RESUMEN
A new type of terminal device, a wireless personal digital assistant (PDA) based on a GSM digital cellular phone, was used to transmit computerized tomography scans of 21 patients to a neuroradiologist. All transmitted images were suitable for a preliminary consultation and in one case a final report could be made. In 18 cases the findings were compatible with the reference film reading performed later and in three cases there were minor differences of no clinical importance. Transmission of a single image lasted 1 min 30 s and the transmission of a complete brain scan (14 images) took on average 21 min. The total process of transmission and interpretation of a brain examination series took on average 40 min. In this pilot study the neuroradiologist gained essential information in 24% of the cases and beneficial information in 62%. The neuroradiologist considered that the image consultation saved a hospital visit in 15 cases (71%). Although PDA technology is at an early stage of development and has numerous limitations, it is likely that future technical improvements will allow easier clinical consultations for neurosurgeons and neurologists.
Asunto(s)
Telerradiología/normas , Tomografía Computarizada por Rayos X/normas , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Lesiones Encefálicas/diagnóstico , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Intensificación de Imagen Radiográfica/normas , Telerradiología/instrumentaciónRESUMEN
OBJECTIVE: Seed filling in view lattice is a method for accelerating volume rendering. Our previously published results on using seed filling had the limitation that they did not support cut planes. Cut planes are one of the main advantages of using volume rendering over surface rendering. In this article we describe the seed-filling acceleration technique and propose two fast reseeding processes that may be performed for each frame. MATERIALS AND METHODS: The reseeding process performs a connected component search on the cut plane within the volume data set. The amount of processing done by a connected component search algorithm is proportional to N(2), assuming the data set size is N(3). We implemented two connected component search algorithms: one for orthogonal cut planes and another for oblique cut planes. We measured the time taken by the cutting and estimated the effect on the rendering performance when the cut plane was moved interactively. RESULTS: Our measurements show that rendering rates of several frames per second can be achieved with a 266-MHz Pentium II PC, even when the object is interactively modified with cut planes during the rendering. CONCLUSIONS: We have shown that the seed-filling algorithm is also applicable in situations where the displayed data is modified interactively using cut planes or objects. Applications in this regard include, for example, computer-aided surgery systems, where the instrument may be used to interactively perform the simulated cut in the data set.
Asunto(s)
Algoritmos , Gráficos por Computador , Procesamiento de Imagen Asistido por Computador , Animales , Encéfalo/anatomía & histología , Sistemas de Computación , Cabeza/anatomía & histología , Humanos , Procesamiento de Imagen Asistido por Computador/instrumentación , Imagen por Resonancia Magnética/instrumentación , Técnicas Estereotáxicas/instrumentación , Porcinos , Factores de Tiempo , Tomografía Computarizada por Rayos X/instrumentaciónRESUMEN
A wireless system for radiological subspecialist consultation based on a portable personal computer and a GSM cellular phone was tested. A link with secure access to the hospital image network was built. A total of 68 emergency computerized tomography (CT) examinations were transmitted. Transmission time via GSM for a single CT image was 1 min and for a complete head scan was 18 min. The transmitted images were acceptable for final diagnosis in 72% of the cases, the rest being acceptable for preliminary diagnosis. The diagnosis from the transmitted images did not change after a later review of the original images in 97% of cases. The wireless link saved a hospital visit by the senior radiologist in 24% of cases. The results show that a remote consultation link can be built with readily available technology and that the technique is useful in radiological subspecialist consultations for CT images.
Asunto(s)
Tratamiento de Urgencia , Microcomputadores , Telerradiología/métodos , Heridas y Lesiones/diagnóstico por imagen , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Sensibilidad y Especificidad , Telerradiología/instrumentación , Tomografía Computarizada por Rayos XRESUMEN
Rapid prototyping (RP) technique allows automatic fabrication of 3D model parts. This method was applied to make a temporal bone model before cochlear implant surgery. A helical CT scan is used to acquire high resolution data from the middle and the inner ear of the patient. From the scanning data bone structures and soft tissues can be separated because their different grayscale pixel values. By using a guided image processing tool the desired parts of the anatomy can be extracted and 3D data created. The segmented data are processed to the form suitable for creating a high accuracy RP model. The RP model is made in the stereolithography (SLA) process by means of a computer guided HeCd laser beam inducing polymerisation of acrylic solution as it passes layer by layer over the surface of the polymer solution. In this prototype model the anatomy of the temporal bone can be clearly visualised, including, e.g., mastoid cells, tympanic cavity, bony canal of facial nerve, and round and oval windows. The inner ear spaces including vestibule, semicircular canals and cochlear turn are also shaped. The transparent acrylic material allows bonelike mechanical handling. The RP model can be dissected and used in individual surgical planning and simulation prior to cochlear implantation.
Asunto(s)
Implantes Cocleares , Simulación por Computador , Procesamiento de Imagen Asistido por Computador/métodos , Hueso Temporal/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Humanos , Masculino , Persona de Mediana Edad , Modelos Anatómicos , Hueso Temporal/anatomía & histologíaRESUMEN
Respiratory gating during imaging to reduce imaging artifacts involves the gathering of image data only at the end of the respiratory cycle. This is commonly performed by a pneumatic respiratory belt to monitor thoracic wall motion during respiration. Such gating has been used for magnetic resonance, computerized tomographic, and nuclear medicine imaging. The goal of this study was to measure the performance of a standard belt used for gating imaging studies. The standard respiratory belt system provided with the Magnetom 42 SP MRI scanner (Siemens AG, Erlangen, Germany) was selected. The belt was connected to a microcontroller-based pressure measurement unit that was connected to the standard RS-232C serial port of a computer. The signal was compared with that of a strain gauge respiration transducer. The response of the system was tested in vitro both for isometric and isotonic loading. The data measured from the pneumatic belt was linear with different weights of 50 to 1,400 grams with a coefficient of determination (R2) of 0.999. The system was linear for different amounts of stretching (R2 of 0.998) within the first 45 mm, which is enough for normal breathing. In vivo the pneumatic system seemed more accurate in measuring the constant stretching in apnea than the strain gauge respiratory belt. The results show that it is possible to use a standard pneumatic belt for accurate measurement of thoracic wall movement during imaging and for other purposes as well.