1. Esophageal function testing with combined multichannel intraluminal impedance and manometry: Multicenter study in healthy volunteers 
Radu Tutuian, Marcelo F. Vela, Nagammapudur S. Balaji, James L. Wise, Joseph A. Murray, Jeffrey H. Peters, Steven S. Shay, Donald O. Castell 
Clinical Gastroenterology and Hepatology 
Volume 1, Issue 3, Pages (May 2003)
DOI: /S (03)
Copyright © 2003 American Gastroenterological Association Terms and Conditions

2. Fig. 1
8-channel combined MII/EM catheter. Circumferential solid-state pressure sensors located in LES high-pressure zone (P-4) and 5 cm above it (P-3), unidirectional solid-state pressure sensors located 10 cm (P-2) and 15 cm (P-1) above LES. Impedance-measuring segments centered at 5 cm (Z-4), 10 cm (Z-3), 15 cm (Z-2), and 20 cm (Z-1) above LES.
Clinical Gastroenterology and Hepatology 2003 1, DOI: ( /S (03) )
Copyright © 2003 American Gastroenterological Association Terms and Conditions

3. Fig. 2
Impedance changes observed during bolus transit over a single pair of measurement rings separated by 2 cm. A rapid rise in resistance is noted when air traveling in front of the bolus head reaches the impedance-measuring segment followed by a drop in impedance once higher conductive bolus material passes the measuring site. Bolus entry is considered at the 50% drop in impedance from baseline relative to nadir and bolus exit at the 50% recovery point from nadir to baseline. Lumen narrowing produced by the contraction transiently increases the impedance above baseline.
Clinical Gastroenterology and Hepatology 2003 1, DOI: ( /S (03) )
Copyright © 2003 American Gastroenterological Association Terms and Conditions

4. Fig. 3
Definitions of impedance parameters: (A) TBTT as time elapsed between bolus entry at 20 cm above LES and bolus exit at 5 cm above LES, (B) bolus head advance time as time elapsed between bolus entry at 20 cm above LES and bolus entry at 15, 10, and 5 cm above LES, (C) bolus presence time (BPT) as time elapsed between bolus entry and bolus exit at each impedance measuring site (5, 10, 15, and 20 cm above LES), and (D) segmental transit times (STT) as time elapsed between bolus entry at a given level above LES and bolus exit at the nearby lower level.
Clinical Gastroenterology and Hepatology 2003 1, DOI: ( /S (03) )
Copyright © 2003 American Gastroenterological Association Terms and Conditions

5. Fig. 4
Bolus head advance times (thin arrows) relative to bolus entry at 20 cm above LES and bolus presence times (thick arrows) of liquid and viscous boluses at 20, 15, 10, and 5 cm above LES. Segments represent bolus presence time at 20, 15, 10, and 5 cm above LES. Liquid boluses have shorter head advance times and longer bolus presence times compared to viscous boluses at any given level.
Clinical Gastroenterology and Hepatology 2003 1, DOI: ( /S (03) )
Copyright © 2003 American Gastroenterological Association Terms and Conditions

6. Fig. 5
Example of manometrically ineffective contractions with (A) complete and (B) incomplete bolus transit. MII and EM channels indicate the level above the LES.
Clinical Gastroenterology and Hepatology 2003 1, DOI: ( /S (03) )
Copyright © 2003 American Gastroenterological Association Terms and Conditions

7. Fig. 6
Total bolus transit time of manometrically normal, ineffective, and simultaneous swallows with complete bolus transit for liquid and viscous materials. Kruskal-Wallis H test indicates statistically significant difference (P < 0.001) between different manometric categories for viscous swallows. Kruskal-Wallis test indicates bolus transit of ineffective viscous swallows with complete transit is significantly longer (P < 0.05) compared with total bolus transit of normal viscous swallows.
Clinical Gastroenterology and Hepatology 2003 1, DOI: ( /S (03) )
Copyright © 2003 American Gastroenterological Association Terms and Conditions