Evaluation of an AI program in thoracic imaging: Performance in detection of thoracic aorta ectasia

2021 ◽  
Author(s):  
Francisco João Miranda Antunes
Keyword(s):  
Thoracic Aorta ◽  
Thoracic Imaging ◽  
Imaging Performance

The influence of confocal microscope design on imaging performance

1993 ◽  
Vol 51 ◽  
pp. 144-145
Author(s):  
C J R Sheppard
Keyword(s):  
Image Quality ◽  
Fluorescence Imaging ◽  
Confocal Microscope ◽  
Industrial Applications ◽  
Three Dimensions ◽  
Design Parameters ◽  
Weak Signals ◽  
Size And Shape ◽  
Imaging Performance ◽  
Fundamental Limitation

The confocal microscope is now widely used in both biomedical and industrial applications for imaging, in three dimensions, objects with appreciable depth. There are now a range of different microscopes on the market, which have adopted a variety of different designs. The aim of this paper is to explore the effects on imaging performance of design parameters including the method of scanning, the type of detector, and the size and shape of the confocal aperture.It is becoming apparent that there is no such thing as an ideal confocal microscope: all systems have limitations and the best compromise depends on what the microscope is used for and how it is used. The most important compromise at present is between image quality and speed of scanning, which is particularly apparent when imaging with very weak signals. If great speed is not of importance, then the fundamental limitation for fluorescence imaging is the detection of sufficient numbers of photons before the fluorochrome bleaches.

A new method for the observation of Type II magnetic contrast

1990 ◽  
Vol 48 (4) ◽  
pp. 764-765
Author(s):  
R.P. Ferrier ◽  
S. McVitie
Keyword(s):  
Domain Walls ◽  
Incident Beam ◽  
Objective Lens ◽  
Type Ii ◽  
Backscattering Coefficient ◽  
Magnetic Contrast ◽  
Standard Geometry ◽  
Backscattered Electron ◽  
Imaging Performance ◽  
Good Probe

Type II magnetic contrast was first observed by Philibert and Tixier and relies on the change in the effective backscattering coefficient due to interaction of the scattered electrons within the specimen and the local magnetic induction (for a review see Tsuno). Depending on the tilt of the specimen and the position of the backscattered electron detector(s), contrast due to the presence of either or both domains and domain walls can be obtained; in the case of the latter, the standard geometry is for the specimen to be normal to the incident beam and the detectors are positioned above it and close to the optic axis. This is the geometry adopted in our studies, which used a JEOL 2000FX with a special split objective lens polepiece; this permitted the specimen to be in magnetic field-free space, the separate lens gaps above and below allowing good probe forming capabilities combined with excellent Lorentz imaging performance. A schematic diagram is shown in Fig. 1.

New Feasible Concepts of Aberration Correction for Realizing High-Resolution Electron Microscopes

1990 ◽  
Vol 48 (1) ◽  
pp. 202-203
Author(s):  
H. Rose
Keyword(s):  
Spherical Aberration ◽  
Wave Length ◽  
Electron Wave ◽  
Optical Lens ◽  
Resolution Electron ◽  
Rotationally Symmetric ◽  
Electron Microscopes ◽  
The Cost ◽  
Imaging Performance ◽  
Acceleration Voltage

The imaging performance of the light optical lens systems has reached such a degree of perfection that nowadays numerical apertures of about 1 can be utilized. Compared to this state of development the objective lenses of electron microscopes are rather poor allowing at most usable apertures somewhat smaller than 10-2 . This severe shortcoming is due to the unavoidable axial chromatic and spherical aberration of rotationally symmetric electron lenses employed so far in all electron microscopes.The resolution of such electron microscopes can only be improved by increasing the accelerating voltage which shortens the electron wave length. Unfortunately, this procedure is rather ineffective because the achievable gain in resolution is only proportional to λ1/4 for a fixed magnetic field strength determined by the magnetic saturation of the pole pieces. Moreover, increasing the acceleration voltage results in deleterious knock-on processes and in extreme difficulties to stabilize the high voltage. Last not least the cost increase exponentially with voltage.

Dilatation of the entire thoracic aorta in patients with bicuspid aortic valve: a magnetic resonance angiography study

VASA ◽  
2005 ◽  
Vol 34 (3) ◽  
pp. 181-185 ◽  
Author(s):  
Westhoff-Bleck ◽  
Meyer ◽  
Lotz ◽  
Tutarel ◽  
Weiss ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Angiography ◽  
Aortic Valve ◽  
Pulmonary Artery ◽  
Aortic Arch ◽  
Thoracic Aorta ◽  
Aortic Root ◽  
Ascending Aorta ◽  
Descending Aorta ◽  
Severe Aortic Regurgitation

Background: The presence of a bicuspid aortic valve (BAV) might be associated with a progressive dilatation of the aortic root and ascending aorta. However, involvement of the aortic arch and descending aorta has not yet been elucidated. Patients and methods: Magnetic resonance angiography (MRA) was used to assess the diameter of the ascending aorta, aortic arch, and descending aorta in 28 patients with bicuspid aortic valves (mean age 30 ± 9 years). Results: Patients with BAV, but without significant aortic stenosis or regurgitation (n = 10, mean age 27 ± 8 years, n.s. versus control) were compared with controls (n = 13, mean age 33 ± 10 years). In the BAV-patients, aortic root diameter was 35.1 ± 4.9 mm versus 28.9 ± 4.8 mm in the control group (p < 0.01). The diameter of the ascending aorta was also significantly increased at the level of the pulmonary artery (35.5 ± 5.6 mm versus 27.0 ± 4.8 mm, p < 0.001). BAV-patients with moderate or severe aortic regurgitation (n = 18, mean age 32 ± 9 years, n.s. versus control) had a significant dilatation of the aortic root, ascending aorta at the level of the pulmonary artery (41.7 ± 4.8 mm versus 27.0 ± 4.8 mm in control patients, p < 0.001) and, furthermore, significantly increased diameters of the aortic arch (27.1 ± 5.6 mm versus 21.5 ± 1.8 mm, p < 0.01) and descending aorta (21.8 ± 5.6 mm versus 17.0 ± 5.6 mm, p < 0.01). Conclusions: The whole thoracic aorta is abnormally dilated in patients with BAV, particularly in patients with moderate/severe aortic regurgitation. The maximum dilatation occurs in the ascending aorta at the level of the pulmonary artery. Thus, we suggest evaluation of the entire thoracic aorta in patients with BAV.

Management of thoracic aortic lesions - the future is endovascular

VASA ◽  
2012 ◽  
Vol 41 (3) ◽  
pp. 163-176 ◽  
Author(s):  
Weidenhagen ◽  
Bombien ◽  
Meimarakis ◽  
Geisler ◽  
A. Koeppel
Keyword(s):  
Thoracic Aorta ◽  
Clinical Decision Making ◽  
Treatment Options ◽  
Clinical Decision ◽  
Clinical Results ◽  
Treatment Modalities ◽  
Traumatic Rupture ◽  
Descending Thoracic Aorta ◽  
New Treatment ◽  
Aneurysm Dissection

Open surgical repair of lesions of the descending thoracic aorta, such as aneurysm, dissection and traumatic rupture, has been the “state-of-the-art” treatment for many decades. However, in specialized cardiovascular centers, thoracic endovascular aortic repair and hybrid aortic procedures have been implemented as novel treatment options. The current clinical results show that these procedures can be performed with low morbidity and mortality rates. However, due to a lack of randomized trials, the level of reliability of these new treatment modalities remains a matter of discussion. Clinical decision-making is generally based on the experience of the vascular center as well as on individual factors, such as life expectancy, comorbidity, aneurysm aetiology, aortic diameter and morphology. This article will review and discuss recent publications of open surgical, hybrid thoracic aortic (in case of aortic arch involvement) and endovascular repair in complex pathologies of the descending thoracic aorta.

Penetrating atherosclerotic ulcer aneurysm of the innominate artery

VASA ◽  
2009 ◽  
Vol 38 (3) ◽  
pp. 263-266 ◽  
Author(s):  
Yuan ◽  
Tager
Keyword(s):  
Conservative Treatment ◽  
Thoracic Aorta ◽  
Open Surgery ◽  
Innominate Artery ◽  
Ruptured Aneurysm ◽  
Descending Thoracic Aorta ◽  
Penetrating Atherosclerotic Ulcer ◽  
Descending Aorta

Penetrating atherosclerotic ulcer of the aorta is uncommon, and usually develops in the descending thoracic aorta. Rarely this condition involves the branch vessels of the aorta. We report a case of ruptured aneurysm of the innominate artery resulting from penetrating atherosclerotic ulcer. Open surgery was the treatment of choice for the ruptured aneurysm, while conservative treatment was recommended for the associated penetrating atherosclerotic ulcers of the descending aorta.

RadCases Plus Q&A Thoracic Imaging

2019 ◽  
Author(s):  
Carlos S Restrepo ◽  
Steven Zangan
Keyword(s):  
Thoracic Imaging
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