Feasibility of rapid-sequence ³¹P magnetic resonance spectroscopy in cardiac patients

Purpose: To determine the clinical feasibility of rapid-sequence phosphorus-31 magnetic resonance spectroscopy (³¹P -MRS) of the heart with cardiac patients using a 1.5T clinical MR system. Material and Methods: Twenty cardiac patients, i.e. dilated cardiomyopathy (DCM) 13 cases, hypertrophic cardiomyopathy (HCM) 3 cases, hypertensive heart diseases (HHD) 3 cases, and aortic regurgitation (AR) 1 case were examined using rapid cardiac ³¹P-MRS. Complete three-dimensional localization was performed using a two-dimensional phosphorus chemical-shift imaging sequence in combination with 30-mm axial sliceselective excitation. The rapid-sequence ³¹P-MRS procedure was phase encoded in arrays of 8 × 8 steps with an average of 4 acquisitions. The total examination time, including proton imaging and shimming, for the rapid cardiac ³¹P-MRS procedure, ranged from 10 to 15 min, depending on the heart rate. Student's t test was used to compare creatine phosphate (PCr)/adenosine triphosphate (ATP) ratios from the cardiac patients with those of the control subjects (n= 13). Results: The myocardial PCr/ATP ratio obtained by rapid ³¹P-MRS was significantly lower (P <0.001) in DCM patients (1.82 ± 0.33, mean ± SD), and in patients with global myocardial dysfunction (combined data for 20 patients: 1.89 ± 0.32) than in normal volunteers (2.96 ± 0.59). These results are similar to previous studies. Conclusion: Rapid-sequence ³¹P-MRS may be a valid diagnostic tool for patients with cardiac disease.