Approach to Venous Disease Terminology Venous anomaly Venous thrombosis Venous insufficiency Venous compression Venous aneurysms (varix) Venous malformations Anatomy-based Imaging Issues Imaging of venous diseases requires a thorough understanding of venous anatomy as well as the pathophysiology, clinical aspects, and therapeutic options of various venous diseases. With the advent of high-quality, cross-sectional imaging techniques, catheter-based venography is rarely performed for the diagnosis of venous disease, but it remains the best imaging technique to assess flow dynamics, collateral flow, intravascular pressure, and posttreatment effects. Extremity veins can be assessed adequately with US and color Doppler. The intrathoracic and intraabdominal veins are difficult to assess with US and often require the use of CT/MR venography for adequate visualization. Intravascular US is usually a part of catheter venography and is used to assess the intraluminal and mural abnormalities of the venous wall. Pathologic Issues Venous disorders can be grossly categorized into venoocclusive diseases, venous insufficiency (or valvular incompetence), venous aneurysms ((or varices), abnormal arteriovenous communications, venolymphatic malformations, and congenital anomalies. Pathology-based Imaging Issues Venoocclusive Diseases Venoocclusive diseases include acute and chronic deep venous thrombosis, venous webs, primary or secondary neoplastic invasion of the veins, and extrinsic venous compression. Acute venous thrombosis results in obliteration of the venous lumen with luminal thrombus, venous expansion, and perivenous edema. An acute thrombus is anechoic or hypoechoic on grayscale US and may be difficult to detect unless compression technique or color Doppler is used. Acutely thrombosed veins are noncompressible. Color flow imaging shows absence of flow in the thrombosed vein. CT venography demonstrates a filling defect within the thrombosed vein, and the vein wall may enhance in a rim-like fashion with perivenous stranding. Both noncontrast MR venography and contrast-enhanced MR venography are helpful in detecting acute venous thrombosis. The findings are similar to those of CT venography. T2-weighted images are helpful in assessing perivenous inflammation. Chronic deep venous thrombosis results in scarring of the vein with complete occlusion or partial recanalization of the vein. US demonstrates a partially compressible, small-caliber vein with multiple flow channels within the lumen. CT/MR venography are very helpful in detecting the collateral veins in the setting of chronic venous thrombosis. Intravenous tumor extension or primary venous tumor (such as leiomyomatosis) appears similar to that of acute deep venous thrombosis (intraluminal filling defect on CT/MR venography and noncompressible vein on US); however, contrast-enhanced studies demonstrate enhancement of the intravenous tumor that is not observed in bland (nontumor) thrombus. Extrinsic venous compression can be easily recognized on CT/MR venography. Venous webs are usually congenital; however, acquired webs can result from chronic deep venous thrombosis and extrinsic venous compression. Congenital webs occur in large veins, such as the inferior vena cava (IVC) and hepatic veins, and are best observed on US, high-resolution double inversion-recovery T1-weighted MR, catheter venography, and intravascular US. The webs appear as thin, transverse, linear soft tissue structures and, depending on the severity of obstruction, there may be venous dilation or collateral formation peripheral to the obstruction. Acquired webs are usually multiple and of varied thickness and may be seen on imaging as discrete webs. Calcifications, commonly observed with chronic deep vein thrombosis, are well seen on CT. Acquired webs are best visualized on intravascular US, but catheter venography may be able to detect flow limiting webs, especially when there is flow between the webs. Extrinsic venous compression can occur from normal or abnormal adjacent arteries, muscles, and bones or from pathological structures, such as tumors and enlarged lymph nodes. CT and MR are helpful in detecting pathological causes of venous compression. Dynamic extrinsic compression of the veins by bones or ligaments (as seen in thoracic outlet syndrome and popliteal venous compression) can be assessed on color Doppler and MR/CT venography; however, it is best appreciated on dynamic catheter venography. Color Doppler evaluation of the peripheral veins may allow detection of secondary effects of central venous occlusion by demonstrating absence of respiratory phasicity in the venous flow. Extrinsic venous compression may also lead to development of collateral veins depending on the severity of obstruction, peripheral venous thrombosis, and peripheral venous valvular insufficiency. Chronic repetitive compression of the veins by arteries (as seen in May-Thurner syndrome) may lead to chronic endothelial injury, mural spurs, and chronic webs and occlusion. Catheter venography and intravascular US are the most useful imaging tests to assess such extrinsic arterial compression. Time-of-flight sequences of MR venography aimed at imaging venous flow may also be helpful in the assessment of the hemodynamic significance of such extrinsic venous compression through detection of flow reversal or collateral flow. Following endovascular therapy, venous flow assessment can be performed with color Doppler, CT/MR venography, and catheter angiography. MR venography is not useful in assessing patency of venous stents. Venous Insufficiency Venous insufficiency results from the failure of valvular function that occurs as a result of primary venous wall/valve disease or secondary to chronic deep venous thrombosis or chronic venous hypertension from a central venous obstruction. Chronic venous insufficiency of the lower extremities may lead to varicose veins in the legs, pedal edema, dermatitis related to chronic venous stasis, lipodermosclerosis, and venous ulcerations. Patients usually present with cosmetic embarrassment from varicose veins, leg pain, fatigue, heaviness or discomfort, leg swelling, skin discoloration, or ulcer. Imaging allows accurate identification of the location and severity of valvular incompetence. Color Doppler evaluation is the best imaging test to assess venous insufficiency of the extremities. Valve closure times are assessed during a stress maneuver (e.g., Valsalva or squeeze-release technique). The normal valve closure times are as follows: 0.5 second for saphenous veins and 1.0 second for deep veins. Chronic venous insufficiency affecting the perforator veins is often difficult to assess, but dilated (> 3.5 mm in diameter) perforator veins are usually considered abnormal. MR/CT venography have shown promise in detecting dilated perforator veins. Chronic venous insufficiency may also affect the gonadal veins leading to varicocele in men and pelvic varices in women. These could be detected on multiphase contrast-enhanced MR/CT venography and catheter venography. Only gold members can continue reading. 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Approach to Venous Disease Terminology Venous anomaly Venous thrombosis Venous insufficiency Venous compression Venous aneurysms (varix) Venous malformations Anatomy-based Imaging Issues Imaging of venous diseases requires a thorough understanding of venous anatomy as well as the pathophysiology, clinical aspects, and therapeutic options of various venous diseases. With the advent of high-quality, cross-sectional imaging techniques, catheter-based venography is rarely performed for the diagnosis of venous disease, but it remains the best imaging technique to assess flow dynamics, collateral flow, intravascular pressure, and posttreatment effects. Extremity veins can be assessed adequately with US and color Doppler. The intrathoracic and intraabdominal veins are difficult to assess with US and often require the use of CT/MR venography for adequate visualization. Intravascular US is usually a part of catheter venography and is used to assess the intraluminal and mural abnormalities of the venous wall. Pathologic Issues Venous disorders can be grossly categorized into venoocclusive diseases, venous insufficiency (or valvular incompetence), venous aneurysms ((or varices), abnormal arteriovenous communications, venolymphatic malformations, and congenital anomalies. Pathology-based Imaging Issues Venoocclusive Diseases Venoocclusive diseases include acute and chronic deep venous thrombosis, venous webs, primary or secondary neoplastic invasion of the veins, and extrinsic venous compression. Acute venous thrombosis results in obliteration of the venous lumen with luminal thrombus, venous expansion, and perivenous edema. An acute thrombus is anechoic or hypoechoic on grayscale US and may be difficult to detect unless compression technique or color Doppler is used. Acutely thrombosed veins are noncompressible. Color flow imaging shows absence of flow in the thrombosed vein. CT venography demonstrates a filling defect within the thrombosed vein, and the vein wall may enhance in a rim-like fashion with perivenous stranding. Both noncontrast MR venography and contrast-enhanced MR venography are helpful in detecting acute venous thrombosis. The findings are similar to those of CT venography. T2-weighted images are helpful in assessing perivenous inflammation. Chronic deep venous thrombosis results in scarring of the vein with complete occlusion or partial recanalization of the vein. US demonstrates a partially compressible, small-caliber vein with multiple flow channels within the lumen. CT/MR venography are very helpful in detecting the collateral veins in the setting of chronic venous thrombosis. Intravenous tumor extension or primary venous tumor (such as leiomyomatosis) appears similar to that of acute deep venous thrombosis (intraluminal filling defect on CT/MR venography and noncompressible vein on US); however, contrast-enhanced studies demonstrate enhancement of the intravenous tumor that is not observed in bland (nontumor) thrombus. Extrinsic venous compression can be easily recognized on CT/MR venography. Venous webs are usually congenital; however, acquired webs can result from chronic deep venous thrombosis and extrinsic venous compression. Congenital webs occur in large veins, such as the inferior vena cava (IVC) and hepatic veins, and are best observed on US, high-resolution double inversion-recovery T1-weighted MR, catheter venography, and intravascular US. The webs appear as thin, transverse, linear soft tissue structures and, depending on the severity of obstruction, there may be venous dilation or collateral formation peripheral to the obstruction. Acquired webs are usually multiple and of varied thickness and may be seen on imaging as discrete webs. Calcifications, commonly observed with chronic deep vein thrombosis, are well seen on CT. Acquired webs are best visualized on intravascular US, but catheter venography may be able to detect flow limiting webs, especially when there is flow between the webs. Extrinsic venous compression can occur from normal or abnormal adjacent arteries, muscles, and bones or from pathological structures, such as tumors and enlarged lymph nodes. CT and MR are helpful in detecting pathological causes of venous compression. Dynamic extrinsic compression of the veins by bones or ligaments (as seen in thoracic outlet syndrome and popliteal venous compression) can be assessed on color Doppler and MR/CT venography; however, it is best appreciated on dynamic catheter venography. Color Doppler evaluation of the peripheral veins may allow detection of secondary effects of central venous occlusion by demonstrating absence of respiratory phasicity in the venous flow. Extrinsic venous compression may also lead to development of collateral veins depending on the severity of obstruction, peripheral venous thrombosis, and peripheral venous valvular insufficiency. Chronic repetitive compression of the veins by arteries (as seen in May-Thurner syndrome) may lead to chronic endothelial injury, mural spurs, and chronic webs and occlusion. Catheter venography and intravascular US are the most useful imaging tests to assess such extrinsic arterial compression. Time-of-flight sequences of MR venography aimed at imaging venous flow may also be helpful in the assessment of the hemodynamic significance of such extrinsic venous compression through detection of flow reversal or collateral flow. Following endovascular therapy, venous flow assessment can be performed with color Doppler, CT/MR venography, and catheter angiography. MR venography is not useful in assessing patency of venous stents. Venous Insufficiency Venous insufficiency results from the failure of valvular function that occurs as a result of primary venous wall/valve disease or secondary to chronic deep venous thrombosis or chronic venous hypertension from a central venous obstruction. Chronic venous insufficiency of the lower extremities may lead to varicose veins in the legs, pedal edema, dermatitis related to chronic venous stasis, lipodermosclerosis, and venous ulcerations. Patients usually present with cosmetic embarrassment from varicose veins, leg pain, fatigue, heaviness or discomfort, leg swelling, skin discoloration, or ulcer. Imaging allows accurate identification of the location and severity of valvular incompetence. Color Doppler evaluation is the best imaging test to assess venous insufficiency of the extremities. Valve closure times are assessed during a stress maneuver (e.g., Valsalva or squeeze-release technique). The normal valve closure times are as follows: 0.5 second for saphenous veins and 1.0 second for deep veins. Chronic venous insufficiency affecting the perforator veins is often difficult to assess, but dilated (> 3.5 mm in diameter) perforator veins are usually considered abnormal. MR/CT venography have shown promise in detecting dilated perforator veins. Chronic venous insufficiency may also affect the gonadal veins leading to varicocele in men and pelvic varices in women. These could be detected on multiphase contrast-enhanced MR/CT venography and catheter venography. Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related posts: page 2: CORONARY ARTERY DISEASE 7: CONGENITAL HEART DISEASE INDEX Multimodality Approach to Cardiovascular Disorders Approach to Heart Failure Stay updated, free articles. Join our Telegram channel Join Tags: CT and MR in Cardiology Apr 6, 2020 | Posted by admin in CARDIOVASCULAR IMAGING | Comments Off on Approach to Venous Disease Full access? Get Clinical Tree
