This Article Abstract Full Text (PDF) Data Supplement All Versions of this Article: 106/3/296    most recent 01.CIR.0000025629.85631.1Ev1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Kim, W. Y. Articles by Botnar, R. M. Search for Related Content PubMed PubMed Citation Articles by Kim, W. Y. Articles by Botnar, R. M. Related Collections Imaging CT and MRI Coronary circulation

(Circulation. 2002;106:296.)
© 2002 American Heart Association, Inc.

Brief Rapid Communications

Three-Dimensional Black-Blood Cardiac Magnetic Resonance Coronary Vessel Wall Imaging Detects Positive Arterial Remodeling in Patients With Nonsignificant Coronary Artery Disease

W. Yong Kim, MD, PhD; Matthias Stuber, PhD; Peter Börnert, PhD; Kraig V. Kissinger, BS, RT; Warren J. Manning, MD; René M. Botnar, PhD

From the Department of Medicine (W.Y.K., M.S., W.J.M, R.M.B.), Cardiovascular Division, and the Department of Radiology (W.J.M.), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Mass; The MR-Center, Department of Cardiology (W.Y.K.) and Institute of Experimental Clinical Research, Aarhus University Hospital, Skejby Sygehus, Denmark; Philips Medical Systems (M.S., R.M.B.), Best, the Netherlands; and Philips Research Laboratories (P.B.), Hamburg, Germany.

Correspondence to René M. Botnar, PhD, Beth Israel Deaconess Medical Center, Cardiovascular Division, Cardiac MR Center 330 Brookline Ave, Boston, MA, 02215. E-mail rbotnar{at}caregroup.harvard.edu

	Abstract

Top Abstract Introduction Methods Results Discussion References

 
Background— Direct noninvasive visualization of the coronary vessel wall may enhance risk stratification by quantifying subclinical coronary atherosclerotic plaque burden. We sought to evaluate high-resolution black-blood 3D cardiovascular magnetic resonance (CMR) imaging for in vivo visualization of the proximal coronary artery vessel wall.

Methods and Results— Twelve adult subjects, including 6 clinically healthy subjects and 6 patients with nonsignificant coronary artery disease (10% to 50% x-ray angiographic diameter reduction) were studied with the use of a commercial 1.5 Tesla CMR scanner. Free-breathing 3D coronary vessel wall imaging was performed along the major axis of the right coronary artery with isotropic spatial resolution (1.0x1.0x1.0 mm³) with the use of a black-blood spiral image acquisition. The proximal vessel wall thickness and luminal diameter were objectively determined with an automated edge detection tool. The 3D CMR vessel wall scans allowed for visualization of the contiguous proximal right coronary artery in all subjects. Both mean vessel wall thickness (1.7±0.3 versus 1.0±0.2 mm) and wall area (25.4±6.9 versus 11.5±5.2 mm²) were significantly increased in the patients compared with the healthy subjects (both P<0.01). The lumen diameter (3.6±0.7 versus 3.4±0.5 mm, P=0.47) and lumen area (8.9±3.4 versus 7.9±3.5 mm², P=0.47) were similar in both groups.

Conclusions— Free-breathing 3D black-blood coronary CMR with isotropic resolution identified an increased coronary vessel wall thickness with preservation of lumen size in patients with nonsignificant coronary artery disease, consistent with a "Glagov-type" outward arterial remodeling. This novel approach has the potential to quantify subclinical disease.

Key Words: atherosclerosis • plaque • vessels • magnetic resonance imaging

	Introduction

Top Abstract Introduction Methods Results Discussion References

 
Coronary magnetic resonance angiography (MRA) allows for the noninvasive assessment of significant coronary artery luminal stenosis.¹ However, assessment of coronary lumen integrity is of limited value for the detection of subclinical coronary artery disease (CAD) because at the early stages of atherosclerosis, the coronary artery lumen is usually preserved by outward (positive) arterial remodeling, known as the Glagov effect.² It is of clinical importance to recognize subclinical CAD because acute coronary syndromes frequently result from rupture of an atherosclerotic plaque in an area of only mild-to-moderate luminal narrowing.^3,4

We have recently implemented a black-blood three-dimensional (3D) cardiovascular magnetic resonance (CMR) sequence with isotropic image resolution to enable vessel wall imaging along the major axis of the proximal coronary arteries.⁵ In the present study, we sought to determine whether this novel approach can detect outward arterial remodeling (by means of an increased coronary wall thickness) in patients with subclinical CAD.

	Methods

Top Abstract Introduction Methods Results Discussion References

 
Subjects
The study population included 6 clinically healthy adult subjects without known cardiac disease (2 males and 4 females; aged 33±12 years, range 25 to 57 years) and 6 patients (4 males and 2 females; aged 67±10 years, range 54 to 79 years) with nonsignificant stenoses (10% to 50% diameter reduction) by x-ray coronary angiography. One patient had been referred for x-ray angiography before heart valve replacement, whereas the others were referred for evaluation of suspected CAD. Coronary MRA and CMR vessel wall imaging of the right coronary artery (RCA) were performed in all subjects. All subjects were in sinus rhythm, without contraindications to CMR exams, and provided written informed consent.

CMR Imaging Procedure
The CMR examination was performed on a commercial 1.5 Tesla system (Gyroscan ACS-NT 15, Philips Medical Systems) equipped with PowerTrak 6000 gradients (23 mT/m, 219 µs rise time). All subjects were examined in the supine position with the use of a commercial 5-element cardiac synergy receiver coil. All coronary scans were performed with cardiac synchronization during free breathing with the use of a navigator technique.⁶

Localization of the Coronary Arteries
A plane through the major axis of the proximal RCA was identified with the use of a 3-point planscan tool to define the course of the proximal coronary arteries as depicted from a transverse 3D scan positioned about the base of the heart.⁷

Three-Dimensional Coronary MRA
Double oblique 3D bright-blood coronary MRA of the RCA was performed along the formerly identified long axis of the proximal coronary artery by use of an ECG-gated TFE/EPI sequence (repetition time [TR]=16 ms, echo time [TE]=5.1 ms, 3 excitations per shot, flip angle=40°, EPI factor=7, acquisition window 33 ms, field of view [FOV]=340 mm, scan matrix=256x177, in-plane resolution=1.3x1.9 mm², reconstructed slice thickness 1.5 mm, 21 slices).⁸ The total acquisition time for this scan was 3 minutes.

Three-Dimensional CMR Vessel Wall Imaging
The black-blood 3D CMR wall scan was performed in the same imaging plane as the 3D bright-blood coronary MRA. The black-blood properties were obtained with a modified local dual-inversion prepulse to null signal from blood and surrounding tissue.⁵ To suppress the signal from epicardial fat, a frequency-selective fat suppression prepulse was applied. A 3D spiral imaging sequence⁵ was used for the vessel wall imaging (TR=30 ms, TE=2 ms, acquisition window 60 ms, 26 slices with a thickness of 1 to 2 mm, FOV 400 to 512 mm, acquisition matrix 512x512, in-plane resolution 0.78 to 1.0x0.78 to 1.0 mm). The imaging time for this scan was 15 minutes.

Coronary Vessel Wall and Lumen Evaluation
For evaluation of the coronary vessel wall and lumen size, the 3D CMR vessel wall and coronary MRA datasets were reformatted along the major axis of the RCA on a commercial workstation (EasyVision 4.0, Philips Medical Systems). To minimize digitization errors and facilitate data analysis, the images were zoomed by a factor of 4 with the use of a fast Fourier transform algorithm.⁹ The average proximal vessel wall thickness and average luminal diameter along the entire visualized course of the RCA (inner and outer curvature) (Figures 1 and 2) were objectively determined with an automated edge-detection tool.¹⁰

View larger version (97K): [in this window] [in a new window]   Figure 1. Reformatted 3D coronary MRA (A) and local dual-inversion black-blood (B) vessel wall scans of the RCA in a healthy subject. Cross-sectional views at 3 levels are also shown (I, II, III).

View larger version (171K): [in this window] [in a new window]   Figure 2. X-ray angiography in 2 patients with (A) a focal 40% stenosis (white arrow) and (C) minor (10% stenoses) luminal irregularities (white arrows) of the proximal RCA. The corresponding black-blood 3D CMR vessel wall scans (B, D) demonstrate an irregularly thickened RCA wall (>2 mm) indicative of an increased atherosclerotic plaque burden. The inner and outer RCA walls are indicated by the white dotted arrows. The catheter size for the x-ray was 6F.

To visualize the whole circumference of the vessel wall, an animated sequence of cross-sectional views was generated (Movies I and II) from the 3D dataset perpendicular to the major axis of the vessel. On cross-sectional images of the RCA, the inner lumen and outer vessel borders were then manually segmented to determine coronary lumen and wall area.¹¹ The average area values were calculated from 4 equidistant cross-sectional images measured at 10-mm intervals.

Statistics
Continuous variables in patients and healthy subjects were compared with the use of a Wilcoxon rank-sum test, with significance at P0.05. The wall thickness was correlated by a linear regression analysis to the lumen diameter.

	Results

Top Abstract Introduction Methods Results Discussion References

 
All subjects completed CMR examination without complications. The 3D CMR vessel wall scans allowed for visualization of the contiguous proximal RCA in all patients and healthy subjects (52±13 versus 57±10 mm, P=0.47).

The coronary vessel wall appeared distinct from the surrounding epicardial fat and coronary blood (black lumen), and the 2D local dual-inversion pulse effectively suppressed unwanted signals outside the region of interest (Figures 1 and 2). Average signal-to-noise ratio of the RCA wall was similar for patients (35±11) and healthy subjects (36±18, P=0.58). The contrast-to-noise ratio between RCA wall/epicardial fat was 21±7 in the patients and 17±11 in the healthy subjects (P=0.23). The contrast-to-noise ratio between RCA wall/coronary blood was also similar for patients (23±10) and healthy subjects (24±8, P=0.81).

In the healthy subjects, the coronary wall appeared uniformly thin with homogenous signal intensity (Figure 1, Movie I). In the patients, focal thickening of the wall was noted especially at sites corresponding to luminal narrowing on the x-ray angiogram (Figure 2, Movie II).

Both mean vessel wall thickness (Figure 3) (1.7±0.3 versus 1.0±0.2 mm) and wall area (25.4±6.9 versus 11.5±5.2 mm²) were significantly increased in the patients with nonsignificant CAD compared with the healthy subjects (both P<0.01). The lumen diameter (Figure 4) (3.6±0.7 versus 3.4±0.5 mm, P=0.47) and lumen area (8.9±3.4 versus 7.9±3.5 mm², P=0.47) were similar in patients and healthy subjects. Thus, the ratio of coronary lumen/wall dimension was significantly reduced in the patients compared with healthy subjects (2.1±0.3 versus 3.7±0.9, P<0.01). There was no significant correlation (P=0.14) between vessel wall thickness and coronary MRA lumen diameter for the pooled data.

View larger version (14K): [in this window] [in a new window]   Figure 3. Average vessel wall thickness in patients vs healthy subjects showing increased wall thickness in patients.

View larger version (15K): [in this window] [in a new window]   Figure 4. Average MRA luminal diameter in patients vs healthy subjects showing no significant difference between the 2 groups.

	Discussion

Top Abstract Introduction Methods Results Discussion References

 
Our results demonstrate that the CMR approach identified an increased coronary vessel wall thickness with preservation of lumen size in patients with nonsignificant CAD, consistent with a Glagov-type outward arterial remodeling process. Outward or positive remodeling denotes an increase in total vessel size, whereas inward remodeling denotes a decrease in vessel size.¹² The concept of arterial remodeling as a compensatory response to atherosclerotic plaque growth has previously been observed exclusively from postmortem² or intravascular ultrasound¹³ studies. The critical importance of arterial remodeling and not plaque size as the primary determinant of lumen size in the presence of stable atherosclerotic lesions has only recently been recognized.¹² Furthermore, evidence that outward (rather than inward) arterial remodeling is more often associated with morphological predictors of plaque instability,¹⁴ and plaque rupture with subsequent acute coronary syndrome^3,4 has stimulated clinical interest in developing CMR as a noninvasive method to allow for serial studies of arterial remodeling in humans.

Other investigators who used 2D high-resolution transthoracic echocardiography found a significant increase in the left anterior descending (LAD) vessel wall thickness in patients with CAD compared with healthy subjects.¹⁵ Previous studies that used 2D black-blood CMR vessel wall imaging showed the potential of CMR to detect an increased wall thickness and wall area in patients with angiographically significant CAD.^11,16 In the present study, we focused on visualization of the RCA, though we have previously demonstrated the feasibility of this CMR approach for the LAD.⁵ The impact of spatial resolution on CMR evaluation of coronary atherosclerotic plaque burden was investigated showing that the current spatial resolution of 0.8 to 1x0.8 to 1x1 to 2 mm³ is associated with a relative overestimation of the wall area of 30% to 40% in patients versus 50% to 60% in healthy subjects.¹⁷ The proximal RCA wall thickness was measured by objective analysis along the entire visualized course and averaged to distinguish sub-pixel changes. The reported values of wall thickness therefore reflect the wall thickness throughout the vessel. The very irregular nature of wall thickening and the presence of minor x-ray angiographic luminal stenosis in all patients suggest that the increased wall thickness represents atherosclerosis. With the use of 2D echocardiography, other investigators have not found any systematic effect of age on wall thickness and external vessel diameter in healthy subjects or patients with CAD.¹⁵

Though unproven by the present study, CMR assessment of coronary wall thickness may prove useful for improved risk stratification in individual patients, thereby guiding early treatment and ultimately preventing acute coronary events. In addition, the natural history of coronary atherosclerosis could be studied noninvasively to further our understanding of the complex relationship between arterial remodeling, vessel inflammation, and plaque rupture.

	Footnotes

 
Drs Stuber, Börnert, and Botnar are employees of Philips Medical Systems.

Movies I and II are available in an online-only Data Supplement at http://www.circulationaha.org.

Received April 8, 2002; revision received May 29, 2002; accepted May 29, 2002.

	References

Top Abstract Introduction Methods Results Discussion References

 

1. Kim WY, Danias PG, Stuber M, et al. Coronary magnetic resonance angiography for the detection of coronary stenoses. N Engl J Med. 2001; 345: 1863–1869.[Abstract/Free Full Text]
   
2. Glagov S, Weisenberg E, Zarins CK, et al. Compensatory enlargement of human atherosclerotic coronary arteries. N Engl J Med. 1987; 316: 1371–1375.[Abstract]
   
3. Little WC, Constantinescu M, Applegate RJ, et al. Can coronary angiography predict the site of a subsequent myocardial infarction in patients with mild-to-moderate coronary artery disease? Circulation. 1988; 78: 1157–1166.[Abstract/Free Full Text]
   
4. Falk E, Shah PK, Fuster V. Coronary plaque disruption. Circulation. 1995; 92: 657–671.[Free Full Text]
   
5. Botnar RM, Kim WY, Stuber M, et al. 3D coronary vessel wall imaging utilizing a local inversion technique with spiral image acquisition. Magn Reson Med. 2001; 46: 848–854.[CrossRef][Medline] [Order article via Infotrieve]
   
6. Stuber M, Botnar RM, Danias PG, et al. Submillimeter three-dimensional coronary MR angiography with real-time navigator correction: comparison of navigator locations. Radiology. 1999; 212: 579–587.[Abstract/Free Full Text]
   
7. Stuber M, Botnar RM, Danias PG, et al. Double-oblique free-breathing high resolution three-dimensional coronary magnetic resonance angiography. J Am Coll Cardiol. 1999; 34: 524–531.[Abstract/Free Full Text]
   
8. Botnar RM, Stuber M, Danias PG, et al. A fast 3D approach for coronary MRA. J Magn Reson Imaging. 1999; 10: 821–825.[CrossRef][Medline] [Order article via Infotrieve]
   
9. Parker DL, Du YP, Davis WL. The voxel sensitivity function in Fourier transform imaging: applications to magnetic resonance angiography. Magn Reson Med. 1995; 33: 156–162.[Medline] [Order article via Infotrieve]
   
10. Botnar RM, Stuber M, Danias PG, et al. Improved coronary artery definition with T2-weighted, free-breathing, three-dimensional coronary MRA. Circulation. 1999; 99: 3139–3148.[Abstract/Free Full Text]
    
11. Botnar RM, Stuber M, Kissinger KV, et al. Noninvasive coronary vessel wall and plaque imaging with magnetic resonance imaging. Circulation. 2000; 102: 2582–2587.[Abstract/Free Full Text]
    
12. Ward MR, Pasterkamp G, Yeung AC, et al. Arterial remodeling. Mechanisms and clinical implications. Circulation. 2000; 102: 1186–1191.[Free Full Text]
    
13. Hermiller JB, Tenaglia AN, Kisslo KB, et al. In vivo validation of compensatory enlargement of atherosclerotic coronary arteries. Am J Cardiol. 1993; 71: 665–668.[CrossRef][Medline] [Order article via Infotrieve]
    
14. Burke AP, Kolodgie FD, Farb A. Morphological predictors of arterial remodeling in coronary atherosclerosis. Circulation. 2002; 105: 297–303.[Abstract/Free Full Text]
    
15. Gradus-Pizlo I, Sawada SG, Wright D, et al. Detection of subclinical coronary atherosclerosis using two-dimensional, high-resolution transthoracic echocardiography. J Am Coll Cardiol. 2001; 37: 1422–1429.[Abstract/Free Full Text]
    
16. Fayad ZA, Fuster V, Fallon JT, et al. Noninvasive in vivo human coronary artery lumen and wall imaging using black-blood magnetic resonance imaging. Circulation. 2000; 102: 506–510.[Abstract/Free Full Text]
    
17. Schaer M, Kim WY, Stuber M, et al. The impact of spatial resolution and respiratory motion on magnetic resonance plaque characterization. J Cardiovasc Magn Res. 2002; 4: 73–74.
    

This article has been cited by other articles:

				D. A. Bluemke, S. Achenbach, M. Budoff, T. C. Gerber, B. Gersh, L. D. Hillis, W. G. Hundley, W. J. Manning, B. F. Printz, M. Stuber, et al. Noninvasive Coronary Artery Imaging: Magnetic Resonance Angiography and Multidetector Computed Tomography Angiography: A Scientific Statement From the American Heart Association Committee on Cardiovascular Imaging and Intervention of the Council on Cardiovascular Radiology and Intervention, and the Councils on Clinical Cardiology and Cardiovascular Disease in the Young Circulation, July 29, 2008; 118(5): 586 - 606. [Full Text] [PDF]

				A. S. Astrup, W. Y. Kim, L. Tarnow, R. M. Botnar, C. Simonsen, L. Brix, L. Pietraszek, P. R. Hansen, W. J. Manning, and H.-H. Parving Relation of Left Ventricular Function, Mass, and Volume to NT-proBNP in Type 1 Diabetic Patients Diabetes Care, May 1, 2008; 31(5): 968 - 970. [Abstract] [Full Text] [PDF]

				S. B. Yeon, A. Sabir, M. Clouse, P. O. Martinezclark, D. C. Peters, T. H. Hauser, C. M. Gibson, R. Nezafat, D. Maintz, W. J. Manning, et al. Delayed-Enhancement Cardiovascular Magnetic Resonance Coronary Artery Wall Imaging: Comparison With Multislice Computed Tomography and Quantitative Coronary Angiography J. Am. Coll. Cardiol., July 31, 2007; 50(5): 441 - 447. [Abstract] [Full Text] [PDF]

				T. Saam, T. S. Hatsukami, N. Takaya, B. Chu, H. Underhill, W. S. Kerwin, J. Cai, M. S. Ferguson, and C. Yuan The Vulnerable, or High-Risk, Atherosclerotic Plaque: Noninvasive MR Imaging for Characterization and Assessment Radiology, July 1, 2007; 244(1): 64 - 77. [Abstract] [Full Text] [PDF]

				W. Y. Kim, A. S. Astrup, M. Stuber, L. Tarnow, E. Falk, R. M. Botnar, C. Simonsen, L. Pietraszek, P. R. Hansen, W. J. Manning, et al. Subclinical Coronary and Aortic Atherosclerosis Detected by Magnetic Resonance Imaging in Type 1 Diabetes With and Without Diabetic Nephropathy Circulation, January 16, 2007; 115(2): 228 - 235. [Abstract] [Full Text] [PDF]

				D. Maintz, M. Ozgun, A. Hoffmeier, R. Fischbach, W. Y. Kim, M. Stuber, W. J. Manning, W. Heindel, and R. M. Botnar Selective coronary artery plaque visualization and differentiation by contrast-enhanced inversion prepared MRI Eur. Heart J., July 2, 2006; 27(14): 1732 - 1736. [Abstract] [Full Text] [PDF]

				M. Y. Desai, S. Lai, C. Barmet, R. G. Weiss, and M. Stuber Reproducibility of 3D free-breathing magnetic resonance coronary vessel wall imaging Eur. Heart J., November 1, 2005; 26(21): 2320 - 2324. [Abstract] [Full Text] [PDF]

				V. Fuster, Z. A. Fayad, P. R. Moreno, M. Poon, R. Corti, and J. J. Badimon Atherothrombosis and High-Risk Plaque: Part II: Approaches by Noninvasive Computed Tomographic/Magnetic Resonance Imaging J. Am. Coll. Cardiol., October 4, 2005; 46(7): 1209 - 1218. [Abstract] [Full Text] [PDF]

				V. Fuster and R. J. Kim Frontiers in Cardiovascular Magnetic Resonance Circulation, July 5, 2005; 112(1): 135 - 144. [Full Text] [PDF]

				D. J. Pennell, U. P. Sechtem, C. B. Higgins, W. J. Manning, G. M. Pohost, F. E. Rademakers, A. C. van Rossum, L. J. Shaw, and E. K. Yucel Clinical indications for cardiovascular magnetic resonance (CMR): Consensus Panel report Eur. Heart J., November 1, 2004; 25(21): 1940 - 1965. [Full Text] [PDF]

				J. A.C. Lima and M. Y. Desai Cardiovascular magnetic resonance imaging: Current and emerging applications J. Am. Coll. Cardiol., September 15, 2004; 44(6): 1164 - 1171. [Abstract] [Full Text] [PDF]

				V. Mani, V. V. Itskovich, M. Szimtenings, J. G. S. Aguinaldo, D. D. Samber, G. Mizsei, and Z. A. Fayad Rapid Extended Coverage Simultaneous Multisection Black-Blood Vessel Wall MR Imaging Radiology, July 1, 2004; 232(1): 281 - 288. [Abstract] [Full Text] [PDF]

				S. Achenbach, D. Ropers, U. Hoffmann, B. MacNeill, U. Baum, K. Pohle, T. J. Brady, E. Pomerantsev, J. Ludwig, F. A. Flachskampf, et al. assessment of coronary remodeling in stenotic and nonstenotic coronary atherosclerotic lesions by multidetector spiral computed tomography J. Am. Coll. Cardiol., March 3, 2004; 43(5): 842 - 847. [Abstract] [Full Text] [PDF]

				M. Naghavi, P. Libby, E. Falk, S. W. Casscells, S. Litovsky, J. Rumberger, J. J. Badimon, C. Stefanadis, P. Moreno, G. Pasterkamp, et al. From Vulnerable Plaque to Vulnerable Patient: A Call for New Definitions and Risk Assessment Strategies: Part I Circulation, October 7, 2003; 108(14): 1664 - 1672. [Abstract] [Full Text] [PDF]

				E. M. Tuzcu and P. Schoenhagen Acute coronary syndromes, plaque vulnerability,and carotid artery disease: The changing role ofatherosclerosis imaging J. Am. Coll. Cardiol., September 17, 2003; 42(6): 1033 - 1036. [Full Text] [PDF]

				R. F. Redberg, R. A. Vogel, M. H. Criqui, D. M. Herrington, J. A. C. Lima, and M. J. Roman Task force #3--what is the spectrum of current and emerging techniques for the noninvasive measurement of atherosclerosis? J. Am. Coll. Cardiol., June 4, 2003; 41(11): 1886 - 1898. [Full Text] [PDF]

This Article Abstract Full Text (PDF) Data Supplement All Versions of this Article: 106/3/296    most recent 01.CIR.0000025629.85631.1Ev1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Kim, W. Y. Articles by Botnar, R. M. Search for Related Content PubMed PubMed Citation Articles by Kim, W. Y. Articles by Botnar, R. M. Related Collections Imaging CT and MRI Coronary circulation