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Query: EC:3.4.24.59 (MIP)
 4,906 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Technical characteristics, acquisition modality and data representations as well as examination protocols and main clinical applications of spiral CT angiography (CTA) are described. The different methods of 2D (MPR, CPR) and 3D (SSD, MIP) data display and their advantages and limitations were investigated. We describe the examination technique representing an important tool to achieve good image quality and to make the correct diagnosis. The clinical effectiveness and the main applications in the body were studied. CTA already has a clinical role for arterial system study, while it is less indicated in the venous system because good and continuous contrast agent opacification is difficult to obtain. In our preliminary experience, CTA can be considered an effective alternative to DSA in the assessment of vascular conditions because it is easier to perform, more rapid and less invasive.
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PMID:[Angiography with spiral computed tomography. The basic principles and clinical potentials]. 759 24

This study was aimed to assess the comparative capabilities of CT angiography (CTA) and DSA in diagnosing aneurysms in different sites in a series of 20 patients. Volumes were measured during intravenous contrast agent infusion and images were then edited and reformatted as 2D and 3D displays (MPR, SSD, MIP techniques). Some of the main semiologic patterns of aneurysms were considered and the diagnostic accuracy of the 3 reconstruction techniques was assessed and compared with that of axial CT and DSA. Abdominal aortic aneurysms were analyzed separately to study the involvement of main collateral vessels. The best results were obtained with MIP and MPR in the assessment of aneurysm extent and neck. MPR is the only technique which could depict the thrombus and the best technique to demonstrate the relationships between aneurysm and adjacent structures. The MIP technique depicts calcifications and is the method of choice to demonstrate the involvement of collateral vessels by abdominal aortic aneurysms. SSD permits good assessment of the neck and of the longitudinal extent of the aneurysms but is severely limited in the analysis of the other variables.
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PMID:[Aneurysmal disease. Initial clinical experience with spiral computerized tomography angiography]. 761 2

It is possible to improve on the low skirt selectivity of the slice sensitivity profile (SSP) in spiral CT by interpolation of the raw data or suitable image after-processing. We determined the SSP function of spiral CT by means of a plexiglas phantom which we subsequently modified empirically-mathematically by a correction function until we obtained maximum possible skirt selectivity and smallest possible FWHM (= full width at half maximum) of the corrected image data set. The corrected image data set was obtained by bilateral convolution of a real image data set with a correction function. This resulted in most cases in a more realistic imaging of the angiographic morphology when applied to SSD and MIP (3D) reconstructions of a. mesenterica sup. and tr. coeliacus from spiral CT data sets, compared with the original data sets.
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PMID:[Spiral CT angiography: computed improvement of the slice thickness profile]. 867 83

3D angiography is a true technical revolution that allows improvement in the quality and safety of diagnostic and endovascular treatment procedures. 3D angiography images are obtained by reconstruction of a rotational angiography acquisition done on a C-arm (GE Medical Systems) spinning at 40 degrees per second. The carotid or vertebral selective injection of a total of 15 ml of non-ionic contrast media at 3 ml/sec over 5 seconds allows the selection of the "arterial phase". Four hundred sixty 3D angiographic studies were performed from December 1996 to September 1998 on 260 patients and have been analyzed in MIP (Maximum Intensity Projection) and SSD (Shaded Surface Display) views. The exploration of intracranial aneurysms is simplified and only requires, for each vascular axis, a biplane PA and Lateral run followed by a single rotational angiography run. The 3D angiography image is available on the workstation's screen (Advantage Workstation 3.1, GE Medical Systems) in less than 10 minutes after the acquisition of the rotational run. It therefore allows one to analyze, during the intervention, the aneurysm's angioarchitecture, in particular the neck, and select the best therapeutic technique. When endovascular treatment is the best indication, 3D angiography allows one to define the optimal angle of view and accurately select the microcoils dimensions. 3D angiography replaces the multiple oblique views that used to be required to analyze the complex aneurysms and therefore allows a reduction of the total contrast medium quantity, the patient X-ray dose and the length of the intervention time which is a safety factor. Also, in particular for complex cases, it brings additional elements complementing the results of standard 2D DSA and rotational angiograms. In the cervical vascular pathology, 3D angiography allows for a better assessment of the stenosis level and of dissection lesions. Our current research activities focus on the matching without stereotactic frame between 3D X-ray angiography and volumetric MR acquisition, which should allow us to improve the treatment of intracerebral arterio-venous malformations (AVMs).
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PMID:3D angiography. Clinical interest. First applications in interventional neuroradiology. 1004 68

The authors have presented several 3-D CT imaging techniques that may be useful in dentistry. MPR and dental MPR provides cross-sectional images of the jaws and the dental arches, and its utility in implant treatment planning is widely recognized. SSD allows the clinician to visualize the surface of an anatomic structure that is selected by a threshold value. Volume rendering is a powerful and flexible three-dimensional imaging technique that can create various unique images. MIP may be useful in contrast-enhanced CT examinations, such as sialography. Model production and virtual reality three-dimensional imaging may become major techniques in the near future. Although the increased radiation dose to the patients has to be considered, future imaging demands will bring more access to 3-D CT imaging by dental patients and, with adequate three-dimensional rendering techniques, more accurate diagnosis and treatment planning.
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PMID:Three-dimensional computed tomography imaging in dentistry. 1074 Jul 75

Computed tomography (CT) and intraarterial cerebral angiography are essential methods in early diagnosis of cerebral vascular malformations. In recent years however non-invasive or minimally invasive methods like MR angiography and CT angiography (CTA), which could potentially replace angiography, have been developed. The aim of presented study is to demonstrate our own experience in application of CTA in early diagnosis of cerebral vascular malformations. The material consists of 86 CTA examinations performed shortly after non-traumatic intracranial haemorrhage. Angiographic correlation has been available in 23 patients and surgical one--in 31 cases. CTA studies began with serio-CT to select the optimal time between contrast injection and CT scanning. After that 100-120 ml of non-ionic contrast medium was injected intravenously (5 ml per sec.) and spiral CT acqusition was performed with the delay calculated on the basis of the serio-CT. The obtained images were postprocessed on the workstation using always MIP and in many cases also SSD and VRT reconstructions. Vascular malformations have been diagnosed in 44 of 86 CTA studies including 38 patients with aneurysms (total number 51) and 6 patients with AVMs. In 17 cases the diameter of the aneurysm did not exceed 5 mm. In all surgical cases the CTA diagnosis of the aneurysm has been confirmed. There was however one false-negative case. On the other hand in 7 patients CTA revealed the small aneurysm, despite unclear angiographic appearance. In 2 of 6 patients with CTA suspicion of AVM this diagnosis has been excluded either by angiography or surgery. Comparison of CTA and angiography in 22 aneurysms showed in 17 cases superiority of CTA in evaluation of aneurysmal neck and the relationship between aneurysm and adjacent vessels (especially with VRT and SSD reconstructions). In patients with AVMs however the evaluation of supplying and draining vessels was better with angiography. On the base of our material we can conclude that CTA is very efficient in detecting and evaluating the aneurysms. We believe that CTA can replace angiography if it reveals aneurysm in a site corresponding with location of haemorrhage on CT. In patients with suspicion of AVM value of CTA is doubtful and angiography remains the method of choice.
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PMID:Our own experience with CT angiography in early diagnosis of cerebral vascular malformations. 1145 55

The purpose of this investigation was to analyze three-dimensional images of the optic nerve obtained by magnetic resonance angiography (MRA) in cases of anterior communicating artery aneurysm and craniopharingioma. Four ruptured anterior communicating artery aneurysms, five non-ruptured anterior communicating artery aneurysms and two craniopharingiomas were examined. The images were taken using MR/i Hispeed Plus 1.5T Infinity version, and analyzed by Advantage Work station AW4.1. The routine MR imaging parameters are shown in Table. The imaging time was about 10 minutes. Analysis was made by reformation of images parallel to the optic nerve obtained from the original MRA images. The optic nerve and brain tumor were traced with paintbrush from one sheet to another of the reformed images after subtraction of the blood vessels around the anterior communicating artery in these reformed images, and then three-dimensional images were constructed. Three-dimensional images of the blood vessels were reconstructed from MIP (maximum intensity projection) images using the threshold method. The optic nerve and anterior communicating arterial aneurysm or brain tumor were both observed in the overlapped 3D-SSD (shaded surface display) images. The analysis time was about 15 minutes. Three-dimensional images of the optic nerve and anterior communicating artery aneurysm or brain tumor were able to be made in all cases. As a preoperative investigation for anterior communicating artery aneurysm or suprasellar brain tumor, we considered that three-dimensional imaging of the optic nerve is useful in the operative approach because the optic nerve acts as a merkmal for the anterior communicating aneurysm or brain tumor.
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PMID:[Three-dimensional imaging of the optic nerve using magnetic resonance angiography--application to anterior communicating artery aneurysm and craniopharingioma]. 1583 May 41