The S&P/ASX 200 Index (ASX: XJO) has returned a respectable 24.1% over the past three years, but this ASX 200 stock has left those gains in the dust.

The rocketing stock in question is health imaging company Pro Medicus Ltd (ASX: PME).

So, just how much has this company returned to longer-term shareholders?

Let's dig in.

ASX 200 stock shooting out the lights

On 10 June 2022, three years (and two days) ago, you could have picked up Pro Medicus shares for $41.38 each.

In afternoon trade today, shares in the ASX 200 stock are up 1.2%, changing hands for $282.50 apiece.

That sees the Pro Medicus share price up an eye-watering 582.9% since June 2022.

Meaning a $5,000 investment in the health imaging company three years ago is now worth (a rounded) $34,145.

But wait.

There's more!

Pro Medicus also pays two modest, fully franked dividends a year.

If you'd bought the ASX 200 stock three years ago, you would have received the past six dividend payouts. All told, those work out to $1.07 a share.

So, let's add that back into today's share price of $282.50. This brings the present accumulated value of Pro Medicus shares bought three years ago to $283.57 each.

And that, in turn, means the ASX healthcare stock has gained an eye-popping 585.3%.

Or enough to turn a $5,000 investment made on 10 June 2022 into $34,264 today.

Boom!

What's been going right for Pro Medicus shares?

Investors have been piling into Pro Medicus shares amid a series of major contract wins for its Visage Imaging Platform.

Most recently, on 8 May, the ASX 200 stock announced a new $20 million, five-year contract with the University of Iowa Health Care.

"They join a long list of Visage 7 clients to opt for a fully cloud-based solution, which, as a result of our CloudPACS strategy, is becoming the standard in the North American healthcare IT market," Pro Medicus CEO Sam Hupert said on the day.

Looking ahead, Hupert added:

Our pipeline remains strong and spans all market segments. As has been the case with many of our recent contracts, this deal is for our 'full stack' comprising all three core Visage products, namely viewer, workflow and archive, a trend we see continuing.

And the ASX 200 stock has been posting impressive growth, as witnessed by its record half-year results, released on 13 February.

Highlights for the six months to 31 December included record half-year revenue of $100.8 million, up 32.2% year over year.

And on the bottom line, the company's net profit was up 42.7% to a record of $51.7 million.