Functional dyspepsia assessment - current diagnostic methods and new promising techniques

Functional Dyspepsia (FD) is a disorder of gut-brain interaction (DGBI) characterized by chronic symptoms without an organic cause. Diagnosis follows the Rome IV criteria, requiring symptoms for at least six months. FD affects up to 20% of the population, significantly impacting the quality of life and healthcare systems. Upper gastrointestinal endoscopy is often performed to rule out organic disorders but has limited utility in typical FD cases. FD's etiology involves gastric motility alterations, dysbiosis, and immune and central nervous system dysfunction. This review summarizes FD diagnostic methods. A PubMed search was conducted using keywords: Functional Dyspepsia, Gastric Motility Assessment, ROME IV, and Gastric Emptying (GE). Relevant studies were manually reviewed, excluding those unrelated to FD or gastric motility assessment. Despite extensive research on organic gastrointestinal diseases, FD's pathophysiology remains unclear, necessitating further studies. Diagnostic methods include the rapid water and nutrient drink tests for assessing impaired gastric accommodation, hypersensitivity, and delayed gastric emptying. Drinking-ultrasonography and three-dimensional ultrasound evaluate gastric motor and sensory functions. MRI-based assessments provide detailed stomach volume and geometry insights. Gastric emptying scintigraphy and the 13C-gastric emptying breath test measure gastric emptying rates. High-resolution electrogastrography (HR-EGG) assesses gastric myoelectrical activity, while EndoFLIP measures sphincter function. Functional MRI and PET scans analyze brain activity related to FD symptoms.  These methodologies enhance the understanding and management of FD by providing objective measures of gastric motility, accommodation, and sensory function. The integration of these advanced techniques into clinical practice holds the potential to move beyond symptom-based diagnosis, allowing for a more precise, individualized approach to treatment. Standardizing these diagnostic modalities will be crucial in optimizing patient care and alleviating the burden of FD on healthcare systems.