Table 2.

Technical aspect and characteristics of ultrasound machines.

Reference	US Mode	Transducer, and Technical Specifications	No. Sites Evaluated	Scanning Protocol and Position of the Patient	US Image Reader Blinded
Gutierrez¹⁴	GS	Convex probe, MyLab 70 XVG (Esaote S.p.A.), 2–7 MHz	50 and 14	Standardized technique. Patient positions were supine or near-supine for the anterior chest scanning, while in a sitting position for the posterior chest scanning.	Yes
Aghdashi¹⁹	GS	Linear probe, Siemens sonoline G-40 (Siemens), 7–10 MHz	10	Standardized technique. Patients were examined in supine position for assessment of anterior chest wall and in sitting position for assessment of posterior chest wall.	NR
Barskova²⁰	GS	Cardiac sector transducer 2.5 cm in length (Mylab50, Esaote), 2.5–3.5 MHz	72	Standardized technique. Patients in the supine position for anterior and lateral scanning, and in the sitting position for dorsal scanning.	No
Buda²¹	GS	Linear probe 8–11MHz, convex probe 3.5–5MHz, Logiq 7 system (GE Healthcare)	NR	Standardized technique. Patients remaining in the sitting and supine position.	NR
Gargani¹¹	GS	Convex probe, cardiac sector transducer (2.5 cm long), Mylab25 (Esaote), 2.5–3.5 MHz	NR	Standardized technique. Patients in the supine or near-supine position for the anterior scanning, and in the sitting position for the dorsal scanning.	Yes
Gigante²²	GS	Convex probe, Toshiba Ultrasound System, 2.5 to 3.5 MHz	NR	Standardized technique. Position of patients NR.	No
Moazedi-Fuerst²³	GS	Convex probe 3.5 MHz, linear probe NR	NR	Standardized technique. The anterior pleural surface was investigated in a supine position while the lateral and posterior surfaces were scanned in a sitting position.	NR
Pinal-Fernandez²⁴	GS	Linear probe. MyLabTwice system, 5 MHz	72	Standardized technique. Patients in supine position to record the anterior and anterolateral sonographic points and in sitting position for the posterior and posterolateral ones.	NR
Sperandeo¹²	GS	Convex probe, 3.5–5 MHz	NR	Protocol and patient position NR.	NR
Tardella¹³	GS	Convex probe, MyLab 70 XVG (Esaote Biomedica) equipped 2–7 MHz	50	Patients in the supine or near-supine position (with the arms elevated and hands clasped behind the neck) for anterior and lateral scanning, and in the sitting position (with the arms along the trunk) for posterior scanning.	Yes
Moazedi-Fuerst¹⁰	GS	Convex probe and linear probe, 3.5 MHz	18	Standardized technique. The anterior pleural surface was investigated in a supine position while the lateral and posterior surface was scanned in a sitting position.	NR
Mohammadi²⁵	GS	Linear probe, Medison Accuvix V20, 7–10 MHz	10	Standardized technique. Patients were examined in supine position for assessment of anterior chest wall and in sitting position for the posterior chest wall.	NR

US: ultrasound; GS: greyscale; NR: not registered.