Dynamic MR digital subtraction angiography using contrast enhancement, fast data acquisition, and complex subtraction

Wang, Yi; Johnston, Donald L.; Breen, Jerome F.; Huston, John; Jack, Clifford R.; Julsrud, Paul R.; Kiely, Michael J.; King, Bernard F.; Riederer, Stephen L.; Ehman, Richard L.

doi:10.1002/mrm.1910360408

Cited by 146 publications

(117 citation statements)

References 11 publications

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“…However, practically, the background tissue signal level changes over time, either because of the leakage of the contrast agent into the tissue or because of the motion of the patient. Patient motion is particularly a problem for complex subtraction, which is necessary for correcting the partial-volume effects in projection imaging (7). Therefore, it is desirable to have no background signal contribution in projection imaging.…”

Section: Discussionmentioning

confidence: 99%

Comparison of matched‐filtered two‐dimensional projection and elliptical centric‐ordered three‐dimensional contrast‐enhanced magnetic resonance angiography

Huang

Merchant

Wright

2004

Magnetic Resonance Imaging

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Purpose:To compare the image quality of matched-filtered two-dimensional projection magnetic resonance angiography (MRA) and elliptical centric-ordered (EC) three-dimensional MRA. Materials and Methods:Signal-to-noise ratios (SNRs) of matched-filtered two-dimensional projection and EC threedimensional MRA are developed theoretically and compared by clinical studies, in which 10 -20 mL of gadolinium (Gd) was injected at 1.5 mL/second. The artery-vein contrast in twodimensional projection MRA was managed by manually selecting specific templates for the matched filters. Results:The SNR of matched-filtered two-dimensional projection MRA is superior to that of EC three-dimensional MRA for vessels wider than one pixel due to the integral effect. The artery-vein contrast can be managed flexibly in two-dimensional projection MRA by choosing different templates for the matched filter, while the artery-vein contrast in EC three-dimensional MRA is solely determined by the timing to start the acquisition. Conclusion:Matched-filtered two-dimensional projection MRA provides comparable image quality and is a flexible alternative to EC three-dimensional MRA in applications where contrast timing is difficult and temporal information is of interest. ELLIPTICAL CENTRIC-ORDERED (EC) three-dimensional contrast-enhanced magnetic resonance angiography (MRA) has become established as a minimally invasive vascular imaging modality in clinical practice (1). It provides a three-dimensional visualization of the arterial vasculature with good venous suppression and high signal-to-noise ratio (SNR) due to the centric k-space ordering and an extended acquisition time. An accurate timing of the acquisition relative to the peak contrast enhancement is crucial for optimal SNR and artery-vein contrast (2). The timing is usually measured either by a test bolus (3) or by a real-time triggering tool (4). In any case, there could be errors due to the complex blood flow patterns among the patient populations (5), which may cause venous contamination and/or loss of SNR. The other concern of EC three-dimensional MRA is that the signal intensities of small vessels and vessel edges are lower than those of large vessels (6). This is due to their relatively higher signal contribution from the high frequencies in k-space, which are scanned at reduced contrast concentration following first pass.Alternatively, two-dimensional projection MRA has been applied in the situations where timing is difficult, such as for imaging the runoff arteries of ankles and feet (7). Two-dimensional projection images are acquired repeatedly at a high temporal resolution. The arterial conspicuity and SNR can be improved by subtraction and matched filtering (8). However, the work on two-dimensional projection MRA has focused primarily on acquiring the high temporal information (9). The image quality is usually thought to be inferior to that of EC three-dimensional MRA even after postprocessing.In this study, we compare the image quality of EC three-dimensional MRA and two-dimension...

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Section: Discussionmentioning

confidence: 99%

Comparison of matched‐filtered two‐dimensional projection and elliptical centric‐ordered three‐dimensional contrast‐enhanced magnetic resonance angiography

Huang

Merchant

Wright

2004

Magnetic Resonance Imaging

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“…Based on maximizing this image quality, an iterative algorithm is used to select mask images and arterial phase images to generate a linearly filtered image of the highest quality (Eq. [2]). Branch 1st 2nd 1st 2nd 1st 2nd 1st 2nd Manual 44 30 7 43 25 3 44 31 4 45 22 2 Reader 1 Automatic 44 36 6 43 29 2 43 29 6 43 18 2 Manual 42 27 3 40 32 1 35 26 4 43 26 3 Reader 2 Automatic 41 32 5 41 33 1 37 30 5 43 The automatic image selection algorithm presented in this article works quite well in suppressing common motion artifacts in dynamic 2D projection MRA that consists of a crowd-like background noise of low signal intensity.…”

Section: Discussionmentioning

confidence: 99%

“…To assess this automated method, two radiologists (MRP, HE), blinded to the filtering process, accessed the automatically and the manually filtered images (21) side-by-side using five scales: one image is substantially better than [2], modestly better than [1], approximately the same as [0], modestly worse than [Ϫ1], substantially worse than [Ϫ2] the other. The orders of the image pair were randomized using a computer and two readers evaluated the images independently.…”

Section: Image Evaluationmentioning

confidence: 99%

“…Among data acquisition techniques for CEMRA, the time-resolved strategy offers a very useful option for many situations because of the elimination of the cumbersome timing of imaging to the contrast bolus arrival (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). The time-resolved CEMRA generates time series images in a manner similar to fluoroscopic X-ray angiography, where image postprocessing has been used frequently to improve vasculature display (14,15).…”

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confidence: 99%

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Automatic selection of mask and arterial phase images for temporally resolved MR digital subtraction angiography

Kim

Prince

Zabih

et al. 2002

Magnetic Resonance in Med

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For time-resolved background-subtracted contrast-enhanced magnetic resonance angiography, the bright and sparse arterial signal allows unique identification of contrast bolus arrival in the arteries. This article presents an automatic filtering algorithm using such arterial characterization for selecting arterial phase images and mask images to generate an optimal summary arteriogram. A paired double-blinded comparison demonstrated that this automatic algorithm is as effective as the manual process.Magn Contrast-enhanced magnetic resonance angiography (CEMRA) has become a routine clinical tool for pretreatment mapping of vasculature (1). Among data acquisition techniques for CEMRA, the time-resolved strategy offers a very useful option for many situations because of the elimination of the cumbersome timing of imaging to the contrast bolus arrival (2-13). The time-resolved CEMRA generates time series images in a manner similar to fluoroscopic X-ray angiography, where image postprocessing has been used frequently to improve vasculature display (14,15). For example, from the time-series images all mask images and arterial phase images can be summoned into one image of greater vascular detail with high signal-tonoise ratio (SNR) that is particularly useful for presentation in a surgical operation room where video display may not be available. Linear filtering techniques such as the matched filters can be used to produce a summation image (15,16) and have been attempted in time-resolved or dynamic CEMRA to generate a summary arteriogram (17-21). In practice, the major challenge for summarizing time series images is to identify the contrast bolus arrival and to avoid motion-corrupted mask images and arterial phase images that propagate severe motion artifacts into the final summation image (21). So far, this avoidance of motioncorrupted images and selection of optimal arterial phase and mask images for summation have been performed through a tedious manual procedure (21).Here we report an algorithm that can fully automate the linear filtering process, i.e., to select the set of arterial phase images and the set of mask images such that the subtracted image from the former to the latter is of the best quality. We describe in detail 1) how to quantify the notion of "image quality," and 2) how to effectively select the mask and arterial phase images based on the quantified measure of quality. POSTPROCESSING TECHNIQUES Problem StatementOur approach is basically an automated version of linear filtering that selects a mask image set and an arterial phase image set to generate a linear filtered image. For a given time series of images (I n , n ϭ 1ϳ n max , n max ϭ 35 -40, the total number of images in the time series), indexed by x and y, we want to select the mask image set (M) and the arterial phase image set (A), such that the subtracted or filtered image (S h ) is of "best quality," where S h is given by:where ͉M͉ and ͉A͉ are the number of mask images and arterial phase images, respectively. Note that all the arithmetic ...

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“…Because two-dimensional FLASH images only show a very limited section of the blood vessel, a variant of the FLASH sequence without slice selection was implemented (18). In this projection MR-DSA mode, which could also be switched on interactively, at otherwise unchanged imaging parameters, a non-selective rf pulse was used for excitation.…”

Section: Tracking Pulse Sequencementioning

confidence: 99%

MR‐guided intravascular procedures: Real‐time parameter control and automated slice positioning with active tracking coils

Bock

Volz

Zühlsdorff

et al. 2004

Magnetic Resonance Imaging

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Purpose: To implement and optimize a real-time pulse sequence and user interface to perform intravascular interventions using active catheter tracking. Materials and Methods:In magnetic resonance (MR)-guided interventions, small radio-frequency coils can be used to rapidly determine the device position (active tracking). In this work, active catheter tracking was combined with a dedicated real-time pulse sequence and user interface. The pulse sequence offered the imaging contrasts fast low angle shot (FLASH), true Fast imaging with steady state precession (TrueFISP), and projection MR digital subtraction angiography (MR-DSA), which could be selected by the radiologist from within the scanner room at any time during the intervention. Automatic slice positioning was added to the real-time pulse sequence so that the location of the tracking coils defined the image slice position and orientation. The technique was assessed in phantoms and animal experiments.Results: At a reaction time of 24 msec and a frame rate of three images per second, the movement of an active intravascular catheter could be monitored in the aorta and the renal arteries of a pig. With interactive contrast and orientation changes, the renal vasculature could be assessed by a fully MR-guided catheterization in less than 10 minutes. Conclusion:With carefully designed active catheters, a dedicated user interface, and an optimized pulse sequence intravascular interventions can successfully be performed by a single operator from within the MR scanner room.

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Dynamic MR digital subtraction angiography using contrast enhancement, fast data acquisition, and complex subtraction

Cited by 146 publications

References 11 publications

Comparison of matched‐filtered two‐dimensional projection and elliptical centric‐ordered three‐dimensional contrast‐enhanced magnetic resonance angiography

Comparison of matched‐filtered two‐dimensional projection and elliptical centric‐ordered three‐dimensional contrast‐enhanced magnetic resonance angiography

Automatic selection of mask and arterial phase images for temporally resolved MR digital subtraction angiography

MR‐guided intravascular procedures: Real‐time parameter control and automated slice positioning with active tracking coils

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