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Background and purpose Management of carotid artery stenosis is primarily based on the degree of luminal narrowing. The aim of this study is to compare the results of carotid doppler ultrasound (US) and CT angiography (CTA) for grading of carotid stenosis and for plaque characterization in symptomatic patients. Methods This is a cross sectional study with a total number of 35 consecutive patients having 70 carotid arteries for comparison. Grading of carotid stenosis was based on the NASCET criteria for CTA and the carotid consensus panel criteria for US. Each investigator was blinded to the results of the other modality. Results The majority of patients were aged from 60 to 69 years with male to female ratio of 3:2. Males were more commonly affected than females. The most common presenting symptom was recent stroke. Risk factors included; diabetes mellites and hypertension. Atherosclerotic ischemic heart disease was a present association. The carotid bulb and proximal ICA were the most common location for carotid plaques. Kappa analysis with 95 % confidence intervals (CIs) was utilized to determine US – CTA agreement. Both modalities showed overall good agreement (kappa = 0.63) and the concordance was better for moderate and higher grades of stenosis than for non-significant stenosis. The disagreement did not exceed one grade difference in our study sample. There was also good agreement as regards plaque morphology, while CTA was more sensitive than US in the detection of calcifications and plaque ulceration. Conclusion Doppler ultrasound when performed by an experienced sonographer can be used as a reliable first line modality for carotid stenosis grading and to categorize patients as medical and potentially surgical cases. CTA can be used as a confirmatory method for patients with borderline stenosis, for presurgical planning and for patients with suspected stenosis of the intracerebral circulation.

This paper examines the impacts of design, operational, and end-of-life (EOL) waste pathways’ parameters on material circularity in silicon solar photovoltaic (PV) modules. Dynamic material flow analysis (DMFA) quantifies time-series material flows through systems’ life cycle stages to identify hotspots of waste generation, estimate resource needs in the future, and guide sustainable material management. We introduce a DMFA framework based on U.S. electricity demand for the period 2000-2100 to assess stocks and flows of bulk PV materials (i.e., solar glass and aluminum frames). We apply the model to a range of scenarios to understand how material demands depend on selected PV-related parameters, different material circularity strategies, and recent module design trends (e.g., bifacials, large-format-high power modules). Our results enable advanced planning for future materials needs and provide insight into potential opportunities to minimize material waste.