RESUMEN
BACKGROUND: The aim of this retrospective analysis was to evaluate mammographic changes such as fat necroses and parenchymal scarring in the breast tissue within the first 3 years after breast-conserving surgery (BCS) and whole-breast irradiation with an additional intraoperative electron boost (IO-B) versus fractionated percutaneous boost (FP-B). METHODS: A total of 53 breast cancer patients (stage I/II) treated between 2006 and 2008 were included. All patients underwent BCS followed by fractionated whole-breast radiotherapy with a total dose and single dose of 50.4 and 1.8 Gy. Twenty patients had 10 Gy IO-B using electrons, and 33 patients were treated with a FP-B with 10.8 Gy. The IO-B was performed using the mobile linear accelerator NOVAC 7. The follow-up mammograms were focused on fat necroses, parenchymal scarring and skin thickening. RESULTS: Fat necroses occurred significantly more frequently in IO-B patients compared to FP-B patients (50.0 vs. 18.2 %). The fat necroses were mammographically detected a median of 17 versus 23 months post-surgery for the IO-B versus FP-B patients. The median size of fat necroses was 24 (14-30) mm for the IO-B group and 14 (4-53) mm for the FP-B group. Parenchymal scarring in the grade 3-4 tumor bed area was seen significantly more frequently in the IO-B patients (55.0 vs. 21.2 %). Skin thickening did not differ significantly. CONCLUSION: The IO-B led to significantly more fat necroses and local restricted parenchymal scarring in our analysis.
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Neoplasias de la Mama/patología , Carcinoma Ductal de Mama/patología , Carcinoma Lobular/patología , Electrones , Necrosis Grasa/patología , Mastectomía Segmentaria , Radioterapia Adyuvante , Adulto , Anciano , Anciano de 80 o más Años , Neoplasias de la Mama/terapia , Carcinoma Ductal de Mama/terapia , Carcinoma Lobular/terapia , Cicatriz , Terapia Combinada , Femenino , Estudios de Seguimiento , Humanos , Cuidados Intraoperatorios , Mamografía , Persona de Mediana Edad , Clasificación del Tumor , Estadificación de Neoplasias , Pronóstico , Dosificación Radioterapéutica , Estudios RetrospectivosRESUMEN
PURPOSE: To evaluate if computed tomography (CT) coronary calcium scoring is needed after detection of coronary calcifications on conventional chest radiographs. MATERIALS AND METHODS: One hundred and five patients (67 men; 57.2+/-12.8 years) with suspected coronary artery disease underwent conventional chest radiography and non-enhanced, retrospectively ECG-gated multislice spiral CT (MSCT) of the heart (4 mm x 2.5 mm, 120 kV, 133 mAs(eff.)). Chest radiographs were assessed independently by two radiologists. Detection of coronary calcifications was compared between both methods. Sensitivity, specificity, negative and positive predictive values, median, 25% and 75% percentiles for the detection of coronary calcifications were calculated. Receiver operating characteristics (ROC) analyses were computed. RESULTS: In 90 patients, MSCT revealed coronary calcifications. The mean coronary calcium score was 526.2 (0-4784.5). On chest radiographs, coronary calcifications were correctly detected in 46 (61) patients by observer 1 (observer 2). The corresponding sensitivity was 51.1% in observer 1 and 67.8% in observer 2. Median of detected coronary calcifications was 361.9 (426.4) for observer 1 (observer 2). Corresponding 25% und 75% percentiles were 109.6 (109.6) and 798.5 (898.5). The area under the ROC curve was 0.636 for observer 1 and 0.715 for observer 2. There was no correlation between image quality and the detection of coronary calcifications on plain film radiographs. CONCLUSION: As coronary calcifications of various extents are inconsistently detected on plain chest radiographs, CT calcium scoring may not be omitted even if coronary artery calcifications were detected on conventional chest radiographs.
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Calcinosis/diagnóstico por imagen , Angiografía Coronaria/métodos , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Radiografía Torácica/métodos , Tomografía Computarizada por Rayos X/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
The impact of image pattern recognition on accessing large databases of medical images has recently been explored, and content-based image retrieval (CBIR) in medical applications (IRMA) is researched. At the present, however, the impact of image retrieval on diagnosis is limited, and practical applications are scarce. One reason is the lack of suitable mechanisms for query refinement, in particular, the ability to (1) restore previous session states, (2) combine individual queries by Boolean operators, and (3) provide continuous-valued query refinement. This paper presents a powerful user interface for CBIR that provides all three mechanisms for extended query refinement. The various mechanisms of man-machine interaction during a retrieval session are grouped into four classes: (1) output modules, (2) parameter modules, (3) transaction modules, and (4) process modules, all of which are controlled by a detailed query logging. The query logging is linked to a relational database. Nested loops for interaction provide a maximum of flexibility within a minimum of complexity, as the entire data flow is still controlled within a single Web page. Our approach is implemented to support various modalities, orientations, and body regions using global features that model gray scale, texture, structure, and global shape characteristics. The resulting extended query refinement has a significant impact for medical CBIR applications.
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Almacenamiento y Recuperación de la Información/métodos , Internet/estadística & datos numéricos , Interpretación de Imagen Radiográfica Asistida por Computador , Sistemas de Información Radiológica/instrumentación , Interfaz Usuario-Computador , Gráficos por Computador , Bases de Datos Factuales , Diagnóstico por Imagen/métodos , Humanos , Aplicaciones de la Informática Médica , Reconocimiento de Normas Patrones Automatizadas , Sensibilidad y Especificidad , Diseño de SoftwareRESUMEN
Owing to the rapid development of scanner technology, thoracic computed tomography (CT) offers new possibilities but also faces enormous challenges with respect to the quality of computer-assisted diagnosis and therapy planning. In the framework of the Virtual Institute for Computer Assistance in Clinical Radiology cooperative research project, a software application was developed to assist the radiologist in the analysis of thoracic CT data for the purpose of evaluating the response to tumor therapy. The application provides follow-up support for monitoring of tumor therapy by means of volumetric quantification of tumors and temporal registration. In addition, anatomically adequate three-dimensional visualization techniques for convenient examination of large data sets are included. With close cooperation between computer scientists and radiologists, the application was tested and optimized to achieve a high degree of usability. Several clinical studies were carried out, the results of which indicated that the application improves therapy monitoring with respect to accuracy and time required.
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Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/secundario , Interpretación de Imagen Radiográfica Asistida por Computador , Tomografía Computarizada por Rayos X/métodos , Algoritmos , Humanos , Neoplasias Pulmonares/terapiaRESUMEN
Categorization of medical images means selecting the appropriate class for a given image out of a set of pre-defined categories. This is an important step for data mining and content-based image retrieval (CBIR). So far, published approaches are capable to distinguish up to 10 categories. In this paper, we evaluate automatic categorization into more than 80 categories describing the imaging modality and direction as well as the body part and biological system examined. Based on 6231 reference images from hospital routine, 85.5% correctness is obtained combining global texture features with scaled images. With a frequency of 97.7%, the correct class is within the best ten matches, which is sufficient for medical CBIR applications.
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Diagnóstico por Imagen , Almacenamiento y Recuperación de la Información , Automatización , AlemaniaRESUMEN
Automatic identification of frontal (posteroanterior/anteroposterior) vs. lateral chest radiographs is an important preprocessing step in computer-assisted diagnosis, content-based image retrieval, as well as picture archiving and communication systems. Here, a new approach is presented. After the radiographs are reduced substantially in size, several distance measures are applied for nearest-neighbor classification. Leaving-one-out experiments were performed based on 1,867 radiographs from clinical routine. For comparison to existing approaches, subsets of 430 and 5 training images are also considered. The overall best correctness of 99.7% is obtained for feature images of 32 x 32 pixels, the tangent distance, and a 5-nearest-neighbor classification scheme. Applying the normalized cross correlation function, correctness yields still 99.6% and 99.3% for feature images of 32 x 32 and 8 x 8 pixel, respectively. Remaining errors are caused by image altering pathologies, metal artifacts, or other interferences with routine conditions. The proposed algorithm outperforms existing but sophisticated approaches and is easily implemented at the same time.
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Interpretación de Imagen Radiográfica Asistida por Computador , Radiografía Torácica/métodos , Humanos , Modelos Estadísticos , Radiografía Torácica/normas , Programas InformáticosRESUMEN
RATIONALE AND OBJECTIVES: To compare low-dose multislice spiral CT (MSCT) with a standard protocol for the evaluation of acute lung injury (ALI) in an animal model. MATERIALS AND METHODS: Eleven healthy intubated pigs (weight: 32.4 kg +/- 1.9 kg) underwent lung lavage to induce experimental lung injury before CT examinations. Scanning was performed using a MSCT-technique. The entire chest was scanned using a thin-collimated protocol (140 kV; 100 mAs). The examinations were performed in inspiratory breath-hold in supine and in prone positions. Scanning was repeated after reduction of the tube current time product down to 20 mAs. All other parameters were kept constant. Subjective image quality was rated using a six-point scale by three experienced radiologists. In addition, objective criteria, based on signal to noise measurements, were assessed. Finally, the extent, localization, and distribution of lung opacities was analyzed using dedicated postprocessing software. RESULTS: Subjective image quality was rated inferior in the low-dose MSCT-examinations (prone position: 2.1 vs. 3.0; supine position: 1.5 vs. 2.5). Hence, pixel noise was nearly doubled. However, exact information about the extent, localization and distribution of lung opacities was provided. There were no statistically significant differences between standard and low-dose MSCT in this respect. CONCLUSIONS: In the animal experiments, low-dose MSCT-scanning did not impair the diagnostic accuracy in ALI, offering an advantageous reduction of radiation exposure.