Assessment of sensations experienced by subjects during MR imaging examination at 7T

We investigated sensations experienced by a large number of subjects during magnetic resonance (MR) imaging examinations using a 7-tesla scanner and slow table-feed speed.

After examinations at 7T, 504 of 508 consecutive subjects completed questionnaires using an 11-point scale to rate 14 potential sensations and symptoms during table movement and stationary positioning of the table. We compared scores among the sensations and between table conditions and the mean values of the scores with those reported in previous studies and examined correlations between the scores and subject characteristics.

Vertigo and feelings of curving or leaning in the right or left direction during table movement were experienced frequently and markedly compared to other sensations and sensations experienced when the table was stationary (P < 0.01) and were correlated with subject age and examination time (P < 0.05). However, moderate to severe (scores of 5 to 10) vertigo and a curving/leaning feeling during table movement were noted in only 10.5% (vertigo) and 10.9% (curving/leaning) of subjects, and the mean vertigo score, 1.26, appeared to be substantially lower than that reported in a previous study. Reports of a metallic taste, nausea, and light flashes were significantly rarer and weaker than other sensations (P < 0.05).

Vertigo and feelings of curving during table movement were the most frequent sensations reported during MR imaging examination at 7T. However, the occurrence and severity were low and mild, presumably because of the slow table-feed speed, which suggests that most patients and volunteers found discomfort at 7T acceptable.