The exhibition, entitled Gritty Brits: New London Architecture, will show the work of David Adjaye, Caruso St John, FAT, muf, Niall McLaughlin and Sergison Bates, as part of an ongoing installation that will look at new architecture from cities around the world.
'But I wanted to show the great work the younger architects are doing in London, and not just display the big names which any lay-person would know, such as Foster and Rogers.'
The exhibition will display more than 150 objects, including six models specifically designed by each practice for the show.
'Pittsburgh has been experiencing a huge period of change,' said Ryan. 'The steel industry disappeared 30 years ago and the city is in need of real regeneration.
'The projects chosen for this display will show how tough, grainy and gritty typographies can be transformed.
'They will show a London very familiar to Londoners, but they will be a far cry from the tourist board pictures Americans will be used to seeing,' he added.
The exhibition runs from 20 January to 3 June at the Carnegie Museum of Art, Pittsburgh.
For more information visit www.cmoa.org