A Case of Bilateral Horizontal Semicircular Canal Dysplasia with Normal Cochlea: Three Dimensional Volume Rendering Image Using MR CISS Sequence / 대한평형의학회지

Congenital inner ear malformations are frequently found in patients with sensorineural hearing loss, but isolated vestibular anomalies with normal cochlear development have been rarely reported. We report a 20-year-old man with recurrent dizziness and disequlibrium without hearing impairment. Neuro-otological evaluations showed a left peripheral vestibulopathy with normal hearing function. Three dimensional volume rendering image using magnetic resonance constructive interference in steady state sequence demonstrated isolated vestibular anomalies involving bilateral horizontal semicircular canals. Isolated vestibular anomalies might not be as rare as previously thought among patients with recurrent dizziness, and should be carefully evaluated through various imaging techniques.

Congenital Inner Ear Malformation: Three Dimensional Volume Rendering Image Using MR CISS Sequence

PURPOSE: To evaluate three-dimensional volume-rendering of congenital inner-ear malfornations using the MR CISS (Constructive Interference in Steady State) sequence. MATERIALS AND METHODS: MR CISS images of 30 inner ears of 15 patients (M:F=10:5; mean age, 6.5years) in whom inner-ear malfornation was suspected were obtained using a superconducting Magnetom Vision System (Simens, Erlangen, Germany), with TR/TE/FA parameters of 12.25 ms/5.9 ms/70 degree. The images obtained were processed by means of the volume rendering technique at an advanced workstation (Voxtol 3.0.0; GE Systems, advanced workstation, volume analysis). The cochlea and three semicircular canals were morphologically evaluated. RESULTS: Volume-rendered images of 25 inner ears of 13 patients demonstrated cochlear anomalies in the form of incomplete partition (n=18), hypoplasia (n=2), and severe hypoplasia (n=5). For the superior semicircular canal, findings were normal in 15 ears, though common crus aplasia (n=6), hypoplasia (n=4), aplasia (n=3), and a short and broad shape (n=2) were also observed. The posterior semicircular canal of 13 ears was normal, but common crus aplasia (n=6), a short and broad shape (n=5), aplasia (n=4), hypoplasia (n=3) were also identified. Twelve lateral semicircular canals, were normal, but other images depicted a short and broad shape (n=7), a dilated crus (n=5), a broad shape (n=4), and aplasia (n=2). In 14 patients the anomalies were bilateral, and in seven, the same anomalies affected both ears. CONCLUSION: Three-dimensional volume rendering images of the inner ear depicted various morphological abnormalities of the cochlea and semicircular canals. At that locations, anomalies were more complicated and varied than in the cochlea. Three-dimensional volume rendering imaging using the MR CISS technique provides anatomical information regarding the membranous labyrinth, and we consider this useful in the evaluation of congenital inner ear malformations.