Matthias Benndorf

Comparison of Multidetector Computed Tomography and Flat-Panel Computed Tomography Regarding Visualization of Cortical Fractures, Cortical Defects, and Orthopedic Screws: A Phantom Study.

Abstract To compare the visualization of cortical fractures, cortical defects, and orthopedic screws in a dedicated extremity flat-panel computed tomography (FPCT) scanner and a multidetector computed tomography (MDCT) scanner. We used feet of European roe deer as phantoms for cortical fractures, cortical defects, and implanted orthopedic screws. FPCT and MDCT scans were performed with equivalent dose settings. Six observers rated the scans according to number of fragments, size of defects, size of defects opposite orthopedic screws, and the length of different screws. The image quality regarding depiction of the cortical bone was assessed. The gold standard (real number of fragments) was evaluated by autopsy. The correlation of reader assessment of fragments, cortical defects, and screws with the gold standard was similar for FPCT and MDCT. Three readers rated the subjective image quality of the MDCT to be higher, whereas the others showed no preferences. Although the image quality was rated higher in the MDCT than in the FPCT by 3 out of 6 observers, both modalities proved to be comparable regarding the visualization of cortical fractures, cortical defects, and orthopedic screws and of use to musculoskeletal radiology regarding fracture detection and postsurgical evaluation in our experimental setting.

Provision of the DDSM mammography metadata in an accessible format.

PURPOSE The Digital Database for Screening Mammography (DDSM) is the largest publicly available resource for mammographic image analysis research and has been used extensively in the past for computer assisted diagnosis (CADx) studies. However, the database has not been searchable for a specific kind of lesion, which rendered the case selection process in past studies often times arbitrary. Therefore, the authors want to provide the complete metadata of the DDSM in an accessible format. METHODS The authors semiautomatically transformed the data available athttp://marathon.csee.usf.edu/Mammography/Database.html into table format. The 1769 cases (914 from cancer volumes, 855 from benign volumes) comprise 1220 mass lesions (578 benign, 642 malignant) and 859 calcifications (433 benign, 426 malignant). Additionally, 694 normal cases were processed to allow for matching according to age and breast density. RESULTS The authors provide the entire DDSM metadata (for benign, malignant, and normal cases) as tab-delimited text files[see supplementary material at http://dx.doi.org/10.1118/1.4870379E-MPHYA6-41-006405 for DDSM metadata]. CONCLUSIONS The data provided make the case selection for future studies using the DDSM reproducible. Furthermore, it may serve as a validation dataset for CADx approaches using the BI-RADS lexicon.

Validating automated kidney stone volumetry in computed tomography and mathematical correlation with estimated stone volume based on diameter

Abstract Objectives: To validate AutoMated UroLithiasis Evaluation Tool (AMULET) software for kidney stone volumetry and compare its performance to standard clinical practice. Materials and Methods: Maximum diameter and volume of 96 urinary stones were measured as reference standard by three independent urologists. The same stones were positioned in an anthropomorphic phantom and CT scans acquired in standard settings. Three independent radiologists blinded to the reference values took manual measurements of the maximum diameter and automatic measurements of maximum diameter and volume. An “expected volume” was calculated based on manual diameter measurements using the formula: \documentclass{aastex}\usepackage{amsbsy}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{bm}\usepackage{mathrsfs}\usepackage{pifont}\usepackage{stmaryrd}\usepackage{textcomp}\usepackage{portland, xspace}\usepackage{amsmath, amsxtra}\usepackage{upgreek}\pagestyle{empty}\DeclareMathSizes{10}{9}{7}{6}\begin{document}

Trennung von Perfusion und Diffusion in Herdbefunden der Leber – klinische Anwendung zur Differenzierung metastasensuspekter Befunde.

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Assessing the degree of collinearity among the lesion features of the MRI BI-RADS lexicon.

OBJECTIVES To estimate diagnostic accuracy and interobserver agreement of extremity-dedicated low-field magnetic resonance imaging (lfMRI) for meniscal tears, anterior cruciate ligament (ACL) tears and knee fractures. METHODS We enrolled 62 patients with acute knee trauma and 19 patients with suspected knee fracture. Arthroscopy/Computed tomography was regarded the gold standard for cruciate ligament and meniscal tears/fractures. RESULTS Arthroscopy showed 39 meniscal tears. Sensitivity/Specificity of lfMRI was 95.8%/97.4% (reader 1)/100%/100% (reader 2) for medial and 93.3%/100% (reader 1)/93.3%/93.6% (reader 2) for lateral meniscal tears. Sensitivity/Specificity was 100% for ACL tears and fractures. Interobserver agreement was very good. CONCLUSION lfMRI showed reproducible high sensitivity and specificity for the diagnosis of the acutely injured knee.

Bayesian pretest probability estimation for primary malignant bone tumors based on the Surveillance, Epidemiology and End Results Program (SEER) database

Ziele: Die DWI ermoglicht die quantitative Abschatzung von Gewebecharakteristika. Zu den messbaren Signalveranderungen tragt nach der IVIM Theorie (le Bihan 1988) neben der extrazellularen Bewegung von Wassermolekulen auch die kapillare Perfusion bei. Es lassen sich so Perfusion und Diffusion nichtinvasiv differenzieren. Wir untersuchten die klinische Anwendung dieser Methode zur Differenzierung metastasensuspekter Leberbefunde. Methode: Eingeschlossen wurden Patienten, welche in einem Zeitraum von 12 Monaten mit der Fragestellung Metastasen zu einer MRT der Leber uberwiesen wurden. Patienten unter Chemotherapie wurden ausgeschlossen. Das Protokoll schlos eine DWI Sequenz (EPI, fatsat, TR/TE 2000/65ms, freie Atmung, 12 Mittelungen, 5 b-Werte (0, 100, 300, 600, 1000s/mm^2)) ein. Signalintensitaten der DWI bei entsprechenden b-Werten wurden durch zwei Radiologen im Konsensus gemessen. Die Messwerte wurden einer biexponentiellen (y=(1-f)*e^(-b*D)+f*e^(-b*D*)) nichtlinearen Regression zugefuhrt. Die Modellparameter f (Perfusionsfraktion), D (Diffusivitat) und D*(Pseudodifussionskoeffizient) wurden einer univariaten ROC und multivariaten logistischen Regressionsanalyse zugefuhrt. Referenzstandard bildeten Histologie oder Verlaufskontrolle >12 Monate. Ergebnis: 41 eingeschlossene Patienten (mittleres Alter 58J) zeigten 95 Herdbefunde (61 maligne, 34 benigne). Gemas univariater ROC Analyse zeigte D die hochste Genauigkeit zur Differenzierung von benignen und malignen Herdbefunden (ROC 0,706, P<0,05). Die Kombination von f und D zeigte die hochste ROC (0,851, P<0,05). Schlussfolgerung: Die Perfusion und Diffusion berucksichtigende Abschatzung nichtkoharenter Bewegung unter Verwendung eines Mehrkompartmentmodells unter klinischen Bedingungen ergab eine hohe diagnostische Genauigkeit zur Differenzierung zwischen metastasenverdachtigen Befunden. Keywords: Leber, DWI, IVIM, Primovist, Metastasen Korrespondierender Autor: Baltzer PA Universitatsklinikum Jena, IDIR, Erlanger Allee 101, 07740 Jena E-Mail: pascal.baltzer@med.uni-jena.de