U.S. diagnostic imaging operator Akumin Inc. has filed for Chapter 11 bankruptcy protection. We lowered our issuer credit rating on the company to 'D' from 'CCC'. At the same time, we lowered our issue-level ratings on the company's revolving credit facility, senior notes due in 2025, and senior notes due in 2028 to 'D' from 'CCC'. We downgraded Akumin after it filed for bankruptcy under Chapter 11 of the U.S. Bankruptcy Code. This follows a lengthy period of operating challenges including stagnant revenue for several years, coupled with a very high interest burden (especially following the end of the payment-in-kind period for the unrated subordinated debt). We expect to reassess our ratings on the company and its new capital structure