sagittal slices, in 60% of the cases two bulbs were seen (3 mm laterally of the pituitary stalk) and in the other 40% only one bulb was seen. The length of the bulb has been measured between 6 and 11 mm. We noticed a plat frontal lobe in 85% of the cases. In the second group the olfactory bulbs were never visible among the 18 patients suffering from Kallmann syndrome. The hypoplasic sulci were hardly visible and their size was less or equal to 1 cm and the frontal lobe was triangular in 80% of the cases. One patient had hypoplasia of corpus callosum.
MRI is helpful tool to demonstrate abnormalities of the olfactory system which are always present among patients suffering from Kallmann syndrome. MRI can also show, at the same time, a possible associated brain abnormality.
卡尔曼综合征是一种临床特征为低促性腺激素性性腺功能减退与嗅觉缺失或嗅觉减退相关联的疾病。大多数病例记录于男性。它是一种遗传性疾病，在X染色体上有特定的基因定位。正常表达促黄体生成素释放激素（LHRH）的细胞无法从嗅基板迁移至前脑。嗅基板的外侧突起也无法诱导嗅球和嗅束的发育。
本研究的目的是比较两组之间嗅沟、嗅球和额叶的MRI表现。第一对照组由20名受试者组成，第二组为18名患有卡尔曼综合征的患者。所有研究均使用1.5T磁体系统（通用电气Signa）。我们在自旋回波中进行了两个矢状位和冠状位T1加权序列（TR = 600 ms，TE = 12 ms），层厚3mm，层间距交错，视野为14cm。
在第一组中，在冠状位切片上总能在鸡冠后方看到两个嗅球，横向测量为2至3.2mm。在矢状位切片上，60%的病例可见两个嗅球（位于垂体柄外侧3mm处），另外40%的病例仅见一个嗅球。嗅球长度测量为6至11mm。我们注意到85%的病例存在额叶扁平。在第二组中，18名患有卡尔曼综合征的患者中从未见到嗅球。发育不全的嗅沟几乎不可见，其大小小于或等于1cm，80%的病例中额叶呈三角形。一名患者胼胝体发育不全。
MRI是一种有助于显示卡尔曼综合征患者中总是存在的嗅觉系统异常的工具。MRI同时还能显示可能存在的相关脑部异常。
