No large series of studies have looked at the diagnostic accuracy of this technique for diagnosing upper-extremity venous thrombosis, although extensive experience is accumulating with lower-extremity venous thrombosis. One small series showed that the performance of CT venography (CTV) is similar to that of conventional venography in the thoracic and upper- extremity veins and it evaluates the central extent of obstruction more effectively [75]. Nuclear Medicine Venography Upper Extremity Radionuclide venography involves the peripheral injection of radiopharmaceuticals or labeled small particles (eg, macroaggregated albumin, red blood cells, albumin, platelets) to assess drainage of extremities via the veins or lymphatics, or to directly detect the presence of thrombus (eg, platelets or specific markers). Patent vessels will take up the radiopharmaceuticals, whereas obstructed vessels will not. Failure to visualize specific veins, combined with 4 Suspected Upper-Extremity Deep Vein Thrombosis visualization of collateral veins, indicate either venous thrombosis or external compression of venous segments [2,25,26,28]. Radionuclide venography has been considered the reference standard for lymphedema [77]. For edema related to lymphatic obstruction, the presence of certain features, such as dermal backflow and lymph node asymmetry, can increase the diagnostic specificity after intradermal injection [78]. Some authors have indicated that differentiating between primary lymphedema and secondary lymphedema, such as that due to venous obstruction, may be limited when using intradermal lymphangiography alone [79]. MR lymphangiography is currently being evaluated as an alternative to conventional, radionuclide lymphoscintigraphy and may play a larger role in the future [80,81]. Radiography Chest Although chest radiography cannot assess vascular patency, it can identify factors that can cause external compression or invasion of vessels, such as cervical rib or a mass lesion.
Suspected Upper Extremity Deep Vein Thrombosis. No large series of studies have looked at the diagnostic accuracy of this technique for diagnosing upper-extremity venous thrombosis, although extensive experience is accumulating with lower-extremity venous thrombosis. One small series showed that the performance of CT venography (CTV) is similar to that of conventional venography in the thoracic and upper- extremity veins and it evaluates the central extent of obstruction more effectively [75]. Nuclear Medicine Venography Upper Extremity Radionuclide venography involves the peripheral injection of radiopharmaceuticals or labeled small particles (eg, macroaggregated albumin, red blood cells, albumin, platelets) to assess drainage of extremities via the veins or lymphatics, or to directly detect the presence of thrombus (eg, platelets or specific markers). Patent vessels will take up the radiopharmaceuticals, whereas obstructed vessels will not. Failure to visualize specific veins, combined with 4 Suspected Upper-Extremity Deep Vein Thrombosis visualization of collateral veins, indicate either venous thrombosis or external compression of venous segments [2,25,26,28]. Radionuclide venography has been considered the reference standard for lymphedema [77]. For edema related to lymphatic obstruction, the presence of certain features, such as dermal backflow and lymph node asymmetry, can increase the diagnostic specificity after intradermal injection [78]. Some authors have indicated that differentiating between primary lymphedema and secondary lymphedema, such as that due to venous obstruction, may be limited when using intradermal lymphangiography alone [79]. MR lymphangiography is currently being evaluated as an alternative to conventional, radionuclide lymphoscintigraphy and may play a larger role in the future [80,81]. Radiography Chest Although chest radiography cannot assess vascular patency, it can identify factors that can cause external compression or invasion of vessels, such as cervical rib or a mass lesion.