1352174 - In-vivo mapping of myocardial creatine in subjects with obesity before and after bariatric surgery using chemical exchange saturation transfer magnetic resonance imaging

Creatine chemical exchange saturation transfer (CrCEST) is a quantitative metabolic magnetic resonance imaging (CMR) technique for creatine mapping. We used CrCEST CMR to evaluate myocardial creatine changes in patients with obesity before and after bariatric surgery.



Methods: Saline phantom doped with variable concentrations of creatine were first built and scanned to investigate the relationship between creatine signal intensity and concentration. Patients with obesity (body mass index, BMI > 30 kg/m²) who underwent bariatric surgery were enrolled. CMR on a 3T MRI Skyra clinical scanner (Siemens Medical, Germany) was performed before and after the surgery. The imaging protocol included Cine for global function assessment and CrCEST CMR for myocardial creatine mapping. CrCEST CMR scans were performed using FLASH readout. Electrocardiogram triggering and navigator gating were used to reduce the effects of cardiac and respiratory motion. An additional image was acquired without CEST saturation for normalization reference. The segmentation of Cine images was performed on Segment software (Medviso, Sweden). Post-processing CrCEST images was performed with custom-written programs in Matlab (The Mathworks, MA, USA).


Results:

Phantom studies demonstrated creatine signal intensity increases linearly with concentration. Among 13 subjects who underwent CMR before the surgery, only six subjects had completed the follow-up CMR with the median follow-up time of 10 months. Bariatric surgery was effective in lowering the BMI. Myocardial CrCEST signal (CEST_asym) was significantly lower at baseline and significantly higher after bariatric surgery, suggesting an improvement in myocardial creatine content. This was accompanied by improved left ventricular ejection fraction (all p < 0.05).



Conclusion:

In this study, we show the feasibility to utilize CrCEST CMR to detect in vivo myocardial metabolic derangement in obese cohorts before and after bariatric surgery non-invasively. Future studies should validate the technique and findings in more large-scale multicenter research with larger sample sizes.