[Thallium single photon emission computed tomography following thrombolysis: missing relation to left ventricular...

Area of Science:

• Cardiology
• Nuclear Medicine
• Radiology

Background:

• Assessing myocardial infarct size after thrombolysis is crucial for evaluating treatment efficacy.
• Thallium-201 single-photon emission computed tomography (SPECT) scintigraphy and contrast cineangiography are imaging modalities used to assess cardiac function and infarct size.

Purpose of the Study:

• To compare the estimation of infarct size using thallium SPECT scintigraphy and contrast cineangiography after thrombolysis.
• To investigate the correlation between regional wall motion abnormalities and infarct size determined by SPECT.

Main Methods:

• 32 patients with regional wall motion abnormalities post-myocardial infarction underwent biphasic thallium SPECT scintigraphy with dipyridamole 10-21 days after infarction.
• Regional wall motion abnormality was assessed using the 'centerline' method.
• Statistical analysis was performed to correlate left ventricular ejection fraction, hypokinesia, thallium defect size, and time to reperfusion.

Main Results:

• No significant correlation was found between left ventricular ejection fraction or degree of hypokinesia and thallium defect size.
• Hypokinesia was inversely correlated with the time interval from symptom onset to reperfusion (r = -0.51).
• Thallium defect size did not differ between patients with early (<3h) versus late reperfusion, although hypokinesia was significantly less in the early reperfusion group.

Conclusions:

• There is no close correlation between subacute regional wall motion abnormalities and chronic infarct size determined by SPECT after thrombolysis.
• Left ventricular function impairment may not be accurately assessed from chronic-state scintigraphic findings post-thrombolysis.