The usefulness of delayed contrast-enhanced cardiovascular magnetic resonance imaging in differentiating cardiac tumors from thrombi in stroke patients

Magnetic resonance imaging for diagnostic workup of embolic stroke of undetermined source: A systematic review

BACKGROUND

Embolic stroke of undetermined source (ESUS) refers to ischemic stroke where the underlying cause of thromboembolism cannot be found despite the recommended diagnostic workup. Unidentified source of emboli hinders clinical decision-making and patient management with detrimental consequences on long-term prognosis. The rapid development and versatility of magnetic resonance imaging (MRI) make it an appealing addition to the diagnostic routine of patients with ESUS for the assessment of potential vascular and cardiac embolic sources.

AIMS

To review the use of MRI in the identification of cardiac and vascular embolic sources in ESUS and to assess the reclassification value of MRI examinations added to the conventional workup of ESUS.

SUMMARY OF REVIEW

We reviewed the use of cardiac and vascular MRI for the identification of a variety of embolic sources associated with ESUS, including atrial cardiomyopathy, left ventricular pathologies, and supracervical atherosclerosis in carotid and intracranial arteries and in distal thoracic aorta. The additional reclassification after MRI examinations added to the workup of patients with ESUS ranged from 6.1% to 82.3% and varied depending on the combination of imaging modalities.

CONCLUSION

MRI techniques allow us to identify additional cardiac and vascular embolic sources and may further decrease the prevalence of patients with the diagnosis of ESUS.

Magnetic Resonance Imaging in the Study of Cardiac Masses: A Case Series

Cardiac masses are currently studied using multimodality imaging. For diagnosis, different imaging techniques that can provide complementary information are used. Cardiac magnetic resonance imaging (MRI) has become a fundamental tool for this type of pathology owing to its ability to provide tissue characterization, spatial accuracy, and the anatomic relationships of the different structures. This study presents a series of four clinical cases with an initial diagnosis of a cardiac mass. All cases were evaluated at a single center, and patients were aged 57 to 72 years. An etiological study was conducted on all patients using different imaging techniques, including MRI. This study describes the diagnostic and therapeutic procedures of the four cases, which included two intracardiac metastases and two benign tumors. Cardiac MRI was decisive in the diagnostic process, determining the clinical decision-making in all four cases. Cardiac MRI has emerged as a pivotal technique in the diagnosis of cardiac masses. It can provide a highly accurate histological diagnosis without the need for invasive techniques.

Diagnostic and Therapeutic Challenges Associated With Left Ventricular Tumors

Cardiac tumors are uncommon. Sometimes it is challenging to differentiate non-invasively between different kinds of cardiac tumors and thrombi, which is critical to dictate the subsequent treatment. In addition, not all high-risk cardiac tumors are amenable to surgical resection posing a therapeutic challenge. We report a case of cardiac papillary fibroelastoma in the left ventricular cavity with a 10-year follow-up, with no embolic complications.

Radiomics Feature Analysis Using Native T1 Mapping for Discriminating Between Cardiac Tumors and Thrombi

RATIONALE AND OBJECTIVES

Accurate differential diagnosis is essential because cardiac tumors and thrombi have different prognoses and therapeutic approaches. Native T1 map provides an objective T1 time quantifications of cardiac mass without the need for a contrast agent. We examined the diagnostic performance of radiomics features for differentiating cardiac tumors from thrombi using cardiac magnetic resonance imaging T1 mapping technique compared to that of late gadolinium enhancement (LGE) imaging.

MATERIALS AND METHODS

This retrospective study included 22 cardiac tumors and 21 thrombi of 41 patients who underwent cardiac magnetic resonance imaging from December 2013 to May 2018. Fifty-six radiomics features were extracted from native T1 images. The least absolute shrinkage and selection operator method was used for feature selection and rad score extraction. The diagnostic performance of the rad score was compared to that of the native T1 value (mean T1) and LGE ratio.

RESULTS

The area under the receiver operating characteristic curve of the rad score was higher than that of the mean T1 and LGE ratio (0.98 vs. 0.86 vs. 0.82, p = 0.001). With the optimal cut-off value, the rad score showed sensitivity, specificity, and accuracy of 95.4%, 95.2%, and 95.2%, respectively. Combination of the rad score and mean T1 showed a significantly higher diagnostic performance than mean T1 (p = 0.019) or LGE ratio (p = 0.022).

CONCLUSION

The rad score derived from native T1 maps can differentiate thrombi from tumors better than the mean T1 or LGE ratio. This is valuable for determining a treatment strategy for cardiac lesions in patients who cannot tolerate contrast agents.

Cardiovascular MRI Compared to Echocardiography to Identify Cardioaortic Sources of Ischemic Stroke: A Systematic Review and Meta-Analysis

Background: To compare the diagnostic yield of echocardiography and cardiovascular MRI (CMR) to detect structural sources of embolism, in patients with ischemic stroke with a secondary analysis of non-stroke populations.

Methods and Results: We searched MEDLINE/Embase (from 01.01.2000 to 24.04.2021) for studies including CMR to assess prespecified sources of embolism. Comparison included transthoracic and/or transesophageal echocardiography. Two authors independently screened studies, extracted data and assessed bias using the QUADAS-2 tool. Estimates of diagnostic yield were reported and pooled. Twenty-seven studies with 2,525 patients were included in a study-level analysis. Most studies had moderate to high risk of bias. Persistent foramen ovale, complex aortic plaques, left ventricular and left atrial thrombus were the most common pathologies. There was no difference in the yield of left ventricular thrombus detection between both modalities for stroke populations (4 studies), but an increased yield of CMR in non-stroke populations (28.1 vs. 16.0%, P < 0.001, 10 studies). The diagnostic yield in stroke patients for detection of persistent foramen ovale was lower in CMR compared to transoesophageal echocardiography (29.3 vs. 53.7%, P < 0.001, 5 studies). For both echocardiography and CMR the clinical impact of the management consequences derived from many of the diagnostic findings remained undetermined in the identified studies.

Conclusions: Echocardiography and CMR seem to have similar diagnostic yield for most cardioaortic sources of embolism except persistent foramen ovale and left ventricular thrombus. Randomized controlled diagnostic trials are necessary to understand the impact on the management and potential clinical benefits of the assessment of structural cardioaortic stroke sources.

Registration: PROSPERO: CRD42020158787.

Left Ventricular Thrombi: Insights from Cardiac Magnetic Resonance Imaging

Objective: Cardiovascular magnetic resonance imaging (CMR) late gadolinium enhancement technique (LGE) detects thrombus rather than anatomical presence based on tissue properties and is theoretically highly accurate. The present study’s goal was to compare the diagnostic accuracy obtained with various CMR techniques and transthoracic echocardiography to diagnose left ventricular thrombus and evaluate the prevalence and perspectives of left ventricular (LV) thrombus among patients with impaired systolic left ventricular function. Methods: In a single academic referral center, a retrospective database review of all CMR assessments of the established left ventricular thrombus was carried out in 206 consecutive patients with reduced systolic function for five years. To assess thrombus risk factors, clinical and imaging parameters were analyzed. Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), echocardiography, and cine-CMR sequence accuracy have been identified. LV structural parameters were quantified to detect markers for thrombus and predictors of the additive usefulness of contrast-enhanced thrombus imaging. Comparisons against LGE-CMR were made, which was used as the standard. Results: A 7.8 percent prevalence of left ventricular thrombus was identified by LGE-CMR. Cine-CMR increased the diagnostic efficiency for echocardiographic thrombus identification in this group, with sensitivity increasing from 50 percent by echocardiography to 75 percent by cine-CMR (p = 0.008). Dark blood CMR (DB-CMR) has better sensitivity and accuracy than echocardiography (p < 0.001), comparable to cine-CMR. The transmural infarct size was an independent marker for thrombus after correction for the LVEF and LV volume while considering only CMR parameters. There were significantly higher embolic events (HR = 71.33; CI 8.31–616.06, p < 0.0001) in LV thrombus patients detected by LGE-CMR. Conclusion: CMR imaging was more sensitive to left ventricular thrombi identification compared with transthoracic echocardiography. An additional parameter available from LGE-CMR and shown as an independent risk factor for left ventricular thrombus is the myocardial scar.

Diagnostic utility and clinical implication of late gadolinium enhancement cardiac magnetic resonance for detection of catheter associated right atrial thrombus

PURPOSE

To use delayed enhancement cardiac magnetic resonance (DE-CMR) as a reference standard to evaluate the prevalence and predictors of right atrial (RA) thrombus.

METHODS

In this retrospective study, 130 cancer patients with central venous catheters undergoing CMR from August 2012-January 2018 were included. CMR (cine-CMR and DE-CMR) and echocardiography were interpreted for RA thrombus blinded to other imaging results and clinical data. RA thrombus properties including the number of discrete masses, size, total thrombus area, and perimeter were also assessed. Cine-CMR was also used to quantify cardiac structure and function as markers of RA thrombus. Student's t-test was used to assess continuous variables; chi-square or Fisher's exact test were used to assess categorical variables.

RESULTS

31/130 (24%) patients had RA thrombus on DE-CMR. Echocardiography (attained in 64% of the study population) demonstrated moderate sensitivity and specificity (75%, 90% respectively) in relation to DE-CMR; cine-CMR performance was higher (sensitivity 90%, specificity 98%). Patients with and without RA thrombus had similar right-sided structure/function and cancer diagnosis. Catheter depth approached significance in patients with RA thrombus (p = 0.05). 13% of patients with RA thrombus had concomitant pulmonary embolism within 60 days of CMR vs. 2% of patients without RA thrombus (p = 0.03). Embolic events were independent of RA thrombus size (p = 0.66).

CONCLUSION

Morphologic imaging by cine-CMR and echocardiography provide limited diagnostic utility for RA thrombus as established by DE-CMR tissue characterization. Catheter-associated RA thrombus occurs independently of right-sided structure or function and is associated with clinical embolic events and catheter depth.

Quantitative Analysis of a Whole Cardiac Mass Using Dual-Energy Computed Tomography: Comparison with Conventional Computed Tomography and Magnetic Resonance Imaging

It is critical to distinguish between cardiac tumors and thrombi because they require different treatment strategies. Although accurate differentiation of these cardiac masses can be challenging, computed tomography (CT) and magnetic resonance imaging (MRI) are promising tools to improve their diagnosis. This study aimed to assess the diagnostic value of a volume-based quantification strategy using dual-energy CT to differentiate between cardiac tumors and thrombi. We prospectively enrolled 41 patients who had a cardiac mass. All patients underwent electrocardiography gated dual-energy CT. Among them, 28 patients underwent late gadolinium enhancement cardiac MRI. For quantitative analysis, the following parameters of the entire cardiac masses were measured: CT attenuation values in Hounsfield units (HU), iodine concentration (mg/ml), and signal intensity (SI) ratio. A mixed effects model was used to evaluate the significance of differences in mean CT attenuation, mean iodine concentration, and SI ratios between the cardiac tumor and thrombus groups. Diagnostic performance of each parameter was evaluated by constructing a receiver operating characteristics curve. A total of 24 cardiac tumors and 19 cardiac thrombi were analyzed. The mean iodine concentration was significantly higher in tumors than in thrombi (tumors: 2.98 ± 0.23; thrombi: 1.79 ± 0.26, p = 0.002). The diagnostic performance of iodine concentration was better than that of post-contrast HU (area under the curve [AUC]: 0.77 vs. 0.51; p < 0.001), and worse than that of SI ratio (AUC: 0.89; p = 0.04) for differentiation of cardiac tumors and thrombi. Dual-energy CT using volume-based iodine measurements can differentiate between cardiac tumors and thrombi.

Primary tumors of the heart

PURPOSE OF REVIEW

Primary cardiac tumors are a rare disease, which may have severe clinical consequences. Malignant tumors may be misdiagnosed as mixomas, with improper treatment. The aim of this review is to report how to make a differential diagnosis using old and modern tools, the latest trends in tumor classification and treatment, and their possible impact on prognosis.

RECENT FINDINGS

Papillary fibroelastomas seem to be more frequent than previously reported, and surgery is also suggested in asymptomatic patients. A genetic background has been identified for some myxomas and angiosarcomas. Malignant tumors are now classified as soft-tissue sarcomas of other organs. Immunohistochemistry and molecular diagnosis aid in recognizing several subtypes of sarcomas, leading to the possibility of targeted chemotherapy. The reports of single-center and multicenter experiences, collecting a large number of treated patients, analyzed the impact on prognosis of different approaches. The best results for survival and event-free survival are obtained with the multimodality approach.

SUMMARY

Before referring a patient with cardiac tumor to the cardiac surgeon, a presumptive diagnosis of benignity or malignancy should be obtained. Malignant tumors should be referred to a cardiac tumor team with special expertise, in order to plan the best therapeutic approach.

2014 korean guidelines for appropriate utilization of cardiovascular magnetic resonance imaging: a joint report of the korean society of cardiology and the korean society of radiology

Cardiac magnetic resonance (CMR) imaging is now widely used in several fields of cardiovascular disease assessment due to recent technical developments. CMR can give physicians information that cannot be found with other imaging modalities. However, there is no guideline which is suitable for Korean people for the use of CMR. Therefore, we have prepared a Korean guideline for the appropriate utilization of CMR to guide Korean physicians, imaging specialists, medical associates and patients to improve the overall medical system performances. By addressing CMR usage and creating these guidelines we hope to contribute towards the promotion of public health. This guideline is a joint report of the Korean Society of Cardiology and the Korean Society of Radiology.

2014 Korean guidelines for appropriate utilization of cardiovascular magnetic resonance imaging: a joint report of the Korean Society of Cardiology and the Korean Society of Radiology

Cardiac magnetic resonance (CMR) imaging is now widely used in several fields of cardiovascular disease assessment due to recent technical developments. CMR can give physicians information that cannot be found with other imaging modalities. However, there is no guideline which is suitable for Korean people for the use of CMR. Therefore, we have prepared a Korean guideline for the appropriate utilization of CMR to guide Korean physicians, imaging specialists, medical associates and patients to improve the overall medical system performances. By addressing CMR usage and creating these guidelines we hope to contribute towards the promotion of public health. This guideline is a joint report of the Korean Society of Cardiology and the Korean Society of Radiology.

Value of CMR for the differential diagnosis of cardiac masses

OBJECTIVES

The goal of this study was to evaluate the diagnostic value of CMR features for the differential diagnosis of cardiac masses.

BACKGROUND

Differentiation of cardiac tumors and thrombi and differentiation of benign from malignant cardiac neoplasms is often challenging but important in clinical practice. Studies assessing the value of cardiac magnetic resonance (CMR) in this regard are scarce.

METHODS

We reviewed the CMR scans of patients with a definite cardiac thrombus or tumor. Mass characteristics on cine, T1-weighted turbo spin echo (T1w-TSE) and T2-weighted turbo spin echo (T2w-TSE), contrast first-pass perfusion (FPP), post-contrast inversion time (TI) scout, and late gadolinium enhancement (LGE) sequences were analyzed.

RESULTS

There were 84 thrombi, 17 benign tumors, and 25 malignant tumors in 116 patients. Morphologically, thrombi were smaller (median area 1.6 vs. 8.5 cm(2); p < 0.0001), more homogeneous (99% vs. 46%; p < 0.0001), and less mobile (13% vs. 33%; p = 0.007) than tumors. Hyperintensity compared with normal myocardium on T2w-TSE, FPP, and LGE were more common in tumors than in thrombi (85% vs. 42%, 70% vs. 4%, and 71% vs. 5%, respectively; all p < 0.0001). A pattern of hyperintensity/isointensity (compared with normal myocardium) with short TI and hypointensity with long TI was very frequent in thrombi (94%), rare in tumors (2%), and had the highest accuracy (95%) for the differentiation of both entities. Regarding the characterization of neoplastic masses, malignant tumors were larger (median area 11.9 vs. 6.3 cm(2); p = 0.006) and more frequently exhibited FPP (84% vs. 47%; p = 0.03) and LGE (92% vs. 41%; p = 0.001). The ability of CMR features to distinguish benign from malignant neoplasms was moderate, with LGE showing the highest accuracy (79%).

CONCLUSIONS

CMR features demonstrated excellent accuracy for the differentiation of cardiac thrombi from tumors and can be helpful for the distinction of benign versus malignant neoplasms.

Cardiovascular magnetic resonance imaging for assessment of cardiac thrombus

Cardiac thrombus provides a substrate for embolic events and an indication for anticoagulant therapy. Cardiac magnetic resonance (CMR) imaging enables thrombus to be detected based on intrinsic tissue characteristics related to avascular tissue composition. Delayed enhancement CMR tissue characterization has been well validated for thrombus assessment using references of both pathology and clinical thromboembolic outcomes. Comparative studies have demonstrated CMR to yield improved thrombus detection compared to echocardiography, which typically detects thrombus based on anatomic appearance. Experimental studies have demonstrated the feasibility of targeted CMR contrast agents for assessing thrombus composition and chronicity. This review examines established and emerging literature on use of CMR for assessing cardiac thrombus.