Impact of Implementing Cardiac CT in Evaluating Patients Suspected of Cardioembolic Stroke

Prevalence of major embolic findings and incidental findings on early cardiac CT in patients with suspected ischemic stroke

PURPOSE

The purpose of this study was to assess the type and prevalence of stroke and non-stroke-related findings diagnosed on early cardiac computed tomography (CT) in patients with suspected stroke. The secondary objective was to assess the clinical consequences on the management of patients with non-stroke-related conditions identified by early cardiac CT.

MATERIALS AND METHODS

This single-center, retrospective, observational study included 1111 consecutive patients with suspected ischemic stroke between November 2018 and March 2020 who underwent cardiac CT examination in addition to the usual brain CT protocol (i.e., non-enhanced brain CT, perfusion brain CT when needed, aortic arch and supra-aortic CT angiography, and post contrast brain CT). There were 562 women and 549 men with a median age of 74 years (range: 60-85 years). Of these, 415 (415/1111; 37.4%) patients had ischemic stroke and 692 (692/1111; 62.3%) had no stroke. Cardiac CT examinations were retrospectively reviewed for cardiac CT findings at high embolic risk and clinically significant extracardiac incidental findings.

RESULTS

Among 1111 included patients, 89 (89/1111; 8.0%) had a stroke-related condition identified on early cardiac CT. This was significantly more frequent in patients with ischemic stroke (66/415; 15.9%) by comparison with those without ischemic stroke (23/696; 3.3%) (P < 0.001), with 41 patients (41/415; 9.9%) diagnosed with left atrial thrombus. Cardiac CT revealed a clinically significant non-stroke-related finding in 173 patients (173/1111; 15.6%), including 17 pulmonary embolisms (1.5%), seven suspicious pulmonary lesions (0.6%), and three breast lesions suspected to be malignant (0.3%). Twenty out of 173 patients (20/173; 11.5%) with incidental findings on early cardiac CT had a change in their management.

CONCLUSION

This study shows that adding early cardiac CT to brain CT during the acute phase of an ischemic stroke leads to a higher rate of etiological diagnoses and highlights the major interest of looking at the bigger picture.

Cardiac CT for intra-cardiac thrombus detection in embolic stroke of undetermined source (ESUS)

INTRODUCTION

Embolic stroke of undetermined source (ESUS) is a common medical challenge regarding secondary prevention strategy. Cardiac imaging is the cornerstone of embolic stroke workup, in an effort to diagnose high risk cardio-embolic sources. Cardiac computed tomography angiography (CCTA) is an emerging imaging modality with high diagnostic performance for intra-cardiac thrombus detection. The yield of CCTA implementation in addition to standard care in ESUS workup is unknown. Thus, the aim of this study was to assess the utility of CCTA in detecting intra-cardiac thrombi in the routine ESUS workup.

PATIENTS AND METHODS

This is a retrospective observational analysis of ESUS cases managed in vascular neurology unit between 2019 and 2021. Within this ESUS registry, consecutive patients undergoing CCTA were included and carefully analyzed.

RESULTS

During the study period 1066 Ischemic stroke (IS) cases were treated and evaluated. 266/1066 (25%) met ESUS criteria and 129/266 (48%) underwent CCTA. Intra-cardiac thrombus was detected by CCTA in 22/129 (17%; 95% CI, 11.5%-23.5%) patients: left ventricular thrombus (LVT) in 13 (10.1%) patients, left atrial appendage (LAA) thrombus in 8 (6.2%) patients, and left atrial (LA) thrombus in 1 (0.8%) patient. Only 5/22 (23%) of these thrombi were suspected, but could not be confirmed, in trans-thoracic echocardiogram (TTE). Among CCTA-undergoing patients, 27/129 (21%; 95% CI, 14%-28%) were found to have an indication (including pulmonary embolism) for commencing anticoagulation (AC) treatment, rather than anti-platelets. In favor of CCTA implementation, 22/266 (8.2%; 95% CI, 4.9%-11.5%) patients within the entire ESUS cohort were diagnosed with intra-cardiac thrombus, otherwise missed.

CONCLUSION

CCTA improves the detection of intra-cardiac thrombi in addition to standard care in ESUS patients. The implementation of CCTA in routine ESUS workup can change secondary prevention strategy in a considerable proportion of patients.

Feasibility of the Big 5-Jena eCS Protocol : First Experience Implementing a New Extended CT Protocol in the Initial Diagnostics of Ischemic Stroke

PURPOSE

The most common protocols in the initial diagnostic of acute ischemic stroke do not assess cardiogenic or aortic causes of embolism. These are usually evaluated later by transthoracic (TTE) or transesophageal (TEE) echocardiography. This study aimed to evaluate the feasibility of a diagnostic tool for thoracic cardiovascular thrombi according to the first experience with a new extended cardio-stroke protocol (Big 5-Jena eCS protocol) in acute stroke patients.

METHODS

Retrospective analyses of the tomography scans database of the Jena University Hospital were performed. We included a total of 67 patients in the feasibility analyses, based on the evaluation of three outcomes.

RESULTS

Primary outcome: the Big 5-Jena eCS protocol was able to detect thoracic cardiovascular thrombi in a total of 20 patients in different locations including the arch of the aorta, the aortic valve, the left atrium, the left atrial appendage, the left ventricle, and the pulmonary arteries. Secondary outcome: implementating the protocol did not result in a significant elevation of the radiation exposure compared to traditional protocols. Tertiary outcome: the new protocol identified seven cases that were considered negative by echocardiography.

CONCLUSION

The implementation of an extended cardio-stroke protocol is feasible, no significantly time-consuming, acquiring assessable imaging, and maintaining radiation exposure acceptable. The Big 5-Jena eCS protocol was also able to detect some thrombi not reported by TTE or TEE; however, due to our data's explorative character, a conclusive comparison with cardiac ultrasound is not possible. A prospective pilot study and clinical trials should be conducted to assess the diagnostic accuracy of this protocol compared to echocardiography and determine the potential impact on diagnostic and treatment decisions.

Study on Model Iterative Reconstruction Algorithm vs. Filter Back Projection Algorithm for Diagnosis of Acute Cerebral Infarction Using CT Images

The aim was to explore the application value of computed tomography (CT) perfusion (CTP) imaging based on the iterative model reconstruction (IMR) in the diagnosis of acute cerebral infarction (ACI). 80 patients with ACI, admitted to hospital, were selected as the research objects and divided randomly into a routine treatment group (group A) and a low-dose group (group B) (each group with 40 patients). Patients in group A were scanned at 80 kV–150 mAs, and the traditional filtered back projection (FBP) algorithm was employed to reconstruct the images; besides, 80 kV–30 mAs was adopted to scan the patients in group B, and the images were reconstructed by IMR1, IMR2, IMR3, iDose4 (a kind of hybrid iterative reconstruction technology), and FBP, respectively. The application values of different algorithms were evaluated by CTP based on the collected CTP images of patients and detecting indicators. The results showed that the gray and white matter CT value, SD value, SNR, CNR, and subjective image scores of patients in group B were basically consistent with those of group A (p > 0.05) after the IMR1 reconstruction, and the CT and SD of gray and white matter in patients from group B reduced steeply (p < 0.05), while SNR and CNR increased dramatically after IMR2 and IMR3 reconstruction in contrast to group A (p < 0.05). Furthermore, the cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT) of contrast agent, and time to peak (TTP) of contrast agent in patients from group B after iDose4 and IMR reconstruction were basically the same as those of group A (p > 0.05). Therefore, IMR combined with low-dose CTP could obtain high-quality CTP images of the brain with stable perfusion indicators and low radiation dose, which could be clinically applied in the diagnosis of ACI.

CT angiography vs echocardiography for detection of cardiac thrombi in ischemic stroke: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

Cardiac thrombi are an important cause of embolic stroke. We studied the diagnostic yield and diagnostic accuracy of cardiac CT angiography (CTA) compared to echocardiography for detection of cardiac thrombi in ischemic stroke patients.

METHODS

We performed a systematic review and meta-analysis of the literature on cardiac CTA versus echocardiography for detection of cardiac thrombi in ischemic stroke patients. We included studies (N ≥ 20) in which both cardiac CTA (index test) and echocardiography (reference test) were performed and data on cardiac thrombi were reported. Results were stratified for type of echocardiography: transesophageal (TEE) vs transthoracic (TTE).

RESULTS

Out of 1530 studies, 14 were included (all single center cohort studies), with data on 1568 patients. Mean age varied between 52 and 69 years per study and 66% were men. Reported time intervals ranged from 0 to 21 days between stroke and first test, and from 0 to 199 days between tests. In ten studies that compared CTA to TEE, CTA detected cardiac thrombi in 87/1385 (6.3%) patients versus 68/1385 (4.9%) on TEE (p < 0.001). In four studies comparing CTA to TTE, CTA detected thrombi in 23/183 (12.5%) patients versus 12/183 (6.6%) on TTE (p = 0.010). Pooled sensitivity and specificity of CTA versus TEE were 86.0% (95% CI 65.6-95.2) and 97.4% (95% CI 95.0-98.7), respectively.

CONCLUSIONS

CTA may be a promising alternative to echocardiography for detection of cardiac thrombi in patients with ischemic stroke, especially now that CTA is standard care for patient selection for endovascular treatment. However, studies were too heterogeneous and of insufficient methodological quality to draw firm conclusions. Large, prospective studies on this topic are warranted.