Comments on: Acute Myocardial Infarction: Serial Cardiac MR Imaging Shows a Decrease in Delayed Enhancement of the Myocardium During the 1st Week After Reperfusion http://www.thepreparedminds.com/archives/894 In the field of observation, chance favors the prepared minds. Sat, 04 Feb 2012 14:45:45 +0000 hourly 1 http://wordpress.org/?v=3.3 By: Cleveland Clinic Florida Journal Club http://www.thepreparedminds.com/archives/894/comment-page-1#comment-945 Cleveland Clinic Florida Journal Club Wed, 03 Feb 2010 03:17:08 +0000 http://www.thepreparedminds.com/?p=894#comment-945 The authors evaluate the changes of delayed enhancement of infarcted myocardium by using serial MR examinations in a cohort of 17 patients. This is a relevant study clinically that sheds light into the pathophysiology of the early re-vascularized state. The estimation of the infarct size after coronary reperfusion is increasingly being used as a surrogate endpoint of how effective the reperfusion was. In the early stages after a myocardial infarction (first 48 hours) delayed enhancement of infarcted myocardium by using cardiac MRI may overestimate the infarct size, mainly due to the cellular changes that occur within the myocardium early after an event. Based on the myocardial enhancement images on the serial cardiac MR examinations of this cohort of 17 patients, the infarct size findings remained stable after day 7. Based on this, we would be able to determine the final infarct expansion only a week after a coronary event. This could have important implications towards the identification of patients who could potentially benefit from additional interventions such as device therapy early after a myocardial infarction (< 40 days). Some of the comments made during our discussion included: - While the significant change in the size of the area of persistent enhancement demonstrated at day 1 and day 7 may represent a change in infarct size (or a decrease in peri-infarct edema), this could have been further investigated by using heavily T2 weighted images to assess the myocardial edema and its changes. - We found very interesting that there is no mention of the obtention of first pass perfusion sequences, as they may better correlate with the areas of late enhancement as seen on the studies obtained later in time. - A recent post in this website (http://www.thepreparedminds.com/archives/614) compared an early late enhancement sequence obtained at 2 minutes after administration of the gadolinium chelate with a conventional late sequence obtained at 10 minutes and showed that the extent of extent of MVO decreased from early to late imaging. It would've been very interesting to see a similar approach in this group of patients, which could've explained their 1 case of resolved MVO. The authors evaluate the changes of delayed enhancement of infarcted myocardium by using serial MR examinations in a cohort of 17 patients. This is a relevant study clinically that sheds light into the pathophysiology of the early re-vascularized state.

The estimation of the infarct size after coronary reperfusion is increasingly being used as a surrogate endpoint of how effective the reperfusion was.

In the early stages after a myocardial infarction (first 48 hours) delayed enhancement of infarcted myocardium by using cardiac MRI may overestimate the infarct size, mainly due to the cellular changes that occur within the myocardium early after an event.

Based on the myocardial enhancement images on the serial cardiac MR examinations of this cohort of 17 patients, the infarct size findings remained stable after day 7. Based on this, we would be able to determine the final infarct expansion only a week after a coronary event. This could have important implications towards the identification of patients who could potentially benefit from additional interventions such as device therapy early after a myocardial infarction (< 40 days).

Some of the comments made during our discussion included:

- While the significant change in the size of the area of persistent enhancement demonstrated at day 1 and day 7 may represent a change in infarct size (or a decrease in peri-infarct edema), this could have been further investigated by using heavily T2 weighted images to assess the myocardial edema and its changes.

- We found very interesting that there is no mention of the obtention of first pass perfusion sequences, as they may better correlate with the areas of late enhancement as seen on the studies obtained later in time.

- A recent post in this website (http://www.thepreparedminds.com/archives/614) compared an early late enhancement sequence obtained at 2 minutes after administration of the gadolinium chelate with a conventional late sequence obtained at 10 minutes and showed that the extent of extent of MVO decreased from early to late imaging. It would’ve been very interesting to see a similar approach in this group of patients, which could’ve explained their 1 case of resolved MVO.

]]> By: Paul Schoenhagen, MD http://www.thepreparedminds.com/archives/894/comment-page-1#comment-644 Paul Schoenhagen, MD Mon, 28 Dec 2009 04:00:45 +0000 http://www.thepreparedminds.com/?p=894#comment-644 It is important to consider the implications, of the results for scenarios where the decision for surgical revascularization is based on delayed MRI imaging. As described on page 92* and shown in table 3*; in particular the transmural extent of scar changed in the first 7 days. *To view, you must have online access/hard copy of Radiology Journal It is important to consider the implications, of the results for scenarios where the decision for surgical revascularization is based on delayed MRI imaging.
As described on page 92* and shown in table 3*; in particular the transmural extent of scar changed in the first 7 days.
*To view, you must have online access/hard copy of Radiology Journal

]]> By: Jacobo Kirsch, MD http://www.thepreparedminds.com/archives/894/comment-page-1#comment-631 Jacobo Kirsch, MD Sat, 26 Dec 2009 00:45:45 +0000 http://www.thepreparedminds.com/?p=894#comment-631 Very interesting findings! I personally favor the authors comments in the discussion that point that delayed gadolinium enhancement within ischemically injured myocardium is related to an increase in interstitial space and owing to the nonspecific properties of gadolinium-based contrast agents this may overestimate the true infarct size when MR is performed soon after reperfusion. A recent <a href="http://www.thepreparedminds.com/archives/614" rel="nofollow">paper</a>, also showed that DE-MRI overestimates when compared to First Pass perfusion imaging. It would've been very interesting to see if in this group of patients, the area of scar after 7 days correlated with the First Pass perfusion defect. Very interesting findings! I personally favor the authors comments in the discussion that point that delayed gadolinium enhancement within ischemically injured myocardium is related to an increase in interstitial space and owing to the nonspecific properties of gadolinium-based contrast agents this may overestimate the true infarct size when MR is performed soon after reperfusion.
A recent paper, also showed that DE-MRI overestimates when compared to First Pass perfusion imaging. It would’ve been very interesting to see if in this group of patients, the area of scar after 7 days correlated with the First Pass perfusion defect.

]]> By: Phillip M. Young, MD http://www.thepreparedminds.com/archives/894/comment-page-1#comment-619 Phillip M. Young, MD Thu, 24 Dec 2009 20:11:37 +0000 http://www.thepreparedminds.com/?p=894#comment-619 Very nice study, following patients after PCI and stent placement in the setting of acute MI. This work corresponds with previous work suggesting that delayed enhancement decreases in the first week following infarction. It is also interesting that they find little change in delayed enhancement after the first week. The study suggests that when using myocardial delayed enhancement as a measure of response to therapy, one should consider the timing of the examination with respect to the initial event. It also makes clear how little we really know about the physiology underlying myocardial delayed enhancement. Very nice study, following patients after PCI and stent placement in the setting of acute MI. This work corresponds with previous work suggesting that delayed enhancement decreases in the first week following infarction. It is also interesting that they find little change in delayed enhancement after the first week. The study suggests that when using myocardial delayed enhancement as a measure of response to therapy, one should consider the timing of the examination with respect to the initial event. It also makes clear how little we really know about the physiology underlying myocardial delayed enhancement.

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