A Case Series of X-Linked Deafness-2 with Sensorineural Hearing Loss, Stapes Fixation, and Perilymphatic Gusher: MR Imaging and Clinical Features of Hypothalamic Malformations

A, Axial T2 image of a normal hypothalamus at the level of the optic radiations. B–G, Axial T2 images of the hypothalamus in a patient with DFNX2, which demonstrate progressive folding of the ventromedial hypothalamus. Note the presence of bilateral clefts in most cases, with external clefts being more easily recognizable (arrows). Internal clefts are also noted on B and C (arrowheads).

A, Coronal T2 anatomy of a normal hypothalamus showing the classic convex morphology of the medial eminence. B–H, High-resolution coronal T2 images show progressive bending of the ventromedial hypothalamus (from mild to severe). B, High-resolution coronal T2 image shows abnormal concavity at the junction between the ventromedial hypothalamus and the medial eminence, with a low-lying ventromedial hypothalamus (black arrow) in relation to the medial eminence (ME). These findings show an abnormal concave morphology of the hypothalamus in relation to the pituitary gland. C, Coronal T2 FLAIR image of another patient with DFNX2, which demonstrates isointense signal compared with the adjacent globus pallidus. Note again the characteristic bending of the ventromedial hypothalamus and its caudal location in relation to the medial eminence (white arrow). D, Measurement of the angle between the tip of the ventromedial hypothalamus and the septum pellucidum (white arrows). E, Measurement of the craniocaudal length of the ventromedial hypothalamus at the lowest point (black arrow) in relation to the basal forebrain (horizontal line). The basal forebrain (white arrowheads) is also indicated on images A and D. F and G, In some cases, the low-lying hypothalamus and the folding are so severe that some hypothalamic segments appear masslike, though the overall appearance is in keeping with diffuse folding. H, Severe hypothalamic bending in a patient with DFNX2, which shows cranial folding of the hypothalamus (black arrow) apart from the typical low-lying or hanging infundibular nucleus (not shown in this image).