RESUMEN
A humanoid thorax phantom containing six compartments was scanned with two different computed tomography (CT) scanners using various image acquisition and reconstruction parameters. The differences of CT numbers were statistically significant between the two CT scanners for each compartment (p<0.001) except for the "air" compartment. The variabilities of the CT numbers are described for the different parameters. The mean CT numbers of the "water" compartment, for instance, ranged from 1 to 15HU (Hounsfield Units), those of the "air" compartment varied from -962 to -990HU. Knowledge of these CT number variabilities is necessary when CT numbers are used for tissue characterization.
Asunto(s)
Procesamiento de Imagen Asistido por Computador/métodos , Fantasmas de Imagen , Radiografía Torácica , Tomógrafos Computarizados por Rayos X , Tomografía Computarizada por Rayos X/métodos , Aire , Algoritmos , Artefactos , Huesos , Humanos , Pulmón , Dosis de Radiación , Procesamiento de Señales Asistido por Computador , Tomógrafos Computarizados por Rayos X/estadística & datos numéricos , AguaRESUMEN
We investigated a method for a fully automatic identification and interpretation process for clustered microcalcifications in mammograms. Mammographic films of 100 patients containing microcalcifications with known histology were digitized and preprocessed using standard techniques. Microcalcifications detected by an artificial neural network (ANN) were clustered and some cluster features served as the input of another ANN trained to differentiate between typical and atypical clusters, while others were fed into an ANN trained on typical clusters to evaluate these lesions. The measured sensitivity for the detection of grouped microcalcifications was 0.98. For the task of differentiation between typical and atypical clusters an Az value of 0.87 was computed, while for the diagnosis an Az value of 0.87 with a sensitivity of 0.97 and a specificity of 0.47 was obtained. The results show that a fully automatic computer system was developed for the identification and interpretation of clustered microcalcitications in mammograms with the ability to differentiate most benign lesions from malignant ones in an automatically selected subset of cases.
Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Calcinosis/diagnóstico por imagen , Diagnóstico por Computador , Mamografía/métodos , Enfermedades de la Mama/diagnóstico por imagen , Errores Diagnósticos , Estudios de Evaluación como Asunto , Femenino , Humanos , Mamografía/estadística & datos numéricos , Redes Neurales de la Computación , Diseño de SoftwareAsunto(s)
Encéfalo/irrigación sanguínea , Interpretación de Imagen Radiográfica Asistida por Computador/instrumentación , Tomografía Computarizada por Rayos X/instrumentación , Velocidad del Flujo Sanguíneo/fisiología , Medios de Contraste , Humanos , Sensibilidad y Especificidad , Programas InformáticosAsunto(s)
Encéfalo/irrigación sanguínea , Tomografía Computarizada por Rayos X/instrumentación , Algoritmos , Velocidad del Flujo Sanguíneo/fisiología , Volumen Sanguíneo/fisiología , Estenosis Carotídea/diagnóstico , Estenosis Carotídea/fisiopatología , Medios de Contraste , Dominancia Cerebral/fisiología , Humanos , Masculino , Microcomputadores , Persona de Mediana EdadRESUMEN
We present a new technique of image fusion (IF) of magnetic resonance imaging (MRT) and anti-CEA-immunoscintigraphy (Behring 431/26) and single photon emission computed tomography (SPECT). We performed SPECT and MRT within 8 hours on the same day. Glucagon intravenously was used to reduce artefacts due to intestinal motility. Before image fusion we analysed the SPECT and MRT images independently of each other. The MRT and SPECT were connected by a local area network (LAN) to a Gateway computer, which is also used as a picture archive. There a program automatically starts, translates the MRT data from the ACR/NEMA format to the Elscint one and these data are sent for image fusion to the nuclear medicine computer Elscint SP1. By means of a clinical example we present anatomic concordant superimposition and explain the findings and the clinical value of our technique. This system and technique are equally applicable to other digital imaging investigations. By IF, on the basis of the certain evidence of the tracer depot of a pathological lesion diagnosed by MRT and the reliability of the anatomical assignment of a focal lesion diagnosed by SPECT, early detection of local recurrence after surgical treatment of rectal cancer, the correct localisation of recurrent disease and its distinction from non-malignant tissue becomes possible. This enables planning of further therapeutical strategies.
Asunto(s)
Adenocarcinoma/cirugía , Antígeno Carcinoembrionario/inmunología , Procesamiento de Imagen Asistido por Computador/instrumentación , Imagen por Resonancia Magnética/instrumentación , Recurrencia Local de Neoplasia/diagnóstico , Radioinmunodetección , Neoplasias del Recto/cirugía , Tomografía Computarizada de Emisión de Fotón Único/instrumentación , Adenocarcinoma/diagnóstico , Adulto , Humanos , Aumento de la Imagen/instrumentación , Redes de Área Local/instrumentación , Escisión del Ganglio Linfático , Metástasis Linfática , Masculino , Recurrencia Local de Neoplasia/cirugía , Neoplasias del Recto/diagnóstico , ReoperaciónRESUMEN
In this report we present an integrated picture archiving and communication system (PACS)--radiology information system (RIS) which runs as part of the daily routine in the Department of Radiology at the University of Graz. Although the PACS and the RIS have been developed independently, the two systems are interfaced to ensure a unified and consistent long-term archive. The configuration connects four computer tomography scanners (one of them situated at a distance of 1 km), a magnetic resonance imaging scanner, a digital subtraction angiography unit, an evaluation console, a diagnostic console, an image display console, an archive with two optical disk drives, and several RIS terminals. The configuration allows the routine archiving of all examinations on optical disks independent of reporting. The management of the optical disks is performed by the RIS. Images can be selected for retrieval via the RIS by using patient identification or medical criteria. A special software process (PACS-MONITOR) enables the user to survey and manage image communication, archiving, and retrieval as well as to get information about the status of the system at any time and handle the different procedures in the PACS. The system is active 24 hours a day. To make the PACS operation as independent as possible from the permanent presence of a system manager (electronic data processing expert), a rule-based expert system (OPERAS; OPERating ASsistant) is in use to localize and eliminate malfunctions that occur during routine work. The PACS-RIS reduces labor and speeds access to images within radiology and clinical departments.