Cost Effectiveness

Cost is another component to assess when comparing two different modalities. It is an issue for many patients, as the patients are always concerned with the money required to use in the event where visitation to the hospital is inevitable. Cost-effectiveness in digital imaging comprises of direct and indirect effects (Sailer et al., 2015). Hence, when accessing the cost-effectiveness, it is essential to understand that the imaging test must provide added value. Otero et al. (2008) state that the term cost-effectiveness is not just the amount paid for the examination, it also takes into consideration the other causes like the need for further examinations to confirm the diagnosis.

In Tan Tock Seng Hospital, a Singapore government hospital,
LUS is not frequently done. However, the price of a CXR is lower than an LUS scan, showing $12.15 and $50 respectively for subsidised patients. On the other hand, showing $50 and $150 respectively for non-subsidised patients. Hence, many people believe that CXR is a better option when compared to an LUS scan. This explains the reason why chest radiograph remains the first-line imaging test to evaluate Pneumonia in Singapore.

However, Jones et al. (2016) have debunked this statement and justified that the overall cost of LUS is equivalent to a CXR, or in fact in most cases, is much lower than CXR. In this randomized study, 191 pediatric patients, suspected of pneumonia, from birth to age 21 years, were enrolled in this study. 103 patients did an LUS followed by a CXR for additional verification (investigational group), and 88 patients did a CXR followed by an LUS (controlled group). The overall study noted that there was a 38.8% reduction in CXR in the investigational group. However, when compared to the controlled group, there was no reduction seen. Hence, in this study, the reduction in CXR led to an overall cost reduction of $9,200. Since this was a randomised and controlled trial that involved radiologists blinded to clinical examination findings, it increases the validity of the research. Furthermore, Andronikou et al. (2017) stated that in the event when a CXR is non-contributory, an advanced imaging modality is required for the evaluation of diagnosis. Therefore, contributing to an additional cost that the patient has to pay.

Thus, the studies mentioned above have reflected that LUS has a better cost-effectiveness when compared to a CXR.
However, LUS is not done as the first-line imaging test, as patients would favor a cheaper option like the CXR. Moreover, other factors like the time of the scan have also made an impact on the decision patients have when choosing a choice of modality.

3.4. Accessibility

Having access to medical imaging is also important, as it helps to optimise patient care (World Health Organization, 2012c). Thus, it is important to take into consideration the ability of the patient to be transported to the radiology department (Amanullah, 2015).

Pneumonia patients are usually confined to bed due to their weak immune system, which makes it tough for their body to fight germs. Therefore, these patients are subjected to invasive monitoring equipment and careful monitoring. When evaluating Pneumonia, a CXR examination is the first-line imaging modality. However, it is difficult to use on bedridden patients or ambulatory patients (Cardinale et al., 2012). As a result, when compared to the US, CXR has a restricted access to the patients. Nonetheless, portable X-ray machines are available clinically, and an Anterior-Posterior (AP) portable CXR is usually done in a supine or semirecumbent position for bedridden patients (Loeb et al.,
2006).

However, despite its availability clinically, it is not recommended, as there is a challenge to do a left lateral using portable. In a normal lateral radiograph, the vertebral bodies appear progressively darker from superior to inferior due to the attenuation of the x-ray beam. Hence, a lateral chest view is particularly useful if the chest radiograph shows the ‘spine sign’. It is a sign when the air in the lower vertebral body is displaced by an increased density material such as consolidation or mass, thus, appearing more radioopaque (McDonald et al., 2009). Appendix 11 shows a comparison between a normal lateral plain radiograph and a lateral view with an opacity projected over the lower vertebral body. Therefore, portable x-ray do not have the ability to do a left lateral x-ray, making it difficult to evaluate a left lower lobe pneumonia (Feigin, 2010). Moreover, portable x-ray could result in a backscatter artifact, as the cassette shielding is minimized to reduce the weight of the cassette (Bushong, 2013). Hence, artifact appearance can affect the image quality, compromising the accuracy of a CXR (Jensen & Meyer, 2015; Koenig & Truwit, 2006). In addition, Silverstein (2016) identified that approximately three-quarters of the world population do not have access to radiography imaging.

On the other hand, US is a diagnostic tool that does not require optimal patient positioning from the patient, and it portable. It is easily done at the patient’s bedside, following a proper diagnosis (Rahmati et al., 2015). Hence, showing that LUS has a better accessibility, making it a valuable tool in challenging situations, such as in the ED, ambulance or at the bedside of a critically ill patient (Sartori & Tombesi, 2010).

3.5. Operator Competency

Although US is highly accessible, a few research have expressed concerns over the use of US, as it is operator dependent, and this may lead to a decrease in accuracy, as well as a longer examination time for the patient (Cipriani & Ghittoni, 2015; Skaarup et al., 2017).
However, Pereda et al. (2015) and The University of Melbourne (2017) expressed that LUS is a basic sonographic technique that is easy to learn. Furthermore, it is less technically demanding as compared to other sonographic examinations, and it is demonstrated that beginners with approximately 7 hours of training were able to obtain high sensitivity (98%) and specificity (95%). Although the study conducted by Pereda showed high sensitivity and high specificity, the study was performed in a single centre. Therefore, narrowing the external validity of findings, increasing the bias. Furthermore, according to Eisen et al. (2010), LUS is a newly developed tool, hence, there is lack of professionals trained in using this
method.