MRI Parameters as Biomarkers in Cystic Fibrosis (FEMPTO)

Cystic fibrosis (CF) is an inherited condition that affects several organs, including the gut. People with CF often experience uncomfortable digestive symptoms such as bloating, gas, abdominal pain, and constipation. The root cause is that the gut produces thicker-than-normal mucus, which slows things down and makes it harder for the bowel to work properly. Current treatments such as laxatives, enemas, or surgery can be inconvenient and don't always work well. There is a real need for better options, and for a clearer understanding of how the CF gut behaves and responds to treatment. This study will use MRI, a non-invasive imaging technique, to look at how fluid moves through the gut in adults with CF and the impact of linaclotide. Linaclotide is a licensed medication used to treat chronic constipation and irritable bowel syndrome. It works by encouraging the gut to release more fluid, helping things move more easily. It acts locally in the gut and is not absorbed into the bloodstream. Early research suggests it may help in CF in a way that does not rely on correcting the underlying genetic fault, making it a promising avenue to explore. Participants will include people with different bowel habits, including those who tend towards constipation and those who tend towards diarrhoea. The scans will help researchers check whether certain MRI measurements can reliably detect changes in gut fluid and movement. This is a feasibility study; its main objective is to test whether these MRI measurements are useful and practical, and support a sample size calculation, in future CF studies investigating linaclotide effects.