Vital signs investigation in subjects undergoing MR imaging at 8T.

PURPOSE This study investigates physiologic vital signs in subjects, with and without cerebral pathologies, undergoing ultra-high-field (UHF) 8T MR imaging. METHODS AND SUBJECTS Eighteen normal subjects and 74 subjects with cerebral pathology consented for 8T UHF MR imaging. T2*-weighted gradient-echo and T2-weighted rapid acquisition relaxation excitement sequences were used. Physiologic vital signs measured included systolic blood pressure, diastolic blood pressure, mean arterial pressure, electrocardiogram, heart rate (HR), respiratory rate (RR), and pulse oxygen saturation rate. They were collected before, during, and after imaging. Mean vital sign values at different stages were calculated and compared. Subjects were interviewed after imaging. RESULTS No adverse vital sign change was detected. Statistically significant changes after imaging included a HR decrease from 65.2 beats per minute (bpm) to 60.3 bpm (P = .001, paired Student t test) in the normal group and a RR increase from 14.5 respirations per minute (rpm) to 15.1 rpm (P = .001, paired Student t test) in the patient group. Transient vertigo sensation was reported by 27% of normal subjects and 11% of subjects with cerebral pathologies. One normal subject and one subject with cerebral pathology reported an episode of nausea and vomiting. CONCLUSION The current neurologic human MR imaging procedure at 8T UHF has no serious adverse effects on major physiologic vital signs in either normal subjects or patients. Transient vertigo, nausea, and vomiting were identified as potential risks.