Collateral pathways in superior vena caval obstruction as seen on CT

Paradoxical Cerebral Embolism Secondary to Superior Vena Cava Occlusion and Development of a Systemic Right-to-Left Shunt

Paradoxical cerebral embolism, although rare, can be secondary to acquired causes such as superior vena cava (SVC) occlusion and development of a mediastinal right-to-left shunt. Such shunts allow undisturbed passage of thromboemboli to bypass the pulmonary circulation and enter the systemic circulation. This report presents a case of paradoxical cerebral embolism due to a right-to-left shunt originating from occlusion of the SVC. The etiology of the SVC occlusion stems from a prior central venous access line used for treatment of lymphoma. The patient underwent endovascular treatment with successful coil embolization of the mediastinal shunt.

Stanford type IV venous collateral blood flow following complete chronic occlusion of the superior vena cava in a patient with lung cancer

In superior vena cava occlusion, multiple collateral pathways develop to maintain venous drainage. Major patterns and pathways of venous collateral blood flow are well described, but rarely in complete chronic superior vena cava occlusion secondary to malignancy. A 59-year-old man with facial and upper extremity edema had a severely compressed superior vena cava at the initial diagnosis of stage IV mediastinal lung adenocarcinoma. The occlusion of superior vena cava progressed. After 10 months of treatment, the complete occlusion led to mild symptoms of hoarseness, muscle weakness, cough, and slight upper extremity edema. Venography clearly illustrated well-developed venous collateral blood flow through lateral thoracic, azygos-hemiazygos, and vertebral collateral venous pathways classified as Stanford type IV. The patient survived for a total of 20 months. He maintained Eastern Cooperative Oncology Group performance status of 1-2 until 2 months before death without severe symptoms of superior vena cava occlusion. This case described a rarely occurring venographic demonstration of well-developed Stanford type IV collateral pathway. Moreover, even with complete superior vena cava occlusion, well-developed Stanford type IV lateral thoracic collateral pathway can compensate for the venous flow without deterioration of performance status for a long period in certain cases.

Computed Tomography Findings Associated With 30-Day Mortality in Patients With Malignant Superior Vena Cava Syndrome

OBJECTIVE

The objective of this study was to identify radiological and clinical factors associated with early mortality in malignant superior vena cava syndrome (SVCS).

MATERIALS AND METHODS

Chest computed tomography studies of 127 patients with malignancy-associated SVCS were retrospectively reviewed. Involvement of SVC and tributaries, pleural and pericardial effusions, pulmonary artery involvement, and ancillary findings were documented. Univariate and multivariate models determined associations between radiological and clinical variables, and 30-day mortality.

RESULTS

Thirty-day mortality rate was 16.5% (n = 21). Factors associated with 30-day mortality on univariate analysis included age, cancer stage, SVCS clinical severity, left jugular vein obstruction, number of involved veins, pulmonary arteries involvement, and presence of pleural effusions. Age, SVCS clinical severity, number of veins involved, and pleural effusions were positively associated with 30-day mortality on multivariate analysis.

CONCLUSIONS

Selected clinical and radiological variables are associated with early death in malignant SVCS. These factors may identify a subgroup of patients who may benefit from treatment escalation.

Prevalence and characteristics of intravertebral enhancement on contrast-enhanced CT scans in cancer patients

STUDY DESIGN

This was a single center, retrospective observational study.

OBJECTIVE

to investigate-in a cancer population-the prevalence and hallmarks of intravertebral enhancement (IVE) detected on contrast-enhanced CT.

SUMMARY OF BACKGROUND DATA

Intravertebral enhancements secondary to iodinated contrast stagnation have been described. Cancer patients have an increased risk of perivertebral venous thrombosis or stenosis secondary to several risk factors (cancer or drug induced hypercoagulability, deterioration of venous flow linked to catheter insertion, prolonged immobilization). In case of a high density lesion identified on CT, the diagnostic choice between metastasis and contrast media within bone marrow vessels may be an issue, especially as oncologic follow-up CT scans are usually performed with contrast medium injection.

METHODS

2572 contrast-enhanced body CT scans performed in cancer patients over 3 months in the medical imaging department of a university hospital were retrospectively reviewed. IVE was sought when paravertebral venous collateral circulation was detected and bone metastasis ruled out and classified as linear or nodular. Their locations within vertebra, their relation to the injection side and the predominant collateral venous network side were evaluated.

RESULTS

Sixty-seven (2.8%) patients had a collateral paravertebral venous system and among them 21 had IVE (37%). There were 208 IVE locations involving 75 vertebrae. 199 IVE were linear-shaped (95.7%) and 9 nodular-shaped (4.3%). 80.8% were located between C6 and T4. 88.9% were localized in the vertebral body. 73.1% were located medially or ipsilateral to the injection side.

CONCLUSION

Intravertebral enhancement is found in 37% of the patients with paraspinal collateral venous circulation when a CT scan is performed for cancer. The ipsilateral or medial position of the IVE relative to the injection side and the side of the dominant perivertebral venous system, and the possibility of connecting the IVE to a paravertebral vein may be in favor of vascular opacification.

Retrospective analysis of intravertebral collateral enhancement in patients with central venous obstruction

OBJECTIVE

To compare prevalence and patterns of intravertebral collateral enhancement in patients with and without central venous obstruction (CVO).

MATERIALS AND METHODS

Chest CTs performed between 1/1/2000 and 12/15/2012 with reports containing terms indicating CVO were identified. All contrast enhanced CTs were examined for the presence of CVO and collateral venous pathways. If intravertebral collateral enhancement was present, the pattern was recorded as nodular, linear, or both.

RESULTS

In 209 suspected cases of CVO, 53 (25 %) were confirmed with obstruction and 156 (75 %) were without obstruction. In patients with CVO, 47 % (25/53) demonstrated collateral venous flow through an intravertebral marrow pathway compared to 5 % (8/156) of patients without CVO (P < 0.0001). The most common level of enhancement was the upper thoracic spine, involving only the vertebral body. Nodular, linear, and combined nodular-linear enhancement patterns were seen with similar frequency. Nodular intravertebral collateral enhancement was mistaken for sclerotic metastases in 33 % (3/9) of cases.

CONCLUSION

Intravertebral collateral enhancement was seen in almost half the patients with CVO and when nodular enhancement is present, it is important to differentiate between metastatic lesions and enhancement related to CVO.

Vanishing bone metastases: a pitfall in contrast-enhanced CT in patients with venous thrombosis

Enhancement patterns of visceral venous collaterals are well documented in cases of superior vena cava obstruction. Only recently has intraosseous venous collateral enhancement been described. We describe an unusual case of vertebral marrow enhancement in the lower thoracic spine related to venous collateral circulation caused by an incidental hemiazygos thrombus. Misinterpretation of this finding can lead to the erroneous interpretation of sclerotic bone metastases.

Pseudopathologic vertebral body enhancement in the presence of superior vena cava obstruction on computed tomography

BACKGROUND CONTEXT

Superior vena cava (SVC) obstruction can cause the development of collateral vessels. During contrast-enhanced thoracic computed tomography (CT), contrast material may reflux into the collaterals such as paravertebral venous plexus. However, an unusual pseudopathologic vertebral body enhancement on CT in the presence of SVC obstruction has not been studied previously.

PURPOSE

To demonstrate clinical presentation and imaging findings of pseudopathologic vertebral body enhancement in patients with SVC obstruction.

STUDY DESIGN

Retrospective study of diagnostic CT images examined at our clinic.

PATIENT SAMPLE

From March, 2009 to September, 2012, a retrospective radiologic database review was performed to identify patients with obstruction of SVC causing contrast reflux into collateral vessels and presented with an unusual vertebral body enhancement on thoracic CT. Thirteen patients (11 men, mean age 51.4 years) with vertebral body enhancement were enrolled.

OUTCOME MEASURES

Enhancement patterns of vertebral bodies were classified as nodular enhancement with round shape occupying less than one-third of vertebral body or polygonal enhancement occupying greater than or equal to one-third of vertebral body on axial image. The locations of enhanced areas within vertebral bodies were described using right lateral/central/left lateral, anterior/posterior, and upper/middle/lower in the x-, y-, or z-axis directions, respectively.

MATERIALS AND METHODS

Enhancement patterns, locations, and the presence of a connection between vertebral body enhancement and the paravertebral venous plexus were evaluated.

RESULTS

A total of 39 vertebral body enhancements were found in the 13 patients, involving cervical (n=12), thoracic (n=25), or lumbar (n=2) vertebrae. Vertebral body enhancements showed a nodular (n=19) or a polygonal (n=20) pattern. The central portions of vertebral bodies were more frequently involved. The connection to the paravertebral venous plexus was observed in 34 lesions (87.2%).

CONCLUSIONS

Patients with SVC obstruction with extensive collateral vessels might exhibit a pseudopathologic vertebral enhancement. They tended to involve the central portion of the vertebral body, and most of them showed connection to the paravertebral venous plexus.

Downhill esophageal varices: a prevalent complication of superior vena cava obstruction from benign and malignant causes

OBJECTIVE

Downhill esophageal varices (DEV) usually develop secondary to superior vena cava (SVC) obstruction. Downhill esophageal varices have been less well characterized compared to uphill varices. The aim of the study was to characterize the anatomy and etiology of DEV by contrast-enhanced computed tomography.

METHODS

Patients with SVC obstruction were included in the study. Downhill esophageal varices were defined as discrete esophageal submucosal or mucosal vessels. Ten random computed tomographic scans were assessed as controls.

RESULTS

Downhill esophageal varices were seen in 11 of 36 patients. Three types of varices were observed. Between 1 and 6 varices were seen in each patient with a diameter of 1 to 5 mm.

CONCLUSIONS

Downhill esophageal varices can be seen in 30% of patients with SVC obstruction. They have several patterns and are mostly systemic-to-systemic collaterals. The most common etiology associated with DEV is renal failure. Downhill esophageal varices are of small caliber, this may in part account for less frequent bleeding compared to uphill varices.

CT demonstration of the extracardiac anastomoses of the coronary veins in superior vena cava or left brachiocephalic vein obstruction

CT scans in four cases of chronic superior vena cava or left brachiocephalic vein obstruction demonstrate a systemic-to-cardiac collateral venous pathway through anastomoses between the pericardial branches of systemic veins and the presumed adventitial veins of the ascending aorta and pulmonary trunk. These adventitial veins then drain into tributaries of the anterior cardiac veins or ventricular coronary veins.

Compensatory dilatation of the Azygos Venous system Secondary To Superior Vena Cava Occlusion

Superior vena cava (SVC) occlusion can be clinically recognized in the acute setting when the stenosing process does not allow the development of collateral venous channels, which guarantee the venous drainage to the right heart. On the contrary, when the obstruction develops progressively, the diagnosis of SVC obstruction may remain undiagnosed. In the present case, the presence of SVC thrombosis was purely coincidental. In fact, the obstruction was first noticed on diagnostic tests performed because of the malfunction of a totally implantable Porth a Cath placed into the superior vena cava (through right subclavian access), five years before, in a patient suffering from non-Hodgkin disease. Venography is the most appropriate diagnostic methodology which reveals the presence of a dilated azygos vein as a compensatory mechanism. Comparison with computed tomography allows to confirm the diagnosis and to identify the possible causes. Dilatation of the azygos vein, secondary to superior vena cava thrombosis, although a rare event, should be taken into consideration in those patients with CVC and who present with frequent episodes of deep venous thrombosis.

Imaging the inferior vena cava: a road less traveled

A broad spectrum of congenital anomalies and pathologic conditions can affect the inferior vena cava (IVC). Most congenital anomalies are asymptomatic; consequently, an awareness of their existence and imaging appearances is necessary to avoid misinterpretation. Imaging also plays a central role in the diagnosis of Budd-Chiari syndrome secondary to membranous obstruction of the intrahepatic IVC. Primary malignancy of the IVC is far less common than intracaval extension of malignant tumors arising in adjacent organs, and imaging can accurately help determine the presence and extent of tumor thrombus, information that is crucial for surgical planning. However, the radiologist should be aware that artifactual filling defects at computed tomography and magnetic resonance imaging can mimic true thrombus in the IVC and must be able to differentiate true from pseudo filling defects. Other imaging findings such as flat IVC and early enhancement of the IVC are useful in limiting the differential diagnosis. Familiarity with the imaging features of the various congenital and pathologic entities that can affect the IVC is paramount for early diagnosis and management.

CT appearances of congential and acquired abnormalities of the superior vena cava

A wide spectrum of congenital and acquired abnormalities can affect the superior vena cava (SVC). Congenital anomalies can present either as incidental findings or be associated with underlying cardiac abnormalities; these include left-sided or double SVCs and anomalous venous drainages. Acquired conditions involving the SVC, including SVC obstruction syndrome, can be secondary to extrinsic compression or intrinsic occlusion. The CT appearances, the incidence, and associations of these conditions are discussed.

Focal Hepatic Activity During Ventilation-Perfusion Scintigraphy Due to Systemic-Portal Shunt Due to Superior Vena Cava Obstruction From Histoplasmosis-Induced Fibrosing Mediastinitis

A 59-year-old woman with a history of fibrosing mediastinitis secondary to histoplasmosis diagnosed on mediastinoscopy presented with dyspnea. A ventilation-perfusion scan demonstrated decreased perfusion to the entire right lung. In addition, the perfusion images demonstrated focal abnormal activity in part of the liver. On computed tomography of the chest, there was significant soft tissue opacification in the mediastinum occluding the right pulmonary artery, with passage of the injected contrast via collateral vessels to the liver. The main collateral pathway was via the right internal thoracic vein and the umbilical vein. Pulmonary angiography confirmed complete occlusion of the right pulmonary artery.

The off-pump Fontan procedure by simply cross-clamping the inferior caval vein

BACKGROUND

We previously used the Fontan procedure, when applicable, by placing a temporary bypass from the inferior vena cava to the atrium. Alternatively, we have striven to achieve the procedure even without use of a temporary bypass in patients having collaterals between the inferior vena cava and the superior vena cava, so as to simplify the procedure. The azygous vein was intentionally left patent at the bidirectional Glenn procedure in the most recent 9 patients, expecting reasonable venovenous communication at Fontan completion. Surgical results will be described for the preliminary experience.

METHODS

Since 2001, this alternative technique has been attempted in 34 patients undergoing the staged Fontan procedure, and eventually used in 22. Duration between the staged procedures was 4 to 108 months (median, 10 months). We considered that the technique was feasible unless femoral venous pressure exceeded 20 mm Hg immediately after cross-clamping the inferior vena cava. Although catheterization before the Fontan completion illustrated development of venovenous collaterals in 14 patients, oxygen saturation remained greater than 80% throughout the period of the bidirectional Glenn physiology.

RESULTS

In all 22 patients, the extracardiac channel was readily reconstructed with an excellent surgical field of view, without operative mortality. On cross-clamping the inferior vena cava, the systemic circulation could be well maintained by administration of dopamine. Oxygen saturation immediately became approximately 97% to 100%. Maximal pressure gradient was 11 +/- 5 mm Hg between the superior vena cava and the femoral vein. Postoperatively, serum concentration of enzymes did not critically increase (maximal aspartate transaminase, 96 +/- 89 U/L; alanine transaminase, 65 +/- 59 U/L; total bilirubin, 1.8 +/- 1.1 mg/dL; creatine kinase, 437 +/- 230 U/L).

CONCLUSIONS

This alternative technique, when feasible under the current criteria, was simple and did not provide any clinically significant impediments.

The superior vena cava syndrome caused by malignant disease

OBJECTIVE

The superior vena cava (SVC) obstruction by malignant diseases is either by direct invasion and compression or by tumour thrombus of the SVC. Whatever is its cause, obstruction of the SVC causes elevated pressure in the veins draining into the SVC and increased or reversed blood flow through collateral vessels. Severity of the syndrome depends on the collateral vascular system development. Therefore, imaging of the collateral veins with variable location and connection is important in determining the extension and management of the disease. Our aims are to describe collateral vessels of the superior vena cava syndrome (SVCS) related with the malignant diseases and to assess the ability of multi-detector row CT with multiplanar and 3D volume rendering techniques in determining and describing collateral circulations.

MATERIALS AND METHODS

We present CT angiography findings of seven patients with small cell carcinoma of the lung (n = 2), squamous cell carcinoma of the lung (n = 3), Hodgkin disease of the thorax (n = 1), and squamous cell carcinoma of the oesophagus (n = 1). The patients received contrast-enhanced CT scans of the chest and abdomen on a multi-detector row CT during breath holding at suspended inspiration.

RESULTS

CT images revealed the cause and level of the SVC obstruction in all patients with axial and multiplanar reconstructed images. The SVC showed total obstruction in five patients and partial obstruction in two patients. The most common experienced collateral vessels were azygos vein (6), intercostal veins (6), mediastinal veins (6), paravertebral veins (5), hemiazygos vein (5), thoracoepigastric vein (5), internal mammary vein (5), thoracoacromioclavicular venous plexus (5), and anterior chest wall veins (5). While one case showed the portal-systemic shunt, V. cordis media and sinus coronarius with phrenic veins were enlarged in two cases, and the left adrenal vein was enlarged in a patient. In one case, the azygos vein with reversed blood flow was drained into both inferior vena cava and hemiazygos vein with the left renal vein.

CONCLUSION

Multi-detector row CT with multiplanar and 3D imaging is an effective tool in evaluation of the SVCS and has a greater advantage than the other imaging techniques. 3D volume rendering is a useful technique in determining and describing collateral circulations in addition to the primary disease process.

Esophageal varices as a rare complication of central venous dialysis tunneled cuffed catheter

Long-term complications of tunneled cuffed catheters include infection and catheter and venous thrombosis. We present a case of a central venous dialysis tunneled cuffed catheter complicated with esophageal varices resulting from superior vena cava obstruction.

Perioperative Management with Epidural Anesthesia for a Parturient with Superior Vena Caval Obstruction

Perioperative management of patients with superior vena cava obstruction presents an anesthetic challenge because of severe cardiopulmonary compromise. This is particularly important in the parturient because of increased upper airway edema and inferior vena caval compression. We describe the management of a parturient who presented at 34 wk of gestation with signs and symptoms of superior vena cava obstruction from metastatic breast cancer. The patient was scheduled for a cesarean delivery followed by chemotherapy, as other therapies were deemed excessively risky because of the anatomic characteristics of the large mediastinal mass. This report describes the successful use of regional anesthesia in this setting and discusses the relevant anesthetic and perioperative management considerations for this complex scenario.

IMPLICATIONS

Perioperative management of patients with superior vena caval obstruction presents an anesthetic challenge because of the severe cardiopulmonary compromise. This case report describes a parturient who presented for cesarean delivery with superior vena caval obstruction resulting from metastasis from breast cancer.

Collateral Pathways in Thoracic Central Venous Obstruction

We illustrate the spectrum of venous collateral pathways caused by the thoracic central venous obstruction with direct spiral computed tomography (CT) venography and 3-dimensional reconstruction images. Venous structures that can be demonstrated with CT venography include the jugular veins; the subclavian and brachiocephalic (innominate) veins; the internal and lateral thoracic veins; the superior and inferior venae cavae; the pericardiophrenic veins; the azygos, hemiazygos, and accessory hemiazygos veins; and the intercostal veins.

Thoracic venous anatomy multidetector row CT evaluation

Two-dimensional CT angiography provides much information of the systemic and pulmonary thoracic veins. The combination of MDCT and volume-rendering techniques postprocessing provides higher-quality data sets and a method fully to harness the potential for image display and interpretation. Although this may not radically alter sensitivity for detection of systemic or pulmonary venous pathology it does provide a more comprehensive and sophisticated evaluation through volume acquisition and interpretation.