| Mügge, 1991(7) | Technical note | Cardiology, Neurology | 56 (Adults) | Syringomielia (5), Neurofibromatosis (1) | Hewlett Packard, Acuson; 5 Mhz | Upper thoracic and lower cervical (100% 2 segments; 75% 3–5 segments; 25% >5 segments) | 30 cm from the incisors (aortic valve/left atrial appendage), descending aorta, 20–30° left rotation | Yes (homogeneous, hypoechoic, central canal/central echo) | Yes (anechoic) | - | Pia mater (thin, hyperechoic) | - | - | - | - | In syringomyelia, intramedullary cavities with no central echo; in neurofibromatosis, masses abutting the spinal cord |
| Godet, 1994(8) | Prospective observational study | Vascular surgery | 17 (Adults) | None | Hewlett Packard; 5 Mhz | Cervical/Thoracic (min C5–6; max T10–11) | CXR | Yes (pulsation) | - | - | - | - | - | - | Probe distance from incisors: 20 cm = T1–T2; 38 cm = T10–11; 2–3 cm per interspace | Cord not visualized below T10–T11; artery of Adamkiewicz not identified |
| Voci, 1999(9) | Case report | Cardiac surgery | 1 (Adult) | None | Acuson, Sequoia C–256; 5–7 MHz; Nyquist limit 0.039 m/s | Thoracic and Cervical | First supradiaphragmatic vertebral body (T12) | Yes | Yes | - | - | Anterior spinal artery, radicular branches, intercostal arteries | Successful | ASA Vmax = 14 cm/s | Anterior spinal artery (ASA) Vmax = 14 cm/s | Absence of the anterior spinal artery (T6–T8) indicates a watershed area |
| Orihashi, 2006(10) | Prospective observational study | Cardiac surgery/Trauma surgery | 22 (Adults) | tSAH (3) | Hitachi, EUB–555; Aloka, SSD 5500; 5 Mhz | Upper thoracic | 20–30 cm from the incisors | Yes | Yes | - | Pia mater | - | - | - | Cord-to-canal ratio: tSAH 0.59±0.07 vs controls 0.45±0.04; meningeal thickness: 1.41±0.12 mm vs 0.66±0.15 mm | In traumatic subarachnoid hemorrhage (tSAH), fibrin-like echogenic images within the subarachnoid space, meningeal thickening >1 mm, increased cord-to-canal ratio >0.5; changes detectable as early as 3.5 h after injury |
| Chitilian, 2006(11) | Case report | Cardiac surgery | 1 (Adult) | None | - | Thoracic (level not specified) | - | Yes (pulsation) | - | - | Dura mater | - | - | - | - | - |
| Lohser, 2009(12) | Case report | Cardiac surgery | 1 (Adult) | None | General Electric, Vivid 7 | Thoracic (level not specified) | Descending aorta, left rotation | Yes (pulsation) | Yes | Yes | - | - | - | - | - | - |
| Nath, 2011(13) | Case report | Cardiac surgery | 1 (Adult) | None | Philips, Agilent SONOS-5500 | Thoracic (level not specified) | - | Yes (pulsation) | Yes | Yes | - | - | Unsuccessful | - | - | - |
| Ueda, 2013(14) | Case report | Cardiac surgery | 12 (Pediatric 16 days – 4 years) | None | Philips, T6207 | Thoracic (level not specified) | Descending aorta, 10–20° left rotation; tracheal carina (T5/T6); esophagogastric junction (T11) | Yes | - | Yes | Dura mater | Anterior and posterior spinal arteries | - | - | Spread of anesthetic/saline in the epidural space | Epidural catheter |
| Ahmed, 2014(15) | Case report | Interventional cardiology/TEER | 1 (Adult) | None | Philips, iE 33, X7-2t (3D xMATRIX) | Lower cervical/Upper thoracic | Ascending aorta; aortic arch | Yes | Yes | - | - | Anterior spinal arteries | - | - | Cord volume 0.64 mL; dimensions 1.49×0.82×0.70 cm; area 1.05 cm2; canal: volume 1.90 mL; dimensions 1.71×1.20×1.12 cm; area 1.76 cm2; anterior spinal arteries (left Ø 0.26 cm, right Ø 0.31 cm) | - |
| Feinglass, 2015(16) | Retrospective study | Cardiothoracic surgery | 2 (Adults) | None | Philips, IE-33, X7-2t (3D xMATRIX) | Thoracic (T4–T12) | Mid-esophageal to transgastric projection | Yes | Yes | Yes | - | Anterior spinal arteries (biphasic flow) | Unsuccessful | V = 9.74 cm/s | - | Epidural catheter |
| Goswami, 2016(17) | Prospective observational study | Thoracic surgery | 24 (Adults) | None | Philips, S7 (pediatric) | Thoracic | Four-chamber view; descending aorta (T4) | Yes | Yes | - | Dura mater; epidural space | - | - |
| Catheter position: posterior 83%, lateral 17%; poorer anesthetic quality with lateral position | Epidural catheter – tip location: T4 (4%), T5 (79%), T6 (17%) |
| Hanada, 2023(18) | Prospective observational study and Case series | Surgery/Pediatrics | 94 (Pediatric 2 days – 17 years/Adult) | None | Philips IE33 (iE33); X7-2t (3D xMATRIX); S7-3t (pediatric); S8-3t (TEE) | Thoracic (T1–T12) | Pulmonary artery bifurcation (T5–T6); IVC/esophagus traversing the diaphragm (T11–T12); CXR | Yes | Yes | - | Dura mater; epidural space | - | - |
| Segments visualized: 99% in children vs 70% in adults; catheter confirmation: TEE 19/19 vs ultrasound 8/19 | Epidural catheter; markedly better TEE visualization in children |
| Kisling, 2023(19) | Case report | Cardiac surgery | 1 (Adult) | None | - | Upper thoracic | - | Yes (pulsation) | - | Yes | Dura mater; epidural space | - | - |
| - | Disc structures (annulus fibrosus, nucleus pulposus); vertebral structures (spinous process, lamina, costovertebral facet) |
