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Ectopic thyroid gland tissue can occur either as the only detectable thyroid gland tissue or in addition to a normotopic thyroid gland. After a total thyroidectomy thyroid-stimulating hormone (TSH) can induce a compensatory volume increase of previously asymptomatic ectopic tissue. This hyperplastic ectopic tissue can occur as an unclear cervical space-occupying lesion. Prior to surgical exploration of an unclear cervical mass the possibility of ectopic thyroid tissue should be included in the differential diagnostic considerations.

Background: The insertion of the stapes piston into the vestibule provides the physical basis for a successful stapedotomy. In routine clinical practice, two different ways to handle prosthesis length are performed: (1) an individualized measurement of the stapes prosthesis length or (2) a standard prosthesis length for all cases. Objective: The objective of this study was to compare both ways of handling prosthesis length and the effect of these methods on insertional prosthesis depth. Material and Method: We retrospectively evaluated 39 patients after performing a stapedotomy for radiologically estimated vestibular stapes prosthesis insertion depth. The individual measured length data were hypothetically changed to a standard length of 4.75, 5, 5.25, and 5.5 mm, and the insertion depths were compared. Results: The individually measured prosthesis lengths led to an insertion depth between 0.2 and 1.6 mm (mean 0.74 mm). The ratio of insertion depth/vestibular depth was between 8 and 59.1% (mean 26.6%). The different assumed standard lengths led to different rates of the vestibulum positions and possible bony contacts at the vestibulum floor. Conclusion: The individual measurement led to a zero rate of the vestibulum positions of stapes prosthesis pistons with a low insertion depth/vestibular depth ratio.

Ectopic thyroid gland tissue can occur either as the only detectable thyroid gland tissue or in addition to a normotopic thyroid gland. After a total thyroidectomy thyroid-stimulating hormone (TSH) can induce a compensatory volume increase of previously asymptomatic ectopic tissue. This hyperplastic ectopic tissue can occur as an unclear cervical space-occupying lesion. Prior to surgical exploration of an unclear cervical mass the possibility of ectopic thyroid tissue should be included in the differential diagnostic considerations.

Background: The insertion of the stapes piston within the vestibule provides the physical basis for a successful stapedotomy. An insertion depth of 0.5 mm is recommended to avoid the dislocation of...

Valutazione con RMN 3-T della posizione degli elettrodi degli impianti cocleari nella scala cocleare.La valutazione del posizionamento dell’elettrodo di un impianto cocleare avviene generalmente mediante tecniche che utilizzano radiazioni ionizzanti come la tomografia computerizzata multi-slice (MSCT), la tomografia a volume digitale (DVT) o la tomografia flat-panel (FPT). Recenti sviluppi nella gestione degli artefatti in risonanza magnetica (MRI) e la possibilità di eseguire MRI senza arrecare comorbidità al paziente impiantato, hanno dimostrato che l’applicazione della MRI a 1,5 T è possibile per stimare il posizionamento dell’elettrodo di un impianto cocleare. Lo scopo dello studio è indagare il posizionamento scalare di un elettrodo a parete per mezzo di MRI a 3 T. In questo studio prospettico sono stati arruolati 10 pazienti sottoposti ad impianto cocleare dotato di magnete bipolare, con elettrodo posizionato a livello intrascalare a parete. I pazienti sono stati valutati con MRI a 3 T, in sequenze T2-pesate con risoluzione di 0,8 mm, assiali e coronali. La posizione intracocleare dell’elettrodo osservata nelle sequenze MRI è stata comparata con quella ottenuta in DVT, eseguita routinariamente nel periodo postoperatorio. In tutti i casi la posizione scalare dell’elettrodo stimata in MRI era sovrapponibile a quella evidenziata in DVT. In tutti i casi è l’elettrodo è stato osservato nella scala timpanica. La posizione dell’elettrodo è stata valutata in modo affidabile a livello del giro basale della coclea, al contrario, la visualizzazione dell’elettrodo nei giri cocleari successivi è risultata difficoltosa. La valutazione con tecniche di MRI a 3 T del posizionamento dell’elettrodo a parete è possibile per il giro basale della coclea. La tipologia di elettrodo gioca un ruolo fondamentale nella stima visiva.Common techniques to evaluate intracochlear electrode position include ionised radiation by multi-slice computer tomography, digital volume tomography (MSCT, DVT) and flat panel tomography (FPT). Recent advances in the knowledge about handling MRI artefacts and the pain-free performance of MRI scans in cochlear implantees showed that estimation of the intracochlear electrode position is possible at 1.5 T with perimodiolar or midmodiolar arrays. The aim of the present study is to evaluate the assessment of the ipsilateral scalar position of a cochlear implant lateral wall electrode by MRI sequences at 3T. In a prospective study we evaluated 10 patients implanted with a diametrically bipolar implant magnet system with a lateral wall electrode in the intrascalar electrode position in an axial and coronal position and a T2 weighted sequence at 3T and a resolution of 0.8 mm. We compared the intracochlear position with routine postoperative DVT scan. In all cases, the MRT-estimated scalar position corresponded with that estimated by DVT scan. In all cases, a scala tympani position was present. While the position in the basal turn is reliably localisable, the first-turn visual assessment is difficult. Estimation of the intracochlear position of lateral wall cochlear implant electrodes by 3T MRI is possible for the basal turn. Electrode design plays a major role in visual assessment.

The cobaltous acetate-catalyzed autoxidation of benzaldehyde in acetic acid has been investigated and the nature and the mechanism of the oxidation at high cobaltous concentration (1·2–5 × 10–3 M) has been studied in detail. The induction period appearing at the beginning of the limiting rate region is explained by the inhibition brought about by the cobaltous ions. The inhibiting effect of the transition metal ions studied has been shown to be due to their electronic structure. The limiting rate of oxidation at high cobalt concentrations could be explained on the basis of the steady-state concentration of perbenzoic acid produced by the catalyst.