Synopsis Contrast-enhanced CT examination can influence H-MRI measurements performed within 24h after the CT scan, due to a reduction in water T and T caused by the iodinated contrast agents used in CT. We have investigated whether contrast from a previous CT examination would also influence metabolic measurements made using P-MRS, by measuring the T of H and P signals in human blood. We find that iodinated CT contrast agent has no effect on phosphorus T s. Therefore, P-MRS examinations will not be influenced by prior CT (unlike H-MRI scans).