Practicability and Diagnostic Yield of One-Stop Stroke CT with Delayed-Phase Cardiac CT in Detecting Major Cardioembolic Sources of Acute Ischemic Stroke : A Proof of Concept Study

Cardiac Computed Tomography for Cardioembolic Stroke Evaluation in a Patient With a Mechanical Aortic Valve

We present a case of cardioembolic stroke in a patient with a history of mechanical aortic valve who was compliant with anticoagulation medication. Cardiac computed tomography was used as an alternative, noninvasive means of evaluation for the cardioembolic source of stroke and identified subvalvular mobile pannus of the mechanical aortic valve.

Cardiac thrombus detected by cardiac computed tomography angiography in patients with acute ischemic stroke: a meta-analysis

Background

Detecting cardiac thrombus in patients with acute ischemic stroke is crucial in determine stroke etiology and predict prognosis. However, the prevalence of cardiac thrombus in patients with acute ischemic stroke is unclear.

Object

This study aimed to evaluate the prevalence of cardiac thrombus detected by cardiac computed tomography angiography (CCTA) in patients with acute ischemic stroke through a meta-analysis.

Methods

Embase, Web of Science, MEDLINE, and CENTRAL were searched from January 1, 2000, to May 1, 2024. We included observational studies enrolling patients who underwent CCTA within 1 month following acute ischemic stroke, and reporting the incidence of cardiac thrombi on CCTA. Meta-analysis was performed using random effects models.

Results

Twenty-six studies involving 4,516 patients were identified. The pooled prevalence of cardiac thrombus detected on CCTA in patients with acute ischemic stroke was 0.08 (95% confidence interval [CI]: 0.06-0.11). Inter-study heterogeneity was high (I2 = 88%). Among stroke type, the prevalence of atrial fibrillation, timing of CCTA and CCTA technology, the prevalence of atrial fibrillation was the only factor associated with cardiac thrombi prevalence detected by CCTA. However, atrial fibrillation was not documented in 41.5% of the patients with cardiac thrombi.

Conclusion

CCTA is a useful non-invasive imaging approach for detecting cardiac thrombus in patients with acute ischemic stroke, which might be helpful to determine the stroke etiology.

Left Atrial Appendage Opacification on Cardiac Computed Tomography in Acute Ischemic Stroke: The Clinical Implications of Slow-Flow

BACKGROUND

Left atrial appendage (LAA) slow-flow may increase the risk of ischemic stroke. We studied LAA attenuation on cardiac computed tomography in patients with acute ischemic stroke.

METHODS AND RESULTS

We used data from a prospective cohort of patients with acute ischemic stroke undergoing cardiac computed tomography during the acute stroke imaging protocol. We compared characteristics, functional outcome (modified Rankin scale: higher scores indicating worse outcome), stroke recurrence and major adverse cardiovascular events after 2-year follow-up between patients with LAA thrombus (filling defect<100 Hounsfield Unit (HU)), slow-flow (filling defect ≥100 HU) and normal filling. Of 421 patients, 31 (7%) had LAA thrombus, 69 (16%) slow-flow, and 321 (76%) normal filling. Patients with thrombus or slow-flow more often had known atrial fibrillation compared with normal filling (45%, 39%, and 9%, P<0.001). Patients with thrombus had higher National Institutes of Health Stroke Scale-scores compared with slow-flow and normal filling (18 [interquartile range, 9-22], 6 [interquartile range, 3-17], and 5 [interquartile range, 2-11], P<0.001). Compared with normal filling, there was no difference with slow-flow in functional outcome (median modified Rankin scale, 3 versus 2; acOR 0.8 [95% CI, 0.5-1.4]), stroke recurrence (adjusted hazard ratio, 0.8 [95% CI, 0.3-1.9]) or major adverse cardiovascular events (adjusted hazard ratio, 1.2 [95% CI, 0.7-2.1]), while patients with thrombus had worse functional outcome (median modified Rankin scale, 6, acOR, 3.3 [95% CI, 1.5-7.4]). In cryptogenic stroke patients (n=156) slow-flow was associated with stroke recurrence (27% versus 6%, aHR, 4.1 [95% CI, 1.1-15.7]).

CONCLUSIONS

Patients with slow-flow had similar characteristics to patients with thrombus, but had less severe strokes. Slow-flow was not significantly associated with functional outcome or major adverse cardiovascular events, but was associated with recurrent stroke in patients with cryptogenic 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.

Long-Term Clinical Implications of High-Risk Cardiac Computed Tomography Findings in Patients With Acute Ischemic Stroke

BACKGROUND

Cardiac computed tomography (CT) acquired during the initial acute stroke imaging protocol (acute cardiac CT) is increasingly used to screen for cardioembolism, but information on the long-term clinical implications of its findings is lacking.

METHODS AND RESULTS

We performed a prospective, single-center cohort study in which consecutive patients with ischemic stroke underwent ECG-gated acute cardiac CT and were followed up for 2 years. The primary outcome was functional outcome assessed using the modified Rankin Scale. Secondary outcomes were death and occurrence of major adverse cardiovascular events (composite of recurrent ischemic stroke, myocardial infarction, and cardiovascular death). We compared patients with and without a high-risk structural source of embolism on acute cardiac CT. Of 452 included patients, 55 (12.2%) had a high-risk source of embolism, predominantly cardiac thrombi (38 patients) and signs of endocarditis (8 patients). Follow-up at 2 years was complete for 430 (95.1%) patients. Patients with a high-risk source of embolism had a worse functional outcome (median modified Rankin Scale, 6 [IQR, 2-6] versus 2 [IQR, 1-5]; adjusted common odds ratio, 2.92 [95% CI, 1.62-5.25]), increased mortality rate (52.7% versus 23.7%; adjusted hazard ratio [HR], 3.28 [95% CI, 1.94-5.52]), and major adverse cardiovascular events (38.9% versus 17.5%; adjusted HR, 3.20 [95% CI, 1.80-5.69]). A high-risk source of embolism was not associated with recurrent ischemic stroke (11.1% versus 9.6%; adjusted HR, 1.30 [95% CI, 0.49-3.44]).

CONCLUSIONS

Structural high-risk sources of embolism on acute cardiac CT in patients with ischemic stroke were associated with poor long-term functional outcome and occurrence of major adverse cardiovascular events but not with recurrent stroke.

Role of cardiac computed tomography in hyperacute stroke assessment

BACKGROUND

Incorporating cardiac CT with hyperacute stroke imaging may increase the yield for cardioembolic sources. It is not clarified whether stroke severity influences on rates of intracardiac thrombus. We aimed to investigate a National Institutes of Health Stroke Scale (NIHSS) threshold below which acute cardiac CT was unnecessary.

METHODS

Consecutive patients with suspected stroke who underwent multimodal brain imaging and concurrent non-gated cardiac CT with delayed timing were prospectively recruited from 1st December 2020 to 30th November 2021. We performed receiver operating characteristics analysis of the NIHSS and intracardiac thrombus on hyperacute cardiac CT.

RESULTS

A total of 314 patients were assessed (median age 69 years, 61% male). Final diagnoses were ischemic stroke (n=205; 132 etiology-confirmed stroke, independent of cardiac CT and 73 cryptogenic), transient ischemic attack (TIA) (n=21) and stroke-mimic syndromes (n=88). The total yield of cardiac CT was 8 intracardiac thrombus and 1 dissection. Cardiac CT identified an intracardiac thrombus in 6 (4.5%) with etiology-confirmed stroke, 2 (2.7%) with cryptogenic stroke, and none in patients with TIA or stroke-mimic. All of those with intracardiac thrombus had NIHSS ≥4 and this was the threshold below which hyperacute cardiac CT was not justified (sensitivity 100%, specificity 38%, positive predictive value 4.0%, negative predictive value 100%).

CONCLUSIONS

A cutoff NIHSS ≥4 may be useful to stratify patients for cardiac CT in the hyperacute stroke setting to optimize its diagnostic yield and reduce additional radiation exposure.

Cardiac thrombus dissolution in acute ischemic stroke: A substudy of Mind the Heart

Background

Cardiac thrombi are an important cause of ischemic stroke but are infrequently detected on cardiac imaging. We hypothesized that this might be explained by early dissolution of these cardiac thrombi after stroke occurrence.

Methods

We performed a single-center observational pilot study between November 2019 and November 2020, embedded in the larger "Mind-the-Heart" study. We included patients with AIS and a cardiac thrombus in the left atrium or ventricle (filling defect <100 Hounsfield Units) diagnosed on cardiac CT that was acquired during the initial stroke imaging protocol. We repeated cardiac CT within one week to determine if the thrombus had dissolved.

Results

Five patients (four men, median age 52 years, three with atrial fibrillation and one with anticoagulation therapy at baseline) were included. Median time from symptom onset to first cardiac CT was 383 (range 42-852) minutes and median time from first to second cardiac CT was three days (range 1-7). Two patients received intravenous thrombolysis (IVT). In total, six thrombi were seen on initial CT imaging (one in the left ventricle, four in the left atrial appendage, one in the left atrium). The left atrium thrombus and one left atrial appendage thrombus had dissolved on follow-up cardiac CT, one of which was in a patient with IVT treatment.

Conclusion

This pilot study illustrates that cardiac thrombi can dissolve within days of stroke occurrence both with and without IVT treatment.

Spectral cardiac CT in acute stroke patients

Cardiac CT obtained in acute ischemic stroke patients can facilitate timely detection of cardiac sources of embolism and guide secondary prevention strategies. Spectral CT exploiting the simultaneous acquisition of separate higher-energy and lower-energy photon spectrum datasets has the potential to improve contrast between thrombi and cardiac structures. This study aimed to investigate the diagnostic value of spectral cardiac CT compared to conventional CT for the detection of cardiac thrombi in acute stroke patients. Patients with acute ischemic stroke undergoing spectral cardiac CT were retrospectively included. Conventional CT images, virtual 55 keV monoenergetic (monoE55), z-effective (zeff), and iodine density images were evaluated for the presence of thrombi. Diagnostic certainty was rated on a 5-point Likert scale. Contrast ratios were calculated for all reconstructions. 63 patients with 20 thrombi were included. Four thrombi were missed on conventional images but detected on spectral reconstructions. MonoE55 achieved the highest scores for diagnostic certainty. Contrast ratios were highest on iodine density images, followed by monoE55, conventional and zeff (p < 0.005). Spectral cardiac CT adds diagnostic benefit for the detection of intra-cardiac thrombi in acute ischemic stroke patients compared to conventional CT.

Cardiac thrombi detected by CT in patients with acute ischemic stroke: A substudy of Mind the Heart

Background:

Cardiac thrombi are a major risk factor for ischemic stroke, but are rarely diagnosed in the acute phase. We examined characteristics and functional outcome of patients with ischemic stroke and a concomitant cardiac thrombus detected on cardiac CT performed in the acute phase.

Patients and Methods:

We used data from “Mind the Heart,” a prospective cohort study in which consecutive adult patients with acute ischemic stroke underwent prospective ECG-gated cardiac CT during their acute stroke imaging protocol. We compared characteristics, functional outcome (modified Rankin scale) and stroke recurrence rate at 90 days of patients with a cardiac thrombus on CT (defined as filling defect <100 Hounsfield Units) to those without a cardiac thrombus.

Results:

Among 452 included patients, cardiac CT detected 41 thrombi in 38 (8%) patients. Thrombi were most often located in the left atrial appendage (31/38 [82%]). Patients with a cardiac thrombus more frequently had intracranial occlusions in multiple vascular territories (5% vs 0.5%, p = 0.04) and a higher baseline NIHSS score (17 [IQR 6–22] vs 5 [IQR 2–3], p < 0.001) compared to patients without a cardiac thrombus. In 13/38 (34%) patients with a cardiac thrombus, no atrial fibrillation was detected. A cardiac thrombus was associated with worse functional outcome (adjusted common odds ratio 3.18 95%CI 1.68–6.00). Recurrence rate was not significantly different (8% vs 4%, aOR 1.50 (0.39–5.82).

Discussion and Conclusion:

Cardiac CT detected a cardiac thrombus in one in every 12 patients with acute ischemic stroke, and these patients had more severe deficits, multivessel occlusions, and a worse functional outcome.