The driver pronounced dead after a three-vehicle collision in Mill Valley this week was Robert Charles Brasch, 80, of Mill Valley, the Marin County coroner’s office said.

The crash happened Monday afternoon near the intersection of Miller Avenue and Camino Alto. Mill Valley police said Brasch was driving a Honda CR-V that struck two other vehicles and went into a ditch.

First responders found Brasch unconscious and in “cardiac arrest,” and pulled him out of the vehicle in an unsuccessful effort to keep him alive, Chief Deputy Coroner Roger Fielding said.

The preliminary investigation suggests Brasch suffered a medical emergency before the crash, police and the coroner’s office said. A forensic examination was planned for Wednesday, and the results of toxicology tests are pending.

Brasch was a radiologist who started at the University of California-San Francisco in 1976 and retired in 2012, said Dr. Chris Hess, chair of the UCSF radiology department.Hess described Brasch as an internationally respected expert in the field who had a pioneering role in magnetic resonance imaging contrast agents, which affect the quality of diagnostic images.

“Bob had a joy for life,” Hess said. “Just a tremendous ability to look into the future of his mentees. He developed an international group of trainees who worked in his lab over decades, and they went on to start their own programs in clinical radiology around the world.”