Accuracy of ultrasonography in diagnosing acute appendicitis during pregnancy based on surgical findings

Using MRI appendicitis scale and DWI for the diagnosis of acute appendicitis in pregnant women

OBJECTIVES

To assess the performance of MRI scale for the diagnosis of acute appendicitis in pregnant women and to determine the added diagnostic value of diffusion-weighted imaging (DWI).

METHODS

From January 2018 to December 2020, 80 patients were included. All MRI were performed with a 1.5-Tesla scanner with anterior array body coil. This analysis included (1) T2-weighted imaging (T2WI), (2) fat-saturated T2WI, and (3) DWI. Two radiologists blinded to the diagnosis recorded their assessment of four findings: appendiceal diameter, appendiceal wall thickness, luminal mucus, and periappendiceal inflammation. The MRI scale of acute appendicitis which ranged from 0 to 4 was determined from these factors. An additional one point was added to the MRI appendicitis scale in those patients with evidence of appendiceal restricted diffusion on DWI. The diagnostic values and predictive factors were computed.

RESULTS

Multivariate analysis demonstrated that the calculated MRI appendicitis scale was a significant independent predictor of acute appendicitis with a sensitivity of 96.6%, specificity of 90.2%, and PPV of 84.8%. The odds ratio of appendicitis is increased by 22.3 times for every increase in one point on the MRI appendicitis scale. Therefore, the addition of one point for restricted diffusion in the appendix on DWI imaging can add substantial value, both positive and negative predictive value, towards making an accurate diagnosis of acute appendicitis.

CONCLUSIONS

MRI appendicitis scale is an objective and significant independent predictive factor for acute appendicitis in pregnant women. Incorporation of diffusion weighted imaging to MRI can improve diagnosis of acute appendicitis.

CLINICAL RELEVANCE STATEMENT

MRI appendicitis scale is an objective and significant independent predictor of acute appendicitis in pregnant women. Incorporation of DWI/ADC map to MRI examinations can improve diagnosis of acute appendicitis in pregnant women.

KEY POINTS

• MRI appendicitis scale is an objective and significant independent predictive factor for acute appendicitis in pregnant women. • The odds ratio of appendicitis can be increased by 22.3 times for every increase of one unit in MRI scale. • Incorporation of diffusion-weighted imaging to MRI examinations can add value to the scale (4.2 ± 0.7 vs. 0.7 ± 1.1; p < 0.001) among pregnant women with appendicitis versus pregnant women without appendicitis.

Adverse Fetal Outcomes and Maternal Mortality Following Nonobstetric Abdominopelvic Surgery in Pregnancy: A Systematic Review and Meta-analysis

OBJECTIVE

To quantify the absolute risks of adverse fetal outcomes and maternal mortality following nonobstetric abdominopelvic surgery in pregnancy.

SUMMARY BACKGROUND DATA

Surgery is often necessary in pregnancy, but absolute measures of risk required to guide perioperative management are lacking.

METHODS

We systematically searched MEDLINE, EMBASE, and EvidenceBased Medicine Reviews from January 1, 2000, to December 9, 2020, for observational studies and randomized trials of pregnant patients undergoing nonobstetric abdominopelvic surgery. We determined the pooled proportions of fetal loss, preterm birth, and maternal mortality using a generalized linear random/mixed effects model with a logit link.

RESULTS

We identified 114 observational studies (52 [46%] appendectomy, 34 [30%] adnexal, 8 [7%] cholecystectomy, 20 [17%] mixed types) reporting on 67,111 pregnant patients. Overall pooled proportions of fetal loss, preterm birth, and maternal mortality were 2.8% (95% CI 2.2-3.6), 9.7% (95% CI 8.3-11.4), and 0.04% (95% CI 0.02-0.09; 4/10,000), respectively. Rates of fetal loss and preterm birth were higher for pelvic inflammatory conditions (eg, appendectomy, adnexal torsion) than for abdominal or nonurgent conditions (eg, cholecystectomy, adnexal mass). Surgery in the second and third trimesters was associated with lower rates of fetal loss (0.1%) and higher rates of preterm birth (13.5%) than surgery in the first and second trimesters (fetal loss 2.9%, preterm birth 5.6%).

CONCLUSIONS

Absolute risks of adverse fetal outcomes after nonobstetric abdom- inopelvic surgery vary with gestational age, indication, and acuity. Pooled estimates derived here identify high-risk clinical scenarios, and can inform implementation of mitigation strategies and improve preoperative counselling.

Diagnostic accuracy of ultrasound in diagnosing acute appendicitis in pregnancy: a systematic review and meta-analysis

BACKGROUND

Lack of timely diagnosis of acute appendicitis (AA) can lead to perforation and peritonitis, which might be associated with complications such as miscarriage, preterm delivery, fetal loss, and even maternal mortality. The aim of the present systematic review and meta-analysis was to evaluate the accuracy of ultrasonography (US) for diagnosing AA in pregnant patients.

METHODS

We performed the present systematic review and meta-analysis based on Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Using a pre-designed standard datasheet, the two authors summarized the data of each study independently. Pregnant women with diagnosed or suspected AA, who have undergone ultrasonography, as well as using CT scan or surgery as the standard method, were included.

RESULTS

A total of 8 studies consisting of 1593 patients were included. The main analysis showed that the overall sensitivity and specificity were 77.6% and 75.3% for US in diagnosing AA in pregnancy. The sensitivity of US in the first, second, and third trimesters of pregnancy were 69%, 63%, and 51%, respectively. While the corresponding figures for specificity were 85%, 85%, and 65%. There was a significant difference in the diagnostic performance of US between the first two trimesters and the third one. The DORs in these three trimesters were 36, 26, and 1.92, respectively.

CONCLUSIONS

Ultrasound evaluation showed a low diagnostic accuracy for acute appendicitis in pregnant women, especially during the third trimester. These patients should be diagnosed early and accurately to prevent both complications and unnecessary operations. It can be recommended to consider alternative imaging, mostly after negative or uncertain US.

Body mass index as an indicator of the likelihood of ultrasound visualization of the appendix in pregnant women with suspicion of appendicitis

PURPOSE

To determine if clinical characteristics of pregnant women are associated with the likelihood of ultrasound (US) visualization of the appendix in cases where there is a clinical suspicion of appendicitis.

MATERIALS AND METHODS

A retrospective study of 471 pregnant patients with suspicion of appendicitis from 2009 to 2018 were studied. Patients underwent sonography of the appendix as their initial imaging study. The association of body mass index (BMI) and gestational age with sonographic visualization of the appendix was analyzed using logistic regression. Cut-off values were determined for BMI to predict visualization of the appendix.

RESULTS

The rate of visualization of the appendix on US was 16% (95% CI 12% to 19%). When stratified by trimester of pregnancy, rebound pain on compression US examination in the 1st trimester and BMI in the 2nd and 3rd trimesters were identified as predictors of US visualization. Applying BMI cut-off values rounded to the nearest whole number, 36, 30, and 26 in the 1st, 2nd, and 3rd trimesters, non-visualization rates would be reduced by 16% (95% CI 10% to 25%), 35% (95% CI 29% to 42%), and 67% (95% CI 58% to 74%). Using BMI index cut-off values would reduce the number of primary US examinations by 35% (95% CI 30% to 39%) and increase the rate of visualization by 6% (95% CI 0.02% to 12%, P = 0.04).

CONCLUSION

Using BMI cut-off values for determining the efficaciousness of US visualization of the appendix in pregnant women with suspicion of appendicitis could significantly reduce the non-visualization rate.

Ultrasound morphology of cecal appendix in pet rabbits

PURPOSE

Cecal appendix is the terminal part of cecum and is characteristic of rabbit, among domestic animals. The purpose of this work is to evaluate its morphology upon ultrasound.

METHODS

A prospective study was planned for the duration of approximately 1 year. Rabbits presented in the study period for abdominal ultrasound with no clinically evident alterations of the gastrointestinal tract were eligible for inclusion in the study. Abdominal ultrasound was performed under manual restrain with a high frequency linear probe (8-18 MHz).

RESULTS

Cecal appendix was visualized in 40/42 rabbits (95.2%) with median or left paramedian views. The wall appeared multilayered in accordance with normal bowel anatomy, and the luminal content showed in all cases an alimentary pattern. Measurement of appendix wall thickness (AWT) was possible in all 40 rabbits in which the appendix was visualized while measurement of the appendix diameter (AD) was possible in 39 rabbits. Reference intervals for AWT were 1.1-2.1 mm, and for AD were 3.9-8.8 mm. There was a negative correlation between age and AWT (r = - 0.35, P = 0.027) and a moderate positive correlation between AWT and AD (r = 0.71, P < 0.001).

CONCLUSIONS

Cecal appendix is recognizable via ultrasound in the vast majority of rabbits. We describe the normal morphological aspect of the appendix and we provide reference intervals for wall thickness and diameter of the appendix, in order to aid in the diagnosis of disorders of the appendix. The negative correlation between age and AWT indicates lower values of AWT associated with increasing age that could represent the physiological decrease in the immunitary function of the appendix in aged rabbits.

Acute Appendicitis during Pregnancy; Results of a Cohort Study in a Single Iranian Center

Objective

To determine the effects of pregnancy on the presentation, management, surgical and obstetrics outcome of patients with acute appendicitis.

Methods

This prospective cohort study was conducted during a 2-year period from 2014 to 2016 in Shahid Faghihi hospital of Shiraz University of Medical Sciences. We enrolled all the pregnant individuals with acute appendicitis who required surgical appendectomy. We also enrolled age-matched controls of non-pregnant women undergoing open appendectomy during the study period. The presentation, clinical and laboratory characteristics, surgical and obstetrics outcomes were determined in both study groups and were further compared between them. In order to determine the determinants of outcome, we also ran a multivariate logistic regression model.

Results

Overall we included a total number of 584 patients with presumed appendicitis among whom there were 58 (9.94%) and 526 (90.06%) non-pregnant individuals. The pregnant patients had significantly longer duration of symptoms (p=0.038), lower temperature (p=0.026), longer duration of hospital stay (p=0.026) and higher rate of hospital admission longer than 2 days (p=0.031). The complications of the surgical procedure were comparable between the two study groups except for the pneumonia which was significantly higher in pregnant patient (p=0.041). After adjusting for confounders such as age and ethnicity, pregnancy remained significantly associated with lower temperature (p=0.018), longer symptom duration (p=0.042) and higher rate of pneumonia (p=0.049).

Conclusion

Acute appendicitis during the pregnancy was associated with longer duration of symptoms, lower body temperature and higher rate of pneumonia. The pregnancy and neonatal outcomes were comparable to the previously reported data.