It has found use in protocols for whole-body venography [66] and was shown to produce images of comparable diagnostic quality but lower specificity compared with conventional MRV [67] in the assessment of central thoracic veins. It might eventually be used as a fast, noninvasive, and relatively safe imaging tool for screening and serial follow-up of patients with poor renal function, but further study is required [68]. Standard MRI sequences are always included in MRV protocols because they produce high-resolution images of the soft tissues surrounding the vessels and can help identify mimics of DVT and potential sources of extrinsic venous compression as well as signs of soft-tissue inflammation around the veins (edema on T2-weighted images and contrast enhancement on postcontrast T1-weighted sequences). MRV can be as effective as venography [46,62] but has limitations [33,45,50]. A meta-analysis found MRV to have both a high sensitivity and specificity [69], although the study did not focus on the upper extremities. CTV Upper Extremity CT can be used to assess the lumen of venous structures. It involves the injection of an iodinated contrast agent [34,38]. Delayed imaging at 90 to 120 seconds can permit evaluation of the central veins. CT can detect thrombi in vascular lumen or stenosis of the lumen. It has been used to assess the jugular veins [70,71], the brachiocephalic veins [72,73], and the superior vena cava [72]. Perivascular inflammatory changes around acute thrombi can also be detected by CT [74]. CT can be used to visualize external processes causing vascular compression or invasion, such as neoplastic processes [75]. CT is the main imaging modality for staging neoplastic involvement in the mediastinum and axillae, which can include vascular invasion or compression.
Suspected Upper Extremity Deep Vein Thrombosis. It has found use in protocols for whole-body venography [66] and was shown to produce images of comparable diagnostic quality but lower specificity compared with conventional MRV [67] in the assessment of central thoracic veins. It might eventually be used as a fast, noninvasive, and relatively safe imaging tool for screening and serial follow-up of patients with poor renal function, but further study is required [68]. Standard MRI sequences are always included in MRV protocols because they produce high-resolution images of the soft tissues surrounding the vessels and can help identify mimics of DVT and potential sources of extrinsic venous compression as well as signs of soft-tissue inflammation around the veins (edema on T2-weighted images and contrast enhancement on postcontrast T1-weighted sequences). MRV can be as effective as venography [46,62] but has limitations [33,45,50]. A meta-analysis found MRV to have both a high sensitivity and specificity [69], although the study did not focus on the upper extremities. CTV Upper Extremity CT can be used to assess the lumen of venous structures. It involves the injection of an iodinated contrast agent [34,38]. Delayed imaging at 90 to 120 seconds can permit evaluation of the central veins. CT can detect thrombi in vascular lumen or stenosis of the lumen. It has been used to assess the jugular veins [70,71], the brachiocephalic veins [72,73], and the superior vena cava [72]. Perivascular inflammatory changes around acute thrombi can also be detected by CT [74]. CT can be used to visualize external processes causing vascular compression or invasion, such as neoplastic processes [75]. CT is the main imaging modality for staging neoplastic involvement in the mediastinum and axillae, which can include vascular invasion or compression.