55 research outputs found
ISKOPAVANJA U ASERIJI
Zbog iznimne važnosti teksta za izučavanje Aserije, koji je tiskan 1908. godine, uredništvo časopisa se odlučilo na objavu prevoda. Izvornik: H. LIEBL, W. WILBERG, Ausgrabungen in Asseria, Jahreshefte des Österreichischen Archäologischen Instituts, 11, Wien, 1908., 17-88
Bone Mineral Density Estimations From Routine Multidetector Computed Tomography: A Comparative Study of Contrast and Calibration Effects.
INTRODUCTION
Phantom-based (synchronous and asynchronous) and phantomless (internal tissue calibration based) assessment of bone mineral density (BMD) in routine MDCT (multidetector computed tomography) examinations potentially allows for diagnosis of osteoporosis. Although recent studies investigated the effects of contrast-medium application on phantom-calibrated BMD measurements, it remains uncertain to what extent internal tissue-calibrated BMD measurements are also susceptible to contrast-medium associated density variation. The present study is the first to systemically evaluate BMD variations related to contrast application comparing different calibration techniques.
PURPOSE
To compare predicative performance of different calibration techniques for BMD measurements obtained from triphasic contrast-enhanced MDCT.
MATERIALS AND METHODS
Bone mineral density was measured on nonenhanced (NE), arterial (AR) and portal-venous (PV) contrast phase MDCT images of 46 patients using synchronous (SYNC) and asynchronous (ASYNC) phantom calibration as well as internal calibration (IC). Quantitative computed tomography (QCT) served as criterion standard. Density variations were analyzed for each contrast phase and calibration technique, and respective linear fitting was performed.
RESULTS
Both asynchronous calibration-derived BMD values (NE-ASYNC) and values estimated using IC (NE-IC) on NE MDCT images did reasonably well in predicting QCT BMD (root-mean-square deviation, 8.0% and 7.8%, respectively). Average NE-IC BMD was 2.7% lower when compared with QCT (P = 0.017), whereas no difference could be found for NE-ASYNC (P = 0.957). All average BMD estimates derived from contrast-enhanced scans differed significantly from QCT BMD (all P 6.0 mg/mL). All regression fits revealed a consistent linear dependency (R range, 0.861-0.963). Overall accuracy and goodness of fit tended to decrease from AR to PV contrast phase. Highest precision and best linear fit could be reached using a synchronously scanned phantom (root-mean-square deviation, 9.4% for AR and 14.4% for PV). Both ASYNC and IC estimations performed comparably accurate and precise.
CONCLUSIONS
Our data suggest that internal calibration driven BMD measurements derived from contrast-enhanced MDCT need the same amount of post hoc contrast-effect adjustment as measurements using phantom calibration. Adjustment using linear correction equations can correct for systematic bias of bone density variations related to contrast application, irrespective of the calibration technique used
MedShapeNet -- A Large-Scale Dataset of 3D Medical Shapes for Computer Vision
Prior to the deep learning era, shape was commonly used to describe the
objects. Nowadays, state-of-the-art (SOTA) algorithms in medical imaging are
predominantly diverging from computer vision, where voxel grids, meshes, point
clouds, and implicit surface models are used. This is seen from numerous
shape-related publications in premier vision conferences as well as the growing
popularity of ShapeNet (about 51,300 models) and Princeton ModelNet (127,915
models). For the medical domain, we present a large collection of anatomical
shapes (e.g., bones, organs, vessels) and 3D models of surgical instrument,
called MedShapeNet, created to facilitate the translation of data-driven vision
algorithms to medical applications and to adapt SOTA vision algorithms to
medical problems. As a unique feature, we directly model the majority of shapes
on the imaging data of real patients. As of today, MedShapeNet includes 23
dataset with more than 100,000 shapes that are paired with annotations (ground
truth). Our data is freely accessible via a web interface and a Python
application programming interface (API) and can be used for discriminative,
reconstructive, and variational benchmarks as well as various applications in
virtual, augmented, or mixed reality, and 3D printing. Exemplary, we present
use cases in the fields of classification of brain tumors, facial and skull
reconstructions, multi-class anatomy completion, education, and 3D printing. In
future, we will extend the data and improve the interfaces. The project pages
are: https://medshapenet.ikim.nrw/ and
https://github.com/Jianningli/medshapenet-feedbackComment: 16 page
Die Disticha Cornuti, auch Cornutus oder Distigium des Jo. v. Carlaudia genannt, und der Scholiast Cornutus : mit dem Text des Cornutus antiquus und novus
vom Kgl. Studienlehrer Hans Lieb
Beiträge zu den Persius-Scholien
vom Kgl. Studienlehrer Hans Lieb
ISKOPAVANJA U ASERIJI
Zbog iznimne važnosti teksta za izučavanje Aserije, koji je tiskan 1908. godine, uredništvo časopisa se odlučilo na objavu prevoda. Izvornik: H. LIEBL, W. WILBERG, Ausgrabungen in Asseria, Jahreshefte des Österreichischen Archäologischen Instituts, 11, Wien, 1908., 17-88
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