| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Cardiac Imaging |
1 From the Departments of Cardiology (G.K.L., J.H.G., T.M.), Diagnostic and Interventional Radiology (A.S., M.P.B., J.H.G., G.A.), and Nuclear Medicine (V.M., J.M.), University Hospital Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany; and Department of Radiology, University of California, San Francisco (M.S., C.B.H.). From the 2002 RSNA scientific assembly. Received July 18, 2003; revision requested October 2; revision received October 29; accepted January 5, 2004. Supported in part by Schering, Berlin, Germany, and by the Pinguin Stiftung Düsseldorf, Germany. Address correspondence to G.K.L. (e-mail: glund@uke.uni-hamburg.de).
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSIONAPPENDIXREFERENCES |
|---|
MATERIALS AND METHODS: Contrast material–enhanced FPE MR, inversion-recovery DE MR, and rest-redistribution 201Tl SPECT images were obtained in 60 consecutive patients (53 men, seven women; mean age [± SD], 56 years ± 13; range, 30–78 years) at 6 days ± 3 after reperfused first myocardial infarction. Presence of microvascular obstruction was determined on FPE MR images. Infarct size was defined on DE MR images as percentage of left ventricular (LV) area and compared with uptake defect on redistribution 201Tl SPECT images. Differences in continuous data were analyzed with Student t test. Linear regression and Bland-Altman analysis were used to compare measurements of infarct size.
RESULTS: Mean infarct size was not significantly different between DE MR imaging (20.7% ± 11.5% of LV area) and 201Tl SPECT (19.4% ± 14.3% of LV area; P = .26); good correlation (r = 0.73; P < .001) and agreement were found, with a mean difference of +1.3% ± 9.8% of LV area. 201Tl SPECT failed to depict infarct in six (20%) of 30 patients with inferior myocardial infarction (mean size, 6.4% ± 5.7% of LV area on DE MR images), whereas DE MR images showed the infarct in all patients (P < .01). FPE MR images depicted microvascular obstruction in 23 (38%) of 60 patients; these patients had larger infarctions at DE MR imaging than did patients without microvascular obstruction (30.4% ± 9.0% vs 15.1% ± 8.4% of LV area, P < .001). 201Tl SPECT showed larger infarcts in patients with microvascular obstruction (26.7% ± 16.2% vs 15.0% ± 11.2% of LV area, P < .01).
CONCLUSION: Good correlation and agreement with 201Tl SPECT indicate DE MR imaging may be used to estimate infarct size 6 days after reperfused acute myocardial infarction. DE MR imaging is more sensitive for detection of inferior infarction than is 201Tl SPECT. Patients with microvascular obstruction on FPE MR images have larger infarcts.
© RSNA, 2004
Index terms: Coronary vessels, stenosis or obstruction, 54.771 • Myocardium, infarction, 511.771 • Myocardium, MR, 511.121413, 511.12143 • Myocardium, SPECT, 511.12162 • Single photon emission computed tomography (SPECT), comparative studies, 511.121413, 511.12162
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSIONAPPENDIXREFERENCES |
|---|
Contrast material–enhanced MR imaging also has the potential to allow identification of regional microvascular obstruction at first-pass enhancement (FPE) (6,10,11). The phenomenon of microvascular obstruction frequently occurs in the first few days after acute myocardial infarction, despite successful revascularization of the infarct-related artery (12). Results of experimental studies have shown that microvascular obstruction is related to endothelial swelling, to myocyte edema, and to obstruction of the capillaries by neutrophils, erythrocytes, and debris (12). Presence of microvascular obstruction is associated with greater myocardial damage, based on electrocardiographic and echocardiographic criteria (3,11). Furthermore, results of clinical studies have indicated that microvascular obstruction is associated with left ventricular (LV) remodeling and increased risk of mortality and morbidity (11,13).
Acute infarct size estimated at 201Tl SPECT has close correlation with true infarct size obtained from pathologic specimens (14). In humans, defect size at 201Tl SPECT correlates well with other physiologic measurements, including myocardial enzyme release (15,16) and LV ejection fraction (16), as well as with infarct size at technetium 99m sestamibi (17,18). Results of studies performed in patients with acute myocardial infarction have shown that the redistribution images allow one to accurately distinguish viable from scarred myocardium, whereas the early images may lead to underestimation of infarct size (19). SPECT is widely used to estimate infarct size after reperfusion therapy (19) and to predict outcome according to infarct size (20).
The purpose of our study was to evaluate patients with acute myocardial infarction by using FPE and DE MR imaging in comparison with 201Tl SPECT.
|
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSIONAPPENDIXREFERENCES |
|---|
Coronary angiography was performed in all patients to identify the infarct-related artery. Perfusion of the infarct-related artery was determined at consensus reading by two observers (G.K.L. and M.P.B., 10 and 2 years of experience reading coronary angiograms, respectively) by using the Thrombolysis in Myocardial Infarction (TIMI) trial criteria (see Appendix). Subsequently, the infarct-related artery underwent revascularization in all patients with reduced TIMI flow before the imaging examinations were performed. MR imaging and SPECT were performed within 24 hours and later than 3 days after myocardial infarction. Two patients discontinued MR imaging because of claustrophobia, and another patient withdrew informed consent to 201Tl SPECT. No patient was excluded for reasons of technical or image quality.
Thus, 60 patients completed the study. There were 53 men and seven women, with a mean age (± SD) of 56 years ± 13 (age range, 30–78 years). Age among men (mean age, 57 years ± 12; age range, 30–78 years) was not statistically different from that among women (mean age, 53 years ± 15; age range, 32–75 years; P = .42). Furthermore, no other patient characteristics were statistically different between the men and women. Q-wave infarction was present in 38 patients (63%). Peak CK level was 1,038 U/L ± 840, with a peak CK-MB isoenzyme level of 112 U/L ± 71. The infarct-related artery was the left anterior descending artery in 30 (50%), the right coronary artery in 17 (28%), and the circumflex artery in 13 patients (22%). In 47 patients (78%), myocardial infarction was successfully treated with direct angioplasty. In one patient scheduled to undergo direct angioplasty, revascularization was not performed because this patient had a spontaneous thrombolysis with TIMI flow grade 3 and no restenosis. The remaining 12 patients received thrombolytic agents, and revascularization was performed before the imaging procedures at 6 days ± 4 after infarction by means of angioplasty (n = 11) or bypass surgery (n = 1). Examinations with both imaging modalities were performed at 6 days ± 3 (range, 3–14 days) after infarction.
MR Imaging
MR imaging was performed with a 1.5-T system (Vision; Siemens Medical Systems, Erlangen, Germany) by using a phased-array chest coil and electrocardiographic triggering. All images were acquired during breath-hold sequences in double oblique planes along the short axis of the LV. FPE MR imaging was used to detect regional microvascular obstruction, whereas DE MR imaging was used to estimate infarct size. For FPE MR imaging, a bolus of 0.1 mmol of gadopentetate dimeglumine (Magnevist; Schering, Berlin, Germany) per kilogram of body weight was injected into an antecubital vein, followed by saline solution. Injection was performed at 3 mL/sec with a power injector (Spectris; Medrad, Indianola, Pa). Immediately after injection, one image per R-R interval was acquired for the next 60 heartbeats at a single midventricular section along the short axis by using a T1-weighted turbo fast low-angle shot sequence with a 90° saturation-recovery preparatory pulse. Imaging parameters were as follows: repetition time, 2.4 msec; echo time, 1.2 msec; effective inversion time, 118 msec; section thickness, 10 mm; field of view, 350 x 306 mm (7/8 rectangular field of view); image matrix, 128 x 90; and pixel size, 2.7 x 3.4 mm.
At 10 minutes after injection, DE MR imaging was performed in three short-axis LV sections at the apical, midventricular, and basal levels by using a T1-weighted turbo fast low-angle shot sequence with a segmented 180° inversion-recovery preparatory pulse (21). Imaging parameters were as follows: repetition time, 7.6 msec; echo time, 3.4 msec; inversion time, 220–300 msec to null the signal intensity of normal myocardium; delay after trigger, 400 msec; section thickness, 6 mm; field of view, 350 x 262 mm (6/8 rectangular field of view); image matrix, 256 x 132; and pixel size, 1.37 x 2.0 mm. Images were obtained every other heartbeat to allow time for more complete inversion recovery.
MR Data Analysis
MR images were transferred to a computer (Macintosh; Apple Computer, Cupertino, Calif), and data analysis was performed by using a public domain program (NIH Image, version 1.62; U.S. National Institutes of Health; available at rsb.info.nih.gov/nih-image). All MR measurements were performed independently by two of three observers (G.K.L., A.S., and M.P.B., with 5, 3, and 2 years of experience interpreting cardiac MR images, respectively) who were blinded to the results of 201Tl SPECT, as well as to all clinical data. MR data are given as mean values from the two readings. Microvascular obstruction was identified on single-section FPE MR images as an area of persistent subendocardial hypoenhancement with signal intensity more than 2 SDs lower than that of the surrounding hyperenhanced myocardium (22). The size of microvascular obstruction was measured on the image that showed peak enhancement in remote normal myocardium. Delayed hyperenhancement was considered present if the signal intensity was more than 2 SDs higher than that of remote normal myocardium on DE MR images (22). Images were thresholded to these levels, and the size of microvascular obstruction and infarct was measured and expressed as a percentage of the LV area. On DE MR images, the size of a zone of persistent subendocardial hypoenhancement within a hyperenhanced area was also measured, and this area was included in measurements of infarct size (23).
201Tl SPECT
Patients underwent 201Tl SPECT at rest after injection of 1 MBq (0.03 mCi) of 201Tl (Bristol-Myers Squibb Pharma, Brussels, Belgium) per kilogram of body weight. Rest-redistribution images were acquired 4 hours after injection; images were acquired with a dual-head gamma camera equipped with a low-energy high-spatial-resolution collimator (ECAM; Siemens Medical Systems). Thirty-two projections were acquired over a 90° arc, with an acquisition time of 40 seconds each. Transverse images were reconstructed in a 64 x 64-pixel matrix by using a filtered back projection with a Butterworth filter with an order of 5 and a cutoff frequency of 0.5 cycles per pixel. SPECT images were independently evaluated by one observer (V.M., 5 years of experience interpreting cardiac SPECT images) who was blinded to all other data by using a polar projection–based image analysis program (4D-MSPECT; University of Michigan, Ann Arbor). A volumetric sampling algorithm was used to delineate a maximum count surface, which was transformed into a polar map. Each polar map was normalized to maximum uptake of the tracer. Infarct size was calculated as a percentage of the LV area by using an uptake threshold more than –2.5 SDs (24,25) below the normal threshold established at the University of Michigan.
Statistical Analysis
Continuous data are expressed as mean ± SD. Differences in continuous data between or within groups were analyzed by using the Student t test for unpaired or paired data, respectively. Categorical variables were analyzed by using the 
2 test. Linear regression and Bland-Altman analysis were used for analysis of correlation and agreement in measurements of infarct size. Concordance between microvascular obstruction on FPE MR images and persistent hypoenhancement on DE MR images was analyzed by using 
statistics for paired data. Diagnostic accuracy of DE MR imaging in the detection of microvascular obstruction was calculated, including the corresponding 95% CIs. P < .05 was required to show statistical significance.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSIONAPPENDIXREFERENCES |
|---|
|
|
|
|
|
|
value, 0.71). Discordant findings were present in eight patients; in six of these patients, microvascular obstruction was depicted on FPE MR images, but no persistent hypoenhancement was seen on DE MR images. In the remaining two patients, no microvascular obstruction was observed on FPE MR images, but DE MR images revealed persistent hypoenhancement. One of these two patients had an anterior infarction, and DE MR images showed persistent hypoenhancement only in the apical section, whereas the other patient with inferior infarction had persistent hypoenhancement solely in the basal section on DE MR images.
|
|
Size of Myocardial Infarct
Patients with microvascular obstruction had larger infarcts at DE MR imaging in comparison with patients without obstruction (30.4% ± 9.0% vs 15.1% ± 8.4% of the LV area; P < .001; Fig 6). Use of 201Tl SPECT confirmed larger infarcts in patients with microvascular obstructions (26.7% ± 16.2% vs 15.0% ± 11.2% of the LV area; P < .01). Presence of microvascular obstruction was indicative of a large infarct (ie, infarct size larger than 20% of the LV area). Twenty (87%) of 23 patients with microvascular obstruction had large infarcts compared with those in 11 (30%) of 37 patients without microvascular obstruction (P < .001).
|
|
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSIONAPPENDIXREFERENCES |
|---|
Correlation between DE MR Imaging and 201Tl SPECT
A number of animal studies have been performed to analyze the accuracy of DE MR imaging with gadopentetate dimeglumine to quantify the size of acute myocardial infarction (5,7–9,23,26). These studies revealed confounding results; results of some studies demonstrated excellent correlation between DE MR imaging and histopathologic validation (23,26), whereas results of other studies indicated that DE MR images may cause overestimation of infarct size by 12%–40% of the LV area (5–9). Results of two animal studies showed that the time point of MR imaging after injection of gadopentetate dimeglumine is crucial for the accuracy of DE MR imaging after acute infarction (7,8). In one of these studies, in which spin-echo MR imaging and a constant inversion time were used, the gadolinium-enhanced region caused the true infarct size to be greatly overestimated when imaging was performed immediately after injection of the contrast medium (8). The enhanced region gradually receded, and estimation closely matched true infarct size after an elapsed time of 21 minutes ± 4. Similar data were determined in a study by Ni et al (7). By using an inversion-recovery turbo fast low-angle shot sequence, Ni et al revealed that the agreement between DE MR imaging and true infarct size was closest at 30 minutes after administration of the contrast medium. Possible explanations for overestimation early after the occurrence of acute myocardial infarction include (a) an altered washout characteristic of the contrast medium in ischemically injured but viable myocardium compared with necrotic myocardium or (b) an increased distribution volume for gadopentetate dimeglumine in the edematous but viable periinfarction zone (5).
Our study, performed in humans, revealed good agreement between 201Tl SPECT and DE MR imaging with a delay of 10 minutes between injection of contrast medium and start of MR imaging. This good agreement may be related to the use of a variable inversion time for nulling the signal intensity of normal myocardium after contrast medium injection. Authors of one recent study emphasized the importance of adjusting the inversion time after administration of contrast medium because the concentration of gadopentetate dimeglumine decreases continuously after injection (21). Another possible explanation is that, in our study, MR imaging was performed at a later time after infarction compared with that in the animal studies in which infarct overestimation was demonstrated. In those studies, MR imaging was performed early, within the first 48 hours after infarction (5–9). Prolonged reperfusion may eliminate the edematous periinfarction zone and may improve the accuracy of infarct size measurement. Results of a previous study support the notion that the rate of infarct size overestimation with DE MR imaging decreases within days after infarction (9). In that study, a significant reduction in overestimation of infarct size was found, from 12.4% to 8.3% of the LV area measured within the first 24 hours of reperfusion.
Although a large number of animal studies have been performed, to our knowledge, there has been only one prior human study in which the accuracy of DE MR imaging was compared with that of a nuclear imaging technique to estimate acute infarct size (3). In that study, 12 patients were examined at DE MR imaging and at stress-redistribution 201Tl SPECT. Size of myocardial infarct was estimated at a single midventricular level with use of each method. Results of that study also showed good correlation between DE MR imaging and stress-redistribution 201Tl SPECT (r = 0.92; P < .001). The large number of patients evaluated in our study permits greater confidence in the results of DE MR imaging, as well as testing of the method in a wide range of infarct sizes. Unlike measurements in previous studies (3,27), quantitative measurements were performed in our study in multiple sections by two observers using a threshold method to distinguish between infarction and normal myocardium. With this approach, a low mean difference was found between observers, which underlines the reproducibility of the MR measurements. The close agreement between the results of 201Tl SPECT and DE MR imaging demonstrates the clinical usefulness of MR imaging for estimating the size of acute myocardial infarcts. However, at this stage it is not clear whether the regions measured with the two modalities represented only nonviable myocardium or also included a periinfarction zone of viable myocardium. Future MR studies that include administration of a necrosis-specific contrast medium may be useful for addressing this issue.
DE MR imaging was more sensitive in demonstrating small inferior infarcts than was 201Tl SPECT. Our finding has been recently confirmed by Wagner et al (28) in a study of patients with chronic myocardial infarction. Detection of small infarcts is important because patients with previous infarction are at a high risk for recurrent infarction and death (29). The higher sensitivity of DE MR imaging is a result of several factors. First, 201Tl SPECT has limited ability to measure tracer uptake in the inferior myocardium because of diaphragmatic photon attenuation. Second, mean 201Tl uptake is lower and has a larger SD in the inferior wall compared with that in the anterior wall (30). The larger SD of tracer uptake results in an increased threshold, which most likely causes the reduced sensitivity of 201Tl SPECT in depicting small inferior infarcts. Third, 201Tl SPECT has limited spatial resolution, with a pixel size approximately 60 times larger than that at DE MR imaging, which also may have prevented detection of small infarcts (29).
Effect of Microvascular Obstruction on Infarct Size
Previous studies have shown that patients with microvascular obstruction have larger areas of myocardial damage according to electrocardiographic and echocardiographic criteria (3) and measurement of infarct size (11). The data from our study confirm previous findings and extend the knowledge about the association between microvascular obstruction and infarct size. Patients with microvascular obstruction had larger infarcts, quantified with three independent methods, compared with patients without microvascular obstruction. Quantitative measurement showed that almost all patients with microvascular obstruction had large infarcts (>20% of the LV area). This infarct size is an important threshold because results of animal studies have indicated that LV remodeling occurs if more than 20% of the myocardium is affected by infarction (31). Therefore, detection of microvascular obstruction and accurate sizing of myocardial infarction are good indicators for identifying patients who are at risk for LV remodeling. Further studies are needed to analyze the relative abilities of microvascular obstruction and infarct size to predict LV remodeling and eventual outcome.
Microvascular Obstruction and Persistent Hypoenhancement
Presence of persistent hypoenhancement on DE MR images has been noted before (3,23), and it has been suggested that this finding may be related to a closed infarct-related artery (23). The data from our study show that persistent hypoenhancement occurs in the presence of an open epicardial vessel, because all patients underwent revascularization before imaging examinations were performed.
The high concordance between microvascular obstruction on FPE MR images and persistent hypoenhancement on DE MR images may suggest that DE MR images can be used for identification of microvascular obstruction. However, the sensitivity of DE MR images was only 74% for the detection of microvascular obstruction with FPE MR images used as the reference standard. In six (26%) of 23 patients with microvascular obstruction, no persistent hypoenhancement was present on DE MR images. This result is most likely related to the observed reduction in size of the areas of microvascular obstruction on FPE MR images compared with the size of areas of persistent hypoenhancement on DE MR images. The reduction in size of the hypoenhanced zone indicates that the edges of the perfusion defect are filled in over time by contrast material, through collateral flow or slow diffusion. Thus, FPE MR imaging preferably should be used for visualization of microvascular obstruction.
Limitations
In two patients, FPE MR imaging revealed no microvascular obstruction, but a persistent hypoenhancement was detected at DE MR imaging. This discordant finding was probably related to the fact that FPE MR imaging was performed in a single midventricular section, whereas DE MR imaging was performed in three sections. This limitation can be avoided with the acquisition of FPE MR images in multiple sections by using faster sequences and more rapid data acquisition strategies.
It has been shown that attenuation correction improves the homogeneity of tracer distribution on 201Tl SPECT images (30). However, this methodology is still being developed and evaluated, and no clinical evaluation study has produced results showing a significant improvement in sensitivity of SPECT with attenuation correction (32). Thus, attenuation correction was not performed in our study.
The software we used for 201Tl SPECT images (4D-MSPECT) compared our data to pooled data of healthy subjects. This analysis may have added a layer of manipulation to the SPECT data. A simple threshold analysis might have overcome some limitations of the analysis we performed. However, in a previous study of patients with acute myocardial infarction, results of a comparison of the use of the threshold method with that of the polar map method for measuring infarct size on 201Tl SPECT images revealed no differences (18). Furthermore, a recent study showed that a threshold analysis of SPECT images also missed a number of subendocardial infarcts similar to that in our study (29). Therefore, it is unlikely that a threshold analysis would have improved the diagnostic accuracy of SPECT imaging in our study.
For assessment of infarct size, fluorodeoxyglucose positron emission tomography (PET) may be a more suitable technique to compare with DE MR imaging in future studies, because PET images have fewer attenuation artifacts and scatter effects. Another possibility would be the use of necrosis-specific MR contrast media (7,9); however, these agents are not approved for human use. In patients with acute myocardial infarction, the lack of an accurate reference standard makes it difficult to verify the ability of imaging modalities to depict solely necrotic myocardium.
Clinical Implications
The good correlation and agreement between 201Tl SPECT and DE MR imaging indicate that DE MR imaging may be used to estimate various infarct sizes 6 days after reperfused acute myocardial infarction. Combined FPE and DE MR imaging may be useful for stratifying patients after acute myocardial infarction into a low-risk group, with no microvascular obstruction and small infarcts, and a high-risk group, with microvascular obstruction and large infarcts. However, besides infarct size and presence of microvascular obstruction, there are other parameters, such as LV ejection fraction, presence of inducible ischemia with exercise, or identification of reversible LV dysfunction, that have been used for risk stratification after acute myocardial infarction (33). Further studies have to be performed to demonstrate the importance and utility of the proposed MR imaging measurements to predict eventual outcome in a low-risk group of patients receiving reperfusion therapy, particularly in comparison with existing parameters.
|
APPENDIX |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSIONAPPENDIXREFERENCES |
|---|
|
FOOTNOTES |
|---|
Author contributions: Guarantors of integrity of entire study, G.K.L., M.S., G.A., T.M.; study concepts, G.K.L., M.S., C.B.H.; study design, G.K.L., A.S., M.S., J.M.; literature research, G.K.L., A.S.; clinical studies, G.K.L., A.S., M.P.B., J.H.G., V.M., J.M.; data acquisition and analysis/interpretation, G.K.L., A.S., M.P.B., J.H.G., V.M., J.M.; statistical analysis, G.K.L., A.S.; manuscript preparation and definition of intellectual content, G.K.L., A.S., M.S.; manuscript editing, G.K.L., M.S.; manuscript revision/review and final version approval, all authors
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTS DISCUSSIONAPPENDIXREFERENCES |
|---|
This article has been cited by other articles:
|
|
 |
|
  D. P. O'Regan, R. Ahmed, C. Neuwirth, Y. Tan, G. Durighel, J. V. Hajnal, I. Nadra, S. J. Corbett, and S. A. Cook Cardiac MRI of myocardial salvage at the peri-infarct border zones after primary coronary intervention Am J Physiol Heart Circ Physiol, July 1, 2009; 297(1): H340 - H346. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Carlsson, M. Wilson, A. J. Martin, and M. Saeed Myocardial Microinfarction after Coronary Microembolization in Swine: MR Imaging Characterization Radiology, March 1, 2009; 250(3): 703 - 713. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. P. O'Regan, R. Ahmed, N. Karunanithy, C. Neuwirth, Y. Tan, G. Durighel, J. V. Hajnal, I. Nadra, S. J. Corbett, and S. A. Cook Reperfusion Hemorrhage Following Acute Myocardial Infarction: Assessment with T2* Mapping and Effect on Measuring the Area at Risk Radiology, March 1, 2009; 250(3): 916 - 922. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Nijveldt, M. B. M. Hofman, A. Hirsch, A. M. Beek, V. A. W. M. Umans, P. R. Algra, J. J. Piek, and A. C. van Rossum Assessment of Microvascular Obstruction and Prediction of Short-term Remodeling after Acute Myocardial Infarction: Cardiac MR Imaging Study Radiology, February 1, 2009; 250(2): 363 - 370. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W P Bandettini and A E Arai Advances in clinical applications of cardiovascular magnetic resonance imaging Heart, November 1, 2008; 94(11): 1485 - 1495. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Nijveldt, A. M. Beek, A. Hirsch, M. G. Stoel, M. B.M. Hofman, V. A.W.M. Umans, P. R. Algra, J. W.R. Twisk, and A. C. van Rossum Functional recovery after acute myocardial infarction comparison between angiography, electrocardiography, and cardiovascular magnetic resonance measures of microvascular injury. J. Am. Coll. Cardiol., July 15, 2008; 52(3): 181 - 189. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 V. Pineda, X. Merino, S. Gispert, P. Mahia, B. Garcia, and R. Dominguez-Oronoz No-Reflow Phenomenon in Cardiac MRI: Diagnosis and Clinical Implications Am. J. Roentgenol., July 1, 2008; 191(1): 73 - 79. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. E. Rochitte Microvascular obstruction the final frontier for a complete myocardial reperfusion. J. Am. Coll. Cardiol., June 10, 2008; 51(23): 2239 - 2240. [Full Text] [PDF]
|
|
|
|
|
|
G. K. Lund, A. Stork, K. Muellerleile, A. A. Barmeyer, M. P. Bansmann, M. Knefel, U. Schlichting, M. Muller, P. E. Verde, G. Adam, et al. Prediction of Left Ventricular Remodeling and Analysis of Infarct Resorption in Patients with Reperfused Myocardial Infarcts by Using Contrast-enhanced MR Imaging Radiology, October 1, 2007; 245(1): 95 - 102. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Saeed, D. Saloner, A. Martin, L. Do, O. Weber, P. C. Ursell, A. Jacquier, R. Lee, and C. B. Higgins Adeno-associated Viral Vector-Encoding Vascular Endothelial Growth Factor Gene: Effect on Cardiovascular MR Perfusion and Infarct Resorption Measurements in Swine Radiology, May 1, 2007; 243(2): 451 - 460. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Ibrahim, H. P. Bulow, T. Hackl, M. Hornke, S. G. Nekolla, M. Breuer, A. Schomig, and M. Schwaiger Diagnostic Value of Contrast-Enhanced Magnetic Resonance Imaging and Single-Photon Emission Computed Tomography for Detection of Myocardial Necrosis Early After Acute Myocardial Infarction J. Am. Coll. Cardiol., January 16, 2007; 49(2): 208 - 216. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Saeed, O. Weber, R. Lee, L. Do, A. Martin, D. Saloner, P. Ursell, P. Robert, C. Corot, and C. B. Higgins Discrimination of Myocardial Acute and Chronic (Scar) Infarctions on Delayed Contrast Enhanced Magnetic Resonance Imaging With Intravascular Magnetic Resonance Contrast Media J. Am. Coll. Cardiol., November 21, 2006; 48(10): 1961 - 1968. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. P. Finn, R. Saleh, S. Thesen, S. G. Ruehm, M. H. Lee, J. Grinstead, J. S. Child, and G. Laub MR Imaging with Remote Control: Feasibility Study in Cardiovascular Disease Radiology, November 1, 2006; 241(2): 528 - 537. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. T. Yan, A. J. Shayne, K. A. Brown, S. N. Gupta, C. W. Chan, T. M. Luu, M. F. Di Carli, H. G. Reynolds, W. G. Stevenson, and R. Y. Kwong Characterization of the Peri-Infarct Zone by Contrast-Enhanced Cardiac Magnetic Resonance Imaging Is a Powerful Predictor of Post-Myocardial Infarction Mortality Circulation, July 4, 2006; 114(1): 32 - 39. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. J. van den Bos, T. Baks, A. D. Moelker, W. Kerver, R.-J. van Geuns, W. J. van der Giessen, D. J. Duncker, and P. A. Wielopolski Magnetic resonance imaging of haemorrhage within reperfused myocardial infarcts: possible interference with iron oxide-labelled cell tracking? Eur. Heart J., July 1, 2006; 27(13): 1620 - 1626. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. P. Meyer, K. C. Wollert, J. Lotz, J. Steffens, P. Lippolt, S. Fichtner, H. Hecker, A. Schaefer, L. Arseniev, B. Hertenstein, et al. Intracoronary Bone Marrow Cell Transfer After Myocardial Infarction: Eighteen Months' Follow-Up Data From the Randomized, Controlled BOOST (BOne marrOw transfer to enhance ST-elevation infarct regeneration) Trial Circulation, March 14, 2006; 113(10): 1287 - 1294. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Tarantini, L. Cacciavillani, F. Corbetti, A. Ramondo, M. P. Marra, E. Bacchiega, M. Napodano, C. Bilato, R. Razzolini, and S. Iliceto Duration of Ischemia Is a Major Determinant of Transmurality and Severe Microvascular Obstruction After Primary Angioplasty: A Study Performed With Contrast-Enhanced Magnetic Resonance J. Am. Coll. Cardiol., October 4, 2005; 46(7): 1229 - 1235. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. J. Gibbons and P. A. Araoz The Year in Cardiac Imaging J. Am. Coll. Cardiol., August 2, 2005; 46(3): 542 - 551. [Full Text] [PDF]
|
|
|
|
 |
|
 P. J. Slomka, D. Fieno, L. Thomson, J. D. Friedman, S. W. Hayes, G. Germano, and D. S. Berman Automatic Detection and Size Quantification of Infarcts by Myocardial Perfusion SPECT: Clinical Validation by Delayed-Enhancement MRI J. Nucl. Med., May 1, 2005; 46(5): 728 - 735. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. Hombach, O. Grebe, N. Merkle, S. Waldenmaier, M. Hoher, M. Kochs, J. Wohrle, and H. A. Kestler Sequelae of acute myocardial infarction regarding cardiac structure and function and their prognostic significance as assessed by magnetic resonance imaging Eur. Heart J., March 2, 2005; 26(6): 549 - 557. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| RADIOLOGY | RADIOGRAPHICS | RSNA JOURNALS ONLINE |
), and P < .001 for size of microvascular obstruction versus infarct size on DE MR images in patients with microvascular obstruction (
).