Author + information
- Ron Blankstein, MD∗ (, )
- Michael T. Osborne, MD,
- Sharmila Dorbala, MD, MPH and
- Marcelo F. Di Carli, MD
- ↵∗Cardiovascular Division and Department of Radiology, Brigham and Women's Hospital, 75 Francis Street, Room Shapiro 5096, Boston, Massachusetts 02115
We thank Dr. Eguchi and colleagues you for their interest in our paper (1). Our study was not designed to evaluate the effect of treatment on the positron emission tomography (PET)/computed tomography (CT) results. For patients who had multiple PET/CT scans, we only included the initial scan results. Nevertheless, during the baseline PET/CT study, 26% of the patients were treated with corticosteroids. Although we agree that treatment can reduce inflammation, such an effect would only minimize the association identified in our study; thus, if no steroids were used at baseline, the differences in outcomes between the groups may be even larger. We agree that PET can be useful for assessing the response to therapy, and our group recently showed that a reduction in the amount of inflammation, as assessed by using serial PET/CT studies, is associated with improved left ventricular ejection fraction (2).
When we used the updated (2006) Japanese guidelines, significant discordance remained between these criteria and the PET/CT results. Implantable cardioverter-defibrillator implantations were performed at the discretion of the treating physicians for both primary and secondary prevention of sudden cardiac death.
Our laboratory and others have used a fast of at least 3 h after a high-fat, low-carbohydrate diet. In considering the validity of this approach, we would note that our rate of diffuse F-18 fluorodeoxyglucose uptake is low and similar to that reported by others (3). Our center has used various diets (including a longer period of fasting), and we have detected no significant differences in suppression of F-18 fluorodeoxyglucose from the normal myocardium with these different approaches.
With regard to the higher yield of endomyocardial biopsy among patients with abnormal PET/CT results, we believe that patients with positive imaging findings are more likely to have significant disease and, therefore, are more likely to have positive biopsy results. Although image-guided biopsy may improve the diagnostic yield, it is essential for clinicians to know that the sensitivity of endomyocardial biopsy is extremely low. Therefore, it is not uncommon for patients with negative results on endomyocardial biopsy to have cardiac involvement.
- American College of Cardiology Foundation