Iacopo Carbone MD, Presenter: Nothing to Disclose

Helene Childs, Abstract Co-Author: Nothing to Disclose

Ahmed Alijizeeri, Abstract Co-Author: Nothing to Disclose

Ingo Eitel, Abstract Co-Author: Nothing to Disclose

Naeem Merchant MD, Abstract Co-Author: Nothing to Disclose

Matthias G. Friedrich, Abstract Co-Author: Nothing to Disclose

Accurate analysis of T2-weighted MRI is crucial for myocardial edema (ME) assessment. In view of frequent artifacts from motion, slow flow, and field inhomogenities affecting infarcted and remote myocardium (ReM), several approaches can be used to evaluate ME: 1) visual assessment, 2) signal intensity (SI) > 2 SDs of ReM or 3) normalizing myocardial SI to that of a skeletal muscle: T2 SI Ratio. Currently, there is no standardized approach for quantitative edema assessment using T2-weighted imaging. In late-reperfused myocardial infarction (MI) the infarct size (IS) usually matches edema size. The purpose of our study was to compare different approaches for the analysis of T2-weighted images in late-reperfused MI using late gadolinium enhancement (LGE) as a reference standard.

Thirty patients with acute late-reperfused MI (time to reperfusion>200min) who underwent cardiac MRI at 1.5 T ≤5 days from symptom onset were retrospectively studied. MRI protocol: b-SSFP cine, T2-STIR imaging using a body coil and LGE imaging. 10 patients demonstrated microvascular obstruction (MO) on LGE images and were analyzed separately. IS was determined on LGE images using a threshold of 5SD above the SI of ReM. T2 images were analyzed using thresholds of 2, 3 and 5SD above the SI of ReM, as well as using T2 SI Ratio.

There was a good agreement between LGE 5SD and T2 SI Ratio in patients without MO (r=0.826) and with MO (r=0.996). In patients without MO IS was not correlated with edema size using thresholds of T2 at 2SD, 3SD and at 5SD (r=0.511, r=0.530, and r=0.265 respectively). In patients with MO there was a correlation between all LGE at 5SD and T2 at 2, 3 and 5 SD measurements.

T2 SI Ratio appears to be the most reproducible and precise approach for the evaluation of the size of ME.

A standardized method for the quantification of myocardial edema is extremely useful especially in diffuse process when its recognition could be difficult by the naked eye.

Carbone, I, Childs, H, Alijizeeri, A, Eitel, I, Merchant, N, Friedrich, M, Which Is the Most Reproducible Method for the Quantitative Assessment of Regional Myocardial Edema?.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11016358.html