Background
Carotid free-floating thrombus (CFFT) was initially described using conventional angiography. These publications cautioned of a high short-term risk of stroke recurrence without a well-defined point estimate. Recently, reports of CFFT have increased with the widespread use of computed tomographic angiography for acute stroke after the donut sign description. Current prognosis and preferred diagnostic methods remains unclear.  We aimed to compare outcomes and methods of diagnosis of CFFT over fifty years.
Methods
Following PRISMA guidelines, we searched MEDLINE, EMBASE and manually for references reporting CFFT from 1960 through June 2017. We compared diagnostic methods and evaluated 30-day outcomes by decade of publication by using logistic and cox regression.
Results
3126 manuscripts were retrieved, and 273 were reviewed in detail. A total of 141 manuscripts met entry criteria, reporting on 525 patients. Increased utilization of CT angiography (CTA, OR=4.05, 95%CI 1.06-15.38, p=0.04) and duplex ultrasound (DUS, OR=2.15, 95%CI 1.28-3.63, p=0.004) were associated with decade of publication after adjusting for risk factors, clinical presentation and type of treatment. The 30-day risk of TIA, silent brain ischemia, any stroke or death was 17.1%. Decreased short-term risk of any vascular event or death (OR=0.48, 95%CI 0.31-0.74, p=0.001) was associated with decade of publication after adjusting for risk factors, clinical presentation and treatments.
Conclusion
Diagnosis of CFFT is shifting from conventional angiography to CTA or DUS. The risk of recurrent vascular events remains high in CFFT patients, but has been significantly declining over time. Early secondary stroke prevention strategies also had impacted this infrequent disease prognosis.

DIAGNOSTIC AND PROGNOSTIC TRENDS IN STROKE PATIENTS WITH CAROTID FREE FLOATING THROMBUS: A SYSTEMATIC LITERATURE REVIEW.