Ultrasonography is a non-invasive imaging method without radiation exposure, allowing for safe repeated examinations [1]. Ultrasonography not only assists in the evaluation and management of patients but also provides real-time imaging to facilitate invasive procedures [1,2]. With advancements in technology, ultrasound devices have become smaller in size, making them suitable for bedside, and their cost has also decreased [3]. Owing to these advantages, the utilization of ultrasonography in clinical practice is steadily increasing [1].

In South Korea, as of 2022, ultrasound machines were distributed at an average rate of 82.3 per hospital in tertiary centers and 17.9 per general hospital, with a continuing upward trend. Ultrasound machines are relatively widely distributed in South Korea, with a total count of 40,208, compared with other imaging devices such as computed tomography (2,295) or magnetic resonance imaging (1,934) [4].

Ultrasound education aimed at undergraduate medical students not only increases interest in ultrasound and enhances ultrasound skills but also elevates the understanding of anatomy, physical examination, physiology, and pathology [5-8]. Therefore, the importance of ultrasound education for undergraduate medical students has been increasingly emphasized [9].

Ultrasonography can also play a significant role in the education of undergraduate medical students in neurology [10]. In the field of neurology, ultrasonography is used in various areas, including carotid, transcranial, neuromuscular, and neurocritical care [11-13]. Ultrasonography can contribute to the understanding of anatomy, such as the cervical arteries, optic nerve, and peripheral nerves, and can assist in comprehending neurovascular physiology through the assessment of blood flow direction and velocity using Doppler ultrasound. It also has the potential to aid in understanding the principles underlying neurological examinations, such as carotid artery auscultation and deep tendon reflexes, and contribute to understanding the pathology of various neurological disorders. Ultrasound can be used for procedures, such as central venous catheter insertion, which are necessary for patients in neurocritical care [2]. Utilizing ultrasound, which is frequently used in clinical practice, can enhance students’ understanding of clinical situations [14,15].

In South Korea, there are 38 medical colleges and two medical schools, with annual enrollment ranging from 40 to 140 students per institution. On average, approximately 3,000 students graduate annually. Generally, undergraduate medical students in premedical courses study basic science, medical science, general education, and liberal arts. During the 4 years of undergraduate courses at medical colleges and schools, first-year students focus on basic medical science, second-year students study clinical science, third- and fourth-year students engage in clerkship and optional courses.

Although the importance of ultrasound education in undergraduate medical education has been emphasized globally, it seems that it is not widely used for undergraduate medical students in South Korea [7]. Furthermore, the allocated instructional time is insufficient in institutions where ultrasound education is offered [16]. In this study, as part of the process of developing a neurosonology curriculum for undergraduate medical students in South Korea, we aimed to assess the current state of ultrasound education during pre-clerkship neurology courses and neurology clerkships in medical colleges and schools. Furthermore, we assessed the willingness to implement ultrasound education in the neurology curriculum at institutions that do not currently provide neurosonology education.

This study is a cross-sectional online survey conducted among neurology faculty at 38 medical colleges and two medical schools in South Korea. We distributed the survey questionnaire through Google Forms (Google, Mountain View, CA, USA) via e-mail from September 1, 2022, to October 31, 2022 (Table 1). Participation in the survey was voluntary and no incentives were provided. The survey consisted of 15 questions and took approximately 5 minutes to complete. The survey content was divided into three main sections: the current state of ultrasound lectures in neurology courses during the pre-clerkship phase of the curriculum, the current state of ultrasound education during neurology clerkships, and the intention to incorporate ultrasound education during neurology clerkships in the future. Detailed survey questions are presented in Table 1. In addition, we received information from the Korea Association of Medical Colleges regarding the number of medical students’ quota, the number of neurology faculties, years after the establishment and the location of the participating medical colleges and schools [17]. We analyzed the descriptive data, including frequency and percentage, using Microsoft Excel (Microsoft, Redmond, WA, USA). To compare the characteristics of medical colleges and schools that provide neurosonology education with those that do not, we used Fisher’s exact test or the Mann-Whitney U test. Two-tailed P-values of less than 0.05 were considered statistically significant. All analyses were performed using SPSS version 21.0 (IBM, Armonk, NY, USA). This study was approved by the Institutional Review Committee of Jeju National University Hospital (JEJUNUH 2023-11-004).

Responses were obtained from 32 institutions (80.0%) out of 40 medical colleges and schools. The median number of students’ quotas was 76 (range, 44-144), and the median number of neurology faculties was 11 (range, 4-38). Nine were in the metropolitan area, and 23 were located outside the metropolitan area.

Among the 32 institutions that responded, nine (28.1%) included neurosonology lectures in their neurology courses, with eight institutions allocating less than 1 hour. One institution did not respond within the allocated timeframes. The content of neurosonology lectures included carotid and transcranial ultrasound in eight institutions (88.9%), while neuromuscular, neurocritical care ultrasound, or ultrasound principles each accounted for one institution (11.1%) (Fig. 1A).

Among the surveyed institutions, 29 required mandatory neurology clerkships, while three offered it as an elective. The duration of the neurology clerkship was primarily 2 weeks in 25 institutions, followed by 1 week in three institutions, 3 weeks in three institutions, and 4 weeks in one institution. The most common year for students to undergo neurology clerkships was the third year of the medical course, which was offered in 20 institutions. This was followed by the fourth year in 10 institutions, and the second year in two institutions. Of the 32 institutions offering neurology clerkships, 15 (46.9%) provided ultrasound education as part of the clerkship. The duration of ultrasound education during clerkship was primarily 1 hour in 10 institutions (66.7%), followed by 2 hours in three institutions (20.0%), and 3 hours in two institutions (13.3%). The content of ultrasound education during the neurology clerkship included carotid ultrasound in 13 institutions (86.7%), transcranial ultrasound in 12 institutions (80.0%), and neuromuscular ultrasound in two institutions (13.3%) (Fig. 1B). None of the institutions offered education on neurocritical care ultrasound. The primary method of teaching was live demonstrations, utilized by 11 institutions (73.3%), followed by lectures in five institutions (33.3%), and hands-on training in two institutions (13.3%) (Fig. 2).

Among the 17 institutions without neurosonology education during their neurology clerkship, 13 (76.5%) expressed their intention to incorporate neurosonology education in the future. Among the institutions expressing their intention to provide neurosonology education, 11 institutions (84.6%) were interested in carotid ultrasound, nine institutions (69.2%) were interested in transcranial ultrasound, and one institution was interested in neuromuscular ultrasound, ultrasound principles, and neurocritical care ultrasound. Regarding the methods of education, live demonstrations were the most common, with 11 institutions (84.6%), followed by lectures in four institutions (30.8%) and hands-on training in three institutions (23.1%). In terms of the allocated time for education, 1 hour was the most common duration, selected by 11 institutions (84.6%), followed by 2 hours, which was chosen by two institutions. The survey responses are summarized in Table 1.

There were no significant differences between medical colleges and schools that provided neurosonology education during clerkship and those that did not in terms of the number of students’ quotas (median, 49 vs. 93; P=0.162), number of neurology faculties (median, 11 vs. 11; P=0.557), years since the establishment of medical schools and colleges (median, 46 vs. 38; P=0.168), or region (P=0.699) (Table 2).

In the field of neurology, the significance of ultrasonography is on the rise, paralleled by an increasing emphasis on ultrasound education [10]. Recently, institutions offering ultrasound education have been expanding to include undergraduate medical students, not limited to residents [5,10,14]. In this study, we investigated the current state of ultrasound education during pre-clerkship neurology courses and neurology clerkships in medical schools and colleges in South Korea. The survey also asked about their willingness to implement ultrasound education in neurology clerkship in the future at institutions that do not provide neurosonology education currently.

In South Korea, neurosonology education has not been widely implemented during the pre-clerkship neurology course and clerkship, and the allocated time is very limited. Of the 32 medical colleges and schools that responded to the survey, only nine (28.1%) provided ultrasound education during neurology courses, and 15 (46.9%) provided it during neurology clerkship. The allocated time was limited to 1 hour or less. According to a previous report, the challenges in implementing ultrasound education included the difficulty of adding new content to established curricula, a shortage of trained faculty, and a lack of necessary ultrasound machines and facilities for education [14].

However, comparing the state of neurosonography education across countries is challenging. In the United States, 72.6% of medical schools offer ultrasound programs, although it is unclear whether these programs include neurosonography [18]. A survey of 46 universities in Europe indicated that theoretical education was provided by 87% of institutions, while hands-on training was available in only 56% [19]. However, this study also did not clarify whether neurosonography education was included. Additionally, in a survey of 42 countries, including Europe and beyond, 30.9% reported having neurosonography programs [20]. However, obtaining detailed information on how neurosonography education is implemented in each country remains difficult.

In both the pre-clerkship neurology course and the neurology clerkship, ultrasound education predominantly covered carotid and transcranial ultrasound, with relatively limited emphasis on neuromuscular and neurocritical care ultrasound. The method of education in neurology courses is primarily centered around live demonstrations, with hands-on training conducted at only two institutions. Hands-on methods, in which students actively perform ultrasound procedures themselves are not only effective in acquiring ultrasound skills but also crucial for gaining medical knowledge [5,21]. A notable positive aspect is that among the 17 institutions where neurosonology education was not provided during neurology clerkships, 13 expressed their intention to introduce neurosonology education in the future. Nevertheless, there is a limited willingness to provide education on neuromuscular and neurocritical ultrasound. Moreover, many institutions planned to prioritize live demonstrations over hands-on, and the allocated education time was often less than 1 hour.

Studies on neurosonology education are relatively limited compared with those on ultrasound education in other specialities. This study analyzed the impact of neurosonology education on the medical knowledge of undergraduate medical students [22]. The content included transcranial Doppler, ocular ultrasound, neck scan, central line placement, and external ventricular drain placement. The presence or absence of neurosonology education was not correlated with academic performance in medical schools. Nonetheless, one limitation of the study was the insufficient duration of education, as all five topics mentioned were covered within an hour.

This study has some limitations. First, the survey was conducted with only one neurology faculty from each medical college or school. Most were neurovascular specialists. Therefore, the status of neurosonology education, other than in the neurovascular field, at each institution may not have been thoroughly captured. However, respondents were selected because they were expected to be aware of the current state of ultrasound education at their affiliated medical colleges and schools. Second, the survey response rate was 80.0% and it did not include all medical colleges and schools. Third, the study did not analyze the reasons for the absence of neurosonology education in neurology courses or neurology clerkships.

In conclusion, this study revealed that less than half of the medical colleges and schools in South Korea provide neurosonology education for undergraduate medical students, and even when provided, there are limitations in terms of time, content, and methods of education in South Korea. Therefore, it is necessary to develop a dedicated neurosonology curriculum for undergraduate medical students, particularly for neurology clerkships. It is also essential to identify obstacles in the implementation of neurosonology education in South Korea. Furthermore, it is necessary to analyze the effectiveness of neurosonology education for students during their neurology clerkship. This study will be helpful in the development and implementation of neurosonology education for undergraduate medical students.