Bravo pH Monitor

What is the device in the chest? What are potential complications? • Xray of the Week

Figure 1. What is the device in the chest?

Figure 2. Frontal and lateral chest radiograph demonstrates foreign body consistent with Bravo pH Capsule in the esophagus.

Figure 3. Enlarged and lateral chest radiograph demonstrates foreign body consistent with Bravo pH Capsule in the esophagus.

Bravo pH Monitoring System: Radiologic Considerations and Clinical Implications

The Bravo pH monitoring system is a catheter-free, ambulatory device designed to evaluate esophageal acid exposure over 48–96 hours. It is widely used in the diagnosis of gastroesophageal reflux disease (GERD), particularly in patients with persistent symptoms despite medical therapy or in those being considered for anti-reflux surgery [1]. The system consists of a small pH capsule that is temporarily affixed to the esophageal mucosa via endoscopy and transmits pH data to an external receiver. The capsule eventually detaches and passes though the GI tract into the stool. Unlike traditional catheter-based monitoring, Bravo improves patient tolerance and compliance, leading to more accurate symptom correlation and better diagnostic yield [2].

Complications of Bravo pH Monitoring

Although Bravo pH monitoring is minimally invasive, several potential complications have been reported, including:

• Chest pain and discomfort, occurring in 15–20% of patients, occasionally severe enough to require early capsule removal [2].

• Dysphagia or globus sensation, particularly if the capsule is placed too proximally [3].

• Mucosal ulceration and bleeding, especially in patients with pre-existing esophagitis or delayed esophageal clearance [4].

• Capsule misplacement or detachment failure, leading to inaccurate pH readings and potential patient discomfort [5].

• Aspiration or prolonged capsule retention, although rare, requiring endoscopic retrieval if retained beyond 30 days [6].

Radiologic Considerations: Bravo pH Capsule on Imaging

Although not an imaging-based diagnostic tool, radiology plays a key role in evaluating capsule placement and identifying complications.

1. Confirming Capsule Placement

   • The Bravo capsule appears as a small, radiopaque metallic-density structure in the distal esophagus, typically 5–6 cm above the gastroesophageal junction, on fluoroscopy, chest X-ray, or CT [7] (Figs 1-3).

   • Fluoroscopy can confirm proper adherence in cases of chest discomfort or suspected misplacement [8].

2. Assessing for Complications

   • CT imaging may reveal adjacent mucosal thickening, edema, or ulceration in patients with persistent symptoms [9].

   • In suspected prolonged retention, an abdominal X-ray can confirm whether the capsule has passed through the GI tract or remains in place beyond the expected detachment period [10].

   • In rare cases of suspected esophageal perforation, contrast esophagography may demonstrate extraluminal leakage [11].

3. Avoiding Misinterpretation

   • The Bravo capsule can be misinterpreted as a foreign body or endoscopic clip, particularly in oncologic imaging [12].

   • Awareness of its expected location and morphology prevents unnecessary biopsy or surgical consultation [13].

Clinical Utility for Referring Physicians

Radiologists play a crucial role in identifying Bravo-related complications and distinguishing the capsule from pathologic findings. Key contributions include:

• Confirming correct capsule positioning, ensuring the test provides accurate pH data [14].

• Identifying capsule retention, ulceration, or misplacement, which may require repeat endoscopy [15].

• Avoiding misdiagnosis of a retained Bravo capsule as a tumor, lymph node, or foreign body, preventing unnecessary interventions [16].

Conclusion

The Bravo pH monitoring system remains integral to GERD diagnosis, offering prolonged, catheter-free acid monitoring. However, it presents unique radiologic challenges, as it can be mistaken for a foreign body, endoscopic clip, or pathologic mass. Understanding the expected imaging characteristics, potential complications, and appropriate differential considerations allows radiologists to optimize patient management and avoid unnecessary procedures [17].

References

1. Gyawali CP, Kahrilas PJ, Savarino E, et al. Modern diagnosis of GERD: the Lyon Consensus. Gut. 2018;67(7):1351-1362. DOI: 10.1136/gutjnl-2017-314722

2. Savarino E, Bredenoord AJ, Fox M, et al. Expert consensus document: Advances in the physiological assessment and diagnosis of GERD [published correction appears in Nat Rev Gastroenterol Hepatol. 2018 May;15(5):323. doi: 10.1038/nrgastro.2018.32.]. Nat Rev Gastroenterol Hepatol. 2017;14(11):665-676. DOI: 10.1038/nrgastro.2017.130

3. Gawron AJ, Pandolfino JE. Ambulatory reflux monitoring in GERD--which test should be performed and should therapy be stopped?. Curr Gastroenterol Rep. 2013;15(4):316. doi: 10.1007/s11894-013-0316-6

4. Sigakis CJG, Mathai SK, Suby-Long TD, et al. Radiographic Review of Current Therapeutic and Monitoring Devices in the Chest. Radiographics. 2018;38(4):1027-1045. DOI: 10.1148/rg.2018170096

5. Bredenoord AJ, Pandolfino JE, Smout AJ. Gastro-oesophageal reflux disease. Lancet. 2013;381(9881):1933-1942. DOI: 10.1016/S0140-6736(12)62171-0

6. Weusten BL, Roelofs JM, Akkermans LM, Van Berge-Henegouwen GP, Smout AJ. The symptom-association probability: an improved method for symptom analysis of 24-hour esophageal pH data. Gastroenterology. 1994;107(6):1741-1745. DOI: 10.1016/0016-5085(94)90815-x

7. Spechler SJ. Epidemiology and natural history of gastro-oesophageal reflux disease. Digestion. 1992;51 Suppl 1:24-29. DOI: 10.1159/000200911

8. Naik RD, Meyers MH, Vaezi MF. Treatment of Refractory Gastroesophageal Reflux Disease. Gastroenterol Hepatol (N Y). 2020;16(4):196-205. PMCID: PMC8132683

9. Yadlapati R, Pandolfino JE. Personalized Approach in the Work-up and Management of Gastroesophageal Reflux Disease. Gastrointest Endosc Clin N Am. 2020;30(2):227-238. DOI: 10.1016/j.giec.2019.12.002

10. Vakil N, van Zanten SV, Kahrilas P, Dent J, Jones R; Global Consensus Group. The Montreal definition and classification of gastroesophageal reflux disease: a global evidence-based consensus. Am J Gastroenterol. 2006;101(8):1900-1943. DOI: 10.1111/j.1572-0241.2006.00630.x

11. Richter JE, Pandolfino JE, Vela MF, et al. Utilization of wireless pH monitoring technologies: a summary of the proceedings from the esophageal diagnostic working group. Dis Esophagus. 2013;26(8):755-765. DOI: 10.1111/j.1442-2050.2012.01384.x

12. Zerbib F, Roman S, Bruley Des Varannes S, et al. Normal values of pharyngeal and esophageal 24-hour pH impedance in individuals on and off therapy and interobserver reproducibility. Clin Gastroenterol Hepatol. 2013;11(4):366-372. DOI: 10.1016/j.cgh.2012.10.041

13. Katz PO, Dunbar KB, Schnoll-Sussman FH, Greer KB, Yadlapati R, Spechler SJ. ACG Clinical Guideline for the Diagnosis and Management of Gastroesophageal Reflux Disease. Am J Gastroenterol. 2022;117(1):27-56. DOI: 10.14309/ajg.0000000000001538

14. Boeckxstaens GE, Rohof WO. Pathophysiology of gastroesophageal reflux disease. Gastroenterol Clin North Am. 2014;43(1):15-25. DOI: 10.1016/j.gtc.2013.11.001

15. Tutuian R, Castell DO. Reflux monitoring: role of combined multichannel intraluminal impedance and pH. Gastrointest Endosc Clin N Am. 2005;15(2):361-371. DOI: 10.1016/j.giec.2004.10.002

16. Spechler SJ. Comparison of medical and surgical therapy for complicated gastroesophageal reflux disease in veterans. The Department of Veterans Affairs Gastroesophageal Reflux Disease Study Group. N Engl J Med. 1992;326(12):786-792. DOI: 10.1056/NEJM199203193261202

17. Carlson DA, Kathpalia P, Craft J, et al. The relationship between esophageal acid exposure and the esophageal response to volumetric distention. Neurogastroenterol Motil. 2018;30(3):10.1111/nmo.13240. doi: 10.1111/nmo.13240

Kevin M. Rice, MD is the president of Global Radiology CME and is a radiologist with Cape Radiology Group. He has held several leadership positions including Board Member and Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015, Dr. Rice and Natalie Rice founded Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. In 2016, Dr. Rice was nominated and became a semifinalist for a "Minnie" Award for the Most Effective Radiology Educator. He was once again a semifinalist for a "Minnie" for 2021's Most Effective Radiology Educator by AuntMinnie.com. He has continued to teach by mentoring medical students interested in radiology. Everyone who he has mentored has been accepted into top programs across the country including Harvard, UC San Diego, Northwestern, Vanderbilt, and Thomas Jefferson.

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