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PURPOSE: To propose a new objective, video recording method for the classification of unilateral peripheral facial palsy (UPFP) that relies on mathematical algorithms allowing the software to recognize numerical points on the two sides of the face surface that would be indicative of facial nerve impairment without positioning of markers on the face. METHODS: Patients with UPFP of different House-Brackmann (HB) degrees ranging from II to V were evaluated after video recording during two selected facial movements (forehead frowning and smiling) using a software trained to recognize the face points as numbers. Numerical parameters in millimeters were obtained as indicative values of the shifting of the face points, of the shift differences of the two face sides and the shifting ratio between the healthy (denominator) and the affected side (numerator), i.e., the asymmetry index for the two movements. RESULTS: For each HB grade, specific asymmetry index ranges were identified with a positive correlation for shift differences and negative correlation for asymmetry indexes. CONCLUSIONS: The use of the present objective system enabled the identification of numerical ranges of asymmetry between the healthy and the affected side that were consistent with the outcome from the subjective methods currently in use.
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Parálisis de Bell , Parálisis Facial , Cara , Nervio Facial , Parálisis Facial/diagnóstico , Humanos , Grabación en VideoRESUMEN
PURPOSE: To report on failures related to active middle ear implants (AMEI) surgery, within a series of subjects treated at a single Implanting Center. METHODS: A retrospective review of 79 cases of implanted AMEI has been performed to report the failure ratio, the causes for the failure and the selected rehabilitative solution. The AMEI included 25 Vibrant Soundbridge® (Medel, Innsbruck, Austria), 20 as round window vibroplasty (RW-VSB) for mixed hearing loss, 5 as incus-vibroplasty for sensorineural hearing loss; 7 MET/Carina® (Cochlear, Melbourne, Australia), 2 MET for mixed and sensorineural hearing loss, 5 Carina for sensorineural hearing loss; 43 Esteem® (EnvoyMedical, St Paul, USA) for sensorineural hearing loss; 3 Maxum® (Ototronics, Texas, USA) for sensorineural hearing loss; 1 Codacs® (Cochlear, Melbourne, Australia) for severe mixed hearing loss. RESULTS: The overall complication rate affected 20% of the implanted devices, individually ranging from 6.9 to 100%. Hardware system failures were recorded in all the AMEI, ranging from 10 to 50%. The alternative auditory rehabilitation included replacement of the same system in 2 cases, use of a conventional hearing aid in 3 cases, Cochlear implantation in 4 cases and implantation in the contralateral ear in 2 cases. CONCLUSION: The present clinical experience showed that, in spite of the successful functional rate displayed by the majority of the AMEI implantees, complications may occur to a certain percentage of cases and should prompt the professionals to select alternative solutions, starting from the (re)adoption of a conventional hearing aid and ending up to Cochlear implantation.
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Audífonos , Perdida Auditiva Conductiva-Sensorineural Mixta , Pérdida Auditiva Sensorineural , Prótesis Osicular , Oído Medio/cirugía , Pérdida Auditiva Sensorineural/etiología , Pérdida Auditiva Sensorineural/cirugía , Humanos , Estudios Retrospectivos , Ventana Redonda/cirugía , Resultado del TratamientoRESUMEN
The aim of this study is to investigate whether, in addition to intratympanic steroid therapy, additional hyperbaric oxygen therapy (HBOT) sessions per day (twice a day for 5 days) is more useful than one session per day for 10 days in patients affected by severe and profound idiopathic sudden sensorineural hearing loss (ISSNHL). A total of 55 patients affected by unilateral severe and profound ISSNHL were recruited. Two protocols were adopted. In the first, 27 patients (13 with profound and 14 with severe hearing loss) underwent one session of HBOT per day for 10 days, 6 days a week. An HBOT session comprised a period of 14 minutes air compression followed by 90 min at 2.4 atm absolute (ATA) followed by a decompression period of 15 min in oxygen. Patients breathed 100% oxygen through an appropriate mask checked for leaks. Patients were given 0.4 ml of 62.5 mg/ml of intratympanic prednisolone during the first three days of the protocol. In the second protocol, 28 patients (10 with profound and 18 with severe hearing loss) received 10 sessions of HBOT, twice a day for five days, 2.4 ATA 90 min 100% oxygen. The intratympanic injections of prednisolone were given between the two sessions of HBOT during the first three days of the protocol. Since there were no significant differences in hearing outcomes between the two protocols, the present study shows that the protocol of two sessions of HBOT per day is a valid treatment and equally effective as the one HBOT session per day, but with shorter treatment time.
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Pérdida Auditiva Sensorineural/terapia , Pérdida Auditiva Súbita/terapia , Oxigenoterapia Hiperbárica , Audiometría de Tonos Puros , Humanos , Esteroides/uso terapéutico , Resultado del TratamientoRESUMEN
To analyze the presence of chronic cerebrospinal venous insufficiency parameter and vascular abnormalities, in the internal jugular veins (IJVs) and/or vertebral veins in sitting and supine posture, in patients with Meniere's disease compared to healthy general population. A prospective study on 32 patients affected by definite Ménière was performed from February 2012 to January 2013. All subjects underwent an echo-color Doppler examination of the cerebrospinal venous flow. 21 of the 32 Menieric patients showed a statistically significant reflux in the intracranial veins versus healthy (65.6 vs 25%; P < 0.001). A high prevalence of IJVs stenosis with hemodynamic changes (increased velocity or absence of flow) was observed (66.7 vs 33.3%; P < 0.05). The other parameters considered did not show statistically significant differences among the two groups. The results obtained showed a vascular pattern of cerebrospinal venous system present in patients affected by definite Meniere. This vascular impairment significantly affects the vascular areas more directly involved in the venous drainage of the inner ear. Thus venous stasis may be considered a further pathogenetic mechanism for development of Meniere's disease.
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Venas Yugulares/diagnóstico por imagen , Enfermedad de Meniere/complicaciones , Insuficiencia Venosa/etiología , Adulto , Enfermedad Crónica , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Ultrasonografía Doppler en Color , Insuficiencia Venosa/diagnóstico por imagenRESUMEN
This study was designed to investigate the indication and advantages of contralateral implantation after postimplant meningitis (piM). Speech perception assessment, most comfortable levels and high-resolution computer tomography were used to monitor cochlear fibrosis/ossification and clinical changes in outcomes in 5 children affected by meningitis after a variable-time post-cochlear implantation. Ipsilateral ossification was found in 3 children, 1 of whom developed delayed contralateral ossification. These children were implanted on the contralateral side as they all showed deterioration of hearing performance. Results from the present paper and literature analysis suggest that, (1) piM can induce ipsilateral and contralateral ossification, (2) meningitis-induced cochlear ossification is more prone to develop in the presence of a normal cochlear structure and (3) contralateral implantation after piM has proven to be effective in restoring performance when a full electrode insertion is accomplished.
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Implantación Coclear/efectos adversos , Implantes Cocleares , Sordera/cirugía , Meningitis Neumocócica/etiología , Percepción del Habla/fisiología , Adolescente , Niño , Preescolar , Cóclea/diagnóstico por imagen , Cóclea/cirugía , Enfermedades Cocleares/diagnóstico por imagen , Enfermedades Cocleares/cirugía , Implantación Coclear/métodos , Sordera/diagnóstico por imagen , Femenino , Pruebas Auditivas , Humanos , Masculino , Radiografía , Resultado del TratamientoRESUMEN
OBJECTIVE: This retrospective, comparative study aimed to assess anatomical and functional results in a group of adults undergoing type I tympanoplasty for subtotal tympanic membrane perforation, using two different types of graft. SUBJECTS AND METHODS: The study included 106 patients affected by chronic otitis media, who underwent underlay type I tympanoplasty, 53 using an autologous chondro-perichondral tragal graft and 53 using temporalis fascia. Anatomical and functional outcomes were evaluated over time. RESULTS: Audiometric results comparing the cartilage and fascia groups at six months and one year after surgery showed no statistically significant differences. Assessment of anatomical outcomes indicated a greater number of complications in the fascia group. CONCLUSION: Functional results indicate the validity of the cartilage tympanoplasty, while anatomical results indicate a slightly better outcome in terms of graft re-perforation and retraction, compared with temporalis fascia at one-year follow up. These results suggest that the cartilage technique is preferable for type I tympanoplasty.
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Pérdida Auditiva/cirugía , Perforación de la Membrana Timpánica/cirugía , Timpanoplastia/métodos , Adulto , Cartílago/trasplante , Fascia/trasplante , Femenino , Humanos , Masculino , Estudios Retrospectivos , Resultado del Tratamiento , Perforación de la Membrana Timpánica/fisiopatología , Timpanoplastia/efectos adversosRESUMEN
In the last few years, cartilage has been the preferred material for reconstruction of the tympanic membrane, particularly in the case of allergy, re-perforation, or total or subtotal perforation. The mechanical characteristics of cartilage offer the advantage of high resistance to retraction and re-perforation. This paper describes two original techniques which reduce cartilage tympanoplasty surgery time, involving a 0.3 mm thick cartilage-perichondrium composite graft to repair the tympanic membrane.
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Cartílago/cirugía , Miringoplastia/métodos , Perforación de la Membrana Timpánica/cirugía , Membrana Timpánica/cirugía , Timpanoplastia/métodos , Cartílago/trasplante , Humanos , Factores de TiempoRESUMEN
Thyroglossal duct cysts are most common neck masses after benign lymphonodes. They originate from primitive thiroglossal duct, so they could be locate along its course. Every mass in the middle line of the neck can be considered as a thyroglossal cyst. Best treatment is surgery (Sistrunk procedure). We present a case of unusual localization at floor of the mouth of thyroglossal in a 34 years old woman. To our knowledge in literature, only two cases, have been reported both.
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Suelo de la Boca , Quiste Tirogloso/patología , Quiste Tirogloso/cirugía , Adulto , Femenino , HumanosRESUMEN
Two unusual cases of cochlear implant (CI) surgery complication are reported: introduction of the electrode array into the superior semicircular canal with normal morphology and a growing amplitude of neural potential (neural response imaging, NRI) during intra-operative monitoring control. In the first case, a two-year-old patient affected by congenital sensorineural profound deafness was bilaterally implanted with two Clarion 90 k devices and intra-operative electrophysiological and radiological controls were performed. After introduction of the array in the right side NRI was performed and a neural potential was found only on two apical electrodes. Radiological intra-operative control with antero-posterior trans-orbital plain films was performed to assess the position of the electrodes inside the cochlea. Radiography showed the electrode array in the superior semicircular canal in the right ear. The electrode array was removed and reinserted correctly. In the second case, a 72-year-old man underwent left cochlear implantation for sensorineural profound deafness of unknown origin. Intra-operative electrophysiological testing (NRI) showed the presence of neural potential on three tested channels. In this case, as routinely employed since 2006, an intra-operative static fluoroscopy control was performed, this showed the electrode array in the superior semicircular canal. The electrode array was removed and reinserted correctly. In conclusion, intra-operative monitoring tests during CI surgery play different roles: measurement of impedances and NRI can evaluate the integrity of implant electrodes and the status of the electrode cochlea interface, but they cannot be the only way to confirm correct positioning of the array. In our opinion the intra-operative radiological check is helpful during CI surgery, especially when there is any doubt about correct electrode insertion.
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Implantación Coclear/efectos adversos , Implantación Coclear/métodos , Sordera/cirugía , Electrodiagnóstico , Complicaciones Intraoperatorias/diagnóstico , Monitoreo Intraoperatorio/métodos , Canales Semicirculares/diagnóstico por imagen , Anciano , Preescolar , Sordera/diagnóstico por imagen , Sordera/fisiopatología , Electrodos Implantados , Fluoroscopía , Humanos , Complicaciones Intraoperatorias/cirugía , MasculinoRESUMEN
A spontaneous CSF fistula of the sphenoid sinus was preoperatively diagnosed in a young woman presenting with massive pneumocephalus and rhinorrhea. Diagnosis was established by MR cisternography using a heavily T2-weighted 3D single-shot FSE sequence with half-Fourier analysis (3D-EXPRESS(®)), originally developed for imaging the inner ear. While unenhanced CT failed to detect the site of the fistula, MR permitted complete evaluation of the sellar/sphenoid region and tracked the CSF signal down to the nasal cavity.
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A rare case of cochlear implant surgery complication is described: air collection behind the ear. A 61-year-old male with a 20-year history of progressive bilateral profound sensorineural hearing loss underwent cochlear implant surgery on the left ear with Clarion Hi-Res 90K (Advanced Bionics, Sylmar, CA, USA). Ten days after surgery, the patient presented visible tumefaction behind the ear corresponding to the receiver-stimulator. Ultrasonography, with a probe of 30 MHz, of the surface behind the ear showed formation of probable liquid content but aspiration with a 20-gauge needle yielded 30 cm3 of air without blood or pus. An unusual case is described of a minor complication occurring in an adult cochlear implant patient presenting a swelling behind the ear that was found to be collected air. Although ultrasonography can be useful to evaluate localization of swelling behind the ear and to differentiate between liquid and solid collection, it is not useful for identification of air collection. The Eustachian tube test can show an abnormally patent tube and prevent this complication.
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Implantación Coclear/efectos adversos , Pérdida Auditiva Sensorineural/cirugía , Pérdida Auditiva Unilateral/cirugía , Aire , Implantes Cocleares , Pérdida Auditiva Sensorineural/diagnóstico por imagen , Pérdida Auditiva Unilateral/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias , UltrasonografíaRESUMEN
OBJECTIVES: The aim of this study was to document the occurrence of a cavernous haemangioma of the external auditory canal, and to review the literature on this pathology. METHODS: We report the clinical presentation, imaging studies, surgical procedure and histological findings for a cavernous haemangioma of the external auditory canal. RESULTS: This patient represents the fourth reported case of cavernous haemangioma affecting only the external auditory canal. A cavernous haemangioma of the external auditory canal, not affecting the tympanic membrane, was surgically removed, without post-operative complications. CONCLUSIONS: Cavernous haemangioma of the external auditory canal is a rare otological pathology. Computed tomography imaging is important in order to precisely define and localise the site and size of the lesion. Histological examination is necessary for the correct diagnosis of the pathology.
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Conducto Auditivo Externo/diagnóstico por imagen , Neoplasias del Oído/diagnóstico por imagen , Hemangioma Cavernoso/diagnóstico por imagen , Conducto Auditivo Externo/cirugía , Neoplasias del Oído/cirugía , Femenino , Hemangioma Cavernoso/cirugía , Humanos , Persona de Mediana Edad , Tomografía Computarizada por Rayos XRESUMEN
OBJECTIVE: We report a case of a rare cochlear implant complication: the introduction of the electrode array into the superior semicircular canal, with intra-operative measurements of neural response reactions suggesting reasonable functioning of the implant. CASE REPORT: A two-year old patient affected by congenital, profound, sensorineural deafness underwent bilateral cochlear implantation at the ENT clinic of the 'La Sapienza' University of Rome. Two Clarion 90k devices were implanted, and electrophysiological and radiological checks were performed. After the introduction of the array in the right side, neural response imaging was performed, and a neural potential was found only on two apical electrodes, at a stimulation intensity of 431 clinical units. The situation differed on the left side, where neural response imaging was present at a stimulation intensity of 300 clinical units on the two electrodes tested (one apical electrode (number three), and one middle electrode (number nine)). Intra-operative radiological assessment with a transorbital plain films was performed as usual in order to assess the position of the electrodes inside the cochlea. This radiography showed the electrode array to be in the superior semicircular canal in the right ear. CONCLUSION: Intra-operative monitoring tests during cochlear implant surgery play different roles; measurement of impedances and neural response imaging can evaluate the integrity of implant electrodes and the status of the electrode-cochlea interface, but it must not be the sole way in which correct positioning of the array is confirmed. In our opinion, intra-operative radiological assessment is mandatory during cochlear implant surgery.
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Implantación Coclear/métodos , Sordera/cirugía , Cuidados Intraoperatorios/métodos , Preescolar , Cóclea/diagnóstico por imagen , Sordera/congénito , Estimulación Eléctrica , Electrodos Implantados , Cuerpos Extraños/diagnóstico por imagen , Humanos , Radiografía , Canales Semicirculares/diagnóstico por imagenRESUMEN
CONCLUSION: The image quality of 64-MDCT provided excellent definition of the fine osseous structures and individual electrode contacts. Evaluation of electrode distances revealed a more focused stimulation for the Helix contacts, with better optimization of pulse width and frequency of stimulation. OBJECTIVES: A multi-slice CT scan was performed postoperatively to evaluate electrode distance from the modiolus and variability of fitting parameters (M level) for two different types of cochlear implant electrode carriers, CII and 90K implants with 1J and Helix electrode carriers. MATERIALS AND METHODS: The electrode's position in different cochlear implant (CI) electrodes, Advanced Bionics 90K 1J and Helix, was assessed postoperatively in 20 adult patients by means of a 64-MDCT scanner. Axial, coronal, and oblique 0.3 mm multiplanar reconstructions (MPRs) were obtained and datasets were analyzed to assess the intracochlear position and distance from the surface of the electrodes to the bony edge of the modiolus. Patients' fitting characteristics were gathered at the time the CT was performed and correlated to intracochlear measurements. RESULTS: Determination of contact distances confirmed smaller average values for the Helix at the apex and medial segments. Helix electrodes were closer to the modiolus in all segments. Likewise, M level determination showed lower values for the Helix carrier, confirming a more focused stimulation and better optimization of pulse width and frequency of stimulation.
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Umbral Auditivo/fisiología , Cóclea/diagnóstico por imagen , Implantación Coclear/métodos , Implantes Cocleares , Electrodos Implantados , Procesamiento de Imagen Asistido por Computador , Ajuste de Prótesis , Tomografía Computarizada Espiral , Adulto , Anciano , Cóclea/fisiopatología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Diseño de Prótesis , Ganglio Espiral de la Cóclea/diagnóstico por imagen , Ganglio Espiral de la Cóclea/fisiopatologíaRESUMEN
Two women with viral encephalitis of unknown etiology were studied with serial MR studies at 1.5 Tesla using: Spin-Echo (SE) T1-weighted (T1w) sequences before and after i.v. administration of paramagnetic contrast agent, with/without magnetization transfer (MT), Fast SE and Fluid-attenuated Inversion Recovery (FLAIR) T2-weighted sequences, Echo-Planar Single-Shot sequences for the assessment of water diffusivity (Diffusion Weighted, DW, and Apparent Diffusion Coefficient maps, ADC). The DW and T1w sequences with MT after contrast were most useful to detect the initial pathologic alterations, thereby reinforcing the clinical diagnostic hypothesis and prompting appropriate drug treatment, even if the laboratory data were not conclusive for viral etiology. In a later phase, both cases showed MR evidence of lacunar foci in the grey matter, and cortical laminar necrosis, probably indicating a concomitant hypoxic/ischemic mechanism.
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A fully automated magnetic resonance (MR) segmentation method for identification and volume measurement of demyelinated white matter has been developed. Spin-echo MR brain scans were performed in 38 patients with multiple sclerosis (MS) and in 46 healthy subjects. Segmentation of normal tissues and white matter lesions (WML) was obtained, based on their relaxation rates and proton density maps. For WML identification, additional criteria included three-dimensional (3D) lesion shape and surrounding tissue composition. Segmented images were generated, and normal brain tissues and WML volumes were obtained. Sensitivity, specificity, and reproducibility of the method were calculated, using the WML identified by two neuroradiologists as the gold standard. The average volume of "abnormal" white matter in normal subjects (false positive) was 0.11 ml (range 0-0.59 ml). In MS patients the average WML volume was 31.0 ml (range 1.1-132.5 ml), with a sensitivity of 87.3%. In the reproducibility study, the mean SD of WML volumes was 2.9 ml. The procedure appears suitable for monitoring disease changes over time. J. Magn. Reson. Imaging 2000;12:799-807.
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Encéfalo/patología , Procesamiento de Imagen Asistido por Computador , Imagenología Tridimensional , Imagen por Resonancia Magnética , Esclerosis Múltiple/diagnóstico , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valores de Referencia , Sensibilidad y EspecificidadRESUMEN
In 16 patients with probable Alzheimer's disease (AD; NINDS criteria, age range 56-78 years), gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) absolute and fractional volumes were measured with an unsupervised multiparametric post-processing segmentation method based on estimates of relaxation rates R1, R2 (R1 = 1/T1; R2 = 1/T2) and proton density [N(H)] from conventional spin-echo studies (Alfano et al. Magn. Reson. Med. 1997;37:84-93). Global brain atrophy, and GM and WM fractions significantly correlated with Mini-Mental Status Examination and Blessed Dementia Scale scores. Compared with normals, brain compartments in AD patients showed decreased GM (-6.84 +/- 1.58%) and WM fractions (-9.79 +/- 2.47%) and increased CSF fractions (+58.80 +/- 10.37%). Changes were more evident in early-onset AD patients. In AD, measurement of global brain atrophy obtained by a computerized procedure based on routine magnetic resonance studies could complement the information provided by neuropsychological tests for the assessment of disease severity.
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Enfermedad de Alzheimer/diagnóstico , Encéfalo/patología , Imagen Eco-Planar , Imagen por Resonancia Magnética , Anciano , Atrofia , Ventrículos Cerebrales/patología , Femenino , Humanos , Interpretación de Imagen Asistida por Computador , Masculino , Escala del Estado Mental , Persona de Mediana Edad , Pruebas NeuropsicológicasRESUMEN
UNLABELLED: An original method for simultaneous display of functional and anatomic images, based on frequency encoding (FE), merges color PET with T1-weighted MR brain images, and grayscale PET with multispectral color MR images. A comparison with two other methods reported in the literature for image fusion (averaging and intensity modulation techniques) was performed. METHODS: For FE, the Fourier transform of the merged image was obtained summing the low frequencies of the PET image and the high frequencies of the MR image. For image averaging, the merged image was obtained as a weighted average of the intensities of the two images to be merged. For intensity modulation, the red, green and blue components of the color image were multiplied on a pixel-by-pixel basis by the grayscale image. A comparison of the performances of the three techniques was made by three independent observers assessing the conspicuity of specific MRI and PET information in the merged images. For evaluation purposes, images from seven patients and a computer-simulated MRI/PET phantom were used. Data were compared with a chi-square test applied to ranks. RESULTS: For the depiction of MRI and PET information when merging color PET and T1-weighted MR images, FE was rated superior to intensity modulation and averaging techniques in a significant number of comparisons. For merging grayscale PET with multispectral color MR images, FE and intensity modulation were rated superior to image averaging in terms of both MRI and PET information. CONCLUSION: The data suggest that improved simultaneous evaluation of MRI and PET information can be achieved with a method based on FE.
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Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Tomografía Computarizada de Emisión , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Encefalopatías/diagnóstico , Encefalopatías/diagnóstico por imagen , Humanos , Fantasmas de ImagenRESUMEN
UNLABELLED: Thallium-201 is clinically used for the assessment of primary and recurrent brain tumors. The biologic properties of 201Tl that allow it to accumulate within the tumor cells render 201Tl useful in evaluating tumor malignancy, but its physical characteristics and nonroutine availability limits its use in some institutions, as compared to 99mTc-labeled compounds. The aim of this study was to assess the feasibility of using 99mTc-tetrofosmin for imaging brain tumors and to compare its uptake with that of 201Tl. METHODS: Twenty-six patients with 27 intracranial masses were studied with SPECT. In the first group of seven patients (Group A), the timing for optimal acquisition of the 99mTc-tetrofosmin scan was assessed. In the second group of 19 patients (Group B), two sequential 201Tl (74-148 MBq intravenous) and 99mTc-tetrofosmin (740-925 MBq intravenous) studies were performed 20 min after tracer injection and compared. RESULTS: In Group A, no significant difference in the tumor-to-background (T/B) ratio among the 20-, 40- and 120-min postinjection studies was observed. In Group B, the quality of reconstructed images with 99mTc-tetrofosmin, judged visually, was superior to that of 201Tl in 47% of all studies and was comparable in the remaining 53%. A significant relationship between 201Tl and 99mTc-tetrofosmin T/B ratio (r = 0.75, p < 0.01) was found. The T/B ratio of 99mTc-tetrofosmin was significantly higher than that of 201Tl (23.3 +/- 21.5 compared to 6.1 +/- 2.9, p < 0.005). CONCLUSION: Technetium-99m-tetrofosmin is a suitable radiotracer for the imaging of intracranial lesions with SPECT. Moreover, a better definition of tumor margins and a higher contrast between neoplastic and normal brain tissue can be achieved.
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Neoplasias Encefálicas/diagnóstico por imagen , Compuestos Organofosforados , Compuestos de Organotecnecio , Radiofármacos , Radioisótopos de Talio , Tomografía Computarizada de Emisión de Fotón Único , Neoplasias Encefálicas/diagnóstico , Estudios de Factibilidad , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Talio , Tomografía Computarizada por Rayos XRESUMEN
To assess the inter-study variability of a recently published unsupervised segmentation method (Magn. Reson. Med. 1997;37:84-93), 14 brain MR studies were performed in five normal subjects. Standard deviations for absolute and fractional volumes of intracranial compartments, which reflect the experimental variability, were smaller than 16.5 ml and 1.1%, respectively. By comparing the experimental component of the variability with the variability observed in our reference database, an estimate of the biological variability of the intracranial fractional volumes in the database population was obtained.