Visibility of Normal Appendix on CT, MRI, and Sonography: A Systematic Review and Meta-Analysis

Time to improve the management of patients with suspected acute appendicitis: a retrospective study

PURPOSE

Preoperative imaging is now recommended in patients with suspected acute appendicitis (AA) by the World Society of Emergency Surgery. Our aims were (i) to describe our local practice and (ii) to evaluate the efficiency of performing ultrasound (US) and/or computed tomography (CT) by assessing management failure, specificity and sensitivity, and length of stay in the emergency department (ED).

METHODS

This single-center retrospective study included all patients who underwent US or CT for the management of suspected AA. Patients were included if they were admitted to the ED in February or June between 2012 and 2021.

RESULTS

The study included 339 patients. US was performed in 278 patients (82%), of whom 91 also had a second-line CT (31.3%). There was a significant increase in the rate of CT over the inclusion period. Three percent (3%) of the patients had management failure and a higher age and CT or US + CT were significantly associated with the risk of management failure. Length of stay in the ED increased significantly when a second-line CT was performed. The sensitivity and specificity of US were 84.8% and 93.2%, respectively. Sensitivity was significantly different from CT (100%, p = 0.03) but not specificity (87.9%, p = 0.29). Both US and CT results were more likely to be considered for further management if positive. The vast majority of patients with negative or inconclusive results were admitted in surgical wards or underwent a second-line examination.

CONCLUSION

If available in the hospital together with CT, US should probably be performed systematically and as a first-line examination in patients with suspected acute appendicitis.

Introducing the ratio of cross diameters of the appendix for ultrasound diagnosis of acute appendicitis can significantly increase specificity

PURPOSE

To validate whether the introduction of the ratio of the cross diameters on the transverse section of the appendix (RATIO) ≤ 1.18 is useful for improving the ultrasound diagnosis of acute appendicitis (AA).

METHODS

Data from 220 patients with AA and 110 patients with a normal appendix were retrospectively studied. The RATIO ≤ 1.18, maximal outer diameter (MOD) > 6 mm, and a combination of RATIO ≤ 1.18 and MOD > 6 mm were used for predicting AA. The area under the receiver operating characteristic curve (AUC), sensitivity, specificity, positive and negative predictive values (PPV and NPV) were calculated.

RESULTS

The RATIO ≤ 1.18, MOD > 6 mm, and a combination of RATIO ≤ 1.18 and MOD > 6 mm for predicting AA showed a sensitivity of 90, 100, and 90%; specificity of 79.1, 27.3, and 88.2%; and AUC of 0.845, 0.636, and 0.891, respectively. When comparing the outcomes between MOD > 6 mm and a combination of MOD > 6 mm and RATIO ≤ 1.18, the specificity and PPV increased from 27.3 to 88.2% and 73.3 to 93.8%, respectively (all P < 0.0001). The sensitivity and NPV decreased from 100 to 90% and 100 to 81.5%, respectively (all P < 0.0001). The AUC increased from 0.636 to 0.891 (P < 0.0001). When comparing the AUC of MOD > 6 mm, and a combination of RATIO ≤ 1.18 and MOD > 6 mm for predicting AA with the AUC in a previous study, there were no significant differences between each other (all P > 0.05).

CONCLUSION

Introducing the RATIO ≤ 1.18 for the evaluation of AA can improve the diagnostic performance and significantly increase specificity.

Added value of ratio of cross diameters of the appendix in ultrasound diagnosis of acute appendicitis

BACKGROUND

The maximum outer diameter (MOD) of the appendix is an essential parameter for diagnosing acute appendicitis, but there is space for improvement in ultrasound (US) diagnostic performance.

AIM

To investigate whether combining the ratio of the cross diameters (RATIO) of the appendix with MOD of the appendix can enhance the diagnostic performance of acute appendicitis.

METHODS

A retrospective study was conducted, and medical records of 233 patients with acute appendicitis and 112 patients with a normal appendix were reviewed. The MOD and RATIO of the appendix were calculated and tested for their diagnostic performance of acute appendicitis, both individually and in combination.

RESULTS

The RATIO for a normal appendix was 1.32 ± 0.16, while for acute appendicitis it was 1.09 ± 0.07. The cut-off value for RATIO was determined to be ≤ 1.18. The area under the receiver operating characteristic curve (AUC) for diagnosing acute appendicitis using RATIO ≤ 1.18 and MOD > 6 mm was 0.870 and 0.652, respectively. There was a significant difference in AUC between RATIO ≤ 1.18 and MOD > 6 mm (P < 0.0001). When comparing the combination of RATIO ≤ 1.18 and MOD > 6 mm with MOD > 6 mm alone, the combination showed increased specificity, positive predictive value (PPV), and AUC. However, the sensitivity and negative predictive value decreased.

CONCLUSION

Combining RATIO of the appendix ≤ 1.18 and MOD > 6 mm can significantly improve the specificity, PPV, and AUC in the US diagnosis of acute appendicitis.

Rapid MRI Abdomen for Assessment of Clinically Suspected Acute Appendicitis in the General Adult Population: a Systematic Review

OBJECTIVES

To perform a systematic review on the use of magnetic resonance imaging (MRI) of the abdomen to evaluate clinically suspected appendicitis in the general adult population. We examined the diagnostic accuracy, the reported trends of MRI use, and the factors that affect the utility of MRI abdomen, including study duration and cost-benefits.

METHODS

We conducted a systematic literature search on PubMed, MEDLINE, Embase, Web of Science, and Cochrane Library databases. We enrolled primary studies investigating the use of MRI in diagnosing appendicitis in the general adult population, excluding studies that predominantly reported on populations not representative of typical adult appendicitis presentations, such as those focusing on paediatric or pregnant populations.

RESULTS

Twenty-seven eligible primary studies and 6 secondary studies were included, totaling 2,044 patients from eight countries. The sensitivity and specificity of MRI for diagnosing appendicitis were 96% (95% CI: 93-97%) and 93% (95% CI: 80-98%), respectively. MRI can identify complicated appendicitis and accurately propose alternative diagnoses. The duration of MRI protocols in each primary study ranged between 2.26 and 30 minutes, and only one study used intravenous contrast agents in addition to the non-contrast sequences. Decision analysis suggests significant benefits for replacing computed tomography (CT) with MRI and a potential for cost reduction. Reported trends in MRI usage showed minimal utilisation in diagnostic settings even when MRI was available.

CONCLUSIONS

MRI accurately diagnoses appendicitis in the general adult population and improves the identification of complicated appendicitis or alternative diagnoses compared to other modalities using a single, rapid investigation.

Appendiceal neoplasms: Suspected findings and reports of 14 cases

Background

Neoplastic lesions of the vermiform appendix are still considered to be rare, some studies suggest that appendix cancer may be on the rise, with an estimated incidence of 0.08-0.1% of all appendiceal specimens. The lifetime incidence of malignant appendiceal tumors ranges from 0.2 to 0.5%.

Patients and Methods

Our study is applied at the Department of General Surgery at tertiary training and research hospital; 14 patients who had appendectomy or right hemicolectomy between December 2015 and April 2020 were evaluated.

Results

The mean age of the patients was 52.3 ± 15.1 (range, 26-79) years. Gender of the patients were: five (35.7%) men and nine (64.3%) women. The clinical diagnosis was appendicitis without suspected findings in 11 (78.6%), appendicitis with suspected findings (appendiceal mass, etc.) in three (21.4%) of the patients, and there is no patient with asymptomatic or other rare findings. Surgeries applied for the patients were: nine (64.3%) underwent open appendectomy, four (28.6%) underwent laparoscopic appendectomy, and one (7.1%) underwent open right hemicolectomy. Histopathologic results were as follows: five (35.7%) neuroendocrine neoplasm, eight (57.1%), noninvasive mucinous neoplasm, and one (7.1%) adenocarcinoma.

Conclusion

While diagnosis and management of appendiceal pathology, surgeons should be familiar with suspected findings of appendiceal tumors and discuss them with patients to the possibility of histopathologic results.

Update on acute appendicitis: Typical and untypical findings

Acute appendicitis is the most common indication for emergency abdominal surgery throughout the world and a common reason for consultation in emergency departments. In recent decades, diagnostic imaging has played a fundamental role in identifying acute appendicitis, helping to reduce the rate of blind laparotomies and hospital costs. Given the results of clinical trials supporting the use of antibiotic therapy over surgical treatment, radiologists need to know the diagnostic criteria for complicated acute appendicitis to be able to recommend the best treatment option. This review aims not only to define the diagnostic criteria for appendicitis in different imaging modalities (ultrasonography, computed tomography, and magnetic resonance imaging), but also to explain the diagnostic protocols, atypical presentations, and other conditions that can mimic appendicitis.

Intestinal ultrasound detects an increased diameter and submucosal layer thickness in the appendix of patients with ulcerative colitis compared to healthy controls - a prospective cohort study

BACKGROUND

Increasing evidence suggests that appendicectomy as alternative treatment for ulcerative colitis (UC), especially in patients with histopathological appendiceal inflammation. Intestinal ultrasound (IUS) is a non-invasive diagnostic modality to characterise appendiceal inflammation.

AIMS

To assess appendiceal IUS characteristics in UC patients and compare findings to healthy controls (HC).

METHODS

In this prospective study, appendiceal IUS was performed in consecutive UC patients with active (A; n = 35) or quiescent (Q; n = 30) disease and in HC (n = 30). Transverse appendiceal diameter (TAD) and additional IUS parameters (bowel wall thickness, submucosal layer thickness and colour Doppler signal) were assessed.

RESULTS

The appendix was visualised in 41/65 UC patients (63.1%; A vs. Q: 23/35 vs. 18/30, p = 0.67) and 18/30 (60%) HC. UC patients had a higher TAD (A: 5.5 mm, Q: 5.0 mm, HC: 4.3 mm; A-HC p < 0.01; Q-HC p = 0.01, A-Q p = ns) and submucosal layer thickness (A: 1.0 mm, Q: 1.0 mm, HC: 0.7 mm; A-HC p < 0.01, Q-HC: p = 0.01, A-Q: p = ns) when compared to HC. A TAD ≥6 mm corresponding to an ultrasonographic suspicion of acute appendicitis was mainly reported in A-UC patients (A: 43%; Q: 6%; HC: 0%, p = 0.01) and occurred irrespective of disease extent. However, none of the patients had a clinical suspicion of acute appendicitis.

CONCLUSION

A TAD ≥6 mm was predominantly seen in A-UC. TAD was higher in UC patients compared to HC irrespective of disease activity and was characterised by an increased submucosal layer thickness. IUS therefore has the potential to identify UC patients with appendiceal inflammation.

Predictive value of immature granulocyte in the diagnosis of acute complicated appendicitis

INTRODUCTION

The goal in appendicitis is early diagnosis and early treatment. Complications develop as treatment is delayed. Therefore, there is a need for fast, low-cost markers that can be diagnosed earlier. The aim of this study is to show the effectiveness of immature granulocyte (IG) level in determining the complication of acute appendicitis.

METHOD

In this retrospective cross-sectional study, 99 patients with acute appendicitis and 41 control groups were included in the study. Acute appendicitis patients were divided into two groups as acute simple appendicitis(n = 65) and acute complicated appendicitis(n = 34). In all groups, demographic data, immature granulocyte (IG) count(x103/μL), IG ratio (IG%), white blood cell (WBC), polymorphonuclear leukocytes (PNL), lymphocyte, monocyte, platelet, mean platelet volume (MPV), ferritin levels were recorded. The blood analyses were performed the Mindray BC6800 automated hematology analyzer using standard laboratory protocols. All statistical testing was undertaken using IBM SPSS Statistics for Mac.

RESULTS

Compared to the acute simple appendicitis, acute complicated appendicitis patients had significantly higher levels WBC, PNL, monocyte, IG count, and IG% (p = 0.009, p = 0047, p = 0.001, p = 0.018; respectively) while there was no significant difference in ferritin between groups (p = 0.49). In the ROC analysis, AUC value was found for IG count and IG% (0.893 and 0.725, cut-off 0.005 and 0.05; respectively) for acute appendicitis. The negative predictive value of IG for Acute Appendicitis was 85% and was the same as that of WBC. In acute complicated appendicitis, the AUC for IG and IG% was 0.796 (cut-off 0.02) and 0.693 (cut-off 0.2), respectively. Positive Likelihood Ratio (+LR; 2.1) value of IG was found higher than other complete blood count (CBC) tests.

CONCLUSION

The IG count is test with fast, more predictive value than another CBC tests, and without cost in the early diagnosis of acute complicated appendicitis. It is strong negative predictive test for Acute Appendicitis disease.

The Dynamics of Inflammatory Markers in Patients with Suspected Acute Appendicitis

Background: Laboratory tests of inflammatory mediators are routinely used in the diagnosis of acute appendicitis (AA). The aim of this study was to evaluate the differences of dynamics of inflammatory markers of the blood in patients with suspected acute appendicitis between complicated AA (CAA), non-complicated AA (NAA), and when AA was excluded (No-AA). Methods: This was a retrospective analysis of prospectively collected data of patients presented to the Emergency Department (ER) of a tertiary hospital center during a three-year period. All patients suspected of acute appendicitis were prospectively registered from 1 January 2016 to 31 December 2018. The dynamics of inflammatory markers of the blood between different types of AA (No-AA, NAA or CAA) during different periods of time are presented. Results: A total of 453 patients were included in the study, with 297 patients in the No-AA group, 99 in the NAA group, and 57 in the CAA group. White blood cell (WBC) count in the No-AA decreased with time, with a statistically significant difference between the <8 h and 25-72 h group. The neutrophils (NEU) percentage decreased in the No-AA group and was statistically significantly different between the <8 h and 25-72 h and <8 h and >72 h groups. C-reactive protein (CRP) increased significantly in the No-AA group throughout all time intervals, and from the first 24 h to the 25-72 h in the NAA and CAA groups. There was a statistically significant difference between the WBC count between No-AA, NAA, and No-AA and CAA groups during the first 24 and 24-48 h. There was a statistically significant difference between NEU percentage and LYMP percentage and in the NEU/LYMP ratio between No-AA and CAA groups through all time periods. CRP was significantly higher in the first 24 h in the CAA than in the No-AA group, and in the 24-48 h in the CAA group than in the No-AA and NAA groups. The linear logistic regression model, involving inflammatory mediators and clinical characteristics, showed mediocre diagnostic accuracy for diagnosing AA with an AUC of 0.737 (0.671-0.802). Conclusions: Increasing concentrations of inflammatory markers are more characteristic in CAA patients than in No-AA during the first 48 h after onset of the disease. A combination of laboratory tests with clinical signs and symptoms has a mediocre diagnostic accuracy in suspecting AA.

Diagnosis and Management of Acute Appendicitis in Adults: A Review

IMPORTANCE

Acute appendicitis is the most common abdominal surgical emergency in the world, with an annual incidence of 96.5 to 100 cases per 100 000 adults.

OBSERVATIONS

The clinical diagnosis of acute appendicitis is based on history and physical, laboratory evaluation, and imaging. Classic symptoms of appendicitis include vague periumbilical pain, anorexia/nausea/intermittent vomiting, migration of pain to the right lower quadrant, and low-grade fever. The diagnosis of acute appendicitis is made in approximately 90% of patients presenting with these symptoms. Laparoscopic appendectomy remains the most common treatment. However, increasing evidence suggests that broad-spectrum antibiotics, such as piperacillin-tazobactam monotherapy or combination therapy with either cephalosporins or fluroquinolones with metronidazole, successfully treats uncomplicated acute appendicitis in approximately 70% of patients. Specific imaging findings on computed tomography (CT), such as appendiceal dilatation (appendiceal diameter ≥7 mm), or presence of appendicoliths, defined as the conglomeration of feces in the appendiceal lumen, identify patients for whom an antibiotics-first management strategy is more likely to fail. CT findings of appendicolith, mass effect, and a dilated appendix greater than 13 mm are associated with higher risk of treatment failure (≈40%) of an antibiotics-first approach. Therefore, surgical management should be recommended in patients with CT findings of appendicolith, mass effect, or a dilated appendix who are fit for surgery, defined as having relatively low risk of adverse outcomes or postoperative mortality and morbidity. In patients without high-risk CT findings, either appendectomy or antibiotics can be considered as first-line therapy. In unfit patients without these high-risk CT findings, the antibiotics-first approach is recommended, and surgery may be considered if antibiotic treatment fails. In unfit patients with high-risk CT findings, perioperative risk assessment as well as patient preferences should be considered.

CONCLUSIONS AND RELEVANCE

Acute appendicitis affects 96.5 to 100 people per 100 000 adults per year worldwide. Appendectomy remains first-line therapy for acute appendicitis, but treatment with antibiotics rather than surgery is appropriate in selected patients with uncomplicated appendicitis.

Role of circulating fibrocytes in the diagnosis of acute appendicitis

Background

Improved diagnostic biomarkers are required for acute appendicitis. The circulating fibrocyte percentage (CFP) is increased in inflammatory states, but has not been studied in acute appendicitis. This study aimed to determine CFP in acute appendicitis and compare diagnostic accuracy with standard serological biomarkers.

Methods

A prospective cohort study was carried out between June 2015 and February 2016 at University Hospital Limerick. The CFP was determined by dual‐staining peripheral venous samples for CD45 and collagen I using fluorescence‐activated cell sorting, and correlated with histopathological diagnoses. The accuracy of CFP in determining histological acute appendicitis was characterized and compared with the white cell count, C‐reactive protein concentration, neutrophil count, lymphocyte count and neutrophil : lymphocyte ratio.

Results

Of 95 adults recruited, 15 were healthy individuals and 80 had suspected appendicitis at presentation. Forty‐six of these 80 patients had an appendicectomy, of whom 34 had histologically confirmed appendicitis. The CFP was statistically higher in patients with pathologically proven acute appendicitis than in healthy controls (median 6·1 (i.q.r. 1·6–11·6) versus 2·3 (0·9–3·4) per cent respectively; P = 0·008). The diagnostic accuracy of CFP, as determined using the area under the receiver operating characteristic (ROC) curve, was similar to that of standard biomarkers. In multinomial regression analysis, only raised CFP was retained as an independent prognostic determinant of acute appendicitis (odds ratio 1·57, 95 per cent c.i. 1·05 to 2·33; P = 0·027).

Conclusion

The CFP is increased in histologically confirmed acute appendicitis and is as accurate as standard serological biomarkers in terms of diagnosis.

Value Assessment of Evolving Pediatric Appendicitis Imaging Strategies Between 2004 and 2018

OBJECTIVE

To assess diagnostic imaging utilization and the proportion of negative appendectomies for pediatric appendicitis at US children's hospitals between 2004 and 2018.

METHODS

This was a retrospective study using data from the Pediatric Health Information System (PHIS) database. Pediatric patients (age: 0-17 years) who underwent an appendectomy at one of 32 children's hospitals from January 1, 2004, through September 30, 2018, were included. Patients were identified based on International Classification of Diseases, 9th revision and International Classification of Diseases, 10th revision procedure codes. Patient demographics, imaging performed, and the frequency of negative appendectomy were analyzed.

RESULTS

The final study population consisted of 104,033 children. From 2004 to 2018, CT utilization decreased from 56.8% (2,951 of 5,198) to 18.6% (1,201 of 6,455; P < .001). Ultrasound utilization increased from 26.4% (1,371 of 5,198) to 63.4% (4,093 of 6,455; P < .001). Radiography utilization remained stable at 16.7% (870 of 5,198) and 15.8% (1,018 of 6,455; P = .160). MRI use increased from 0.1% (6 of 5,198) to 2.2% (143 of 6,455; P < .001). During the study period, the negative appendectomy rate slightly decreased, from 3.74% (4,742 of 126,778 in 2004-2011) to 3.14% (4,258 of 135,561 in 2012-2018; P < .001).

CONCLUSION

There has been a shift in imaging of children with appendicitis over 15 years in the United States, because the use of CT has decreased and ultrasound use has increased. This shift has likely added value to the health care system without adversely affecting outcomes (negative appendectomy rate).

Imaging of appendicitis: Tips and tricks

Acute appendicitis is one of the most common surgical emergencies worldwide. Over the past 30 years, imaging has become central to the diagnosis of appendicitis, reducing both negative appendicectomy rate and healthcare expenses. Appendicitis can be challenging in many ways for radiologists with various clinical presentations, complications and differential diagnoses. The aim of this review is to present a step-by-step reasoning with key findings, tips and tricks leading to the diagnosis of appendicitis and its complications. The first steps are with the use of the appropriate imaging modality (US, CT and MRI) to locate the appendix in abdominal cavity and to identify the features of appendicitis and its complications through specific imaging signs. The next steps are to eliminate an unusual morphology of the appendix that may simulate acute appendicitis and to recognize an unusual imaging presentation of appendicitis. Then, to corroborate the diagnosis of appendicitis, the last step is to rule out any differential diagnoses mainly from the genitourinary and gastrointestinal tracts. Following these steps can help to accurately diagnose appendicitis and its complications.