IDSA Guidelines on the Risk Assessment, Diagnostic Imaging, and Microbiological Evaluation of Complicated Intra-Abdominal Infections

Update History

Overview of Recommendations

Abstract 

Adults with Suspected Acute Diverticulitis

Section last reviewed and updated on 03/01/2023

Last literature search conducted 10/22/2022

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In adults with suspected acute diverticulitis, should CT, US, or MRI be obtained as the initial imaging modality?

Results:

A comprehensive search identified 7 observational studies meeting eligibility on whether to use CT, US, or MRI to diagnose diverticulitis.^2-8 Three studies addressed the diagnostic accuracy of CT or MRI in our exact patient population, i.e., patients with suspected diverticulitis.^2,4,8 We did not find any studies addressing the diagnostic accuracy of US in only patients with suspected diverticulitis; however, we found 4 studies addressing the diagnostic accuracy of US or CT in patients with abdominal pain.^3,5-7 No studies addressing the diagnostic accuracy of MRI were found for this broader patient population.

Summary of evidence for imaging modalities compared to pathology for diagnosing acute diverticulitis:

Rationale for Recommendations:

CT is suggested as the initial imaging modality for patients with suspected diverticulitis due to its high diagnostic accuracy for diverticulitis. Additionally, CT can identify complications associated with diverticulitis and can be used to rule out other causes of abdominal pain.^1,9,10 Compared to MRI, CT is more readily available, often more feasible, less costly, and may cause less distress for patients with a sensitivity to noise or confined spaces. Compared to US, obtaining a CT as the initial imaging test may decrease the need for additional imaging, resulting in saved time and resources. These benefits outweigh the risks attributed to CT of radiation exposure^11,12 and contrast-associated side effects (e.g., contrast-induced nephropathy).

References:

1. Expert Panel on Gastrointestinal Imaging: Weinstein S, Kim DH, Fowler, KJ, et al. ACR Appropriateness Criteria® Left Lower Quadrant Pain. Accessed October 3, 2023. https://acsearch.acr.org/docs/69356/Narrative/
2. Heverhagen JT, Sitter H, Zielke A, Klose KJ. Prospective evaluation of the value of magnetic resonance imaging in suspected acute sigmoid diverticulitis. Dis Colon Rectum 2008; 51(12): 1810-5.
3. Lee IK, Jung SE, Gorden DL, et al. The diagnostic criteria for right colonic diverticulitis: prospective evaluation of 100 patients. Int J Colorectal Dis 2008; 23(12): 1151-7.
4. Meyer S, Schmidbauer M, Wacker FK, Ringe KI. To fill or not to fill? - Value of the administration of positive rectal contrast for CT evaluation of diverticular disease of the colon. Rofo 2021; 193(7): 804-12.
5. Tomizawa M, Shinozaki F, Hasegawa R, et al. Abdominal ultrasonography for patients with abdominal pain as a first-line diagnostic imaging modality. Exp Ther Med 2017; 13(5): 1932-6.
6. Toorenvliet BR, Bakker RF, Breslau PJ, Merkus JW, Hamming JF. Colonic diverticulitis: a prospective analysis of diagnostic accuracy and clinical decision-making. Colorectal Dis 2010; 12(3): 179-86.
7. van Randen A, Laméris W, van Es HW, et al. A comparison of the accuracy of ultrasound and computed tomography in common diagnoses causing acute abdominal pain. Eur Radiol 2011; 21(7): 1535-45.
8. Weinrich JM, Bannas P, Avanesov M, et al. MDCT in the setting of suspected colonic diverticulitis: Prevalence and diagnostic yield for diverticulitis and alternative diagnoses. AJR Am J Roentgenol 2020; 215(1): 39-49.
9. Ferzoco LB, Raptopoulos V, Silen W. Acute diverticulitis. N Engl J Med 1998; 338(21): 1521-6.
10. Wolfe C, Halsey-Nichols M, Ritter K, McCoin N. Abdominal pain in the emergency department: How to select the correct imaging for diagnosis. Open Access Emerg Med 2022; 14: 335-45.
11. Shah KH, Slovis BH, Runde D, Godbout B, Newman DH, Lee J. Radiation exposure among patients with the highest CT scan utilization in the emergency department. Emerg Radiol 2013; 20(6): 485-91.
12. Sodickson A, Baeyens PF, Andriole KP, et al. Recurrent CT, cumulative radiation exposure, and associated radiation-induced cancer risks from CT of adults. Radiology 2009; 251(1): 175-84.

Pregnant Adults with Suspected Acute Diverticulitis

Section last reviewed and updated on 03/01/2023

Last literature search conducted 10/22/2022

[View full manuscript here]

[View full appendix here]

In pregnant adults with suspected acute diverticulitis, should CT, US, or MRI be obtained as the initial imaging modality?

Results:

We did not find any studies addressing diagnostic accuracy of imaging modalities for pregnant patients with suspected diverticulitis. However, we considered evidence from non-pregnant adults along with the balance between benefits and harms (e.g., radiation exposure) of each imaging modality.