Todd Taylor

Tendon Evaluation With Ultrasonography

T he vast majority of musculotendinous injuries occur secondary to violent contraction or excessive stretching.1 Ligamentous injuries, on the other hand, are due to an abnormal motion of joints. The magnitude of inciting forces results in a spectrum of pathology, ranging from a minor tear to a complete disruption of structures. Ultrasonography provides a detailed assessment of soft tissue anatomy and dynamic functionality, and in some instances can be comparable or even superior to magnetic resonance imaging2 because the structural characteristics of certain tendons make them ideal for imaging via ultrasonography. We describe some of these characteristics and highlight their utility in diagnostic imaging.

Ultrasound guided chest tube placement for basilar pneumothorax.

A 52-year-old woman with a history of COPD presented to the emergency department with severe shortness of breath. She reported 1 week of mild dyspnea, productive cough, and subjective fevers. Her shortness of breath acutely worsened just prior to presentation. She had suffered numerous prior spontaneous pneumothoraces, which had been treated with tube thoracostomies and chemical and mechanical pleurodesis. Her initial vital signs were heart rate 131 beats/min, respiratory rate 30 breaths/min, blood pressure 138/106 torr, oxygen saturation 100 % on nonrebreather mask, and temperature 36.9 C. The physical examination revealed moderate respiratory distress with diffuse wheezing on the right and decreased breath sounds at the left base. On inspection of the chest, there was extensive scarring of the left chest wall from previous procedures. A portable chest X-ray study showed a moderate-sized, primarily basilar pneumothorax with adhesions to the chest wall (Fig. 1). The patient developed worsening respiratory distress with an increase in heart rate to 160 beats/min and a respiratory rate of 50 breaths/min. Her blood pressure was unchanged. The decision was made by providers to perform an emergent tube thoracostomy due to concern for impending respiratory failure. Given the basilar location of her pneumothorax, traditional landmark guided location for chest tube placement was felt to pose a high risk of lung injury. Instead, ultrasound was used to locate the pneumothorax, inflated lung, and the diaphragm to determine the optimal site for chest tube placement. A point-of-care ultrasound examination was performed by the treating emergency physicians using a 12to 4-MHz linear array transducer (Philips Sparq, Andover MA, USA). The probe was initially placed in the midaxillary line over approximately the 5th intercostal space at the site of traditional landmark guided chest tube placement. At this location, inflated lung was identified by the presence of comet tail artifacts, and confirmed with M-mode (Fig. 2). The ultrasound probe was then moved inferiorly, and each rib space was evaluated until the ‘‘lung point’’ was found. The ‘‘lung point’’ is the ultrasound finding that identifies the interface of normal lung as it transitions to pneumothorax. In this location, inflated lung is seen sliding in and out of a rib space. The probe was then moved further inferiorly until only a pneumothorax pattern was seen (Fig. 3). We then moved further inferiorly to ensure that we were at an adequate distance from the diaphragm to proceed. Once the site was identified, we prepared for chest tube insertion. The probe and patient were prepped and draped in normal sterile fashion. Next, the probe was placed at the chosen insertion site so that the ribs inferior and superior to the insertion point were visualized. A finder needle was inserted under in-plane ultrasound guidance so that the needle could be visualized passing over the superior edge of the inferior rib into the chest cavity. Air was aspirated, and a small-bore chest tube was placed using traditional Seldinger technique. Upon connection to suction, the patient experienced immediate improvement in her respiratory distress. Repeat chest & Sierra Beck sierra.c.beck@emory.edu

Tips and Tricks for Imaging Digits

C linicians familiar with point-of-care (POC) ultrasound know that structures such as the hands and feet require the use of the linear high-frequency transducer to obtain quality images. In reality, however, employing the standard technique (ie, applying gel to the probe surface and scanning the structure) can be challenging due to the uneven surfaces of the fingers and toes; therefore, obtaining good contact with the transducer is harder than it may seem at first glance. Additionally, since these structures are superficial, they are usually seen on the top half of the ultrasound display, while the focal zone of most ultrasound machines is located in the middle of the display and is nonadjustable. We describe two simple adjuncts to POC ultrasound that can assist in visualizing digital structures with greater ease and improved image resolution: the water bath1,2 and standoff pad techniques.