technetium-tc-99m-exametazime and Hearing-Loss--Sensorineural

Perfusion of the areas of cochleovestibular structures was investigated using Tc-99m HMPAO single photon emission computerized tomography (SPECT) in the young patients with vertigo presumed to have peripheral vestibular abnormalities and compared the results with cochleovestibular test results, and vertebrobasilar angiography findings.. The study was performed on 20 patients with vertigo and 17 control subjects who had performed vertebral arteriography due to another disease. The patients with vertigo presumed to be on peripheral vestibular disorder were included in the study. Systemic and otorhinolaryngological examination were carried out. Audiovestibular function was evaluated in all patients and control subjects. Brain SPECT was performed with a one-head rotating gamma camera system from 64 projections into a 64x64 matrix, using low energy and high-resolution fan beam collimators with a sampling time of 30 s. The images taken from cerebellum, temporal, parietal and occipital lobes which are supplied by a vertebrobasilar system were compared visually with the other side and asymmetry in the perfusion was searched. After cochleovestibular tests and laboratory had been completed, vertebral arteriography was performed bilaterally in all patients. Results of digital subtraction angiography (DSA) and the vestibulocochlear test were compared with images of SPECT. Data analysis was done with Yates Chi(2) and percentages of sensitivity and specificity were calculated.. There was vestibular test and cochlear test abnormalities in eight and ten of the patients with vertigo, respectively. SPECT imaging showed hypoperfusion and decreased regional blood flow in 12 of the patients. There was statistically significant differences between the study and control groups in SPECT (P<0.05). Five patients showed abnormal findings in DSA examinations.. It is believed that SPECT may be helpful in the detection of vascular pathology in the patients with vertigo.

Topics: Adult; Angiography, Digital Subtraction; Audiometry, Pure-Tone; Brain; Cerebrovascular Circulation; Cochlea; Female; Hearing Loss, Sensorineural; Humans; Male; Radiopharmaceuticals; Sensitivity and Specificity; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Vertebrobasilar Insufficiency; Vertigo; Vestibular Function Tests; Vestibule, Labyrinth

To explore functional neuroanatomical responses to auditory stimulation before and after implantation.. A prospective study of three cochlear implant candidates (pure-tone averages of 90 dB HL or greater bilaterally and hearing in noise test [HINT] performances of <40%) in which regional cerebral blood flow (rCBF) was assessed using single photon emission computed tomography (SPECT).. Candidates watched a 15-minute videotaped story under four conditions: audio presented monaurally in the right and left ears (aided), audio presented binaurally (aided), and visual-only presentation of the story. Five minutes into each story, 20 to 25 mCi of technetium 99m (99mTc) hexamethyl-propyleneamine-oxime (HMPAO) (Ceratec; Nycomed Amersham, Princeton, NJ, U.SA) was injected over a 30-second period to ensure that subjects were unaware of tracer administration. Subjects were scanned for 20 minutes using a PRISM 3000 gamma camera (Picker International, Cleveland, OH, U.S.A.). Data were normalized and co-registered, and subtraction images were compiled. Subtraction images contrasted activation patterns generated under the visual-only control condition to the auditory activation states acquired monaurally and binaurally.. Right and left ear monaural stimulation in normal hearing subjects resulted in significant bilateral activation of Brodmann areas 41, 42, 21, 22, and 38. Although substantial intersubject response variability was noted, subjects generally failed to bilaterally activate these areas under monaural hearing aid presentations; however, bilateral activation of areas 41 and 22 was noted under binaural presentations.. Despite relatively similar hearing losses in each ear, significant differences in preoperative auditory cortex activation were observed between ears. These data suggest that functional brain imaging provides a useful tool for exploring the responsiveness of the auditory cortex in cochlear implant candidates.

Topics: Acoustic Stimulation; Adult; Aged; Audiometry, Pure-Tone; Auditory Cortex; Auditory Threshold; Cerebrovascular Circulation; Cochlear Implants; Female; Frontal Lobe; Gamma Cameras; Hearing; Hearing Aids; Hearing Loss, Bilateral; Hearing Loss, Sensorineural; Humans; Image Processing, Computer-Assisted; Male; Middle Aged; Noise; Preoperative Care; Prospective Studies; Radiopharmaceuticals; Speech Perception; Subtraction Technique; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon