Real-time elastography is a method for visualization of the elastic properties of soft tissue and may potentially enable differentiation between malignant and benign pathologic lesions. Our aim was to validate the method on a tissue-mimicking (TM) phantom and to evaluate the influence of different scanning parameters and investigator variability. A TM-phantom containing eight spherical inclusions with known storage modulus was examined using two different transducers on an ultrasound (US) scanner equipped with software for real-time elasticity imaging. The ultrasound transducers were moved vertically in a repetitive manner to induce strain. Two investigators performed series of standardized elastography scans applying a 0-4 categorical quality scale to evaluate the influence of seven parameters: dynamic range of elasticity, region-of-interest, frequency of transducer movement, rejection of elastogram noise, frame rate, persistence and smoothing. Subsequently, repeated examinations of four selected inclusions were performed using a visual analog scale (VAS) where investigators marked a 100 mm horizontal line representing the span in image quality based on experience from the first examination. The hardest and softest inclusions were imaged more clearly than the inclusions with elasticity more similar to the background material. Intraobserver agreement on elastogram quality was good (kappa: 0.67 - 0.75) and interobserver agreement average (kappa: 0.55 - 0.56) when using the categorical scale. The subsequent VAS evaluation gave intraclass-correlation coefficients for the two observers of 0.98 and 0.93, respectively, and an interclass-correlation coefficient of 0.93. Real-time elastography adequately visualized isoechoic inclusions with different elastic properties in a TM-phantom with acceptable intra- and interobserver agreement. Dynamic range of elasticity was the parameter with most impact on the elastographic visualization of inclusions.

Choice of treatment can be challenging in the casualty clinic. Early in the disease course in particular, clinical signs can be sparse and diagnostic tools limited. Sometimes the road to ruin is paved with good intentions. Symptoms of a respiratory tract infection are among the most common reasons for attendance at GP surgeries and casualty clinics. In the current case, a viral upper respiratory tract infection is a likely diagnosis, while infection-triggered obstructive pulmonary disease, pneumonia and influenza are possible differential diagnoses. It was not influenza season, but there was an ongoing mycoplasma epidemic. Symptoms of atypical pneumonia are a long-lasting severe dry cough, sore throat and headache, but the patient had neither a cough nor a sore throat. A boy in his earlyRarer differential diagnoses were considered unlikely. He had a low risk of pulmonary embolism and no stabbing pains upon inspiration. The absence of pain also made pneumothorax and pleuritis unlikely. In addition, he had similar respiratory sounds on both sides. With tuberculosis we would have expected a cough, which he did not have. He had no heart problems and there was no suspicion of heart failure. Bronchitis and pneumonia are frequent causes of shortness of breath. Bronchitis is chiefly attributable to viruses, while pneumonia in adults is usually caused by bacteria. The most common agents outside hospitals are Streptococcus pneumoniae, followed by Chlamydophila pneumoniae and viruses, as well as M. pneumoniae during epidemics every few years. In children over three months, the aetiology is reversed, with viruses the most common agents. Bacteria are the main cause in the very young.