104 research outputs found
Recommended from our members
3D printed ventricular septal defect patch: a primer for the 2015 Radiological Society of North America (RSNA) hands-on course in 3D printing.
Hand-held three dimensional models of the human anatomy and pathology, tailored-made protheses, and custom-designed implants can be derived from imaging modalities, most commonly Computed Tomography (CT). However, standard DICOM format images cannot be 3D printed; instead, additional image post-processing is required to transform the anatomy of interest into Standard Tessellation Language (STL) format is needed. This conversion, and the subsequent 3D printing of the STL file, requires a series of steps. Initial post-processing involves the segmentation-demarcation of the desired for 3D printing parts and creating of an initial STL file. Then, Computer Aided Design (CAD) software is used, particularly for wrapping, smoothing and trimming. Devices and implants that can also be 3D printed, can be designed using this software environment. The purpose of this article is to provide a tutorial on 3D Printing with the test case of complex congenital heart disease (CHD). While the infant was born with double outlet right ventricle (DORV), this hands-on guide to be featured at the 2015 annual meeting of the Radiological Society of North America Hands-on Course in 3D Printing focused on the additional finding of a ventricular septal defect (VSD). The process of segmenting the heart chambers and the great vessels will be followed by optimization of the model using CAD software. A virtual patch that accurately matches the patient's VSD will be designed and both models will be prepared for 3D printing
Clinical situations for which 3D printing is considered an appropriate representation or extension of data contained in a medical imaging examination: Neurosurgical and otolaryngologic conditions
BACKGROUND: Medical three dimensional (3D) printing is performed for neurosurgical and otolaryngologic conditions, but without evidence-based guidance on clinical appropriateness. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (SIG) provides appropriateness recommendations for neurologic 3D printing conditions.
METHODS: A structured literature search was conducted to identify all relevant articles using 3D printing technology associated with neurologic and otolaryngologic conditions. Each study was vetted by the authors and strength of evidence was assessed according to published guidelines.
RESULTS: Evidence-based recommendations for when 3D printing is appropriate are provided for diseases of the calvaria and skull base, brain tumors and cerebrovascular disease. Recommendations are provided in accordance with strength of evidence of publications corresponding to each neurologic condition combined with expert opinion from members of the 3D printing SIG.
CONCLUSIONS: This consensus guidance document, created by the members of the 3D printing SIG, provides a reference for clinical standards of 3D printing for neurologic conditions
Clinical situations for which 3D Printing is considered an appropriate representation or extension of data contained in a medical imaging examination: Vascular conditions
BACKGROUND: Medical three-dimensional (3D) printing has demonstrated utility and value in anatomic models for vascular conditions. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (3DPSIG) provides appropriateness recommendations for vascular 3D printing indications.
METHODS: A structured literature search was conducted to identify all relevant articles using 3D printing technology associated with vascular indications. Each study was vetted by the authors and strength of evidence was assessed according to published appropriateness ratings.
RESULTS: Evidence-based recommendations for when 3D printing is appropriate are provided for the following areas: aneurysm, dissection, extremity vascular disease, other arterial diseases, acute venous thromboembolic disease, venous disorders, lymphedema, congenital vascular malformations, vascular trauma, vascular tumors, visceral vasculature for surgical planning, dialysis access, vascular research/development and modeling, and other vasculopathy. Recommendations are provided in accordance with strength of evidence of publications corresponding to each vascular condition combined with expert opinion from members of the 3DPSIG.
CONCLUSION: This consensus appropriateness ratings document, created by the members of the 3DPSIG, provides an updated reference for clinical standards of 3D printing for the care of patients with vascular conditions
Noninvasive Vascular Images for Face Transplant Surgical Planning
Objective: Face transplantation replaces substantial defects with anatomically identical donor tissues; preoperative vascular assessment relies on noninvasive imaging to separate and characterize the external carotid vessels and branches. The objective is to describe and illustrate vascular considerations for face transplantation candidates. Methods: Novel noninvasive imaging using computed tomography and magnetic resonance imaging over 3 spatial dimensions plus time was developed and tested in 4 face transplant candidates. Precontrast images assessed bones and underlying metal. Contrast media was used to delineate and separate arteries from veins. For computed tomography, acquisition over multiple time points enabled the computation of tissue perfusion metrics. Time-resolved magnetic resonance angiography was performed to separate arterial and venous phases. Results: The range of circulation times for the external carotid system was 6 to 14 seconds from arterial blush to loss of venous enhancement. Precontrast imaging provided a roadmap of bones and metal. Among the 4 patients, 3 had surgical clips, metal implants, or both within 1 cm of major vessels considered for surgery. Contrast-enhanced wide area detector computed tomographic data acquired in the axial mode separated these structures and provided arterial and venous images for planning the surgical anastomoses. Magnetic resonance imaging was able to distinguish between the large vessels from the external carotid systems. Conclusions: Vascular imaging maps are challenging in face transplantation because of the rapid circulation times and artifact from the initial injury, prior reconstructive attempts, or both. Nevertheless, face transplant candidates require high spatial and temporal resolution vascular imaging to determine those vessels appropriate for surgical anastomoses
Whole heart self-navigated 3D radial MRI for the creation of virtual 3D models in congenital heart disease
Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): guidelines for medical 3D printing and appropriateness for clinical scenarios
Abstract
Medical three-dimensional (3D) printing has expanded dramatically over the past three decades with growth in both facility adoption and the variety of medical applications. Consideration for each step required to create accurate 3D printed models from medical imaging data impacts patient care and management. In this paper, a writing group representing the Radiological Society of North America Special Interest Group on 3D Printing (SIG) provides recommendations that have been vetted and voted on by the SIG active membership. This body of work includes appropriate clinical use of anatomic models 3D printed for diagnostic use in the care of patients with specific medical conditions. The recommendations provide guidance for approaches and tools in medical 3D printing, from image acquisition, segmentation of the desired anatomy intended for 3D printing, creation of a 3D-printable model, and post-processing of 3D printed anatomic models for patient care.https://deepblue.lib.umich.edu/bitstream/2027.42/146524/1/41205_2018_Article_30.pd
Evolution of the Color-Magnitude Relation in Galaxy Clusters at z ~1 from the ACS Intermediate Redshift Cluster Survey
We apply detailed observations of the Color-Magnitude Relation (CMR) with the
ACS/HST to study galaxy evolution in eight clusters at z~1. The early-type red
sequence is well defined and elliptical and lenticular galaxies lie on similar
CMRs. We analyze CMR parameters as a function of redshift, galaxy properties
and cluster mass. For bright galaxies (M_B < -21mag), the CMR scatter of the
elliptical population in cluster cores is smaller than that of the S0
population, although the two become similar at faint magnitudes. While the
bright S0 population consistently shows larger scatter than the ellipticals,
the scatter of the latter increases in the peripheral cluster regions. If we
interpret these results as due to age differences, bright elliptical galaxies
in cluster cores are on average older than S0 galaxies and peripheral
elliptical galaxies (by about 0.5Gyr). CMR zero point, slope, and scatter in
the (U-B)_z=0 rest-frame show no significant evolution out to redshift z~1.3
nor significant dependence on cluster mass. Two of our clusters display CMR
zero points that are redder (by ~2sigma) than the average (U-B)_z=0 of our
sample. We also analyze the fraction of morphological early-type and late-type
galaxies on the red sequence. We find that, while in the majority of the
clusters most (80% to 90%) of the CMR population is composed of early-type
galaxies, in the highest redshift, low mass cluster of our sample, the CMR
late-type/early-type fractions are similar (~50%), with most of the late-type
population composed of galaxies classified as S0/a. This trend is not
correlated with the cluster's X-ray luminosity, nor with its velocity
dispersion, and could be a real evolution with redshift.Comment: ApJ, in press, 27 pages, 22 figure
The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III
The Sloan Digital Sky Survey (SDSS) started a new phase in August 2008, with
new instrumentation and new surveys focused on Galactic structure and chemical
evolution, measurements of the baryon oscillation feature in the clustering of
galaxies and the quasar Ly alpha forest, and a radial velocity search for
planets around ~8000 stars. This paper describes the first data release of
SDSS-III (and the eighth counting from the beginning of the SDSS). The release
includes five-band imaging of roughly 5200 deg^2 in the Southern Galactic Cap,
bringing the total footprint of the SDSS imaging to 14,555 deg^2, or over a
third of the Celestial Sphere. All the imaging data have been reprocessed with
an improved sky-subtraction algorithm and a final, self-consistent photometric
recalibration and flat-field determination. This release also includes all data
from the second phase of the Sloan Extension for Galactic Understanding and
Evolution (SEGUE-2), consisting of spectroscopy of approximately 118,000 stars
at both high and low Galactic latitudes. All the more than half a million
stellar spectra obtained with the SDSS spectrograph have been reprocessed
through an improved stellar parameters pipeline, which has better determination
of metallicity for high metallicity stars.Comment: Astrophysical Journal Supplements, in press (minor updates from
submitted version
The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey
The Sloan Digital Sky Survey III (SDSS-III) presents the first spectroscopic
data from the Baryon Oscillation Spectroscopic Survey (BOSS). This ninth data
release (DR9) of the SDSS project includes 535,995 new galaxy spectra (median
z=0.52), 102,100 new quasar spectra (median z=2.32), and 90,897 new stellar
spectra, along with the data presented in previous data releases. These spectra
were obtained with the new BOSS spectrograph and were taken between 2009
December and 2011 July. In addition, the stellar parameters pipeline, which
determines radial velocities, surface temperatures, surface gravities, and
metallicities of stars, has been updated and refined with improvements in
temperature estimates for stars with T_eff<5000 K and in metallicity estimates
for stars with [Fe/H]>-0.5. DR9 includes new stellar parameters for all stars
presented in DR8, including stars from SDSS-I and II, as well as those observed
as part of the SDSS-III Sloan Extension for Galactic Understanding and
Exploration-2 (SEGUE-2).
The astrometry error introduced in the DR8 imaging catalogs has been
corrected in the DR9 data products. The next data release for SDSS-III will be
in Summer 2013, which will present the first data from the Apache Point
Observatory Galactic Evolution Experiment (APOGEE) along with another year of
data from BOSS, followed by the final SDSS-III data release in December 2014.Comment: 9 figures; 2 tables. Submitted to ApJS. DR9 is available at
http://www.sdss3.org/dr
- …