How to fight against medical desertification? How to bring more care offers to patients? According to the management of the Grand Paris Nord-Est regional hospital group (GHT), which brings together the hospitals of Aulnay-sous-Bois, Montfermeil and Montreuil, in Seine-Saint-Denis, the shared medical imaging platform (Pimm) is a powerful tool. For its detractors, it constitutes a stranglehold of the private sector on the public hospital.