Nuclear medicine imaging in the evaluation of functional gastrointestinal disorders

The functional gastrointestinal disorders (FGIDs) are an enigmatic group of maladies of the GI system which, until recently, were poorly understood and often neglected by clinicians. These disorders present with a constellation of GI tract systems, such as nausea, vomiting, abdominal bloating and diarrhoea. Following detailed clinical and imaging evaluation in the search for organic disease, if no such cause is found, the diagnostic and therapeutic process in these patients can often diminish in clinical priority and importance. Over the last three decades, however, the Rome Foundation has focused academic and clinical attention on the FGIDs by bringing together expert opinion and evidence in a consensus process that has been instrumental in improving the understanding of the complex, multifactorial pathogenesis of the FGIDs as important causes of GI morbidity. Established functional nuclear medicine (NM) techniques have an important role in the evaluation of some of these disorders, notably in functional gastroduodenal disorders (Tc-labelled gastric emptying scintigraphy – GES), functional bowel disorders (23-[Se]-25-tauroselcholic acid – SeHCAT) and functional gallbladder disorders (Tc-hepatobiliary iminodiacetic acid – HIDA scintigraphy). These three NM techniques, and their clinical relevance to the FGIDs, will be discussed in more detail in this article, with particular emphasis on the importance of standardisation of the technique and evaluation of clinical outcomes based on the results of these tests.