MRI findings of congenital dysosmia

Objective To study the MRI findings of congenital dysosmia. Methods Forty-seven patients with congenital dysosmia (39 with Kallmann syndrome and 8 with isolated dysosmia) and 21 normal volunteers underwent MRI examination. The features of congenital malformation were recorded. The volume of olfactory bulbs, depth of olfactory sulei as well as diameters of pituitary glands and stalks were measured. The rate of dysplasia of olfactory bulbs and tracts in the two patients groups was compared with χ2 test. The difference of volume of olfactory bulbs between the two groups was evaluated with nonparametrie test. And the difference of diameters of pituitary glands and stalks was analyzed with analysis of variance. Results All the patients had abnormal findings in olfactory bulbs, tracts and/or olfactory sulci on MR images. The patterns of congenital malformation may be dysplastic or hypoplastic, symmetric or asymmetric. The proportion of patients with dysplasia of olfactory bulbs and tracts in Kallmann syndrome patients ( 31/39 ) was higher than that in isolated dysosmia ones ( 2/8 ) ( χ2= 6. 998, P = 0. 008 ), and the olfactory bulbs' volume of patients with Kallmann syndrome ( median 8 mm3 ) was smaller than that of patients with isolated dysosmia ( median 22 mm3 ) ( Z = - 2. 902, P = 0. 004 ). The pituitary glands were smaller and the stalks were thinner in patients with Kallmann syndrome than those in volunteers [ the anteroposterior diameter of pituitary glands in Kallmann syndrome (7. 22±1.93) mm, that in normal volunteers (9. 94±1.59) ram, F=16.835, P=0. 000; height of pituitary glands in Kallmann syndrome (3.71±1.74) mm, that in normal volunteers (6. 00±1.24) ram, F = 16. 092, P = 0. 000; the anteroposterior diameter of pituitary stalks in Kallmann syndrome ( 1.19±0. 55 ) mm, that in normal volunteers ( 1.88±0. 49 ) mm, F = 13.060, P =0. 000]. Conclusions In congenital dysosmic patients, dysplasia or hypoplasia of olfactory bulbs, tracts and sulei can be clearly depicted on MR images. MR imaging is valuable for clinical diagnosis and treatment. Key words: Olfaction disorders;  Kallmann syndrome;  Magnetic resonance imaging