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Serial assessment of myocardial infarction by using gated MR imaging and Gd-DTPA
T Nishimura1, H Kobayashi, Y Ohara
1Department of Radiology, National Cardiovascular Center, Osaka, Japan.
Abstract:
In order to assess the usefulness of Gd-DTPA in the evaluation of myocardial infarction, 17 patients were examined with gated MR imaging. Scans were made by using a spin-echo pulse sequence before and after IV administration of 0.15 mmol/kg of Gd-DTPA. The images were made at four intervals (average of 5, 12, 30, and 90 days) after the onset of the infarction. Gd-DTPA uptake at the infarcted area was graded as marked, moderate, or no increase in signal intensity by visual inspection. At these four time intervals, an area of increased signal intensity in the infarcted myocardium was detected on T1-weighted images after administration of Gd-DTPA in 14 (82%) of 17 cases, 16 (94%) of 17 cases, six (38%) of 16 cases, and three (21%) of 14 cases, respectively. Markedly increased signal intensity in infarcted areas was shown on T1-weighted images with Gd-DTPA at 5 and 12 days. The ratio of gadolinium uptake in the infarcted area to that in normal myocardium also was evaluated. At 5 and 12 days, the mean increase in signal intensity in the infarcted area was significantly higher than that in a normal area, but not at 30 and 90 days. Increased signal intensity also was apparent on T2-weighted images without Gd-DTPA at 5 and 12 days; however, the use of late echo reduced the signal-to-noise ratio, leading to image degradation. Uptake of Gd-DTPA was a positive marker in acute myocardial infarction, but no significant uptake of Gd-DTPA occurred in chronic myocardial infarction.
Insights
Gadolinium-DTPA (Gd-DTPA) enhances MRI detection of acute myocardial infarction by increasing signal intensity in damaged heart muscle. Its effectiveness diminishes in chronic cases, making it a valuable tool for early diagnosis.
Area of Science:
- Cardiovascular Imaging
- Radiology
- Medical Diagnostics
Background:
- Myocardial infarction (MI) diagnosis relies on imaging techniques.
- Gadolinium-based contrast agents like Gd-DTPA can improve MRI sensitivity.
- Assessing the temporal utility of Gd-DTPA in MI evaluation is crucial.
Purpose of the Study:
- To evaluate the diagnostic usefulness of Gd-DTPA in assessing myocardial infarction (MI).
- To determine the optimal timing for Gd-DTPA administration in MI detection using MRI.
Main Methods:
- Seventeen patients with MI underwent gated MRI scans.
- Spin-echo pulse sequences were used before and after IV Gd-DTPA administration.
- Images were acquired at 5, 12, 30, and 90 days post-infarction.
Main Results:
- Gd-DTPA enhanced signal intensity in infarcted myocardium in 82% (5 days) and 94% (12 days) of cases.
- Markedly increased signal intensity was observed at 5 and 12 days post-MI.
- Significant gadolinium uptake ratio in infarcted vs. normal myocardium was noted at 5 and 12 days, but not later.
- Gd-DTPA uptake was a positive marker for acute MI, but not for chronic MI.
Conclusions:
- Gd-DTPA is a valuable contrast agent for detecting acute myocardial infarction via MRI.
- The diagnostic utility of Gd-DTPA diminishes significantly in chronic myocardial infarction.
- MRI with Gd-DTPA shows greatest efficacy in the early stages of myocardial infarction.