Kai-Uwe U Waltering MD, Presenter: Nothing to Disclose

Thomas Schlosser MD, PhD, Abstract Co-Author: Nothing to Disclose

Kai Nassenstein, Abstract Co-Author: Nothing to Disclose

Oliver Bruder, Abstract Co-Author: Nothing to Disclose

Peter Hunold MD, Abstract Co-Author: Nothing to Disclose

Joerg Barkhausen MD, Abstract Co-Author: Nothing to Disclose

To measure T1 values of normal and infarcted myocardium before and after contrast injection using inversion recovery prepared steady state free precession sequences (IR-SSFP).

38 patients (30 male, 8 female, mean age 56.0±13.0 years) with first acute ST-elevation myocardial infarction were enrolled into the study. MR imaging was performed on a 1.5T MR-system within 2.9±1.9 days after infarction. T1 values of non-infarcted myocardium and infarcted myocardium were estimated using a steady state free precession sequence (TR 2.5 ms, TE 1.1 ms, FA 50°) with incrementally increased inversion times acquired during a single breath-hold. Long axis views covering the area of the infarction were collected before and 1, 3, 5, 10, 15, 20 and 25 minutes after Gadodiamide injection (0.2 mmol/kg BW, Omniscan, Amersham). T1 values were obtained using the following equation: T1 = TI(min)/ln2, where TI(min) is the inversion time of the image with the minimum signal intensity of the tissue. T1 values were calculated for normal myocardium, the area of delayed enhancement (DE) and the no-reflow zone.

The T1 times of normal myocardium and the area of delayed enhancement showed no significant differences within the first three minutes after contrast injection. Thereafter, the DE area showed significant shorter T1 values with a maximum difference 15 minutes after contrast (DE: 264±38ms; normal myocardium: 354±33ms). The maximum difference between the no-reflow zone and the surrounding tissues was found immediately after contrast administration (no-reflow: T1=347±167ms, normal myocardium T1=206±41ms, DE T1=211±86ms).

Our data show, that the highest contrast between the no-reflow zone and the surrounding tissue can be obtained immediately after contrast administration, whereas the maximum contrast between normal and infarcted myocardium requires a delay of 15 minutes. Therefore measurements of the no-reflow zone should be performed immediately after contrast injection, whereas the area of DE should be assessed about 15 minutes after contrast injection.

Waltering, K, Schlosser, T, Nassenstein, K, Bruder, O, Hunold, P, Barkhausen, J, Contrast-enhanced Magnetic Resonance Imaging of Acute Myocardial Infarction: Optimization of Image Contrast.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4415138.html