Clinical implications of catheter probe-assisted endoluminal ultrasonography

Anatomic-manometric correlation of the upper esophageal sphincter: a concurrent US and manometry study

BACKGROUND

The pharyngoesophageal segment commonly referred to as the upper esophageal sphincter (UES) generates a high-pressure zone (HPZ) between the pharynx and the esophagus. However, the exact anatomical components of the UES-HPZ remain incompletely determined.

OBJECTIVE

To systematically define the US signature of various components of the pharyngoesophageal junction and to determine how these structures contribute to the development of the UES-HPZ.

DESIGN

Prospective, experimental study.

SETTING

Tertiary Academic Medical Center.

PATIENTS

This study involved 18 healthy volunteers.

INTERVENTION

We studied 5 participants by using a high-frequency US miniprobe (US-MP) and concurrent fluoroscopy and another 13 participants by using the US-MP and concurrent manometry.

MAIN OUTCOME MEASUREMENTS

Relative contribution of various muscles in the UES-HPZ.

RESULTS

Manometrically, the UES-HPZ had a median length of 4.0 cm (range 3.0-4.5 cm). A C-shaped muscle, believed to represent the cricopharyngeus muscle, was observed for a median length of 3.5 cm (range 2.0-4.0 cm). The oval configuration representing the esophageal contribution to the UES was seen in 10 of 13 participants (77%) at the distal HPZ (esophagus to UES transition zone). The flat configuration of the inferior constrictor muscle was noted in 7 of 13 participants (54%) at the proximal HPZ (UES to pharynx transition zone). There were 4 to 5 wall layers versus 3 layers in the distal and proximal HPZ, respectively. The mean (+/- SD) muscle thickness was relatively constant along the length of the UES-HPZ.

LIMITATIONS

Air artifacts in the UES-HPZ.

CONCLUSION

The configuration and layers of the UES-HPZ vary along its length. The upper esophagus is a significant contributor to the distal UES-HPZ.

High-frequency US catheter-based staging of early esophageal tumors

BACKGROUND

High-frequency catheter US probes provide greater accuracy compared with dedicated echoendoscopes in the staging of superficial esophageal carcinoma. However, it may be difficult and time consuming to obtain acoustic coupling with these devices. The aim of this study was to test a novel catheter US technique for staging superficial esophageal carcinoma.

METHODS

Twelve patients underwent examination with a 2-channel endoscope. US images were obtained with a catheter US probe (20 MHz) fitted with a balloon sheath.

RESULTS

Adequate endoscopic and catheter US images were obtained in all patients. Depth of tumor invasion as determined with the catheter US probe was confirmed in all 5 patients who underwent surgery. No procedure-related complications occurred.

CONCLUSIONS

US with a catheter US probe and sheath allows complete endoscopic examination and preoperative determination of depth of invasion of superficial esophageal carcinoma in a single endoscopic procedure. Preliminary results suggest this technique is accurate and safe.