(85a) Mapping Gastrointestinal Disease

The convergence of engineering and medicine presents a compelling opportunity to apply traditional engineering principles to diagnose and treat challenging diseases.  For example, the disease eosinophilic esophagitis (EoE) causes frequent ER visits when the esophagus narrows or strictures, blocking flow of saliva and swallowed solids as small as a pea.  Patients with EoE may choke without medical help.  Evaluation of esophageal tissues in EoE patients finds patchy invasion of eosinophils, a type of white blood cell normally absent.  Although endoscopy and biopsy collection is currently recommended for diagnosis, this procedure is invasive, and up to 20% of patients may be misdiagnosed due to the patchiness of eosinophil invasion.  Our team is developing a new class of solid ultrasound contrast agents—a slurry of insulin particles—to provide a less invasive way to diagnose EoE and other gastrointestinal (GI) diseases.  Patients simply drink the slurry, the particles bind to eosinophil-enriched tissues, and an external ultrasound probe detects the bound particle distribution as a signal of eosinophil concentrations throughout the esophagus.  However, significant engineering and clinical questions remain.  Can significant surface binding occur even though the bolus transport time is only 6 to 15 s?  What liquid rheology most enhances particle binding?  What insight can be gained from the recent treatment successes of viscous budesonide, a suspension of glucocordicoid (steroid) particles?  How does stricturing affect esophageal fluid mechanics and agent delivery?  Can the adult esophagus be imaged through the rib cage?  Can these contrast agents be shaped and distinguished in the multiphase milieu of the GI tract?  This talk addresses each of these questions essential to the development of this new class of contrast agents to diagnose a broad range of gastrointestinal diseases.