Alzheimer's disease (AD) and frontal lobe dementia (FLD) show characteristic patterns of regional cerebral blood flow (rCBF). However, these patterns may overlap with those observed in the aging ...brain in elderly normal individuals. The aim of this study was to develop a new method for better classification and recognition of AD and FLD cases as compared with normal controls. Forty-six patients with AD, 7 patients with FLD and 34 normal controls (CTR) were included in the study. rCBF was assessed by technetium-99m hexamethylpropylene amine oxime and a three-headed single-photon emission tomography (SPET) camera. A brain atlas was used to define volumes of interest (VOIs) corresponding to the brain lobes. In addition to conventional image processing methods, based on count density/voxel, the new approach also analysed other intrinsic properties of the data by means of gradient computation steps. Hereby, five factors were assessed and tested separately: the mean count density/voxel and its histogram, the mean gradient and its histogram, and the gradient angle co-occurrence matrix. A feature vector concatenating single features was also created and tested. Preliminary feature discrimination was performed using a two-sided t-test and a K-means clustering was then used to classify the image sets into categories. Finally, five-dimensional co-occurrence matrices combining the different intrinsic properties were computed for each VOI, and their ability to recognise the group to which each individual scan belonged was investigated. For correct classification of the AD-CTR groups, the gradient histogram in the parieto-temporal lobes was the most useful single feature (accuracy 91%). FLD and CTR were better classified by the count density/voxel histogram (frontal and occipital lobes) and by the mean gradient (frontal, temporal and parietal lobes, accuracy 98%). For AD and FLD the count density/voxel histogram in the frontal, parietal and occipital lobes classified the groups with the highest accuracy (85%). The concatenated joint feature correctly classified 96% of the AD-CTR, 98% of the FLD-CTR and 94% of the AD-FLD cases. 5D co-occurrence matrices correctly recognised 98% of the AD-CTR cases, 100% of the FLD-CTR cases and 98% of the AD-FLD cases. The proposed approach classified and diagnosed AD and FLD patients with higher accuracy than conventional analytical methods used for rCBF-SPET. This was achieved by extracting from the SPET data the intrinsic information content in each of the selected VOIs.
Relevance and diagnostics of cryoproteins Nebe, Carl Thomas; Stamminger, Gudrun; Baum, Hannsjörg ...
Laboratoriumsmedizin,
6/2015, Letnik:
38, Številka:
5
Journal Article
Odprti dostop
Cryoproteins still remain largely undiagnosed despite their clinical relevance. Cryoglobulins, cryofibrinogen and cold agglutinins respectively show a significant association with autoimmune diseases ...and non-Hodgkin’s lymphoma. The analytical part is relatively straightforward; however, the preanalytical phase is a challenge. This article briefly summarizes the relevant aspects to improve this situation.
Osteomyelitis of the ischiopubic synchondrosis in children is not rare and presents a diagnostic problem because of the diversity of presentation and the deceptive nature of symptoms. Radiological ...assessment is extremely difficult because of the variation in normal ossification on radiography and normal physiological uptake on radioisotope bone scan. We present two cases of osteomyelitis of the ischiopubic synchondrosis and describe findings on radiographs, isotope bone scan, computed tomography (CT) and magnetic resonance imaging (MRI). MRI changes have not been described in any of the case reports in the English literature. Aspiration and biopsy remain the gold standard for diagnosis. However, MRI appearances can significantly increase diagnostic confidence prior to intervention.
Clinical descriptions, diagnostic guidelines and codes for mental and behavioural disorders encountered in clinical psychiatry. The book has been developed from chapter V of the 10th revision of "The ...International Statistical Classification of Diseases and Related Health Problems (ICD-10).
Zusammenfassung
Hintergrund
Bei klinischem Frakturverdacht gilt die konventionelle Röntgendiagnostik als Standard, deren Einsatz jedoch streng indiziert sein sollte. Die Sonographie bietet eine ...sichere und strahlenfreie Alternative zur Frakturdiagnostik.
Fragestellung
Sensitivität und Spezifität der Fraktursonographie und Sicherheit sonographischer Algorithmen in der Frakturdiagnostik.
Methode
Darstellung typischer Einsatzgebiete der Fraktursonographie und Etablierung sonographischer Standards zur sicheren Frakturdiagnostik.
Ergebnisse
Distale Unterarmfrakturen lassen sich allein sonographisch diagnostizieren (Sensitivität 96 %, Spezifität 97 %). Bei Ellenbogenverletzungen ist das sonographische Fettkörperzeichen („sonographic fat pad“, SOFA) nützlich in der Primärevaluation. Ein positives Fettkörperzeichen (SOFA+) weist auf eine Fraktur hin und eine Röntgendiagnostik ist indiziert (Sensitivität 97 %, Spezifität 91 %). Bei subkapitalen Humerusfrakturen liegt der sonographische Nutzen im Frakturausschluss (Sensitivität 94 %, Spezifität 100 %) und in der Achsbestimmung bei vorliegender Fraktur.
Schlussfolgerung
Sonographische Algorithmen zur Frakturevaluation (SAFE) ermöglichen bei bestimmten kindlichen Frakturen eine sichere Diagnostik und Therapiesteuerung und verringern so eine unnötige Röntgenstrahlenbelastung.
The use of clinical and laboratory information to detect conditions and predict patient outcomes is a mainstay of medical practice. Modern biotechnology offers increasing potential to develop ...sophisticated tests for these purposes. This book describes the statistical concepts and techniques for evaluating the accuracy of medical tests. Worked examples include applications to cancer biomarker studies, prospective disease screening studies, diagnostic radiology studies and audiology testing studies. The statistical methodology can be broadly applied for evaluating classifiers and to problems beyond medical settings. Several measures for quantifying test accuracy are described including the Receiver Operating Characteristic Curve. Pepe presents statistical procedures for the estimation and comparison of those measures among tests. Regression frameworks for assessing factors that influence test accuracy and for comparing tests while adjusting for such factors are presented. The sequence of research steps involved in the development of a test is considered in some detail. Sample size calculations and other issues pertinent to study design are described for tests at various phases of development. In addition, the impacts of missing data and imperfect reference data are addressed. These problems often occur in practice, and modern statistical procedures for dealing with them are discussed. Additional topics that are covered include: meta-analysis for summarizing the results of multiple studies of a test; the evaluation of markers for predicting event time data; and procedures for combining the results of multiple tests to improve classification. This book should be of interest to quantitative researchers and practicing statisticians. The book also covers the theoretical foundations for statistical inference and should therefore be of interest to academic statisticians including those involved in statistical methodological research in this field.
The non-invasive assessment of postoperative spinal infections can pose a substantial diagnostic challenge, especially in the presence of orthopaedic devices. Whereas white blood cell scanning is of ...limited use in the spine, the low normal bone marrow uptake of technetium-99m ciprofloxacin combined with its claimed bacterial specificity makes it theoretically an ideal candidate for the evaluation of postoperative spinal infections. This study aimed to evaluate 99mTc-ciprofloxacin planar and single-photon emission tomography (SPET) imaging in relation to microbiological and clinical diagnosis in the postoperative spine. Planar imaging was performed at 1, 3 and 24 h and SPET was performed at 3 h post injection of 370 MBq 99mTc-ciprofloxacin. Images were scored by two independent certified nuclear medicine physicians, blinded to the final diagnosis. Within the 48 patients, there were 13 deep infections. Sensitivity, specificity and accuracy at visual scoring were respectively 54%, 71% and 67% (1 h), 62%, 77% and 73% (3 h), 42%, 91% and 77% (24 h) for planar imaging and 100%, 74% and 81% for SPET. When recently operated patients (< 6 months) were excluded, the specificity of the SPET imaging rose to 81%. In conclusion, unlike white blood cell scanning, 99mTc-ciprofloxacin SPET is sensitive in evaluating infections in the postoperative spine. Sensitivity is much higher for SPET than for planar imaging. However, the results presented prove that its specificity is limited, especially in recently operated patients. Taking this limitation into account, we advise planar and SPET imaging at 3 h post injection and an interval of at least 6 months after surgery to minimise the likelihood of false positives.
Zusammenfassung
Hintergrund
Mit den technischen Weiterentwicklungen in den vergangenen Jahren hat sich die MRT zu einem methodisch ausgereiften und für spezifische pulmonale Fragestellungen bereits ...auch klinisch bewährten Untersuchungsverfahren entwickelt. Ohne Strahlenexposition kombiniert sie morphologische und funktionelle Diagnostik und ergänzt das Spektrum der etablierten Verfahren für die bildgebende Diagnostik der Lunge.
Ziel der Arbeit und Methoden
Diese Arbeit gibt einen Überblick über die aktuell verwendeten Sequenzen und Techniken zur Darstellung pulmonaler Rundherde und analysiert deren klinischen Stellenwert anhand der aktuellen Studienlage. In Zentrum stehen dabei die Detektion pulmonaler Metastasen, die Detektion primär pulmonaler Malignome bei Personen mit Risikoprofil und die Abklärung pulmonaler Rundherde hinsichtlich ihrer Dignität.
Ergebnisse und Diskussion
Die MRT besitzt im Vergleich zum Referenzstandard Niedrigdosis-CT eine Sensitivität von ca. 80 % für die Detektion maligner pulmonaler Rundherde und ist der CT damit etwas unterlegen. Vorteile der MRT gegenüber der Niedrigdosis-CT sind andererseits die höhere Spezifität bei der Differenzierung maligner und benigner pulmonaler Rundherde sowie die fehlende Strahlenexposition. Außerhalb von Studien kann ein breiter Einsatz der MRT als Screeningverfahren zur Detektion und Abklärung pulmonaler Rundherde aufgrund der noch ungenügenden Datenlage derzeit noch nicht empfohlen werden. Das diagnostische Potenzial der MRT für die Früherkennung und das Staging pulmonaler Malignome rechtfertigt aber die weitere Evaluation der MRT als sekundäre Modalität im Rahmen von Studien.
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