Use of Endoluminal Ultrasound to Evaluate Gastrointestinal Motility

Abstract

The use of high-frequency ultrasound transducers in the gastrointestinal tract (GI) has already yielded remarkable findings concerning the anatomy, physiology and pathophysiology of the GI tract and of various motility disorders. These transducers have made completely invisible portions of the GI tract (the longitudinal smooth muscle, muscles of the upper esophageal sphincter, components of the gastroesophageal junction high-pressure zone, and the muscle of the anal sphincter complex) accessible to investigation. Use of simultaneous ultrasound and manometry has allowed the exploration of the normal physiology of peristaltic contraction. The components of the high-pressure zone of the distal and proximal esophagus have been isolated and the movement of these components has been studied individually and as a group. Various esophageal motility disorders have been investigated including achalasia, scleroderma, Barrett’s esophagus and diffuse esophageal spasm. The possible etiology of the symptoms of esophageal chest pain and heartburn (sustained esophageal contractions of the longitudinal smooth muscle), have been studied. The possible underlying pathophysiology of GERD (the missing gastric clasp and sling fiber pressure profile) has been explored. Three-dimensional high-frequency ultrasound imaging has allowed the peristaltic contraction sequence to be viewed in a completely new and unique manner. The biomechanics of both esophageal contraction and the gastroesophageal junction high-pressure zone have been investigated and the mechanical advantage of esophageal shorting has been studied. The mechanism of action of standard surgical and newer endoscopic therapies for GERD has been defined. Future applications of this technology are limited only by our imagination.

Study of the Behavior of a Bell-Shaped Colonic Self-Expandable NiTi Stent under Peristaltic Movements

“…Cycling loads would cause stent breaks by cumulative damage and fatigue. However, the frequency of peristaltic movements is less than the corresponding to coronary stents [34]. …”

Defective Mucosal Movement at the Gastroesophageal Junction in Patients with Gastroesophageal Reflux Disease

“…A high-resolution (20MHz) ultrasound transducer (Olympus UM-3R probe on Olympus EU-M30S ultrasound system, Olympus America, Center Valley, PA) was attached to a 3.0-F manometric catheter and placed at the GEJ high-pressure zone as previously described [10]. …”

“…The esophageal MMS can be distinguished from the gastric MMS by the thickness of the second hypo-echoic layer [10,11]. (Figure 1)…”

Endoscopy in the Diagnosis and Management of Motility Disorders

“…The additional novel modality of three-dimensional high-frequency ultrasound supplied new imaging and understanding of the peristaltic contraction sequences of the esophagus and ano-rectum. EUS has an important role in identifying anal sphincter defects that correlate well with manometric abnormalities and allow planning of management strategies [66,67].…”