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.

Routine sonographic measurement of the near-field lateral ventricle during second-trimester morphologic scans.

OBJECTIVES: The purpose of this study was to determine whether measurement of the near-field lateral ventricular diameter can be reliably obtained within a practical time frame during second-trimester obstetric scans by angling the fetal head approximately 30° away from the horizontal image axis such that the posterior aspect of the fetal head lies closer to the transducer. METHODS: Fifty consecutive singleton pregnancies presenting for a routine-second trimester scan were recruited for this study. The far-field lateral ventricular diameter was measured, followed by the near-field lateral ventricular diameter using the proposed technique. The measurements were repeated by a second operator who was blinded to the first measurement. Both operators recorded the measurements taken and scored the level of visibility of the near-field lateral ventricle. The difference between the two operators' measurements was compared by a κ analysis. RESULTS: The near-field lateral ventricle was visualized in 49 of 50 cases (98%). There was no statistically significant difference in the measurement of the near-field lateral ventricular diameter by the two operators (P = .34). There was, however, a statistically significant difference in the time it took each operator to obtain the near-field measurement after the far-field measurement (P = .01). CONCLUSIONS: Manipulating the transducer to position the falx of the fetal head approximately 30° away from the horizontal image axis allows the near-field lateral ventricle to be routinely visualized and measured with a high degree of interoperator agreement and within a practical time frame once the operator is experienced in performing the technique.

Stratifying features for diagnosing hypertrophic stenosis on ultrasound: a diagnostic accuracy study.

BACKGROUND: Our aims were to determine if the diagnostic threshold for diagnosing hypertrophic pyloric stenosis (HPS) on ultrasound scan (USS) should be adjusted based on birth weight (BW), current weight (CW), gestational age (GA), chronological age (CA) or corrected gestational age (CGA). METHODS: All patients who underwent either an USS and pyloromyotomy (Group 1) or an USS for possible HPS (Group 2) at our tertiary centre between July 2013 and June 2019 were identified. Ideal threshold values are identified by measuring Youden's Index (J = sensitivity + specificity - 1; higher is better). Mean maximum Youden's Index for stratified results was compared to that for combined results. RESULTS: Two hundred and eighty-four patients were included (142 patients in both Group 1 and Group 2). Combined maximum Youden's Index for all patients was 0.92 for pyloric canal thickness (PMT) and 0.87 for pyloric canal length (PCL). Mean maximum Youden's Index was higher when patients were stratified by GA, CGA, BW or CW, and equivalent for CA. For pyloric canal length (PCL), mean maximum Youden's Index was lower for all variables when stratified compared to combined. There was no visual trend observed in the diagnostic thresholds between groups. CONCLUSION: Stratifying USS PMT diagnostic thresholds values based on age and weight is statistically more accurate than a single threshold in diagnosing HPS. However, the lack of visual correlation indicates a larger dataset is required to validate these results.

Evaluating the validity of ultrasound in diagnosing hypertrophic pyloric stenosis: a cross-sectional diagnostic accuracy study.

BACKGROUND: Our aims were to evaluate the ultrasound scan (USS) criteria in diagnosing hypertrophic pyloric stenosis (HPS), determine the best diagnostic threshold values for pyloric muscle thickness (PMT) and pyloric canal length (PCL), and assess the accuracy of flow through the pylorus. METHODS: All patients who underwent pyloromyotomy at our tertiary paediatric surgery centre between July 2013 and June 2019 were identified (Group 1). All patients undergoing an USS to investigate for a possible HPS and did not undergo pyloromyotomy were also identified (Group 2). Accuracy was determined by Youden's Index (J) with the highest J determining the ideal cut-off value. RESULTS: Two hundred and eighty-four patients (142 patients in each group) were included in the analysis. Using only the last USS before surgery, PMT provided an area under the curve (AUC) of 0.987 (n = 275), and PCL an AUC of 0.977 (n = 267). Ideal threshold values were 3.0 mm for PMT (J = 0.92), and 14.5 mm for PCL (J = 0.87). Combining PMT ≥3.0 mm with a PCL ≥14.5 mm resulted in a sensitivity of 95% and specificity of 99% (J = 0.94). The absence of flow through the pylorus on dynamic USS provided a sensitivity of 99% and specificity of 91% (J = 0.91; n = 277). CONCLUSION: Combining threshold values of 3.0 mm for PMT and 14.5 mm PCL provides the highest accuracy for diagnosing pyloric stenosis on an ultrasound scan. These combined values were more accurate than observing for the absence of flow through the pylorus.