Is point-of-care ultrasound disruptive innovation? Formulating why POCUS is different from conventional comprehensive ultrasound

Background

Point-of-care ultrasound (PoCUS) is spreading throughout Emergency Medicine, Critical Care and Pre-hospital Care. However, there is an underlying inherited conflict with the established specialties performing comprehensive examinations. It has been stated that PoCUS is disruptive innovation. If this is true the definition might open up for a new perspective on differentiating comprehensive ultrasound from PoCUS. PoCUS in the light of disruptive innovation is a different perspective on ultrasound that has not before been academically scrutinized.

Methods

In this paper we investigate if PoCUS is in fact disruptive innovation. This is done by comparative analysis with the point of departure in disruptive innovation theory known from the business world.

Results

We find that a disruptive innovation process is happening. This new knowledge allows us to put forward advice for the stakeholders in the field of ultrasound. It also allows us to challenge the conventional pyramid of expertise used to describe different types of ultrasound. The perspective of this paper is mutual understanding of similarities and differences between conventional and point-of-care ultrasound. Only with this understanding the stakeholders can collaborate and use the full spectrum of ultrasound for the benefit of the patient.

     

Can medical learners achieve point-of-care ultrasound competency using a high-fidelity ultrasound simulator?: a pilot study

Background

Point-of-care ultrasound (PoCUS) is currently not a universal component of curricula for medical undergraduate and postgraduate training. We designed and assessed a simulation-based PoCUS training program for medical learners, incorporating image acquisition and image interpretation for simulated emergency medical pathologies. We wished to see if learners could achieve competency in simulated ultrasound following focused training in a PoCUS protocol.

Methods

Twelve learners (clerks and residents) received standardized training consisting of online preparation materials, didactic teaching, and an interactive hands-on workshop using a high-fidelity ultrasound simulator (CAE Vimedix). We used the Abdominal and Cardiothoracic Evaluation by Sonography (ACES) protocol as the curriculum for PoCUS training. Participants were assessed during 72 simulated emergency cardiorespiratory scenarios. Their ability to complete an ACES scan independently was assessed. Data was analyzed using R software.

Results

Participants independently generated 574 (99.7%) of the 576 expected ultrasound windows during the 72 simulated scenarios and correctly interpreted 67 (93%) of the 72 goal-directed PoCUS scans.

Conclusions

Following a focused training process using medical simulation, medical learners demonstrated an ability to achieve a degree of competency to both acquire and correctly interpret cardiorespiratory PoCUS findings using a high-fidelity ultrasound simulator.     

Does the echogenicity of focal liver lesions on baseline gray-scale ultrasound interfere with the diagnostic performance of contrast-enhanced ultrasound?

The objective was to evaluate whether the echogenicity of focal liver lesions (FLLs) on baseline gray-scale ultrasound (US) interferes with the diagnostic performance of contrast-enhanced US (CEUS) for small FLLs. Three-hundred and eighty-eight patients were examined by real-time CEUS using a sulfur hexafluoride-filled microbubble contrast agent. The images of 114 hyperechoic lesions, 30 isoechoic lesions and 244 hypoechoic lesions were reviewed by two blinded independent readers. A five-point confidence level was used to discriminate malignant from benign lesions, and specific diagnoses were made. The diagnostic performances were evaluated by receiver-operating characteristic (ROC) analysis. The diagnostic performances of CEUS on hyperechoic lesions in terms of the areas (Az) under the ROC curve were 0.987 (reader 1) and 0.981 (reader 2), and were 0.987 (reader 1) and 0.984 (reader 2) for iso- and hypoechoic lesions, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 87.0–95.9%, 93.1–100%, 88.6–100%, 70.0–97.1% and 90.0–95.1%, respectively. The echogenicity of FLLs on baseline gray-scale US does not appear to interfere with the diagnostic ability of CEUS for small FLLs.     

Can ultrasound help to define orthopedic surgical complications?

This article aims to describe and illustrate the usefulness of ultrasound in detecting complications of orthopedic implants, metal fixation devices, and other surgical material, with an emphasis on soft-tissue pathology.     

Imaging the premature brain: ultrasound or MRI?

Neuroimaging of preterm infants has become part of routine clinical care, but the question is often raised on how often cranial ultrasound should be done and whether every high risk preterm infant should at least have one MRI during the neonatal period. An increasing number of centres perform an MRI either at discharge or around term equivalent age, and a few centres have access to a magnet in or adjacent to the neonatal intensive care unit and are doing sequential MRIs. In this review, we try to discuss when best to perform these two neuroimaging techniques and the additional information each technique may provide.     

High intensity focused ultrasound: surgery of the future?

For 50 years, high intensity focused ultrasound (HIFU) has been a subject of interest for medical research. HIFU causes selective tissue necrosis in a very well defined volume, at a variable distance from the transducer, through heating or cavitation. Over the past decade, the use of HIFU has been investigated in many clinical settings. This literature review aims to summarize recent advances made in the field. A Medline-based literature search (1965-2002) was conducted using the keywords "HIFU" and "high intensity focused ultrasound". Additional literature was obtained from original papers and published meeting abstracts. The most abundant clinical trial data comes from studies investigating its use in the treatment of prostatic disease, although early research looked at applications in neurosurgery. More recently horizons have been broadened, and the potential of HIFU as a non-invasive surgical tool has been demonstrated in many settings including the treatment of tumours of the liver, kidney, breast, bone, uterus and pancreas, as well as conduction defects in the heart, for surgical haemostasis, and the relief of chronic pain of malignant origin. Further clinical evaluation will follow, but recent technological development suggests that HIFU is likely to play a significant role in future surgical practice.     

Renal parenchymal diseases: is characterization feasible with ultrasound?

Ultrasound (US) imaging of the kidneys has greatly improved in recent years with introduction of wideband transducers and advances is beamformer technology. US is often the first imaging technique to be employed in patients with renal failure, haematuria or proteinuria, after clinical and laboratory evaluation. After conventional US evaluation, Doppler US (DUS) and resistive indices (RIs) analysis provide renal functional evaluation. Anyway, both sensitivity and specificity of conventional US and DUS in renal parenchymal disease evaluation remains low. In the initial or mild clinical stages of renal parenchymal diseases, kidneys may present normal US morphological appearance and normal RIs values, whereas different renal parenchymal diseases may reveal similar appearance on US and DUS evaluation. Besides, different renal parenchymal diseases may present some distinct features on conventional US and DUS with colour Doppler (CD) and power Doppler (PD) evaluation, even though percutaneous renal biopsy is often necessary to reach definite diagnosis. Renal vasculitides and tubular-interstitial nephropathies are more frequently identified by conventional US and DUS than glomerular nephropathies, since glomerular component accounts only for 8% of the renal parenchyma, whereas the highest percentage is occupied by vascular and tubulo-interstitial component. Follow-up of acute renal failure, during and after medical treatment, is the most useful field of employment of conventional US and DUS techniques, since a progressive lowering of RIs is correlated to a progressive recovery of renal function.     

Guided interventions in musculoskeletal ultrasound: what's the evidence?

Increasing histological and radiological understanding of the processes involved in soft-tissue injury is leading to novel targeted treatments. A number of reviews have recommended that these treatments should be performed with image guidance. This review describes current ultrasound-guided interventions and injections, together with the level of evidence for these. Discussion of guided interventions will include; percutaneous lavage (barbotage), brisement, dry needling, electrocoagulation, and of guided injections; corticosteroids, autologous substances (blood and platelet rich plasma), sclerosants, and prolotherapy (hyperosmolar dextrose). Representative imaging illustrating some of these techniques is included for correlation with the methods described. As these procedures are often performed in sportspeople, it is essential that the radiologist is aware of prohibited substances and methods outlined in an annual publication from the World Anti-Doping Association (WADA). Finally, future directions, including the use of autologous substances, mesenchymal and stem cells will be discussed.     

Musculoskeletal ultrasound and MRI: which do I choose?

In the diagnosis of musculoskeletal disorders, there are several applications where both ultrasound and magnetic resonance imaging (MRI) may be considered viable alternatives. Because there are advantages and disadvantages to each imaging method, often it is unclear which should be considered for a specific indication. This article reviews this topic in the following manner. First, musculoskeletal applications where there are significant advantages for the use of ultrasound are discussed, which includes evaluation of soft tissue foreign bodies, peripheral nerves, pathologies that require dynamic imaging for diagnosis, and soft tissues adjacent to metal hardware. This is followed by a discussion of indications where both ultrasound and MRI may be considered, such as evaluation of a focal tendon abnormality, focal ligament abnormality, soft tissue fluid collection, and confirmation of a probable benign cyst, such as Baker's cyst and wrist ganglion. Musculoskeletal ultrasound should be viewed as an imaging method that complements MRI rather than one that competes with MRI in the evaluation of musculoskeletal abnormalities, as it can offer important information.     

Which ultrasound transducer type is best for diagnosing pneumothorax?

Background

An accurate physical examination is essential in the care of critically ill and injured patients. However, to diagnose or exclude a pneumothorax, chest auscultation is unreliable compared to lung ultrasonography. In the dynamic prehospital environment, it is desirable to have the best possible ultrasound transducer readily available. The objective is to assess the difference between a linear-array, curved-array, and phased-array ultrasound transducer in the assessment for pneumothorax and to determine which is best.

Methods

In this double-blinded, cross-sectional, observational study, 15 observers, experienced in lung ultrasonography, each assessed 66 blinded ultrasound video clips of either normal ventilation or pneumothorax that were recorded with three types of ultrasound transducers. The clips were recorded in 11 adult patients that underwent thoracoscopic lung surgery immediately before and after the surgeon opened the thorax. The diagnostic accuracy of the three transducers, elapsed time until a diagnosis was made, and the perceived image quality was recorded.

Results

In total, 15 observers assessed 990 ultrasound video clips. The overall sensitivity and specificity were 98.2% and 97.2%, relatively. No significant difference was found in the diagnostic performance between transducers. A diagnosis was made slightly faster in the linear-array transducer clips, compared to the phased-array transducer (p?=?.031). For the linear-, curved-, and phased-array transducer, the image quality was rated at a median (interquartile range [IQR]) of 4 (IQR 3–4), 3 (IQR 2–4), and 2 (IQR 1–2), relatively. Between the transducers, the difference in image quality was significant (p?<?.0001).

Conclusions

There was no difference in diagnostic performance of the three transducers. Based on image quality, the linear-array transducer might be preferred for (prehospital) lung ultrasonography for the diagnosis of pneumothorax.