Cardiac Cycle-Related Volume Change in UnrupturedCerebral Aneurysms

A Detailed Volume Quantification Study Using 4-DimensionalCT Angiography

Junko Kuroda, MD; Manabu Kinoshita, MD, PhD; Hisashi Tanaka, MD, PhD; Takeo Nishida, MD;Hajime Nakamura, MD, PhD; Yoshiyuki Watanabe, MD, PhD; Noriyuki Tomiyama, MD, PhD;

Toshiyuki Fujinaka, MD, PhD; Toshiki Yoshimine, MD, PhD

Background and Purpose—The hemodynamic factors of aneurysms were recently evaluated using computational fluiddynamics in a static vessel model in an effort to understand the mechanisms of initiation and rupture of aneurysms.However, few reports have evaluated the dynamic wall motion of aneurysms due to the cardiac cycle. The objective ofthis study was to quantify cardiac cycle-related volume changes in aneurysms using 4-dimensional CT angiography.

Methods—Four-dimensional CT angiography was performed in 18 patients. Image data of 1 cardiac cycle were dividedinto 10 phases and the volume of the aneurysm was then quantified in each phase. These data were also compared withintracranial vessels of normal appearance.

Results—The observed cardiac cycle-related volume changes were in good agreement with the sizes of the aneurysms andnormal vessels. The cardiac cycle-related volume changes of the intracranial aneurysms and intracranial normal arterieswere 5.40%�4.17% and 4.20�2.04%, respectively, but these did not differ statistically (P�0.12).

Conclusions—We successfully quantified the volume change in intracranial aneurysms and intracranial normal arteries inhuman subjects. The data may indicate that cardiac cycle-related volume changes do not differ between unrupturedaneurysms and normal intracranial arteries, suggesting that the global integrity of an unruptured aneurysmal wall is notdifferent from that of normal intracranial arteries. (Stroke. 2012;43:61-66.)

Key Words: 4DCTA � intracranial aneurysm � quantification of volume change

Incidental discovery of unruptured cerebral aneurysms isnow common, partially due to the prevalence of MR

angiography for screening intracranial abnormalities in dailyclinical settings. The rate of rupture of these aneurysms isreported to be 0.3% to 4.0% per year1–7 and appropriatemanagement is required. Risk assessment of future ruptureleading to subarachnoid hemorrhage is important in thedecision to intervene with these unruptured aneurysms. Todate, the reported risk factors for rupture of cerebral aneu-rysms are size, location, hypertension, and history ofsmoking.5,7–9

To further evaluate the risks and theoretical foundations ofrupture of unruptured aneurysms, the hemodynamic factors ofaneurysms were recently evaluated in detail using computa-tional fluid dynamics and electrocardiographic gated CTangiography. In addition, studies have also examined the useof 4-dimensional CT angiography (4DCTA) to detect aneu-rysm blebs to predict the rupture point.10–12

However, most previous reports have focused only on thestatic morphological characteristics of the aneurysm, and fewhave attempted to evaluate the dynamic shape or volumechanges of an aneurysm caused by arterial pulsed pressurecaused by the heartbeat. The aneurysm is stretched in eachcardiac cycle, and understanding the magnitude of thischange is thus crucial to understand the hemodynamicsinvolved in cerebral aneurysms. Thus, we quantified thevolume changes caused by the cardiac cycle in unrupturedcerebral aneurysms using 320 multidetector 4DCTA.

Materials and MethodsClinical MaterialsTwenty-two unruptured cerebral aneurysms from 18 patients wereanalyzed by 4DCTA as preoperative assessment. Five aneurysmswere located at the internal carotid artery, 8 at the middle cerebralartery, 3 at the anterior communicating artery, 5 at the anteriorcerebral artery, and 1 at the basilar artery. The local ethics committeeapproved the use of the clinical data for research and waived the

Received May 25, 2011; final revision received July 26, 2011; accepted August 10, 2011.From the Departments of Neurosurgery (J.K., M.K., T.N., H.N., T.F., T.Y.) and Radiology (H.T., Y.W., N.T.), Osaka University Graduate School of

Medicine, Osaka, Japan.Correspondence to Manabu Kinoshita, MD, PhD, Department of Neurosurgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita,

Osaka 565-0871, Japan. E-mail m-kinoshita@nsurg.med.osaka-u.ac.jp© 2011 American Heart Association, Inc.

Stroke is available at http://stroke.ahajournals.org DOI: 10.1161/STROKEAHA.111.626846

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requirement for written informed consent from patients. Detailedpatient data are listed in Table 1.

4DCTA AcquisitionElectrocardiography-triggered CT angiography was performed on a320-detector CT system (Aquilion ONE; Toshiba, Nasu, Japan)using the following parameters: 120-kV tube voltage, 270-mA tubecurrent, 350-ms gantry rotation time, 140-mm range, and 1 heartbeat.Contrast medium (Optiray 320 mgI/mL; Coviden Japan, Tokyo,Japan) was injected at a 5-mL/s infusion rate. After the test injectionwith 15 mL of contrast medium, the actual scanning was started atthe appropriate time according to the test injection. For the actualscanning, 50 mL of contrast medium was used. Images for this studywere reconstructed using a kernel optimized for intracranial vesselimaging (window center, each 10% of the R-R interval; imagematrix, 512�512; pixel interval 0.25 mm or 0.5 mm). Thus, 10 CTvolume data sets were created for each patient. All of the CT datasets were transferred to an offline workstation and further analyzedby an in-house program developed using Matlab (MathWorks,Natick, MA) as detailed subsequently (Figure 1A).

Analysis of Cardiac Cycle-Related VolumeChanges in Cerebral Aneurysms and NormalCerebral VesselsFirst, the cerebral arteries were identified in the raw CT data byadjusting the window and level values from 110 to 890. For deletionof brain tissues and most of the bone structures at the same time asretaining the signals from the contrast medium, window and levelvalues �110 and �890 were substituted for 0. Next, a value of 1 wassubstituted for the voxels with vessels or bones, and 0 was substi-tuted for those without. As a result, the original row CT data of eachphase was converted into a 512�512�640 or 512�512�570 matrix

(Figure 1B). Next, to evaluate the volume change in an aneurysmcaused by the heartbeat, the dome of the aneurysm, not including theparent artery, was selected as 3-dimensional voxels of interest(Figures 1C and 2A). The volume of the aneurysm was thenestimated in each phase of the cardiac cycle. At the same time, thevolumes of normal cerebral arteries were estimated using the sametechnique for comparison to the aneurysms at the following loca-tions: bifurcation of the middle cerebral artery, the tip of the internalcarotid artery, and the tip of the basilar artery. As shown in Figure1C, the terminal areas of internal carotid artery, middle cerebralartery, and basilar artery, not including the parent artery and vesseltrunks, were selected as voxels of interest. Vessels affected by theaneurysm were excluded from analysis. The presented data wereobtained by voxel of interest placed by a single operator (J.K.).Interobserver variation was confirmed by analyzing randomly se-lected 5 aneurysms and 15 normal vessels by an independentoperator (M.K.). Interobserver discrepancy was measured to be11.9�17.6 mm3 in aneurysm and 1.54�3.9 mm3 in normal vessels,which was considered acceptable for further analysis.

Artifact MeasurementBecause a rotating x-ray beam can induce artifacts that may impactvolume measurement,13,14 we measured the volume change in asyringe filled with normal saline as a phantom under the sameconditions. We observed a 0.248% volume change during the timeequivalent to 1 cardiac cycle (1 second). Therefore, a volume changeof �0.248% was considered to indicate an insignificant artifact.

Statistical AnalysisStatistical analysis was performed using Student t test and JMPsoftware (SAS, Cary, NC). One-way analysis of variance wasused for 3-group comparison. P�0.05 was considered statisticallysignificant.

ResultsThe results are summarized in Table 2. The volume changesin an aneurysm and a normal cerebral artery at each phaseduring 1 cardiac cycle are shown in Figure 2B. Both casesshowed waveforms containing 2 peaks resembling an arterialpulse wave.15

To quantify the volume change during 1 cardiac cycle, thefollowing parameters were defined. Expansion volume (Ex.volume) was defined as the difference between the maximumand minimum volume of the aneurysm or arterial vesselwithin the voxel of interest during 1 cardiac cycle. Expansionrate (Ex. rate) was defined as Ex. volume divided byminimum volume, indicating the magnitude of expansion ofthe aneurysm or the normal arterial vessel.

First we investigated volume changes in normal intracra-nial arteries due to the cardiac cycle. The minimum volume ateach arterial location did not differ (Figure 3A). Moreover,the Ex. rates did not differ significantly between differentlocations for normal arterial vessels (Figure 3B), confirmingour previous findings.16

Next, unruptured cerebral aneurysms were analyzed. TheEx. volume of an aneurysm and normal arterial vessel wereplotted as a function of minimum volume in Figure 4A, whichshows that Ex. volume is in good agreement with the volumeof both the aneurysm and the normal arterial vessel itself(R�0.89 and 0.41, respectively). Bifurcation aneurysms,dilating coaxially against the blood flow of parent arteries,were 13, and side-wall aneurysms, dilating parallel to theblood flow of parent arteries, were 9 among 22 aneurysms.Ex. volume of bifurcation aneurysms and side-wall aneu-

Table 1. Patient Profiles

No. Age, Y Sex Location Size, mm

1 53 M MCA 5.21�7.83�6.05

2 66 F ACOM 3.96�4.64�4.34

3 55 F ICA 10.71�9.43�7.98

4 70 M MCA 16.66�16.34�17.20

5 50 F ICA 3.23�3.75�3.5

6 66 F ACA 7.23�7.60�7.41

BA 14.26�14.01�13.85

7 69 F ACA 3.36�3.35�4.04

8 67 F ACA 16.10�13.58�15.61

9 61 F ICA 5.96�4.05�2.83

10 76 F MCA 12.46�16.50�17.62

11 50 F ICA 5.19�5.77�5.21

12 64 F ACOM 4.25�4.39�4.45

13 63 F ACOM 5.93�5.97�6.55

14 68 F MCA 3.97�3.15�4.41

15 49 F ACA 1.73�2.11�2.72

MCA 7.75�9.65�6.45

MCA 6.33�3.72�4.48

MCA 3.81�3.25�3.41

16 74 F MCA 5.49�6.58�5.30

17 62 F ACA 2.77�3.77�4.08

18 62 M ICA 3.39�3.66�3.88

M indicates male; F, female, MCA, middle cerebral artery; ACOM, anteriorcommunicating artery; ICA, internal carotid artery; ACA, anterior cerebral artery;BA, basilar artery.

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rysms were 30.5�75.2 mm3 and 24.0�18.6 mm3, respec-tively. There was no significant difference between these 2groups (P�0.81). Ex. rate of bifurcation aneurysms andside-wall aneurysms were 5.6%�3.7% and 5.1%�4.5%,respectively, and also not significantly different (P�0.76).

An attempt was made to numerically compare the extent ofexpansion between aneurysms and normal arterial vessels. Asshown in Table 2, Ex. volume of aneurysms and normalvessels were 27.87�60.53 mm3 and 3.10�1.81 mm3, respec-tively. It was significantly different between aneurysms andnormal arterial vessels (P�0.003). However, the mean Ex.rates of aneurysms and normal arteries were 5.40%�4.07%and 4.20%�2.51%, respectively, and were not significantlydifferent (P�0.12; Table 2; Figure 4B). Overall, these resultsindicate that cardiac cycle-related volume changes do notdiffer between unruptured aneurysms and normal intracranialarteries.

DiscussionElucidating the mechanism(s) involved in the initiation,enlargement, and rupture of cerebral aneurysms is crucial forunderstanding the nature of unruptured cerebral aneurysms.Although the rupture rate of unruptured cerebral aneurysms isreported to be quite low,1–7 rupture results in subarachnoidhemorrhage with potentially devastating consequences. Inaddition to etiologic surveys,2,7–9,17 computational simulationof the flow at and around an aneurysm has generatedextensive interest as a means to discovering the underlyinghemodynamic mechanism(s) that cause physical stress to theaneurysmal wall, possibly resulting in aneurysmal rup-ture.18–20 Moreover, several studies have evaluated the extentof wall motion of cerebral aneurysms and normal arteries asrelated to the cardiac cycle.10–12,14,16,21–23

After the development of 4DCTA, some studies have per-formed radiological visualization of the cardiac cycle-related

Dynamic 4D-CTA

Time Phase Images

0% 50% 90%

Aneurysm and

normal artery Extraction

Time Phase Images Time Phase Vessel Images

B

C

Aneurysm Normal Vessels

A

Figure 1. Schematic illustrations of reconstructed4DCTA data. A, The window center of the time-phase image is set at each 10% of the R-R inter-val and the 4DCTA image of 1 cardiac cycle wasreconstructed into 10 phase images. B, Timephase images were digitalized for aneurysm andnormal arterial vessel extraction. C, Diagrams forVOI selection are presented for aneurysms andnormal vessels. 4DCTA indicates 4-dimensionalCT angiography; VOI, voxel of interest.

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wall motion of aneurysmal walls using 4DCTA.10–12,14,16,22,23

However, in most of these studies, no quantification of themotion was performed. We previously reported for the firsttime that quantification of cardiac cycle-related vessel vol-ume change and vessel motion is indeed possible using4DCTA,16 a finding confirmed by others.14 In the presentreport, we attempted to quantify cardiac cycle-related volumechange in normal intracranial arteries and unrupturedaneurysms.

Because volume change directly correlates with the extentof wall motion of the object of interest, we speculated that thecardiac cycle-related volume change assessment would ap-proximate the wall motion assessment. As shown in Figure4B, we did not observe a difference in cardiac cycle-relatedvolume changes rates between unruptured cerebral aneu-rysms and normal intracranial arteries. On the other hand,Oubel et al reported that the extent of wall motion of rupturedaneurysms has a higher value than that of unruptured aneu-

Figure 2. VOI selection and volume change quantification of case No. 6, a basilar artery aneurysm. A, The VOI for aneurysm analysis isillustrated. The aneurysmal dome, not including the parent artery, was identified by axial, sagittal, and coronal images and chosen asthe VOI for analysis. B, Volume changes in the aneurysm (basilar artery aneurysm) and the normal artery (the tip of the left ICA) during1 cardiac cycle are presented (Patient 6). Both waveforms resemble an arterial pulse wave. Most of the cases presented a similar wavepattern, suggesting that volume changes in both aneurysms and normal arterial vessels are governed by the cardiac cycle. VOI indi-cates voxel of interest; ICA, internal carotid artery.

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rysms, an estimation made using digital subtraction angiog-raphy.22 However, the values used for comparison in theirreport did not take into consideration the volume of theaneurysm itself. As can be seen in Figure 4A, the volume ofboth the aneurysm and normal arterial vessel strictly governsthe amount of cardiac cycle-related volume change. Thisobservation suggests the need to compensate the cardiaccycle-related volume change or wall motion by the actualvolume of the object of interest. The observed slight differ-ence in the correlation of the volume and the amount ofcardiac cycle-related volume change between normal vesselsand aneurysm should be mentioned (Figure 4A). One possibleexplanation could be that large aneurysms were compressedby the surrounding tissue such as the brain, leading to arelatively smaller amount of cardiac cycle-related volumechange considering its minimum volume.

It should also be noted that this is the first study attemptingto accurately quantify cardiac cycle-related volume changesin cerebral aneurysms or normal cerebral arteries. Meyers etal previously reported the quantification of aneurysm volumechanges with phase-contrast MR angiography.21 In theirreport, the ruptured and unruptured intracranial aneurysmsdemonstrated a 51%�10% and 17.6%�8.9% increase involume during 1 cardiac cycle, which is markedly differentfrom the present result (5.40%�4.07%). One of the majorreasons for this difference is that they estimated the volume ofthe aneurysm using 2-dimensional images assuming a spher-ical shape for the aneurysm, although an aneurysm has anirregular shape in situ. Another reason for the discrepancybetween the 2 findings is the different modalities used in the2 studies. In phase-contrast MR angiography, the complexpulsatile flow into the aneurysm causes absence of signal,possibly resulting in overestimation.

Our investigation failing to find a difference in cardiaccycle-related volume changes between aneurysms and normalarterial vessels may suggest that the global integrity of the

aneurysmal wall is not different from that of normal vessels.If aneurysmal walls are compromised by stretching forces,then the expansion rate would be larger than that of normalvessels. However, the presented analysis was unable to reflectmicrolevel wall motion differences, and thus visualization orquantification of aneurysmal wall motion at a more detailedlevel is required to identify locations at risk of futureaneurysmal rupture. For instance, it is necessary to conductlong-term follow-ups for those aneurysms presenting a highEx. rate in Figure 4B to elucidate if high Ex. rate wouldindicate high risk for future rupture. Moreover, furtheranalysis of ruptured aneurysms is required to examine thecomprehensiveness of our findings. Finally, incorporation ofthe cardiac cycle-related volume changes in aneurysms into

Table 2. Expansion Volume and Rate

Aneurysm Normal Vessel P

No. of lesions analyzed 22 56

Expansionvolume, mm3

27.87�60.53 3.10�1.81 0.003

Expansion rate, % 5.40�4.07 4.20�2.54 0.12

Data are presented as mean�standard deviation.

Figure 3. Minimum volume and expansion rate ofnormal arterial vessels at each anatomic location.A, The minimum volumes of normal arterial vesselsare grouped according to anatomic location. Therewere no statistically significant differences betweenthe groups (1-way ANOVA, P�0.05). B, Theexpansion rates of normal arterial vessels aregrouped according to anatomic location. Therewere no statistically significant differences betweenthe groups (1-way ANOVA, P�0.05). ANOVA indi-cates analysis of variance; ICA, internal carotidartery; MCA, middle cerebral artery; BA, basilarartery.

Figure 4. Relationship between the expansion volume and theminimum volume of the cerebral aneurysms and the normalcerebral arteries. A, The R value of the aneurysms and normalarteries were 0.89 and 0.41, respectively. B, Expansion rates ofaneurysms and normal vessels are presented. Data representmean�SD. The difference was not statistically significant.

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computational fluid dynamics is necessary to understand theimpact of cardiac cycle-related wall motion in the physics ofthe fluid dynamics of aneurysms.

Sources of FundingThis investigation was supported by the Osaka Cancer ResearchFoundation, the Konica Minolta Imaging Science Foundation, theOsaka Cancer Researcher Training Fund, the Takeda Science Foun-dation, the Sagawa Foundation for Promotion of Cancer Research,and a Grant-in-Aid for Scientific Research from the Ministry ofEducation, Science and Culture of Japan.

DisclosuresNone.

References1. Unruptured intracranial aneurysms—risk of rupture and risks of surgical

intervention. International study of unruptured intracranial aneurysmsinvestigators. N Engl J Med. 1998;339:1725–1733.

2. Juvela S, Porras M, Poussa K. Natural history of unruptured intracranialaneurysms: probability and risk factors for aneurysm rupture. NeurosurgFocus. 2000;8:Preview 1.

3. Morita A, Kimura T, Shojima M, Sameshima T, Nishihara T. Unrupturedintracranial aneurysms: current perspectives on the origin and naturalcourse, and quest for standards in the management strategy. Neurol MedChir (Tokyo). 50:777–787.

4. Rinkel GJ, Djibuti M, Algra A, van Gijn J. Prevalence and risk of ruptureof intracranial aneurysms: a systematic review. Stroke. 1998;29:251–256.

5. Tsutsumi K, Ueki K, Morita A, Kirino T. Risk of rupture from incidentalcerebral aneurysms. J Neurosurg. 2000;93:550–553.

6. Wermer MJ, van der Schaaf IC, Algra A, Rinkel GJ. Risk of rupture ofunruptured intracranial aneurysms in relation to patient and aneurysmcharacteristics: an updated meta-analysis. Stroke. 2007;38:1404–1410.

7. Wiebers DO, Whisnant JP, Huston J III, Meissner I, Brown RD Jr,Piepgras DG, et al. Unruptured intracranial aneurysms: natural history,clinical outcome, and risks of surgical and endovascular treatment.Lancet. 2003;362:103–110.

8. Juvela S, Poussa K, Porras M. Factors affecting formation and growth ofintracranial aneurysms: a long-term follow-up study. Stroke. 2001;32:485–491.

9. Yonekura M. Small unruptured aneurysm verification (SUAVe Study,Japan)—interim report. Neurol Med Chir (Tokyo). 2004;44:213–214.

10. Hayakawa M, Katada K, Anno H, Imizu S, Hayashi J, Irie K, et al. CTangiography with electrocardiographically gated reconstruction for visu-

alizing pulsation of intracranial aneurysms: identification of aneurysmalprotuberance presumably associated with wall thinning. AJNR Am JNeuroradiol. 2005;26:1366–1369.

11. Ishida F, Ogawa H, Simizu T, Kojima T, Taki W. Visualizing thedynamics of cerebral aneurysms with four-dimensional computed tomo-graphic angiography. Neurosurgery. 2005;57:460 – 471; discussion460–471.

12. Kato Y, Hayakawa M, Sano H, Sunil MV, Imizu S, Yoneda M, et al.Prediction of impending rupture in aneurysms using 4D-CTA: histopatho-logical verification of a real-time minimally invasive tool in unrupturedaneurysms. Minim Invasive Neurosurg. 2004;47:131–135.

13. Matsumoto M, Sasaki T, Suzuki K, Sakuma J, Endo Y, Kodama N.Visualizing the dynamics of cerebral aneurysms with four-dimensionalcomputed tomographic angiography. Neurosurgery. 2006;58:E1003;author reply E1003.

14. Umeda Y, Ishida F, Hamada K, Fukazawa K, Miura Y, Toma N, et al.Novel dynamic four-dimensional CT angiography revealing 2-typemotions of cerebral arteries. Stroke. 42:815–818.

15. O’Rourke MF, Pauca A, Jiang XJ. Pulse wave analysis. Br J ClinPharmacol. 2001;51:507–522.

16. Nishida T, Kinoshita M, Tanaka H, Fujinaka T, Yoshimine T. Quantifi-cation of cerebral artery motion during the cardiac cycle. AJNR Am JNeuroradiol. Epub ahead of print February 24, 2011. DOI: 10.3174/ajnr.A2354.

17. Morita A, Fujiwara S, Hashi K, Ohtsu H, Kirino T. Risk of ruptureassociated with intact cerebral aneurysms in the Japanese population: asystematic review of the literature from Japan. J Neurosurg. 2005;102:601–606.

18. Sforza DM, Putman CM, Cebral JR. Hemodynamics of cerebral aneu-rysms. Annu Rev Fluid Mech. 2009;41:91–107.

19. Shojima M, Oshima M, Takagi K, Torii R, Hayakawa M, Katada K, et al.Magnitude and role of wall shear stress on cerebral aneurysm: computa-tional fluid dynamic study of 20 middle cerebral artery aneurysms.Stroke. 2004;35:2500–2505.

20. Shojima M, Oshima M, Takagi K, Torii R, Nagata K, Shirouzu I, et al.Role of the bloodstream impacting force and the local pressure elevationin the rupture of cerebral aneurysms. Stroke. 2005;36:1933–1938.

21. Meyer FB, Huston J III, Riederer SS. Pulsatile increases in aneurysm sizedetermined by cine phase-contrast MR angiography. J Neurosurg. 1993;78:879–883.

22. Oubel E, Cebral JR, De Craene M, Blanc R, Blasco J, Macho J, et al. Wallmotion estimation in intracranial aneurysms. Physiol Meas. 2010;31:1119–1135.

23. Yaghmai V, Rohany M, Shaibani A, Huber M, Soud H, Russell EJ, etal. Pulsatility imaging of saccular aneurysm model by 64-slice CTwith dynamic multiscan technique. J Vasc Interv Radiol. 2007;18:785–788.

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Yoshiyuki Watanabe, Noriyuki Tomiyama, Toshiyuki Fujinaka and Toshiki YoshimineJunko Kuroda, Manabu Kinoshita, Hisashi Tanaka, Takeo Nishida, Hajime Nakamura,

Volume Quantification Study Using 4-Dimensional CT AngiographyCardiac Cycle-Related Volume Change in Unruptured Cerebral Aneurysms: A Detailed

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Abstract 27

心周期に関連した未破裂脳動脈瘤の容積変化 — 四次元 CT 血管造影を用いた詳細な容積定量化研究Cardiac Cycle-Related Volume Change in Unruptured Cerebral Aneurysms ― A Detailed Volume Quantification Study Using 4-Dimensional CT Angiography

Junko Kuroda, MD1; Manabu Kinoshita, MD, PhD1; Hisashi Tanaka, MD, PhD2; Takeo Nishida, MD1; Hajime Nakamura, MD, PhD1; Yoshiyuki Watanabe, MD, PhD2; Noriyuki Tomiyama, MD, PhD2; Toshiyuki Fujinaka, MD, PhD1; Toshiki Yoshimine, MD, PhD1

1 Departments of Neurosurgery and 2 Radiology, Osaka University Graduate School of Medicine, Osaka, Japan.

背景および目的：動脈瘤の発生および破裂の機序を理解する努力のなかで，静的血管モデルで数値流体力学を用いた動脈瘤の血行力学的要因の評価が最近行われている。しかし，心周期に起因する動脈瘤の動的壁運動を評価した報告はほとんどない。本研究の目的は，四次元 CT 血管造影法を用いて心周期に関連した動脈瘤の容積変化を定量化することである。方法：18 例の患者を対象として四次元 CT 血管造影を行った。1 心周期の画像データを 10 相に分割し，各相の動脈瘤の容積を定量化した。また，これらのデータを正常な外観をもつ頭蓋内血管と比較した。

結果：観察された心周期に関連した容積変化は，動脈瘤および正常血管のサイズとよく一致していた。頭蓋内動脈瘤および頭蓋内正常動脈の心周期に関連した容積変化はそれぞれ 5.40 ± 4.17％および 4.20 ± 2.04％であったが，これらの間に統計学的有意差は認められなかった（p ＝ 0.12）。結論：ヒト被験者における頭蓋内動脈瘤および頭蓋内正常動脈の容積変化の定量化に成功した。データは，未破裂の動脈瘤と正常な頭蓋内動脈の間で心周期に関連した容積変化に差はないことを示していると思われ，未破裂動脈瘤壁の全体的な健全性は正常な頭蓋内動脈と差がないことが示唆される。

Stroke 2012; 43: 61-66

Abstract

図 2脳底動脈瘤（症例 No. 6）の VOI 選択および容積変化の定量化。A，動脈瘤解析の VOI を示す。動脈瘤ドーム（親動脈は含まない）を軸位断像，矢状断像，および冠状断像により同定し，解析の VOI として選択した。AN：動脈瘤，BA：脳底動脈，PCA：後大脳動脈，SCA：上大脳動脈，VOI：関心ボクセル，ICA：内頸動脈。

A

軸位断

BA BAAN

AN AN

SCA

PCA

セグメンテーション前 動脈瘤のセグメンテーション

矢状断 冠状断

（Stroke 誌の図を一部省略して記載）

stroke7-1.indb 27 12.6.22 1:56:05 PM