Dynamic MR venography: An intrinsic benefit of time‐resolved MR angiography

Du, Jiang; Thornton, Frank J.; Mistretta, Charles A.; Grist, Thomas M.

doi:10.1002/jmri.20716

Cited by 20 publications

(9 citation statements)

References 22 publications

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“…We believe that this work represents an advance over the study of Du et al (22). The intrinsic spatial resolution of the images of the lower legs obtained in this study (1.0 mm 3 isotropic vs 1.0 ϫ 1.0 ϫ 1.5 mm) within a comparable time frame (5.4 vs 4.3 seconds) but shorter total acquisition time per image (21.6 vs 70.0 seconds) was superior.…”

Section: Technical Developments: Time-of-arrival Mapping At Mr Angiogsupporting

confidence: 51%

“…This improvement was due to the greater than 10-fold acceleration facilitated by the parallel acquisition and the homodyne of the Cartesian acquisition with projection-reconstruction-like sampling in our study. This examination also extends beyond separating veins from arteries, as in the Du et al study (22), to also enable accurate determination of the absolute TOA value for all enhancing vessels, with precision in the range of 1 second. To this end, we believe that in this work we have identified a more detailed level of evaluating time-resolved MR angiographic findings compared with those used previously.…”

Section: Technical Developments: Time-of-arrival Mapping At Mr Angiogmentioning

confidence: 93%

“…At ultrasonography, the TOA of contrast material and the peak signal have been determined after the intravenous administration of contrast material and converted into a color display (21). At MR imaging, investigators have used a time series of 3D contrast-enhanced angiograms as input in a process used to segment voxels of the vasculature into two groups-arterial and venous-on the basis of binary binning of the contrast material arrival time (22). This segmentation process was used to isolate the venous system.…”

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confidence: 99%

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Time-of-Arrival Mapping at Three-dimensional Time-resolved Contrast-enhanced MR Angiography

Riederer

Haider²,

Borisch

2009

Radiology

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This study was HIPAA compliant and institutional review board approved, and informed consent was obtained from all volunteers. The authors describe a method for generating a time-of-arrival (TOA) map of intravenously administered contrast material, as observed in a time series of three-dimensional (3D) contrast material-enhanced magnetic resonance (MR) angiograms. The method may enable visualization and interpretation, on one 3D image, of the temporal enhancement patterns that occur in the vasculature. Colorization of TOA values may further aid interpretation. The quality of the results depends not only on the adequacy of the frame rate, spatial resolution, and signal-to-noise ratio of the MR image acquisition method but also on the accuracy and clarity with which the leading edge of the contrast material bolus is depicted. The criteria for optimizing these parameters are described. The TOA mapping technique is demonstrated by using vascular studies of the hands, brain, and lower leg regions. Note: This copy is for your personal, non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, use the Radiology Reprints form at the end of this article. Since the introduction of contrast material-enhanced magnetic resonance (MR) angiography more than a decade ago (1), there have been steady improvements in the technique. Early advances include the reduction in repetition times for three-dimensional (3D) sequences (2), the development of centric view orders (3,4), and methods for synchronizing image acquisitions with the arterial phase of contrast enhancement (5-7). There has also been interest in generating a time series of 3D image sets (8), but this was subject to a trade-off in temporal resolution for adequate spatial resolution (9).In the late 1990s, several methods of parallel imaging (10,11) that facilitated a reduction in acquisition time for a given spatial resolution were developed. These methods were initially applied along one phase-encoding direction, and an early application was contrast-enhanced MR angiography (12,13). However, parallel acquisition was also shown to be applicable along the two phase-encoding directions of a 3D Fourier transform acquisition (14). Moreover, for a given acceleration factor, there will be a considerably lower penalty in lost signal-to-noise ratio (SNR) if one achieves the acceleration cumulatively by applying smaller accelerations in each of the two phase-encoding directions as opposed to applying the acceleration factor solely in one direction. Thus, for 3D contrast-enhanced MR angiography, twodimensional acceleration factors as high as five to eight can be routinely used (15)(16)(17)(18)(19).A consequence of the reduced acquisition time is that a series of highspatial-resolution 3D images can now be generated within a time period during which only one image might have been obtained previously. With this increased speed, it has become possible to visualize, with high spatial resolution, the dynamic processes that occur within ...

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Section: Technical Developments: Time-of-arrival Mapping At Mr Angiogsupporting

confidence: 51%

Section: Technical Developments: Time-of-arrival Mapping At Mr Angiogmentioning

confidence: 93%

mentioning

confidence: 99%

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Time-of-Arrival Mapping at Three-dimensional Time-resolved Contrast-enhanced MR Angiography

Riederer

Haider²,

Borisch

2009

Radiology

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“…For the same approximate 20-second acquisition time per image, CAPR provides images at a three to four times higher frame rate versus those previously reported (15,41,42). For the same approximate 5-second frame time, the 20- (43,44). CAPR avoids k-space interpolation of time-resolved imaging of contrast kinetics (or TRICKS) (10) and extensive sampling of peripheral k-space after central k-space of time-resolved angiography with interleaved stochastic trajectories (or TWIST) (45), characteristics that can degrade the sharpness in portraying the leading edge of the contrast material bolus (46).…”

Section: Discussionmentioning

confidence: 75%

Peripheral Vasculature: High-Temporal- and High-Spatial-Resolution Three-dimensional Contrast-enhanced MR Angiography

Haider

Glockner²,

Stanson

et al. 2009

Radiology

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Purpose:To prospectively evaluate the feasibility of performing high-spatial-resolution (1-mm isotropic) time-resolved three-dimensional (3D) contrast material-enhanced magnetic resonance (MR) angiography of the peripheral vasculature with Cartesian acquisition with projectionreconstruction-like sampling (CAPR) and eightfold accelerated two-dimensional (2D) sensitivity encoding (SENSE). Materials and Methods:All studies were approved by the institutional review board and were HIPAA compliant; written informed consent was obtained from all participants. There were 13 volunteers (mean age, 41.9; range, 27-53 years). The CAPR sequence was adapted to provide 1-mm isotropic spatial resolution and a 5-second frame time. Use of different receiver coil element sizes for those placed on the anterior-to-posterior versus left-to-right sides of the field of view reduced signal-to-noise ratio loss due to acceleration. Results from eight volunteers were rated independently by two radiologists according to prominence of artifact, arterial to venous separation, vessel sharpness, continuity of arterial signal intensity in major arteries (anterior and posterior tibial, peroneal), demarcation of origin of major arteries, and overall diagnostic image quality. MR angiographic results in two patients with peripheral vascular disease were compared with their results at computed tomographic angiography. Results:The sequence exhibited no image artifact adversely affecting diagnostic image quality. Temporal resolution was evaluated to be sufficient in all cases, even with known rapid arterial to venous transit. The vessels were graded to have excellent sharpness, continuity, and demarcation of the origins of the major arteries. Distal muscular branches and the communicating and perforating arteries were routinely seen. Excellent diagnostic quality rating was given for 15 (94%) of 16 evaluations. Conclusion:The feasibility of performing high-diagnostic-quality timeresolved 3D contrast-enhanced MR angiography of the peripheral vasculature by using CAPR and eightfold accelerated 2D SENSE has been demonstrated.

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“…Flow artifacts may arise with time-of-flight techniques and require saturation and long acquisition times. More recently, two methods enhanced by contrast 3 in which the arterial phase is subtracted from the venous-arterial equilibrium phase 31 as well as direct contrast-enhanced venous phase 28,32 have been shown to be effective in diagnosing iliac vein compression.…”

Section: Discussionmentioning

confidence: 99%