Related Experiment Videos
[Diagnosis of left ventricular aneurysm by exercise thallium-201 myocardial single photon emission computed
M Okano1, F Ohsuzu, S Katsushika
1First Department of Internal Medicine, National Defense Medical College, Tokorozawa.
Insights
Exercise thallium-201 myocardial single photon emission computed tomography (SPECT) can diagnose left ventricular aneurysms. This imaging technique effectively identifies extensive apicoanterior infarction and divergent wall arrangements, crucial for predicting prognosis.
Area of Science:
- Cardiology
- Nuclear Medicine
- Medical Imaging
Background:
- Left ventricular aneurysms (LVAs) are serious complications following myocardial infarction (MI).
- Accurate diagnosis and characterization of LVAs are crucial for predicting patient prognosis.
- Current diagnostic methods may require invasive procedures.
Observation:
- This study utilized exercise thallium-201 myocardial single photon emission computed tomography (SPECT) in 79 post-MI patients.
- Ventricular wall morphology was classified into convergent, parallel, and divergent types based on SPECT imaging.
- A high incidence of LVAs was observed in patients with a divergent-type wall arrangement (Group E).
Findings:
- Exercise SPECT demonstrated high diagnostic sensitivity (89-96%), specificity (75-92%), and accuracy (86%) for LVA detection.
- LVAs were strongly associated with extensive apicoanterior infarction and a divergent ventricular wall morphology on post-stress SPECT.
- Larger defect scores on polar maps correlated with the presence of LVAs.
Implications:
- Exercise SPECT can reliably diagnose LVAs, potentially reducing the need for more invasive tests.
- Identifying specific imaging patterns (apicoanterior infarction, divergent morphology) aids in LVA characterization.
- This non-invasive approach offers valuable prognostic information for post-MI patients.
Abstract:
To diagnose and characterize post-infarction left ventricular aneurysms, we performed exercise thallium-201 myocardial single photon emission computed tomography (SPECT) combined with selective coronary angiography and left ventriculography. The subjects consisted of 79 patients with acute myocardial infarction; 42 with anteroseptal, three with both anterior and inferior, 29 with inferior and five with posterior infarction. Visual classification of ventricular wall morphology by either a horizontal or a vertical long-axis image was designed into convergent (C), parallel (P) and divergent (D) types, according to the interrelationship between either septal and lateral wall or anterior and inferior wall, respectively. This method was applied in post-stress and delayed images, and these patients were divided into five groups (Group A-E) in accordance with varying morphological types from the post-stress to the delayed as follows: C-C (Group A, 36 patients), P-C (Group B, 8), P-P (Group C, 7), D-P (Group D, 5) and D-D (Group E, 23). A high incidence (21/23) of a left ventricular aneurysm by left ventriculography was recognized in Group E patients in comparison with other Groups. Provided that either Group D or E (all patients had anterior infarction) had left ventricular aneurysms, the diagnostic sensitivity, specificity and accuracy were 89%, 92% and 86%, respectively. Two of three patients with false negative diagnosis had only apical involvement. Furthermore, these two Groups had significantly larger defect scores as calculated by polar maps than did the other three Groups. When patients with anterior infarction with defect scores of 200 or greater were defined positive, the sensitivity, specificity and accuracy of ventricular aneurysms were 96%, 75% and 86%, respectively. One false negative case was apical infarction, and one of the two false positive cases were extensive anteroseptal infarction involving the apex. These results suggest that a left ventricular aneurysm which is important in predicting prognostic sequence could be diagnosed only by exercise SPECT, and that it could be characterized by extensive and severe apicoanterior infarction and a divergent-type ventricular wall arrangement on a post-stress SPECT image.