Systematic review and meta-analysis of the diagnostic accuracy of ultrasonography for deep vein thrombosis

Imaging of Deep Venous Pathology

Imaging plays an important role in the identification and assessment of clinically suspected venous pathology. The purpose of this article is to review the spectrum of image-based diagnostic tools used in the investigation of suspected deep vein disease, both obstructive (deep vein thrombosis and post-thrombotic vein changes) as well as insufficiency (e.g., compression syndromes and pelvic venous insufficiency). Additionally, specific imaging modalities are used for the treatment and during clinical follow-up. The use of duplex ultrasound, magnetic resonance venography, computed tomography venography and intravascular ultrasound as well as conventional venography will be discussed in this pictorial review.

Noninvasive and invasive imaging of lower-extremity acute and chronic venous thrombotic disease

The spectrum of venous thromboembolic (VTE) disease encompasses both acute deep venous thrombosis (DVT) and chronic postthrombotic changes (CPC). A large percentage of acute DVT patients experience recurrent VTE despite adequate anticoagulation, and may progress to CPC. Further, the role of iliocaval venous obstruction (ICVO) in lower-extremity VTE has been increasingly recognized in recent years. Imaging continues to play an important role in both acute and chronic venous disease. Venous duplex ultrasound remains the gold standard for diagnosing acute VTE. However, imaging of CPC is more complex and may involve computed tomography, magnetic resonance, contrast-enhanced ultrasound, or intravascular ultrasound. In this narrative review, we aim to discuss the full spectrum of venous disease imaging for both acute and chronic venous thrombotic disease.

Analysis of risk factors for postoperative deep vein thrombosis after craniotomy and nomogram model construction

BACKGROUND

Deep vein thrombosis (DVT) of the lower extremity is one of the most common postoperative complications, especially after craniocerebral surgery. DVT may lead to pulmonary embolism, which has a devastating impact on patient prognosis. This study aimed to investigate the incidence and risk factors of DVT in the lower limbs following craniocerebral surgery.

AIM

To identify independent risk factors for the development of postoperative DVT and to develop an effective risk prediction model.

METHODS

The demographic and clinical data of 283 patients who underwent craniocerebral surgery between December 2021 and December 2022 were retrospectively analyzed. The independent risk factors for lower extremity DVT were identified by univariate and multivariate analyses. A nomogram was created to predict the likelihood of lower extremity DVT in patients who had undergone craniocerebral surgery. The efficacy of the prediction model was determined by receiver operating characteristic curve using the probability of lower extremity DVT for each sample.

RESULTS

Among all patients included in the analysis, 47.7% developed lower extremity DVT following craniocerebral surgery. The risk of postoperative DVT was higher in those with a longer operative time, and patients with intraoperative intermittent pneumatic compression were less likely to develop postoperative DVT.

CONCLUSION

The incidence of lower extremity DVT following craniocerebral surgery is significant, highlighting the importance of identifying independent risk factors. Interventions such as the use of intermittent pneumatic compression during surgery may prevent the formation of postoperative DVT.

Common Iliac Artery Mycotic Pseudoaneurysm Associated with a Prevertebral Infection: A Case Report

Introduction

Mycotic pseudoaneurysms are rare but severe sequelae of an arterial wall infection. If undiagnosed and untreated they can lead to significant morbidity and mortality through complications such as arterial rupture or dissection.

Case report

This report details the case of a 64-year-old-male who developed a left common iliac artery mycotic pseudoaneurysm from Proteus mirabilis, which was associated with a prevertebral abscess. The patient presented with isolated, left lower extremity edema and intermittent fevers. The case is unique in both the pathogen (P mirabilis) and in its association with presumed direct arterial wall infection from an adjacent prevertebral abscess.

Conclusion

The obscure presentation highlights the need for a high clinical suspicion of such a diagnosis when a patient presents with a certain constellation of symptoms and the right predisposing risk factors in their history.

Factors associated with perioperative deep vein thrombosis in arthroscopic anterior cruciate ligament reconstruction

BACKGROUND

Anterior cruciate ligament reconstruction (ACLR) is reportedly associated with a higher incidence of deep vein thrombosis (DVT) incidence than other arthroscopic surgical procedures. The aim of this study is to retrospectively investigate the incidence and type of DVT and evaluate the relationship between DVT and risk factors among all patients who underwent ACLR under uniform conditions consisting of mechanical prophylaxis, no medical prophylaxis, and preoperative and postoperative lower extremity venous ultrasonography.

METHODS

Of the 114 patients who underwent arthroscopic primary ACLR at our hospital who did not have a compound ligament injury or revision surgery, 112 patients were included. Two patients were not examined. DVT evaluation consisted of whole-leg ultrasonography at 1 week after surgery. We evaluated age, sex, body mass index, comorbidities, operative time, tourniquet time, presence of concurrent surgery (meniscus repair/resection or osteochondral column grafting), and non-weight-bearing status at 1 week after surgery as risk factors for DVT.

RESULTS

DVT was found in 33 (29.5%) of 112 patients. Of these, 22 (19.6%) had distal DVT and 11 (9.8%) had proximal DVT. Non-weight-bearing status at 1 week after surgery was a statistically significant risk factor for proximal DVT (P = .034).

CONCLUSIONS

Non-weight-bearing status is an independent risk factor for DVT, suggesting that early weight bearing may reduce the occurrence of DVT.

An Overview of Clinical Examinations in the Evaluation and Assessment of Arterial and Venous Insufficiency Wounds

Arterial and venous insufficiency are two major causes of chronic wounds with different etiology, pathophysiology, and clinical manifestations. With recent advancements in clinical examination, clinicians are able to obtain an accurate diagnosis of the underlying disease, which plays an important role in the treatment planning and management of patients. Arterial ulcers are mainly caused by peripheral artery diseases (PADs), which are traditionally examined by physical examination and non-invasive arterial Doppler studies. However, advanced imaging modalities, such as computed tomography angiography (CTA) and indocyanine green (ICG) angiography, have become important studies as part of a comprehensive diagnostic process. On the other hand, chronic wounds caused by venous insufficiency are mainly evaluated by duplex ultrasonography and venography. Several scoring systems, including Clinical-Etiology-Anatomy-Pathophysiology (CEAP) classification, the Venous Clinical Severity Score (VCSS), the Venous Disability Score, and the Venous Segmental Disease Score (VSDS) are useful in defining disease progression. In this review, we provide a comprehensive overlook of the most widely used and available clinical examinations for arterial and venous insufficiency wounds.

Prevalence of preoperative deep vein thrombosis in long bone fractures of lower limbs: a systematic review and meta-analysis

BACKGROUND

There is a paucity of data regarding the prevalence of preoperative deep vein thrombosis (DVT) in patients with long bone (including femur, tibia and fibula) fractures of the lower limbs. We performed a meta-analysis to address the issue.

METHODS

Electronic databases, including PubMed, EMBASE, the Web of Science, the Cochrane Library, the VIP database, CNKI, and the Wanfang database, were systematic searched for original articles that reported the prevalence of preoperative DVT in long bone fractures of the lower limbs from January 2016 to September 2021. The prevalence of preoperative DVT was pooled using random-effects models, and subgroups were established according to study type, detection method, sample size and fracture site.

RESULTS

Twenty-three articles reporting on 18,119 patients were eligible. The overall pooled preoperative DVT prevalence was 24.1% (95% CI 19.3-28.8%). In different subgroups, the preoperative DVT prevalences were 18.2-27.3%, 15.2-28.6%, 23.1-24.9%, 18.2-26.0% and 23.2-23.4% for different study designs, sample sizes, age groups, detection methods and fracture sites, respectively.

CONCLUSIONS

Despite the heterogeneity among studies, this systematic review suggests that the prevalence of preoperative DVT, which may seriously affect the prognosis of patients, is high. Therefore, greater efforts should be devoted to the improvement of screening and prevention strategies for preoperative DVT in lower-extremity long bone fractures.

LEVEL OF EVIDENCE

Level III. Trial Registration The study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) database with the registration number CRD42022324706.

A prospective study to evaluate the use of surveillance venous ultrasonography to detect incidence of deep venous thrombosis following neurosurgical excision of brain tumors

Objectives

Patients with brain tumors are prone to develop deep venous thrombosis (DVT) following neurosurgical excision of tumor. However, there is a deficiency of knowledge about the screening method, optimum frequency, and duration of the surveillance to diagnose DVT in the post-operative period. The primary objective was to find the incidence of DVT and associated risk factors. The secondary objectives were to find the optimum duration and frequency of surveillance venous ultrasonography (V-USG) in patients undergoing neurosurgery.

Materials and Methods

Hundred consecutive adult patients undergoing neurosurgical excision of brain tumors were included after their consent, over a period of 2 years. The risk factors for DVT were assessed in all the patients preoperatively. All patients underwent surveillance duplex V-USG of the upper and lower limbs at pre-planned time intervals in the perioperative period, by experienced radiologists and anesthesiologists. The occurrence of DVT was noted using the objective criteria. The association between the perioperative variables and the incidence of DVT was assessed using univariate logistic regression analysis.

Results

The most common prevalent risk factors were - malignancy (97%), major surgery (100%), and age >40 years (30%). Asymptomatic DVT was detected in the right femoral vein in one patient who underwent suboccipital craniotomy for high-grade medulloblastoma, on the 4th and 9th postoperative day, making the incidence of DVT 1%. The study found no association with perioperative risk factors and could not suggest the optimum duration and frequency of surveillance V-USG.

Conclusion

A low incidence of DVT (1%) was detected in patients undergoing neurosurgeries for brain tumors. Prevalent thromboprophylaxis practices and a shorter period of post-operative surveillance could be the reasons for the low incidence of DVT.

[Diagnosis of chronic venous insufficiency]

For the treatment of chronic venous insufficiency (CVI), various therapeutic options are available. In addition to conservative compression therapy, classical vein surgery, sclerotherapy and endoluminal therapies are increasingly being used to treat varicose veins. For a differentiated indication and correct treatment planning, a stepwise diagnosis with clinical examination and documentation of typical symptoms, dynamic vein function measurement to assess the global venous status as well as a qualitative assessment of the exact insufficient vein segments by means of color-coded duplex sonography is required. Due to the non-invasiveness of the examination and the good assessability of therapeutically relevant parameters such as anatomic conditions, diameter, and reflux of insufficient veins, color-coded duplex sonography is considered the gold standard for imaging diagnostics.

Pathophysiology, risk, diagnosis, and management of venous thrombosis in space: where are we now?

The recent incidental discovery of an asymptomatic venous thrombosis (VT) in the internal jugular vein of an astronaut on the International Space Station prompted a necessary, immediate response from the space medicine community. The European Space Agency formed a topical team to review the pathophysiology, risk and clinical presentation of venous thrombosis and the evaluation of its prevention, diagnosis, mitigation, and management strategies in spaceflight. In this article, we discuss the findings of the ESA VT Topical Team over its 2-year term, report the key gaps as we see them in the above areas which are hindering understanding VT in space. We provide research recommendations in a stepwise manner that build upon existing resources, and highlight the initial steps required to enable further evaluation of this newly identified pertinent medical risk.

Patterns of superficial antecubital veins observed by near-infrared light technique: A community-based study

<b>Background: </b>The area of the cubital fossa contains the main superficial veins, including the basilic, cephalic, median cubital, and median antebrachial veins, and their innominate small tributaries. For this reason, it is the area most preferred by medical practitioners to access the circulatory system for various clinical applications.<br /> <b>Objective:</b> The aim of this study was to address the prevalence of different types of antecubital fossa superficial vein patterns observable among Saudi subjects by applying a tourniquet and using a VeinViewer®.<br /> <b>Materials and methods:</b><b> </b>Over the period from September 2020 to April 2021, a cross-sectional study was carried out in the Eastern Province of Saudi Arabia. The 151 study subjects were randomly chosen from the emergency department of King Fahad University Hospital. A total of 302 venous patterns were obtained; 55 were excluded due to the presence of scar tissues over the antecubital fossa, obesity, or thick subcutaneous tissue. Four classes of cubital venous patterns were established according to other studies, and a VeinViewer® and a tourniquet were used to visualize the venous patterns.<br /> <b>Results: </b>Of the 151 people, 21 were female and 130 were male. Among the included 247 venous patterns, the predominant type was type 2 (52.2%), characterized by a branching off the median cubital vein from the cephalic vein and an upward progression to join the basilic vein.<br /> <b>Conclusion: </b>Type 2 appears to be the dominant pattern, with no significant relation to the origins of the parents, in the Saudi population. Gender does not influence the venous patterns. Further studies are needed outside the restrictions of the COVID-19 pandemic to obtain a larger sample.

Deep vein thrombosis - the role of ultrasound in the diagnosis and follow-up of patients

Deep vein thrombosis still represents a challenge regarding the diagnostics, treatment and follow-up. All this steps are often performed in the internal medicine ambulatory centers and such clinics therefore need to be aable to manage the whole process. Its key part is vascular sonography, which is needed to establish the diagnosis, the form of thrombosis and proper treatment course. There are two types of vascular sonography - Point of Care a expert sonography, being performed in two different regimes (diagnostic and follow up sonography). There are different demands for each of these two types, and each type is performed by physicians with different level of expertise. There are well defined criteria for performance a conclusions made for each type, and their precise fulfillment leads to establishment of diagnosis of DVT, early treatment initiation and setting of optimal strategy following the baseline treatment period.

ClotTriever system for mechanical thrombectomy of deep vein thrombosis

There is increasing evidence that early and comprehensive removal of thrombus in deep vein thrombosis is associated with improved outcomes, including decreased incidence of post-thrombotic syndrome and debilitating long-term symptoms. Catheter-directed thrombolysis is effective for the rapid removal of clot, but it is associated with high bleeding risk. Percutaneous mechanical thrombectomy is a highly effective method for the removal of clot without the use of systemic or catheter-directed thrombolytic therapy. The Inari ClotTriever system (Inari Medical Inc., CA, USA) is a thrombectomy device, which is approved for deep vein thrombosis by the US FDA in 2017. Herein we review the current treatment strategies using the ClotTriever system, its specifications, indications and current state of literature.

The impact of pre-existing venous pathology on lower limb free flap reconstruction and the role of preoperative screening: a systematic review

Lower limb reconstruction is performed to replace like with like and achieve tissue durability. Free flaps are a method of reconstruction commonly used to manage cases of lower limb deficits. However, the failure rate is 8.5%, with venous thrombosis and congestion playing a significant role. Despite this, preoperative venous mapping of recipient site before free flap reconstruction is not routinely practiced, often resulting in pathologies remaining unidentified until the intraoperative stage. The aim of the review was to evaluate the existing literature on the topic of lower limb preoperative venous assessment, screening, and its effect on lower limb free flap survival. Five different databases were searched from their inception to August 2021. The search terms and included studies were independently reviewed by two investigators for their eligibility. Eleven articles were eligible for inclusion, with a combined patient population of 99, and 107 flaps were identified to have lower limb pathology at the donor or recipient vein. Venous pathology was detected preoperatively in 69 veins using ultrasound duplex scanning and computed tomography angiography; of them, 3 (4.34%) resulted in failure. In comparison, 38 veins were diagnosed with venous pathology intraoperatively; of them, 5 (13.85%) failed. The studies evaluated in this review demonstrated that preoperative screening for venous pathology showed a higher flap survival rate. It can therefore be inferred that developing a standardized preoperative process for identifying venous issues in lower limb free flap reconstruction may improve outcomes. This can be explored in future research, with a focus on assessing the validity and efficacy of such screening tools, and their role in the management of patients identified with venous pathology.

Direct oral anticoagulants decrease treatment failure for acute lower extremity deep venous thrombosis

OBJECTIVE

Optimal medical therapy for acute lower extremity deep venous thrombosis (DVT) remains an enigma. While clinical trials demonstrate non-inferiority with an oral anti-Xa inhibitor, or direct oral anticoagulant (DOAC), versus combined low-molecular weight heparin (LMWH) and oral vitamin K antagonist (VKA), the most effective regimen remains to be determined.

METHODS

This study is a single-center retrospective cohort study from October 2014 to December 2015 of patients with a diagnosis of acute DVT and subsequent serial lower extremity venous duplex. Demographics, medical history, medications, serial ultrasound findings, as well as the primary anticoagulant used for treatment were collected and analyzed by two independent data extractors. Treatment failure was defined as any new DVT or progression of an existing DVT within 3 months of diagnosis of the index clot. Risk factors for treatment failure were assessed using standard odds ratios and Fischer's exact test.

RESULTS

Among 496 patients with an acute lower extremity DVT, 54% (n = 266) were men, mean age was 61 years, 35% (n = 174) involved the popliteal or more proximal segments, and 442 had documentation of the primary treatment for DVT: 20% (n = 90) received nothing; 20% (n = 92) received an oral VKA; 34% (n = 149) received a DOAC; 20% (n = 90) received LMWH; and 5% (n = 21) received another class of anticoagulant. Within 3 months, 21% (n=89 out of 427) had treatment failure defined as any new DVT or progression of prior DVT. Patients treated with a DOAC were less likely to experience treatment failure when compared with any other treatment (odds ratio 0.43; 95% confidence intervals [0.23, 0.79]; p = 0.0069) and when compared with traditional oral VKA (OR 0.44; 95% CI [0.21, 0.92]; p = 0.029). None of prior history of DVT, pulmonary embolism, thrombophilia, renal insufficiency, hepatic insufficiency, cancer, or antiplatelet therapy correlated with treatment failure. Treatment outcome did not correlate with being on any anticoagulation versus none (p = 0.74), nor did it correlate with the duration of treatment (<3 months versus ≥3 months) (p = 0.42). Proximal and distal DVTs showed no difference in treatment failure (19% versus 22%, respectively; p = 0.43).

CONCLUSION

In summary, the use of a DOAC for acute lower extremity DVT yielded better overall outcomes and fewer treatment failures at 3 months as compared to traditional oral VKA therapy based on serial duplex imaging.

Diagnosis of Internal Jugular Vein Septic Thrombophlebitis by Point-of-Care Ultrasound

ABSTRACT

Septic thrombophlebitis represents a rare but serious collection of diseases, which carry a high risk of morbidity and mortality requiring prompt and aggressive treatment. Diagnosis centers on identification of thrombus along with clinical and microbiologic data. We present a case where point-of-care ultrasound was used to diagnose septic thrombophlebitis of the internal jugular vein and expedite appropriate therapy. We further review the technique and literature for ultrasound diagnosis of venous thrombosis and associated thrombophlebitis.

Deep vein thrombosis in donor or recipient veins encountered during lower extremity reconstruction with a free anterolateral thigh perforator flap: How do we deal with it?

Background

The free anterolateral thigh perforator (ALTP) flap has been successfully adopted to reconstruct traumatic soft tissue defects in the lower extremities. However, the occurrence of deep vein thrombosis (DVT) in donor or recipient veins has been overlooked, and there has been no reliable guideline to manage it. Therefore, in this study, we review our cases where the ALTP flaps were transferred to traumatic lower limbs even though DVT was found in the pedicle or recipient veins. Furthermore, based on our experiences, we suggest an algorithmic approach for dealing with DVT.

Patients and methods

This study included 108 patients who underwent lower extremity reconstruction using a free ALTP flap between January 2014 and January 2021. All medical records were reviewed, including preoperative assessment data, intraoperative findings, and postoperative complications. Notably, when DVT was found in both the donor and recipient veins, we thoroughly assessed operative findings, surgical solutions, and final outcomes.

Results

Sixty-one of 108 (56.4%) patients underwent computed tomographic venography (CTV) preoperatively, revealing DVT in 11 of these 61 (18%) patients. Three of these 11 patients had iliofemoral DVT, and surgery was delayed more than two weeks after detection. The remaining eight patients had calf DVT and underwent free ALTP flap transfer as scheduled. Conversely, 47 of 108 (43.6%) patients did not undergo CTV, and an occult DVT was found in five of these 47 (10.6%) patients. In two of these five patients, free flap surgery was replaced with amputation and local flap coverage. In the remaining three patients and one patient with an occult DVT that was not found on CTV, the free ALTP flap transfer was carried out. In 15 patients with DVT, free ALTP flap transfer was performed using various alternative methods for venorrhaphy. Consequently, all flaps survived, with partial necrosis occurring in two patients.

Conclusion

If DVT-affected veins are appropriately managed, the free ALTP flap can be successfully transferred to the traumatic lower limb even when DVT occurs in donor or recipient veins. The author's algorithm can help surgeons overcome the insufficiency of veins for pedicle anastomosis due to DVT and avoid postoperative thromboembolic complications.

Diagnosis of venous thromboembolism in pregnancy: a review of current guidelines

Venous thromboembolic disease (VTE) is the leading cause of maternal death throughout the developed world. International and national guidance for the diagnosis and management of VTE in pregnancy is varied and limited, which can result in problems in clinical practice. The imaging challenges of VTE in the general population are challenging but become more complex in pregnancy due to the physiological changes in the circulatory system, which alter clinical judgment and test performance. As an additional factor, the relative radiation risks to the mother and fetus arising from diagnostic tests need to be assessed and communicated to the patient in a clear and understandable way. The purpose of this review is fourfold. We propose to review and summarise the current imaging guidelines available for this condition; critically review the evidence base within the current literature; address the issues of test performance of imaging examinations used for VTE in pregnancy; and address the question of radiation risk and how to communicate this information to patients.

Interventions for preventing venous thromboembolism in adults undergoing knee arthroscopy

BACKGROUND

Knee arthroscopy (KA) is a routine orthopedic procedure recommended to repair cruciate ligaments and meniscus injuries and, in suitable cases, to assist the diagnosis of persistent knee pain. There is a small risk of thromboembolic events associated with KA. This systematic review aims to assess if pharmacological or non-pharmacological interventions may reduce this risk. This is an update of an earlier Cochrane Review.

OBJECTIVES

To evaluate the efficacy and safety of interventions - whether mechanical, pharmacological, or a combination of both - for thromboprophylaxis in adults undergoing KA.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 1 June 2021.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and controlled clinical trials (CCTs), blinded or unblinded, of all types of interventions used to prevent deep vein thrombosis (DVT) in men and women aged 18 years and older undergoing KA.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were pulmonary embolism (PE), symptomatic DVT, asymptomatic DVT, and all-cause mortality. Our secondary outcomes were adverse effects, major bleeding, and minor bleeding. We used GRADE criteria to assess the certainty of the evidence.

MAIN RESULTS

We did not identify any new studies for this update. This review includes eight studies involving 3818 adults with no history of thromboembolic disease. Five studies compared daily subcutaneous low-molecular-weight heparin (LMWH) versus no prophylaxis; one study compared oral rivaroxaban 10 mg versus placebo; one study compared daily subcutaneous LMWH versus graduated compression stockings; and one study compared aspirin versus no prophylaxis. The incidence of PE in all studies combined was low, with seven cases in 3818 participants. There were no deaths in any of the intervention or control groups. Low-molecular-weight heparin versus no prophylaxis When compared with no prophylaxis, LMWH probably results in little to no difference in the incidence of PE in people undergoing KA (risk ratio [RR] 1.81, 95% confidence interval [CI] 0.49 to 6.65; 3 studies, 1820 participants; moderate-certainty evidence). LMWH may make little or no difference to the incidence of symptomatic DVT (RR 0.61, 95% CI 0.18 to 2.03; 4 studies, 1848 participants; low-certainty evidence). It is uncertain whether LMWH reduces the risk of asymptomatic DVT (RR 0.14, 95% CI 0.03 to 0.61; 2 studies, 369 participants; very low-certainty evidence). LMWH probably makes little or no difference to the risk of all adverse effects combined (RR 1.85, 95% CI 0.95 to 3.59; 5 studies, 1978 participants; moderate-certainty evidence), major bleeding (RR 0.98, 95% CI 0.06 to 15.72; 1451 participants; moderate-certainty evidence), or minor bleeding (RR 1.79, 95% CI 0.84 to 3.84; 5 studies, 1978 participants; moderate-certainty evidence). Rivaroxaban versus placebo One study with 234 participants compared oral rivaroxaban 10 mg versus placebo. There were no cases of PE reported. Rivaroxaban probably led to little or no difference in symptomatic DVT (RR 0.16, 95% CI 0.02 to 1.29; moderate-certainty evidence). It is uncertain whether rivaroxaban reduces the risk of asymptomatic DVT because the certainty of the evidence is very low (RR 0.95, 95% CI 0.06 to 15.01). The study only reported bleeding adverse effects. No major bleeds occurred in either group, and rivaroxaban probably made little or no difference to minor bleeding (RR 0.63, 95% CI 0.18 to 2.19; moderate-certainty evidence). Aspirin versus no prophylaxis One study compared aspirin with no prophylaxis. There were no PE, DVT or asymptomatic events detected in either group. The study authors reported adverse effects including pain and swelling, but without clarifying which groups these occurred in. There were no bleeds reported. Low-molecular-weight heparin versus compression stockings One study with 1317 participants compared LMWH versus compression stockings. LMWH may lead to little or no difference in the risk of PE compared to compression stockings (RR 1.00, 95% CI 0.14 to 7.05; low-certainty evidence), but it may reduce the risk of symptomatic DVT (RR 0.17, 95% CI 0.04 to 0.75; low-certainty evidence). It is uncertain whether LMWH has any effect on asymptomatic DVT (RR 0.47, 95% CI 0.21 to 1.09; very low-certainty evidence). The results suggest LMWH probably leads to little or no difference in major bleeding (RR 3.01, 95% CI 0.61 to 14.88; moderate-certainty evidence), or minor bleeding (RR 1.16, 95% CI 0.64 to 2.08; moderate-certainty evidence). We downgraded the certainty of the evidence for imprecision due to overall small event numbers, for risk of bias due to concerns about lack of blinding, and for indirectness due to uncertainty about the direct clinical relevance of asymptomatic DVT detection.

AUTHORS' CONCLUSIONS

There is a small risk that healthy adults undergoing KA will develop venous thromboembolism (PE or DVT). We found moderate- to low-certainty evidence of little or no benefit from LMWH, or rivaroxaban in reducing this small risk of PE or symptomatic DVT. The studies provided very low-certainty evidence that LMWH may reduce the risk of asymptomatic DVT compared to no prophylaxis, but it is uncertain how this directly relates to incidence of DVT or PE in healthy people undergoing KA. There is probably little or no difference in adverse effects (including major and minor bleeding), but data relating to these outcomes were limited by low numbers of events in the studies reporting these outcomes.

VENOUS THROMBOEMBOLISM IN THE EMERGENCY DEPARTMENT - SINGLE-CENTER EXPERIENCE

Given the importance of early recognition of acute venous thromboembolism (VTE) and the nonspecificity of its symptoms and signs, it is essential to follow the guidelines for diagnostic and therapeutic decisions. Ultrasound examination of the entire lower extremity is currently the standard diagnostic method for symptomatic patients with a clinical probability of deep vein thrombosis (DVT) according to the Wells scoring system. The aim of this study is to show the demographic structure and analyze the number of patients in the emergency department with suspected venous thrombosis. In the past 10 years, 2,022 patients with DVT and 686 with pulmonary emboli have been diagnosed. Despite adherence to the diagnostic protocol, nearly two-thirds of patients require early ultrasound diagnosis. One-fifth of patients had thrombosis of the superficial venous system of the leg or arm. Thrombus was present in the veins of the lower leg in 37% of patients with DVT. The presence of thrombi above the knee, involving the deep femoropopliteal venous system, was found in as much as one-third of patients. These findings and current guidelines suggest that there is a paradigm shift toward more frequent use of DOAC in patients with DVT. However, greater educational efforts may be needed for many physicians to become comfortable with the use of DOAC in the outpatient management of patient populations at low risk for pulmonary embolism.

Prevalence and risk factor of post-operative lower extremities deep vein thrombosis in patients undergoing gynecologic surgery: a single-institute cross-sectional study

Background and aim

The study of prevalence and risk factors of postoperative lower limb deep vein thrombosis (DVT) in Thai gynecologic patients was limited. The present study was conducted to evaluate this issue.

Methods

The patients were age > 15 years old without a history of DVT or pulmonary emboli (PE) scheduled for laparotomy or vaginal gynecologic surgery between May and November 2020 were invited to participate. All of these patients were scheduled for a complete duplex ultrasound to detect lower limb DVT 72 h before and within 14 days after the operation. The patients without DVT were scheduled for an interview by telephone about DVT symptoms 30 days after the operation. The clinical variables were compared using univariate and multivariate analysis to identify the independent factors related to the development of DVT.

Results

One hundred and twelve patients met the inclusion criteria. Of these patients, 44 cases (39.3%) were diagnosed as malignancy and 102 patients underwent a hysterectomy. Post-operative DVTs were detected in six patients (5.4%) and all except one had a malignancy. Thus, the prevalence of DVT in malignancy cases was five in 44 patients (11.4%). The independent risk factors for postoperative DVT were age > 60-year-old and receiving a perioperative blood transfusion. Five of six DVT patients received low molecular-weight heparin for treatment of DVT and none developed PE. The rest of the participants reported no symptom-related DVTs from the interview 30 days after the operation.

Conclusion

The prevalence of postoperative DVT in gynecologic patients was 5%, and the independent risk factors were elderly patients and receiving a perioperative blood transfusion.

Clinical impact of assessing thrombus age using magnetic resonance venography prior to catheter-directed thrombolysis

Objectives

Magnetic resonance venography (MRV) is underutilized in the evaluation of thrombus properties prior to endovascular treatment but may improve procedural outcomes. We therefore investigated the clinical impact of using a dedicated MRV scoring system to assess thrombus characteristics prior to endovascular intervention for iliofemoral deep vein thrombosis (DVT).

Methods

This is a post hoc analysis of data from the CAVA trial (Clinicaltrials.gov:NCT00970619). MRV studies of patients receiving ultrasound-accelerated catheter-directed thrombolysis (CDT) for iliofemoral DVT were reviewed. Thrombus age-related imaging characteristics were scored and translated into an overall score (acute, subacute, or old). MRV scores were compared to patient-reported complaints. MRV-scored groups were compared for CDT duration and success rate.

Results

Fifty-six patients (29 men; age 50.8 ± 16.4 years) were included. Using MRV, 27 thrombi were classified acute, 17 subacute, and 12 old. Based on patient-reported complaints, 11 (91.7%) of these old thrombi would have been categorized acute or subacute, and one (3.7%) of the acute thrombi as old. Average duration of CDT to > 90% restored patency differed significantly between groups (p < 0.0001): average duration was 23 h for acute thromboses (range: 19–25), 43 h for subacute (range: 41–62), and 85 h for old thromboses (range: 74–96). CDT was almost eleven times more successful in thromboses characterized as acute and subacute compared to old thromboses (OR: 10.7; 95% CI 2.1–55.5).

Conclusion

A dedicated MRV scoring system can safely discriminate between acute, subacute, and old thromboses. MRV-based selection is predictive of procedural duration and success rate and can help avoid unnecessary complications.

Key Points

• Thrombus age, characterized by MRV as acute, subacute, and old, can predict CDT duration and probability of success.

• Accurate pre-interventional MRV-based thrombus aging has the potential to facilitate identification of eligible patients and may thus prevent CDT-related complications.

Ultrasound Imaging of Superficial Venous Thrombosis in the Upper and Lower Extremities: Closing the Gap Between Clinical Management Guidelines and Ultrasound Practice Parameters

Superficial venous thrombosis (SVT) of the upper and lower extremities has long been considered a relatively benign condition. But in recent years, the literature has suggested a benefit to anticoagulation in patients with certain thrombus characteristics (size, location, and distance to deep venous system) resulting in updates to clinical guidelines for the treatment of lower extremity SVT. Despite these now well-established guidelines, there remains a paucity of guidance from national and international societies regarding the imaging of superficial veins when evaluating for venous thrombosis. We recommend potential strategies to close this gap.

Diagnosis of deep vein thrombosis with D-dimer adjusted to clinical probability: prospective diagnostic management study

Objective

To evaluate the safety and efficiency of a diagnostic algorithm for deep vein thrombosis (DVT) that uses clinical pretest probability based D-dimer thresholds to exclude DVT.

Design

Prospective diagnostic management study.

Setting

University based emergency departments or outpatient clinics in Canada.

Participants

Patients with symptoms or signs of DVT.

Intervention

DVT was considered excluded without further testing by Wells low clinical pretest probability and D-dimer <1000 ng/mL or Wells moderate clinical pretest probability and D-dimer <500 ng/mL. All other patients had proximal ultrasound imaging. Repeat proximal ultrasonography was restricted to patients with initially negative ultrasonography, low or moderate clinical pretest probability, and D-dimer >3000 ng/mL or high clinical pretest probability and D-dimer >1500 ng/mL. If DVT was not diagnosed, patients did not receive anticoagulant treatment.

Main outcome measure

Symptomatic venous thromboembolism at three months.

Results

1508 patients were enrolled and analysed, of whom 173 (11.5%) had DVT on scheduled diagnostic testing. Of the 1275 patients with no proximal DVT on scheduled testing who did not receive anticoagulant treatment, eight (0.6%, 95% confidence interval 0.3% to 1.2%) were found to have venous thromboembolism during follow-up. Compared with a traditional DVT testing strategy, this diagnostic approach reduced the need for ultrasonography from a mean of 1.36 scans/patient to 0.72 scans/patient (difference −0.64, 95% confidence interval −0.68 to −0.60), corresponding to a relative reduction of 47%.

Conclusions

The diagnostic strategy using a combination of clinical pretest probability and D-dimer identified a group of patients at low risk for DVT during follow-up while substantially reducing the need for ultrasound imaging.

Registration

ClinicalTrials.gov NCT02038530.

Deep vein thrombosis after major orthopedic surgery in Taiwan: A prospective cross-sectional study and literature review

BACKGROUND/PURPOSE

Postoperative venous thromboembolism is an important complication in Taiwan. We prospectively investigated the occurrence of deep vein thrombosis (DVT) after major orthopedic surgery without pharmacologic thromboprophylaxis in a cohort of 120 patients (46 males, 74 females, median age 71 years) at our institute.

METHODS

Color duplex compression ultrasonography (CUS) was used to detect DVT before and after the operation, while contrast venography was performed postoperatively for comparison and validation.

RESULTS

Total knee arthroplasty (TKA, 57 cases) and total hip arthroplasty (23 cases) were the most commonly performed operations. The rate of postoperative DVT was 7.5% (9/120), including five with proximal DVT and four with distal DVT. All were detected in the limbs on the operated side. Four of them were symptomatic DVT cases. Venography was performed in 19 patients and confirmed most findings of CUS, indicating the effectiveness of CUS for detecting DVT. The type of surgery (TKA) was significantly correlated with postoperative DVT. No clinically symptomatic pulmonary embolism or sudden death events were noted.

CONCLUSION

Nine out of 120 (7.5%) orthopedic patients without pharmacologic thromboprophylaxis developed postoperative sonographic DVT in our study. The DVT rate is consistent with other reports from various Asian countries and evidence from meta-analyses.

Vascular Imaging in the Asymptomatic High-risk Cancer Population: A Role for Thrombosis Screening and Therapy Management

OBJECTIVES

We retrospectively examined the venous thromboembolism (VTE) events diagnosed in the Prophylaxis of High-Risk Ambulatory Cancer Patients Study (PHACS), a multi-center randomized trial, to assess the value of screening vascular imaging for the diagnosis of incidental VTE in high-risk cancer patients.

METHODS

A total of 117 asymptomatic cancer patients with a Khorana score ≥3 starting a new systemic chemotherapy regimen were enrolled in a prospective randomized control trial. Patients underwent baseline venous ultrasound (US) of the lower extremities (LEs) and screening contrast-enhanced chest computed tomography (CT). Those without preexisting VTE were then randomized into observation or dalteparin prophylaxis groups and were screened with serial US every 4 weeks for up to 12 weeks and imaged with contrast-enhanced chest CT at 12 weeks. Any additional imaging performed during the study period was also evaluated for VTE.

RESULTS

Baseline prevalence of incidental VTE was 9% (n = 10) with 58% percent of VTEs diagnosed by screening US. Incidence of VTE in the randomized phase of the trial was 16% (n = 16) with 21% (n = 10) of patients in the control arm and 12% (n = 6) of patients in the dalteparin arm developing VTE, a non-significant 9% absolute risk reduction (HR = 0.69, 95% CI 0.23-1.89). Sixty-nine percent of these patients were asymptomatic with 31% of patients diagnosed by screening US.

CONCLUSIONS

Adding screening US to routine oncologic surveillance CT in high-risk ambulatory cancer patients with a Khorana score ≥3 can lead to increased VTE detection, with potential for decreased morbidity, mortality, and health care spending.

Two Cases of Extensive Venous Thrombosis Incidentally Discovered With Bedside Ultrasound for Intravenous Access

Perioperative deep vein thrombosis (DVT) is a serious and increasingly common complication. While point-of-care ultrasound is commonly used in regional nerve blocks, central vascular access, and difficult peripheral vascular, access there are very few reports of DVT incidentally discovered by anesthesiologists. We report 2 cases of diagnosis of DVT that resulted from ultrasound for difficult peripheral venous access. In the course of ultrasound-guided procedures, anesthesiologists are in a position to incidentally discover DVT and potentially change management to reduce the likelihood of DVT leading to pulmonary embolism.

Imaging approach to COVID-19 associated pulmonary embolism

The novel coronavirus disease-2019 (COVID-19) illness and deaths, caused by the severe acute respiratory syndrome coronavirus-2, continue to increase. Multiple reports highlight the thromboembolic complications, such as pulmonary embolism (PE), in COVID-19. Imaging plays an essential role in the diagnosis and management of COVID-19 patients with PE. There continues to be a rapid evolution of knowledge related to COVID-19 associated PE. This review summarises the current understanding of prevalence, pathophysiology, role of diagnostic imaging modalities, and management, including catheter-directed therapy for COVID-19 associated PE. It also describes infection control considerations for the radiology department while providing care for patients with COVID-19 associated PE.

Non-invasive diagnosis of deep vein thrombosis from ultrasound imaging with machine learning

Deep vein thrombosis (DVT) is a blood clot most commonly found in the leg, which can lead to fatal pulmonary embolism (PE). Compression ultrasound of the legs is the diagnostic gold standard, leading to a definitive diagnosis. However, many patients with possible symptoms are not found to have a DVT, resulting in long referral waiting times for patients and a large clinical burden for specialists. Thus, diagnosis at the point of care by non-specialists is desired. We collect images in a pre-clinical study and investigate a deep learning approach for the automatic interpretation of compression ultrasound images. Our method provides guidance for free-hand ultrasound and aids non-specialists in detecting DVT. We train a deep learning algorithm on ultrasound videos from 255 volunteers and evaluate on a sample size of 53 prospectively enrolled patients from an NHS DVT diagnostic clinic and 30 prospectively enrolled patients from a German DVT clinic. Algorithmic DVT diagnosis performance results in a sensitivity within a 95% CI range of (0.82, 0.94), specificity of (0.70, 0.82), a positive predictive value of (0.65, 0.89), and a negative predictive value of (0.99, 1.00) when compared to the clinical gold standard. To assess the potential benefits of this technology in healthcare we evaluate the entire clinical DVT decision algorithm and provide cost analysis when integrating our approach into diagnostic pathways for DVT. Our approach is estimated to generate a positive net monetary benefit at costs up to £72 to £175 per software-supported examination, assuming a willingness to pay of £20,000/QALY.

Incremental value of compression ultrasound sonography in the emergency department

The quick evaluation of venous thromboembolism is a key point of modern medicine since the delayed diagnosis is associated with a worse prognosis. Venous ultrasound (VU) is a sensitive and rapidly performed test in cases of suspected deep venous thrombosis. Various protocols have been proposed for its execution, such as the study of the whole deep venous circulation of the lower limb or the analysis of the femoral-popliteal area. The aim is to detect a vessel thrombus and the most sensitive element is the non-compressibility with the probe. Initially, the thrombus is hypoechogenic and adherent to the vessel; later, it tends to organize and recanalize. Usually, in the early stages, the risk of embolism is higher. The role of studying the iliac axis and calf veins is still uncertain. VU is not useful for assessing response to anticoagulation therapy and it is unclear whether the persistence of thrombotic abnormalities can guide on a possible prolongation of therapy.

Cost-minimization modeling of venous thromboembolism diagnostics: performing limited compression ultrasound in primary health care reduces costs compared to referring patients to a hospital

Background

The aim of this retrospective study was to determine whether diagnosing a deep venous thrombosis (DVT) in primary health care using limited compression ultrasound (LCUS) can save resources compared to referring these patients to hospital. According to the current literature, LCUS is as safe as a standard protocol based on a whole-leg ultrasound (US).

Methods

We created a standardized patient for this cost-analysis model based on 76 patients that were referred to hospital for a suspected DVT. Travel distance to the health care centre and hospital was calculated based on the home address. Hospital costs were acquired from the hospital price list and Finnish legislation. Time spent in the hospital was retrieved from hospital statistics. Time spent in the health care centre and travelling were estimated and monetized based on average salary. The cost of participating physicians attending a US training course was estimated based on the national average salary of a general practitioner as well as the course participation fee. A cost-minimization modeling was performed for this standardized patient comparing the total costs, including private and public costs, of standard and LCUS strategies.

Results

The total costs per patient of standard and LCUS pathways were 1151.52€ and 301.94€ [difference 849.59€ (95% CI 800.21€–898.97€, p < 0.001)], respectively. The real-life costs of these strategies, considering that some patients are probably referred to hospital every year and including training costs, are 1151.53€ and 508.69€ [difference 642.84€ (95% CI 541.85€–743.82€)], respectively.

Conclusion

Using LCUS in diagnosing DVT in primary health care instead of referring these patients to the hospital is shown to save a significant amount of public and private resources.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13089-021-00227-5.

Risk Factors and Anticoagulation Therapy in Patients With Isolated Distal Deep Vein Thrombosis in the Early Post-operative Period After Thoracic Surgery

Background: Isolated distal deep vein thrombosis (IDDVT) accounts for ~50% of all patients diagnosed with deep venous thrombosis (DVT), but the diagnosis and optimal management of IDDVT remains unclear and controversial. The aim of this study was to explore potential risk factors and predictors of IDDVT, and to evaluate different strategies of anticoagulation therapy.

Methods: A total of 310 consecutive patients after thoracic surgery, who underwent whole-leg ultrasonography as well as routine measurements of D-dimer levels before and after surgery were evaluated. The general clinical data, anticoagulant therapy, pre- and postoperative D-dimer levels were collected. Differences between IDDVT, DVT and non-DVT groups were calculated. Logistic regression analysis was used to analyze risk factors of postoperative IDDVT.

Results: Age and postoperative D-dimer levels were significantly higher in IDDVT group than in non DVT group (p = 0.0053 and p < 0.001, respectively). Logistic regression analysis showed that postoperative D-dimer level was a significant independent predictor of IDDVT even when adjusted for age and operation method (p = 0.0003). There were no significant side effects associated with both full-dose and half-dose anticoagulation regimens. Half-dose therapy was associated with a significant decrease in the requirement for anticoagulation medications after discharge (p = 0.0002).

Conclusion: Age and D-dimer levels after surgery are strong predictors of IDDVT following thoracic surgery. Half-dose therapeutic anticoagulation has the same efficiency in preventing IDDVT progression, is not associated with any additional risks of adverse effects compared to a full-dose regimen, and may be adopted for treating IDDVT patients after thoracic surgery.

Multimodal thromboprophylaxis in low-risk patients undergoing lower limb arthroplasty: A retrospective observational cohort analysis of 1400 patients with ultrasound screening

PURPOSE

This study reports the results of a multimodal thromboprophylaxis protocol for lower limb arthroplasty involving risk stratification, intraoperative calf compression, aspirin prophylaxis and early (within 4 h) post-operative mobilisation facilitated by the use of local infiltration analgesia. The study also aimed to identify risk factors for venous thromboembolism (VTE) within a 3-month period following surgery for patients deemed not at elevated risk.

METHODS

Patients undergoing knee/hip arthroplasty or hip resurfacing were preoperatively screened for VTE risk factors, and those at standard risk were placed on a thromboprophylaxis protocol consisting of intraoperative intermittent calf compression during surgery, 300 mg/day aspirin for 6 weeks from surgery and early mobilisation. Patients were screened bilaterally for deep vein thrombosis (DVT) on post-operative days 10-14. If proximal DVT was detected, patients were anticoagulated and outcomes were recorded. Symptomatic VTE within 3 months of surgery were recorded separately. Patient notes were retrospectively collated and cross-validated against ultrasound reports.

RESULTS

At initial screening, the rate of proximal DVT was 0.54% (1.1% for knee and 0.27% for hip), and distal DVT was 6.63% (20.11% for knee and 2.31% for hip). One small, nonfatal pulmonary embolism (PE) was detected within 3 months of surgery (0.28% of total knee arthroplasty patients or 0.07% of total). All proximal DVTs were treated successfully with anticoagulants; however, one patient suffered a minor PE approximately 10 months post-operatively. Regression analysis identified knee implant and advanced age as independent risk factors for VTE in this cohort.

CONCLUSION

Although knee arthroplasty patients remained at higher risk than hip replacement/resurfacing patients, the incidence and outcomes of VTE remained positive compared with protocols involving extended immobilisation, and episodes of PE were extremely rare. Thus, we conclude that patients at standard preoperative risk of VTE may safely be taken through the post-operative recovery process with a combination of intraoperative mechanical prophylaxis, early mobilisation and post-operative aspirin, with closer attention required for older patients and those undergoing knee surgery.

Teaching limited compression ultrasound to general practitioners reduces referrals of suspected DVT to a hospital: a retrospective cross-sectional study

BACKGROUND

The aim of this study was to retrospectively determine whether teaching limited compression ultrasound (LCUS) to general practitioners (GP) would reduce the number of patients with a suspected lower extremity DVT referred to a hospital for ultrasound (US) examination. According to the current literature, an LCUS protocol is a safe way to diagnose or exclude lower extremity deep venous thrombosis (DVT) and a good option to radiologist-performed whole-leg ultrasound (US), especially in remote health care units where there may be a limited availability of radiological services.

METHODS

Between 2015 and 2016, altogether 13 GPs working in the same primary care unit were trained in LCUS for DVT diagnostics. The number of annual referrals due to a suspected DVT from Saarikka primary care unit to the closest hospital was evaluated before and after training. The incidence of DVT was considered to be constant. Thus, the reduction of referrals was attributed to the fact that these patients were diagnosed and treated in primary health care. Incidence rate ratio of hospital referrals was calculated. As a measure of safety, all patients diagnosed with a pulmonary embolism in the nearest hospital were evaluated to determine if they had undergone LCUS by a GP in primary care.

RESULTS

Before training in 2014, there were 60 annual referrals due to a suspected DVT; in 2017, after training, the number was reduced to 16, i.e., a 73.3% decrease. The incidence of referrals decreased from 3.21 to 0.89 per 1000 person-years. (IRR 3.58, 95% CI 2.04-6.66, p < 0.001). No patient with a pulmonary embolism diagnosis had LCUS performed previously, indicating that there were no false negatives, resulting in pulmonary embolism.

CONCLUSIONS

Teaching LCUS to GPs can safely reduce the number of patients with a suspected DVT referred to a hospital substantially.

Relaxation-Enhanced Angiography without Contrast and Triggering (REACT) for pelvic MR venography in comparison to balanced gradient-echo and T2-weighted spin-echo techniques

RATIONALE AND OBJECTIVES

To evaluate the imaging capabilities of the REACT pulse sequence in pelvic venous vessels compared to conventional non-contrast pulse sequences.

MATERIALS AND METHODS

In addition to routine MRI venography, non-contrast enhanced REACT pulse sequence was performed in 4 healthy volunteers and 21 patients with suspected or known deep venous thrombosis and post thrombotic syndrome. Acquired images were independently interpreted by two MRI radiologists. The sequence performance was subjectively evaluated on a four-point scale regarding the delineation of small peripheral, midsize and large proximal venous vessels, the imaging of vascular pathologies, and the degradation due to artifacts. To evaluate statistical differences in diagnostic accuracy Friedman's test with Dunn's correction was used.

RESULTS

REACT depicted the peripheral veins superior to bTFE and T2-TSE with an average score of 3.39 compared to 2.33 in bTFE and 1.77 in T2-TSE. In midsize vessels REACT performed significantly better than T2-TSE (1.94) and bTFE (2.68) with a score of 3.64. For the large proximal vessels REACT (3.39), bTFE (3.33) and T2-TSE (3.56) performed equally without statistical difference. Visibility of venous pathologies was found to be equal between REACT (3.62), bTFE (3.51) and T2-TSE (3.52). The image degradation due to artifacts was rated best in T2-TSE (3.56), followed by REACT (3.39) and bTFE (3.33).

CONCLUSIONS

REACT is a promising tool for the visualization of the pelvic venous system using magnetic resonance imaging.

Comparison Between the Diagnostic Performance of 1.5 T and 3.0 T field Strengths for Detecting Deep Vein Thrombosis Using Magnetic Resonance Black-Blood Thrombus Imaging

BACKGROUND

Magnetic resonance (MR) black-blood thrombus imaging (BTI) is an accurate diagnostic technique for detecting deep vein thrombosis (DVT) but to date there have been no studies comparing the diagnostic performance and consistency of this technique at different field strengths. In this study, we evaluated and compared the diagnostic performance of BTI for detecting DVT at 1.5 T and 3.0 T field strengths.

METHODS

A total of 40 patients with DVT were enrolled in this study from November 2015 up to October 2018. All patients underwent BTI, a contrast-free T1-weighted MR imaging technique for detecting DVT, and contrast-enhanced MR venography (CE-MRV) at 1.5 T or 3.0 T field strengths. The MR data analyses used 1160 segments from the venous lumen of the 40 patients. The signal-to-noise ratio and contrast-to-noise ratio between thrombus and muscle/lumen were calculated to compare BTI at 1.5 T or 3.0 T to determine the image performance for thrombus detection at 1.5 T or 3.0 T. Two physicians blinded to the study evaluated all BTI images and calculated the overall sensitivity (SE), specificity (SP), positive predictive value (PPV) and negative predictive value (NPV), accuracy, and diagnostic consistency at 1.5 T and 3.0 T. These images and values were compared to control CE-MRV images that had been obtained by 2 senior physicians and used as reference standards. In addition, the reliability and consistency of diagnoses between observers were also evaluated.

RESULTS

Two study-blind physicians reviewed all BTI images to diagnose thrombus and to determine SE, SP, PPV, NPV, and accuracy. There were no statistical differences in SE, SP, PPV, NPV, or accuracy between the 1.5 T and 3.0 T groups.

CONCLUSIONS

Black-blood thrombus imaging has high SE, SP, and accuracy for DVT diagnosis both at 1.5 T and 3.0 T field strengths. This noninvasive diagnostic technique, which does not require the use of contrast agents, can be widely used in the clinical screening of DVT and follow-up after treatment.

Time-efficient and contrast-free magnetic resonance imaging approach to the diagnosis of deep vein thrombosis on black-blood gradient-echo sequence: a pilot study

Background

Black-blood thrombus imaging (BTI) has shown to be advantageous for the diagnosis of deep vein thrombosis (DVT). However, previous techniques using fast spin echo have a high specific absorption rate. As DANTE (delay alternating with nutation for tailored excitation) black-blood preparation can suppress blood flows over a broad range of velocities, we hypothesized that a DANTE black-blood preparation combined with a fast low-angle shot (FLASH) gradient-echo readout-DANTE-FLASH could be used to diagnose DVT.

Methods

Eleven healthy volunteers and 30 suspected DVT patients were recruited to undergo DANTE-FLASH and magnetic resonance direct thrombus imaging (MRDTI). The suspected DVT patients were also examined by ultrasound (US). For the segment level, a total of 1,066 venous vessel segments were analyzed. Using US and MRDTI as the references, the sensitivity (SE), specificity (SP), positive and negative predictive values (PPV and NPV), and accuracy (ACC) of DANTE-FLASH were calculated. To quantitatively compare image quality between DANTE-FLASH and MRDTI, image signal-to-noise ratio (SNR), apparent contrast-to-noise ratio (CNR) between muscle and the venous lumen, and the apparent CNR between the thrombus and venous lumen were measured. Additionally, diagnostic confidence, image quality, and clot burden were also evaluated.

Results

Using the consensus results of US and MRDTI as a standard reference, the diagnostic SE, SP, PPV, NPV, and ACC of DANTE-FLASH for the 2 readers were 97.0% and 93.2%, 99.0% and 98.2%, 93.4% and 87.9%, 99.6% and 99.0%, and 98.8% and 97.6%, respectively. According to the image quantitative analysis results, DANTE-FLASH demonstrated higher image SNR and CNR than MRDTI. The image quality and diagnostic confidence scores of DANTE-FLASH were higher than MRDTI (3.66±0.44 vs. 3.52±0.52, P<0.001, and 3.84±0.36 vs. 3.76±0.41, P<0.001). There was excellent agreement between DANTE-FLASH and MRDTI on clot burden evaluation.

Conclusions

DANTE-FLASH provided better image quality than MRDTI and accurately detected thrombi. It may, therefore, serve as a safe and convenient alternative for the diagnosis of DVT.

Current Ultrasound Technologies and Instrumentation in the Assessment and Monitoring of COVID-19 Positive Patients

Since the emergence of the COVID-19 pandemic in December of 2019, clinicians and scientists all over the world have faced overwhelming new challenges that not only threaten their own communities and countries but also the world at large. These challenges have been enormous and debilitating, as the infrastructure of many countries, including developing ones, had little or no resources to deal with the crisis. Even in developed countries, such as Italy, health systems have been so inundated by cases that health care facilities became oversaturated and could not accommodate the unexpected influx of patients to be tested. Initially, resources were focused on testing to identify those who were infected. When it became clear that the virus mainly attacks the lungs by causing parenchymal changes in the form of multifocal pneumonia of different levels of severity, imaging became paramount in the assessment of disease severity, progression, and even response to treatment. As a result, there was a need to establish protocols for imaging of the lungs in these patients. In North America, the focus was on chest X-ray and computed tomography (CT) as these are widely available and accessible at most health facilities. However, in Europe and China, this was not the case, and a cost-effective and relatively fast imaging modality was needed to scan a large number of sick patients promptly. Hence, ultrasound (US) found its way into the hands of Chinese and European physicians and has since become an important imaging modality in those locations. US is a highly versatile, portable, and inexpensive imaging modality that has application across a broad spectrum of conditions and, in this way, is ideally suited to assess the lungs of COVID-19 patients in the intensive care unit (ICU). This bedside test can be done with little to no movement of the patients from the unit that keeps them in their isolated rooms, thereby limiting further exposure to other health personnel. This article presents a basic introduction to COVID-19 and the use of the US for lung imaging. It further provides a high-level overview of the existing US technologies that are driving development in current and potential future US imaging systems for lung, with a specific emphasis on portable and 3-D systems.

Safety of a strategy combining D-dimer testing and whole-leg ultrasonography to rule out deep vein thrombosis

Guidelines for the diagnostic workup of deep vein thrombosis (DVT) recommend assessing the clinical pretest probability before proceeding to D-dimer testing and/or compression ultrasonography (CUS) if the patient has high pretest probability or positive D-dimer. Referring only patients with positive D-dimer for whole-leg CUS irrespective of pretest probability may simplify the workup of DVT. In this prospective management outcome study, we assessed the safety of such a strategy. We included consecutive outpatients referred to the Emergency Department at Østfold Hospital, Norway, with suspected DVT between February 2015 and November 2018. STA-Liatest D-Di Plus D-dimer was analyzed for all patients, and only patients with levels ≥0.5 µg/mL were referred for CUS. All patients with negative D-dimer or negative CUS were followed for 3 months to assess the venous thromboembolic rate. One thousand three hundred ninety-seven patients were included. Median age was 64 years (interquartile range, 52-73 years), and 770 patients (55%) were female. D-dimer was negative in 415 patients (29.7%) and positive in 982 patients (70.3%). DVT was diagnosed in 277 patients (19.8%). Six patients in whom DVT was ruled out at baseline were diagnosed with DVT within 3 months of follow-up for a thromboembolic rate of 0.5% (95% confidence interval, 0.2-1.2). A simple diagnostic approach with initial stand-alone D-dimer followed by a single whole-leg CUS in patients with positive D-dimer safely ruled out DVT. We consider this strategy to be a valuable alternative to the conventional workup of DVT in outpatients. This trial was registered at www.clinicaltrials.gov as #NCT02486445.

The prevalence of incidental uterine venous plexus thrombosis in women attending a gynecology clinic

BACKGROUND

The uterine venous plexus (UVP) is an unusual site for venous thrombosis (VT). Our aim was to determine the prevalence of UVP thrombosis (UVPT) and identify associated risk factors.

METHODS

We conducted a cross-sectional study on consecutive nonpregnant women attending our general gynecology clinic with a wide variety of presenting symptoms over a 16-month period. All women underwent a transvaginal ultrasound scan which involved detailed examination of the uterine venous plexus. Women diagnosed with incidental UVPT had thrombophilia screening, lower limb venous duplex imaging, and specialist hematological review. Logistic regression was used to examine associations between various risk factors and UVPT.

RESULTS

We screened 1383 women, 39 of whom had an incidental UVPT, giving a prevalence of 3.0% (95% confidence interval [CI], 2.1%-4.1%). Multivariate analysis showed positive associations between multiparity (odds ratio [OR] 5.75 [95% CI 2.10, 15.7]), recent surgery (OR 3.10 [95% CI 1.19, 8.07]), presence of leg varicose veins (OR 3.15 [95% CI 1.32, 7.49]), and a family history of venous thromboembolism (OR 8.74 [1.65, 46.4]) and negative associations between postmenopausal status (OR 0.36 [95% CI 0.13, 0.95]) and the development of UVPT. Thrombophilia was detected in 12.8% women diagnosed with UVPT.

CONCLUSIONS

The prevalence of incidental UVPT in a general gynecology population was 3.0%. Several demographic and clinical factors were found to be associated with UVPT. This could help to identify women at risk of this condition, and facilitate its early detection and development of evidence-based management strategies.

Molecular Ultrasound Imaging

In the last decade, molecular ultrasound imaging has been rapidly progressing. It has proven promising to diagnose angiogenesis, inflammation, and thrombosis, and many intravascular targets, such as VEGFR2, integrins, and selectins, have been successfully visualized in vivo. Furthermore, pre-clinical studies demonstrated that molecular ultrasound increased sensitivity and specificity in disease detection, classification, and therapy response monitoring compared to current clinically applied ultrasound technologies. Several techniques were developed to detect target-bound microbubbles comprising sensitive particle acoustic quantification (SPAQ), destruction-replenishment analysis, and dwelling time assessment. Moreover, some groups tried to assess microbubble binding by a change in their echogenicity after target binding. These techniques can be complemented by radiation force ultrasound improving target binding by pushing microbubbles to vessel walls. Two targeted microbubble formulations are already in clinical trials for tumor detection and liver lesion characterization, and further clinical scale targeted microbubbles are prepared for clinical translation. The recent enormous progress in the field of molecular ultrasound imaging is summarized in this review article by introducing the most relevant detection technologies, concepts for targeted nano- and micro-bubbles, as well as their applications to characterize various diseases. Finally, progress in clinical translation is highlighted, and roadblocks are discussed that currently slow the clinical translation.