The Use of Ultrasound in Undergraduate Medical Anatomy Education: a Systematic Review with Narrative Synthesis

Abstract

This systematic review aimed to synthesize the literature on how ultrasound is currently used in anatomy education within medical schools. A systematic search of Ovid MEDLINE, Scopus, and Educational Resources Information Centre was conducted. Thirty-four relevant unique articles were included from the 1,272 identified from the databases and analyzed via narrative synthesis. Thematic analysis generated two domain summaries: “Successful Aspects of Ultrasound Teaching” and “Barriers to Implementation,” each with additional subthemes, aimed to help educators inform best teaching practices from the current evidence base in this field.

Introduction

Understanding best practices for teaching is essential to meet the demands placed on anatomy education in the modern era. For example, in 2009, the General Medical Council of the United Kingdom (UK) published “Tomorrow’s Doctors” [1] which noted the need for medical schools to provide students with teaching focused on more holistic and clinical content [2]. This resulted in a notable decrease in anatomical teaching hours [3], despite the fact that many quote anatomy as being central to the practice of well-qualified professionals [4]. This is not a problem unique to the UK alone; the decrease in anatomical teaching can be observed globally [5–8].

Unsurprisingly, this has caused concern regarding the quality of students’ understanding of anatomy [9], leading to publications communicating the need for better understanding alternative pedagogic techniques for teaching anatomy that are both cost and time efficient, as well as being engaging and useful for the clinical student population [10]. One of the technologies suggested has been the use of ultrasound.

Ultrasound education has developed into a very popular topic of discussion within the health professions field. A search of “ultrasound education” in PUBMED reveals the number of associated publications has increased drastically over the past 20 years, from 615 in the year 2000 to 6838 in 2020. Part of this expansion has been the push to have more healthcare workers and trainees be able to perform point-of-care ultrasound (POCUS) at the patient’s bedside, reducing wait times and staffing of formal sonography in some cases [11]. This includes medical students, who are now more frequently given the opportunity to learn how to produce and interpret radiological images, including ultrasound, as a component of their education prior to specialist training [12].

As a result, there has been a large increase in publications investigating and evaluating this implementation of ultrasound training programs within medical school curricula [13, 14], including a number of systematic reviews [15, 16]. However, these articles have broader aims about ultrasound education, and do not make considerations for the nuances of undergraduate anatomy education. Additionally, the limited number of reviews on ultrasound education are quite broad, including studies with a range of curricula from different specialties, ranging from cardiology [17] to family medicine [18].

Most research into the use of ultrasound in anatomy education has been associated with single-site studies, utilizing relatively small sample populations to research student attitudes or improvement in attainment. While such varied perspectives offer insight, one could argue that ultrasound education may not be a “one size fits all” teaching methodology. This viewpoint was concluded by Lian et al. [19], who discovered that some teaching methods do not suit all ultrasound competencies. Collating and understanding best teaching practice from varied studies is of utmost importance, as using ultrasound as an anatomical educational tool may necessitate a unique financial and resource burden [20, 21], as well as time commitment within already crowded curricula [6–8]. Additionally, it is key to try to and elucidate how ultrasound anatomy teaching compares or complements other methods, such as didactic content, or cadaveric teaching.

Thus, this systematic review aimed to synthesize the available literature on how ultrasound is currently used in anatomy education within medical schools, and to present the outcomes of such use. The narrative synthesis aspect in the present work aimed to use these outcomes in order to discuss themes which could add a new perspective to ultrasound educational programs and provide best teaching practice recommendations to help guide future ultrasound teaching sessions within anatomy education.

Methods

Search Strategy

This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) framework [22]. This review involved a thorough and systematic search of English-language articles published up to April 16, 2021, with a focus on ultrasound in anatomical education.

An initial limited search of Ovid MEDLINE and EMBASE identified relevant keywords contained in the title, abstract, and headings. These keywords were then used in an extensive search of the literature using three databases: Ovid MEDLINE, Scopus, and Education Resources Information Centre (ERIC). The keywords were used across the databases relating to the target population, the intervention, the setting, and the outcome. The full search strategy for each literature database can be provided to interested readers by contacting the corresponding author.

Inclusion and Exclusion Criteria

Prior to article screening, comprehensive inclusion and exclusion criteria were drawn up following discussion and consensus from all members of the research group. All articles meeting the following criteria were eligible for inclusion in this review: all forms of research methodology, involved ultrasound in an educational capacity to teach anatomy, used a study population of medical students, and English language. There were no date or country of publication restrictions. Exclusion criteria for this review included use of a study population including others except medical students, no primary data reported, or the use of therapeutic ultrasound.

Screening of Abstracts and Full-Text Articles

All titles and abstracts were reviewed by the primary investigator (EJGK) based on the inclusion and exclusion criteria listed above. Following this, the full text for all of the included studies was ordered and reviewed independently by the primary investigator. A small sample of studies (18%) were randomly selected and also independently analyzed by two second reviewers (MT and HNM). Reviews and outcomes for these subsets of articles were then discussed with the entire research team to ensure consensus and to ensure dependability of work. Additional articles were identified via citation chaining of included articles. The entire search process is summarized in Fig. 1.

Fig. 1.

Flow diagram for the selection of studies

Quality Assessment

The primary investigator evaluated the quality of included studies using the Medical Education Research Study Quality Index (MERSQI) [23]. The MERSQI is an instrument used to assess methodological quality in medical education research. It investigates several factors, for example, study design, sampling, and data analysis. It has been previously reported to be a reliable and useful tool [24]. Quality assessment was not done as a means of inclusion/exclusion, rather to provide additional data about included studies.

Analysis

This review utilized a narrative synthesis as the primary means of analysis. This method was selected due to the heterogeneity of included studies, as previously recommended by Davis et al. [15]. Narrative synthesis refers to an “approach to the systematic review and synthesis of findings from multiple studies that relies primarily on the use of words and text to summarize and explain the findings of the synthesis” [25]. While heterogeneous in nature, the included studies still offer important insights for teaching practice in ultrasound education, making narrative synthesis an appropriate analysis method to synthesize such points. Reflective thematic analysis was conducted for this narrative synthesis in the six-step approach as suggested by Braun and Clarke [26] with the exception of the use of domain summaries in the place of traditional themes. According to Braun and Clarke, while themes contain items of shared meanings, domain summaries are said to describe a range of similarities or differences in a shared topic [27]. The primary investigator (EJGK) became familiar with the data, generated initial codes, and identified domain summaries. The same two second reviewers (MT, HNM) were involved in coding and generating independent domain summaries for a small sample of included papers; each reviewed two studies. Following this, differences in coding and generated domain summaries were discussed among reviewers and the wider research team, to improve credibility of the work. The process of identifying domain summaries was inductive and completed during the full-text analysis.

Reflexivity

This research was conducted by a group of researchers with differing baseline paradigmatic views, including post-positivists [34]. Nevertheless, a narrative synthesis utilizing thematic analysis was selected as the most appropriate means of analysis, given the research aims and heterogeneity of included studies. It is also important to note here the interest in ultrasound education the authors share, especially at the undergraduate level of medical education. While the research team hold varying ultrasound experiences, no ultrasound curricula existed at the research team’s institution during the research period. As such, this might have resulted in more of an “outside” perspective on the analysis. Finally, the research team was diverse in educational background and professional level, offering heterogeneity in views when discussing analysis.

Results

Search Results

The search of the three databases yielded an initial number of 1,272 studies, which was reduced to 1,130 after duplicates were removed. 952 of these articles were excluded during title and abstract review for having no relevance to anatomical education and/or not including medical students as study cohorts. Following full-text screening, 34 relevant articles remained that met all the inclusion criteria. Citation chaining revealed 11 more potentially relevant articles based on their titles; however, these were later excluded during abstract and full-text screening. This whole process, including reasons for study exclusion, is summarized in Fig. 2.

Fig. 2.

Flow chart of the study selection process modelled from work by Liberati et al. [28] and Moher et al. [29]

Study Characteristics

The majority of the included studies were conducted in the USA (50%, [17 of 34]), followed by the UK (15%, [5 of 34]), Germany (12%, [4 of 34]), and Australia (9%, [3 of 34]). Norway [30], New Zealand [31], France [32], Poland [33], and Canada [34] were all the country of origin for one publication each. Notably, a higher proportion of the included studies were published in recent years, for example, only one was published in 2010 [35] compared to four in 2019 [36–39]. More detailed characteristics of the included studies can be provided to interested readers by contacting the corresponding author.

Ultrasound Educational Activities

There were several lesson structures used within the included studies, the most common being a didactic introduction, with demonstration by facilitators and then a hands-on practical, or laboratory (29%, [10 of 34]). This was closely followed by a similar method but excluding the demonstration component (26%, [9 of 34]).

Of the 22 studies that reported group sizes for the hands-on component of their ultrasound intervention, only one study reported students working individually [36]. The remainder varied to a large degree, from students working in pairs [33] to groups of up to 25 [40]. Notably, the two included studies that originally had the largest group sizes during the hands-on component of the ultrasound sessions both reduced the number of students allocated to each ultrasound machine during their data collection in response to student feedback [30, 40].

Half of the included studies investigated the use of ultrasound using first year medical student participants, while ten of the included studies investigated its use with second year medical students (29%). Three further papers investigated the use of ultrasound to teach anatomy using both first and second year medical students [40–42]. Investigating the use of ultrasound to teach anatomy within the traditional “clinical years” was less notable. Only four studies researched its use within the third [31, 43] or fourth years [33, 44] of the medical curriculum.

The data concerning the ultrasound session facilitators were also extracted from each of the included studies. Of those that reported the instructors used, the vast majority included the use of clinicians as instructors (78%, [21 of 27]), while anatomy faculty (33%, [9 of 27]), near-peer students (30%, [8 of 27]), and sonographers (15%, [4 of 27]) were used less often. The percentages here add up to greater than 100% to reflect the mixed use of instructors within some teaching sessions (48%, [13 of 27]).

All 34 studies described when their ultrasound interventions occurred in relation to the involved student participants’ standard anatomy teaching. Most conducted the ultrasound sessions “alongside” or integrated with the anatomy curriculum (53%, [18 of 34]), while slightly fewer set the intervention after the anatomy teaching sessions (29%, [10 of 34]). Even fewer studies involved students using ultrasound to learn the anatomy prior to the currently used anatomy teaching practices [38, 45, 46].

Study Outcomes

In the included studies, a range of outcomes were assessed. These ranged from solely objective measurements [4 of 34], solely subjective [15 of 34], or a combination of the two [15 of 34]. Objective measures were considered as those that assessed student knowledge improvement, whereas subjective were around student attitudes.

In those that included an objective measurement [19 of 34], the results ranged from positive (53%, [10 of 19]) to neutral (26%, [5 of 19]) and mixed (21%, [4 of 19]). None of the studies that assessed an objective outcome reported only negative results.

Subjective outcomes were assessed in 30 (88%) of the 34 studies. They predominantly focused on participants’ opinions on ultrasound, the ultrasound sessions, and the implementation of ultrasound into anatomy (93%, [28 of 30]). Overall, the results of subjective measures were either positive (60%, [18 of 30]) or mixed (40%, [12 of 30]). None of the included publications reported solely negative or neutral student perceptions.

The modes of assessment for both the objective and subjective measurements are detailed in the supplemental material that can be provided by contacting the corresponding author.

Qualitative Findings

Two domain summaries were generated via the narrative synthesis: “Successful Aspects of Ultrasound Teaching” and factors noted as “Barriers to Implementation” of ultrasound into the anatomy curriculum. The domain summary “Successful Aspects of Ultrasound Teaching” investigated the good teaching practices that tended to correlate to a positive outcome, for example, student satisfaction with the ultrasound session, whereas the domain summary, “Barriers to Implementation,” related to problems encountered or reported to be likely encountered by authors during the creation of their teaching sessions and future implementation into the anatomy curriculum. The extensive results of the thematic analysis, including a larger quantity of illustrative quotes, can be provided to interested readers by contacting the corresponding author. All key elements and subthemes are shown in Table 1, including some illustrative excerpts from included articles.

Table 1.

Table providing description and illustrative examples of the subthemes generated during thematic analysis

Domain summary/theme	Subtheme description	Examples (quotes from included articles)
Successful aspects of ultrasound teaching
Stakeholder attitudes — student perception of ultrasound	Medical students’ viewpoints on ultrasound within the medical curriculum and what they particularly like and dislike about the educational resource	“…students of all groups often reported that the dynamic and real-time nature of the imaging provided them with a better understanding of how the anatomical structures “work” and allowing fostering of strong links to physiology…” [35]
Stakeholder attitudes — year of study	How year of study and potential prior anatomical experience affected student perception of ultrasound	“Students with high prior anatomy experience suggested ultrasound may be better taught on their clinical days rather than as a part of anatomy curriculum. This may be because these students were more comfortable with normal anatomy seen on ultrasound images and preferred to spend more time on pathology and linking patients’ clinical presentations to abnormal findings on the images.” [42]
Stakeholder attitudes — cognitive load	Findings associating increase in cognitive load with student viewpoints on using this technology as an imaging tool to further their anatomical understanding	“[Comments from participant]: ‘Most difficult part of me is getting used to the orientation on the screen and correlating it with probe orientation.’” [34] “…the minimal introduction provided to the learners may be sufficient to mitigate significant harm induced by image interpretation during participation in ultrasound-facilitated sessions.” [34]
The structure and implementation of pedological approaches — group size	How group sizes within the educational activity affected study outcomes	“…students need to see the probe position on the volunteer and the resultant image in the same field of view, so that students can integrate information from all elements of the demonstration; in large groups, it is likely that only students close to the demonstration can see all elements of it, which may explain students’ desire for smaller groups.” [40]
The structure and implementation of pedological approaches — relation to normal anatomy	Findings on timing/placement of the ultrasound sessions within the medical curriculum and how this affected study outcomes	“Students favored having the sessions later-on in the teaching of the course, because they found the sessions more interesting after they already were exposed to the anatomical topics.” [47]
The structure and implementation of pedological approaches — educational activity	Details on the structure of the ultrasound sessions and whether the inclusion or exclusion of some activities affected study outcomes	“The second-year students were very keen to have background information to guide them in the differentiation of tissue types so that they did not have to rely on their “imagination” to interpret the image.” [41] “Our experience revealed that teachers and students found more relevance in the practical phase of the session, which combined education and entertainment. This part appeared to best stimulate the interest of students and encourage their desire to deepen their knowledge of anatomy.” [32]
Impact of facilitators — type of teacher	Use of different types of facilitators within the ultrasound sessions and the effect on study outcomes	“In this study, we utilized a physician to teach the relevant cardiac anatomy using a clinical imaging modality; this in itself may promote retention of cardiac anatomy as the students aim to become accepted as part of the clinical community.” [45] “…Minimally instructed student-teachers can be employed to teach anatomically skilled students, whereas medical experts should be used in earlier stages of anatomical education…One aspect might be the steep learning curve and the complexity of MSUS [musculoskeletal ultrasound].” [48]
Barriers to implementation
Lack of ultrasound equipment/cost	Prominent issues in ultrasound curriculum design; particularly, a lack of ultrasound resources	“Tutors reported that access to more machines would enable further curriculum development (in teaching and assessment).” [40] “…the budget of many anatomy departments may not be large enough to support purchase of the machines.” [35]
Busy medical curriculum	Difficulties in implementing an ultrasound curriculum in an already arguably full medical curriculum	“…the addition of new instructional sessions may require that time is reallocated from other components of anatomy education” [49]
Teacher availability	Issues in recruiting and providing adequate training to ultrasound facilitators	“…the number of instructors required to establish an ultrasound curriculum will undoubtedly vary among medical schools – based on a number of factors, including class size, available machines, room availability, and others…” [21]

Quality Assessment

All included studies were assessed for quality using the MERSQI. The mean score of this was 9.78 of a possible 18, a median of 9.5, with a range between 6 and 14.5. The most common study design was a single group post-intervention test (65%, [22 of 34]), followed by a randomized control trial design (18%, [6 of 34]). It is important to add that a majority of the included studies lacked a control group (71%, [24 of 34]). Sample sizes of the included studies were consistently over 100 medical students (71%, [24 of 34]). Evidence of validity of the evaluation instrument was seldom reported (32%, [11 of 34]), with content validity being most common (29%, [10 of 34]) and relationship to other variables being least common [50]. Unfortunately, a funnel plot could not be generated due to heterogenicity of the data.

Discussion

This systematic review identified 34 relevant studies that investigated the use of ultrasound to aid the acquisition of anatomical knowledge in a medical student population. Thirty of the studies assessed subjective outcomes, including student attitude to the introduction of ultrasound into the anatomy curriculum. The investigation of more objective outcomes, such as improvement in anatomical exam scores, was assessed in only 19 of the papers. Although the included studies were generally of “modest quality” by the standards of the MERSQI, the results of these papers were mostly positive and supported the introduction of ultrasound into the anatomy curriculum. Further, findings and conclusions prove insightful for the development and delivery of anatomy-related ultrasound sessions. The two domain summaries generated: “Successful Aspects of Ultrasound Teaching” and factors reported as “Barriers to Implementation” of ultrasound into the anatomy curriculum guide the discussion below.

Successful Aspects of Ultrasound Teaching

Stakeholder Attitudes

Most of the included studies reported that students had a positive perception of the use of ultrasound within anatomical education. For example, the Swamy and Searle [51] study had one student highlight how ultrasound sessions are “‘…useful as they will be will be applicable as our future as doctors’.” This is one criticism of traditional methods of teaching anatomy, such as prosections, where students are not able to recognize the clinical significance of learning anatomy during their preclinical years [4, 52, 53]. Clinical contextualization is important in medical education as it has been postulated that teaching with this focus can convey to students why learning anatomy is important to their future practice, thus facilitating long-term knowledge retention [54]. Students want a new teaching modality to be relevant not only to their future practice but also to their current studies. Both Sweetman et al. [41] and Moscova et al. [42] reported that while students in their preclinical years were happy with simply visualizing anatomical structures, those who had further progressed into the medical degree felt they wanted to see more pathological images and the clinical significance of these findings.

The Structure of the Pedological Approaches

It is interesting to note that some of the included studies omitted the use of a demonstration. In the studies that lacked a demonstration, it is reported that students felt they would have benefited from more teaching in the ultrasound technique and image interpretation [41, 55]. Where a demonstration was used, students highly valued it [32, 47, 50, 56, 57]. Although seemingly omitted due to time pressures, it has been previously published that medical students have the ability to adapt to new technology quickly [58–60]. Seemingly, only a short introduction to the ultrasound fundamentals and equipment would be necessary for students, especially considering that the focus of the teaching sessions in this review was to further anatomical knowledge, not teach students how to perform clinical assessment with ultrasound. These findings suggest that it may be beneficial to reduce didactic time in sessions, instead supplementing it with a scanning demonstration, to support student attention and feedback.

As reported by Hammoudi et al. [32], both teachers and students found the hands-on teaching format, where students were able to use the probes to produce ultrasound images, to not only be the most enjoyable part of the ultrasound session but also the most appropriate in terms of conveying clinical relevance and anatomical knowledge. The benefits of hands-on instruction were also demonstrated by Knudsen et al. [61] who reported that after 6 weeks, students who had hands-on training were able to answer questions relating to image interpretation much faster than those who did not have hands-on experience. This aligns with previous research suggesting hands-on education might train pattern recognition skills, help students retrieve prior knowledge, and improve students’ self-confidence with their answers more effectively than those with no hands-on education [62]. Indeed, there has been a push for educators to introduce more pattern recognition training into the medical curriculum [62–65]. Consequently, these results suggest that it would be advantageous to implement further hands-on teaching in ultrasound sessions to support student anatomical learning. However, it would be important to consider the balance of hands-on experience with anatomy focus on sessions.

Linked with this, students often felt that the group sizes were too large, particularly in hands-on aspects of the teaching sessions, to allow them to truly benefit from the implementation of ultrasound into the anatomy curriculum [30, 34, 40, 42]. Although group size has not been investigated further within the ultrasound teaching context, it has been for students on clinical rotations. A study by Ofei-dodoo et al. [66] discovered that students similarly preferred smaller group sizes. The students highlighted several advantages of having smaller group sizes, including more contact times with both patients and clinicians, and more participation confidence [66]. Some of these results are naturally transferable to the topic of this review, given the potential similarity in clinical skills and ultrasound sessions; however, further research into group sizes within the context of ultrasound and anatomy teaching would be required.

Implementing Ultrasound into the Anatomy Curriculum

Longitudinal integration of anatomy within the medical curriculum has been and continues to be widely supported by clinicians from all specialties [67, 68]. This point was also argued by several of the authors of included studies. They posit that ultrasound should be a longitudinal skill and therefore, introduced early and revisited across the years [21, 33, 37, 61, 69].

The most common placement of the ultrasound sessions was alongside relevant anatomy curriculum, with only three studies implementing ultrasound prior to anatomical teaching practices already within institutions’ curricula [38, 45, 46]. Results from the thematic analysis demonstrate that students felt they would have benefited further if interventions had occurred after prior anatomical teaching “…because they found the sessions more interesting after they already were exposed to the anatomical topics” [47]. Knobe et al. [70] further voice this notion, stating that the effectiveness of an ultrasound session is dependent on students having some prior anatomical knowledge. This aligns well with the educational theory, constructivism, whereby learners build new knowledge upon the foundation of previous learning [71, 72]. Therefore, this review supports the notion that ultrasound sessions should be implemented after standard anatomy teaching and act as a recap of anatomical knowledge.

The Impact of Facilitators

Although different types of facilitators had different strengths, they were generally enjoyed by the student participants from studies, including the use of near-peer students noted in numerous works [21, 44, 50, 55, 69, 73–75]. Most of the included studies were from the USA, where near-peer assisted learning is more prevalent [76]. This is thought to result from increased motivation and stress, knowing that a higher level of knowledge is needed to teach a topic to others [77]. Consequently, the findings of this review support that near-peer students, with appropriate prior training, can effectively teach ultrasound in an anatomical context. This is congruent with findings present in the wider literature on the effectiveness of near-peer tutors [78–83].

Extensive training of facilitators prior to the session was often required and reported in numerous included studies as a barrier to the implementation of ultrasound into anatomy curricula [40, 47, 55, 73, 75]. Although this supports the notion that those with appropriate training can use ultrasound to highlight anatomy, there are conflicting views in the ultrasound education community. Hoppmann et al. [84] and Rao et al. [85] conclude that an ultrasound curriculum should be delivered by those with extensive experience using ultrasonography in the clinical setting, which contradicts reliance on anatomists and near-peers. To ease this conflict, course designers could aim to have more engagement with the sonography workforce and seek advice from professional bodies. Additionally, clinical collaboration could be targeted as some specialties regularly use ultrasound in practice. This would ensure sufficient expertise is available to allow students to recognize the utility of ultrasound in visualizing anatomy.

Barriers to Ultrasound Implementation

The two most reported barriers to implementation of ultrasound into the medical curriculum were the cost and lack of ultrasound equipment in many medical schools, and a lack of space in the already congested medical curriculum.

Although reducing in cost and relatively inexpensive in comparison to other imaging modalities [86], ultrasound continues to be unavailable to many anatomy departments. One suggestion to limit the potential problem of cost and lack of ultrasound equipment could be for medical schools to work more in tandem with ultrasound manufacturers to guarantee the availability of required resources and equipment. In reality, this is already standard practice in a number of medical schools in the USA [39, 87, 88] and Australia [42]. Nonetheless, should resources and suitable facilitators continue to be lacking, the use of a demonstration by a clinician and anatomy faculty in a large lecture theater could be employed. Indeed, Stringer et al. [31] found this teaching method to be effective in stimulating student interest in anatomy and ultrasound. However, the authors noted that some students struggled with image orientation and acknowledged that hands-on experience may help to combat this [31]. Alternatively, Smith et al. [75], who were similarly concerned about the funding of their anatomy department and the implications of introducing ultrasound sessions, were able to contact and borrow the required machines and resources from local simulation and emergency departments. All of these could be a potential solution should educators be concerned about the heavy financial and resource requirement of implementing ultrasound into the anatomy curriculum.

The problem associated with a busy medical curriculum is perhaps more difficult to solve. Time allocated to anatomy education within the medical curriculum has gradually decreased over the years, with Turney [3] previously suggesting this had fallen below a safe level. By implementing ultrasound into the already full anatomy curriculum [6, 7], other learning opportunities will be lost, for example, allocation of student learning time with traditional learning resources such as prosections. Consequently, this could have the effect of proliferating the problem of medical student lack of anatomical knowledge. This is a perennial problem associated with implementing any new teaching method into the medical curriculum and will likely continue to be in the future.

Limitations and Contradiction with Other Literature

Firstly, in conducting a systematic review, there is always the possibility of missing other potentially germane articles. In an attempt to mitigate this problem, three different databases were searched and citation chaining was conducted.

Second, the included studies were conducted in several different countries with different entry requirements for the medical degree, which affects the potential prior knowledge and experiences of the student populations [89–91]. This does not discount the research but is an important consideration point. Educators should keep this in mind, and consider their personal curricular circumstances, in their own application of this review’s findings.

Finally, another potential limitation encountered was the heterogeneity of the data. The studies included in this systematic review used various methodological designs and assessed a wide range of outcomes, despite being focused on anatomy education. Consequently, a meta-analysis could not be conducted. As a result, this systematic review includes descriptive analysis of the quantitative data, and the use of thematic analysis for a narrative synthesis of findings. While narrative synthesis may be viewed as “less rigorous” from a strict post-positivist perspective, or inferior to meta-analysis, this form of analysis can provide equally valuable perspectives from this particularly heterogenous literature, particularly for research aims like those in the present work.

This is particularly notable when comparing the present review to other recent literature in this field. Interestingly, a recent similar systematic review, also surrounding ultrasound education, came to different conclusions in their interpretation of their included articles [16]. Feilchenfeld et al. contended the introduction of ultrasound into the medical curriculum, as they concluded that the resources required for ultrasound implementation were not justified when factored against objective measurements. They argue that because medical education research is conducted by enthusiastic researchers, they will have a bias towards the study intervention and lack the ability to report the consequences of implementing such interventions into the medical curriculum. As a result, negative implications are not recognized until after significant resources have been expended to produce a change in the curriculum [16].

However, this perspective does not consider the tenets of confirmability that shape qualitative inquiry, rather than notions of objectivity, and that may be beneficial to combat perceptions of “bias” within medical education. Typically, a reflexivity section is provided to allow the reader to question the positionality under which the researcher has interpreted the data [92]. Indeed, perhaps all research should aim to include such, although this was not noted in many of the included studies of this review. Nevertheless, a number of the included articles’ aims were to describe their curricula and report the resources necessary for their use, taking a pragmatic and transparent approach [21, 88].

The present review has a number of different methodological approaches compared to the review conducted by Feilchenfeld et al. [16], which only included 8 studies specifically related to anatomical education. Furthermore, Feilchenfeld et al. [16] consider a non-statistically significant difference in student anatomical knowledge improvement between ultrasound and the currently approved “gold standard” pedagological approach, with the latter being superior. However, such non-statistically different results suggest that ultrasound may be on par with the current gold standard teaching method.

Additionally, while Feilchenfeld et al. [16] are correct to note that the articles surrounding ultrasound education are highly heterogenous, such heterogeneity of the articles simply highlights that ultrasound is being utilized and studied in a diverse range of settings. There are undoubtedly limitations to the studies that exist in this field; however, the narrative synthesis methodology in the current study examines the included studies beyond simply their findings to be able to inform educational practice. Still, institutions can thus weigh the proposed advantages against barriers for themselves, while considering best practice suggestions synthesized from the review above.

Conclusion

To conclude, this systematic review identified 34 relevant studies that assessed outcomes related to the use of ultrasound within the medical curriculum to teach anatomy. Despite some variation in study design and quality, the results of these studies indicated that students enjoyed the use of ultrasound to aid the acquisition of anatomical knowledge. To the anatomy educator looking to either start an ultrasound program or improve their existing program, six key “take-aways” from this review are as follows:

• Ultrasound should be taught alongside standard anatomy teaching, as a supplemental experience that is “introduced early, and revisited often.”

• The learning objectives for ultrasound activities in preclinical years should appear clinically relevant to students but focused on immediate anatomy education — students need to visualize “normal” to be able to then understand “abnormal.”

• Individuals conducting anatomy education (ultrasound) research need to demonstrate more transparent reflexivity, to better frame understanding of activity implementation.

• Anatomy ultrasound curricula should prioritize hands-on activities, with reduction of didactic time, supplementing it with scanning demonstrations, when used.

• With appropriate training, “near-peer” student instructors for anatomical ultrasound sessions can be very effective.

• Cost, equipment access, and “space” in medical curricula are the biggest barriers to more widespread integration of ultrasound within anatomy education, but collaborations may help remedy this.

Furthermore, future studies in this field should focus less on student perception of ultrasound, which have been shown to be overwhelmingly positive, and conduct more rigorous investigation of whether the addition of ultrasound to standard teaching practices furthers student anatomical knowledge to a statistically significant degree, and the potential longitudinal effects. But for now, by considering these best practice points among others identified in this review, it is the hope that ultrasound education will continue to make great advances in its role within anatomy education.

Author Contribution

Edward J. G. Kenny (EJGK) and Angelique N. Dueñas (AND) contributed to the review design and conception. Material preparation and data collection was performed by EJGK. Data analysis was performed by EJGK, with assistance from Haran N. Makwana (HNM) and Maria Thankachan (MT). The first draft of the manuscript was written by EJGK, and all authors commented on previous versions of the manuscript, with more revisions from AND and Lauren Clunie (LC). All authors read and approved the final manuscript.

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Declarations

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Conflict of Interest

The authors declare no competing interests.