How to set-up and perform contrast-enhanced ultrasound.

Contrast-enhanced ultrasound (CEUS) is an important part of current ultrasound imaging practice. Sonographers, radiologists and other sonologists should consider CEUS as a standard tool in the diagnostic toolbox of ultrasound and utilise it liberally to solve a wide range of imaging problems whilst reducing the need to resort to CT or MRI. Setting up a CEUS service is within easy reach of all motivated practitioners.

Deep venous reflux definitions and associated clinical and physiological significance.

Background: Deep venous reflux (DVR) is often a poorly defined clinical entity. The extent of DVR that must occur for it to be clinically and hemodynamically important is not clear and is usually confounded by the presence of superficial venous reflux. This study aims to investigate the effect of the extent of DVR on clinical and hemodynamic parameters while controlling for the presence of superficial reflux.

Prospective study of natural history of deep vein thrombosis: early predictors of poor late outcomes.

Background: A proportion of patients with deep vein thrombosis (DVT) will develop postthrombotic syndrome (PTS). Currently, the only clearly identified risk factors for developing PTS are recurrent ipsilateral DVT and extensive proximal disease. The aim of the study was to assess the natural history of DVT and identify early predictors of poor clinical outcome at 5 years.

Prevalence and predictors of depression in elderly Canadians: The Canadian Study of Health and Aging.

Depression in elderly Canadians is an important but often unrecognized public health problem. Numerous studies have examined depression in the general community, but studies of depression in the elderly have generally been small and limited. The Canadian Study of Health and Aging (CSHA) includes a large and national representation of both the cognitively intact and the cognitively impaired elderly.

A prospective study of the fate of venous leg perforators after varicose vein surgery.

Objective: To describe the fate of perforator veins after surgical treatment of varicose veins and factors that influence this.

Methods: This prospective study of 104 patients assessed perforator veins by using duplex ultrasound scanning in 145 limbs before superficial vein surgery for varicose veins. Veins were marked preoperatively with ultrasound guidance and ligated with an open procedure; those missed were later treated with sclerotherapy.

Neovascularization and recurrent varicose veins: more histologic and ultrasound evidence.

Background: The recurrence of varicose veins is a common and costly consequence of varicose vein surgery. Despite the long history and vast experience of varicose vein surgery, the exact cause of recurrence is still unknown. This study aims to investigate the cause of recurrence further by correlating findings from duplex ultrasound scans, resin casts, and histologic investigation at the recurrence of the saphenofemoral junction.

"The great debate" 1: Smoking, lung cancer, and cancer epidemiology.

During the first decades of the 20th century the lung cancer death rate increased sharply in developed countries, including Canada. An association with cigarette smoking was suspected. Between 1950 and 1960 many epidemiological studies confirmed this association.

Recurrence after varicose vein surgery: a prospective long-term clinical study with duplex ultrasound scanning and air plethysmography.

Objective: We observed long-term venous ultrasound and plethysmographic changes after varicose vein surgery, to determine factors that influence recurrence.

Methods And Materials: This observational sequential prospective study was carried out in an institutional referral center with day surgery. Subjects were 92 consecutive patients, ages 20 to 75 years, with symptomatic varicose veins in 127 limbs, who were able to complete regular assessment.

Neyman's bias re-visited.

In case-control studies using prevalent cases, an apparent association may be spurious if the risk factor affects survival. In his description of this potential bias, Neyman disregarded competing risks. We use a compartment model to illustrate Neyman's bias and show that it can explain the apparent association only if the risk factor influences mortality from the disease being studied.

The detection and management of abdominal aortic aneurysm: a cost-effectiveness analysis.

Background: Abdominal aortic aneurysm (AAA) is an important cause of death in Canada, and about 80% of the deaths are due to ruptured aneurysm.

Method: To determine the most cost-effective way of controlling AAA in terms of early detection and clinical management, a cohort analysis was undertaken beginning at age 50 years, using a multistate life-table model with parameters derived from published articles. The model was used to determine (a) the optimum size for elective surgery and (b) the optimum rate of detection of intact AAA.

Risk factors for Alzheimer's disease: a prospective analysis from the Canadian Study of Health and Aging.

A prospective analysis of risk factors for Alzheimer's disease was a major objective of the Canadian Study of Health and Aging, a nationwide, population-based study. Of 6,434 eligible subjects aged 65 years or older in 1991, 4,615 were alive in 1996 and participated in the follow-up study. All participants were cognitively normal in 1991 when they completed a risk factor questionnaire.