Aditya Sharma

Duplex Ultrasound in the Diagnosis of Lower-Extremity Deep Venous Thrombosis

A 26-year-old woman presented with progressive swelling and pain of the left leg within 2 months after switching to a different oral contraceptive preparation. On examination, she had marked edema and erythema of the leg from the calf to the thigh with significant tenderness to palpation. Pedal pulses were intact. The right leg was normal. Lower-extremity venous duplex ultrasound (VDUS) with B-mode compression maneuvers and Doppler evaluation was performed, and she was found to have an acute deep venous thrombosis (DVT) of the left leg that extended from the common iliac vein into the left calf (Figure 1A–1E). Figure 1. Acute iliofemoral deep venous thrombosis (DVT) in a 26-year-old woman with left leg swelling. A , B-mode image of a dilated external iliac vein (arrow) next to the external iliac artery (arrowhead). Intraluminal echoes are present, consistent with thrombus. B , Nearly complete loss of compressibility of the external iliac vein, consistent with acute DVT. C , Spectral Doppler waveform analysis with absent venous flow in the thrombosed and occluded external iliac vein (EIV). Lt DIST indicates left distal. D , B-mode image of acute DVT involving the profunda and femoral confluence into the common femoral vein. E , Color-flow Doppler image demonstrating absent flow in the common (CFV) and femoral (FV) vein and minimal flow in the profunda femoral vein (PFV; arrow). VDUS combines 2 components to assess for DVT: B-mode or gray-scale imaging with transducer compression maneuvers and Doppler evaluation consisting of color-flow Doppler imaging and spectral Doppler waveform analysis.1 The technique of compression B-mode ultrasonography for the diagnosis of DVT was first described by technologist Steve Talbot in 1982 and has subsequently been refined to become the diagnostic standard.2 B-mode imaging is used while the lower-extremity veins are compressed along their length with the ultrasound probe …

A Review on Carotid Ultrasound Atherosclerotic Tissue Characterization and Stroke Risk Stratification in Machine Learning Framework

Cardiovascular diseases (including stroke and heart attack) are identified as the leading cause of death in today’s world. However, very little is understood about the arterial mechanics of plaque buildup, arterial fibrous cap rupture, and the role of abnormalities of the vasa vasorum. Recently, ultrasonic echogenicity characteristics and morphological characterization of carotid plaque types have been shown to have clinical utility in classification of stroke risks. Furthermore, this characterization supports aggressive and intensive medical therapy as well as procedures, including endarterectomy and stenting. This is the first state-of-the-art review to provide a comprehensive understanding of the field of ultrasonic vascular morphology tissue characterization. This paper presents fundamental and advanced ultrasonic tissue characterization and feature extraction methods for analyzing plaque. Additionally, the paper shows how the risk stratification is achieved using machine learning paradigms. More advanced methods need to be developed which can segment the carotid artery walls into multiple regions such as the bulb region and areas both proximal and distal to the bulb. Furthermore, multimodality imaging is needed for validation of such advanced methods for stroke and cardiovascular risk stratification.

The United States Registry for Fibromuscular Dysplasia: New Findings and Breaking Myths

Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory arterial disease predominantly seen in women. Most FMD cases are classified as medial fibroplasia, which has the appearance of a string of beads on angiography. Until recently, FMD was thought to be seen in women in their 20s and 30s, with more than 60%-75% of cases occurring in the renal artery and 25% of cases in the carotid artery. Hypertension was regarded as the primary symptom seen in these patients followed by a small number of patients presenting with intracranial aneurysms with subarachnoid hemorrhage. The United States Registry of FMD, a patient registry, has broken many preconceived notions as well as provided more in-depth knowledge of this uncommon disorder. In this review, we discuss the findings of this registry and its use in understanding this disorder. In addition to the registry, we review other recent studies and future directions in the diagnosis and management of this disorder.

Carotid inter-adventitial diameter is more strongly related to plaque score than lumen diameter: An automated tool for stroke analysis.

To compare the strength of correlation between automatically measured carotid lumen diameter (LD) and interadventitial diameter (IAD) with plaque score (PS).

Portal vein thrombosis: When to treat and how?

Portal vein thrombosis is an unusual thrombotic condition not frequently seen in the general population; however, it has a higher prevalence in special circumstances such as in liver cirrhosis and hepatic or pancreatic malignancy. It also can be associated with significant morbidity and mortality. In this review, we discuss the current data available to guide therapy in the setting of different associated co-morbidities, hypercoagulable states, and associated thrombosis of the remaining splanchnic circulation. We discuss indications for anticoagulation, including the choice of anticoagulants, as well as the role of conservative ‘wait and watch’ and invasive therapies, such as thrombolysis, thrombectomy, and transjugular intrahepatic portosystemic shunt.

Smoking and Adverse Outcomes in Fibromuscular Dysplasia: U.S. Registry Report.

The pathophysiology of fibromuscular dysplasia (FMD) is unknown; however, smoking has been implicated as a potential contributing factor [(1,2)][1]. Prior studies have shown a higher prevalence of smoking among those with renal FMD compared with matched hypertensive control subjects [(3)][2]. The

Automated segmental-IMT measurement in thin/thick plaque with bulb presence in carotid ultrasound from multiple scanners

BACKGROUND AND OBJECTIVES Standardization of the carotid IMT requires a reference marker in ultrasound scans. It has been shown previously that manual reference marker and manually created carotid segments are used for measuring IMT in these segments. Manual methods are tedious, time consuming, subjective, and prone to errors. Bulb edge can be considered as a reference marker for measurements of the cIMT. However, bulb edge can be difficult to locate in ultrasound scans due to: (a) low signal to noise ratio in the bulb region as compared to common carotid artery region; (b) uncertainty of bulb location in craniocaudal direction; and (c) variability in carotid bulb shape and size. This paper presents an automated system (a class of AtheroEdge™ system from AtheroPoint™, Roseville, CA, USA) for locating the bulb edge as a reference marker and further develop segmental-IMT (sIMT) which measures IMT in 10mm segments (namely: s1, s2 and s3) proximal to the bulb edge. METHODS The patented methodology uses an integrated approach which combines carotid geometry and pixel-classification paradigms. The system first finds the bulb edge and then measures the sIMT proximal to the bulb edge. The system also estimates IMT in bulb region (bIMT). The 649 image database consists of varying plaque (light, moderate to heavy), image resolutions, shapes, sizes and ethnicity. RESULTS Our results show that the IMT contributions in different carotid segments are as follows: bulb-IMT 34%, s1-IMT 29.46%, s2-IMT 11.48%, and s3-IMT 12.75%, respectively. We compare our automated results against readers tracings demonstrating the following performance: mean lumen-intima error: 0.01235 ± 0.01224mm, mean media-adventitia error: 0.020933 ± 0.01539mm and mean IMT error: 0.01063 ± 0.0031mm. Our systems Precision of Merit is: 98.23%, coefficient of correlation between automated and Readers IMT is: 0.998 (p-value < 0.0001). These numbers are improved compared to previous publications by Suris group which is automated multi-resolution conventional cIMT. CONCLUSIONS Our fully automated bulb detection system reports 92.67% precision against ideal bulb edge locations as marked by the reader in the bulb transition zone.

Ultrasound-Based Automated Carotid Lumen Diameter/Stenosis Measurement and its Validation System

Objective Degree of carotid stenosis is an important predictor to assess risk of stroke. Systolic velocity-based methods for lumen diameter and stenosis measurement are subjective. Image-based methods face a challenge because of low gradients in media and intima walls. Methods This article presents AtheroEdge™ 2.0, a two-stage process for automated carotid lumen diameter measurement that combats the above challenges. Stage one uses spectral analysis based on the hypothesis that far-wall adventitia is brightest. Stage two uses lumen pixel region identification based on the assumption that blood flow has constant density. Using global and local processing, lumen boundaries are detected. This clinical system outputs lumen diameter along with stenosis severity index (SSI). Results Our database consists of institutional review board–approved 202 patients (males/females: 155/47) left and right common carotid artery images (404 images, Toshiba scanner). Two trained neuro radiologists performed manual lumen border tracings using ImgTracer™ software. The coefficient of correlation between automated and two manual readings was 0.91 and 0.92. Dice similarity and Jaccard index were 95.82%, 95.72% and 92.10%, 91.92%, respectively. The mean diameter error between automated and two manual readings was 0.27 ± 0.26 and 0.26 ± 0.28 mm, respectively. Precision of merit was 98.05% and 99.03% with respect to two readings. SSI showed 97% accuracy. Conclusions The image-based automated carotid lumen diameter and stenosis measurement system is fast, accurate, and reliable.

Prevalence of Intracranial Aneurysm in Women With Fibromuscular Dysplasia: A Report From the US Registry for Fibromuscular Dysplasia

Importance The prevalence of intracranial aneurysm in patients with fibromuscular dysplasia (FMD) is uncertain. Objective To examine the prevalence of intracranial aneurysm in women diagnosed with FMD. Design, Setting, and Participants This cross-sectional study included 669 women with intracranial imaging registered in the US Registry for Fibromuscular Dysplasia, an observational disease-based registry of patients with FMD confirmed by vascular imaging and currently enrolling at 14 participating US academic centers. Registry enrollment began in 2008, and data were abstracted in September 2015. Patients younger than 18 years at the time of FMD diagnosis were excluded. Imaging reports of all patients with reported internal carotid, vertebral, or suspected intracranial artery aneurysms were reviewed. Only saccular or broad-based aneurysms 2 mm or larger in greatest dimension were included. Extradural aneurysms in the internal carotid artery were included; fusiform aneurysms, infundibulae, and vascular segments with uncertainty were excluded. Main Outcomes and Measures Percentage of women with FMD with intracranial imaging who had an intracranial aneurysm. Results Of 1112 female patients in the registry, 669 (60.2%) had undergone intracranial imaging at the time of enrollment (mean [SD] age at enrollment, 55.6 [10.9] years). Of the 669 patients included in the analysis, 86 (12.9%; 95% CI, 10.3%-15.9%) had at least 1 intracranial aneurysm. Of these 86 patients, 25 (53.8%) had more than 1 intracranial aneurysm. Intracranial aneurysms 5 mm or larger occurred in 32 of 74 patients (43.2%), and 24 of 128 intracranial aneurysms (18.8%) were in the posterior communicating or posterior arteries. The presence of intracranial aneurysm did not vary with location of extracranial FMD involvement. A history of smoking was significantly associated with intracranial aneurysm: 42 of 78 patients with intracranial aneurysm (53.8%) had a smoking history vs 163 of 564 patients without intracranial aneurysm (28.9%; P < .001). Conclusions and Relevance The prevalence of intracranial aneurysm in women diagnosed with FMD is significantly higher than reported in the general population. Although the clinical benefit of screening for intracranial aneurysm in patients with FMD has yet to be proven, these data lend support to the recommendation that all patients with FMD undergo intracranial imaging if not already performed.

Critical Limb Ischemia: Current Approach and Future Directions

Patients with critical limb ischemia (CLI) represent the highest risk patients with peripheral artery disease (PAD), with high rates of death, amputation, and other cardiovascular events. Previously, nonsurgical options for patients with CLI were limited. However, advances in endovascular techniques such as angiosome-based revascularization and technologies such as drug-eluting balloon and stent platforms have dramatically improved the therapeutic outlook. Additionally, advances in stem cell-based therapy and angiogenic factors show promise as adjuvant medical therapy.