Ultrasonography probes used for pleural ultrasonography

(A) Phased array probe (1-5 MHz frequency): This probe is used for general thoracic ultrasonography. It has a small footprint, so it is well adapted to scan between rib interspaces. As compared with the higher frequency linear probe, it has superior penetration but inferior resolution capability. It is also standard probe design for echocardiography.
(B) Linear array probe (5-10 MHz frequency): This probe is used for detailed examination of pleural line anatomy and to identify vascular structures that would contraindicate needle insertion for thoracentesis. As compared with the lower frequency phased array probe, it has superior resolution but inferior penetration capability. It is standard probe design for guidance of vascular access.