Chest wall – underappreciated structure in sonography. Part I: Examination methodology and ultrasound anatomy

Abstract

Chest wall ultrasound has been awarded little interest in the literature, with chest wall anatomy described only in limited extent. The objective of this study has been to discuss the methodology of chest wall ultrasound and the sonographic anatomy of the region to facilitate professional evaluation of this complex structure. The primarily used transducer is a 7–12 MHz linear one. A 3–5 MHz convex (curvilinear) transducer may also be helpful, especially in obese and very muscular patients. Doppler and panoramic imaging options are essential. The indications for chest wall ultrasound include localized pain or lesions found or suspected on imaging with other modalities (conventional radiography, CT, MR or scintigraphy). The investigated pathological condition should be scanned in at least two planes. Sometimes, evaluation during deep breathing permits identification of pathological mobility (e.g. in rib or sternum fractures, slipping rib syndrome). Several structures, closely associated with each other, need to be considered in the evaluation of the chest wall. The skin, which forms a hyperechoic covering, requires a high frequency transducer (20–45 MHz). The subcutaneous fat is characterized by clusters of hypoechoic lobules. Chest muscles have a very complex structure, but their appearance on ultrasound does not differ from the images of muscles located in other anatomical regions. As far as cartilaginous and bony structures of the chest are concerned, the differences in the anatomy of the ribs, sternum, scapula and sternoclavicular joints have been discussed. The rich vascular network which is only fragmentarily accessible for ultrasound assessment has been briefly discussed. A comprehensive evaluation of the chest wall should include the axillary, supraclavicular, apical and parasternal lymph nodes. Their examination requires the use of elastography and contrast-enhanced ultrasound.

Breast ultrasound: An opportunity to detect unsuspected pleural and pulmonary abnormalities

“…The eyes of the US operator performing a breast examination point with the maximum care toward the central part of the field of view, that is, toward the mammary gland and its abnormalities. However, it is not so rare to identify, we may say “with the corner of the eye,” changes located in the more superficial layer, that is, the skin and subcutaneous tissue, or changes within the deeper layer, that is, the pectoralis muscle, the ribs, intercostal space, pleural line, and uppermost portion of the lung 28,29 …”

“…However, it is not so rare to identify, we may say "with the corner of the eye," changes located in the more superficial layer, that is, the skin and subcutaneous tissue, or changes within the deeper layer, that is, the pectoralis muscle, the ribs, intercostal space, pleural line, and uppermost portion of the lung. 28,29 Technically, all the apparatuses used for sonographic investigation of breast may also be used to examine the thorax. A high-resolution linear transducer as the one routinely used in breast sonography, working at frequencies between 10 and 15 MHz, is suitable for imaging the thorax wall, pleura, and the surface of the lung.…”

Mixed Imaging Sequences for Improved Spatiotemporal Resolution in Cardiac Imaging

“…In addition to exhibiting significant tissue motion, the heart is also located in an acoustically challenging environment. The ribs, which are comprised of compact bone, almost completely attenuate the propagation of an ultrasound beam [31]. Thus, imaging between the ribs is a necessity.…”