Levy Lucien M, Degnan Andrew J, Sethi Ila, Henkin Robert I
From the *Department of Radiology, George Washington University Medical Center, Washington, DC; †University of Pittsburgh Medical Center, Pittsburgh, PA; and ‡The Taste and Smell Clinic, Washington, DC.
J Comput Assist Tomogr. 2013 Sep-Oct;37(5):650-7. doi: 10.1097/RCT.0b013e31829bfa3b.
There are 2 groups of patients with congenital smell loss: group 1 (12% of the total), in which patients exhibit a familial smell loss in conjunction with severe anatomical, somatic, neurological, and metabolic abnormalities such as hypogonadotropic hypogonadism; and a larger group, group 2 (88% of the total), in which patients possess a similar degree of smell loss but without somatic, neurological, or anatomical abnormalities or hypogonadism. Both groups are characterized by similar olfactory dysfunction, and both have been reported to have absent or decreased olfactory bulbs and grooves, which indicates some overlap in olfactory pathophysiology and anatomy. The purpose of this study was to evaluate patients with congenital smell loss, primarily among group 2 patients, comparing brain magnetic resonance imaging (MRI) results in patients with types of hyposmia.
Forty group 2 patients were studied by measurements of taste (gustometry) and smell (olfactometry) function and by use of MRI in which measurements of olfactory bulbs, olfactory sulcus depth, olfactory grooves, and hippocampal anatomy were performed. Anatomical results were compared with similar studies in group 1 patients and in 22 control subjects with normal sensory function.
Olfactometry was abnormal in all patients with no patient reporting ever having normal olfaction. No patient had a familial history of smell loss. On MRI, all exhibited at least 1 abnormality in olfactory system anatomy, including absence or decreased size of at least 1 olfactory bulb, decreased depth of an olfactory sulcus, and abnormalities involving hippocampal anatomy with hippocampal malrotations. One patient had bilateral bulb duplication. Normal subjects with normal smell and taste function exhibited some but very few or significant neuroanatomical changes on MRI.
Although both groups have similar abnormalities of smell function, group 2 patients demonstrate anatomical anomalies in olfactory structures that are neither as common nor as severe as in group 1 patients. Group 2 patients can have a wide range of olfactory anatomical abnormalities.
先天性嗅觉丧失患者分为两组：第1组（占总数的12%），患者表现为家族性嗅觉丧失，并伴有严重的解剖、躯体、神经和代谢异常，如促性腺激素缺乏性性腺功能减退；另一组人数较多，即第2组（占总数的88%），患者嗅觉丧失程度相似，但无躯体、神经或解剖异常或性腺功能减退。两组的特征均为相似的嗅觉功能障碍，且均有报道称嗅球和嗅沟缺失或变小，这表明嗅觉病理生理学和解剖学存在一些重叠。本研究的目的是评估先天性嗅觉丧失患者，主要是第2组患者，比较不同类型嗅觉减退患者的脑磁共振成像（MRI）结果。
对40例第2组患者进行味觉（味觉测量）和嗅觉（嗅觉测量）功能测量，并使用MRI对嗅球、嗅沟深度、嗅沟和海马解剖结构进行测量。将解剖学结果与第1组患者以及22名感觉功能正常的对照受试者的类似研究结果进行比较。
所有患者的嗅觉测量均异常，没有患者报告曾有正常嗅觉。没有患者有嗅觉丧失的家族史。在MRI上，所有患者的嗅觉系统解剖结构至少有1项异常，包括至少1个嗅球缺失或变小、嗅沟深度减小以及涉及海马解剖结构的异常，如海马旋转不良。1例患者双侧嗅球重复。嗅觉和味觉功能正常的受试者在MRI上表现出一些但非常少或不明显的神经解剖学变化。
虽然两组的嗅觉功能异常相似，但第2组患者嗅觉结构的解剖异常不如第1组患者常见和严重。第2组患者可出现广泛的嗅觉解剖异常。
