Magnetic Resonance Imaging for the diagnosis and management of acute colonic diverticulitis: a review of current and future use

Emergency medicine updates: Acute diverticulitis

INTRODUCTION

Acute diverticulitis is a condition commonly seen in the emergency department (ED). Therefore, it is important for emergency medicine clinicians to be aware of the current evidence regarding the diagnosis and management of this disease.

OBJECTIVE

This paper evaluates key evidence-based updates concerning acute diverticulitis for the emergency clinician.

DISCUSSION

Diverticulitis is a complication of diverticulosis and most commonly affects the sigmoid and descending colon in Western countries. History and examination can suggest the diagnosis, with abdominal pain and tenderness in the left lower quadrant being the most common symptom and sign, respectively. Change in bowel habits and fever may also occur. Laboratory testing may demonstrate leukocytosis or an elevated C-reactive protein. Imaging options can include computed tomography (CT) of the abdomen and pelvis with intravenous contrast, magnetic resonance imaging (MRI), or ultrasound (US), though most classification systems for diverticulitis incorporate CT findings. While the majority of diverticulitis cases are uncomplicated, complications may affect up to 25% of patients. Treatment of complicated diverticulitis requires antibiotics and surgical consultation. Antibiotics are not required in select patients with uncomplicated diverticulitis. Appropriate patients for supportive care without antibiotics should be well-appearing, have pain adequately controlled, be able to tolerate oral intake, be able to follow up, have no complications, and have no immunocompromise or severe comorbidities.

CONCLUSIONS

An understanding of literature updates can improve the ED care of patients with acute diverticulitis.

ACR Appropriateness Criteria® Left Lower Quadrant Pain: 2023 Update

The differential diagnosis for left lower quadrant pain is wide and conditions range from the benign and self-limited to life-threatening surgical emergencies. Along with patient history, physical examination, and laboratory tests, imaging is often critical to limit the differential diagnosis and identify life-threatening abnormalities. This document will discuss the guidelines for the appropriate use of imaging in the initial workup for patients who present with left lower quadrant pain, patients with suspected diverticulitis, and patients with suspected complications from diverticulitis. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Magnetic Resonance Imaging of the Gastrointestinal Tract: Current Role, Recent Advancements and Future Prospectives

This review focuses on the role of magnetic resonance imaging (MRI) in the evaluation of the gastrointestinal tract (GI MRI), analyzing the major technical advances achieved in this field, such as diffusion-weighted imaging, molecular imaging, motility studies, and artificial intelligence. Today, MRI performed with the more advanced imaging techniques allows accurate assessment of many bowel diseases, particularly inflammatory bowel disease and rectal cancer; in most of these diseases, MRI is invaluable for diagnosis, staging, and disease monitoring under treatment. Several MRI parameters are currently considered activity biomarkers for inflammation and neoplastic disease. Furthermore, in younger patients with acute or chronic GI disease, MRI can be safely used for short-term follow-up studies in many critical clinical situations because it is radiation-free. MRI assessment of functional gastro-esophageal and small bowel disorders is still in its infancy but very promising, while it is well established and widely used for dynamic assessment of anorectal and pelvic floor dysfunction; MRI motility biomarkers have also been described. There are still some limitations to GI MRI related to high cost and limited accessibility. However, technical advances are expected, such as faster sequences, more specific intestinal contrast agents, AI analysis of MRI data, and possibly increased accessibility to GI MRI studies. Clinical interest in the evaluation of bowel disease using MRI is already very high, but is expected to increase significantly in the coming years.

Infection or Inflammation: Are Uncomplicated Acute Appendicitis, Acute Cholecystitis, and Acute Diverticulitis Infectious Diseases?

Background: It is recognized increasingly that common surgical infections of the peritoneal cavity may be treated with antibiotic agents alone, or source control surgery with short-course antimicrobial therapy. By extension, testable hypotheses have emerged that such infections may not actually be infectious diseases, but rather represent inflammation that can be treated successfully with neither surgery nor antibiotic agents. The aim of this review is to examine extant data to determine which of uncomplicated acute appendicitis (uAA), uncomplicated acute calculous cholecystitis (uACC), or uncomplicated mild acute diverticulitis (umAD) might be amenable to management using supportive therapy alone, consistent with the principles of antimicrobial stewardship. Methods: Review of pertinent English-language literature and expert opinion. Results: Only two small trials have examined whether uAA can be managed with observation and supportive therapy alone, one of which is underpowered and was stopped prematurely because of challenging patient recruitment. Data are insufficient to determine the safety and efficacy of non-antibiotic therapy of uAA. Uncomplicated acute calculous cholecystitis is not primarily an infectious disease; infection is a secondary phenomenon. Even when bactibilia is present, there is no high-quality evidence to suggest that mild disease should be treated with antibiotic agents. There is evidence to indicate that antibiotic prophylaxis is indicated for urgent/emergency cholecystectomy for uACC, but not in the post-operative period. Uncomplicated mild acute diverticulitis, generally Hinchey 1a or 1b in current nomenclature, does not benefit from antimicrobial agents based on multiple clinical studies. The implication is that umAD is inflammatory and not an infectious disease. Non-antimicrobial management is reasonable. Conclusions: Among the considered disease entities, the evidence is strongest that umAD is not an infectious disease and can be treated without antibiotic agents, intermediate regarding uACC, and lacking for uAA. A plausible hypothesis is that these inflammatory conditions are related to disruption of the normal microbiome, resulting in dysbiosis, which is defined as an imbalance of the natural microflora, especially of the gut, that is believed to contribute to a range of conditions of ill health. As for restorative pre- or probiotic therapy to reconstitute the microbiome, no recommendation can be made in terms of treatment, but it is not recommended for prevention of primary or recurrent disease.

Diagnosis and Management of Acute Left-Sided Colonic Diverticulitis: A Clinical Guideline From the American College of Physicians

DESCRIPTION

The American College of Physicians (ACP) developed this guideline to provide clinical recommendations on the diagnosis and management of acute left-sided colonic diverticulitis in adults. This guideline is based on current best available evidence about benefits and harms, taken in the context of costs and patient values and preferences.

METHODS

The ACP Clinical Guidelines Committee (CGC) developed this guideline based on a systematic review on the use of computed tomography (CT) for the diagnosis of acute left-sided colonic diverticulitis and on management via hospitalization, antibiotic use, and interventional percutaneous abscess drainage. The systematic review evaluated outcomes that the CGC rated as critical or important. This guideline was developed using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology.

TARGET AUDIENCE AND PATIENT POPULATION

The target audience is all clinicians, and the target patient population is adults with suspected or known acute left-sided colonic diverticulitis.

RECOMMENDATION 1

ACP suggests that clinicians use abdominal CT imaging when there is diagnostic uncertainty in a patient with suspected acute left-sided colonic diverticulitis (conditional recommendation; low-certainty evidence).

RECOMMENDATION 2

ACP suggests that clinicians manage most patients with acute uncomplicated left-sided colonic diverticulitis in an outpatient setting (conditional recommendation; low-certainty evidence).

RECOMMENDATION 3

ACP suggests that clinicians initially manage select patients with acute uncomplicated left-sided colonic diverticulitis without antibiotics (conditional recommendation; low-certainty evidence).

Value of high-field magnetic resonance imaging for diagnosis and classification of acute colonic diverticulitis

OBJECTIVES

Due to limited and outdated literature, the role of magnetic resonance imaging (MRI) in the diagnostic work-up of acute colonic diverticulitis (ACD) is still under debate. The purpose of this study was to compare the performance of modern high-field MRI and multidetector computed tomography (MDCT) in the diagnosis and classification of ACD.

METHODS

In our prospective study 24 emergency patients with the clinical diagnosis of ACD received MDCT and high-field MRI. Imaging features of ACD were assessed and categorized according to the classification of diverticular disease (CDD) by three independent readers. Results were matched with the final clinical report.

RESULTS

MRI with a specialized examination protocol clearly depicted all relevant findings of ACD. Statistical analysis resulted in an almost perfect strength of agreement between CT and MRI across all readers for the final CDD category (κ = 0.94) and the stage-related image features (κ = 0.98). Moderate agreement was seen for the detection of micro-abscesses (κ = 0.78), with a slight advantage for MRI.

CONCLUSION

Modern high-field MRI is fully comparable to MDCT in the assessment of ACD and has the potential to serve as a first-line imaging tool.