MR imaging in inferior vena cava thrombosis

Experimental multiparametric magnetic resonance imaging characterization of iliocaval venous thrombosis pathological changes

OBJECTIVE

Iliocaval thrombotic obstruction is a challenging condition, especially because thrombus age and corresponding pathological remodeling at presentation are unknown, which directly impacts management. Our aim was to assess the ability of magnetic resonance imaging (MRI) in determining age thresholds of experimentally created inferior vena cava (IVC) thrombosis in pigs.

METHODS

We used a previously described swine model of IVC thrombosis. The animals underwent MRI at baseline, immediately after thrombosis creation, and after a follow-up period extending from 2 to 28 days. Thirteen pigs were divided into three groups according to disease chronicity: acute group (AG; n = 5), subacute group (SAG; n = 4), and chronic group (CG; n = 4), with a mean thrombosis age of 6.4 ± 2.5 days, 15.7 ± 2.8 days, and 28 ± 5.7 days, respectively. A T1-weighted volumetric interpolated breath-hold examination sequence was used to anatomically delineate IVC thrombus as a region of interest. Three other MRI sequences were used to assess the thrombus signal.

RESULTS

The Kruskal-Wallis test showed a statistically significant difference in T1 relaxation times after contrast injection (P = .026) between the three groups of chronicity. The AG (360.2 ± 102.5 ms) was significantly different from the CG (336.7 ± 55.2 ms; P = .003), and the SAG (354.1 ± 89.7 ms) was significantly different from the AG (P = .027). There was a statistically significant difference in native T2 relaxation times (P = .038) between the three groups. The AG (160 ± 86.7 ms) was significantly different from the SAG (142.3 ± 55.4 ms; P = .027), and the SAG was significantly different from the CG (178.4 ± 11.7 ms; P = .004).

CONCLUSIONS

This study highlighted MRI characteristics in a swine model that might have the potential to significantly differentiate subacute and chronic stages from an acute stage of deep vein thrombosis in humans. Further clinical studies in humans are warranted.

CLINICAL RELEVANCE

In addition to providing a better understanding of venous thrombosis remodeling over time, magnetic resonance imaging has the potential to be a tool that could allow us to characterize the composition of venous thrombus over an interval, allowing for a refined analysis of the local evolution of venous thrombosis. We propose a noninvasive and innovative method to characterize different thresholds of chronicity with magnetic resonance imaging features of central deep vein thrombosis of the inferior vena cava experimentally obtained using a totally endovascular in vivo swine model, mimicking human pathophysiology. Being able to determine these features noninvasively is critical for vascular specialists when it comes to choosing between fibrinolytic therapy, percutaneous thrombectomy, or surgical management.

Review article inferior vena cava thrombosis: a case series of patients observed in Taiwan and literature review

Inferior vena cava thrombosis (IVCT) is rare and can be under-recognized. However, the associated complications and mortality may be severe. We report the first case series of IVCT observed in Taiwan with a brief literature review. Eight Taiwanese patients with IVCT between May 2012 and December 2019 were enrolled in this study. Deep venous thrombosis (DVT, 8/8) and pulmonary embolism (5/8) were reported. Various risk factors were identified, including an unretrieved inferior vena cava (IVC) filter, pregnancy, surgery, presence of lupus of anticoagulants, essential thrombocythemia, antithrombin deficiency, and hemoglobin H disease. Of note, four of our patients experienced complete IVC thrombosis with bilateral lower extremity swelling (due to DVT) and abdominal wall superficial venous dilatation, while four other patients presented with partial IVCT and unilateral DVT. The etiology, clinical characteristics, presentations, diagnosis, and treatment of IVCT were reviewed.

First Magnetic Resonance Managed by a Cardiology Department in the Spanish Public Healthcare System. Experience and Difficulties of an Innovative Model

Magnetic resonance (MR) is considered the gold standard in the assessment of myocardial morphology, function, perfusion, and viability. However, its main limitation is its scarce availability. In 2014, we installed the first MR scanner exclusively managed by a cardiology department within the publicly-funded Spanish healthcare system with the aim of improving patient-care, training and research in the department. In the time interval analyzed, July 2014 to May 2017, 3422 cardiac MR scans were performed (32minutes used per study; 96% with good quality; 75% with contrast media administration). The most prevalent clinical indications were cardiomyopathy (29%) and ischemic heart disease (12%). Twenty-five percent of studies were conducted in the context of research protocols. Follow-up studies predominated among outpatients, while pretherapeutic assessment was more common in hospitalized patients. The presumptive diagnosis was changed by cardiac MR scanning in up to 20% of patients investigated for ischemic heart disease. The installation and operative management of an MR scanner in our cardiology department has allowed us to integrate this technique into daily clinical practice, modify our clinical protocols, optimize access to this technology among cardiac patients, improve training, and conduct clinical research.

[Level IV inferior vena cava tumor thrombus : A rare diagnosis in patients with renal cell carcinoma]

Renal cell carcinoma in combination with a supradiaphragmatic tumor thrombus is a rare tumor entity. Radical surgery including nephrectomy and thrombectomy is still considered standard treatment. The extent of the tumor thrombus should be preoperatively evaluated by MRI and TEE. An interdisciplinary team is important for surgery planning and realization. Despite the known risks of an operation, a longer overall survival is achieved.

Catheter directed interventions for inferior vena cava thrombosis

Inferior vena cava (IVC) thrombosis, although similar in many aspects to deep venous thrombosis (DVT), has distinct clinical implications, treatments and roles for endovascular management. Etiologies of IVC thrombosis vary from congenital malformations of the IVC to acquired, where indwelling IVC filters have been implicated as a leading cause. With an increasing incidence of IVC thrombosis throughout the United States, clinicians need to be educated on the clinical signs and diagnostic tools available to aid in the diagnosis as well as available treatment options. Untreated IVC thrombus can result in serious morbidity and mortality, both in the acute phase with symptoms related to venous outflow occlusion and embolism, and in the long-term, sequelae of post-thrombotic syndrome (PTS) related to chronic venous occlusion. This manuscript will discuss the clinical presentation of IVC thrombosis, diagnostic and treatment options, as well as the role of endovascular management.

Etiology and treatment of acute inferior vena cava thrombosis

Inferior vena cava thrombosis (IVCT) is a rare but severe disease that is associated with a high rate of mortality. IVCT can be categorized into primary versus secondary thrombosis dependent upon the underlying pathophysiology. The diagnosis includes both clinical probability assessment as well as the imaging evaluation. The optimal therapeutic strategy remains the target of continued research. Although anticoagulation therapy remains fundamental in treating IVCT, its inherent limitations have led to the use of minimally invasive, endovascular treatment options, including transcatheter thrombolysis, mechanical thrombectomy or a combination of these techniques. This review focuses on the etiology, diagnostic assessment, and endovascular treatment options for IVCT.

From the radiologic pathology archives: Adrenal tumors and tumor-like conditions in the adult: radiologic-pathologic correlation

Advanced imaging often reveals adrenal tumors and tumor-like conditions in both symptomatic and asymptomatic patients. When adrenal disease is clinically suspected, cross-sectional imaging can be helpful in evaluating the etiology of the patient's symptoms. When adrenal disease is incidentally identified, what the clinician and patient really want to know is whether the findings are benign or malignant, as this ultimately will affect their next step in management. Using radiologic-pathologic correlation, we broadly classify common, uncommon, and rare tumors and tumor-like conditions that can occur in the adrenal as benign or malignant. This classification follows predominant trends in observed biologic behavior while acknowledging those tumors that may behave in the minority in an unpredictable manner. We review the clinical background and presentation of functional adrenal tumors including Conn syndrome, Cushing syndrome, and catecholamine-secreting tumors, as well as their relationship with adrenal anatomy. We discuss a variety of benign tumors, including adrenal cortical adenoma (including oncocytoma) and pheochromocytoma, as well as uncommonly and rarely encountered tumors such as myelolipoma, hemangioma, lymphangioma, schwannoma, ganglioneuroma, and adenomatoid tumor. A variety of tumefactive but nonneoplastic lesions are addressed, including adrenal cortical hyperplasia, adrenal hemorrhage, adrenal cysts, and infections. Malignant tumors discussed include adrenal cortical carcinoma, the rare malignant pheochromocytoma, lymphoma, metastases, and sarcomas. For each tumor and tumor-like lesion, the clinical presentation, epidemiology, key imaging findings, diagnostic differential considerations, and management options are briefly addressed. Finally, an approach to the workup of suspected or incidentally discovered tumors is presented based on a selected literature survey and our clinical experience. Radiologists play an important role in identification and diagnosis of adrenal tumors and tumor-like conditions in both symptomatic and asymptomatic patients.

Inferior vena cava thrombosis: a review of current practice

Inferior vena cava (IVC) thrombosis remains under-recognised as it is often not pursued as a primary diagnosis. The aetiology of IVC thrombosis can be divided into congenital versus acquired, with all aetiological factors found among Virchow's triad of stasis, injury and hypercoagulability. Signs and symptoms are related to aetiology and range from no symptoms to cardiovascular collapse. Painful lower limb swelling combined with lower back pain, pyrexia, dilatation of cutaneous abdominal wall veins and a concurrent rise in inflammatory markers are suggestive of IVC thrombosis. Following initial lower limb venous duplex, magnetic resonance imaging (MRI) is the optimal non-invasive imaging tool. Aetiology directs treatment, which ranges from anticoagulation and lower limb compression to open surgery, with endovascular therapies increasingly favoured. The objective of this review is to assess current literature on the aetiology, presentation, investigation, treatment, prognosis and other factors pertaining to IVC thrombosis.

Coexistence of pheochromocytoma with uncommon vascular lesions

BACKGROUND

Pheochromocytoma/paragangliomas have been described to be associated with rare vascular abnormalities like renal artery stenosis. Coexistence of physiologically significant renal artery lesions is a compounding factor that alters management and prognosis of pheochromocytoma patients. Apart from individual case reports, data on such association in Indian population is not available. The aim of this study is to find the nature and prevalence of associated vascular abnormalities.

MATERIALS AND METHODS

From 1990 to 2010, a total of 50 patients were diagnosed with pheochromocytoma/paragangliomas. Hospital charts of these patients were reviewed retrospectively to identify those with unusual vascular abnormalities. Available literature was also reviewed.

RESULTS

Of the 50 patients with pheochromocytoma, 7 (14%) had coexisting vascular lesions including renal artery stenosis in 4, aortoarteritis in 1, aortic aneurysm in 1 and inferior vena cava thrombosis in 1. Pheochromocytoma was adrenal in 42 and extra adrenal in 8. Laparoscopic adrenalectomy was done in the patients. One patient with renal artery stenosis due to intimal fibrosis was subjected to percutaneous balloon angioplasty; the other three improved after adrenalectomy and lysis of fibrous adhesive bands. The patient with aortoarteritos was treated with oral steroids. Inferior vena cava thrombosis was reversed with anticoagulants. The patient with abdominal aortic aneurysm was advised for annual follow-up on account of its size of 4.5 cm and asymptomatic presentation.

CONCLUSION

There are multiple mechanisms that can lead to renal artery stenosis and other vascular abnormalities in a case of pheochromocytoma. A high index of suspicion is necessary to enable both entities to be diagnosed preoperatively and allow proper planning of surgical therapy. Incomplete diagnosis may lead to persistent hypertension postoperatively in a case of associated renal artery stenosis.

Pheochromocytoma with inferior vena cava thrombosis: An unusual association

Pheochromocytomas have been described in association with vascular abnormalities like renal artery stenosis. A 48-year-old man was admitted to our hospital with the complaints of headache, sweating, anxiety, dizziness, nausea, vomiting and hypertension. For last several days, he was having a dull aching abdominal pain. Abdominal computed tomography (CT) revealed the presence of a left adrenal pheochromocytoma. An inferior vena cava (IVC) venogram via the right jugular vein demonstrated occlusion of the IVC inferior to the right atrium. Surgical removal of pheochromocytoma was done, followed by anticoagulant treatment for IVC thrombosis, initially with subcutaneous low molecular weight heparin, and then with oral warfarin, resulting in restoration of patency. To the best of our knowledge, the occurrence of pheochromocytoma in IVC thrombosis has not been reported so far from India. Possible mechanisms of such an involvement are discussed.

Adrenal imaging: a comprehensive review

The discovery of an incidental adrenal mass (adrenal incidentaloma) continues to rise with the increasing use of cross-sectional imaging. Although most adrenal lesions are benign and asymptomatic, radiologists should guide evaluation of these lesions, whether benign or malignant. This article reviews the various imaging techniques used to evaluate adrenal masses and their relative strengths and weaknesses. It focuses on the most prevalent adrenal pathologies and their typical imaging characteristics, and concludes with a brief discussion of developing techniques, including diffusion-weighted imaging and dual-energy CT.

Adrenocortical carcinoma: the range of appearances on CT and MRI

OBJECTIVE

Adrenocortical carcinoma (ACC) is a rare, aggressive tumor arising from the adrenal cortex that typically presents late with a large mass. The increased use of cross-sectional imaging for unrelated reasons has led to a greater number of ACCs being detected incidentally at an earlier stage. Recognition of the typical clinical, biochemical, and imaging findings is imperative for rapid diagnosis, prompt intervention, and early use of the appropriate therapy.

CONCLUSION

Cross-sectional imaging with CT and MRI is essential for determining the extent of local and distant tumor spread. Complete surgical resection is currently the only potentially curative treatment of ACC, and the information attained from CT and MRI is important to guide surgery and further patient management.

Acute Thrombosis of Inferior Vena Cava in a Pregnant Woman Presenting with Sciatica: A Case Report

A 20-year-old pregnant woman was admitted to our department with symptoms of deep venous thrombosis in the left lower extremity and excessive lumbar pain. Low-molecular-weight heparin was administered. She recovered with this treatment, however, severe lumbar pain continued. A lumbar magnetic resonance image showed dilated epidural veins compressing the roots and acute thrombosis of the inferior vena cava extending to renal veins. During the same period she had acute deep venous thrombosis in her right leg. An urgent venous thrombectomy was performed. Sciatica and deep venous thrombosis resolved after the operation. Low-molecular-weight heparin was administered until the end of her pregnancy.

"Bull's-eye" sign on gadolinium-enhanced magnetic resonance venography determines thrombus presence and age: a preliminary study

PURPOSE

Venous thrombosis is associated with a significant inflammatory response, which can be visualized by gadolinium magnetic resonance venography (MRV). Gadolinium extravasates into tissue during inflammation, producing perithrombus enhancement on magnetic resonance scanning. This study determines (1) whether gadolinium enhancement occurs during deep venous thrombosis (DVT); and (2) whether this enhancement changes with time and can therefore establish the age of thrombus.

METHODS

Patients with a diagnosis of iliofemoral DVT by duplex ultrasound who were referred for MRV to document central thrombus extent were studied. T1 weighted images were obtained before and after gadolinium injection (0.1 mmol/kg); repeat scans were obtained up to 3 months thereafter. At the level of maximum thrombus, measurements of signal intensity were made at the periphery (rim), and the center of the thrombosed vein, as well as the contralateral normal vein, on images after gadolinium enhancement. Rim-center vein signal intensity ratios were then calculated and followed.

RESULTS

A total of 39 scans were obtained in 14 patients (eight men, six women). The thrombosed veins were enlarged, with a peripheral rim of enhancement ("bull's-eye" sign). The rim-center ratio for thrombosed veins (2.16 +/- 0.18) was different from that of normal veins (0.66 +/- 0.10; n = 39; p < 0.001). For all acute studies (< or = 14 days) the rim-center ratio was 2.38 +/- 0.17 (n = 31), whereas for all chronic studies (> 14 days) the rim-center ratio was 1.29 +/- 0.44 (n = 8; p = 0.001). Among patients who underwent both early and late studies, the rim-center ratio dropped significantly, from 2.33 +/- 0.20 acutely to 1.29 +/- 0.44 in chronic studies (n = 8; p = 0.03). One patient with active malignancy had a paradoxic increase in rim-center ratio over time and a clinical recurrence of symptoms, suggesting active thrombosis.

CONCLUSIONS

We conclude that (1) a pattern of peripheral gadolinium enhancement (bull's-eye sign) is seen around acutely thrombosed veins on gadolinium-enhanced MRV, facilitating DVT diagnosis; and (2) the ratio of signal intensity at the rim versus the center of the thrombosed vein may be a good discriminator of acute compared with chronic DVT, which may help direct therapy.