Clinical Investigation
Imaging and Diagnostic Testing
Identification and viability assessment of infarcted myocardium with late enhancement multidetector computed tomography: Comparison with thallium single photon emission computed tomography and echocardiography

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Background

Recent studies revealed that multidetector computed tomography late enhancement (MDCT-LE) is a reliable technique for detecting necrotic and scarred myocardial tissue. The aims of the study were to identify infarcted myocardium using MDCT-LE protocol in patients after myocardial infarction (MI) and assess viability in resting wall motion abnormalities.

Methods

One hundred one patients with previous MI (62 ± 13 years, 1-6 months after MI) underwent MDCT-LE (15 minutes after contrast medium administration), rest-redistribution thallium single photon emission computed tomography (Tl-SPECT), and dobutamine echocardiography (DbE). In a 17-segment model, infarcted myocardium detected by MDCT-LE was categorized as none, 1%-25%, 26%-50%, 51%-75%, or >75% segmental extent and was compared with decreased uptake of Tl-SPECT and contractile function by DbE on per patient and segmental basis in a blinded fashion.

Results

By per patient analysis, MDCT-LE identified the presence of infarcted myocardium in 97 patients (96%), and Tl-SPECT decreased uptake in 88 patients (87%), (P = .02). By per segment analysis, the concordance for detecting infarcted myocardium was good (κ value = 0.792). In segments with resting wall motion abnormalities (N = 486), there was moderate concordance in assessing viability (κ value between MDCT and Tl-SPECT = 0.555, MDCT and DbE = 0.498, Tl-SPECT and DbE = 0.478) with predefined MDCT-LE threshold of 50% segmental extent. Among segments with MDCT-LE >75% segmental extent, the proportion designated nonviable by Tl-SPECT and DbE reached 87.8% and 92.2%, respectively.

Conclusions

Multidetector computed tomography late enhancement is accurate in identifying the presence and extent of infarcted myocardium. Its segmental extent has good correlation with the magnitude of thallium decreased uptake and can predict contractile reserve. Multidetector computed tomography late enhancement can be an alternative to assess viability.

Section snippets

Study patients

From January to December 2006, 155 patients referred to our cardiovascular center who had documented history of MI (>1 months and ≤6 months), did not receive primary or rescue angioplasty, and did not have valvular disease of more than moderate severity were evaluated to participate in this prospective study. Diagnosis of MI was defined by typical anginal pain lasting ≥30 minutes, biochemical evidence of peak creatine kinase ≥2 times of upper limit of normal with typical upsloping and

Clinical characteristics

During the period of the study, 116 patients who fit MDCT inclusion criteria underwent investigation. Fifteen patients were excluded because of image quality reasons (7 patients for MDCT images because of respiratory motion artifacts and 8 patients for DbE images because of limited echocardiographic windows with attenuation artifacts). Therefore, a total of 101 patients completed the study and further image analysis. All patients had MDCT-LE, Tl-SPECT, and DbE performed within 1 week after a

Discussion

This study shows that MDCT-LE can be accurate to identify the presence, location, and extent of infarcted myocardium and predict viability in selected patients after MI. From our enrolled patients with recent to chronic MI, approximately 75% fit MDCT inclusion criteria. Patient selection should be considered before applying this technique.

Conclusions

Multidetector computed tomography is accurate to identify the presence, location, and extent of infarcted myocardium, in comparison with Tl-SPECT and DbE. The segmental extent of MDCT-LE has good correlation with the magnitude of Tl-201 decreased uptake and can predict contractive reserve. It can serve as an alternative approach to assess viability, especially in selected patients with MI and LV dysfunction.

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This study was supported by the National Science Council, Taiwan (NSC 95-2314-B-075B-010-MY2, NSC 95-2314-B-010-100-MY2, NSC 95-2314-B-0758B-004) and Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan (VGHKS 95-002&-003).

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