ABSTRACT
OBJECTIVES: The aim was to define image quality and radiation exposure in the recently introduced 320-row CT of the temporal bone (tb) in comparison to a 16-row tb CT. METHODS: A cadaveric head phantom was used for repeated tb volume CT studies (80-120 kV, 25-150 mAs), performed in a 320-row scanner (single rotation, 0.5 mm slice thickness, kernel FC 51) in comparison to 16-row helical CT using standard acquisition parameters (SAP) of 120 kV and 75 mAs (kernel FC 53). Qualitative image evaluation was performed by two radiologists using a 5-point visual analogue scale. Image noise (D(SD)) was determined by region of interest (ROI) based measurements in cadaveric as well as water phantom studies. Dosimetric measurements of the effective dose (ED) and organ dose (OD) of the lens were performed. RESULTS: Image quality of 320-row tb CT was equivalent to 16-row CT for SAP scans, resulting in image noise levels (D(SD) 16-/320-row) of 109/237 and 206/446 for air and bone respectively. D(SD) differences were predominantly (>90%) attributable to the different kernels available for tb studies in 16- and 320-row CT. Radiation exposure for 16-/320-row SAP scans amounted to 0.36/0.30 mSv (ED) and 10.0/8.4 mGy (lens dose). CONCLUSION: 320-row volume acquisition in tb CT delivers equivalent image quality to 16-row CT while decreasing radiation exposure figures by one sixth. Image noise increase in 320-row CT is negligible with respect to image quality.
Subject(s)
Image Processing, Computer-Assisted/methods , Radiation Dosage , Radiographic Image Enhancement/methods , Temporal Bone/diagnostic imaging , Tomography, X-Ray Computed/methods , Artifacts , Cadaver , Ear Canal/diagnostic imaging , Ear Ossicles/diagnostic imaging , Ear, Inner/diagnostic imaging , Ear, Middle/diagnostic imaging , Humans , Mastoid/diagnostic imaging , Phantoms, Imaging , Radiology Information Systems , Temporal Bone/radiation effects , Tomography, Spiral Computed/methodsABSTRACT
PURPOSE: To define the role of olfactory bulb volume measurement by magnetic resonance imaging (MRI) for detecting olfactory dysfunction in comparison with objective olfactometry. MATERIALS AND METHODS: Thirty patients with suspected olfactory dysfunction (16 women, 14 men; mean age 52 years, range 20 - 79 years) were examined by MRI and objective olfactometry between January 2006 and January 2009. Olfactory bulb volumes were measured by two neuroradiologists using 3D MR data sets. The olfactory function was categorized as normosmia, hyposmia, and anosmia on the basis of objective olfactometry. Pearson correlation coefficients were calculated for objective olfactometry and olfactory bulb volumes on MRI. ROC analysis was performed to determine whether MRI bulb volumes can serve to predict anosmia or hyposmia. RESULTS: The bulb volumes measured by MRI ranged from 0 to 135.9 mm (3). Based on olfactometry, anosmia was present in 11 patients (total bulb volume of 15.7 +/- 23.3 mm (3)), hyposmia in 9 patients (total bulb volume of 50.0 +/- 25.5 mm (3)), and normosmia in 10 patients (total bulb volume of 110.7 +/- 21.5 mm (3)). There was good correlation (r > 0.9) between objective olfactometry and olfactory bulb volume on MRI. ROC analysis yielded a cut-off value of 32 mm (3) for anosmia, which had a sensitivity of 0.91 and specificity of 0.947. The cut-off value for olfactory dysfunction was 80.7 mm (3) (sensitivity 0.95; specificity of 0.9). CONCLUSION: The olfactory bulb volume determined by MRI is a suitable parameter for diagnosing complete or partial loss of the sense of smell.
Subject(s)
Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Olfaction Disorders/diagnosis , Olfactory Bulb/pathology , Sensory Thresholds/physiology , Adult , Aged , Atrophy , Dominance, Cerebral/physiology , Female , Humans , Male , Middle Aged , Odorants , Organ Size/physiology , ROC Curve , Reference Values , Statistics as Topic , Young AdultABSTRACT
BACKGROUND: Investigations into the MRI compatibility of middle ear implants made from titanium alloys with 1.5 and 3.0 tesla MRI systems which are frequently used for imaging diagnostics. METHOD: 17 different middle ear (ME) implants (ossicular replacement prosthesis (ORP) and ventilation tubes) made from titanium were tested in vitro. Potential warming was determined via an MRI-compatible fibre optic temperature sensor under the influence of sequences with high-level high frequency impulses. An assessment of the attractive force of the implants was carried out placed on a Petri dish under vibration and floating on rubber-sponge (RS) in a water bath. RESULTS: No significant warming of the implants was observed with any of the used sequences at either 3 or 1.5 Tesla field strength (TF). With 3 TF, all 17 implants changed their position on the surface of the water and moved at a slow speed (0.0004-0.0014 m/s) towards the magnetic field. With 1.5 TF, the tested ME implants moved at a maximum speed of 0.0002 m/s and in the case of the ventilation tubes at 0.0005 m/s. CONCLUSION: No warming occurred in any of the tested middle ear implants at either 1.5 or 3 TF. The attractive forces exerted through the static magnetic field were overall low at 1.5 and 3 TF, indicating that no dislocation is to be expected if intraoperative anchoring is correctly conducted. Nevertheless, the indication for examination at 3 TF should be carefully considered due to the anatomically sensitive region.
Subject(s)
Magnetic Resonance Imaging , Middle Ear Ventilation/instrumentation , Ossicular Prosthesis , Titanium , Contraindications , Electromagnetic Fields/adverse effects , Equipment Failure Analysis , Equipment Safety , Humans , In Vitro Techniques , Magnetic Resonance Imaging/instrumentation , TemperatureABSTRACT
Se describe la experiencia obtenida en el hospital docente "General Calixto Garcia" acerca de las lesiones toracicas de los politraumatizados y se hace un analisis especial de los traumatismos oseos de la pared toracica basado en dicha experiencia con 115 pacientes hospitalizados en 1978, y 79 en 1981. El 51,6% de los traumatismos del torax en hospitalizados en nuestro servicio ocurrieron en politraumatizados.El 73,2% se preto en pacientes que estaban entre los 21 y 60 anos de edad, y el 79,7% en el sexo masculino. Las causas mas frecuentes de estos traumatismos fueron los accidentes del transito y las precipitaciones o caidas. Hubo lesiones de la pared toracica en el 88,2% de los politraumatizados, y el 16,3% de ellos tenia tambien lesiones viscerales del torax. Las lesiones mas frecuentemente asociadas a los traumatismos toracicos fueron las craneoencefalicas y tambien las que mas contribuyeron a la mortalidad. La mortalidad general en los politraumatizados con lesiones toracicas oscilo entre el 12,2% y el 12,7% y fue nueve veces superior a la ocurrida en los pacientes con traumatismos aislados del torax. Las lesiones del esqueleto del torax que mayor mortalidad produjeron, fueron el torax batiente y la fractura del esternon
