Magnetic resonance angiography: A comparison of techniques and applications in dogs and humans

2008 ◽  
Vol 36 (02) ◽  
pp. 1-12 ◽  
Author(s):  
A. Brühschwein ◽  
K. Rieden ◽  
U. Matis ◽  
I. Foltin
Keyword(s):  
Veterinary Medicine ◽  
Magnetic Resonance ◽  
Magnetic Resonance Angiography ◽  
Blood Vessels ◽  
Clinical Signs ◽  
Maximum Intensity Projection ◽  
Vascular Architecture ◽  
Advantages And Disadvantages ◽  
Technical Requirements ◽  
Contrast Angiography

SummaryMagnetic resonance angiography (MRA) is a non-invasive imaging technique for visualising blood vessels and blood flow. The first half of this article is a literature review of the three basic MRA techniques: Timeof-flight (TOF) angiography, phase-contrast angiography and contrast-enhanced angiography. Physical principles, technical requirements, investigated parameters, advantages and disadvantages of the methods, and the correlation between application of contrast medium and time of examination are discussed. Subsequent processing of the MR images using “maximum intensity projection“ (MIP) provided a threedimensional image of the vascular architecture and improved the anatomical orientation; however, MIP was shown to sometimes cause additional diagnostic pitfalls. Therefore, the original slices should always be consulted in addition to the MIP. The second half of this article describes the application of the different MRA methods in veterinary medicine and compares the results with MRA in human medicine. A total of 15 dogs with clinical signs that warranted further work-up using MRA, and 20 human patients requiring MRA, were included in the study. Five healthy dogs served as controls. The vascular architecture in dogs was compared with that in human patients, and the images were scrutinized for lesions that corresponded to the clinical signs. An abnormal vascular architecture was identified in eight dogs with a portosystemic shunt, which allowed targeted surgical intervention. Aneurysms, thrombi and stenoses were seen in images from human patients. Comparison of the vascular architecture in humans and dogs allowed the anatomic identification and evaluation of the visualised blood vessels in the dog. Magnetic resonance imaging is still a relatively new technique in veterinary medicine and appears to be a promising diagnostic tool for a number of disorders as the availability of high-field MRI in veterinary clinics increases.

Accurate Unsupervised 3D Segmentation of Blood Vessels Using Magnetic Resonance Angiography

2018 ◽  
pp. 71-94 ◽  
Author(s):  
Ahmed Shalaby ◽  
Ali Mahmoud ◽  
Samineh Mesbah ◽  
Maryam El-Baz ◽  
Jasjit S. Suri ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Angiography ◽  
Blood Vessels ◽  
3D Segmentation

Magnetic resonance angiography of the normal canine heart and associated blood vessels

2008 ◽  
Vol 178 (1) ◽  
pp. 130-132 ◽  
Author(s):  
Samuel Contreras ◽  
José María Vázquez ◽  
Ana De Miguel ◽  
Manuel Morales ◽  
Francisco Gil ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Angiography ◽  
Blood Vessels ◽  
Canine Heart

scholarly journals Diagnosis of supra-aortic artery stenosis: comparison of magnetic resonance angiography imaging methods with conventional digital subtraction angiography

2018 ◽  
Vol 6 (5) ◽  
pp. 1509
Author(s):  
Hale Aydin ◽  
Agildere A. Muhtesem
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Angiography ◽  
Digital Subtraction Angiography ◽  
Maximum Intensity Projection ◽  
Reconstruction Method ◽  
Digital Subtraction ◽  
Total Occlusion ◽  
Contrast Enhanced ◽  
Aortic Artery ◽  
The Individual

Background: The aim of this study was to compare conventional digital subtraction angiography (DSA) with the multi-planar reformation (MPR) and maximum intensity projection (MIP) reconstruction of servical magnetic resonance angiography (MRA) in terms of detecting supra-aortic artery stenoses.Methods: In the study, 21 patients who had underwent 3D MRA and conventional DSA were retrospectively assessed. Axial MPR, coronal MIP reconstruction and contrast enhanced 3D MRA subtraction images of a total of 333 artery segments were independently assessed by 2 separate radiologists. Conventional DSA results were accepted as gold standard results. The overall and individual Kappa values of all methods were calculated.Results: Results of the conventional DSA analysis indicated total occlusion in 9 (2.7%), severe stenosis in 16 (4.8%), moderate stenosis in 90 (27.1%), mild stenosis in 105 (31.5%) and no stenosis in 113 (33.9%) arteries. While the k values of all methods were high which demonstrated strong relationships with the DSA method; the coronal MIP reconstruction method was found to be superior to other methods. The 3D MRA subtraction method did not yield better results in any of the individual comparisons.Conclusions: Our results indicate that the coronal MIP reconstruction method has higher correlation with conventional DSA results compared to the other two methods and may be used as an accurate first-line diagnostic method for supra-aortic artery stenoses.

Probabilistic Modeling of Blood Vessels for Segmenting Magnetic Resonance Angiography Images

2017 ◽  
Vol 5 (3) ◽  
Author(s):  
Ayman El-baz ◽  
Ahmed Shalaby ◽  
Fatma Taher ◽  
Maryam El-Baz ◽  
Mohammed Ghazal ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Angiography ◽  
Blood Vessels ◽  
Probabilistic Modeling

The use of magnetic resonance angiography in stereotactic neurosurgery

1995 ◽  
Vol 82 (6) ◽  
pp. 982-987 ◽  
Author(s):  
Johan Michiels ◽  
Hilde Bosmans ◽  
Bart Nuttin ◽  
Michael Knauth ◽  
Rudi Verbeeck ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Angiography ◽  
Mr Angiography ◽  
Imaging Modality ◽  
Distortion Correction ◽  
Digital Subtraction ◽  
Stereotactic Neurosurgery ◽  
Imaging Device ◽  
Content Type ◽  
Advantages And Disadvantages

✓ The authors discuss the advantages and disadvantages of the use of magnetic resonance (MR) angiography images in stereotactic neurosurgery. Current computer programs designed to assist the neurosurgeon in the planning of stereotactic neurosurgical interventions use intraarterial digital subtraction angiography images to visualize the blood vessels. Magnetic resonance angiography is a recent technique with a number of advantages over the digital subtraction method: it is less invasive and less prone to complications; it provides truly three-dimensional data sets that can be viewed from any direction; and it can visualize both stationary and flowing tissues with the same imaging device and localizer frame. Although digital subtraction images are still superior in contrast and vascular detail, state-of-the-art high-resolution MR angiography sequences provide sufficient vascular detail for planning surgery. Contrast-enhanced MR angiography images were acquired using adapted gradient-echo sequences to compensate for flow-induced distortions; postacquisition distortion correction was not necessary. Five methods to integrate and inspect a possible trajectory in the MR angiography data are discussed. Initial clinical experience with eight patients led to the conclusion that MR angiography is a valuable imaging modality that can be integrated reliably into a stereotactic neurosurgery planning procedure.

Standardized volume-rendering of contrast-enhanced renal magnetic resonance angiography

2005 ◽  
Vol 46 (5) ◽  
pp. 497-504 ◽  
Author(s):  
Ö. Smedby ◽  
R. Öberg ◽  
B. Åsberg ◽  
H. Stenström ◽  
P. Eriksson
Keyword(s):  
Magnetic Resonance ◽  
Image Quality ◽  
Magnetic Resonance Angiography ◽  
Volume Rendering ◽  
Maximum Intensity Projection ◽  
Data Set ◽  
3D Data ◽  
Contrast Enhanced ◽  
Better Than ◽  
Good Agreement

Purpose: To propose a technique for standardizing volume-rendering technique (VRT) protocols and to compare this with maximum intensity projection (MIP) in regard to image quality and diagnostic confidence in stenosis diagnosis with magnetic resonance angiography (MRA). Material and Methods: Twenty patients were examined with MRA under suspicion of renal artery stenosis. Using the histogram function in the volume-rendering software, the 95th and 99th percentiles of the 3D data set were identified and used to define the VRT transfer function. Two radiologists assessed the stenosis pathology and image quality from rotational sequences of MIP and VRT images. Results: Good overall agreement (mean κ = 0.72) was found between MIP and VRT diagnoses. The agreement between MIP and VRT was considerably better than that between observers (mean κ = 0.43). One of the observers judged VRT images as having higher image quality than MIP images. Conclusion: Presenting renal MRA images with VRT gave results in good agreement with MIP. With VRT protocols defined from the histogram of the image, the lack of an absolute gray scale in MRI need not be a major problem.

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