This corresponds to the definitions that the CMS has applied to the Current Procedural Terminology codes. CT venography (CTV) is obtained separately for each arm position 120 to 180 seconds after IV injection of iodinated contrast [6] in order to obtain venous opacification. The contrast injection should be performed in either the contralateral arm or other location. Multiplanar reformations are then produced to evaluate the thoracic space and true axial compression of the vessel. Center-line and volume-rendered images may also be produced to aid in visualization. CTA chest and CTV chest specifically denote studies tailored to evaluating the chest and thoracic outlet. These include evaluation of central vessels as well as subclavian and axillary arteries and veins, respectively. This is distinct from CTA upper extremity and CTV upper-extremity protocols, which are designed to evaluate the entire limb peripherally to the level of the wrist. Contrast-enhanced 3-D MR angiography (MRA) techniques have been described at both 1.5T and 3T to assess for TOS [19]. Breath-hold arterial phase contrast-enhanced 3-D MRA and equilibrium phase imaging is obtained using a 3-D gradient-echo pulse sequence with fat suppression. These can be obtained in both neutral and stressed positions with the exact protocol customized to institutional needs. A coronal oblique 3-D slab of the MRA is often obtained covering bilateral subclavian and axillary vessels. Unenhanced mask imaging is followed by multiphase contrast-enhanced dynamic acquisition in the same orientation. Noncontrast time-of-flight MRA may be considered, particularly in patients with contraindications to gadolinium-based contrast; however, these techniques suffer from flow artifacts, which could lead to false diagnosis of stenosis or thrombosis [19]. Noncontrast MRA Thoracic Outlet Syndrome also requires long acquisition times when combined with postural maneuvers that may be difficult to achieve for patients with severe clinical symptoms.
Thoracic Outlet Syndrome. This corresponds to the definitions that the CMS has applied to the Current Procedural Terminology codes. CT venography (CTV) is obtained separately for each arm position 120 to 180 seconds after IV injection of iodinated contrast [6] in order to obtain venous opacification. The contrast injection should be performed in either the contralateral arm or other location. Multiplanar reformations are then produced to evaluate the thoracic space and true axial compression of the vessel. Center-line and volume-rendered images may also be produced to aid in visualization. CTA chest and CTV chest specifically denote studies tailored to evaluating the chest and thoracic outlet. These include evaluation of central vessels as well as subclavian and axillary arteries and veins, respectively. This is distinct from CTA upper extremity and CTV upper-extremity protocols, which are designed to evaluate the entire limb peripherally to the level of the wrist. Contrast-enhanced 3-D MR angiography (MRA) techniques have been described at both 1.5T and 3T to assess for TOS [19]. Breath-hold arterial phase contrast-enhanced 3-D MRA and equilibrium phase imaging is obtained using a 3-D gradient-echo pulse sequence with fat suppression. These can be obtained in both neutral and stressed positions with the exact protocol customized to institutional needs. A coronal oblique 3-D slab of the MRA is often obtained covering bilateral subclavian and axillary vessels. Unenhanced mask imaging is followed by multiphase contrast-enhanced dynamic acquisition in the same orientation. Noncontrast time-of-flight MRA may be considered, particularly in patients with contraindications to gadolinium-based contrast; however, these techniques suffer from flow artifacts, which could lead to false diagnosis of stenosis or thrombosis [19]. Noncontrast MRA Thoracic Outlet Syndrome also requires long acquisition times when combined with postural maneuvers that may be difficult to achieve for patients with severe clinical symptoms.