President Donald Trump defended his energy and health in an interview with The Wall Street Journal and disclosed that he had a CT scan, not an MRI scan, during an October examination about which he and the White House delayed offering details.

Trump, in the interview published Thursday, said he regretted undergoing the advanced imaging on his heart and abdomen during an October visit to Walter Reed National Military Medical Center because it raised public questions about his health. His physician said in a memo the White House released in December that he had “advanced imaging” as a preventative screening for a man his age.

Trump had initially described it as an MRI but said he didn’t know what part of his body he had scanned. A CT scan is a quicker form of diagnostic imaging than an MRI but offers less detail about differences in tissue.

The president’s doctor, Navy Capt. Sean Barbabella, said in a statement released Thursday by the White House that Trump underwent the exam in October because he planned to be at Walter Reed to meet people working there. Trump had already undergone an annual physical in April.

“President Trump agreed to meet with the staff and soldiers at Walter Reed Medical Hospital in October. In order to make the most of the President’s time at the hospital, we recommended he undergo another routine physical evaluation to ensure continued optimal health,” Barbabella said.

Barbabella said he asked the president to undergo either a CT scan or MRI “to definitively rule out any cardiovascular issues” and the results were “perfectly normal and revealed absolutely no abnormalities.”

White House press secretary Karoline Leavitt said in a statement Thursday that the president’s doctors and the White House have “always maintained the President received advanced imaging” but said that “additional details on the imaging have been disclosed by the President himself” because he “has nothing to hide.”

“In retrospect, it’s too bad I took it because it gave them a little ammunition,” Trump said in the interview with The Wall Street Journal. “I would have been a lot better off if they didn’t, because the fact that I took it said, ‘Oh gee, is something wrong?’ Well, nothing’s wrong.”

The 79-year-old became the oldest person to take the oath of office when he was sworn in as president last year and has been sensitive to questions about his health, particularly as he has repeatedly questioned his predecessor Joe Biden’s fitness for office.

Biden, who turned 82 in the last year of his presidency, was dogged by scrutiny of his age and mental acuity at the end of his tenure and during his abandoned attempt to seek reelection.