Introduction

The history of ultrasonography (USG) dates back to the beginning of the 19th century when physical principles that form the basics of this imaging method were discovered. As early as in 1822, Jean-Daniel Colladen analyzed the speed of sound in the waters of Lake Geneva using an “underwater bell.” In 1877, Lord Rayleigh proposed a theory of acoustic wave propagation, and in 1880 Pierre and Jacques Curie discovered the piezoelectric effect⁽¹⁾. The accomplishments of physics in this field have been explored for nearly 200 years, and new imaging techniques have been introduced: ranging from ocean bottom mapping, through the creation of a reflectoscope, to examining internal organs in people. These advances have allowed us to diagnose lesions in the brain, heart, parenchymal organs, vessels or even lungs and bowels. This method is continuously perfected and more and more eagerly used by clinicians of various specialties. Thanks to its simplicity and when its basic principles have been mastered, ultrasonography becomes a tool that can be used in everyday medical practice and, more importantly, also in general practitioner (GP) offices. An ultrasound scanner is more and more frequently used as a stethoscope of the 21st century^(2–4). The widespread usage of this method in primary health care would combine physical examination, interview and imaging, thanks to which redundant diagnostic processes could be avoided in certain cases, and patients would be provided with faster diagnoses⁽⁴⁾. Point-of-care US examination, i.e. a scan performed by a doctor who is not a radiologist in their office or at patient's bedside in order to identify a specific clinical problem, enables one to practice modern and effective medicine⁽²⁾.

Aim

The aim of this paper is to review the Polish medical literature pertaining to the usage of ultrasound imaging in general practice as well as to present advantages, disadvantages and utility associated with conducting ultrasound examinations by primary care physicians based on selected publications.

Material and methods

The material for this review consisted of 15 articles published in 1994–2013 in the following medical journals (Tab. 1):

The publications were found in the following data bases:

The key words used while searching for the publications were: ultrasonography, general practitioner, ultrasonography family physician, ultrasonography usage, ultrasonography office, ultrasound imaging, family medicine, medical imaging

Results

Fifteen publications were found in the available data bases. Five of them present the usage of ultrasonography by a primary care physician for general purposes^{(1, 2, 5–7)}, 4 discuss the usage of abdominal scans^(8–11), 3 – imaging of the neck and lymph nodes^{(4, 12, 13)}, 1 – lungs⁽³⁾, and 2 discuss its usage for specific disease entities^{(14, 15)}. Moreover, the role of ultrasonography is discussed with respect to the following conditions: carpal tunnel syndrome, polycystic kidney disease, thyroid lesions, enlarged lymph nodes, palpable neck tumors, abdominal pain and auscultatory changes in the lungs.

Individual articles draw attention to general advantages of ultrasonography, particularly in terms of its usage in the office of a general practitioner. The authors emphasize its positive role in primary diagnosis and its usefulness but also problems concerning its application. The publications mention issues associated with training doctors in terms of basic principles of ultrasonography, equipment applied and financial aspects (Tab. 2).

These results demonstrate that the greatest advantage of performing ultrasound examinations in general practice is the fact that it is a good screening tool in the diagnosis of numerous conditions. The authors frequently underline shorter duration of a diagnostic process as well as safety, non-invasiveness, rapid examination, low cost and ready accessibility. One fifth of the publications mention an important aspect of US uniqueness as the only clinical imaging modality. By combining the interview, physical examination and real-time imaging, ultrasonography constitutes a whole, which can be clearly used in general practice^(2–4). Additional advantages of this modality are: increased value of examination and quality improvement of daily medical care (Tab. 3).

The authors do not list many disadvantages of ultrasound imaging. Some emphasize that it cannot be a solitary examination, has to be combined with clinical assessment and, without a doubt, requires experience⁽⁸⁾. Moreover, it is also noted that patients must be adequately prepared for abdominal or pelvic scans. One of the articles draws particular attention to high costs of modern techniques, such as elastography or contrast-enhanced ultrasound, which are not needed for a basic screening scan⁽¹⁾ (Tab. 4).

Discussion

An ultrasound examination is one of the most common additional examinations. It is the first choice in most diagnostic algorithms used by a general practitioner. The action of ultrasounds is considered safe – to date, they have not been proven negative or harmful. That is why examinations can be repeated many times and the course of a given disease can be closely monitored⁽⁹⁾. Moreover, US is non-invasive, painless, readily accessible and less expensive than other imaging examinations^{(8, 12, 14)}. It is characterized by high specificity and sensitivity⁽²⁾. By contrast with CT and MRI, it enables dynamic real-time imaging, thus facilitating image interpretation. Stable images, however, are used to illustrate changes and create documentation but are not the main basis for establishing diagnoses⁽⁸⁾.

Ultrasound imaging enables direct contact between the doctor and patient during the examination, which can be conducted in various planes and patient positions. This is particularly useful in patients in a serious general condition, in whom conducting lung US is easier than chest X-ray⁽³⁾.

Due to technological advances, there is equipment of better and better quality, and the portability and compactness of certain models enables doctors to reach patients during home visits, e.g. bedridden ones, disabled or elderly etc.⁽³⁾

US is used for specialist diagnosis, screening or procedures, such as abscess drainage or intraarticular administration of medications⁽²⁾. It seems that it can play a role in periodical check-ups, enabling patient monitoring⁽³⁾.

The authors of the analyzed publications draw attention to various positive effects associated with using ultrasonography by primary care physicians. A general practitioner knows the patient, is familiar with clinical signs, medical history and has access to results of all additional examinations, including US, thanks to which they can assume a global attitude to the patient's disease^{(3, 12)}. A US examination conducted in a GP's office would allow rapid diagnoses to be established and immediate decisions to be taken concerning whether or not the patient requires specialist consultation or hospitalization⁽⁵⁾. This is particularly important in life-threatening conditions⁽³⁾, such as pneumothorax, pneumonia, dyspnea or presence of fluid collections in body cavities. A US examination could shorten the time needed to confirm or rule out clinical signs^{(3, 13)}, which would enable the identification of silent pathologies (e.g. impalpable thyroid nodules or polycystic kidney disease) ^{(13, 15)}, reduce patient's stress and shorten the time of waiting for a consultation with a specialist. Moreover, a point-of-care US examination conducted by a family physician⁽²⁾ does not prolong the visit since, e.g. the duration of lung examination with ultrasound is comparable to that with a stethoscope⁽³⁾. The term point-of-care ultrasonography means carrying out and interpreting ultrasound findings while making therapeutic decisions in order to confirm a suspicious pathology. The GP's knowledge concerning US would reduce the number of inadequate referrals and improve correct interpretation of results⁽²⁾.

Photographic documentation would enable primary care physicians to make rapid comparisons between current and previous US results⁽³⁾. This would enable detection of subtle lesions, which could prove crucial in increasing the detectability of diseases in their early stages. Additionally, a primary care physician could periodically monitor healthy patients and control the efficacy of treatment or follow changes resulting from the disease⁽¹⁰⁾. Thanks to screening ultrasound examinations, an early diagnosis of a disease can contribute to a decrease in the percentage of advanced conditions that lead to disability. The problem of late carpal tunnel syndrome diagnosis can serve as an example⁽¹⁴⁾.

It must be remembered that ultrasound imaging is an additional examination and it should not be the only basis for decision-making⁽⁸⁾. US is characterized by certain limitations, e.g. it makes it possible to detect a cancerous lesion, but it cannot evaluate it in terms of malignancy⁽¹²⁾.

The value of ultrasound mainly depends on three factors: equipment, patient and examiner.

When selecting ultrasound equipment, one should bear in mind the guidelines of the Polish Ultrasound Society since the age and class of equipment affect image quality⁽⁹⁾. Moderate-class equipment is completely sufficient for general practitioner offices.

Moreover, the quality of an examination is affected by the general condition of a patient, the condition of abdominal wall (wounds, scars, stretch marks) and proper preparation of patients by adequate diet, antiflatulent agents (intestinal gas can make abdominal structures less accessible) as well as proper degree to which the urinary bladder is filled⁽⁹⁾. Insufficient knowledge of primary care physicians concerning ultrasonography, or sometimes the lack of such knowledge, results in inaccurate referrals and poor skills in interpreting US findings⁽⁸⁾. The author of one article, published in 2002, emphasizes that skills of doctors who perform US examinations in accordance with the guidelines of the Polish Ultrasound Society and Polish Medical Society of Radiology should be confirmed with adequate certificates⁽⁹⁾. A US examination is always subjective, and its results and further diagnostic process depend on qualifications and experience of the examiner and their professional approach⁽¹²⁾. That is why it is concluded that the issue of ultrasonographic education is crucial.

Jakubowski emphasizes that acquiring the ability to conduct ultrasound examinations properly requires a systematic approach, everyday training under professional supervision and the usage of appropriate equipment. According to Jakubowski, this takes at least 12 months⁽⁶⁾. Despite such a long period of time needed to master the specifics of ultrasound imaging, a survey conducted by Latalski, Woźnica and Bełtowska among doctors demonstrates that there is a considerable demand for such courses⁽⁷⁾. They would enable doctors to perfect their skills in interpreting US findings in the most common pathologies encountered in a GP's office on a daily basis. Moreover, GPs assess their own knowledge as insufficient and, therefore, they must frequently seek assistance of more experienced colleagues. They believe that such courses should be primarily practical and conducted by qualified ultrasonographers⁽⁷⁾. Many surveyed doctors draw attention to high costs of specialist trainings⁽⁷⁾. Furthermore, a comment to the publication of Sowińska-Neuman includes the opinion that the financial aspect should encourage general practitioners to conduct US examinations in their own offices. Performing such scans is less expensive than referring patients to other centers⁽¹¹⁾. Moreover, doctors should possess knowledge about available ultrasound equipment in order to be able to purchase adequate systems⁽¹⁾.

Conclusions