Revisiting the Appendiceal Diameter via Ultrasound for the Diagnosis of 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.

Ultrasound Assessment in Children With Suspected Appendicitis: Time to Revise Diagnostic Criteria: A Prospective Cohort Study

Background: Although ultrasound is considered the gold standard for the evaluation of children with suspected appendicitis, there is still much debate about the most accurate ultrasound findings. The purpose of this study was to define the best ultrasound signs that could ultimately improve the diagnostic accuracy of ultrasound for diagnosing pediatric acute appendicitis, and to differentiate between simple appendicitis and complicated appendicitis. Patients and Methods: After approval by our Institutional Review Board, a prospective study was carried out from January 1, 2022, to July 31, 2023, in a pediatric emergency department. We included all patients aged under 14 years with suspected appendicitis and ultrasound-visualized appendix. Results: A total of 550 patients presented with suspected appendicitis during the study period. Of these children, 411 had an ultrasound-visualized appendix. Our patients' mean age was 9.4 years. The best positive predictive value of ultrasound was found for appendiceal diameter ≥7.5 mm. The combination of an appendiceal diameter <6 mm and the lack of peri-appendiceal free fluid on ultrasound rules out the diagnosis of appendicitis. The best diagnostic accuracy of ultrasound, which was 92%, was achieved for appendix diameters ≥6.5 mm. The sonographic sign giving the best ultrasound accuracy for diagnosing complicated appendicitis was an appendix diameter ≥9 mm. Conclusions: In conclusion, our present study demonstrated that appendiceal diameter ≥6.5 mm is the gold standard for diagnosing appendicitis in pediatric patients. The combination of an appendiceal diameter <6 mm and the lack of peri-appendiceal free fluid on ultrasound would rule out appendicitis.

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.

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.

The utility of sonographic signs to diagnose simple and complicated appendicitis in children

BACKGROUND

Acute appendicitis is classified into simple (SA) and complicated (CA). Ultrasound scans (USS) can be useful in clinically equivocal cases, by visualising primary and secondary signs. This study explores the utility of sonographic signs to diagnose and differentiate appendicitis in children.

METHODS

Single-centre retrospective cohort study over a 2-year period. Consecutive USS for suspected appendicitis were included; sonographic signs were extracted from standardised institutional worksheets. USS results were compared with pre-defined intraoperative criteria for SA and CA, confirmed with histological analysis. Data are reported as median [interquartile range], percentages (number), area under the curve (AUC), conventional diagnostic formulae and adjusted odds ratios following multiple logistic regression (p < 0.05 considered significant).

RESULTS

A total of 934 USS were included, with median age 10.7 [8.0-13.4] years, majority were female (54%). One quarter (n = 226) had SA, 12% (n = 113) had CA, 61% (n = 571) had no appendectomy and 3% (n = 24) had negative appendicectomy. Appendix visualisation rate on USS was 61% (n = 569), with 62% (n = 580) having a conclusive report. Sonographic signs suggesting appendicitis included an appendiceal diameter > 7 mm (AUC 0.92, [95% CI: 0.90-0.94]), an appendicolith (p = 0.003), hyperaemia (p = 0.001), non-compressibility (p = 0.029) and no luminal gas (p = 0.004). Secondary sonographic signs included probe tenderness (p < 0.001) and peri-appendiceal echogenic fat (p < 0.001). Sonographic signs suggesting CA over SA comprised a diameter > 10.1 mm (AUC 0.63, [95% CI: 0.57-0.69]), an appendicolith (p = 0.003) and peri-appendiceal fluid (p = 0.004).

CONCLUSION

Presence of specific sonographic signs can aid diagnosis and differentiation of simple and complicated appendicitis in children.

Refining sonographic criteria for paediatric appendicitis: combined effects of age-based appendiceal size and secondary findings

Objective

Appendiceal diameter is a primary sonographic determinant of paediatric appendicitis. We sought to determine if the diagnostic performance of outer appendiceal diameter differs based on age or with the addition of secondary sonographic findings.

Methods

We retrospectively reviewed patients aged less than 19 years who presented to the Boston Children’s Hospital ED and had an ultrasound (US) for the evaluation of appendicitis between November 2015 and October 2018. Our primary outcome was the presence of appendicitis. We analysed the cases to evaluate the optimal outer appendiceal diameter as a predictor for appendicitis stratified by age (<6, 6 to <11, 11 to <19 years), and with the addition of one or more secondary sonographic findings.

Results

Overall, 945 patients met criteria for inclusion, of which 43.9% had appendicitis. Overall, appendiceal diameter as a continuous measure demonstrated excellent test performance across all age groups (area under the curve (AUC) >0.95) but was most predictive of appendicitis in the youngest age group (AUC=0.99 (0.98–1.00)). Although there was no significant difference in optimal diameter threshold between age groups, both 7- and 8-mm thresholds were more predictive than 6 mm across all groups (p<0.001). The addition of individual (particularly appendicolith or echogenic fat) or combinations of secondary sonographic findings increased the diagnostic value for appendicitis above diameter alone.

Conclusions

Appendiceal diameter as a continuous measure was more predictive of appendicitis in the youngest group. Across all age groups, the optimal diameter threshold was 7 mm for the diagnosis of paediatric appendicitis. The addition of individual or combination secondary sonographic findings increases diagnostic performance.

Predictors for Acute Appendicitis in Children

BACKGROUND

Acute appendicitis in children is the most common condition requiring urgent evaluation and surgery in the emergency department. At times, despite the appendix being seen on ultrasound (US), there can be discrepancy as to whether a patient has clinical appendicitis. Secondary findings suggestive of appendicitis can be helpful in identifying and evaluating these children.

OBJECTIVE

The aim of this study was to determine if specific US findings and/or laboratory results are predictive of appendicitis in children with a visualized appendix on US.

METHODS

A prospective study was conducted on children (birth to 18 years) presenting to the pediatric emergency department with suspected appendicitis who underwent right-lower-quadrant US. Ultrasound findings analyzed appendix diameter, compressibility, increased vascularity, presence of appendicolith, inflammatory changes, right-lower-quadrant fluid near the appendix, lower abdominal fluid, tenderness during US, and lymph nodes. Diagnosis was confirmed via surgical pathology.

RESULTS

There were 1252 patients who enrolled, 60.8 (762) had their appendix visualized, and 39.1 (490) did not. In children where the appendix was seen, 35.2% (268) were diagnosed with appendicitis. Among patients with a visualized appendix, the likelihood of appendicitis was significantly greater if the appendix diameter was 7 mm or greater (odds ratio [OR], 12.4; 95% confidence interval [CI], 4.7-32.7), an appendicolith was present (OR, 3.9; 95% CI, 1.5-10.3), inflammatory changes were seen (OR, 10.2; 95% CI, 3.9-26.1), or the white blood cell (WBC) count was 10,000/μL (OR, 4.8; 95% CI, 2.4-9.7). A duration of abdominal pain of 3 days or more was significantly less likely to be associated with appendicitis (OR, 0.3; 95% CI, 0.08-0.99). The absence of inflammatory changes, WBC count of less than 10,000/μL, and appendix diameter of 7 mm or less had a negative predictive value of 100%.

CONCLUSIONS

When the appendix is seen on US but diagnosis of appendicitis is questioned, the absence of inflammatory changes, WBC count of less than 10,000/μL, and appendix diameter of 7 mm or less should decrease suspicion for appendicitis.

Point-of-Care Ultrasound for Undifferentiated Abdominal Pain in a Pediatric Patient: A Proposed Algorithm

Abdominal pain is a common presentation in the pediatric emergency department and may pose a diagnostic challenge to the physician. Although most abdominal pain is benign, the presence of abdominal pain may represent a surgical emergency. We present an atypical presentation of perforated appendicitis in a child with 2 weeks of abdominal pain, in whom point-of-care ultrasound expedited diagnosis and patient disposition. We then recommend a diagnostic approach for using point-of-care ultrasound in a pediatric patient with undifferentiated abdominal pain.

Nongynecologic Causes of Pelvic Pain: Ultrasound First

Ultrasonography (US) is often the first-line imaging study used to evaluate women who present with acute or chronic pelvic pain. Detection of nongynecologic causes of pelvic pain is critical, because delay in diagnosis can cause significant morbidity and mortality. Evaluation of these entities requires a variety of transducers to achieve optimal imaging depth and changes in patient positioning. Specific imaging techniques (such as graded compression) may be required if bowel pathology is suspected. Contrast-enhanced ultrasonography is increasingly used to improve detection of certain entities. The US appearance of common gastrointestinal and urinary tract-related causes of pelvic pain is reviewed.

Falling through the worm hole: an exploration of the imaging workup of the vermiform appendix in the pediatric population

Despite the thousands of articles discussing appendicitis in the literature, the dilemma of how to best diagnosis and manage pediatric appendicitis remains unsettled. Over the past decade, evidence has been mounting about the use of antibiotics as the sole therapy in uncomplicated appendicitis in the adult population. This debate has even recently bled over into the lay press. While this change in practice pattern is still in its infancy for the pediatric population, radiologists should be aware of this change in therapy and how it can impact the imaging work-up and relevant findings. This article concisely summarizes the imaging findings and various imaging pathways to arrive at the diagnose of appendicitis with an emphasis of how to best be of use to our surgical colleagues in this evolving paradigm. It also highlights venues for further research, namely increasing accuracy of differentiating complicated from uncomplicated appendicitis.

Diagnosis of appendicitis in the paediatric emergency department: an update

PURPOSE OF REVIEW

Concern regarding appendicitis is a common reason for presentation to the paediatric emergency department. We review recent progress in the use of biomarkers, imaging and clinical scoring systems in improving diagnostic accuracy in suspected appendicitis in children.

RECENT FINDINGS

Use of ultrasound, often performed at the bedside, is becoming more widespread with a parallel reduction in computed tomography (CT) use. Protocols for image acquisition and interpretation have been shown to improve diagnostic accuracy. Novel biomarkers have been explored and clinical diagnostic algorithms refined but none have achieved the level of diagnostic accuracy required.

SUMMARY

Appendicitis remains a clinical diagnosis. Point of care ultrasound is increasingly available and offers higher diagnostic accuracy than several routinely performed laboratory investigations. Recent publications provide support for increased use of clinician performed ultrasound, increased use of MRI, less use of CT, less emphasis on basic laboratory investigation and a renewed respect for the value of serial examination, particularly early in the course of illness.