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

Deep vein thrombosis in the thigh: MR imaging in two cases with atypical presentations

Deep vein thrombosis (DVT) is a common clinical problem affecting the lower extremities. Prompt imaging of suspected DVT is helpful for rapid diagnosis and proper treatment. However, patients without clear predisposing factors for DVT may be directed to alternative diagnoses of a musculoskeletal disorder. The few case reports and studies of magnetic resonance (MR) imaging of unsuspected DVT are limited to the calf and knee. Here, we report two cases with a rare presentation of thigh MR imaging of unsuspected DVT. Identifying branching, abnormal intraluminal signals on fluid-sensitive imaging, or rim-enhancing tubular structures within the edema of the thigh muscle is important for differentiating intramuscular DVT from other thigh pathologies.

Efficacy of Shear Wave Elastography in the Differentiation of Acute and Subacute Deep Venous Thrombosis

ABSTRACT

It is important to know the age of clot formation to determine an appropriate treatment for deep vein thrombosis (DVT). The present study aims to differentiate between acute and subacute DVT using the shear wave elastography (SWE) technique. Patients with complaints no longer than 4 weeks and who were found to have early-stage (acute-subacute) thrombus on ultrasound (US) between January 2020 and May 2020 were included in the study. All of the patients underwent SWE using a Philips Healthcare EPIQ 5 Ultrasound System Inc. device with a high-resolution linear US probe (eL18-4, 22-2 MHz). Included in the study were 50 patients, including 23 with acute DVT and 27 with subacute DVT. Of the patients, 22 were women and 28 were men, and the mean age was 46.32 ± 11.33 years (range: 24-74 years). The mean SWE value was 2.63± 0.16 (2.39-2.96) in patients with acute DVT and 3.34± 0.31 (2.65-3.88) in patients with subacute DVT. The findings were statistically significant in the comparison of the 2 groups using an independent samples t test (P < 0.001). In the receiver operating characteristic analysis, the area under the curve was found to be 97.6%. When the cutoff value was taken as 2.85 according to the area under the curve, sensitivity was found to be 96.3%, and specificity was 91.3%. Thrombus stage plays a critical role in treatment decisions in DVT in the lower extremities. The present study reveals that the shear wave US elastography technique can be used to discriminate between acute and subacute DVT.

Iliac Vein Stenosis: Is the Data Strong Enough for Stenting in the Young Pelvic Venous Disorders (PeVD) Population?

Iliac vein stenosis is a clinical condition resulting from external compression of the iliocaval venous unit with the consequent remodeling of the vascular wall, hemodynamic alterations, and predisposition to venous thrombosis. As such, the most common indications for percutaneous endovascular iliac vein stenting supported by the literature, include the management of thrombotic and non-thrombotic iliac venous lesions associated with advanced chronic venous disease (CVD). However, its clinical presentation is variable, and it may also include features associated with PeVD such as chronic pelvic pain, perineal heaviness, urinary urgency, postcoital pain, and vulvar or superficial non-saphenous veins varicosities. In this setting, the management revolves around the relieving venous obstruction and restoring normal blood flow through the compressed vein with percutaneous endovascular iliac vein stenting, that can be augmented with ovarian vein embolization (OVE) or direct embolization of the superficial varices. Given the heterogeneity of PeVD presentation and the lack of high-level quality data in outcomes for iliac vein stenosis stenting, this review will discuss the current evidence available for this intervention and clinical issues to consider when evaluating these patients.

Non-contrast-enhanced magnetic resonance imaging: Objective figures in differentiation between acute and chronic deep venous thrombosis in the lower extremities

BACKGROUND

Deep vein thrombosis is a severe health problem. Treatment options may differ between acute and chronic deep vein thrombosis. Thus, distinguishing acute from chronic deep vein thrombosis is essential for patients with deep vein thrombosis.Triggered angiography non-contrast enhanced is an innovative magnetic resonance imaging protocol that may provide objective evidence in differentiating acute from chronic deep vein thrombosis.

METHOD

We prospectively collected information on consecutive patients who had been evaluated through triggered angiography non-contrast enhanced magnetic resonance imaging for venous pathology in their lower extremities at a vascular wound care center in a tertiary hospital between April 2017 and January 2020. Patients included were divided into two groups with the onset time cutoff point of 21 days. All were undergone non-contrast-enhanced magnetic resonance imaging evaluation. Non-contrast-enhanced magnetic resonance imaging images were evaluated by a radiologist, and lower extremity venous thrombosis, collateral-vein development, and subcutaneous honeycombing were emphasized. Cohen's kappa coefficient was used to measure interrater agreement between the development of collateral veins, subcutaneous honeycombing, and symptom onset over 21 days.

RESULTS

Interrater agreement analysis revealed that the development of collateral veins was substantially correlated with the onset of symptoms over 21 days (Table 1). Additionally, the development of subcutaneous honeycombing detected through triggered angiography non-contrast enhanced magnetic resonance imaging also substantially agreed with the onset of symptoms over 21 days (Table 2).

CONCLUSION

The diagnostic power of triggered angiography non-contrast enhanced magnetic resonance imaging in deep vein thrombosis is rival to current gold standard, color Doppler sonography. Triggered angiography non-contrast enhanced magnetic resonance imaging provides objective information on onset timing in patients with deep vein thrombosis that could differentiate acute from chronic deep vein thrombosis and provides guidance for treatment planning.

DANTE-SPACE: a new technical tool for DVT on 1.5T MRI

The aim of the study was to compare CE-MRV with DANTE-SPACE on a 1.5T MRI system for the diagnosis of DVT. The patients were diagnosed with deep venous thrombosis of the lower extremities based on swelling, pain, and superficial varicose veins of the lower extremities. MRI examination confirmed the diagnosis. DANTE-SPACE images were obtained before the conventional contrast-enhanced MRV, which uses gadolinium. The scanning field started from the end of the inferior vena cava to the end of the ankle, divided into five observation segments, namely, the common iliac vein, external iliac vein, femoral vein, popliteal vein, and calf vein. The DANTE-SPACE and CE-MRV results were used for a consistency analysis. For the DANTE-SPACE and CE-MRV images, the signal intensity ratios of the thrombus/cavity and thrombus/muscle were calculated, and the ratio difference was compared using the paired t test. Twenty-six patients completed the examination; one of the patients underwent a right lower limb amputation, yielding a total of 255 lower limb vascular segments. The analysis of the DANTE-SPACE images showed that there were 14 iliac vein thromboses, 18 external iliac vein thromboses, 23 femoral vein thrombi, 21 popliteal vein thromboses, and 18 calf vein thromboses; these findings were consistent with the diagnostic results of CE-MRV. The ratio of the thrombus/cavity signal intensity measured in the DANTE-SPACE and CE-MRV images were as follows: 20.51 ± 12.96 vs. 0.51 ± 0.46; P < 0.05, n = 51; the difference was statistically significant. The ratio of the thrombus/muscle signal intensity measured on the DANTE-SPACE and CE-MRV images were as follows: 1.74 ± 0.57 vs. 0.99 ± 0.53; P < 0.05, n = 51; the difference was statistically significant. Compared with CE-MRV, DANTE-SPACE showed no significant difference in the ability to detect deep venous thrombosis of the lower extremities. DANTE-SPACE did not use contrast-enhancing agents and showed no evidence of inflammatory enhancement, and the display effect of small diameter veins was slightly poor. However, deep venous thrombosis of the lower extremities presents different levels of high signal in the DANTE-SPACE images, making it easy to identify and diagnose. It can also indicate the different components and age of the thrombus and help with the selection of a more accurate clinical treatment plan. MRI DANTE-SPACE is the preferred imaging modality for patients with deep venous thrombosis who are unable or unwilling to use gadolinium contrast agents.

Intraoperative Imaging and Image Fusion for Venous Interventions

Advanced imaging for intraoperative evaluation of venous pathologies has played an increasingly significant role in this era of evolving minimally invasive surgical and interventional therapies. The evolution of dedicated venous stents and other novel interventional devices has mandated the need for advanced imaging tools to optimize safe and accurate device deployment. Most venous interventions are typically performed using a combination of standard 2-dimensional (2D) fluoroscopy, digital-subtraction angiography, and intravascular ultrasound imaging techniques. Latest generation computer tomography (CT) and magnetic resonance imaging (MRI) scanners have been shown to provide high-resolution 3D and 4D information about venous vasculature. In addition to morphological imaging, novel MRI techniques such as 3D time-resolved MR venography and 4D flow sequences can provide quantitative information and help visualize intricate flow patterns to better understand complex venous pathologies. Moreover, the high-fidelity information from multiple imaging techniques can be integrated using image fusion to overcome the limitations of current intraoperative imaging techniques. For example, the limitations of standard 2D fluoroscopy and luminal angiography can be compensated for by perivascular and soft-tissue information from MRI during complex venous interventions using image fusion techniques. Intraoperative dynamic evaluation of devices such as venous stents and real-time understanding of changes in flow patterns during venous interventions may be routinely available in future interventional suites with integrated multimodality CT or MR imaging capabilities. The purpose of this review is to discuss the outlook for intraoperative imaging and multimodality image fusion techniques and highlight their value during complex venous interventions.

Depiction of lower limb venous anatomy in patients undergoing interventional deep venous reconstruction-the role of balanced steady state free precession MRI

OBJECTIVES

This study evaluates the use of balanced steady-state free precession MRI (bSSFP-MRI) in the diagnostic work-up of patients undergoing interventional deep venous reconstruction (I-DVR). Intravenous digital subtraction angiography (IVDSA) was used as the gold-standard for comparison to assess disease extent and severity.

METHODS

A retrospective comparison of bSSFP-MRI to IVDSA was performed in all patients undergoing both examinations for treatment planning prior to I-DVR. The severity of disease in each venous segment was graded by two board-certified radiologists working independently, according to a predetermined classification system.

RESULTS

In total, 44 patients (225 venous segments) fulfilled the inclusion criteria. A total of 156 abnormal venous segments were diagnosed using bSSFP-MRI compared with 151 using IVDSA. The prevalence of disease was higher in the iliac and femoral segments (range, 79.6-88.6%). Overall sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and the diagnostic ratio for bSSFP-MRI were 99.3%, 91.9%, 12.3, 0.007 and 1700, respectively.

CONCLUSION

This study supports the use of non-contrast balanced SSFP-MRI in the assessment of the deep veins of the lower limb prior to I-DVR. The technique offers an accurate, fast and non-invasive alternative to IVDSA. Advances in Knowledge: Although balanced SSFP-MRI is commonly used in cardiac imaging, its use elsewhere is limited and its use in evaluating the deep veins prior to interventional reconstruction is not described. Our study demonstrates the usefulness of this technique in the work-up of patients awaiting interventional venous reconstruction compared with the current gold standard.

Vein wall remodeling in patients with acute deep vein thrombosis and chronic postthrombotic changes

Essentials This study examined vein wall remodeling in acute thrombosis and postthrombotic syndrome (PTS). Thrombus-wall interface was measured using ultrasound real-time high definition zoom. Experimental cohorts demonstrated increased vein wall thickness localized to affected segments. Presence of thrombus or PTS are the most important factors affecting wall thickening.

SUMMARY

Introduction A few studies have investigated venous wall remodeling after venous thrombosis by using rodent models. Such information is lacking in humans. This study was designed to determine the acute and chronic effects of thrombus on the vein wall. Methods Patients aged > 16 years with deep vein thrombosis diagnosed by duplex ultrasound were assessed by the use of case-control methodology. Those with recurring thrombotic episodes, cardiorespiratory disease, terminal cancer, morbid obesity, penetrating trauma or significant inflammation were excluded. High-resolution ultrasound was employed to determine wall thickness, with strict quality criteria and inclusion of only technically adequate ultrasound images. Results Data were collected from patients with acute thrombosis (35), patients with chronic postthrombotic changes (15), and unaffected controls (32), with 853 total vein segments being analyzed. As compared with controls (mean 0.37 mm; 95% confidence interval [CI] 0.37-0.38 mm), venous wall thickness was increased in acute (mean 0.63 mm; 95% CI 0.61-0.64 mm) and postthrombotic (mean 0.85 mm; 95% CI 0.80-0.91 mm) venous segments. Ipsilateral, contralateral and unaffected control vein segments were not different. Ipsilateral segments were thicker than controls in postthrombotic syndrome (PTS) patients, but not in acute patients. Multiple regression analyses demonstrated small impacts of age and sex on vein wall thickness. Conclusions Wall thickness increases in all lower-tcglimb venous segments of patients with acute and postthrombotic disease. Age and sex may affect wall thickness, although further investigation is required to clarify their impact. The equivalence of ipsilateral and unaffected control segments suggests that acute vein wall remodeling is mediated through direct interaction with the thrombus, whereas remodeling in PTS patients may be affected by other factors.

Magnetic resonance venography and three-dimensional image fusion guidance provide a novel paradigm for endovascular recanalization of chronic central venous occlusion

OBJECTIVE

Endovascular recanalization is considered first-line therapy for chronic central venous occlusion (CVO). Unlike arteries, in which landmarks such as wall calcifications provide indirect guidance for endovascular navigation, sclerotic veins without known vascular branching patterns impose significant challenges. Therefore, safe wire access through such chronic lesions mostly relies on intuition and experience. Studies have shown that magnetic resonance venography (MRV) can be performed safely in these patients, and the boundaries of occluded veins may be visualized on specific MRV sequences. Intraoperative image fusion techniques have become more common to guide complex arterial endovascular procedures. The aim of this study was to assess the feasibility and utility of MRV and intraoperative cone-beam computed tomography (CBCT) image fusion technique during endovascular CVO recanalization.

METHODS

During the study period, patients with symptomatic CVO and failed standard endovascular recanalization underwent further recanalization attempts with use of intraoperative MRV image fusion guidance. After preoperative MRV and intraoperative CBCT image coregistration, a virtual centerline path of the occluded segment was electronically marked in MRV and overlaid on real-time two-dimensional fluoroscopy images. Technical success, fluoroscopy times, radiation doses, number of venograms before recanalization, and accuracy of the virtual centerline overlay were evaluated.

RESULTS

Four patients underwent endovascular CVO recanalization with use of intraoperative MRV image fusion guidance. Mean (± standard deviation) time for image fusion was 6:36 ± 00:51 mm:ss. The lesion was successfully crossed in all patients without complications. Mean fluoroscopy time for lesion crossing was 12.5 ± 3.4 minutes. Mean total fluoroscopy time was 28.8 ± 6.5 minutes. Mean total radiation dose was 15,185 ± 7747 μGy/m², and mean radiation dose from CBCT acquisition was 2788 ± 458 μGy/m² (18% of mean total radiation dose). Mean number of venograms before recanalization was 1.6 ± 0.9, whereas two lesions were crossed without any prior venography. On qualitative analysis, virtual centerlines from MRV were aligned with actual guidewire trajectory on fluoroscopy in all four cases.

CONCLUSIONS

MRV image fusion is feasible and may improve success, safety, and the surgeon's confidence during CVO recanalization. Similar to arterial interventions, three-dimensional MRV imaging and image fusion techniques could foster innovative solutions for such complex venous interventions and have the potential to affect a great number of patients.

Aging techniques for deep vein thrombosis: a systematic review

Deep vein thrombosis is common with an incidence of 1 in 1000. Acute thrombus removal for extensive proximal deep vein thrombosis using catheter-directed techniques highlights the need for accurate assessment of thrombus age. This systematic review summarises experimental and clinical evidence of imaging techniques for aging deep vein thrombosis. Ultrasound elastography and magnetic resonance imaging were highlighted as the most studied imaging modalities. Elastography was shown to distinguish between acute and chronic clots, despite demonstrating difficulty in accurate aging of clots older than 10 days in rat models. Elastography is noted as a feasible adjunct to current first-line imaging for deep vein thrombosis using duplex ultrasonography. Combinations of magnetic resonance imaging techniques can identify acute, sub-acute and chronic thrombi using endogenous contrast agents and provide objective standardisation of the diagnostic process, with reduced onus upon operator dependency. Further validation is required of these novel imaging techniques prior to clinical implementation for deep vein thrombosis aging.

The evaluation of lower-extremity ulcers

Lower-limb ulceration is prevalent in Western countries. There are many different types of ulcers with several causes. The most prevalent are those due to vascular disease, of which venous is the most common, accounting for over two-thirds of all types of ulcers. There are also many other causes for ulceration such as malignancy, infections, and skin, drug-induced, and autoimmune diseases. The ulcers have different characteristics, which may be differentiated by the history and clinical examination of the patients. However, objective documentation for the ulcer etiology is necessary prior to instigating treatment. The methods for diagnosing the causes for the ulcers include plethysmography, ultrasound, angiography, computer tomography, magnetic resonance imaging, and skin biopsy. All these tests should be used in conjunction with the clinical presentation of the patient. They should be performed in a cost-effective manner to avoid delays in diagnosis and reduce costs and usage of resources.

Clinical significance of recurrent venous thromboembolism

Recurrent venous thromboembolism is a significant problem leading to increased morbidity and mortality. It has a high impact on patients' quality of life and imposes a great financial burden on society. Cumulative recurrence has been reported as 40% at 10 years, while the chance of developing postthrombotic signs and symptoms in the lower extremities almost quadruples when ipsilateral. There is also a higher chance of developing pulmonary hypertension. Important factors for recurrence are unprovoked episodes of deep vein thrombosis, malignancy and older age. The evidence for other factors is controversial. Accurate diagnosis and treatment tailored to the patients' history, thrombotic events and risk factors are necessary to optimize management and prevent recurrence.

Impact and clinical significance of recurrent venous thromboembolism

Background

The purpose of this review was to analyse current knowledge and controversies associated with the diagnosis, treatment and prevention of recurrent venous thromboembolism (VTE).

Methods

MEDLINE and manual searches were performed to select prospective papers on the diagnosis, treatment and prevention of recurrent VTE for their relevance and quality.

Results

The cumulative incidence of recurrent VTE increases from 11 per cent at 1 year to 40 per cent at 10 years. The incidence of recurrence is higher in unprovoked thrombosis compared with provoked VTE. Patients with unprovoked deep vein thrombosis also have a greater number of multiple recurrences. Ultrasonography or D-dimer monitoring may have an impact on the duration of anticoagulation but further refinements are needed. The incidence of skin damage is higher in ipsilateral recurrence compared with contralateral or no recurrence. Legs with ipsilateral recurrence more often have both reflux and obstruction.

Conclusion

The role and weight of the predictive factors for recurrent VTE and its sequelae, and the type and optimal duration of anticoagulation have not been studied adequately. Fatality associated with pulmonary embolism and rates of recurrent VTE remain unacceptably high.

Imaging presentation of venous thrombosis in patients with cancer

OBJECTIVE

The purpose of this article is to review the imaging of venous thrombosis in patients with cancer.

CONCLUSION

Multiple imaging techniques have the capacity to display thrombosis accurately. The optimal choice is dictated by the location and duration of symptoms and by the availability of imaging techniques. Peripheral and superficial thrombi are best managed with ultrasound, whereas central thrombi require CT or MRI. If CT and MRI are contraindicated, flow studies are appropriate. FDG PET/CT appropriately shows venous thrombosis and might play a prominent role in the future.

Inflammation in deep vein thrombosis and the development of post-thrombotic syndrome: a prospective study

BACKGROUND

The aim of this study was to investigate whether inflammatory markers (interleukin-6 [IL-6] and C-reactive protein [CRP]) in the acute phase of deep vein thrombosis (DVT) are associated with elevated venous outflow resistance (VOR), thrombosis score (TS), reflux and the development of clinical post-thrombotic syndrome (PTS).

METHODS

In 110 patients with a first DVT, plasma concentrations of IL-6 and CRP were determined on the day of admission. VOR, TS and reflux were measured 7 days, 1 and 3 months after diagnosis. After 1 year patients were evaluated for PTS using the Clinical, Etiologic, Anatomic and Pathophysiologic (CEAP) classification and Villalta scale.

RESULTS

Median levels of IL-6 and CRP were 7 pg mL(-1) and 21 mg L(-1), respectively. After 3 months, VOR was elevated in 33 patients (30%), TS in 33 (30%) and reflux in 57 (52%). Incidence of PTS was 36.7% using CEAP>or=3 and 35.4% using Villalta-scale>or=5. Elevated levels of IL-6 and CRP were related to higher outcomes of VOR after 3 months [relative risks (RR) 2.4 (95% CI 1.5-3.9) and 1.4 (1.1-3.3), respectively] and for IL-6 to TS [1.5 (1.1-2.1)]. For reflux no relation was found. After 90 days, elevated outcomes of VOR, TS and reflux were related to PTS after 1 year. The association of IL-6 and CRP with PTS was weak using the CEAP classification with a RR of 1.2 (0.7-2.2) and 1.8 (0.9-3.3) and absent according to the Villalta scale 0.6 (0.2-1.4) and 1.2 (0.6-2.5), respectively.

CONCLUSION

The results of this study suggest that inflammation might play a role in incomplete thrombus clearance, venous outflow obstruction and the development of PTS after 1 year.

Sonographic elasticity imaging of acute and chronic deep venous thrombosis in humans

OBJECTIVE

The purpose of this study was to assess the ability of sonographic elasticity imaging to distinguish acute from chronic deep venous thrombosis (DVT).

METHODS

Fifty-four patients, 26 with acute DVT and 28 with chronic DVT, were studied, and we analyzed the data in 46 patients, 23 with acute (mean age, 5.7 days) and 23 with chronic (>8 months) DVT. Scanning was performed with a 5-MHz linear array transducer during continuous freehand external deformation of each thrombus using the ultrasound scan head. The strains in the thrombi were normalized to the average strain between the skin surface and the back wall of the vein. Relative thrombus echogenicity was measured by comparing the echogenicity of the thrombus with that of the adjacent arterial lumen. Statistical analyses were performed with the Mann-Whitney U test and receiver operating characteristic analysis.

RESULTS

The median normalized strain magnitude for the acute cases was 2.75, with an interquartile range of 2.4 to 3.71, whereas the median normalized strain magnitude for the chronic cases was 0.94, with interquartile range of 0.48 to 1.36. The difference was highly significant (P < 10(-7)). The area under the receiver operating characteristic curve (A(z)) was 0.97 +/- 0.02 (SE). The echogenicity difference between the populations was highly significant (P < 10(-5)), with A(z) of 0.92 +/- 0.04. The difference between the A(z) values was not significant (P > .05).

CONCLUSIONS

In this population, sonographic elasticity imaging performs at least as well as thrombus echogenicity. Thrombus aging using elasticity imaging would be particularly helpful in evaluating symptoms in patients with post-thrombotic syndrome.

Is True FISP Imaging Reliable in the Evaluation of Venous Thrombosis?

OBJECTIVE

The objective of our study was to evaluate the accuracy of true fast imaging with steady-state precession (FISP) in the diagnosis of venous thrombosis using gadolinium-enhanced 3D T1-weighted gradient-echo images and correlative imaging as the gold standard.

MATERIALS AND METHODS

Twenty-five MR examinations were retrospectively reviewed independently by two radiologists to rule out thrombosis in the central veins of the body. The presence of venous thrombus was assessed separately in 80 veins using true FISP and gadolinium-enhanced T1-weighted images. Diagnosis was confirmed by another imaging technique (sonography, CT, and/or conventional venography) in all positive cases. Negative examinations were confirmed using imaging, clinical follow-up, or both.

RESULTS

Venous thrombosis was present in 25 veins in 18 patients. True FISP images had a lower sensitivity (66%) and specificity (70.9%) for the diagnosis of venous thrombosis than gadolinium-enhanced MR images (p < 0.01).

CONCLUSION

True FISP images have lower sensitivity and specificity in the diagnosis of venous thrombosis than gadolinium-enhanced T1-weighted gradient-echo images. True FISP images should not be used exclusively for the diagnosis of venous thrombosis.

Advances in vascular imaging

The improvement of vascular imaging has allowed the acquisition of vascular images with higher resolution while minimizing the risks and discomfort to patients. As imaging developments continue to progress, establishment of valid clinical-based evidence, before the application of each innovation, will assure maintenance of the current trend. Also, as the vascular surgeon adopts a more comprehensive approach in the care of vascular patients, a high-quality endovascular suite will provide an environment for integration of both traditional open and evolving endovascular procedures.

MR imaging in abdominal emergencies

The use of MR imaging in the emergency setting is evolving. Clear indications include situations in need of contrast media when iodinated contrast cannot be administered or to facilitate assessments in pregnant patients and children when exposure to ionizing radiation is considered unacceptable. The availability of rapid, motion-immune sequences now makes MR imaging a feasible study in less cooperative patients extending the range of patients for whom a diagnostic study can be achieved. Capitalizing on the unique benefits of MR imaging there is optimism that MR imaging can eliminate test redundancy and impact patient care in a cost-effective manner. Further investigations are needed to identify the diagnostic algorithms for which this favorable use holds true.

Deep venous thrombosis: diagnosis by using venous enhanced subtracted peak arterial MR venography versus conventional venography

PURPOSE

To assess diagnostic accuracy and interobserver variability at venous enhanced subtracted peak arterial (VESPA) magnetic resonance (MR) venography compared with those at conventional venography for the diagnosis of femoral and iliac deep venous thrombosis (DVT).

MATERIALS AND METHODS

A single anteroposterior maximum intensity projection (MIP) venogram of the femoral and iliac veins was constructed by using VESPA MR venography in 55 symptomatic patients suspected of having lower limb DVT. All patients also underwent conventional venography, results of which were used as the standard of reference. VESPA MR venograms were interpreted by two independent reviewers (reviewers A and B) who were unaware of other results. Sensitivity and specificity of VESPA MR venography for the diagnosis of thrombus in the femoral and iliac veins were calculated. Interobserver variability was calculated for these observations by using weighted kappa with equally spaced weights for positive, nondiagnostic, and negative studies. Nondiagnostic studies were reinterpreted separately by reviewer A on the basis of source data.

RESULTS

Sensitivity of VESPA MR venography for the femoral veins (20 of 20) and iliac veins (seven of seven) was 100% for both reviewers. Specificity was 100% (39 of 39 for reviewer A, 40 of 40 for reviewer B) for the iliac veins and 97% (31 of 32) for the femoral veins for both reviewers. Segments in which the VESPA MR venograms were nondiagnostic were excluded from this analysis. Interobserver variability as calculated by using weighted kappa for positive, negative, and nondiagnostic studies was 0.85 for femoral veins and 0.97 for iliac veins. Interpretation of the source data led to correct diagnosis in six of six cases in which the VESPA MR venograms were nondiagnostic.

CONCLUSION

VESPA MR venography yielded MIP venograms that were highly accurate for the diagnosis of DVT in femoral and iliac veins. Interpretation of the studies was also highly reproducible.

Body MR venography

MRV offers unique diagnostic possibilities for detection and characterization of venous disease. It allows evaluation of perivascular and vascular anatomy, evolution of thromboembolic events, and assessment of vascular flow. MRI is a diagnostic tool that can be tailored for a variety of clinical dilemmas, not only DVTs. Continued improvements in hardware and software will expand the role of MRV.

Triplex ultrasound: elasticity imaging to age deep venous thrombosis

Deep venous thrombosis (DVT), and its sequela, pulmonary embolism (PE), is the leading cause of preventable in-hospital mortality in the USA and other developed countries. After it is detected, acute clots must be differentiated from chronic DVT for appropriate treatment. However, there are no reliable thrombus staging methods presently available in clinical practice. In this study, we tested the hypothesis that blood clots can be detected and staged using a triplex ultrasound (US) test. Triplex US is based on a "gold standard" duplex US technique augmented by US-based reconstructive elasticity imaging. Fibrin-composed blood clots harden with development and organization. By imaging clot elasticity, it may be possible to both detect and differentiate clots and, therefore, provide an urgently needed noninvasive means of DVT staging.

Inflammatory response in the acute phase of deep vein thrombosis

OBJECTIVE

Deep vein thrombosis (DVT) is a multifactorial disease. Recently, inflammation has been suggested as a risk factor for DVT. The question is whether inflammation is a cause of venous thrombosis or rather a result of the thrombotic process.

METHODS

We studied the inflammatory response in the acute phase of DVT with interleukin-6, interleukin-8, and C-reactive protein (CRP) as inflammatory markers. Plasma concentrations were measured on the day of admission (day 0) in 40 patients with acute DVT confirmed with phlebography and in 33 patients with clinical suspicion of DVT but negative phlebography results (controls). In patients with DVT, inflammatory markers were also examined on five subsequent days.

RESULTS

On day 0, the median concentrations in plasma of interleukin-6, interleukin-8, and CRP were 15.0 pg/mL (range, <3 to 70 pg/mL), 7.0 pg/mL (range, <3 to 76 pg/mL), 37.5 mg/L (range, <7 to 164 mg/L), respectively, in the patient group and less than 3 pg/mL (range, <3 to 11 pg/mL; P <.001), 6.0 pg/mL (range, <3 to 52 pg/mL; P =.08), and 5.0 pg/L (range, <7 to 66 pg/L; P <.001), respectively, in the controls. During the next days, interleukin-6 concentration showed a gradual decline in patients with DVT from 15.0 to 5.5 pg/mL (P <.001), interleukin-8 concentration was relatively constant in time, and CRP concentration declined from 37.5 to 21.5 mg/L (P =.01).

CONCLUSION

Our data show an apparent inflammatory response with highest measured concentrations of inflammatory markers on the day of admission and a subsequent decrease during the next days. This response supports the hypothesis that elevated inflammatory markers are a result rather than a cause of venous thrombosis.

Magnetic resonance venography in the diagnosis and management of May-Thurner syndrome

Isolated left lower extremity swelling secondary to left iliac vein compression was first described by McMurrich in 1908, and defined anatomically by May and Thurner in 1957 and clinically by Cockett and Thomas in 1965. The left iliac vein is usually located posterior to the right iliac artery and can be compressed between the artery and the fifth lumbar vertebrae. Symptoms include left lower extremity edema, pain, varicosities, venous stasis changes, and deep venous thrombosis. Evaluation of these patients historically included a venous duplex scan to rule out deep venous thrombosis and an abdominal computed tomography scan to rule out pelvic mass. This paper describes the use of magnetic resonance imaging and venography in the evaluation of patients with isolated left lower extremity swelling. A retrospective analysis of a series of 24 patients who presented with symptomatic left lower extremity edema was performed. Infrainguinal deep venous thrombosis and valvular reflux was evaluated by duplex scan. The presence of suprainguinal deep venous thrombosis and pelvic mass was evaluated by magnetic resonance imaging. Magnetic resonance imaging was used to define the anatomic characteristics of the May-Thurner syndrome. Patients identified with the syndrome were treated either conservatively with lower extremity compression and elevation or with angioplasty and stenting. Follow-up of this subset of patients was performed with clinical assessment of the resolution of their symptomatic lower extremity edema as well as quality of life assessments via phone interviews. Twenty-four patients were evaluated for isolated left lower extremity swelling. Seven patients had positive results on duplex scans for deep venous thrombosis. Magnetic resonance imaging results demonstrated 1/24 (4%) had a pelvic mass compressing the iliac vein; 2/24 (8%) patients had iliac vein thrombosis; 1/24 (4%) patients with a history of deep venous thrombosis demonstrated a long stenotic segment of the left iliac vein unrelated to its association with the right iliac artery; 9/24 patients (37%) had anatomic evidence of May-Thurner syndrome; and 2/24 patients (8%) had isolated left lower extremity swelling of unknown etiology. Five patients diagnosed with May-Thurner syndrome were treated conservatively with compression stockings and leg elevation. Four patients with May-Thurner syndrome underwent iliac vein angioplasty and stenting. Technical success was 100%. On clinical follow-up, the patients with May-Thurner syndrome have had improvement/resolution of their symptoms. There have been no complications from either therapy. May-Thurner syndrome is a clinical entity of left iliac vein compression by the right iliac artery, resulting in isolated left lower extremity swelling and may be a precipitating factor for iliofemoral deep venous thrombosis. Magnetic resonance imaging is the best modality for diagnosis of this entity as it can rule out the presence of pelvic masses and deep venous thrombosis while simultaneously demonstrating the anatomy characteristic of this syndrome.

Endovascular management of iliac vein compression (May-Thurner) syndrome

PURPOSE

To evaluate the feasibility of endovascular techniques in treating venous outflow obstruction resulting from compression of the iliac vein by the iliac artery of the left lower extremity (May-Thurner syndrome).

MATERIALS AND METHODS

A retrospective analysis of 39 patients (29 women, 10 men; median age, 46 years) with iliac vein compression syndrome (IVCS) was performed. Nineteen patients presented with acute deep vein thrombosis (DVT) and 20 patients presented with chronic symptoms. All patients presented with leg edema or pain. In the acute group, patients were treated with catheter-directed thrombolysis (120,000-180,000 IU urokinase/h) and angioplasty followed by stent placement. In the chronic group, patients were treated with use of angioplasty and stent placement alone (n = 8), or in combination with thrombolysis (n = 12). Patients were then followed-up with duplex ultrasound and a quality-of-life assessment.

RESULTS

Initial technical success was achieved in 34 of 39 patients (87%). The overall patency rate at 1 year was 79%. Symptomatically, 85% of patients were completely or partially improved compared with findings before treatment. Thirty-five of 39 patients received stents. The 1-year patency rate for patients with acute symptoms who received stents was 91.6%; for patients with chronic symptoms who received stents, the 1-year patency rate was 93.9%. Five technical failures occurred. Major complications included acute iliac vein rethrombosis (< 24 hours) requiring reintervention (n = 2). Minor complications included perisheath hematomas (n = 4) and minor bleeding (n = 1). There were no deaths, pulmonary embolus, cerebral hemorrhage, or major bleeding complications.

CONCLUSION

Endovascular reconstruction of occluded iliac veins secondary to IVCS (May-Thurner) appears to be safe and effective.

MR assessment of the extremity veins

This article provides an overview of the technique of magnetic resonance venography (MRV) and its relative value in the diagnostic work-up of suspected lower or upper extremity venous thrombosis. MRV is accurate for diagnosis or exclusion of deep vein thrombosis. MRV should be considered complimentary, in many instances, to the less expensive modality of venous sonography. It is the complimentary use of magnetic resonance techniques at the level of the pelvis and the mediastinum that offers the greatest cost benefit as part of an incremental strategy for the work-up of patients presenting with lower or upper extremity swelling.