Spectral Doppler Waveforms for Diagnosis of Appendicitis: Potential Utility of Point Peak Systolic Velocity and Resistive Index Values

Diagnostic performance of spectral Doppler in acute appendicitis with an equivocal Alvarado score

PURPOSE

This study aims to evaluate the added value of duplex Doppler examination to the routinely graded compression grayscale ultrasound (US) for patients with suspected acute appendicitis (AA) in correlation with surgical management outcomes.

METHODS

The study lasted from January 2020 to March 2021. Throughout that period, patients who had suspected appendicitis were included with a visible appendix in the grayscale US. These patients were categorized clinically based on Alvarado's score. They underwent graded compression grayscale US of the appendix and duplex Doppler study. Subsequently, they were assigned for non-contrast multislice computed tomography (MSCT) according to Alvarado's score and underwent either emergency appendicectomy or conservative clinical management afterward. A Student's t-test was used to determine if there were significant differences in the mean values between the groups. The diagnostic performance of spectral Doppler US for the diagnosis of AA was depicted.

RESULTS

Eighty-four patients with visualized color flow in the appendicular Doppler US were enrolled, with 60 (71.4%) having AA, and 24 (28.6%) not having appendicitis. Spectral Doppler criterion of PSV greater than 8.6 cm/s demonstrated a high sensitivity of 91.67% and specificity of 77.78% for patients with Alvarado score ranging from 4 to 7, and appendiceal MOD ranging from 6 to 8 mm, while a discriminatory criterion of RI greater than 0.51 had a high sensitivity of 100% and a relatively lower specificity of 66.67%.

CONCLUSION

The patients with AA have significantly higher point PSV and point RI values than those without AA and are especially useful in equivocal patients whose MODs and Alvarado scores are in the diagnostically equivocal ranges of 6-8 mm and 4-7, respectively, with the point PSV and RI demonstrating negative predictive value 87.5% and 100%.

The utility of spectral Doppler evaluation of acute appendicitis

PURPOSE

The use of spectral Doppler, peak systolic velocity (PSV), and resistive index (RI) imaging criteria to improve the accuracy of acute appendicitis diagnosis is hypothesized.

METHODS

Graded compression ultrasound was performed for suspected patients. The spectral Doppler evaluation was conducted while observing the appendix. A total of 152 patients (82 males and 70 females, ages 4-63 years, mean age of 24.5 years) were examined using the spectral Doppler waveform between 2018 and 2019. RI and PSV values of patients with and without appendicitis were compared to histopathologic findings. SPSS 26 was used to analyze the data, including using descriptive statistics and measures of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

RESULTS

Appendicitis was confirmed in 95 patients (62.5%) and rejected in 57 patients (37.5%). For the diagnosis of appendicitis, the area under the curve (AUC) of receiver operating characteristic (ROC) for RI (0.92 with 95% confidence interval (CI): 0.88, 0.97; P = 0.001) and PSV (0.96, with 95% CI: 0.93, 1.00; P = 0.001) was calculated. The discriminatory RI ≥ 0.49 demonstrated high sensitivity (90.5%) and low specificity (86%), and the discriminatory PSV ≥ 9.6 cm/s had high specificity (94.7%) and sensitivity (94.7%) for appendicitis.

CONCLUSION

By incorporating spectral Doppler criteria into routine graded compression ultrasound, the diagnostic accuracy of acute appendicitis was increased. In comparison, high PSV and RI values of the appendix with a cut-off point of 9.6 cm/s and 0.49 differ significantly between positive and negative appendectomy patients.

Hyperechoic Periappendiceal Fat: Evaluation of Criteria for Improving Specificity in the Sonographic Diagnosis of Appendicitis in Pediatric Patients

OBJECTIVES

To test the hypothesis that abutting and encasing types of hyperechoic periappendiceal fat are specific sonographic indicators of appendicitis in pediatric patients, including individuals with maximum outer diameters (MODs) of 6 to 8 mm in whom diagnosis by the MOD alone is known to be equivocal.

METHODS

Appendiceal sonograms of 271 consecutive pediatric patients were retrospectively evaluated for hyperechoic periappendiceal fat (globular, ≥1.0 cm; categorized as type 0, none; type 1, "abutting," encompassing <180° of the appendiceal circumference; or type 2, "encasing," encompassing 180° or more of the appendiceal circumference) and the MOD. Histopathologic and medical records constituted reference standards. Statistical methods included the binomial distribution, logistic regression, a receiver operating characteristic analysis, and the exact McNemar test.

RESULTS

All patients with hyperechoic fat and 105 of 107 patients with appendicitis had MODs of 6 mm or greater. The MOD and fat types 1 and 2 each were significantly associated with appendicitis in the univariable regression. The MOD and fat type 1 were independently associated with appendicitis in multivariable regression (odds ratio, 24.97; P = .034; and odds ratio, 5.35; P < .001, respectively). Specificities of an MOD of 6 to 8 mm and an MOD of 6 mm or greater alone were 89.0% (95% confidence interval, 83.2%-93.4%); these increased to 100.0% each (95% confidence interval, 97.8%-100.0%; P < .001) when combined with fat types 1, 2, and either 1 or 2 as diagnostic criteria, with positive predictive values of 100.0%.

CONCLUSIONS

Types 1 and 2 periappendiceal fat are specific indicators of appendicitis, and both improve specificity compared to the MOD. Importantly, they add specificity in diagnosing appendicitis in patients with diagnostically equivocal MODs of 6 to 8 mm.

The Borderline-Size Appendix: Grayscale, Color Doppler, and Spectral Doppler Findings That Improve Specificity for the Sonographic Diagnosis of Acute Appendicitis

Diagnostic criteria for acute appendicitis using graded compression sonography have been well established based on the maximum outer diameter (MOD) of the appendix, with MOD values of <6 mm nearly always indicating normal appendices and MOD values of >8 mm nearly always indicating appendicitis. However, the "borderline-size" appendix, meaning one whose MOD lies between these ranges (ie, an appendix with MOD of 6-8 mm), presents a diagnostic dilemma because appendices in this size range are neither clearly normal nor abnormal when diagnosis is based on the MOD alone; accordingly, such borderline MOD values are diagnostically equivocal, and sonographic diagnosis must rely on sonographic findings other than the MOD. The goal of this review was to examine the additional sonographic findings that can add specificity and help enable an accurate diagnosis to be made in patients with borderline-size appendices.

Suspicion of acute appendicitis in adults. The value of ultrasound in our hospital

OBJECTIVE

To evaluate the accuracy of ultrasonography for the diagnosis of acute appendicitis in adults, to calculate the negative appendicectomy rate in operated patients and the accuracy of pre-defined diagnostic categories and to identify statistically significant signs and symptoms of acute appendicitis in ultrasonography.

MATERIAL AND METHODS

Descriptive prospective study in which we collected the findings of the urgent ultrasonographies ordered in a one-year period for adult patients with pain in the right iliac fossa (RIF), along with their symptoms. We classified them in 5 different diagnostic categories presented in the radiological report: normal appendix, non-visible appendix and no secondary signs, non-conclusive, probable appendicitis, certain appendicitis. By mean of the Stata14 software descriptive analysis, T-test and Chi-square were performed and the data were compared with the final pathological report.

RESULTS

Population: 139 patients (45% men, 55% women), mean age: 32,68 (15-84). Prevalence of acute appendicitis: 50,35% (70/139). Negative appendicectomy rate: 0%. Negative predictive value for the categories 1,2 and 3 taken together: 90,78%. Positive predictive value for the categories 4 and 5 taken together: 100%. Ultrasound sensibility and specificity 90% and 100%, respectively. Statistically significant signs and symptoms (p<0.05): RIF pain, fever, leukocytosis, left shift, visible appendix, non-compressibility, hyperechogenic fat, appendicolith and free fluid.

CONCLUSION

Ultrasound is very accurate for the diagnosis of acute appendicitis in adults.