The 23-year-old left-handed opener had to retire hurt after he was struck a painful blow on the elbow by England fast bowler Mark Wood.
The incident took place in the fourth over of the penultimate match of the five-game one-day international series at Trent Bridge, when Imam missed an intended pull off an 89 mile-per-hour (143 kilometres-per-hour) delivery from the Durham paceman.
Imam, fresh from his career-best 151 in the third ODI at Bristol on Tuesday, fell to the ground and winced on the turf in the agony.
The nephew of Pakistan great and selection chief, Inzamam-ul-Haq received several minutes' treatment before retiring hurt on three not out, with the tourists then nine without loss.
A statement issued by Pakistan management said Imam had been taken to hospital for a precautionary X-ray, with a further update on his condition expected later Friday.
World Cup hosts and tournament favourites England lead the five-match series 2-0.