Augmentation in Lower Extremity Sonography for the Detection of Deep Venous Thrombosis

Assessment of venous Doppler ultrasound findings of acute unilateral lower limb swelling in a tertiary facility in central Ghana: a retrospective analytical study

Background

Unilateral lower limb swelling has wide differential diagnoses with varying treatment plans, requiring an early and accurate diagnosis. Doppler ultrasound offers an extensive examination of the vascular system providing a platform for diagnosis and avoidance of unnecessary invasive procedures. Thus, it becomes pertinent to ensure that all the sonographic information required for the accurate diagnosis of a swollen lower limb is documented and critically analyzed in our setting, hence this study.

Results

The records of a total of 151 patients with acute unilateral lower limb swelling were retrieved, females constituted the majority (51.7%). The overall mean age was 58.70 ± 16.71 years. Statistical significance was specified at p ≤ 0.05 for this study. The males were on the average 1.86 years younger than the female, but this difference was not statistically significant (p = 0.495). Patients older than 60 years constituted the majority 72 (47.7%) followed by the 40–60-year age category 61 (40.4%), and the left lower limb was affected more often 82 (54.3%). Multiple inguinal lymphadenopathy 82 (35.7%) and edema with thickened skin and subcutaneous layers 67 (29.1%) were the two most recurrent ultrasound features. There was no significant association between the sonographic features and the diagnoses made for acute unilateral lower limb swelling, except for the feature of edema with thickened skin and subcutaneous layers (p = 0.004) and the diagnosis of cellulitis (p = 0.047) that increased significantly with age.

Conclusion

Multiple inguinal lymphadenopathy and edema of the skin and subcutaneous layers were the most recurrent ultrasound features with cellulitis as the main diagnosis for acute unilateral lower limb swelling in our setting. Edema with thickened skin and subcutaneous layers and cellulitis both increased significantly with age. Sonographers, sonologists, and radiologists must be on the look-out for these in their practices.

A Bayesian nested patch occupancy model to estimate steelhead movement and abundance

Anthropogenic impacts on riverine systems have, in part, led to management concerns regarding the population status of species using these systems. In an effort to assess the efficacy of restoration actions, and in order to improve monitoring of species of concern, managers have turned to PIT (passive integrated transponder) tag studies with in-stream detectors to monitor movements of tagged individuals throughout river networks. However, quantifying movements in a river network using PIT tag data with incomplete coverage and imperfect detections presents a challenge. We propose a flexible Bayesian analytic framework that models the imperfectly detected movements of tagged individuals in a nested PIT tag array river network. This model structure provides probabilistic estimates of up-stream migration routes for each tagged individual based on a set of underlying nested state variables. These movement estimates can be converted into abundance estimates when an estimate of abundance is available for a location within the river network. We apply the model framework to data from steelhead (Oncorhynchus mykiss) in the Upper Columbia River basin and evaluate model performance (precision/variance of simulated population sizes) as a function of population tagging rates and PIT tag array detection probability densities within the river system using a simulation framework. This simulation framework provides both model validation (precision) and the ability to evaluate expected performance improvements (variance) due to changes in tagging rates or PIT receiver array configuration. We also investigate the impact of different network configurations on model estimates. Results from such investigations can help inform decisions regarding future monitoring and management.

Comparison of a Pocket-Sized Versus a Full-Sized Ultrasound System in the Diagnosis of Proximal Lower Limb Acute Deep Vein Thrombosis

This study assessed the performance of a pocket-sized ultrasound system for the diagnosis of proximal lower limb acute deep vein thrombosis (DVT) compared to a full-sized ultrasound system. Patients who needed urgent lower limb sonograms for acute DVT were invited for the study. In each examination, the investigator scanned the patient using the pocket-sized system and then repeated the scan using the full-sized system. The sensitivity, specificity, and accuracy of the pocket-sized system were determined in reference to the full-sized system. The venous segments that failed to be visualized using the two systems were compared. One hundred lower limbs comprising 500 venous segments were examined. There were four venous segments, including two mid and two lower femoral veins in two patients who failed to be visualized using both systems. The sensitivity, specificity, and accuracy for diagnosing proximal lower limb acute DVT were 100% (95% confidence interval [CI], 94.94%–100%), 100% (95% CI, 99.05%–100%), and 100% (95% CI, 99.19%–100%), respectively. The pocket-sized ultrasound system and the full sized-ultrasound system demonstrated a comparable performance in detecting acute DVT in the leg.

ACR Appropriateness Criteria(®) on suspected lower extremity deep vein thrombosis

Lower extremity deep vein thrombosis (DVT) is a common clinical concern, with an incidence that increases with advanced age. DVT typically begins below the knee but may extend proximally and result in pulmonary embolism. Pulmonary embolism can occur in 50% to 60% of patients with untreated DVT and can be fatal. Although clinical examination and plasma d-dimer blood evaluation can often predict the presence of DVT, imaging remains critical for the diagnostic confirmation and treatment planning of DVT. Patients with above-the-knee or proximal DVT have a high risk for pulmonary embolism and are recommended to receive anticoagulation therapy. On the other hand, patients with below-the-knee or distal DVT rarely experience pulmonary embolism, and anticoagulation therapy in these patients remains controversial. However, one sixth of patients with distal DVT may experience extension of their thrombus above the knee and therefore are recommended to undergo serial imaging assessment at 1 week to exclude proximal DVT extension if anticoagulation therapy is not initiated. Ultrasound is the preferred imaging method for evaluation of patients with newly suspected lower extremity DVT. Magnetic resonance and CT venography can be especially helpful for the evaluation of suspected DVT in the pelvis and thigh. Contrast x-ray venography, the historic gold standard for DVT assessment, is now less commonly performed and primarily reserved for patients with more complex presentations such as those with suspected recurrent acute DVT.

Emergency Physician Performed Ultrasound for DVT Evaluation

Deep vein thrombosis is a common condition that is often difficult to diagnose and may be lethal when allowed to progress. However, early implementation of treatment substantially improves the disease prognosis. Therefore, care must be taken to both acquire an accurate differential diagnosis for patients with symptoms as well as to screen at-risk asymptomatic individuals. Many diagnostic tools exist to evaluate deep vein thrombosis. Compression ultrasonography is currently the most effective diagnostic tool in the emergency department, shown to be highly accurate at minimal expense. However, limited availability of ultrasound technicians may result in delayed imaging or in a decision not to image low-risk cases. Many studies support emergency physiciansas capable of accurately diagnosing deep vein thrombosis using bedside ultrasound. Further integration of ultrasound into the training of emergency physicians for use in evaluating deep vein thrombosis will improve patient care and cost-effective treatment.

[Modern ultrasound diagnostics of deep vein thrombosis in lung embolism of unknown origin]

PURPOSE

We compared innovative ultrasound techniques such as tissue harmonic imaging (THI) and cross-beam technique with speckle reduction imaging (SRI) to conventional fundamental B scan in the diagnosis of deep vein thrombosis.

MATERIAL AND METHODS

We investigated a total number of 185 patients with clinical symptoms of acute vein thrombosis. We documented the thrombosis in the patients using multifrequency ultrasound probes (5-7 MHz, 6-9 MHz, 9-14 MHz, Logig 9, GE) and recorded ultrasound sequences in fundamental B scan, THI, and cross-beam technique with SRI (grade 2). Three blinded ultrasound investigators ranked the marking of the thrombosis in each of these image modalities and graded them with the numbers 5 = weak, 4 = moderate, 3 = satisfactory, 2 = good, and 1 = excellent. We calculated the median and a t-test for each of these image modalities.

RESULTS

We diagnosed 115 thromboses (62%) in 185 investigated patients. This group could be divided as follows: 11 patients (6%) with three-level thrombosis, 37 patients (20%) with two-level thrombosis, and 67 (36%) with one-level thrombosis. The one-level thrombosis group included five (3%) patients with muscle vein thromboses, seven (4%) cases of thrombophlebitis without involvement of the deep vein system, and three (2%) cases of thrombophlebitis with involvement of the deep vein system. The t-test for unconnected samples showed significant differences (p <0.05) in iliac veins and highly significant differences (p <0.001) in the veins of the lower extremity due to the superior capabilities for detection of thrombosis using the cross-beam technique with SRI compared to THI and the fundamental B scan.

CONCLUSION

The use of high-resolution linear ultrasound probes with the concomitant application of THI and cross-beam technique with SRI facilitates the diagnosis of deep vein thrombosis. The employment of these new ultrasound modalities is an advantage in distinguishing the veins from the surrounding tissue structures and helps in evaluating the compressibility of venous vessels.

Ultrasound Evaluation of the Lower Extremity Veins

Over the past 2 decades venous ultrasonography has become the standard primary imaging technique for the initial evaluation of patients for whom there is clinical suspicion of deep venous thrombosis (DVT) of the lower extremity veins. This article addresses the role of duplex ultrasonography and color Doppler ultrasonography in today's clinical practice for the evaluation of patients suspected of harboring a thrombus in their lower extremity veins. It reviews the clinical presentation and differential diagnoses, technique, and diagnostic criteria for acute and chronic DVT. In addition, it addresses the sonographic evaluation of venous insufficiency.

Pilot study on the comprehensive economic costs of major trauma: Consequential costs are well in excess of medical costs

BACKGROUND

Trauma care is expensive. However, reliable data on the exact lifelong costs incurred by a major trauma patient are lacking. Discussion usually focuses on direct medical costs--underestimating consequential costs resulting from absence from work and permanent disability.

METHODS

Direct medical costs and consequential costs of 63 major trauma survivors (ISS >13) at a Swiss trauma center from 1995 to 1996 were assessed 5 years posttrauma. The following cost evaluation methods were used: correction cost method (direct cost of restoring an original state), human capital method (indirect cost of lost productivity), contingent valuation method (human cost as the lost quality of life), and macroeconomic estimates.

RESULTS

Mean ISS (Injury Severity Score) was 26.8 +/- 9.5 (mean +/- SD). In all, 22 patients (35%) were disabled, causing discounted average lifelong total costs of USD 1,293,800, compared with 41 patients (65%) who recovered without any disabilities with incurred costs of USD 147,200 (average of both groups USD 547,800). Two thirds of these costs were attributable to a loss of production whereas only one third was a result of the cost of correction. Primary hospital treatment (USD 27,800 +/- 37,800) was only a minor fraction of the total cost--less than the estimated cost of police and the judiciary. Loss of quality of life led to considerable intangible human costs similar to real costs.

CONCLUSIONS

Trauma costs are commonly underestimated. Direct medical costs make up only a small part of the total costs. Consequential costs, such as lost productivity, are well in excess of the usual medical costs. Mere cost averages give a false estimate of the costs incurred by patients with/without disabilities.