August 1, 2006Radiology52 citations
Does Myocardial Fibrosis Hinder Contractile Function and Perfusion in Idiopathic Dilated Cardiomyopathy? PET and MR Imaging Study
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Key Result
In patients with idiopathic DCM, the extent of myocardial fibrosis (PTI) was significantly correlated with impaired contractile function (Ecc) (r = -0.21, P = .009), but not with myocardial perfusion.
Key Points
- This study aims to evaluate the relationship between myocardial fibrosis, perfusion, and contractile function in patients with idiopathic dilated cardiomyopathy using advanced imaging techniques.
- Prospective evaluation of 16 patients with idiopathic DCM and 6 healthy controls using PET and MR imaging.
- Assessment of myocardial blood flow at rest and during induced hyperemia using carbon monoxide and oxygen 15-labeled water as tracers.
- Determination of maximum circumferential shortening via MR tissue tagging.
- Mean global hyperemic myocardial blood flow (2.23 vs 4.33 mL/min/mL, P < .05) and maximum circumferential shortening (-10.5% vs -17.4%, P < .05) were significantly lower in DCM patients.
- Regional perfusable tissue index was correlated with contractile function (E(cc)) but not with blood flow parameters.
- Right and global hyperemic myocardial perfusion metrics showed significant association with both contractility and end-diastolic wall stress metrics.
Study Design
Type
Observational (n=22)
Structured PICO
Do myocardial fibrosis, perfusion, and contractile function interrelate in patients with idiopathic dilated cardiomyopathy?
P
Population
16 patients with idiopathic dilated cardiomyopathy (DCM) (mean age 54 +/- 11 years, 9 men) and 6 healthy control subjects (mean age 28 +/- 2 years, 5 men).
I
Intervention
Positron emission tomography (PET) with Oxygen 15-labeled water and carbon monoxide, and magnetic resonance (MR) tissue tagging.
C
Comparator
Healthy control subjects.
O
Outcome
Interrelationships between regional myocardial fibrosis (assessed by perfusable tissue index [PTI]), perfusion (myocardial blood flow [MBF]), and contractile function (maximum circumferential shortening [Ecc]).surrogate
In idiopathic dilated cardiomyopathy, myocardial fibrosis correlates with impaired contractile function but not with perfusion, whereas impaired hyperemic perfusion correlates with contractility and end-diastolic wall stress.
Main Result
Effect estimate: r = -0.21
p-value: p=0.009
Abstract
PURPOSE: To prospectively evaluate, by using positron emission tomography (PET) and magnetic resonance (MR) imaging, the interrelationships between regional myocardial fibrosis, perfusion, and contractile function in patients with idiopathic dilated cardiomyopathy (DCM). MATERIALS AND METHODS: The study protocol was approved by the hospital ethics committee, and all subjects gave written informed consent. Sixteen patients with idiopathic DCM (mean age, 54 years +/- 11 standard deviation; nine men) and six healthy control subjects (mean age, 28 years +/- 2; five men) were examined with PET and MR tissue tagging. Oxygen 15-labeled water and carbon monoxide were used as tracers at PET to assess myocardial blood flow (MBF) and the perfusable tissue index (PTI), which is inversely related to fibrosis. MBF was determined at rest and during pharmacologically induced hyperemia. Maximum circumferential shortening (E(cc)) was determined with MR tissue tagging. Student t tests were performed for comparison of data sets, and linear regression was used to investigate the association between parameters. RESULTS: Mean global hyperemic MBF (2.23 mL/min/mL +/- 0.73), E(cc) (-10.5% +/- 2.9), and PTI (0.95 +/- 0.10) were lower in the patients with DCM than in the control subjects (4.33 mL/min/mL +/- 0.85, -17.4% +/- 0.6, and 1.09 +/- 0.12, respectively; P < .05 for all). In the patients with DCM, regional PTI was related to E(cc) (r = -0.21, P = .009) but not to resting or hyperemic MBF. Furthermore, regional E(cc) was correlated to both resting (r = -0.28, P = .004) and hyperemic MBF (r = -0.29, P < .001). In addition, the ratio of left ventricular end-diastolic volume to mass, as a reflection of wall stress, was related to global hyperemic MBF (r = -0.52, P = .047) and to global E(cc) (r = 0.69, P = .003). CONCLUSION: In idiopathic DCM, the extent of myocardial fibrosis is related to the impairment in contractile function, whereas fibrosis and perfusion do not seem to be interrelated. The degree of impairment of hyperemic myocardial perfusion is related to contractility and end-diastolic wall stress.
Cite This Study
Knaapen et al. (2006) conducted an observational in Idiopathic dilated cardiomyopathy (DCM) (n=22). Positron emission tomography (PET) and magnetic resonance (MR) imaging vs. Healthy control subjects was evaluated on Correlation between regional perfusable tissue index (PTI) and maximum circumferential shortening (Ecc) (r = -0.21, p=0.009). In patients with idiopathic DCM, the extent of myocardial fibrosis (PTI) was significantly correlated with impaired contractile function (Ecc) (r = -0.21, P = .009), but not with myocardial perfusion.