Quantification of Intramyocardial Lipid by Proton Magnetic Resonance Spectroscopy

Not Applicable

Completed

Conditions: Heart Transplantation

Interventions: Procedure: Ex vivo heart biopsy
Procedure: Magnetic Resonance Spectroscopy

Registration Number: NCT00469911

Lead Sponsor: Washington University School of Medicine

Brief Summary: Accumulation of triglycerides in heart tissue has been associated with changes in left ventricular function which can lead to heart failure. Proton magnetic resonance spectroscopy is currently the only non-invasive in vivo method to measure myocardial triglycerides content. The primary goal of this study was to determine if Magnetic Resonance Spectroscopy could effectively measure myocardial triglyceride content in myocardial heart tissue. Thus, quantitative and reliable techniques to monitor in vivo triglyceride accumulation in the heart are important for disease diagnosis and management. Currently, no such imaging method exists.

Detailed Description: Because routine biopsy of the myocardium is not feasible, MRS is the most promising technique for the quantification of myocardial triglycerides. MRS is routinely used to precisely characterize metabolite concentrations in muscle and liver. 14-16 Studies such as monitoring the levels of deoxymyoglobin and real-time tracking of the postprandial accumulation of cellular lipids are examples of its diversity and potential.15,17,18 Generally, these studies suggest that the reproducibility of MRS is between 2 and 6%.18,19 In vivo cardiac MRS provides unique challenges because of the requirement to compensate for concurrent heart and lung motion. Using cardiac and respiratory gating to minimize motional artifacts, an initial validation study found a variation of 17% for sequential measurements, attributing the major error to residual motional effects. 20 Moreover, measurements were limited to the inter-ventricular septum. Using navigator and cardiac gating appeared to give a slight, 4%, improvement, but this was a preliminary study and no validation was done.21 For a comprehensive clinical validation, other reproducibility factors must be addressed. Variations due to post-processing, coil placement and calibration, trigger reproducibility, internal versus external standard, shimming, and protocol sequence variables such as pulse quality, gradient strength, voxel size, relaxation time, echo time, and the number of scan repetitions are all known sources of reproducibility. 17,19,22-24 All of these variables must be characterized in order to achieve optimal inter- scanner and subject reproducibility along with accurate treatment tracking capability. Therefore, 10 normal healthy volunteers were imaged to determine the reliability of the MRS protocol with test-re-test measurements. The 8 heart transplant patients were imaged prior to their routine heart biopsies, and then the myocardial biopsy tissue was measure and compared to the pre-biopsy images.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 18

Inclusion Criteria

healthy volunteers
heart transplant patients
undergoing post transplant endomyocardial biopsy
not experiencing significant rejection
heart transplant patients must be 18-30 years old.

Exclusion Criteria

<18 or >45
pregnant
significant systemic illness
actively ill
acute transplant rejection
any condition that would prevent a participant from completing the NMR spectroscopy (i.e pacemakers, claustrophobia)

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Ex vivo heart biopsy	Ex vivo heart biopsy	Patients will have their normal routine clinical heart biopsy of myocardial heart tissue.
Magnetic Resonance Spectroscopy	Magnetic Resonance Spectroscopy	Patients will have Magnetic Resonance Spectroscopy to measure in vivo accumulation of triglycerides in myocardial tissue

Primary Outcome Measures

Name	Time	Method
Correlation Co-efficient Between MRS Spectroscopy and Endomyocardial Biopsy in Heart Transplant Participants	2 to 10 days	Participants first had MRS spectroscopy then the MRS spectroscopy images were compared to endomyocardial biopsy

Secondary Outcome Measures