Detecting Cardiac Thrombi in Acute Ischemic Stroke on Cardiac CT Versus Transoesophageal Echocardiography

Rationale: Cardiac CT acquired during the acute stroke imaging protocol (acute cardiac CT) has recently been shown to have a superior diagnostic yield than transthoracic echocardiography, which is currently the most commonly used method to screen for structural sources of cardioembolism in patients with acute ischemic stroke. The most common finding on acute cardiac CT are cardiac thrombi located in the left atrium (LA) and specifically the left atrial appendage (LAA). The higher diagnostic yield of acute cardiac CT compared to TTE is partially explained because CT allows for better visualization of the LAA, but also because cardiac thrombi may dissolve in the first days after stroke. Whether acute cardiac CT is the optimal diagnostic modality for LA thrombi in stroke patients is unknown, since data comparing it to transoesophageal echocardiography (TEE), which is the reference standard to detect LA thrombi, are lacking. The general hypothesis of this study is that acute cardiac CT is the optimal method to detect LA thrombi in ischemic stroke patients, since TEE can miss LA thrombi that dissolve in the first days after stroke. Objectives: 1. Determine whether acute cardiac CT has a higher diagnostic probability of detecting LA thrombi compared to TEE or repeated cardiac CT in the subacute phase of ischemic stroke by assessing the rate at which LA thrombi dissolve in the first days after ischemic stroke occurrence. 2. Determine the positive predictive value of acute cardiac CT compared to TEE for the detection of LA thrombi. Study design: Prospective, single-centre, observational cohort Study population: 39 patients of 18 years or older with acute ischemic stroke and a LA thrombus detected on cardiac CT acquired during the acute stroke imaging. Main study parameters/endpoints: 1. Rate at which LA thrombi visualized on acute cardiac CT dissolve in the first days after ischemic stroke. 2. False-positive rate for detection of left atrial thrombi on acute cardiac CT