RESUMEN
Foram conduzidos dois experimentos em laboratório e em condições de campo para avaliação da eficiência térmica da embalagem Tetra Pak(r)como isolante térmico em escamoteadores aquecidos. No experimento em laboratório, foi utilizado o delineamento inteiramente ao acaso, adotando-se dois tratamentos (com e sem revestimento de embalagens Tetra Pak(r)) com 15 repetições (dias). O experimento em condições de campo foi conduzido na sala de maternidade de suínos. O delineamento foi inteiramente ao acaso, adotando-se dois tratamentos com 12 repetições. Os tratamentos foram: escamoteadores aquecidos com e sem revestimento interno com embalagem Tetra Pak(r). Foram medidos os dados de temperatura ambiente, umidade relativa do ar, temperatura superficial do piso, temperatura superficial da pele, comportamento e ganho de peso dos leitões lactentes. O uso da embalagem Tetra Pak(r)como isolante térmico no revestimento de escamoteadores manteve a temperatura ambiente confortável (32°C), proporcionando conforto térmico aos leitões lactentes.
Two experiments were conducted in laboratory and field conditions to evaluate the thermal efficiency of the Tetra Pak packaging as insulation in heated creeps. In the laboratory experiment a completely randomized design was used, adopting two treatments (with and without packaging coating with Tetra Pak(r)) with 15 repetitions (days). The experiment under field conditions was conducted in a swine nursery. The design was completely randomized, adopting two treatments with 12 repetitions. The treatments consisted of heated creep with and without Tetra Pak(r) lining. The data measured were ambient temperature, relative humidity, surface temperature of the floor, surface temperature of skin, behavior and weight gain of suckling piglets. The use of Tetra Pak(r) packaging as insulation in creep coating maintained the ambient temperature comfortable (32 °C), providing thermal comfort to suckling piglets.
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Animales , Aluminio/análisis , Embalaje de Productos , Temperatura , Animales Lactantes , PorcinosRESUMEN
The diagnostic image quality of contrast-enhanced (CE) 3D MR venography (MRV) was prospectively compared with that of 2D time-of-flight (TOF) MRV and contrast-enhanced 3D magnetization-prepared rapid acquisition of gradient echo (MPRAGE) sequences for the visualization of the intracranial venous system at 3T in 22 patients. CE MRV provides high-quality images and was shown to be superior to TOF MRV and MPRAGE sequences in visualizing the normal intracranial venous system.
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Venas Cerebrales/patología , Gadolinio DTPA , Aumento de la Imagen/métodos , Interpretación de Imagen Asistida por Computador/métodos , Angiografía por Resonancia Magnética/métodos , Trombosis de la Vena/patología , Adolescente , Adulto , Anciano , Medios de Contraste , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
PURPOSE: To investigate the impact of technical and morphological parameters on the precision of software-based MR tumor volumetry (SBV) in an in-vitro experimental setting. MATERIALS AND METHODS: Tumor models were formed from a silicone compound in three different sizes with a max. diameter < 2 cm (small), 2 - 4 cm (middle), and > 4 cm (large). For each size a spherical, an elliptic and an irregular shaped model was produced. The true volume of the tumor models was established by water displacement. Tumor models were examined with a high-field MRI (TRIO, 3 Tesla, Siemens) with T 2-weighted sequences under optimized contrast conditions. Slice thickness was 1, 3 and 5 mm. The volume of the tumor models was then calculated using (1). manually driven volumetric software (SBVmanual) and (2). automatic volumetric software (SBVauto). The influence of the following parameters on the precision of SBV was analyzed: Size and shape of the tumor models, manual/automatic SBV, segmentation technique and slice thickness. RESULTS: In general, SBVauto measurements showed less deviation than measurements with SBVmanual (p < 0.01). However, both methods depended significantly on morphologic factors, especially on tumor size. In small tumor models, the volume was strongly underestimated by -36.2 +/- 27.8 % (SBVmanual) and -33.1 +/- 8.6 % (SBVauto), whereas the deviation for large tumor models was only 2.0 +/- 14.7 % (SBVmanual) and 3.0 +/- 2.3 % (SBVauto; p < 0.01). The deviation of measurements increased from the "spherical" to the "irregular" shape by 9.5 % (SBVmanual) and 10.7 % (SBVauto). In addition, SBVmanual depended on technical factors. Using a "minimal" segmentation technique (e. g. excluding partial volume effects), volumes were underestimated in all cases, whereas volumes of middle and large tumor models were slightly overestimated when using a "maximum" segmentation technique (e. g. including partial volume effects; p = 0.01). Deviation of SBVmanual increased with slice thickness from 15.9 +/- 12.7 % (1 mm slices) to 27.1 +/- 21.3 % (5 mm-slices). CONCLUSION: In general, SBVauto measurements yielded smaller deviations than SBVmanual. However, both methods showed major inaccuracy in the volumetric estimation of small and irregular shaped tumor models, thus the tumor volumetry of these tumors has to be considered inappropriate for clinical practice. Moreover, the exactness of SBVmanual depended significantly on segmentation technique and slice thickness.
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Aumento de la Imagen/métodos , Interpretación de Imagen Asistida por Computador/métodos , Imagenología Tridimensional/métodos , Imagen por Resonancia Magnética/métodos , Neoplasias/patología , Humanos , Imagen por Resonancia Magnética/instrumentación , Fantasmas de Imagen , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
We studied the trigeminal nerve in seven healthy volunteers and six patients with trigeminal neuralgia using the diffusion tensor imaging derived parameter fractional anisotropy (FA). While controls did not show a difference between both sides, there was a reduction of FA in the affected nerve in three of six patients with accompanying nerve-vessel conflict and atrophy. Reversibility of abnormally low FA values was demonstrated in one patient successfully treated with microvascular decompression.
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Imagen de Difusión por Resonancia Magnética , Neuralgia del Trigémino/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Anisotropía , Mapeo Encefálico , Descompresión Quirúrgica/métodos , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Neuralgia del Trigémino/cirugíaRESUMEN
Preoperative fMRI is one of the best established clinical fMRI applications. Due to the difficulties in recording and coregistration of functional image data, we present methods to standardize and automate these procedures. We used a self-made interactive software package (AFI - Automated Functional Imaging) to automate the time consuming and complex analysis of fMRI data. AFI controls the BrainVoyager program, a postprocessing software package, and furthermore facilitates data management, anonymization of patient data, storage, documentation, data export to neuronavigation systems and the opportunity of spatial transformation of image data for use in group studies. By the end of 2006 we have used this method on 123 patients with brain tumors and 47 patients with trigeminal neuralgia. The fundamental basis of multimodal neuronavigation is precise coregistration. EPI images contain spatial distortions of 5-15 mm. We were able to reduce the misregistration of EPI and FLASH images in a selectable region of interest to 1-2 mm. Furthermore AFI reduces the average evaluation time for a standard clinical fMRI study (four functional measurements, one anatomical data set) by approx. 50% from 140 minutes to about 70 minutes in comparison to manual evaluation by an expert. More importantly, the personal attendance time required for the evaluation decreases by 84% to 23 minutes as the remainder of the program runs automatically. In comparison to currently available online postprocessing software tools which are more limited in use, BrainVoyager can be used for coregistration, data export to neuronavigation systems and spatial transformation.
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BACKGROUND AND PURPOSE: To assess the appearance of carotid artery stents at 3.0 Tesla contrast enhanced magnetic resonance angiography (CE-MRA) as compared with 1.5 Tesla. METHODS: 19 stents (GUIDANT Acculink, GUIDANT Dynalink, BOSTON SCIENTIFIC SMART Neuroform, GUIDANT Omnilink, EV3 Protege, BOSTON SCIENTIFIC Carotid Wallstent, ABBOTT Xact) of different materials (nitinol, stainless steal, cobalt alloy) and different sizes (4.0 mm-10.0 mm) were investigated regarding their appearance on CE-MRA at 3.0 Tesla and at 1.5 Tesla. For each stent artificial lumen narrowing (ALN) was calculated based on a pixel-by-pixel profile of the contrast-to-noise-ratio giving an objective indicator for the size of the evaluable stent diameter. RESULTS: Only in two stents (Omnilink 7.0 mm, Omnilink 10.0 mm) was ALN higher at 3.0 Tesla relative to 1.5 Tesla. In all other stents ALN at 3.0 Tesla was the same or even lower as compared with 1.5 Tesla. In contrast to the ferromagnetic stents where ALN was typically higher than 85%, in most of the nitinol stents (Acculink, Dynalink, Neuroform, Protege) ALN was below 35%. In the Xact stents ALN was generally 100% at 1.5 Tesla and ranged between 31.8% and 100% at 3.0 Tesla. CONCLUSION: CE-MRA after carotid artery stenting is considerably impaired by ALN both at 1.5 Tesla and at 3.0 Tesla. Nevertheless, CE-MRA is well suited for the examination of carotid artery stents made of nitinol at both field strengths. Stent manufacturers should be aware of potential artifacts caused by their stents during noninvasive diagnostic methods such as CE-MRA.
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Arterias Carótidas , Angiografía por Resonancia Magnética/métodos , Stents , Aleaciones , Artefactos , Cobalto , Medios de Contraste , Humanos , Técnicas In Vitro , Fantasmas de Imagen , Acero Inoxidable , Accidente Cerebrovascular/prevención & controlRESUMEN
PURPOSE: To assess prospectively how often contacts are found between the trigeminal nerve and arteries or veins in the perimesencephalic cistern via MRI in normal volunteers. MATERIALS AND METHODS: 48 volunteers without a history of trigeminal neuralgia were examined prospectively (MRI at 1.5 T; T2-CISS sequence, coronal orientation, 0.9 mm slice thickness). Two radiologists decided by consensus whether there was a nerve-vessel contact in the perimesencephalic cistern. RESULTS: In 27 % of the volunteers, no contact was found between the trigeminal nerve and regional vessels, while in 73 %, such a contact was present. In 61 % of the cases, the offending vessel was an artery, in 39 %, it was a vein. In 2 volunteers, a deformation of the nerve was noted. CONCLUSION: Contrary to what has been suggested by retrospective studies, the majority of normal volunteers, if studied prospectively, do show a contact between the trigeminal nerve and local vessels. A close proximity between the nerve and regional vessels is thus normal and is not necessarily proof of a pathological nerve-vessel conflict.
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Imagen por Resonancia Magnética/métodos , Síndromes de Compresión Nerviosa/diagnóstico , Nervio Trigémino/anatomía & histología , Neuralgia del Trigémino/diagnóstico , Adulto , Arterias/anatomía & histología , Vasos Sanguíneos/anatomía & histología , Cerebelo/irrigación sanguínea , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Estudios Retrospectivos , Neuralgia del Trigémino/etiologíaRESUMEN
Infectious diseases of the central nervous system have often to be considered in differential diagnosis, particularly in immunocompromised persons. Neuroimaging, specifically advanced techniques such as diffusion-weighted MRI and perfusion MRI contribute much to the differentiation of various brain infections and to delineation of brain infections from other, for instance, neoplastic diseases. In this review we present the imaging criteria for the most important brain infections in adults and discuss in detail differential diagnostic aspects.
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Encefalopatías/diagnóstico por imagen , Encefalopatías/patología , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Infecciones del Sistema Nervioso Central/diagnóstico por imagen , Infecciones del Sistema Nervioso Central/patología , Imagen por Resonancia Magnética/métodos , Tomografía Computarizada por Rayos X/métodos , Adulto , Diagnóstico Diferencial , Humanos , Guías de Práctica Clínica como Asunto , Pautas de la Práctica en MedicinaRESUMEN
BACKGROUND: Spinal cord stimulation (SCS) is an effective alternative treatment in patients with chronic neuropathic pain and mainly radicular distribution. The aim of this prospective study was to investigate changes in BOLD signal with fMRI during active SCS and to correlate the results with the clinical pain intensity, measured with a visual analogue scale (VAS). PATIENTS AND METHODS: Three patients with failed back surgery syndrome were tested during the clinical trial of SCS. A first fMRI was performed with marked pain and a high VAS score. Before the second fMRI a therapeutic stimulation phase with pain reduction was carried out. RESULTS: With high pain levels SCS activated the cingulate gyrus, thalamus, prefrontal cortex, supplementary motor area and postcentral gyrus. After pain reduction, SCS did not elicit these activations in the second fMRI, using the same stimulation parameters. CONCLUSIONS: In patients with chronic neuropathic pain and high VAS levels, SCS elicited BOLD activation in the cingulate gyrus, thalamus, prefrontal cortex, and primary and secondary somatosensory area. Pain reduction by SCS resulted in a reduction of functional activity in these areas as revealed by follow-up fMRI.
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Neuralgia/terapia , Procedimientos Neuroquirúrgicos/métodos , Dolor Postoperatorio/fisiopatología , Médula Espinal/fisiopatología , Terapia por Estimulación Eléctrica , Lateralidad Funcional , Humanos , Imagen por Resonancia Magnética , Neuralgia/diagnóstico , Dolor Postoperatorio/diagnóstico , SíndromeRESUMEN
PURPOSE: Functional magnetic resonance imaging (fMRI) localizes Broca's area (B) and Wernicke's area (W) and the hemisphere dominant for language. In clinical fMRI, adapting the stimulation paradigms to each patient's individual cognitive capacity is crucial for diagnostic success. To interpret clinical fMRI findings correctly, we studied the effect of varying frequency and number of stimuli on functional localization, determination of language dominance and BOLD signals. MATERIALS AND METHODS: Ten volunteers (VP) were investigated at 1.5 Tesla during visually triggered sentence generation using a standardized block design. In four different measurements, the stimuli were presented to each VP with frequencies of 1/1 s, (1/2) s, (1/3) s and (1/6) s. RESULTS: The functional localizations and the correlations of the measured BOLD signals to the applied hemodynamic reference function (r) were almost independent from frequency and number of the stimuli in both hemispheres, whereas the relative BOLD signal changes (DeltaS) in B and W increased with the stimulation rate, which also changed the lateralization indices. The strongest BOLD activations were achieved with the highest stimulation rate or with the maximum language production task, respectively. CONCLUSION: The adaptation of language paradigms necessary in clinical fMRI does not alter the functional localizations but changes the BOLD signals and language lateralization which should not be attributed to the underlying brain pathology.
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Mapeo Encefálico , Lóbulo Frontal/fisiología , Lenguaje , Imagen por Resonancia Magnética/métodos , Lóbulo Temporal/fisiología , Adulto , Femenino , Lateralidad Funcional , Hemodinámica , Humanos , Masculino , Persona de Mediana Edad , Estimulación Luminosa , Factores de TiempoAsunto(s)
Ácido Aspártico/análogos & derivados , Corteza Cerebelosa/patología , Imagen por Resonancia Magnética , Degeneraciones Espinocerebelosas/patología , Ácido Aspártico/deficiencia , Corteza Cerebelosa/química , Corteza Cerebral/química , Niño , Preescolar , Consanguinidad , Diagnóstico Diferencial , Femenino , Humanos , Lactante , Inositol/análisis , Imagen por Resonancia Magnética/métodos , Espectroscopía de Resonancia Magnética , Masculino , Distrofias Neuroaxonales/diagnóstico , Degeneraciones Espinocerebelosas/diagnóstico , Degeneraciones Espinocerebelosas/metabolismoRESUMEN
OBJECTIVES: To assess whether it is possible to measure tooth vitality using magnetic resonance imaging (MRI). METHODS: Signal intensity measurements were conducted using T(1) and T(2) sequences at the region of interest in 211 teeth (35 patients). RESULTS: Clinical findings showed that 17.3% of the teeth were avital, whereas 82.7% were found to be vital. Neither the T(2) sequence nor the non-contrast-enhanced T(1) sequence showed significant differences between vital and avital teeth. However, the contrast-enhanced sequence and, in particular, a comparison of signal intensities between the non-contrast-enhanced T(1) sequence and the contrast-enhanced sequence showed a significant difference between vital and avital teeth. CONCLUSION: Contrast-enhanced MRI enables us to draw conclusions on pulpal perfusion in vivo.
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Pulpa Dental/fisiología , Imagen por Resonancia Magnética , Adolescente , Adulto , Anciano , Medios de Contraste , Pulpa Dental/irrigación sanguínea , Prueba de la Pulpa Dental , Reacciones Falso Negativas , Reacciones Falso Positivas , Femenino , Humanos , Aumento de la Imagen , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Diente no Vital/diagnósticoRESUMEN
Our aim was to determine whether CT angiography is suitable for the evaluation of in-stent restenoses in small vessel stents for intracranial angioplasty. Therefore, we simulated stenoses with degrees of 25, 50, 75 and 90% in a total of 12 stents with different designs (MEDTRONIC AVE; ABBOT BioDivYsio, GUIDANT Neurolink, TERUMO Tsunami, COOK V-Flex Plus) and sizes (3.0 mm, 4.0 mm). For each stenosis, the apparent stenotic degree (ASD) was measured by CT angiography. Subjective (viewing at the CT images) and objective (acquisition of a density profile) evaluations were made after the stents were filled with a solution of 0.9% NaCl and with a diluted contrast medium. It was not possible to visualize the patent lumen in any of the stenotic stent segments by viewing at the CT images. After objective evaluation, the degree of the stenoses was generally overestimated. In the group with the 3.0-mm stents, ASD ranged from 73.6 to 100% in 25% degree stenoses. With the exception of one stent, stenoses with a degree of more than 25% appeared as vessel obstruction (ASD = 100%) in the 3.0-mm group. In the 4.0-mm group, the mean ASD was 60% for 25% degree stenoses, 76% for 50% degree stenoses, 91% for 75% degree stenoses and 96% for 95% degree stenoses. The minimum diameter of stents for differentiation between in-stent restenosis and vessel occlusion using CT angiography is 4.0 mm. In CT angiography, the degrees of in-stent stenoses are generally overestimated. The evaluation of in-stent restenoses only seems to be possible when CT angiographic images before and after contrast application are evaluated objectively by density profiles.
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Angioplastia de Balón , Angiografía Cerebral , Stents , Tomografía Computarizada por Rayos X , Constricción Patológica/terapia , Diseño de Equipo , Humanos , Enfermedades Arteriales Intracraneales/terapiaRESUMEN
PURPOSE: To assess whether MRI can detect atrophy of the trigeminal nerve in patients with trigeminal neuralgia. MATERIALS AND METHODS: A prospective MRI study was conducted in 39 patients (trigeminal neuralgia, trigeminal neuropathy, or atypical facial pain) and 25 volunteers. Using a coronal orientation (T1 Flash 3D; T2 CISS 3D), regions of interest were delineated in the cisternal part of the trigeminal nerve along the border of the nerve to calculate the volume of the nerve. The volume of the nerve was compared side-by-side in each patient (t-test, p < 0.05) and the volume difference compared between patients and volunteers. RESULTS: The volume of the compromised trigeminal nerve in patients with trigeminal neuralgia was lower than on the contralateral healthy side, with the difference between healthy and compromised side statistically significant (p < 0.05). In all other patients and in all volunteers, no significant difference was found between the volume of the healthy and compromised nerve. The volume difference between the healthy and compromised side in patients with trigeminal neuralgia was significantly higher (p < 0.05) than in all other patients and volunteers. CONCLUSION: Atrophy of the trigeminal nerve caused by a nerve-vessel conflict can be detected by MRI. Only patients with trigeminal neuralgia show this unilateral atrophy. Therefore, it is possible to demonstrate the result of the nerve-vessel conflict and to determine the consequences of such a conflict.
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Imagen por Resonancia Magnética/métodos , Nervio Trigémino/patología , Neuralgia del Trigémino/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Atrofia , Interpretación Estadística de Datos , Diagnóstico Diferencial , Femenino , Humanos , Masculino , Persona de Mediana Edad , Enfermedades del Nervio Trigémino/diagnóstico , Enfermedades del Nervio Trigémino/patología , Neuralgia del Trigémino/patologíaRESUMEN
Diseases of the mandible affect the soft tissues aside from the osseous manifestation. This can be shown clearly and in great detail by magnetic resonance imaging (MRI). MRI is the gold standard in the diagnostic evaluation of any internal derangement of the temporomandibular joint. Dental MRI requires high resolution techniques and in some cases also intravenous administration of contrast material. These techniques allow delineation of the neurovascular bundle. In the past few years new indications were formulated, for example, the evaluation of the integrity of the inferior alveolar nerve in trauma and in radicular cysts. New quantitative methods now enable insights into the pathophysiology. The objective of this review is to communicate accepted indications for MRI of the mandible and to present innovative applications.
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Imagen por Resonancia Magnética , Enfermedades Mandibulares/diagnóstico , Enfermedades de la Boca/diagnóstico , Enfermedades Dentales/diagnóstico , Medios de Contraste , Pulpa Dental , Diagnóstico Diferencial , Humanos , Imagen por Resonancia Magnética/métodos , Enfermedades Mandibulares/diagnóstico por imagen , Fracturas Mandibulares/diagnóstico , Absceso Periapical/diagnóstico , Quiste Radicular/diagnóstico , Trastornos de la Articulación Temporomandibular/diagnóstico , Tomografía Computarizada por Rayos X , Traumatismos del Nervio TrigéminoRESUMEN
Statistically tumors are the most likely cause of space-occupying intracranial lesions. However, many non-neoplastic diseases also manifest as mass lesions and may be indistinguishable from tumors. The most common of these are inflammatory and dysplastic lesions, which intraaxially imitate mostly glioma, lymphoma, and metastases and extraaxially meningeoma and neurinoma. Aside from a willingness on the part of the diagnostic radiologist to question the most obvious diagnosis, on clinical history and findings are prerequisites for a sound radiological differential diagnosis. The aim of this article is to provide a practical overview of the differential diagnosis of intracranial mass lesions with emphasis on non-neoplastic abnormalities.
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Encefalopatías/diagnóstico , Neoplasias Encefálicas/diagnóstico , Trastornos Cerebrovasculares/diagnóstico , Imagen por Resonancia Magnética , Adulto , Hemorragia Cerebral/diagnóstico , Infarto Cerebral/diagnóstico , Diagnóstico Diferencial , Encefalitis/diagnóstico , Granulomatosis con Poliangitis/diagnóstico , Humanos , Neurocisticercosis/diagnóstico , Enfermedades de la Hipófisis/diagnósticoRESUMEN
The objective of this study was to assess whether signal changes can be detected in the neurovascular bundle of the mandibular canal after the extraction of a third molar. We retrospectively analyzed MRI scans of 30 test subjects with healthy mandibles and 41 patients who had had a wisdom tooth extracted. Signal intensities were measured at particular sites in the neurovascular bundle, which were defined as regions of interest (ROI) in the sagittal T1-weighted images before and after intravenous administration of a paramagnetic contrast agent. On the basis of the signal intensity increases that were measured after contrast agent administration, we compared the signal increases obtained for the patients who had received surgical treatment with the results obtained for the population of test subjects with unremarkable mandibles ( t-test, P<0.05). Compared with the healthy test subjects, patients who had received surgical treatment showed significantly higher signal intensity increases at two measurement sites, i.e., the second molar and the second premolar ( P<0.05). We found no significant differences when the measurements were performed at the first molar ( P=0.06), the third molar ( P=0.47) and in the area of the ascending mandibular ramus ( P=0.79). Compared with a population of healthy test subjects, patients who had their third molars surgically removed show higher signal intensity increases in the neurovascular bundle after intravenous contrast agent administration. The underlying cause may be the higher blood flow in the arteries and veins and the perineural plexus, which may give evidence of the pathophysiological mechanism of nerve damage in the narrow canal as a result of osteotomy.
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Imagen por Resonancia Magnética/métodos , Mandíbula/inervación , Nervio Mandibular/fisiopatología , Tercer Molar/cirugía , Extracción Dental , Adolescente , Adulto , Medios de Contraste/administración & dosificación , Femenino , Humanos , Masculino , Mandíbula/patología , Nervio Mandibular/fisiología , Persona de Mediana Edad , Periodo Posoperatorio , Valores de Referencia , Estudios RetrospectivosRESUMEN
Necrotic meningiomas are relatively rare, accounting for 1.3-3.9% of primary intracranial tumours and for 10-15% of meningiomas, but are of special clinical importance as they may resemble metastases or malignant gliomas. We report the magnetic resonance findings of diffusion-weighted imaging, perfusion-weighted imaging, and spectroscopy in a patient with a necrotic meningioma, in whom clinical symptoms and signs suggested a central nervous system infection.
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Encéfalo/patología , Imagen de Difusión por Resonancia Magnética , Espectroscopía de Resonancia Magnética , Neoplasias Meníngeas/diagnóstico , Meningioma/diagnóstico , Adulto , Encéfalo/diagnóstico por imagen , Femenino , Humanos , Necrosis , Tomografía Computarizada por Rayos XRESUMEN
The objective of this study was to evaluate signal intensity increases in the greater petrosal nerve after contrast agent administration to gather information on the etiology of idiopathic peripheral facial paralysis. Magnetic resonance images were obtained from 18 patients who received inpatient medical treatment for acute peripheral facial nerve palsy. Images of intratemporal segments of the facial nerve were taken with a slice thickness of 0.75 mm. After multiplanar reconstruction, regions of interest (ROI) were defined in the proximal segment of the greater petrosal nerve. After multiplanar reconstruction, it was possible to visualize the greater petrosal nerves of all 18 patients. The nerve's average diameter was found to be 0.68 mm (range 0.5-0.9). Signal intensity increased by an average of 50.3% (range -10-146%) after contrast agent administration. Whereas this intensity was slightly reduced in two patients, it was increased in 16. No correlation could be established between greater signal intensity and medical history, clinical condition, laboratory findings, or electrophysiological data. In contrast to quantitative measurements in the facial nerve, ROI measurements in the greater petrosal nerve do not correlate with medical history, clinical condition, or laboratory findings. For this reason, MRI of this nerve does not enable us to draw conclusions on the etiology of idiopathic peripheral facial paralysis.