This is the current release of the guideline.

This guideline updates a previous version: Miller FH, Bree RL, Rosen MP, Foley WD, Gay SB, Grant TH, Heiken JP, Huprich JE, Lalani T, Sudakoff GS, Greene FL, Rockey DC, Expert Panel on Gastrointestinal Imaging. ACR Appropriateness Criteria® left lower quadrant pain. [online publication]. Reston (VA): American College of Radiology (ACR); 2008. 5 p.

The appropriateness criteria are reviewed biennially and updated by the panels as needed, depending on introduction of new and highly significant scientific evidence.

Left lower quadrant pain, suspected diverticulitis

To evaluate the appropriateness of initial radiologic examinations for patients with left lower quadrant pain and suspected diverticulitis

Patients with left lower quadrant pain and suspected diverticulitis

Utility of radiologic examinations in differential diagnosis

Literature Search Procedure

The Medline literature search is based on keywords provided by the topic author. The two general classes of keywords are those related to the condition (e.g., ankle pain, fever) and those that describe the diagnostic or therapeutic intervention of interest (e.g., mammography, MRI).

The search terms and parameters are manipulated to produce the most relevant, current evidence to address the American College of Radiology Appropriateness Criteria (ACR AC) topic being reviewed or developed. Combining the clinical conditions and diagnostic modalities or therapeutic procedures narrows the search to be relevant to the topic. Exploding the term "diagnostic imaging" captures relevant results for diagnostic topics.

The following criteria/limits are used in the searches.

1. Articles that have abstracts available and are concerned with humans.
2. Restrict the search to the year prior to the last topic update or in some cases the author of the topic may specify which year range to use in the search. For new topics, the year range is restricted to the last 5 years unless the topic author provides other instructions.
3. May restrict the search to Adults only or Pediatrics only.
4. Articles consisting of only summaries or case reports are often excluded from final results.

The search strategy may be revised to improve the output as needed.

The total number of source documents identified as the result of the literature search is not known.

Strength of Evidence Key

Category 1 - The conclusions of the study are valid and strongly supported by study design, analysis, and results.

Category 2 - The conclusions of the study are likely valid, but study design does not permit certainty.

Category 3 - The conclusions of the study may be valid, but the evidence supporting the conclusions is inconclusive or equivocal.

Category 4 - The conclusions of the study may not be valid because the evidence may not be reliable given the study design or analysis.

The topic author drafts or revises the narrative text summarizing the evidence found in the literature. American College of Radiology (ACR) staff draft an evidence table based on the analysis of the selected literature. These tables rate the strength of the evidence for all articles included in the narrative text.

The expert panel reviews the narrative text, evidence table, and the supporting literature for each of the topic-variant combinations and assigns an appropriateness rating for each procedure listed in the table. Each individual panel member forms his/her own opinion based on his/her interpretation of the available evidence.

More information about the evidence table development process can be found in the ACR Appropriateness Criteria® Evidence Table Development document (see the "Availability of Companion Documents" field).

Modified Delphi Technique

The appropriateness ratings for each of the procedures included in the Appropriateness Criteria topics are determined using a modified Delphi methodology. A series of surveys are conducted to elicit each panelist's expert interpretation of the evidence, based on the available data, regarding the appropriateness of an imaging or therapeutic procedure for a specific clinical scenario. American College of Radiology (ACR) staff distributes surveys to the panelists along with the evidence table and narrative. Each panelist interprets the available evidence and rates each procedure. The surveys are completed by panelists without consulting other panelists. The ratings are a scale between 1 and 9, which is further divided into three categories: 1, 2, or 3 is defined as "usually not appropriate"; 4, 5, or 6 is defined as "may be appropriate"; and 7, 8, or 9 is defined as "usually appropriate." Each panel member assigns one rating for each procedure per survey round. The surveys are collected and the results are tabulated, de-identified and redistributed after each round. A maximum of three rounds are conducted. The modified Delphi technique enables each panelist to express individual interpretations of the evidence and his or her expert opinion without excessive bias from fellow panelists in a simple, standardized and economical process.

Consensus among the panel members must be achieved to determine the final rating for each procedure. Consensus is defined as eighty percent (80%) agreement within a rating category. The final rating is determined by the median of all the ratings once consensus has been reached. Up to three rating rounds are conducted to achieve consensus.

If consensus is not reached, the panel is convened by conference call. The strengths and weaknesses of each imaging procedure that has not reached consensus are discussed and a final rating is proposed. If the panelists on the call agree, the rating is accepted as the panel's consensus. The document is circulated to all the panelists to make the final determination. If consensus cannot be reached on the call or when the document is circulated, "No consensus" appears in the rating column and the reasons for this decision are added to the comment sections.

Not applicable

A formal cost analysis was not performed and published cost analyses were not reviewed.

Criteria developed by the Expert Panels are reviewed by the American College of Radiology (ACR) Committee on Appropriateness Criteria.

ACR Appropriateness Criteria®

Clinical Condition: Left Lower Quadrant Pain—Suspected Diverticulitis

Variant 1: Typical clinical presentation for diverticulitis, suspected complications or atypical presentations.

Radiologic Procedure	Rating	Comments	RRL*
CT abdomen and pelvis with contrast	9	Oral and/or colonic contrast may be helpful for bowel luminal visualization.
CT abdomen and pelvis without contrast	6
CT abdomen and pelvis without and with contrast	5
MRI abdomen and pelvis without contrast	5		O
MRI abdomen and pelvis without and with contrast	5	See statement regarding contrast in text under "Anticipated Exceptions."	O
X-ray contrast enema	4
US abdomen transabdominal graded compression	4		O
US abdomen transrectal or transvaginal	4		O
X-ray abdomen and pelvis	4
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Note: Abbreviations used in the table are listed at the end of the "Major Recommendations" field.

Summary of Literature Review

Introduction/Background

The most common cause of left lower quadrant pain in adults is acute sigmoid diverticulitis, which is estimated to occur in 20% to 25% of patients with diverticulosis. Appropriate imaging triage for patients with suspected diverticulitis (i.e., left lower quadrant pain) should address two major clinical questions: 1) what are the differential diagnostic possibilities in this clinical situation, and 2) what information is necessary to make a definitive management decision. Some patients with acute diverticulitis may not require any imaging, notably those with typical symptoms of diverticulitis (e.g., left lower quadrant pain and tenderness) without suspected complications or those with a previous history of diverticulitis who present with clinical symptoms of recurrent disease. Many such patients are treated medically without undergoing radiologic examinations, but diverticulitis can be simulated by other acute abdominal disorders. Patients with diverticulitis may require surgery or interventional radiology procedures because of associated complications, including abscesses, fistulas, obstruction, or perforation. As a result, there has been a trend toward greater use of imaging tests to confirm the diagnosis of diverticulitis, evaluate the extent of disease, and detect complications before deciding on appropriate treatment.

Abdominal radiography is of limited value in evaluating diverticulitis unless complications such as free perforation (pneumoperitoneum) or obstruction are suspected. Nuclear medicine imaging has no role in the evaluation of left lower quadrant pain. The role of magnetic resonance imaging (MRI) has not been adequately evaluated, but preliminary data suggest that it may have diagnostic potential in patients with suspected diverticulitis. The imaging test most often used for diagnosing diverticulitis is computed tomography (CT), but graded compression ultrasound (US), barium enema, and MRI have also been used.

Barium Enema

In the past, contrast enema was the primary imaging test for diverticulitis. It currently is performed very uncommonly for this diagnosis. The barium enema has a reported sensitivity of 59% to 90% for diagnosing sigmoid diverticulitis. The examination, however, is limited, as diverticulitis is mainly an extramucosal process and contrast enema only shows the secondary effects of inflammation on the colon and will not show extraluminal abnormalities including abscesses and pericolonic inflammation. Barium enema is also more invasive and is not as sensitive for distant pathology. Although CT has replaced the contrast enema as the initial imaging test for diverticulitis in most patients, the contrast enema may be helpful in some instances as a follow-up study for patients in whom the CT findings cannot unequivocally be used to differentiate diverticulitis from colonic carcinoma, especially if colonoscopy cannot be performed because of narrowing of the colon. When the diagnosis of sigmoid diverticulitis is equivocal (i.e., normal CT scan and clinical presentation of left lower quadrant pain) a contrast enema may sometimes be helpful in excluding the sigmoid colon as the source of the pain.

Computed Tomography

CT is now widely advocated as the imaging test of choice for evaluating patients with suspected sigmoid diverticulitis because of its high sensitivity and specificity and its ability to demonstrate other causes of left lower quadrant pain that mimic diverticulitis. It is widely available, reproducible, and less invasive than the contrast enema, and it has a reported sensitivity of 79% to 99%. CT also has a major role for determining disease extent; this assessment is rarely possible with contrast enema. By revealing the presence and extent of abscess formation, CT facilitates selection of patients for medical rather than surgical therapy and to determine if hospitalization is required. When abscesses are present, it has been shown that US- and CT-guided percutaneous drainage of abscess collections can eliminate multistage operative procedures and, in some cases, can eliminate the need for surgery entirely. Finally, CT can demonstrate extracolonic diseases (e.g., genitourinary and gynecologic abnormalities) which have a similar clinical presentation. It reveals the alternative diagnosis of epiploic appendagitis which can clinically present similarly. The imaging of premenopausal women with acute pelvic pain is discussed in the NGC summary of the ACR Appropriateness Criteria® guideline Acute Pelvic Pain in the Reproductive Age Group.

A variety of contrast media have been used for CT to optimize the sensitivity and specificity of the examination, including oral and intravenous contrast agents and rectally administered contrast or air, although regardless of the technique used the accuracy is high.

Ultrasound

Although most of the reported experience has been with CT, transabdominal sonography has been advocated as an alternative technique for evaluating patients with suspected diverticulitis. Graded compression sonography is reported to have a sensitivity of 77% to 98% and a specificity of 80% to 99% in diagnosing diverticulitis. One meta-analysis study suggested that graded compression US and CT are both effective initial diagnostic tools but that CT is more likely to reveal alternative diagnoses for left lower quadrant pain. Some investigators advocate the selective use of transrectal sonography to improve detection of diverticulitis if the findings on transabdominal sonography are negative or equivocal. In one study, the sensitivity of US was lower than that of CT when correlated with histopathology that is thought to be related to complicated diverticulitis, whereas CT was better in showing extraluminal air and abscesses. Transvaginal sonography is of particularly value when left lower quadrant pain and fever occur in women of childbearing age. In this setting, gynecologic processes such as ectopic pregnancy and pelvic inflammatory disease are also important diagnostic considerations. Sonography is therefore an excellent choice for the initial imaging of this patient population, because it is more sensitive than CT or contrast enemas in depicting gynecologic abnormalities that cause left lower quadrant pain. However, graded compressions sonography for diverticulitis is a technique that is highly operator dependent, requiring a high level of expertise. US for diverticulitis is not widely used especially in the United States. Sonography is also much more dependent on body habitus than CT or MR — especially for imaging of a relatively posterior structure such as the descending and sigmoid colon.

Magnetic Resonance Imaging

The role of MRI in the setting of left lower quadrant pain has not been adequately evaluated, but preliminary data suggest that it may have diagnostic potential in patients with suspected diverticulitis. The findings for MRI are similar to those for CT, including demonstration of complications of diverticulitis; however, MRI, like US, has lower sensitivity for detecting small amounts of extraluminal air than CT. There is a potential role for MRI in imaging younger patients with recurrent episodes of known or suspected diverticulitis in order to reduce radiation exposure, although it has not been systematically evaluated.

Finally, it should be recognized that a perforated colon cancer can mimic both the clinical and radiographic findings of diverticulitis. CT findings that suggest colon cancer rather than diverticulitis include the presence of pericolonic lymphadenopathy (1 cm), with or without pericolonic edema. When there are inflammatory changes, edema in the root of the sigmoid mesentery, and no pericolonic lymphadenopathy adjacent to a segment of thickened colon wall, the most likely diagnosis is diverticulitis. Patients with equivocal CT findings of diverticulitis should undergo a follow-up examination of the colonic mucosa after the acute symptoms have resolved. Either a colonoscopy or barium enema could be performed to differentiate diverticulitis from a perforated colon cancer in these patients. Quantitative CT perfusion measurements have been shown to differentiate cancer from diverticulitis. Patients with cancer have the highest blood volume, blood flow, and permeability and the shortest transit time.

Summary

• CT is now widely advocated as the primary imaging test for evaluating acute sigmoid diverticulitis because of its high sensitivity and specificity, its ability to determine the presence and extent of disease that might warrant percutaneous catheter drainage or surgery, and its ability to show the presence of extracolonic disease in these patients.
• Abdominal radiography and barium enema play a far less significant role and should not be used as the primary modality for the diagnosis.
• US, although effective when performed by experienced users, is used less widely in the United States and has limitations in the setting of complicated diverticulitis.
• MRI, while potentially effective in the diagnosis of diverticulitis, is not widely used for this purpose at present. No large prospective studies to the Panel's knowledge have compared MRI with CT in the diagnosis of diverticulitis.

Anticipated Exceptions

Nephrogenic systemic fibrosis (NSF) is a disorder with a scleroderma-like presentation and a spectrum of manifestations that can range from limited clinical sequelae to fatality. It appears to be related to both underlying severe renal dysfunction and the administration of gadolinium-based contrast agents. It has occurred primarily in patients on dialysis, rarely in patients with very limited glomerular filtration rate (GFR) (i.e., <30 mL/min/1.73 m²), and almost never in other patients. There is growing literature regarding NSF. Although some controversy and lack of clarity remain, there is a consensus that it is advisable to avoid all gadolinium-based contrast agents in dialysis-dependent patients unless the possible benefits clearly outweigh the risk, and to limit the type and amount in patients with estimated GFR rates <30 mL/min/1.73 m². For more information, please see the American College of Radiology (ACR) Manual on Contrast Media (see the "Availability of Companion Documents" field).

Abbreviations

• CT, computed tomography
• MR, magnetic resonance
• MRI, magnetic resonance imaging
• US, ultrasound

Relative Radiation Level Designations

Relative Radiation Level*	Adult Effective Dose Estimate Range	Pediatric Effective Dose Estimate Range
O	0 mSv	0 mSv
	<0.1 mSv	<0.03 mSv
	0.1-1 mSv	0.03-0.3 mSv
	1-10 mSv	0.3-3 mSv
	10-30 mSv	3-10 mSv
	30-100 mSv	10-30 mSv
*RRL assignments for some of the examinations cannot be made, because the actual patient doses in these procedures vary as a function of a number of factors (e.g., region of the body exposed to ionizing radiation, the imaging guidance that is used). The RRLs for these examinations are designated as "Varies".

Algorithms were not developed from criteria guidelines.

The recommendations are based on analysis of the current literature and expert panel consensus.

Selection of appropriate radiologic imaging procedures for evaluation and diagnosis of patients with left lower quadrant pain, suspected diverticulitis

Gadolinium-based Contrast Agents

Nephrogenic systemic fibrosis (NSF) is a disorder with a scleroderma-like presentation and a spectrum of manifestations that can range from limited clinical sequelae to fatality. It appears to be related to both underlying severe renal dysfunction and the administration of gadolinium-based contrast agents. It has occurred primarily in patients on dialysis, rarely in patients with very limited glomerular filtration rate (GFR) (i.e., <30 mL/min/1.73 m²), and almost never in other patients. Although some controversy and lack of clarity remain, there is a consensus that it is advisable to avoid all gadolinium-based contrast agents in dialysis-dependent patients unless the possible benefits clearly outweigh the risk, and to limit the type and amount in patients with estimated GFR rates <30 mL/min/1.73 m². For more information, please see the American College of Radiology (ACR) Manual on Contrast Media (see the "Availability of Companion Documents" field).

Relative Radiation Level (RRL)

Potential adverse health effects associated with radiation exposure are an important factor to consider when selecting the appropriate imaging procedure. Because there is a wide range of radiation exposures associated with different diagnostic procedures, a relative radiation level indication has been included for each imaging examination. The RRLs are based on effective dose, which is a radiation dose quantity that is used to estimate population total radiation risk associated with an imaging procedure. Patients in the pediatric age group are at inherently higher risk from exposure, both because of organ sensitivity and longer life expectancy (relevant to the long latency that appears to accompany radiation exposure). For these reasons, the RRL dose estimate ranges for pediatric examinations are lower as compared to those specified for adults. Additional information regarding radiation dose assessment for imaging examinations can be found in the ACR Appropriateness Criteria® Radiation Dose Assessment Introduction document (see the "Availability of Companion Documents" field).

The American College of Radiology (ACR) Committee on Appropriateness Criteria and its expert panels have developed criteria for determining appropriate imaging examinations for diagnosis and treatment of specified medical condition(s). These criteria are intended to guide radiologists, radiation oncologists, and referring physicians in making decisions regarding radiologic imaging and treatment. Generally, the complexity and severity of a patient's clinical condition should dictate the selection of appropriate imaging procedures or treatments. Only those examinations generally used for evaluation of the patient's condition are ranked. Other imaging studies necessary to evaluate other co-existent diseases or other medical consequences of this condition are not considered in this document. The availability of equipment or personnel may influence the selection of appropriate imaging procedures or treatments. Imaging techniques classified as investigational by the U.S. Food and Drug Administration (FDA) have not been considered in developing these criteria; however, study of new equipment and applications should be encouraged. The ultimate decision regarding the appropriateness of any specific radiologic examination or treatment must be made by the referring physician and radiologist in light of all the circumstances presented in an individual examination.

An implementation strategy was not provided.

Not applicable: The guideline was not adapted from another source.

The American College of Radiology (ACR) provided the funding and the resources for these ACR Appropriateness Criteria®.

Committee on Appropriateness Criteria, Expert Panel on Gastrointestinal Imaging

Panel Members: Frank H. Miller, MD (Principal Author); Max P. Rosen, MD, MPH (Panel Chair); Tasneem Lalani, MD (Panel Vice-chair); Mark E. Baker, MD; Michael A. Blake, MB, BCh; Brooks D. Cash, MD; Jeff L. Fidler, MD; Frederick L. Greene, MD; Nicole M. Hindman, MD; Bronwyn Jones, MD; Douglas S. Katz, MD; Harmeet Kaur, MD; Aliya Qayyum, MD; William C. Small, MD, PhD; Gary S. Sudakoff, MD; Mark Tulchinsky, MD; Vahid Yaghmai, MD, MS; Gail M. Yarmish, MD; Judy Yee, MD

Not stated

This is the current release of the guideline.

This guideline updates a previous version: Miller FH, Bree RL, Rosen MP, Foley WD, Gay SB, Grant TH, Heiken JP, Huprich JE, Lalani T, Sudakoff GS, Greene FL, Rockey DC, Expert Panel on Gastrointestinal Imaging. ACR Appropriateness Criteria® left lower quadrant pain. [online publication]. Reston (VA): American College of Radiology (ACR); 2008. 5 p.

The appropriateness criteria are reviewed biennially and updated by the panels as needed, depending on introduction of new and highly significant scientific evidence.

Electronic copies: Available in Portable Document Format (PDF) from the American College of Radiology (ACR) Web site.

Print copies: Available from the American College of Radiology, 1891 Preston White Drive, Reston, VA 20191. Telephone: (703) 648-8900.

The following are available:

• ACR Appropriateness Criteria®. Overview. Reston (VA): American College of Radiology; 2 p. Electronic copies: Available in Portable Document Format (PDF) from the American College of Radiology (ACR) Web site.
• ACR Appropriateness Criteria®. Literature search process. Reston (VA): American College of Radiology; 1 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.
• ACR Appropriateness Criteria®. Evidence table development. Reston (VA): American College of Radiology; 4 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.
• ACR Appropriateness Criteria®. Radiation dose assessment introduction. Reston (VA): American College of Radiology; 2 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.
• ACR Appropriateness Criteria® Manual on contrast media. Reston (VA): American College of Radiology; 90 p. Electronic copies: Available in PDF from the ACR Web site.

None available

This summary was completed by ECRI on March 19, 2001. The information was verified by the guideline developer on March 29, 2001. This NGC summary was updated by ECRI on November 11, 2004. The information was verified by the guideline developer on December 21, 2004. This summary was updated by ECRI on March 21, 2006. This summary was updated by ECRI Institute on June 23, 2009. This summary was updated by ECRI Institute on January 13, 2011 following the U.S. Food and Drug Administration (FDA) advisory on gadolinium-based contrast agents. This NGC summary was updated by ECRI Institute on February 22, 2012.

Instructions for downloading, use, and reproduction of the American College of Radiology (ACR) Appropriateness Criteria® may be found on the ACR Web site .