Enhancing pediatric abdominal pain diagnosis: the role of ultrasound layered scanning technique

Introduction

Abdominal pain in children is a common symptom with numerous potential causes, making it a significant clinical feature in a variety of medical conditions. It can indicate acute abdominal conditions, such as appendicitis, as well as gastrointestinal, respiratory, nervous system, and urinary disorders (1). Diagnosing, differentiating, and treating pediatric abdominal pain pose challenges, as young children often cannot clearly articulate their symptoms. This makes abdominal pain in children particularly difficult to assess, and crying often becomes the primary communication method for discomfort (1). Therefore, accurate diagnostic tools are essential for confirming the underlying cause and guiding treatment.

Ultrasound has been widely used in pediatric care since the 1970s, offering a safe, non-invasive, and effective method for diagnosing acute abdominal conditions. It allows for precise diagnoses based on characteristic ultrasound findings, and plays a crucial role in the differential diagnosis of pediatric abdominal pain (2). Compared to imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI), ultrasound is radiation-free and more accessible. However, with the increasing prevalence of obesity in children due to improved living standards, ultrasound imaging can be challenging. Higher body fat percentages in children may result in unclear images or limited examination accuracy (3). There is, therefore, a need for advanced ultrasound technologies that can improve diagnostic precision, especially for identifying the causes of abdominal pain in overweight or obese children.

To address these challenges, we draw upon Zhao’s three-layer examination approach for pediatric abdominal pain, which employs layered ultrasound scanning to better identify underlying causes (4). This method divides the abdominal cavity into three distinct layers—pre-peritoneal, intra-abdominal, and retroperitoneal—allowing for more targeted scanning and the identification of abnormal echoes. The goal of this study was to explore new ultrasound approaches and methods that can improve the identification of abdominal pain causes in pediatric patients, particularly in those who are overweight or obese.

Pediatric abdominal pain can generally be classified into two categories: specific abdominal pain and nonspecific abdominal pain (5,6). Specific abdominal pain is associated with well-defined etiologies and is typically easier to diagnose. Ultrasound imaging can often differentiate the causes of specific abdominal pain, such as gallstones, ureteral stones, imperforate hymen, or gynecological ovarian lesions (7,8). However, nonspecific abdominal pain may have multiple, less defined causes, requiring careful evaluation to determine the underlying issue.

Despite the challenges presented by obesity in pediatric ultrasound imaging, there remains a strong need for precise diagnostic methods to improve the detection of abdominal pain causes in this population. The current study aimed to contribute to this need by investigating layered ultrasound as a promising approach to enhance diagnostic accuracy in pediatric abdominal pain. We present this article in accordance with the STROBE reporting checklist (available at https://qims.amegroups.com/article/view/10.21037/qims-24-1855/rc).

Methods

Patient data

We conducted a retrospective analysis of 507 cases involving pediatric abdominal pain. These cases were diagnosed either through clinical pathology or symptomatic treatment at our hospital between July 2016 and November 2017. The cohort consisted of 319 males and 188 females, ranging in age from 5 to 14 years, with an average age of 11±1.78 years. The specific cases for clinical diagnosis are shown in Table 1. The inclusion criteria stipulated that all cases had to be diagnosed within our department and consulted with the pediatric department, with ultrasound records documenting the identified lesions. Additionally, cases must have pathological results or been effectively treated conservatively by the Department of Pediatric Internal Medicine. We excluded 13 cases that involving pathology-confirmed abdominal pain conditions that were not documented by ultrasound. All cases were classified based on abdominal fat layer thickness into normal weight children, overweight children, and obese children.

The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). The study was approved by the Ethics Committee of Hangzhou Ninth People’s Hospital (No. YL-2024-056) and informed consent was obtained from all patients’ guardians.

Instruments and methods

The GE LOGIQ E9 (Chicago, IL, USA) and Toshiba Aplio 810 (Tokyo, Japan) ultrasound diagnostic systems were utilized, equipped with a 3–6 MHz abdominal probe and a 7–12 MHz high-frequency probe.

Patients exhibiting abdominal pain were immediately referred to our department by clinical doctors. The ultrasound physicians employed a double-blind method, assigning patients to two primary ultrasound physicians who used different examination methods. After completing a conventional site-specific examination, layered scanning technology was applied. Two physicians independently recorded the results of the two types of examinations, and images were transferred to computers via DICOM.

Clinicians promptly referred patients with abdominal pain to our department. The ultrasound specialists used a double-blind method, directing them to two different attending ultrasound physicians who applied different examination techniques. One physician performed a routine scan, and once completed, the patient was transferred to the second physician for stratified screening. The results of both examinations were recorded, and the images were transmitted to the computer via DICOM. The stratified screening technique involved using high-resolution (high-frequency probe) scanning after the internal organs were examined. The first layer of examination focused on detecting any peritoneal thickening in the lower abdominal wall. The second layer checked for thickening or aggregation of the greater omentum, mesentery, and then the appendix, intestines, and inguinal region. The third layer examined the peritoneum and pelvic area for any masses. During the ultrasound examination, the thickness of the children’s abdominal fat layer was also observed, and any correlation between the examination methods and abdominal fat thickness was recorded.

Layered scanning technology involves scanning with high resolution (using a high-frequency probe) after the internal organs are inspected. The first layer examined the lower abdominal wall for any peritoneal thickening lesions. The second layer assessed the convergence and thickening of the omentum and mesentery followed by observation of the appendix and intestinal tract, including the inguinal area. The third-layer examination checked for any tumors in the retroperitoneum and pelvic region.

Statistical analysis

The general data were analyzed using mean ± standard deviation. The t value and P value for the data between the two groups were calculated using SPSS 19 statistical software. The detection rates for different abdominal wall thicknesses were compared using the chi-square test to calculate the P value.

Results

The comparison between the conventional group and the layered scanning group revealed several significant differences in detection rates (Table 2). For mesenteric lymphadenopathy, the detection rate was 86% (184/214) in the conventional group and 100% (214/214) in the layered scanning group. In terms of peritonitis, the detection rate was significantly higher in the layered scanning group, with 94% (45/48) compared to 27% (13/48) in the conventional group. The enhanced detection in the layered scanning group was attributed to improved identification of peritoneal thickening, which facilitated the detection of related conditions, such as mesenteric fat inflammation, appendicitis, and urachal inflammation. For mesenteric fat inflammation, the detection rates were 46% (6/13) and 100% (13/13), respectively; for appendicitis, 63% (30/48) and 94% (45/48); and for urachal inflammation, 0% (0/2) and 100% (2/2) in the conventional and layered scanning groups, respectively.

Regarding the detection of substantial lesions, such as gallstones, ureteral stones, intestinal intussusception, hymen atresia, ovarian luteal rupture, and ovarian torsion, both groups demonstrated a 100% detection rate. For gastrointestinal lesions, such as gastroenteritis, inguinal hernia, and intestinal ascariasis, the layered scanning group showed superior performance. The detection rates for gastroenteritis were 32% (12/37) in the conventional group and 97% (36/37) in the layered scanning group, while inguinal hernia detection was 100% (36/37) in the conventional group and 100% (36/37) in the layered scanning group, with intestinal ascariasis detected at 100% (1/1) in both groups. There was minimal difference between the groups in detecting significant bowel distension associated with allergic purpura or monocytosis, with detection rates of 75% (9/12) and 92% (11/12) for allergic purpura, and 100% (1/1) for monocytosis in both groups. Additionally, the relationship between abdominal fat layer thickness and disease detection was examined. When the abdominal fat layer was less than 0.8 cm, there was no significant difference in disease detection rates between the two groups. However, when the abdominal fat layer thickness ranged between 0.8 and 1.7 cm, differences in detection rates were observed, with the most significant differences emerging when the abdominal fat layer thickness exceeded 1.7 cm.

Discussion

In cases of nonspecific abdominal pain, such as mesenteric lymph nodes, panniculitis, intestinal swelling, and thickening, or gastroenteritis, the absence of clear diagnostic markers and atypical imaging patterns present significant challenges for clinicians. Conventional scans often focus primarily on clinical targeted areas, which can lead to missed diagnoses if the underlying pathology falls outside of these regions. The majority of pediatric abdominal pain cases stem from intra-abdominal diseases, with gastric and duodenal conditions being the most prevalent. However, due to the limitations of ultrasound examination of the gastrointestinal tract, a diagnosis of acute gastroenteritis can only be confirmed after ruling out a range of other potential diseases (9,10). In contrast, the ultrasound layered scanning technique provides a significant advantage, improving detection rates by 98% compared to 82% in traditional methods (11). This method enhances the identification of pathologies that are typically overlooked in conventional scans, particularly in obese children, where traditional ultrasound images may be unclear or misinterpreted. In a study by Ma et al., for instance, obese children with abdominal pain were misdiagnosed with pancreatitis due to the inability of conventional ultrasound to provide clear imaging (12). However, the use of ultrasound stratified screening improved the accuracy of diagnosis, with detection rates of 96% compared to 73% in routine screening.

Layered ultrasound scanning offers several key advantages over traditional scanning. One of the primary benefits is its ability to enhance spatial resolution and provide more detailed images of abdominal organs. This method divides the abdominal structures into different layers, enabling a more comprehensive view of the abdominal cavity. It improves the identification of pathologies such as peritoneal thickening, appendicitis, or mesenteric panniculitis by examining not only the superficial but also the deeper layers of the abdomen. This multi-layered approach allows for better localization and characterization of lesions, which is particularly useful in cases of abdominal pain where multiple conditions may overlap or where deeper lesions are present. However, the technique’s success heavily depends on the experience and skill of the operator. While experienced practitioners can accurately use the layered scanning technique to detect subtle lesions, less experienced practitioners may miss small pathologies or misinterpret imaging results. Therefore, the reliability of the results is significantly influenced by the expertise of the ultrasound operator.

Despite these challenges, the layered ultrasound scanning technique is highly beneficial in diagnosing pediatric abdominal pain, especially in patients with obesity, where conventional ultrasound often struggles. For example, this method can help detect conditions like mesenteric lymphadenitis and appendicitis, which might otherwise be missed. The technique also aids in identifying peritoneal thickening, a critical indicator of inflammation or infection, prompting further investigation into the underlying cause. The ability to accurately assess the location, size, and boundaries of lesions, as well as their proximity to surrounding structures such as blood vessels, greatly enhances diagnostic precision. In this study, common conditions included suppurative appendicitis (Figure 1), panniculitis (Figures 2,3), and uracholitis (Figure 4).

Figure 1 The patient presented with acute migrating lower right abdominal pain. Ultrasound examination revealed a normal appendix with an echo, measuring 0.4 cm in diameter and showing no wall thickening. Utilizing a three-layer technique, an abnormal lesion was detected in the second layer. The surrounding intestinal wall exhibited hypoechoic thickening with bright spots in the center. Diagnosis: cecal diverticulum with fecolith entrapment. Postoperative diagnosis: cecal diverticulum. A slight thickening of the peritoneum was marked in the figure.

Figure 2 The patient presented with acute left abdominal pain lasting for half a day. A history of trauma was noted during investigation. Conventional ultrasound did not reveal remarkable findings. However, subsequent use of a high-frequency probe near the anterior abdominal cavity revealed a plaque-like area with high echogenicity, distinct tenderness and unclear boundaries. No other abnormalities were observed. The provisional ultrasound provisional diagnosis was panniculitis. The patient received anti-inflammatory and analgesic therapy and showed normal findings during a follow-up visit after one week. Abnormality was marked by the white arrow.

Figure 3 A child with panniculitis presented with left lower abdominal pain lasting for one day, accompanied by noticeable tenderness in the left lower abdomen. Ultrasound examination revealed a plaque-like high echo with unclear boundaries between the skin and the peritoneum (A). The patient’s condition improved following symptomatic anti-inflammatory treatment and localized physical therapy (B). The measurements were taken at the lipid membrane thickening.

Figure 4 The child presented with lower abdominal distension and positive abdominal tenderness. Ultrasound examination of the superficial umbilical urachus revealed cystic enlargement characterized by hypoechoic features (white arrow) and minimal blood flow signals. Diagnosis: uracholitis.

However, there are some limitations to the layered scanning technique. The most significant drawback is its reliance on the operator’s skill. The technique requires extensive training to ensure accurate image interpretation and effective use of the multi-layered approach. Inexperienced examiners may fail to recognize subtle differences in tissue characteristics or overlook critical findings, leading to misdiagnoses or missed conditions. In this study, during the investigation of vomiting, clinical suspicions related to intussusception resulted in overlooked diagnoses of pyloric hypertrophy due to the failure to detect cervical-like changes in the pyloric canal (Figure 5). Moreover, the increased complexity of layered scanning may make it more time-consuming than conventional methods, potentially leading to longer examination times and delays in diagnosis.

Figure 5 The patient experienced frequent vomiting for one month and underwent a medical examination. Notably, a significant thickening of the muscular layer at the pylorus was observed, resembling a cervical-like change. Diagnosis: pyloric hypertrophy. The diagnosis was missed here because the stomach is not examined by conventional ultrasound.

In comparison to traditional ultrasound, which may focus on specific areas with limited scope, the layered scanning method provides a more thorough examination, ensuring that no part of the abdomen is overlooked. This is particularly important in pediatric patients, where nonspecific abdominal pain is often attributed to conditions like gastroenteritis, mesenteric panniculitis, or intussusception (13). These conditions, which are typically located in the middle layer of the abdomen, can be missed if only a focused scan is performed. Additionally, layered scanning is especially valuable when examining the gastrointestinal tract and its surrounding structures (14). The ability to identify abnormal masses (such as lymphoma or abdominal tumors), alterations in gastrointestinal wall echogenicity, and gas accumulation allows for more accurate diagnosis of conditions like intussusception or appendicitis (15). Furthermore, the layered scanning method provides significant improvements in the detection of abnormalities that might be difficult to assess with conventional ultrasound, such as peritoneal thickening, mesenteric panniculitis, and even more subtle conditions like diverticulitis. For example, when a high-frequency probe passes over the spleen and detects low-echogenicity granular nodules within it, a splenic lesion is strongly suspected (Figure 6). The high-resolution probes used in the technique are also particularly effective for assessing hollow organs like the gastrointestinal tract and the urinary system, ensuring that any abnormalities, including stones, cysts, and organ lesions, are identified with greater clarity.

Figure 6 Clinically diagnosed with infectious mononucleosis, the abdominal scan initially revealed no obvious abnormalities. However, a subsequent examination using a high-frequency probe detected increased splenic echogenicity with multiple hypoechoic areas. Notably, solid organs such as the liver and spleen exhibited lymphocyte infiltration, emphasizing the need for early anti-inflammatory treatment.

The application of layered ultrasound scanning not only improves diagnostic accuracy but also enhances the overall quality and efficiency of pediatric abdominal pain management. By providing a more comprehensive examination of the abdominal cavity, this technique ensures that clinicians can make more informed decisions and reduce the likelihood of misdiagnosis or delayed diagnosis. This approach is particularly important in pediatric populations, where early and accurate diagnosis is crucial for preventing complications and ensuring appropriate treatment.

Conclusions

In conclusion, the layered ultrasound scanning technique significantly improves disease detection in pediatric patients with abdominal pain, particularly in cases where conventional ultrasound may miss key findings. This method enhances the visualization of abdominal and pelvic masses, solid organ lesions, and bowel wall thickening by providing a more comprehensive, multi-layered view. While obesity can complicate traditional ultrasound scans by increasing fat tissue and altering organ positioning, the stratified screening technique effectively reduces interference from surrounding tissues, making it easier to detect abnormalities. Given its proven effectiveness in improving diagnostic accuracy, especially in complex cases, stratified screening is a valuable approach with broad potential for clinical application in pediatric patients.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://qims.amegroups.com/article/view/10.21037/qims-24-1855/rc

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-24-1855/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). The study was approved by the Ethics Committee of Hangzhou Ninth People’s Hospital (No. YL-2024-056) and informed consent was obtained from all patients’ guardians.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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