Pictorial review of chronic ketamine abuse on urinary and biliary systems: what a radiologist needs to know.

Ketamine abuse has increased in prevalence in the UK over the last decade, becoming more commonly abused than cocaine in young people. This pictorial review is a primer for radiologists on the pharmacology, pathophysiology, and varying imaging presentations of ketamine abuse across multiple modalities. The review discusses the changing epidemiology of ketamine abuse, the fundamentals of ketamine pharmacology, and pathophysiology of ketamine-related pathologies. We have included three cases of long-term ketamine abuse, including ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine studies which best demonstrate the varying appearances which can be encountered. Chronic ketamine abuse will lead to strictures in both the urinary and biliary tracts. The cases demonstrate examples of uropathy and cholangiopathy identified either together or in isolation. Within the renal tract, this includes the typical ketamine bladder, diffuse urothelial thickening, irregular strictures, and hydronephrosis. In mercaptoacetyltriglycine (MAG3) renogram or renal dimercaptosuccinic acid (DMSA), impaired renal cortical uptake with a slowly rising renogram curve or areas of cortical scarring can be seen. Similarly, in the biliary tree, multiple, irregular strictures, with dilatation of the intrahepatic and extrahepatic ducts can be seen. The mainstay of management in these cases is ketamine cessation, but certain surgical procedures are use in more severe cases, as determined by the urology team. By highlighting the common imaging presentations of ketamine-related pathology, these can be more quickly and easily identified by a radiologist. This can lead to timelier referral to the appropriate services and intervention to benefit these patients.