251
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Nahrendorf M, Badea C, Hedlund LW, Figueiredo JL, Sosnovik DE, Johnson GA, Weissleder R. High-resolution imaging of murine myocardial infarction with delayed-enhancement cine micro-CT. Am J Physiol Heart Circ Physiol 2007; 292:H3172-8. [PMID: 17322414 PMCID: PMC2680216 DOI: 10.1152/ajpheart.01307.2006] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The objective of this study was to determine the feasibility of delayed-enhancement micro-computed tomography (microCT) imaging to quantify myocardial infarct size in experimental mouse models. A total of 20 mice were imaged 5 or 35 days after surgical ligation of the left coronary artery or sham surgery (n=6 or 7 per group). We utilized a prototype microCT that covers a three-dimensional (3D) volume with an isotropic spatial resolution of 100 microm. A series of image acquisitions were started after a 200 microl bolus of a high-molecular-weight blood pool CT agent to outline the ventricles. CT imaging was continuously performed over 60 min, while an intravenous constant infusion with iopamidol 370 was started at a dosage of 1 ml/h. Thirty minutes after the initiation of this infusion, signal intensity in Hounsfield units was significantly higher in the infarct than in the remote, uninjured myocardium. Cardiac morphology and motion were visualized with excellent contrast and in fine detail. In vivo CT determination of infarct size at the midventricular level was in good agreement with ex vivo staining with triphenyltetrazolium chloride [5 days post-myocardial infarction (MI): r(2)=0.86, P<0.01; 35 days post-MI: r(2)=0.92, P<0.01]. In addition, we detected significant left ventricular remodeling consisting of left ventricular dilation and decreased ejection fraction. 3D cine microCT reliably and rapidly quantifies infarct size and assesses murine anatomy and physiology after coronary ligation, despite the small size and fast movement of the mouse heart. This efficient imaging tool is a valuable addition to the current phenotyping armamentarium and will allow rapid testing of novel drugs and cell-based interventions in murine models.
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Affiliation(s)
- Matthias Nahrendorf
- Center for Molecular Imaging Research, Massachusetts General Hospital, Boston, MA, USA.
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252
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Paul JF, Abada HT. Strategies for reduction of radiation dose in cardiac multislice CT. Eur Radiol 2007; 17:2028-37. [PMID: 17318604 DOI: 10.1007/s00330-007-0584-3] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Revised: 12/20/2006] [Accepted: 01/09/2007] [Indexed: 01/15/2023]
Abstract
Because cardiac computed tomography (CT) (mainly coronary CT angiography) is a very promising technique, used more and more for coronary artery evaluation, the benefits and risks of this new low-invasive technique must be balanced. Radiation dose is a major concern for coronary CT angiography, especially in case of repeated examinations or in particular subgroups of patients (for example young female patients). Radiation dose to patient tends to increase from 16- to 64-slice CT. Radiation exposure in ECG-gated acquisitions may reach up to 40 mSv; considerable differences are attributable to the performance of CT machines, to technical dose-sparing tools, but also to radiological habits. Setting radiation dose at the lowest level possible should be a constant goal for the radiologist. Current technological tools are detailed in regard to their efficiency. Optimisation is necessary, by a judicious use of technological tools and also by individual adaptation of kV or mAs. This paper reviews the different current strategies for radiation dose reduction, keeping image quality constant. Data from the literature are discussed, and future technological developments are considered in regards to radiation dose reduction. The particular case of paediatric patients with congenital heart disease is also addressed.
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Affiliation(s)
- Jean-François Paul
- Department of Radiology, Centre Chirurgical Marie Lannelongue, 133 Avenue de la Résistance, 92350 Le Plessis-Robinson, France.
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253
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Mahnken AH, Bruners P, Mühlenbruch G, Emmerich M, Hohl C, Günther RW, Wildberger JE. Low Tube Voltage Improves Computed Tomography Imaging of Delayed Myocardial Contrast Enhancement in an Experimental Acute Myocardial Infarction Model. Invest Radiol 2007; 42:123-9. [PMID: 17220730 DOI: 10.1097/01.rli.0000251577.68223.84] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE We sought to evaluate the influence of tube voltage on the visualization of acute myocardial infarction (MI) in cardiac multislice spiral computed tomography (MSCT). MATERIALS AND METHODS Acute MI was induced in 12 domestic pigs by a 45-minute balloon occlusion of the left anterior descending artery. Delayed enhancement magnetic resonance imaging was performed 15 minutes after the injection of 0.2 mmol/kg Gd-DTPA. On the same day, retrospectively ECG-gated MSCT was performed at 120, 100, and 80 kV (16x0.75mm, 550mAseff.) 15 minutes after the injection of 140 mL of iopromide (1 g/iodine/kg). The pigs were killed and the hearts were excised and stained with 2,3,5-triphenyltetrazolium chloride. The area of acute MI, contrast-to-noise ratio (CNR), and percent signal difference were compared among the different imaging techniques by applying Bland-Altman plots and 2-way analysis of variance. RESULTS On MSCT at 120, 100, and 80 kV, the respective mean acute MI sizes were 18.4+/-11.4%, 19.3+/-11.5%, and 20.5+/-11.6%. The mean MI sizes were 20.8+/-12.2% and 20.1+/-12.4% on magnetic resonance imaging and 2,3,5-triphenyltetrazolium chloride staining. Analysis of variance did not show any statistically significant differences between the different techniques with respect to the size of acute MI (P=0.9880). Comparing the different kV settings on MSCT, the highest percent signal difference (74.7+/-12.1%) and the highest CNR (6.7+/-1.8) between infarcted and healthy remote myocardium were achieved at 80 kV. CONCLUSIONS When compared with routine scan protocols, low tube voltage MSCT allows for the assessment of the MI size with an improved CNR and contrast resolution. This technique appears to be advantageous for assessing myocardial viability from contrast enhanced late-phase MSCT.
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Affiliation(s)
- Andreas H Mahnken
- Helmholtz Institute, Applied Medical Engineering and Department of Diagnostic Radiology, RWTH Aachen University, Aachen, Germany.
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254
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Mahnken AH, Bruners P, Kinzel S, Katoh M, Mühlenbruch G, Günther RW, Wildberger JE. Late-phase MSCT in the different stages of myocardial infarction: animal experiments. Eur Radiol 2007; 17:2310-7. [PMID: 17268801 DOI: 10.1007/s00330-006-0569-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2006] [Revised: 11/01/2006] [Accepted: 12/21/2006] [Indexed: 10/23/2022]
Abstract
The purpose of this study was to intraindividually evaluate myocardial late enhancement on multislice spiral computed tomography (MSCT) for the assessment of the different stages of myocardial infarction (MI) in comparison with magnetic resonance (MR) imaging. Reperfused MI was successfully induced in seven pigs. Delayed enhancement MR imaging and late-phase MSCT were performed on day 0 as well as 7, 28 and 90 days after the procedure. The pigs were sacrificed, and 2,3,5-triphenyltetrazolin-chloride (TTC) staining was acquired. MI size was compared between the different imaging techniques and over time applying Bland-Altman plots and multivariate analysis with repeated measures. On day 0 the mean MI size was 23.7 +/- 11.8% of the left ventricular area on MSCT and 24.5 +/- 10.6% on MR imaging. On day 90 infarct sizes decreased significantly to 16.9 +/- 8.4% and 18.9 +/- 8.0%, respectively (P = 0.0019). On TTC staining the size of MI was 16.8 +/- 8.2%. Bland-Altman plots showed a good agreement between MSCT and MR imaging with mean deviations ranging from -3.4% to -1.9%. No significant difference between MSCT and MR imaging was found. Myocardial late enhancement on MSCT correlates well with delayed enhancement MR imaging during the different stages of MI and allows for reliable assessment of reperfused MI during acute, subacute and chronic stages.
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Affiliation(s)
- Andreas H Mahnken
- Department of Diagnostic Radiology, University Hospital, RWTH-Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany.
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255
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Abstract
Accurate distinction between viable and infarcted myocardium is important for assessment of patients who have cardiac dysfunction. Through the technique of delayed-enhancement MRI (DE-MRI), viable and infarcted myocardium can be simultaneously identified in a manner that closely correlates with histopathology findings. This article provides an overview of experimental data establishing the physiologic basis of DE-MRI-evidenced hyperenhancement as a tissue-specific marker of myocardial infarction. Clinical data concerning the utility of transmural extent of hyperenhancement for predicting response to medical and revascularization therapy are reviewed. Studies directly comparing DE-MRI to other viability imaging techniques are presented, and emerging applications for DE-MRI are discussed.
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Affiliation(s)
- Jonathan W Weinsaft
- Greenberg Division of Cardiology, Weill Medical College of Cornell University, 525 East 68th Street, Starr-4, New York, NY 10021, USA.
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256
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Kido T, Kurata A, Higashino H, Sugawara Y, Okayama H, Higaki J, Anno H, Katada K, Mori S, Tanada S, Endo M, Mochizuki T. Cardiac imaging using 256-detector row four-dimensional CT: preliminary clinical report. ACTA ACUST UNITED AC 2007; 25:38-44. [PMID: 17225052 DOI: 10.1007/s11604-006-0097-z] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Accepted: 10/07/2006] [Indexed: 12/14/2022]
Abstract
PURPOSE Along with the increase of detector rows on the z-axis and a faster gantry rotation speed, the spatial and temporal resolutions of the multislice computed tomography (CT) have been improved for noninvasive coronary artery imaging. We investigated the feasibility of the second specification prototype 256-detector row four-dimensional CT for assessing coronary artery and cardiac function. MATERIALS AND METHODS The subjects were five patients with coronary artery disease. Contrast medium (40-60 ml) was intravenously administered at the rate of 3-4 ml/s. The patient's whole heart was scanned for 1.5 s to cover at least one cardiac cycle during breathholding without electrocardiographic gating. Parameters used were 0.5 mm slice thickness, 0.5 s/rotation, 120 Kv, and 350 mA, with a half-scan reconstruction algorithm (temporal resolution 250 ms). Twenty-six transaxial datasets were reconstructed at intervals of 50 ms. RESULTS The assessability of the coronary arteries in AHA segments 1, 2, 3, 5, 6, 7, 9, and 11 was visually evaluated, resulting in 29 of 32 (90.9%) segments being assessable. Functional assessment was also performed using animated movies without banding artifacts in all cases. CONCLUSIONS The 256-detector row four-dimensional CT can assess the coronary artery and cardiac function using data during 1.5 s without banding artifacts.
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Affiliation(s)
- Teruhito Kido
- Department of Radiology, Ehime University School of Medicine, Shitsukawa, Toon 794-0295, Japan
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257
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Sievers B, Elliott MD, Hurwitz LM, Albert TSE, Klem I, Rehwald WG, Parker MA, Judd RM, Kim RJ. Rapid Detection of Myocardial Infarction by Subsecond, Free-Breathing Delayed Contrast-Enhancement Cardiovascular Magnetic Resonance. Circulation 2007; 115:236-44. [PMID: 17200443 DOI: 10.1161/circulationaha.106.635409] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
An ultrafast, delayed contrast-enhancement cardiovascular magnetic resonance technique that can acquire subsecond, “snapshot” images during free breathing (subsecond) is becoming widely available. This technique provides myocardial infarction (MI) imaging with complete left ventricular coverage in <30 seconds. However, the accuracy of this technique is unknown.
Methods and Results—
We prospectively compared subsecond imaging with routine breath-hold delayed contrast-enhancement cardiovascular magnetic resonance (standard) in consecutive patients. Two cohorts with unambiguous standards of truth were prespecified: (1) patients with documented prior MI (n=135) and (2) patients without MI and with low likelihood of coronary disease (lowest Framingham risk category; n=103). Scans were scored masked to identity and clinical information. Sensitivity, specificity, and accuracy of subsecond imaging for MI diagnosis were 87%, 96%, and 91%, respectively. Compared with the standard technique (98%, 100%, 99%), the subsecond technique had modestly reduced sensitivity (
P
=0.0001), but specificity was excellent. Missed infarcts were generally small or subendocardial (87%). Overall, regional transmural extent of infarction scores were highly concordant (2083/2294; 91%); however, 51 of 337 regions (15%) considered predominantly infarcted (>50% transmural extent of infarction) by the standard technique were considered viable (≤25% transmural extent of infarction) by the subsecond technique. Quantitative analysis demonstrated moderately reduced contrast-to-noise ratios for subsecond imaging between infarct and remote myocardium (12.0±7.2 versus 20.1±6.6;
P
<0.0001) and infarct and left ventricular cavity (−2.5±2.7 versus 3.6±3.7;
P
<0.0001).
Conclusions—
MI can be rapidly detected by subsecond delayed contrast-enhancement cardiovascular magnetic resonance during free breathing with high accuracy. This technique could be considered the preferred approach in patients who are more acutely ill or unable to hold their breath. However, compared with standard imaging, sensitivity is mildly reduced, and the transmural extent of infarction may be underestimated.
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Affiliation(s)
- Burkhard Sievers
- Duke Cardiovascular Magnetic Resonance Center, Durham, NC 27710, USA
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258
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Krombach GA, Niendorf T, Günther RW, Mahnken AH. Characterization of myocardial viability using MR and CT imaging. Eur Radiol 2007; 17:1433-44. [PMID: 17206427 DOI: 10.1007/s00330-006-0531-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Revised: 10/22/2006] [Accepted: 11/07/2006] [Indexed: 02/04/2023]
Abstract
Cardiovascular magnetic resonance (MR) imaging is of proven clinical value for the noninvasive characterization of myocardial viability. Computed tomography (CT) is also being exploited for this indication. Examples of each of these imaging strategies for the assessment of myocardial viability will be provided in this review. Key MRI concepts and practical considerations such as customized MR imaging techniques and tailored imaging protocols dedicated to viability assessment are outlined with the primary focus on recent developments. Clinical applications of MR-based viability assessment are reviewed, ranging from rapid functional cine imaging to tissue characterization using T2-weighted imaging and T1-weighted late-contrast-enhanced imaging. Next, the merits and limitations of state-of-the-art CT imaging are surveyed, and their implications for viability assessment are considered. The final emphasis is on current trends and future directions in noninvasive viability assessment using MRI and CT.
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Affiliation(s)
- Gabriele A Krombach
- Department of Diagnostic Radiology, RWTH Aachen University Hospital, Pauwelstrasse 30, 52057 Aachen, Germany.
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259
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Jung JI. The Effects of Trimetazidine on the Enhancement Patterns of Multi-Detector Computed Tomography in a Porcine Myocardial Infarction Model: What is the Meaning of the MDCT Enhancement Pattern in this Myocardial Infarction Model? Korean Circ J 2007. [DOI: 10.4070/kcj.2007.37.2.47] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Jung Im Jung
- Department of Radiology, St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
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260
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Pelzel JM, Lesser JR, Knickelbine T, Flygenring B, Tadros G, Schwartz RS. Multidetector CT coronary angiography: Where we are, and where we are going…. Catheter Cardiovasc Interv 2007; 69:159-71. [PMID: 17173314 DOI: 10.1002/ccd.20956] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jamie M Pelzel
- Division of Cardiovascular Disease, University of Minnesota, Minnesota, USA
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261
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Jacquier A, Higgins CB, Saeed M. MR imaging in assessing cardiovascular interventions and myocardial injury. CONTRAST MEDIA & MOLECULAR IMAGING 2007; 2:1-15. [PMID: 17326039 DOI: 10.1002/cmmi.122] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Performing an MR-guided endovascular intervention requires (1) real-time tracking and guidance of catheters/guide wires to the target, (2) high-resolution images of the target and its surroundings in order to define the extent of the target, (3) performing a therapeutic procedure (delivery of stent or injection of gene or cells) and (4) evaluating the outcome of the therapeutic procedure. The combination of X-ray and MR imaging (XMR) in a single suite was designed for new interventional procedures. MR contrast media can be used to delineate myocardial infarcts and microvascular obstruction, thereby defining the target for local delivery of therapeutic agents under MR-guidance. Iron particles, or gadolinium- or dysprosium-chelates are mixed with the soluble injectates or stem cells in order to track intramyocardial delivery and distribution. Preliminary results show that genes encoded for vascular endothelial and fibroblast growth factor and cells are effective in promoting angiogenesis, arteriogenesis, perfusion and LV function. Angiogenic growth factors, genes and cells administered under MR-guided minimally invasive catheter-based procedures will open up new avenues in treating end-stage ischemic heart disease. The optimum dose of the therapeutic agents, delivery devices and real-time imaging techniques to guide the delivery are currently the subject of ongoing research. The aim of this review is to (1) provide an updated review of experiences using MR imaging to guide transcatheter therapy, (2) address the potential of cardiovascular magnetic resonance (MR) imaging and MR contrast media in assessing myocardial injury at a molecular level and labeling cells and (3) illustrate the applicability of the non-invasive MR imaging in the field of angiogenic therapies through recent clinical and experimental publications.
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Affiliation(s)
- Alexis Jacquier
- Department of Radiology, University of California San Francisco, CA 94134-0628, USA
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262
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Graham JJ, Dick AJ. The Role of Noninvasive Imaging in Assessing Hemodynamically Significant Coronary Artery Stenoses. J Card Surg 2007; 22:67-9. [PMID: 17239219 DOI: 10.1111/j.1540-8191.2007.00346.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- John J Graham
- Division of Cardiology, Sunnybrook and Women's College Health Sciences Centre, Toronto, Ontario, Canada
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263
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de Roos A, Kroft LJM, Bax JJ, Geleijns J. Applications of multislice computed tomography in coronary artery disease. J Magn Reson Imaging 2007; 26:14-22. [PMID: 17659542 DOI: 10.1002/jmri.20971] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Multislice computed tomography (MSCT) provides high accuracy for noninvasive assessment of coronary artery disease (CAD). The introduction of the latest computed tomography (CT) technology allows comprehensive evaluation of various aspects of CAD, including the coronary calcium score, coronary artery stenoses, bypass patency, and myocardial function. Other applications, such as plaque characterization, first-pass perfusion imaging, and viability imaging using delayed contrast enhancement, are still under development and may demonstrate clinical utility in the future. Further improvements in CT hardware and imaging protocols are expected that may result in improved coronary artery imaging, new applications, and a significant reduction of radiation dose.
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Affiliation(s)
- Albert de Roos
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
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264
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Affiliation(s)
- Byoung Wook Choi
- Department of Radiology and Imaging Science, Yonsei University College of Medicine, Korea.
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265
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Lee SR, Jeong MH, Yim NY, Yoon NS, Kim KH, Hong YJ, Park HW, Kim JH, Moon JY, Ahn YK, Kim YH, Cho JG, Park JC, Kang JC. The Effects of Trimetazidine on the Enhancement Pattern of Multi-detector Computed Tomography in a Porcine Myocardial Infarction Model. Korean Circ J 2007. [DOI: 10.4070/kcj.2007.37.2.51] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Sang Rok Lee
- The Heart Center, Chonnam National University Hospital, Gwangju, Korea
| | - Myung Ho Jeong
- Chonnam National University Research Institute of Medical Sciences, Gwangju, Korea
| | - Nam Yeol Yim
- Department of Diagnostic Radiology, Chonnam National University Hospital, Gwangju, Korea
| | - Nam Sik Yoon
- The Heart Center, Chonnam National University Hospital, Gwangju, Korea
| | - Kye Hun Kim
- The Heart Center, Chonnam National University Hospital, Gwangju, Korea
| | - Young Joon Hong
- The Heart Center, Chonnam National University Hospital, Gwangju, Korea
| | - Hyung Wook Park
- Chonnam National University Research Institute of Medical Sciences, Gwangju, Korea
| | - Ju Han Kim
- The Heart Center, Chonnam National University Hospital, Gwangju, Korea
| | - Jae Youn Moon
- The Heart Center, Chonnam National University Hospital, Gwangju, Korea
| | - Young Keun Ahn
- Chonnam National University Research Institute of Medical Sciences, Gwangju, Korea
| | - Yun-Hyeon Kim
- Department of Diagnostic Radiology, Chonnam National University Hospital, Gwangju, Korea
| | - Jeong Gwan Cho
- Chonnam National University Research Institute of Medical Sciences, Gwangju, Korea
| | - Jong Chun Park
- Chonnam National University Research Institute of Medical Sciences, Gwangju, Korea
| | - Jung Chaee Kang
- Chonnam National University Research Institute of Medical Sciences, Gwangju, Korea
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266
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Brodoefel H, Klumpp B, Reimann A, Fenchel M, Heuschmid M, Miller S, Schroeder S, Claussen C, Scheule AM, Kopp AF. Sixty-four-MSCT in the characterization of porcine acute and subacute myocardial infarction: determination of transmurality in comparison to magnetic resonance imaging and histopathology. Eur J Radiol 2006; 62:235-46. [PMID: 17187952 DOI: 10.1016/j.ejrad.2006.11.031] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2006] [Revised: 11/22/2006] [Accepted: 11/24/2006] [Indexed: 02/07/2023]
Abstract
OBJECTIVE The aim of this study was to assess the accuracy of MSCT in characterizing myocardial infarction (MI) and, thereby, determine the extent of early perfusion defect (ED), microvascular obstruction (MO) and transmural depth of late enhancement (LE) in comparison to MRI and histology. MATERIALS AND METHODS Seven pigs were studied with MSCT (Somatom Sensation 64) and MRI (Magnetom Sonata) a median 1 and 21 days following temporary occlusion of a diagonal branch and creation of small reperfused infarction. For depiction of ED, CT images were acquired in the early arterial phase and following 35 s; LE and MO were evaluated on images obtained at 3, 5, 10 and 15 min. Thereby, a bolus/low-flow contrast injection protocol was used. Triphenyltetrazolium-chloride (TTC) stain and histology were obtained. Volumes of enhancement patterns were assessed as percentage of the ventricle and compared by Bland-Altman analysis. Segmental co-localization and graded transmurality was evaluated with weighted-kappa-test. RESULTS Close spatial agreement was observed for MRI-MO and MSCT-MO (bias=0.55; CI=-1.49 to 2.60 at 5 min MSCT), TTC and MSCT-LE (bias=-1.28; CI=-3.76 to 1.19) or MRI-LE and MSCT-LE (bias=-0.79; CI=-4.19 to 2.60). There was good segmental co-localization for MO (weighted kappa=0.93) and high agreement for transmural extent of TTC, MRI-LE and MSCT-LE (weighted kappa=0.84 TTC versus MSCT; 0.86 MRI versus MSCT). Arterial and 35s ED significantly underestimated infarct size and showed poor segmental or transmural agreement (weighted kappa=0.33; 0.44). CONCLUSIONS MSCT late-scans not only reliably depict size of MO and LE in acute or subacute infarct phases but, moreover, allow for accurate determination of LE transmurality.
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Affiliation(s)
- H Brodoefel
- Department of Diagnostic Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany.
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267
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Abstract
PURPOSE OF REVIEW Cardiac magnetic resonance imaging has an expanding role as a preferred modality for the detection and characterization of myocardial viability. RECENT FINDINGS Improving the accuracy of cardiac magnetic resonance for detecting viable myocardium has been one focus of investigators. In segments with intermediate transmurality of late gadolinium enhancement, dobutamine response improves the predictive power of cardiac magnetic resonance. A subtractive imaging technique with both short and long inversion times can enhance discrimination of subendocardial infarction and blood pool, but with increased noise and misregistration artifacts. Similar pharmacokinetics between cardiac magnetic resonance contrast agents and computed tomography contrast allows delayed enhancement imaging with computed tomography. Contrast between normal segments and scar remains vastly superior with cardiac magnetic resonance and no radiation is administered. Quantitation of blood flow demonstrated that resting myocardial blood flow is reduced in hibernating myocardium. SUMMARY Because of its safety, accuracy, ease of interpretation, and increasing availability, cardiac magnetic resonance-based assessment of myocardial viability has quickly transitioned from bench to bedside. Routine clinical implementation has prompted improved diagnostic capabilities and easier image interpretation. As a research tool, cardiac magnetic resonance continues to provide valuable insights into the fundamental nature of viability.
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Affiliation(s)
- David C Isbell
- Department of Medicine, University of Virginia Health System, Charlottesville, Virginia 22908, USA
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268
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Daghini E, Ritman EL, Lerman LO. Examine thy heart with all diligence: evaluation of cardiac function using fast computed tomography. Hypertension 2006; 49:249-56. [PMID: 17159086 DOI: 10.1161/01.hyp.0000253086.74365.52] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Elena Daghini
- Division of Nephrology and Hypertension, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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269
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Gibbons RJ, Araoz PA, Williamson EE. The year in cardiac imaging. J Am Coll Cardiol 2006; 48:2324-39. [PMID: 17161266 DOI: 10.1016/j.jacc.2006.09.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2006] [Accepted: 06/08/2006] [Indexed: 11/26/2022]
Affiliation(s)
- Raymond J Gibbons
- Division of Cardiovascular Diseases and Internal Medicine, Department of Medicine, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA.
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270
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Amado LC, Schuleri KH, Saliaris AP, Boyle AJ, Helm R, Oskouei B, Centola M, Eneboe V, Young R, Lima JAC, Lardo AC, Heldman AW, Hare JM. Multimodality noninvasive imaging demonstrates in vivo cardiac regeneration after mesenchymal stem cell therapy. J Am Coll Cardiol 2006; 48:2116-24. [PMID: 17113001 DOI: 10.1016/j.jacc.2006.06.073] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2006] [Revised: 06/06/2006] [Accepted: 06/29/2006] [Indexed: 01/12/2023]
Abstract
OBJECTIVES The purpose of this study was to test the hypothesis, with noninvasive multimodality imaging, that allogeneic mesenchymal stem cells (MSCs) produce and/or stimulate active cardiac regeneration in vivo after myocardial infarction (MI). BACKGROUND Although intramyocardial injection of allogeneic MSCs improves global cardiac function after MI, the mechanism(s) underlying this phenomenon are incompletely understood. METHODS We employed magnetic resonance imaging (MRI) and multi-detector computed tomography (MDCT) imaging in MSC-treated pigs (n = 10) and control subjects (n = 12) serially for a 2-month period after anterior MI. A sub-endocardial rim of tissue, demonstrated with MDCT, was assessed for regional contraction with MRI tagging. Rim thickness was also measured on gross pathological specimens, to confirm the findings of the MDCT imaging, and the size of cardiomyocytes was measured in the sub-endocardial rim and the non-infarct zone. RESULTS Multi-detector computed tomography demonstrated increasing thickness of sub-endocardial viable myocardium in the infarct zone in MSC-treated animals (1.0 +/- 0.2 mm to 2.0 +/- 0.3 mm, 1 and 8 weeks after MI, respectively, p = 0.028, n = 4) and a corresponding reduction in infarct scar (5.1 +/- 0.5 mm to 3.6 +/- 0.2 mm, p = 0.044). No changes occurred in control subjects (n = 4). Tagging MRI demonstrated time-dependent recovery of active contractility paralleling new tissue appearance. This rim was composed of morphologically normal cardiomyocytes, which were smaller in MSC-treated versus control subjects (11.6 +/- 0.2 mum vs. 12.6 +/- 0.2 mum, p < 0.05). CONCLUSIONS With serially obtained MRI and MDCT, we demonstrate in vivo reappearance of myocardial tissue in the MI zone accompanied by time-dependent restoration of contractile function. These data are consistent with a regenerative process, highlight the value of noninvasive multimodality imaging to assess the structural and functional basis for myocardial regenerative strategies, and have potential clinical applications.
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Affiliation(s)
- Luciano C Amado
- Department of Medicine, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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271
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Mahnken AH, Mühlenbruch G, Günther RW, Wildberger JE. Cardiac CT: coronary arteries and beyond. Eur Radiol 2006; 17:994-1008. [PMID: 17066290 DOI: 10.1007/s00330-006-0433-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2006] [Revised: 08/01/2006] [Accepted: 08/07/2006] [Indexed: 10/24/2022]
Abstract
Multi-detector-row computed tomography (MDCT) has emerged as a rapidly developing method for non-invasive imaging of the heart. An understanding of ECG synchronization, contrast material administration, patient preparation and image post-processing is needed to optimize image quality. The basic technical principles and essentials of these technical basics are described here. Correctly applied cardiac MDCT allows imaging of the coronary arteries including coronary anatomy and stenosis detection. The same is true for evaluation of coronary artery bypass grafts and, to some extent, coronary artery stents. While quantification of total calcified plaque burden has been long established, coronary MDCT allows assessing plaque morphology and constitution. Recent approaches go beyond the coronaries and include evaluation of left ventricular function at rest and myocardial viability. In combination with experimental approaches for assessing aortic valve function and myocardial perfusion imaging, cardiac MDCT offers the potential for a comprehensive examination of the heart using a single breath-hold examination.
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Affiliation(s)
- Andreas H Mahnken
- Department of Diagnostic Radiology, University Hospital, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany.
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272
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Senior R. Diagnostic and imaging considerations: role of viability. Heart Fail Rev 2006; 11:125-34. [PMID: 16937031 DOI: 10.1007/s10741-006-9483-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Left ventricular systolic dysfunction is a recognised feature of heart failure. In developed nations, the leading cause of left ventricular systolic dysfunction is coronary artery disease. Revascularisation is a treatment strategy for patients with predominant symptoms of heart failure and significant left ventricular dysfunction. Presence or absence of myocardial viability has been shown to affect outcome after revascularisation. There are various techniques to assess myocardial viability. However, limitations of current literature, lack of completed randomised trials and high peri-procedural trials create significant uncertainty about the optimal strategy. This review focuses on the role of non-invasive testing for myocardial viability in patients with left ventricular systolic dysfunction and heart failure and also outlines the pros and cons of each technique.
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Affiliation(s)
- Roxy Senior
- Department of Cardiovascular Medicine, Northwick Park Hospital, Watford Road, Harrow Middlesex, HA1 3UJ, United Kingdom.
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273
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Baks T, Cademartiri F, Moelker AD, Weustink AC, van Geuns RJ, Mollet NR, Krestin GP, Duncker DJ, de Feyter PJ. Multislice Computed Tomography and Magnetic Resonance Imaging for the Assessment of Reperfused Acute Myocardial Infarction. J Am Coll Cardiol 2006; 48:144-52. [PMID: 16814660 DOI: 10.1016/j.jacc.2006.02.059] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Revised: 02/10/2006] [Accepted: 02/21/2006] [Indexed: 01/07/2023]
Abstract
OBJECTIVES We evaluated the accuracy of in vivo delayed-enhancement multislice computed tomography (DE-MSCT) and delayed-enhancement magnetic resonance imaging (DE-MRI) for the assessment of myocardial infarct size using postmortem triphenyltetrazolium chloride (TTC) pathology as standard of reference. BACKGROUND The diagnostic value of DE-MSCT for the assessment of acute reperfused myocardial infarction is currently unclear. METHODS In 10 domestic pigs (25 to 30 kg), the circumflex coronary artery was balloon-occluded for 2 h followed by reperfusion. After 5 days (3 to 7 days), DE-MRI (1.5-T) was performed 15 min after administration of 0.2 mmol/kg gadolinium-DTPA using an inversion recovery gradient echo technique. On the same day, DE-MSCT (64-slice) was performed 15 min after administration of 1 gI/kg of iodinated contrast material. One day after imaging, hearts were excised, sectioned in 8 mm short-axis slices, and stained with TTC. Infarct size was defined as the hyperenhanced area on DE-MSCT and DE-MRI images and the TTC-negative area on TTC pathology slices. Infarct size was expressed as percentage of total slice area. RESULTS Infarct size determined by DE-MSCT and DE-MRI showed a good correlation with infarct size assessed with TTC pathology (R2 = 0.96 [p < 0.001] and R(2) = 0.93 [p < 0.001], respectively). The correlation between DE-MSCT and DE-MRI was also good (R2 = 0.96; p < 0.001). The relative difference in CT attenuation value of infarcted myocardium compared to remote myocardium was 191 +/- 18%. The relative MR signal intensity between infarcted myocardium and remote myocardium was 554 +/- 156%. CONCLUSIONS We demonstrated that DE-MSCT can assess acute reperfused myocardial infarction in good agreement with in vivo DE-MRI and TTC pathology.
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Affiliation(s)
- Timo Baks
- Department of Cardiology, Thoraxcenter, Erasmus University Medical Center, Rotterdam, The Netherlands
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274
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Brodoefel H, Klumpp B, Reimann A, Ohmer M, Fenchel M, Schroeder S, Miller S, Claussen C, Kopp AF, Scheule AM. Late myocardial enhancement assessed by 64-MSCT in reperfused porcine myocardial infarction: diagnostic accuracy of low-dose CT protocols in comparison with magnetic resonance imaging. Eur Radiol 2006; 17:475-83. [PMID: 16802125 DOI: 10.1007/s00330-006-0334-y] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2005] [Revised: 04/23/2006] [Accepted: 05/08/2006] [Indexed: 02/06/2023]
Abstract
The purpose was to assess the practicability of low-dose CT imaging of late enhancement in acute infarction. Following temporary occlusion of the second diagonal branch, seven pigs were studied by multislice computed tomography (MSCT) and magnetic resonance imaging (MRI). Thus, 64-slice CT was performed at 3, 5, 10 and 15 min following the injection of contrast medium according to a bolus/low-flow protocol. Standard parameters of 120 kV and 800 mAs were compared with 80 kV and 400 mAs in various combinations. Infarct volumes were assessed as percentage of the ventricle for both MSCT and MR images. CT density values for viable and infarcted myocardium were obtained and image quality assessed. Mean infarct volume as measured by MRI was 12.33+/-7.06%. MSCT achieved best correlation of volumes at 5 and 10 min. Whilst lowering of tube current resulted in poor correlation, tube voltage did not affect accuracy of infarct measurement (r (2)=0.92 or 0.93 at 5 min, 800 mAs and 80 or 120 kV). In terms of image quality, greater image noise with 80 kV was compensated by significantly better contrast enhancement between viable and non-viable myocardium at lower voltage. Myocardial viability can accurately be assessed by MSCT at 80 kV, which ensures higher contrast for late enhancement and yields good correlation with MRI.
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Affiliation(s)
- H Brodoefel
- Department of Diagnostic Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany.
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275
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George RT, Silva C, Cordeiro MAS, DiPaula A, Thompson DR, McCarthy WF, Ichihara T, Lima JAC, Lardo AC. Multidetector computed tomography myocardial perfusion imaging during adenosine stress. J Am Coll Cardiol 2006; 48:153-60. [PMID: 16814661 DOI: 10.1016/j.jacc.2006.04.014] [Citation(s) in RCA: 186] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2005] [Revised: 02/28/2006] [Accepted: 03/08/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVES The purpose of this study is to validate the accuracy of multidetector computed tomography (MDCT) to measure differences in regional myocardial perfusion during adenosine stress in a canine model of left anterior descending (LAD) artery stenosis, during first-pass, contrast-enhanced helical MDCT. BACKGROUND Myocardial perfusion imaging by MDCT may have significant implications in the diagnosis and treatment of coronary artery disease. METHODS Eight dogs were prepared with a LAD stenosis, and contrast-enhanced MDCT imaging was performed 5 min into adenosine infusion (0.14 to 0.21 mg/kg/min). Images were analyzed using a semiautomated approach to define the regional signal density (SD) ratio (myocardial SD/left ventricular blood pool SD) in stenosed and remote territories, and then compared with microsphere myocardial blood flow (MBF) measurements. RESULTS Mean MBF in stenosed versus remote territories was 1.37 +/- 0.46 ml/g/min and 1.29 +/- 0.48 ml/g/min at baseline (p = NS) and 2.54 +/- 0.93 ml/g/min and 8.94 +/- 5.74 ml/g/min during adenosine infusion, respectively (p < 0.05). Myocardial SD was 92.3 +/- 39.5 HU in stenosed versus 180.4 +/- 41.9 HU in remote territories (p < 0.001). There was a significant linear association of the SD ratio with MBF in the stenosed territory (R = 0.98, p = 0.001) and between regional myocardial SD ratio and MBF <8 ml/g/min, slope = 0.035, SE = 0.007, p < 0.0001. Overall, there was a significant non-linear relationship over the range of flows studied (LR chi-square [2 degrees of freedom] = 31.8, p < 0.0001). CONCLUSIONS Adenosine-augmented MDCT myocardial perfusion imaging provides semiquantitative measurements of myocardial perfusion during first-pass MDCT imaging in a canine model of LAD stenosis.
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Affiliation(s)
- Richard T George
- Department of Medicine, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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276
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Cordeiro MAS, Lima JAC. Atherosclerotic Plaque Characterization by Multidetector Row Computed Tomography Angiography. J Am Coll Cardiol 2006; 47:C40-7. [PMID: 16631509 DOI: 10.1016/j.jacc.2005.09.076] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Revised: 09/13/2005] [Accepted: 09/26/2005] [Indexed: 01/01/2023]
Abstract
Multidetector row computed tomography angiography (MDCTA) is seen as a potential alternative to current imaging methods for the assessment of vessel anatomy and atherosclerotic plaque composition/morphology in a great variety of arterial beds. Recent advances represented by the increase in gantry speed to <500 ms per rotation and in the number of detector rows from 4 to 64, in addition to the decrease in slice thickness to submillimetric levels, brought significant improvement in diagnostic accuracy by coronary MDCTA. In general, it has a good correlation with both intravascular ultrasound (IVUS) and histopathology for discrimination between soft, intermediate, and calcified plaques. Plaque area and volume tend to be underestimated by 12-detector row MDCTA and overestimated by 16-detector row MDCTA, but the number of patients studied so far is relatively small. However, it seems that 64-detector row MDCTA can measure plaque area and volume with greater accuracy. Plaque remodeling is overestimated in small vessels by 12-detector row MDCTA, whereas 16- and 64-detector row MDCTA show a good correlation with IVUS. Although still under development, the potential of MDCTA to characterize atherosclerotic plaque composition as well as to precisely determine plaque area, volume, and remodeling in the future is quite promising.
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Affiliation(s)
- Marco A S Cordeiro
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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