STANFORD, Calif. — When it comes to math, MRIs may be better than IQs — and even past math scores — at showing whether a tutor can help a child master everything from trapezoids to trigonometry.

A new study from the Stanford University School of Medicine says that the size and circuitry of certain parts of children’s brains are excellent predictors of how well they’ll respond to intensive math tutoring.

The researchers’ most surprising finding was that children’s IQ and math scores had no effect on tutoring outcomes, yet brain scan images “predicted how much a child would learn,” said Vinod Menon, a Stanford professor of psychiatry and behavioral sciences who was the study’s senior author.

The researchers found that the kids who responded the best to tutoring tended to have a larger and more active hippocampus. Named after the Greek word for “seahorse,” the spirally hippocampus is known to play an important role in learning and memory. But its role in mastering specific skills — like math — hadn’t been explored until now.