Skip to main content
Advertisement

Main menu

  • Home
  • Content
    • Current Issue
    • Publication Preview--Ahead of Print
    • Past Issue Archive
    • Case of the Week Archive
    • Classic Case Archive
    • Case of the Month Archive
  • For Authors
  • About Us
    • About AJNR
    • Editors
    • American Society of Neuroradiology
  • Submit a Manuscript
  • Podcasts
    • Subscribe on iTunes
    • Subscribe on Stitcher
  • More
    • Subscribers
    • Permissions
    • Advertisers
    • Alerts
    • Feedback
  • Other Publications
    • ajnr

User menu

  • Subscribe
  • Alerts
  • Log in

Search

  • Advanced search
American Journal of Neuroradiology
American Journal of Neuroradiology

American Journal of Neuroradiology

  • Subscribe
  • Alerts
  • Log in

Advanced Search

  • Home
  • Content
    • Current Issue
    • Publication Preview--Ahead of Print
    • Past Issue Archive
    • Case of the Week Archive
    • Classic Case Archive
    • Case of the Month Archive
  • For Authors
  • About Us
    • About AJNR
    • Editors
    • American Society of Neuroradiology
  • Submit a Manuscript
  • Podcasts
    • Subscribe on iTunes
    • Subscribe on Stitcher
  • More
    • Subscribers
    • Permissions
    • Advertisers
    • Alerts
    • Feedback
  • Follow AJNR on Twitter
  • Visit AJNR on Facebook
  • Follow AJNR on Instagram
  • Join AJNR on LinkedIn
  • RSS Feeds
Research ArticleINTERVENTIONAL

Inflow Jet Patterns of Unruptured Cerebral Aneurysms Based on the Flow Velocity in the Parent Artery: Evaluation Using 4D Flow MRI

K. Futami, T. Kitabayashi, H. Sano, K. Misaki, N. Uchiyama, F. Ueda and M. Nakada
American Journal of Neuroradiology July 2016, 37 (7) 1318-1323; DOI: https://doi.org/10.3174/ajnr.A4704
K. Futami
aFrom the Department of Neurosurgery, Mattoh-Ishikawa Central Hospital (K.F.), Ishikawa, Japan
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for K. Futami
T. Kitabayashi
bDepartments of Neurosurgery (T.K., H.S., K.M., N.U., M.N.)
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for T. Kitabayashi
H. Sano
bDepartments of Neurosurgery (T.K., H.S., K.M., N.U., M.N.)
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for H. Sano
K. Misaki
bDepartments of Neurosurgery (T.K., H.S., K.M., N.U., M.N.)
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for K. Misaki
N. Uchiyama
bDepartments of Neurosurgery (T.K., H.S., K.M., N.U., M.N.)
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for N. Uchiyama
F. Ueda
cRadiology (F.U.), Kanazawa University School of Medicine, Ishikawa, Japan.
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for F. Ueda
M. Nakada
bDepartments of Neurosurgery (T.K., H.S., K.M., N.U., M.N.)
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for M. Nakada
  • Article
  • Figures & Data
  • Info & Metrics
  • References
  • PDF
Loading

Abstract

BACKGROUND AND PURPOSE: Inflow jet characteristics may be related to aneurysmal bleb formation and rupture. We investigated the visualization threshold on the basis of the flow velocity in the parent artery to classify the inflow jet patterns observed on 4D flow MR imaging.

MATERIALS AND METHODS: Fifty-seven unruptured aneurysms (24 bifurcation and 33 sidewall aneurysms) were subjected to 4D flow MR imaging to visualize inflow streamline bundles whose velocity exceeded visualization thresholds corresponding to 60%, 75%, and 90% of the maximum flow velocity in the parent artery. The shape of the streamline bundle was determined visually, and the inflow jet patterns were classified as concentrated, diffuse, neck-limited, and unvisualized.

RESULTS: At the 75% threshold, bifurcation aneurysms exhibited a concentrated inflow jet pattern at the highest rate. At this threshold, the inflow jets were concentrated in 13 aneurysms (group C, 22.8%), diffuse in 18 (group D, 31.6%), neck-limited in 11 (group N, 19.3%), and unvisualized in 15 (group U, 26.3%). In 16 (28.1%) of the 57 aneurysms, the inflow jet pattern was different at various thresholds. Most inflow parameters, including the maximum inflow velocity and rate, the inflow velocity ratio, and the inflow rate ratio, were significantly higher in groups C and D than in groups N and U.

CONCLUSIONS: The inflow jet pattern may depend on the threshold applied to visualize the inflow streamlines on 4D flow MR imaging. For the classification of the inflow jet patterns on 4D flow MR imaging, the 75% threshold may be optimal among the 3 thresholds corresponding to 60%, 75%, and 90% of the maximum flow velocity in the parent artery.

The inflow jets of cerebral aneurysms have been characterized as flow structures composed of strongly directed inflow with higher speeds than in other parts of the aneurysm.1,2 Computational fluid dynamics analyses by using human cerebral aneurysm models suggested that inflow jets may be related to bleb formation and aneurysmal rupture.3⇓–5 Cebral et al3 reported that most blebs formed at sites where the inflow jet impacted the aneurysmal wall, and they qualitatively classified the inflow jets of ruptured and unruptured cerebral aneurysms into concentrated and diffuse inflow jets.3⇓–5 They found that most ruptured aneurysms featured concentrated inflow jets, while diffuse inflow jets tended to be seen in unruptured aneurysms.4,5 This finding suggests that bleb formation and aneurysm rupture may be attributable to a degenerative change in the aneurysm wall exposed to the increased hemodynamic stress exerted by the inflow jet. Therefore, the assessment of inflow jet patterns and quantitative estimation of the inflow hemodynamics may contribute to a more precise prediction of the risk for bleb formation and aneurysm rupture.

Computational fluid dynamics analysis uses human aneurysm models based on a number of assumptions and approximations regarding blood properties, vessel wall compliance, and flow conditions.3⇓⇓⇓⇓–8 For the quantitative evaluation of the hemodynamics in real human cerebral aneurysms, 4D flow MR imaging, which is based on time-resolved 3D cine phase-contrast MR imaging techniques, has been used.9⇓⇓⇓⇓⇓⇓⇓⇓⇓⇓–20 In this study, we investigated the visualization threshold on the basis of the flow velocity in the parent artery to classify the inflow jet patterns of unruptured cerebral aneurysms on 4D flow MR imaging. We applied different thresholds to visualize the inflow streamlines, evaluated the inflow jet patterns, and examined the relationship between the inflow jet pattern and the inflow hemodynamics.

Materials and Methods

This study was approved by the ethics committee of Mattoh-Ishikawa Central Hospital. Prior written informed consent was obtained from all patients.

Materials

We acquired 4D flow MR images in 68 patients with 72 unruptured cerebral aneurysms. Excluded from our study were 7 aneurysms whose poor-quality images were inadequate for evaluation due to motion artifacts21 during the systole phase of the cardiac cycle and 8 aneurysms with a maximum diameter of <4.0 mm or a neck size of <2.0 mm because the spatial resolution is limited on 4D flow MR imaging.20,22 Consequently, this study included 53 patients (22 men, 31 women) ranging in age from 51 to 86 years (mean, 71.6 ± 9.0 years) with 57 unruptured cerebral aneurysms (24 bifurcation and 33 sidewall aneurysms). Of the aneurysms, 4 were located on the cavernous, and 15, on the paraclinoid segment of the ICA; 14, on the ICA segment branching the posterior communicating artery; 1, on the ICA bifurcation; 6, on the bifurcation of the anterior cerebral artery and the anterior communicating artery; 14, on the MCA bifurcation; and 3, on the basilar artery bifurcation. The maximum diameters of the aneurysms and their neck sizes were 6.8 ± 3.1 mm (range, 4.0–17 mm) and 5.0 ± 2.2 mm (range, 2.0–13.7 mm), respectively.

MR Imaging

MR imaging was performed on a 1.5T scanner (Magnetom Avanto; Siemens, Erlangen, Germany) with a slew rate of 125 T/m/s and an 8-channel head array coil. The vascular geometry was assessed on 3D TOF MRA. The scanning parameters were TR/TE/NEX, 35 ms/7.15 ms/average 1; flip angle, 22°; FOV, 150 × 123 mm; z-coverage, 45.6 mm; 0.6-mm thickness; 3 slabs; 30 sections/slab; slab interval, −4.2 mm (ie, overlapping slab acquisition, 4.2 mm); matrix, 256 × 168 (512 × 336 with zero-filling interpolation processing); voxel size, 0.59 × 0.73 × 0.6 mm (0.295 × 0.365 × 0.6 mm with zero-filling); bandwidth, 87 Hz/px; imaging time, 4 minutes 53 seconds; transaxial direction.

Blood flow analysis was performed on 4D flow MR imaging scans. The parameters were TR/TE/NEX, 33.05 ms/5.63 ms/average 1; flip angle, 22°; FOV, 200 × 200 mm; 0.8-mm thickness; 1 slab; 24–26 sections/slab; z-coverage, 19.2 mm; matrix, 192 × 192; no interpolation processing; voxel size, 1.04 × 1.04 × 0.8 mm; velocity-encoding, 80 cm/s; bandwidth, 434 Hz/px; parallel imaging with reduction factor, 2; imaging time, 20–30 minutes depending on the patient's heart rate; transaxial direction; retrospective gating with electrocardiogram; 20 phases. We selected a velocity-encoding of 80 cm/s to visualize streamlines whose velocity exceeded a chosen visualization threshold based on the maximum flow velocity in the parent artery.

On the basis of the 3D TOF MRA datasets, the vascular wall was constructed by using the region-growing method23 and the “Marching Cubes” method.24 The 3D datasets obtained by 4D flow MR imaging were converted to pixel datasets at a spatial resolution of 0.5 × 0.5 × 0.5 mm by using a function featured on commercially available software (Flova II, Version 2.9.15.0; R'tech, Hamamatsu, Japan) to visualize 3D flow information.

Data Analysis

With a Flova II function, an arbitrary percentage value of the maximum flow velocity in the parent artery can be selected as the visualization threshold. We set 60%, 75%, and 90% as the thresholds to evaluate the role they play in the visualization of the inflow jet patterns. The inflow jet was visualized as a bundle of streamlines whose velocity exceeded the threshold at the aneurysmal orifice. The 57 aneurysms were classified by visual inspection into 4 groups based on the shape of the streamline bundle and the site on the aneurysmal wall impacted by the inflow streams (Fig 1). Group C exhibited a concentrated inflow jet with intrusion into the aneurysmal dome without dispersion in 20% of the width of the streamline bundle at the aneurysmal orifice and an impact at the aneurysm wall at a site half-way up the aneurysm height (Fig 1, Concentrated). Group D comprised aneurysms with a diffuse inflow jet defined as an inflow jet intruding into the aneurysmal dome with dispersion in >20% of the width of the streamline bundle at the aneurysm orifice and an impact on the aneurysmal wall at a site more than half-way up the aneurysm height (Fig 1, Diffuse). The 20% value was chosen to accommodate measurement errors of the width of the inflow streamline bundle. Group N consisted of aneurysms with neck-limited inflow jets defined as inflow streamlines that impacted the aneurysm wall at a site between the neck and the lower half of the aneurysm height irrespective of the shape of the inflow streamline bundle (Fig 1, Neck-limited). Group U aneurysms had unvisualized inflow streamlines (Fig 1, Unvisualized).

Fig 1.
  • Download figure
  • Open in new tab
  • Download powerpoint
Fig 1.

Classification of inflow jet patterns visualized on 4D flow MR images. Concentrated: An aneurysm on the anterior communicating artery with a concentrated inflow jet defined as a bundle of inflow streamlines intruding into the aneurysmal dome without dispersion in 20% of the width of the streamline bundle at the aneurysmal orifice and impacting the aneurysmal wall at a site more than half-way up the aneurysm height. Diffuse: A sidewall aneurysm on the ICA with a diffuse inflow jet defined as inflow streamlines intruding into the aneurysmal dome with dispersion in >20% of the width of the streamline bundle at the aneurysmal orifice and impacting the aneurysmal wall at a site more than half-way up the aneurysm height. Neck-limited: A sidewall aneurysm on the ICA with a neck-limited inflow jet defined as inflow streamlines impacting the aneurysmal wall between the neck and half-way down the aneurysm height. Unvisualized: A sidewall aneurysm on the ICA with unvisualized inflow streamlines defined as no inflow streams into the aneurysm.

The inflow streamline bundles were not visualized during the diastole phase in any of the 57 aneurysms. The inflow jet pattern of each aneurysm was determined by selecting a stable pattern through the systole phase of the cardiac cycle. Three observers (K.F., F.U., and M.N.) independently recorded the inflow jet patterns; disagreements were settled by consensus.

We compared the inflow hemodynamic parameters among the 4 aneurysm groups. The parameters included the maximum inflow velocity, the maximum inflow rate, the inflow velocity ratio (in percentages) (ie, the ratio of the maximum inflow velocity to the maximum flow velocity in the parent artery), and the inflow rate ratio (in percentages) (ie, the ratio of the maximum inflow rate to the maximum flow rate in the parent artery). The maximum inflow velocity and rate were measured on the section plane corresponding to the aneurysmal orifice. The maximum flow velocity and rate in the parent artery were assessed on the section plane in the parent artery just proximal to the aneurysm. All hemodynamic parameters were measured at peak systole by using a function of the Flova II software. Each numeric value was determined as the mean of 3 measurements performed by one of the authors (K.F.).

Statistical analysis was performed with the Mann-Whitney U test for continuous variables and the Fisher exact test for categoric variables. Differences of P < .05 were statistically significant.

Results

Table 1 shows the inflow jet patterns observed at the different thresholds in the 57 aneurysms. The distribution of the patterns was significantly different at the 60% and 90% thresholds (P = .0468). In 16 (28.1%) of the 57 aneurysms, the inflow jet pattern was different at different thresholds (Fig 2). Four of 16 aneurysms classified as group C at the 90% threshold were group D lesions at the 75% threshold; 3 of these 4 aneurysms were sidewall aneurysms. Of the 13 aneurysms classified as group C at the 75% threshold, 5 (38.5%) were group D at the 60% threshold; these 5 were bifurcation aneurysms. Furthermore, 10 of 16 (62.5%) group C and 2 of 14 (14.3%) group D aneurysms at the 90% threshold (P = .0106), 10 of 13 (76.9%) group C and 2 of 18 (11.1%) group D aneurysms at the 75% threshold (P = .0005), and 6 of 8 (75%) group C and 7 of 23 (30.4%) group D aneurysms at the 60% threshold (P = .0429) were bifurcation aneurysms. Because among the 3 thresholds, at 75%, the rate of bifurcation aneurysms was most significantly higher in the concentrated group (group C) than in the diffuse group (group D), we compared the inflow hemodynamic parameters in the 4 groups at the 75% threshold.

View this table:
  • View inline
  • View popup
Table 1:

Inflow jet patterns visualized at the 60%, 75%, and 90% threshold of the maximum velocity in the parent arterya

Fig 2.
  • Download figure
  • Open in new tab
  • Download powerpoint
Fig 2.

Inflow jet patterns on 4D flow MR images determined by observing the inflow streamline bundle with a velocity exceeding visualization thresholds corresponding to 60% (A and D), 75% (B and E), and 90% (C and F) of the maximum velocity in the parent artery. A–C, An aneurysm on the ICA segment branching the posterior communicating artery. D–F, An aneurysm on the paraclinoid segment of the ICA. A and B, A diffuse inflow jet intruding into the aneurysmal dome. The visualization thresholds are 60% (A) and 75% (B). C, A concentrated inflow jet intruding into the aneurysmal dome without dispersion (visualized at the 90% threshold). D, A neck-limited inflow jet visualized at the 60% threshold. E and F, Unvisualized inflow streams—that is, no inflow streams are observed at the 75% (E) and the 90% (F) thresholds.

Table 2 shows the maximum inflow velocity and the maximum inflow rate at the 75% threshold for the different aneurysm groups. The maximum inflow velocity was significantly higher in groups C and D than in group U, and the maximum inflow rate was significantly higher than in groups N and U. There was no statistically significant difference in these values between groups C and D and between groups N and U.

View this table:
  • View inline
  • View popup
Table 2:

Maximum inflow velocity and maximum inflow rate in unruptured aneurysms with different inflow jet patterns visualized at the 75% threshold of the maximum velocity in the parent arterya

In Table 3, we present the inflow velocity ratio and the inflow rate ratio at the 75% threshold for the 4 aneurysm groups. Again, these values were significantly higher in groups C and D than in groups N and U, and there was no statistically significant difference between groups C and D and between groups N and U.

View this table:
  • View inline
  • View popup
Table 3:

Inflow velocity ratio and inflow rate ratio in unruptured aneurysms with different inflow jet patterns visualized at the 75% threshold of the maximum velocity in the parent arterya

Discussion

4D flow MR imaging makes it possible to assess the flow status in human aneurysms.10⇓⇓⇓⇓⇓⇓⇓⇓⇓–20 The hemodynamics (eg, the velocity distribution, inflow streamlines, and flow patterns) determined on 4D flow MR imaging have been validated by computational fluid dynamics studies in human cerebral aneurysms,10,12,14 experimental canine aneurysms,25 and life-size human aneurysm phantoms.22,26,27 The feasibility of visualizing the aneurysmal inflow on 4D flow MR imaging has been confirmed.9,11,14,17,20,21 We used 4D flow MR imaging to evaluate the inflow jet patterns and the inflow hemodynamic parameters in patients with unruptured aneurysms.

At present there is no accepted robust definition of inflow jets. They have been evaluated by visual inspection and characterized by their strongly directed, high-speed flow structure.1,2 Schneiders et al7 and Jansen et al8 defined the inflow jet as the top 25% of the flow magnitude within an aneurysm. However, there may be a considerable difference in the maximum flow magnitude within an aneurysm. In fact, we found that there was a 3.8-fold difference in the mean value of the maximum inflow rate between group C and U lesions (Table 2). According to Szikora et al28 and Castro et al,6 in ruptured aneurysms, the inflow jet tended to enter straight from the parent artery. Their observation suggests that the inflow jet should be defined on the basis of the flow magnitude in the parent artery. We assessed the inflow jets on 4D flow MR imaging by using thresholds based on the maximum flow velocity in the parent artery and classified the aneurysms on the basis of the inflow jet pattern.

Szikora et al28 reported that concentrated inflow jets were observed in most ruptured aneurysms and that all aneurysms with such inflow jets were bifurcation aneurysms; none were sidewall aneurysms. We showed that individual inflow jet patterns reflected the threshold used to visualize the inflow streamlines. Three sidewall aneurysms whose inflow jets were concentrated at the 90% threshold exhibited a diffuse inflow jet at the 75% threshold, while 5 bifurcation aneurysms whose inflow jets were concentrated at the 75% threshold exhibited a diffuse inflow jet at the 60% threshold. The most significant difference in the rate of bifurcation aneurysms between groups C and D was observed at the 75% threshold. However, there is no evidence that the 75% threshold is optimal for evaluating the risk for aneurysmal growth, bleb formation, or rupture. Long-term observation studies are needed to identify the optimal visualization threshold.

Among the aneurysms in our study, those in groups C and D manifested significantly higher values in the inflow hemodynamic parameters than did group N and U lesions (Tables 2 and 3). While there was no statistically significant difference in the maximum inflow velocity, the maximum inflow rates, the inflow velocity ratio, and the inflow rate ratio between groups C and D, concentrated inflow jets may exert a stronger impact force on a small area in the aneurysm wall than diffuse inflow jets. Cebral et al4,5 reported that the inflow jets of ruptured aneurysms tended to be concentrated, while unruptured aneurysms manifested diffuse inflow jets that impacted larger areas. However, it remains unclear at what degree of inflow hemodynamic force aneurysmal rupture is likely. On the other hand, others29,30 have associated aneurysmal rupture with low-flow conditions as seen in our group N and U aneurysms. Our classification of inflow jet patterns and our quantitative estimation of the inflow hemodynamics may be the foundation for further studies investigating risk factors for aneurysmal rupture.

Our study has some limitations. In aneurysms with a low height and a wide neck, the inflow streamline bundle is usually short and wide. This may render it difficult to determine the extent of inflow jet dispersion by visual inspection. To identify risky inflow jet patterns computationally and to avoid subjective judgments, studies to establish numeric values for inflow hemodynamic parameters representing risk factors are needed. 4D flow MR imaging may yield poor-quality images due to motion artifacts attributable to a relatively long acquisition time21 and limited spatial resolution.9⇓⇓⇓⇓–14,17,20,22,25⇓–27 Because flow quantification by using 4D flow MR imaging requires at least 16 isotropic voxels over the vessel lumen area,31 a spatial resolution of 1.0 mm in the isotropic voxel dimensions is needed to evaluate the flow conditions in aneurysms with a diameter of 4.0 mm.22 Although only 1.5T MR imaging scanners are available at our institution, high-resolution MR imaging on greater than 3T instruments may make it possible to evaluate the inflow jets of aneurysms smaller than 4.0 mm.12⇓–14,17,22 While contrast-enhanced 3D cine phase-contrast MR imaging may improve the spatial and temporal resolution, its efficacy for the evaluation of inflow hemodynamics remains to be established. In addition, computational fluid dynamics analysis can be performed on the basis of the accurate vascular geometry with a motion-free acquisition. Additional studies are needed to understand the effects of novel techniques applied to 3D cine phase-contrast MR imaging and to validate the evaluation of small aneurysms on 1.5T scanners by computational fluid dynamics analysis.

Conclusions

The inflow jet pattern may depend on the threshold applied to visualize the inflow streamlines on 4D flow MR images. Because of the significant difference in the rate of bifurcation aneurysms and in the values of inflow hemodynamic parameters, for a classification of the inflow jet patterns on 4D flow MR imaging, the 75% threshold may be optimal within the 3 thresholds corresponding to 60%, 75%, and 90% of the maximum flow velocity in the parent artery.

REFERENCES

  1. 1.↵
    1. Gasteiger R,
    2. Lehmann DJ,
    3. van Pelt R, et al
    . Automatic detection and visualization of qualitative hemodynamic characteristics in cerebral aneurysms. IEEE Trans Vis Comput Graph 2012;18:2178–87 doi:10.1109/TVCG.2012.202 pmid:26357125
    CrossRefPubMed
  2. 2.↵
    1. Neugebauer M,
    2. Gasteiger R,
    3. Janiga G, et al
    . Effective visual exploration of hemodynamics in cerebral aneurysms. In: Proceedings of the Conference of the European Association for Computer Graphics, Geona, Spain; May 6–10, 2013
  3. 3.↵
    1. Cebral JR,
    2. Sheridan M,
    3. Putman CM
    . Hemodynamics and bleb formation in intracranial aneurysms. AJNR Am J Neuroradiol 2010;31:304–10 doi:10.3174/ajnr.A1819 pmid:19797790
    Abstract/FREE Full Text
  4. 4.↵
    1. Cebral JR,
    2. Castro MA,
    3. Burgess JE, et al
    . Characterization of cerebral aneurysms for assessing risk of rupture by using patient-specific computational hemodynamics models. AJNR Am J Neuroradiol 2005;26:2550–59 pmid:16286400
    Abstract/FREE Full Text
  5. 5.↵
    1. Cebral JR,
    2. Mut F,
    3. Weir J, et al
    . Association of hemodynamic characteristics and cerebral aneurysm rupture. AJNR Am J Neuroradiol 2011;32:264–70 doi:10.3174/ajnr.A2274 pmid:21051508
    Abstract/FREE Full Text
  6. 6.↵
    1. Castro MA,
    2. Putman CM,
    3. Sheridan MJ, et al
    . Hemodynamic patterns of anterior communicating artery aneurysms: a possible association with rupture. AJNR Am J Neuroradiol 2009;30:297–302 pmid:19131411
    Abstract/FREE Full Text
  7. 7.↵
    1. Schneiders JJ,
    2. Marquering HA,
    3. Antiga L, et al
    . Intracranial aneurysm neck size overestimation with 3D rotational angiography: the impact on intra-aneurysmal hemodynamics simulated with computational fluid dynamics. AJNR Am J Neuroradiol 2013;34:121–28 doi:10.3174/ajnr.A3179 pmid:22899789
    Abstract/FREE Full Text
  8. 8.↵
    1. Jansen IG,
    2. Schneiders JJ,
    3. Potters WV, et al
    . Generalized versus patient-specific inflow boundary conditions in computational fluid dynamics simulations of cerebral aneurysmal hemodynamics. AJNR Am J Neuroradiol 2014;35:1543–48 doi:10.3174/ajnr.A3901 pmid:24651816
    Abstract/FREE Full Text
  9. 9.↵
    1. Meckel S,
    2. Stalder AF,
    3. Santini F, et al
    . In vivo visualization and analysis of 3-D hemodynamics in cerebral aneurysms with flow-sensitized 4-D MR imaging at 3 T. Neuroradiology 2008;50:473–84 doi:10.1007/s00234-008-0367-9 pmid:18350286
    CrossRefPubMed
  10. 10.↵
    1. Boussel L,
    2. Rayz V,
    3. Martin A, et al
    . Phase-contrast magnetic resonance imaging measurements in intracranial aneurysms in vivo of flow patterns, velocity fields, and wall shear stress: comparisons with computational fluid dynamics. Magn Reson Med 2009;61:409–17 doi:10.1002/mrm.21861 pmid:19161132
    CrossRefPubMed
  11. 11.↵
    1. Hope TA,
    2. Hope MD,
    3. Purcell DD, et al
    . Evaluation of intracranial stenoses and aneurysms with accelerated 4D flow. Magn Reson Imaging 2010;28:41–46 doi:10.1016/j.mri.2009.05.042 pmid:19577400
    CrossRefPubMed
  12. 12.↵
    1. Isoda H,
    2. Ohkura Y,
    3. Kosugi T, et al
    . Comparison of hemodynamics of intracranial aneurysms between MR fluid dynamics using 3D cine phase contrast MRI and MR-based computational fluid dynamics. Neuroradiology 2010;52:913–20 doi:10.1007/s00234-009-0634-4 pmid:19967532
    CrossRefPubMed
  13. 13.↵
    1. Isoda H,
    2. Ohkura Y,
    3. Kosugi T, et al
    . In vivo hemodynamic analysis of intracranial aneurysms obtained by magnetic resonance fluid dynamics (MRFD) based on time-resolved three-dimensional phase-contrast MRI. Neuroradiology 2010;52:921–28 doi:10.1007/s00234-009-0635-3 pmid:20012431
    CrossRefPubMed
  14. 14.↵
    1. Naito T,
    2. Miyachi S,
    3. Matsubara N, et al
    . Magnetic resonance fluid dynamics for intracranial aneurysms: comparison with computed fluid dynamics. Acta Neurochir (Wien) 2012;154:993–1001 doi:10.1007/s00701-012-1305-5 pmid:22392013
    CrossRefPubMed
  15. 15.↵
    1. Kawaguchi T,
    2. Nishimura S,
    3. Kanamori M, et al
    . Distinctive flow pattern of wall shear stress and oscillatory shear index: similarity and dissimilarity in ruptured and unruptured cerebral aneurysm blebs. J Neurosurg 2012;117:774–80 doi:10.3171/2012.7.JNS111991 pmid:22920960
    CrossRefPubMed
  16. 16.↵
    1. Kecskemeti S,
    2. Johnson K,
    3. Wu Y, et al
    . High resolution three-dimensional cine phase contrast MRI of small intracranial aneurysms using a stack of stars k-space trajectory. J Magn Reason Imaging 2012;35:518–27 doi:10.1002/jmri.23501 pmid:22095652
    CrossRefPubMed
  17. 17.↵
    1. van Ooij P,
    2. Schneiders JJ,
    3. Marquering HA, et al
    . 3D cine phase-contrast MRI at 3T in intracranial aneurysms compared with patient-specific computational fluid dynamics. AJNR Am J Neuroradiol 2013;34:1785–91 doi:10.3174/ajnr.A3484 pmid:23598829
    Abstract/FREE Full Text
  18. 18.↵
    1. Schnell S,
    2. Ansari SA,
    3. Vakil P, et al
    . Three-dimensional hemodynamics in intracranial aneurysms: influence of size and morphology. J Magn Reson Imaging 2014;39:120–31 doi:10.1002/jmri.24110 pmid:24151067
    CrossRefPubMed
  19. 19.↵
    1. Berg P,
    2. Stucht D,
    3. Janiga G, et al
    . Cerebral blood flow in a healthy circle of Willis and two intracranial aneurysms: computational fluid dynamics versus four-dimensional phase-contrast magnetic resonance imaging. J Biomech Eng 2014;136 doi:10.1115/1.4026108 pmid:24292415
    CrossRefPubMed
  20. 20.↵
    1. Futami K,
    2. Sano H,
    3. Misaki K, et al
    . Identification of the inflow zone of unruptured cerebral aneurysms: comparison of 4D flow MRI and 3D TOF MRA data. AJNR Am J Neuroradiol 2014;35:1363–70 doi:10.3174/ajnr.A3877 pmid:24610906
    Abstract/FREE Full Text
  21. 21.↵
    1. Futami K,
    2. Sano H,
    3. Kitabayashi T, et al
    . Parent artery curvature influences inflow zone location of unruptured sidewall cerebral aneurysms. AJNR Am J Neuroradiol 2015;36:342–48 70 doi:10.3174/ajnr.A412270 pmid:25234030
    Abstract/FREE Full Text
  22. 22.↵
    1. Hollnagel DI,
    2. Summers PE,
    3. Poulikakos D, et al
    . Comparative velocity investigations in cerebral arteries and aneurysms: 3D phase-contrast MR angiography, laser Doppler velocimetry and computational fluid dynamics. NMR Biomed 2009;22:795–808 doi:10.1002/nbm.1389 pmid:19412933
    CrossRefPubMed
  23. 23.↵
    1. Lorensen WE,
    2. Cline HE
    . Marching cubes: a high resolution 3D surface construction algorithm. ACM Siggraph Computer Graphics 1987;21:163–69 doi:10.1145/37402.37422
    CrossRef
  24. 24.↵
    1. Shimai H,
    2. Yokota H,
    3. Nakamura S, et al
    . Extraction from biological volume data of a region of interest with nonuniform intensity. In: Proceedings of the Society of Photo-Optical Instrumentation Engineers 6051, Optomechatronic Machine Vision, Kauhiko, Sumi, Japan. December 6, 2005; 6051:605115
  25. 25.↵
    1. Jiang J,
    2. Johnson K,
    3. Valen-Sendstad K, et al
    . Flow characteristics in a canine aneurysm model: a comparison of 4D accelerated phase contrast MR measurements and computational fluid dynamics simulations. Med Phys 2011;38:6300–12 doi:10.1118/1.3652917 pmid:22047395
    CrossRefPubMed
  26. 26.↵
    1. van Ooij P,
    2. Guedon A,
    3. Poelma C, et al
    . Complex flow patterns in a real-size intracranial aneurysm phantom: phase contrast MRI compared with particle image velocimetry and computational fluid dynamics. NMR Biomed 2012;25:14–26 doi:10.1002/nbm.1706 pmid:21480417
    CrossRefPubMed
  27. 27.↵
    1. van Ooij P,
    2. Potters WV,
    3. Guédon A, et al
    . Wall shear stress estimated with phase contrast MRI in an in vitro and in vivo intracranial aneurysm. J Magn Reson Imaging 2013;38:876–84 doi:10.1002/jmri.24051 pmid:23417769
    CrossRefPubMed
  28. 28.↵
    1. Szikora I,
    2. Paal G,
    3. Ugron A, et al
    . Impact of aneurysmal geometry on intraaneurysmal flow: a computerized flow simulation study. Neuroradiology 2008;50:411–21 doi:10.1007/s00234-007-0350-x pmid:18180916
    CrossRefPubMed
  29. 29.↵
    1. Xiang J,
    2. Yu J,
    3. Snyder KV, et al
    . Hemodynamic-morphological discriminant models for intracranial aneurysm rupture remain stable with increasing sample size. J Neurointerv Surg 2016;8:104–10 doi:10.1136/neurintsurg-2014-011477 pmid:25488922
    Abstract/FREE Full Text
  30. 30.↵
    1. Yasuda R,
    2. Strother CM,
    3. Taki W, et al
    . Aneurysm volume-to-ostium area ratio: a parameter useful for discriminating the rupture status of intracranial aneurysms. Neurosurgery 2011;68:310–17 doi:10.1227/NEU.0b013e3182010ed0 pmid:21135739
    CrossRefPubMed
  31. 31.↵
    1. Tang C,
    2. Blatter CC,
    3. Paker DL
    . Accuracy of phase-contrast flow measurements in the presence of partial-volume effects. J Magn Reson Imaging 1993;3:377–85 doi:10.1002/jmri.1880030213 pmid:8448400
    CrossRefPubMed
  • Received August 7, 2015.
  • Accepted after revision December 16, 2015.
  • © 2016 by American Journal of Neuroradiology
View Abstract
PreviousNext
Back to top

In this issue

American Journal of Neuroradiology: 37 (7)
American Journal of Neuroradiology
Vol. 37, Issue 7
1 Jul 2016
  • Table of Contents
  • Index by author
  • Complete Issue (PDF)
Advertisement
Print
Download PDF
Email Article

Thank you for your interest in spreading the word on American Journal of Neuroradiology.

NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

Enter multiple addresses on separate lines or separate them with commas.
Inflow Jet Patterns of Unruptured Cerebral Aneurysms Based on the Flow Velocity in the Parent Artery: Evaluation Using 4D Flow MRI
(Your Name) has sent you a message from American Journal of Neuroradiology
(Your Name) thought you would like to see the American Journal of Neuroradiology web site.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Citation Tools
Inflow Jet Patterns of Unruptured Cerebral Aneurysms Based on the Flow Velocity in the Parent Artery: Evaluation Using 4D Flow MRI
K. Futami, T. Kitabayashi, H. Sano, K. Misaki, N. Uchiyama, F. Ueda, M. Nakada
American Journal of Neuroradiology Jul 2016, 37 (7) 1318-1323; DOI: 10.3174/ajnr.A4704

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Share
Inflow Jet Patterns of Unruptured Cerebral Aneurysms Based on the Flow Velocity in the Parent Artery: Evaluation Using 4D Flow MRI
K. Futami, T. Kitabayashi, H. Sano, K. Misaki, N. Uchiyama, F. Ueda, M. Nakada
American Journal of Neuroradiology Jul 2016, 37 (7) 1318-1323; DOI: 10.3174/ajnr.A4704
del.icio.us logo Digg logo Reddit logo Twitter logo Facebook logo Google logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Google Plus One
Purchase

Jump to section

  • Article
    • Abstract
    • Materials and Methods
    • Results
    • Discussion
    • Conclusions
    • REFERENCES
  • Figures & Data
  • Info & Metrics
  • References
  • PDF

Related Articles

  • No related articles found.
  • PubMed
  • Google Scholar

Cited By...

  • Associations between haemodynamics and wall enhancement of intracranial aneurysm
  • Large Neck and Strong Ostium Inflow as the Potential Causes for Delayed Occlusion of Unruptured Sidewall Intracranial Aneurysms Treated by Flow Diverter
  • Identification of Vortex Cores in Cerebral Aneurysms on 4D Flow MRI
  • Crossref
  • Google Scholar

This article has not yet been cited by articles in journals that are participating in Crossref Cited-by Linking.

More in this TOC Section

  • ADC Level is Related to DWI Reversal in Patients Undergoing Mechanical Thrombectomy: A Retrospective Cohort Study
  • Angiographically Occult Subarachnoid Hemorrhage: Yield of Repeat Angiography, Influence of Initial CT Bleed Pattern, and Sources of Diagnostic Error in 242 Consecutive Patients
  • Rabbit Elastase Aneurysm Model Mimics the Recurrence Rate of Human Intracranial Aneurysms following Platinum Coil Embolization
Show more INTERVENTIONAL

Similar Articles

Advertisement

News and Updates

  • Lucien Levy Best Research Article Award
  • Thanks to our 2021 Distinguished Reviewers
  • Press Releases

Resources

  • Evidence-Based Medicine Level Guide
  • How to Participate in a Tweet Chat
  • AJNR Podcast Archive
  • Ideas for Publicizing Your Research
  • Librarian Resources
  • Terms and Conditions

Opportunities

  • Share Your Art in Perspectives
  • Get Peer Review Credit from Publons
  • Moderate a Tweet Chat

American Society of Neuroradiology

  • Neurographics
  • ASNR Annual Meeting
  • Fellowship Portal
  • Position Statements

© 2022 by the American Society of Neuroradiology | Print ISSN: 0195-6108 Online ISSN: 1936-959X

Powered by HighWire