Potential utility of SPECT/CT with 99mTc-Tektrotyd for imaging of post-myocardial infarction inflammation.

Background: There is a need to develop methods for post-myocardial infarction (MI) inflammation monitoring. Scintigraphy with somatostatin receptor targeted radiotracers has potential in this field. The purpose was to study the association of Tc-Tektrotyd uptake intensity in MI area with heart contractility indices over 6-month follow-up.

Methods: Fourteen patients with acute ST-segment elevation anterior MI (STEMI) were examined with Tc-Tektrotyd SPECT/CT, myocardial perfusion scintigraphy (MPS) at rest, cardiac magnetic resonance imaging (cMRI) and transthoracic echocardiography (TTE). Scintigraphic results were compared with 6-month TTE indices.

Results: On the 7th day after a MI onset, cardiac Tc-Tektrotyd uptake was found in 7 of 14 patients. Median of Tc-Tektrotyd SUVmax was 1.59 (1.38; 2.83), the summed rest score (SRS) was 11 (5; 18), infarct size (by cMRI)-13.15 (3.3; 32.2) %. Tc-Tektrotyd SUVmax strongly correlated with 6-month heart contractility indices (r = 0.81, P < 0.05 for the end diastolic volume; r = 0.61 P < 0.05 for Δ end diastolic volume), with SRS (r = 0.85, P < 0.05) and infarct size (by cMRI) (r = 0.79, P < 0.05).

Conclusion: The intensity (SUVmax) of Tc-Tektrotyd uptake in the area of recent MI directly depends on the size of ischemic myocardial injury and correlates with changes of heart contractility indexes over the 6 month follow-up.