Evaluating the efficacy of sequential cross-sectional scanning and combined teaching methods for prenatal screening of fetal conotruncal anomalies | BMC Medical Education

Sonographers must possess both a strong foundation in theory and proficient operational skills to achieve accurate diagnoses. Unlike other imaging techniques, ultrasound examinations are real-time and dynamic. The quality and clarity of the resulting images directly depend on the operator’s technical expertise, ultimately determining the effectiveness and specificity of the ultrasound diagnosis. Fetal cardiac ultrasound, however, presents a significant challenge due to its susceptibility to various factors, including fetal position, gestational age, and image quality. As the largest fetal cardiac ultrasound diagnosis center in the region, our teaching experience for many years has made us find that the effect of simple theoretical teaching is very small. Many students still cannot complete the fetal heart scan well after half a year of advanced study, and the rate of missed diagnosis and misdiagnosis is high [15]. This is particularly true for the diagnosis of fetal conotruncal anomalies, a highly complex condition. The diverse presentation and intricate spatial arrangement of blood vessels in such cases contribute to a significant “knowledge gap” among ultrasound practitioners regarding diagnosis [16]. To address this critical need, we developed a comprehensive training program specifically designed to improve the ability of sonographers in our region to diagnose and differentiate fetal CA.

According to the screening guidelines of ISUOG, the Chinese expert group has formulated the consensus on the medical mode and technical process of multidisciplinary diagnosis and treatment of fetal heart disease in maternal-fetal medicine and precise integration of prevention and treatment. Combined with the teaching experience of our center, we developed and implemented the reform of this teaching plan [17]. In China, where sonographers manage high patient volumes daily, optimizing prenatal ultrasound speed and accuracy remains a critical challenge. To address this, we propose cross-sectional sequential scanning. This method allows rapid, dynamic, and continuous observation of the heart and major blood vessels’ connection, shape, and diameter, facilitating accurate fetal heart disease diagnosis. Prior research has demonstrated that this approach significantly reduces examination time, offering valuable advantages for busy screening programs [5]. Our scanning method shares a similar principle with CT, MRI, and STIC-all structures [18, 19], particularly blood vessel spatial displacements, can be visualized dynamically within a continuous scan. This dynamic view offers valuable insights and reduces the impact of fetal position on scan quality [20,21,22]. These unique advantages make SCS particularly well-suited for diagnosing conotruncal anomalies.

Based on our experience, traditional teaching methods, particularly the prevalent LBL model, exhibit limited performance in evaluating students’ clinical skills and teaching quality. This teacher-centered approach hinders mutual communication and fails to cultivate students’ independent learning abilities, resulting in a less-than-optimal learning experience. This realization fueled our exploration of alternative methods, ultimately leading to the development of a novel training program that combines fetal heart SCS with a variety of teaching methods for screening fetal conotruncal anomalies.

Traditional teaching methods focus on rote memorization of textbook knowledge. This “picture-text-image” approach is less efficient compared to a direct “image-image” method. Moreover, individual student understanding and imagination can lead to misdiagnosis during this transformation process [23, 24]. To address this, we implemented a method that utilizes painting to solidify the mental images students form. Additionally, a mapping method is employed, using normal anatomical maps and serial scan images of common truncus malformations as references to expand and solidify anatomical knowledge [25]. This approach resulted in the experimental group achieving significantly higher scores in classroom tests compared to the control group, demonstrating their improved ability to read and grasp key points from videos. The painting process encourages students to review anatomical knowledge from various perspectives, promoting comprehensive analysis, memorization, and image refinement [26]. Mind mapping serves as a central pillar throughout the teaching process [24, 27]. For students in the experimental group, studying mind maps facilitates the connection between pathological and image changes, enhancing understanding and retention [28,30,30].

The combined application of these three teaching methods effectively cultivates students’ clinical practice and thinking skills [30]. Notably, pre-training participants’ theory and skill scores were generally low. This can be explained by several factors: none of the participants had prior experience with tertiary prenatal screening, they had not undergone systematic training on fetal heart screening, and their knowledge of scanning methods was limited. Additionally, the inherent complexity of conotruncal anomalies theory further hindered their grasp of both theoretical concepts and practical application. Encouragingly, the results of our training program demonstrate significant improvement. Students in group B achieved demonstrably higher scores in both theory and skill evaluations compared to group A. This highlights the importance of improved teaching methods and optimized scanning techniques in facilitating the acquisition of theoretical knowledge and practical skills. Overall, the training program led to a substantial enhancement in students’ understanding and diagnostic abilities regarding arterial conus malformations. We further provided the differences between two groups in the breakdown of the types of conotruncal abnormalities assessed, and found that except for the cases of APW and AVSD, the accuracy of group B was significantly higher than that of group A in other types, which further showed the effectiveness of MTM-SCS method. It is speculated that the diagnosis of APW and AVSD is relatively simple, so there is no difference between the two manifestations. Notably, while the trainees’ work experience varied, all participants were novices in fetal heart ultrasound screening. Post-training analysis revealed no significant correlation between trainee performance and their working years. This suggests that the training effect was equally beneficial for physicians with different levels of experience.

Survey results overwhelmingly demonstrated that students in the experimental group believed the combination of multiple teaching methods fosters their learning initiative and ability to explore, think, discover, and solve problems. This suggests that the method effectively engages students and encourages active participation. The rationale behind this approach is twofold. Firstly, each teaching method offers unique strengths and weaknesses. Combining these methods allows them to complement one another, a concept gaining traction in current research [31,29,32,33,34]. Secondly, the streamlined nature of ultrasound scanning techniques necessitates a deeper understanding and mastery of theoretical knowledge on the part of the students. This emphasis on theoretical foundations is reflected in our post-class theory and skills assessments. However, the survey results for question 1, which focused on perceived improvement in learning interest, did not reveal a significant difference between group B and group A. This might be attributed to the fact that participants in both groups were novices actively engaged in the training for the first time. Their high initial learning interest and strong motivation may have masked any potential difference between the groups.

This study offers several key advantages. First, all evaluation results were quantified and subjected to rigorous statistical analysis, providing a direct and objective measure of the training’s effectiveness. Second, we employed consistent content, forms, assessment criteria, and examiners for both pre- and post-training tests, minimizing potential sources of bias. Finally, the incorporation of slides, videos, hands-on activities, mind maps, and anatomical diagrams fosters an innovative and engaging learning environment, enhancing the overall acceptability of the training program.

This study also has its limitations. For example, the training program itself was relatively short, and it was not easy for us to assess long-term retention of skills among participants. While the training results are encouraging, follow-up studies are warranted, and future studies should consider longitudinal segmented teaching follow-up to assess whether the observed improvements persist over time. Therefore, we recommend that all trained sonographers complete the relevant national qualification examination and practice in time to maintain the effect of this training in the long term. Although this training was a single-center training, the training staff were sonographers from different hospitals. Previous studies in another center had confirmed that SCS scanning method had high application value in the diagnosis of vascular rings [4]. At present, network simulation, 3D printing and other technologies have been very mature. Technology has brought resources and convenience to study, so we should be good at finding problems and solving them in different ways. In future research, we will incorporate objective outcome measures, such as actual clinical diagnoses achieved by trained practitioners, as well as integrate digital tools, such as virtual reality simulation, to further enrich the learning experience, refine and extend this training program, and expand the scope of the study to include a larger and more diverse population of trainees to strengthen its external validity. Methods to further improve its effectiveness are sought to achieve the goal of universal improvement of prenatal screening skills in multi-center.