Cardiac magnetic resonance imaging for noninvasive assessment of cardiovascular disease during the follow-up of patients with Kawasaki disease

MRI of cardiac involvement in COVID-19

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has led to a diverse pattern of myocardial injuries, including myocarditis, which is linked to adverse outcomes in patients. Research indicates that myocardial injury is associated with higher mortality in hospitalized severe COVID-19 patients (75.8% vs 9.7%). Cardiovascular Magnetic Resonance (CMR) has emerged as a crucial tool in diagnosing both ischaemic and non-ischaemic myocardial injuries, providing detailed insights into the impact of COVID-19 on myocardial tissue and function. This review synthesizes existing studies on the histopathological findings and CMR imaging patterns of myocardial injuries in COVID-19 patients. CMR imaging has revealed a complex pattern of cardiac damage in these patients, including myocardial inflammation, oedema, fibrosis, and ischaemic injury, due to coronary microthrombi. This review also highlights the role of LLC criteria in diagnosis of COVID-related myocarditis and the importance of CMR in detecting cardiac complications of COVID-19 in specific groups, such as children, manifesting multisystem inflammatory syndrome in children (MIS-C) and athletes, as well as myocardial injuries post-COVID-19 infection or following COVID-19 vaccination. By summarizing existing studies on CMR in COVID-19 patients and highlighting ongoing research, this review contributes to a deeper understanding of the cardiac impacts of COVID-19. It emphasizes the effectiveness of CMR in assessing a broad spectrum of myocardial injuries, thereby enhancing the management and prognosis of patients with COVID-19 related cardiac complications.

ACR Appropriateness Criteria® Congenital or Acquired Heart Disease

Pediatric heart disease is a large and diverse field with an overall prevalence estimated at 6 to 13 per 1,000 live births. This document discusses appropriateness of advanced imaging for a broad range of variants. Diseases covered include tetralogy of Fallot, transposition of great arteries, congenital or acquired pediatric coronary artery abnormality, single ventricle, aortopathy, anomalous pulmonary venous return, aortopathy and aortic coarctation, with indications for advanced imaging spanning the entire natural history of the disease in children and adults, including initial diagnosis, treatment planning, treatment monitoring, and early detection of complications. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Cardiovascular magnetic resonance (CMR) and positron emission tomography (PET) imaging in the diagnosis and follow-up of patients with acute myocarditis and chronic inflammatory cardiomyopathy : A review paper with practical recommendations on behalf of the European Society of Cardiovascular Radiology (ESCR)

Advanced cardiac imaging techniques such as cardiovascular magnetic resonance (CMR) and positron emission tomography (PET) are widely used in clinical practice in patients with acute myocarditis and chronic inflammatory cardiomyopathies (I-CMP). We aimed to provide a review article with practical recommendations from the European Society of Cardiovascular Radiology (ESCR), in order to guide physicians in the use and interpretation of CMR and PET in clinical practice both for acute myocarditis and follow-up in chronic forms of I-CMP.

Non-contrast magnetic resonance angiography for systemic artery evaluation in Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is a systemic vasculitis; systemic arteries other than the coronary arteries should therefore also be evaluated. This study investigated the feasibility of evaluating coronary aneurysms, systemic artery aneurysms (SAAs), and cerebrovascular diseases in patients with KD using non-contrast magnetic resonance angiography (NC-MRA).

METHODS

Coronary artery protocols, including coronary magnetic resonance angiography (MRA) and vessel wall imaging, were performed in 57 examinations of 28 patients. Systemic artery protocol, including SAA scans and head MRA, along with coronary artery protocol, were performed in 42 examinations of 42 patients. The image quality of the SAAs was evaluated on a 4-point scale. Examination time and sedation dosage were compared between the protocols. The presence of SAAs and cerebrovascular disease was also evaluated.

RESULTS

The image quality score of SAAs was 4 (interquartile range [IQR]: 4-4) for the aorta, 4 (IQR: 3-4) for the subclavian artery, 4 (IQR: 3-4) for the renal artery, and 3 (IQR: 3-4) for the iliac artery. No differences were found between examination time (47.0 [IQR: 43.0-61.0] min vs. 51.0 [IQR: 45.0-60.0] min, p = 0.48) and sedative dose (4.63 [IQR: 3.93-5.79] mg/kg vs. 4.21 [IQR: 3.56-5.71] mg/kg, p = 0.37) between the protocols. Systemic artery protocol detected SAAs in three patients (7.1%), and cerebrovascular disease was not detected.

CONCLUSIONS

Evaluating the coronary and systemic arteries in patients with KD using NC-MRA on a single examination was possible without compromising examination time or sedation dose. The systemic artery protocol was useful in finding SAAs.

Pediatric cardiothoracic vasculitis: multimodality imaging review

The pediatric vasculitides are a relatively uncommon and heterogeneous group of disorders characterized by vessel inflammation, often with cardiothoracic involvement. Diagnosis and monitoring are often clinically challenging because of the nonspecific symptoms and laboratory markers. Thus, imaging has assumed increasing importance for early detection of disease activity, extent and complications as well as long-term monitoring pre- and post-treatment. Herein, we review the major pediatric vasculitides with frequent chest manifestations, including Takayasu arteritis, Kawasaki disease, granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, microscopic polyangiitis, Behçet disease and potential mimics. We highlight key clinical features and management considerations, emphasizing the central role of imaging.

Coronary Artery Aneurysm in Kawasaki Disease: Coronary CT Angiography through the Lens of Pathophysiology and Differential Diagnosis

Kawasaki disease (KD) is an inflammatory autoimmune vasculitis affecting the coronary arteries of very young patients, which can result in coronary artery aneurysms (CAAs) with lifelong manifestations. Accurate identification and assessment of CAAs in the acute phase and sequentially during the chronic phase of KD is fundamental to the treatment plan for these patients. The differential diagnosis of CAA includes atherosclerosis, other vasculitic processes, connective tissue disorders, fistulas, mycotic aneurysms, and procedural sequelae. Understanding of the initial pathophysiology and evolutionary arterial changes is important to interpretation of imaging findings. There are multiple applicable imaging modalities, each with its own strengths, limitations, and role at various stages of the disease process. Coronary CT angiography is useful for evaluation of CAAs as it provides assessment of the entire coronary tree, CAA size, structure, wall, and lumen characteristics and visualization of other cardiothoracic vasculature. Knowledge of the natural history of KD, the spectrum of other conditions that can cause CAA, and the strengths and limitations of cardiovascular imaging are all important factors in imaging decisions and interpretation. Keywords: Pediatrics, Coronary Arteries, Angiography, Cardiac © RSNA, 2021.

Systemic vasculitides and the role of multitechnique imaging in the diagnosis

Vasculitis, a systemic disease characterised by inflammation of the blood vessels, remains challenging to diagnose and manage. Vessel size has been the basis for classifying systemic vasculitides. Imaging plays a vital role in diagnosing this challenging disease. This review article aims (a) to summarise up-to-date literature in this field, as well as include classification updates and (b) to review available imaging techniques, recent advances, and emphasis on imaging findings to diagnose large vessel vasculitides.

Myocardial fibrosis in patients with a history of Kawasaki disease

Objectives

Cardiac magnetic resonance (CMR) measurements of myocardial extracellular volume fraction (ECV) and late gadolinium enhancement (LGE) in patients with a history of Kawasaki disease (KD) were analyzed to determine whether fibrosis was increased compared to controls.

Methods

In this single center retrospective study, patients with KD who had a CMR with ECV measurement and LGE assessment were included. The ECV was calculated in the mid-left ventricle by measuring T1 values for blood pool and myocardium before and after gadolinium administration with a Look-Locker technique. CMR findings were compared to 20 control subjects.

Results

KD patients (n = 13) had a median age at CMR of 14.9 years (range, 7.5-36.0). Control subjects (n = 20) had a median age at CMR of 16 years (range, 11.0-36.0). Twelve KD patients had coronary aneurysms. The KD patients had a significantly lower indexed LV mass (p = 0.03) and LV mass/volume ratio (p = 0.01). ECV was not significantly different in KD patients and controls (0.26 (range, 0.20-0.30) vs. 0.25 (range, 0.18-0.28), p = 0.28). One KD patient (8%) had an increased (>0.28) ECV. LGE indicating focal fibrosis was found in 5 of 13 (38%) of KD patients. Patients with LGE tended to have a higher maximum coronary dimension z-score (p = 0.09).

Conclusions

In this study of KD patients, most of whom had aneurysms, ECV did not differ significantly from that in normal controls. Focal fibrosis based on LGE was common. Future larger studies should compare ECV in KD patients with and without aneurysms to define the risk of myocardial fibrosis after KD.

Revised recommendations of the Italian Society of Pediatrics about the general management of Kawasaki disease

Aim of these revised recommendations for the general management of Kawasaki disease is to encourage its prompter recognition and warrant the most appropriate therapy, based on ascertained scientific data, raising awareness of the complications related to misdiagnosis or delayed treatment. A set of 20 synthetic operative statements is herein provided, including the definition of Kawasaki disease, its protean presentations, clinical course and seminal treatment modalities of all disease phases. The application of these recommendations should improve prognosis of Kawasaki disease and prevent the progression to permanent vascular abnormalities, thereby diminishing morbidity and mortality.

CT Angiography or Cardiac MRI for Detection of Coronary Artery Aneurysms in Kawasaki Disease

Background: Kawasaki disease (KD) is an acute vasculitis that mainly affects the coronary arteries. This inflammation can cause coronary artery aneurysms (CAAs). Patients with KD need cardiac assessment for risk stratification for the development of myocardial ischemia, based on Z-score (luminal diameter of the coronary artery corrected for body surface area). Echocardiography is the primary imaging modality in KD but has several important limitations. Coronary computed tomographic angiography (cCTA) and Cardiac MRI (CMR) are non-invasive imaging modalities and of additional value for assessment of CAAs with a high diagnostic yield. The objective of this single center, retrospective study is to explore the diagnostic potential of coronary artery assessment of cCTA vs. CMR in children with KD. Methods and Results: Out of 965 KD patients from our database, a total of 111 cCTAs (104 patients) and 311 CMR (225 patients) have been performed since 2010. For comparison, we identified 54 KD patients who had undergone both cCTA and CMR. CMR only identified eight patients with CAAs compared to 14 patients by cCTA. CMR missed 50% of the CAAs identified by cCTA. Conclusions: Our single center study demonstrates that cCTA may be a more sensitive diagnostic tool to detect CAAs in KD patients, compared to CMR.

Cardiac magnetic resonance feature tracking of the right ventricle in convalescent Kawasaki disease in a large single center

Background

The changes in right ventricular (RV) contractility of Kawasaki disease (KD) still remain unclear.

Hypothesis

We aimed to determine whether RV systolic dysfunction can be detected by cardiac magnetic resonance (CMR) feature tracking and to find its association with coronary artery lesions (aneurysm, thrombosis and stenosis).

Methods

Peak systolic myocardial longitudinal, radial and circumferential strain and the strain rate (RVSL, RVSR, RVSC, RVSRL, RVSRR and RVSRC) in the global RV and three levels (basal, middle and apical) were measured in 66 patients with convalescent KD. A total of 20 controls were included. Comparisons were made with controls and among KD subgroups divided with coronary artery lesions.

Results

RVSC (−10.575% vs. −10.760%), RVSL (−18.150% vs. −18.712%) and RVSRC (−0.815/s vs. −0.924/s) were slightly lower in KD group without significant difference. All the strain and strain rate presented lowest in the basal level. In subgroup comparison, lower RVSL and RVSRL were observed in the giant coronary artery aneurysm (CAA) group; RVSR (15.844% vs. 16.897%), RVSRR (1.245/s vs. 1.322/s) and RVSRC (−0.715/s vs. −0.895/s) were lower in thrombosed group; RVSRL (−1.27/s vs. −1.503/s) were lower in stenosis group. All the comparison in subgroups did not reach significant difference. From the analysis of receiver operating characteristic curve, RVSRL had a better ability to identify KD with giant CAA and stenosis. For the identification of thrombosis, RVSRC had a better ability.

Conclusions

Lower strain and strain rates of RV were detected in convalescent KD. More pronounced in those with persisting coronary artery lesions.

Potential Applications of PET Scans, CT Scans, and MR Imaging in Inflammatory Diseases: Part II: Cardiopulmonary and Vascular Inflammation

Detecting inflammation is among the most important aims of medical imaging. Inflammatory process involves immune system activity and local tissue response. The role of PET with fludeoxyglucose F 18 has been expanded. Systemic vasculitides and cardiopulmonary inflammatory disorders constitute a wide range of diseases with multisystemic manifestations. PET with fludeoxyglucose F 18 is useful in their diagnosis, assessment, and follow-up. This article provides an overview of the current status and potentials of hybrid molecular imaging in evaluating cardiopulmonary and vascular inflammatory diseases focusing on the potential for PET with fludeoxyglucose F 18/MR imaging and PET/CT scans.

Insights Into Coronary Artery Lesions in Kawasaki Disease

This review summarizes recent advances in understanding the development of coronary arteritis in Kawasaki disease. Kawasaki disease is the most common cause of acquired heart disease among children characterized with coronary artery abnormalities, which can cause myocardial ischemia, infarction, and even death. The pathogenic factors of Kawasaki disease and the pathological process of coronary artery disease are not clear at present, which brings challenges to the prevention and treatment of the disease. The treatment of Kawasaki disease focuses mainly on timely administration of intravenous high doses of immunoglobulin and aspirin. However, there are still some patients who do not respond well to this standard treatment, and its management remains a challenge. As a result, coronary artery lesions still occur in patients and affect their quality of life. In this review, we discuss updated research data of Kawasaki disease coronary artery lesions.

Lifetime cardiovascular management of patients with previous Kawasaki disease

Kawasaki disease (KD) is an inflammatory disorder of young children, associated with vasculitis of the coronary arteries with subsequent aneurysm formation in up to one-third of untreated patients. Those who develop aneurysms are at life-long risk of coronary thrombosis or the development of stenotic lesions, which may lead to myocardial ischaemia, infarction or death. The incidence of KD is increasing worldwide, and in more economically developed countries, KD is now the most common cause of acquired heart disease in children. However, many clinicians in the UK are unaware of the disorder and its long-term cardiac complications, potentially leading to late diagnosis, delayed treatment and poorer outcomes. Increasing numbers of patients who suffered KD in childhood are transitioning to the care of adult services where there is significantly less awareness and experience of the condition than in paediatric services. The aim of this document is to provide guidance on the long-term management of patients who have vascular complications of KD and guidance on the emergency management of acute coronary complications. Guidance on the management of acute KD is published elsewhere.

Regadenoson Stress Perfusion Cardiac Magnetic Resonance Imaging in Children With Kawasaki Disease and Coronary Artery Disease

Coronary artery (CA) stenosis and occlusion in convalescent Kawasaki disease (KD) is progressive and may result in myocardial infarction. The use of regadenoson, a strong selective CA vasodilator with low side effect profile, for stress cardiac magnetic resonance (CMR) imaging has not been studied in children with KD. The safety, feasibility, and diagnostic utility of regadenoson stress CMR was assessed in children with KD and CA abnormalities. A retrospective review of regadenoson stress CMR in children with convalescent KD was performed. Hemodynamics changes after regadenoson administration and adverse effects were recorded. First-pass perfusion was evaluated at rest and during pharmacologic stress. The results were compared with anatomic CA imaging. Forty-one stress CMR (18 sedated examinations, 44%) were performed successfully in 32 patients. Median age was 11.2 years (range 2.2 to 18.6) and weight 41 kg (range 13 to 93.4). Heart rate increased 66 ± 25% (p <0.005) after regadenoson. Minor adverse events occurred in 6 sedated and 1 unsedated patients. Hypoperfusion during stress occurred in 16 of 41 (39%), including 5 inducible, 9 inducible and fixed, and 2 fixed lesions. Late gadolinium enhancement was present in 10 of 16 with hypoperfusion and in 1 without hypoperfusion. Stress CMR had 100% positive agreement and >90% negative and overall agreement with moderate-to-severe CA stenoses. Four patients with hypoperfusion underwent revascularization for severe CA stenoses. In conclusion, regadenoson stress CMR is hemodynamically safe and feasible in children with KD and CA disease. It has excellent agreement with CA angiography and aided decision-making to proceed with revascularization.

Coronary artery assessment in Kawasaki disease with dual-source CT angiography to uncover vascular pathology

Background

Kawasaki disease (KD) is a vasculitis with formation of coronary artery aneurysms (CAAs) that can lead to myocardial ischemia. Echocardiography is the primary imaging modality for the coronary arteries despite limited visualization. Coronary angiography (CAG) is the gold standard yet invasive with high-radiation exposure. To date however, state-of-the-art CT scanners enable high-quality low-dose coronary computed tomographic angiography (cCTA) imaging. The aim of our study in KD is to report (i) the diagnostic yield of cCTA compared to echocardiography, and (ii) the radiation dose.

Methods and results

We collected data of KD patients who underwent cCTA. cCTA findings were compared with echocardiography results. In 70 KD patients (median age 15.1 years [0.5–59.5 years]; 78% male; 38% giant CAA), the cCTA identified 61 CAAs, of which 34 (56%, with a Z score > 3, in 22 patients) were not detected by echocardiography. In addition, the left circumflex (aneurysmatic in 6 patients) was always visible upon cCTA and not detected upon echocardiography. Calcifications, plaques, and/or thrombi were visualized by cCTA in 25 coronary arteries (15 patients). Calcifications were seen as early as 2.7 years after onset of disease. In 5 patients, the cCTA findings resulted in an immediate change of treatment. The median effective dose (ED) in millisievert differed significantly (p < 0.01) between third-generation dual-source and other CT scanners (1.5 [0.3–9.4] (n = 56) vs 3.8 [1.7–20.0] (n = 14)).

Conclusions

The diagnostic yield of third-generation dual-source cCTA combined with reduced radiation exposure makes cCTA a favorable diagnostic modality to complete the diagnosis and long-term treatment indications for KD.

Key Points

• cCTA is a favorable diagnostic modality to complete the diagnosis and long-term treatment indications for Kawasaki disease.

• Kawasaki disease patients with proven coronary artery involvement on echocardiography require additional imaging.

Kawasaki disease: guidelines of the Italian Society of Pediatrics, part I - definition, epidemiology, etiopathogenesis, clinical expression and management of the acute phase

The primary purpose of these practical guidelines related to Kawasaki disease (KD) is to contribute to prompt diagnosis and appropriate treatment on the basis of different specialists’ contributions in the field. A set of 40 recommendations is provided, divided in two parts: the first describes the definition of KD, its epidemiology, etiopathogenetic hints, presentation, clinical course and general management, including treatment of the acute phase, through specific 23 recommendations.

Their application is aimed at improving the rate of treatment with intravenous immunoglobulin and the overall potential development of coronary artery abnormalities in KD. Guidelines, however, should not be considered a norm that limits treatment options of pediatricians and practitioners, as treatment modalities other than those recommended may be required as a result of peculiar medical circumstances, patient’s condition, and disease severity or complications.

Myocardial Stress Perfusion MRI: Experience in Pediatric and Young-Adult Patients Following Arterial Switch Operation Utilizing Regadenoson

Dextro-transposition of the great arteries (D-TGA) is one of the most common cyanotic heart lesions. The arterial switch operation (ASO) is the preferred surgical palliation for D-TGA. One of the primary concerns following the ASO is complications arising from the coronary artery transfer. There is a need for myocardial perfusion assessment within ASO patients. There is no report on the utility of regadenoson as a stress agent in children following ASO. Our objective was to observe the safety and feasibility of regadenoson as a pharmacologic stressor for perfusion cardiac MR in a pilot cohort of pediatric and young-adult patients who have undergone ASO. We reviewed our initial experience with regadenoson stress cardiac MR in 36 pediatric and young-adult patients 15.1 ± 4.5 years (range 0.2-22 years) with history of ASO. The weight was 61.6 ± 21.5 kg (range 3.8-93 kg). All patients underwent cardiac MR because of concern for ischemia. Subjects' heart rate and blood pressure were monitored and pharmacologic stress was induced by injection of regadenoson. We evaluated their hemodynamic response and adverse effects using changes in vital signs and onset of symptoms. A pediatric cardiologist and radiologist qualitatively assessed myocardial perfusion and viability images. All stress cardiac MR examinations were completed without adverse events. Resting heart rate was 72 ± 13 beats per minute (bpm) and rose to peak of 120 ± 17 bpm (95 ± 50% increase, p < 0.005) with regadenoson. Image quality was considered good or diagnostic in all cases. A total of 11/36 (31%) patients had a perfusion defect on the stress FPP images. 14 of the 36 patients (39%) underwent cardiac catheterization within 6 months of the CMR and the findings showed excellent agreement. Regadenoson may be a useful coronary hyperemia agent to utilize for pediatric patients following arterial switch procedure when there is concern for ischemia. The ability to administer as a single bolus with one IV makes it advantageous in pediatrics. In a limited number of cases, regadenoson stress perfusion showed excellent agreement with cardiac catheterization.

Myocardial Perfusion Reserve Index in Children With Kawasaki Disease

BACKGROUND

Coronary artery lesions in patients with Kawasaki disease (KD) can impair myocardial perfusion, yet evaluation of perfusion defects by cardiac magnetic resonance (MR) in children is often qualitative.

PURPOSE

In this study we aimed to use a quantitative method of myocardial perfusion using stress cardiac MR-derived myocardial perfusion reserve index (MPRI) in children with KD and compare MPRI with ventricular mechanical performance evaluated by cardiac MR strain analysis.

STUDY TYPE

This study was a retrospective review.

SUBJECTS

Twenty-one children with a diagnosis of KD who underwent stress perfusion cardiac MR were compared with nine controls.

FIELD STRENGTH/SEQUENCE

First-pass perfusion imaging using a T₁ -weighted gradient echo sequence was performed at rest and stress after administration of adenosine with 1.5T or 3T magnets.

ASSESSMENT

The MPRI was calculated as the ratio of maximum slope of myocardial enhancement during stress compared to rest and was evaluated with the American Heart Association 17 segment model.

STATISTICAL TESTS

Demographic and clinical characteristics among KD patients and controls were compared using Student's t-test for normally distributed continuous variables, Wilcoxon-rank sum test for nonnormally distributed variables, and χ² for categorical variables.

RESULTS

There was a significant decrease in MPRI in Segment 7 (1.53 vs. 2.23, P = 0.0058) in KD patients compared with controls. The reduction in MPRI in Segment 12 approached statistical significance (1.58 vs. 2.31, P = 0.0636). Three patients who underwent serial studies had decreased MPRI longitudinally. No differences were seen in circumferential or radial strain.

DATA CONCLUSION

MPRI shows impaired myocardial perfusion in patients with KD. MPRI can change over time, suggestive of progressive coronary artery changes, which may precede fibrosis and mechanical decline. MPRI can assess segmental and global perfusion defects in patients with KD and should be a part of routine cardiac MR evaluation in KD.

LEVEL OF EVIDENCE

3 Technical Efficacy Stage 3 J. Magn. Reson. Imaging 2017.

Diagnosis, Treatment, and Long-Term Management of Kawasaki Disease: A Scientific Statement for Health Professionals From the American Heart Association

BACKGROUND

Kawasaki disease is an acute vasculitis of childhood that leads to coronary artery aneurysms in ≈25% of untreated cases. It has been reported worldwide and is the leading cause of acquired heart disease in children in developed countries.

METHODS AND RESULTS

To revise the previous American Heart Association guidelines, a multidisciplinary writing group of experts was convened to review and appraise available evidence and practice-based opinion, as well as to provide updated recommendations for diagnosis, treatment of the acute illness, and long-term management. Although the cause remains unknown, discussion sections highlight new insights into the epidemiology, genetics, pathogenesis, pathology, natural history, and long-term outcomes. Prompt diagnosis is essential, and an updated algorithm defines supplemental information to be used to assist the diagnosis when classic clinical criteria are incomplete. Although intravenous immune globulin is the mainstay of initial treatment, the role for additional primary therapy in selected patients is discussed. Approximately 10% to 20% of patients do not respond to initial intravenous immune globulin, and recommendations for additional therapies are provided. Careful initial management of evolving coronary artery abnormalities is essential, necessitating an increased frequency of assessments and escalation of thromboprophylaxis. Risk stratification for long-term management is based primarily on maximal coronary artery luminal dimensions, normalized as Z scores, and is calibrated to both past and current involvement. Patients with aneurysms require life-long and uninterrupted cardiology follow-up.

CONCLUSIONS

These recommendations provide updated and best evidence-based guidance to healthcare providers who diagnose and manage Kawasaki disease, but clinical decision making should be individualized to specific patient circumstances.

Myocardial stress perfusion magnetic resonance: initial experience in a pediatric and young adult population using regadenoson

BACKGROUND

Dipyridamole and adenosine are traditional pharmacological stressors for myocardial perfusion. Regadenoson, a selective adenosine A2A agonist, has a lower side effect profile with lower incidence of bronchospasm and bradycardia. There is a growing need for myocardial perfusion assessment within pediatrics. There is no report on the utility of regadenoson as a stress agent in children.

OBJECTIVE

To observe the safety and feasibility of regadenoson as a pharmacologic stressor for perfusion cardiac MR in a pilot cohort of pediatric patients weighing more than 40 kg who have congenital heart disease and pediatric acquired heart disease.

MATERIALS AND METHODS

We reviewed our initial experience with regadenoson stress cardiac MR in 31 pediatric patients 15.8 ± 1.7 years (range 12-22 years) with congenital heart disease and acquired heart disease. Mean patient weight was 60 ± 15 kg (range of 40-93 kg). All patients underwent cardiac MR because of concern for ischemia. The cohort included a heterogeneous group of patients at a pediatric institution with potential risk for ischemia. Subjects' heart rate and blood pressure were monitored and pharmacologic stress was induced by injection of 400 mcg of regadenoson. We evaluated their hemodynamic response and adverse effects using changes in vital signs and onset of symptoms. A pediatric cardiologist and radiologist qualitatively assessed myocardial perfusion and viability images.

RESULTS

One child was unable to complete the stress perfusion portion of the examination, but did complete the remaining portion of the CMR. Resting heart rate was 72 ± 14 beats per minute (bpm) and rose to peak of 124 ± 17 bpm (95 ± 50% increase, P < 0.005) with regadenoson. Image quality was considered good or diagnostic in all cases. Three patients had irreversible perfusion defects. Four patients had reversible perfusion defects. Nine of the patients underwent cardiac catheterization with angiography and the findings showed excellent agreement.

CONCLUSION

Regadenoson might be a safe and feasible pharmacologic stress agent for use in cardiac MR in older pediatric patients with congenital heart disease and acquired heart disease. The ease of use as a bolus and the advantage of a prolonged hyperemia make its use appealing in pediatrics. In a limited number of cases, regadenoson stress perfusion showed excellent agreement with cardiac catheterization. Regadenoson might be a viable pharmacologic stress agent in this population.

Cardiac magnetic resonance feature tracking in Kawasaki disease convalescence

Objective:

The objective of this study was to determine whether left ventricular (LV) myocardial deformation indices can detect subclinical abnormalities in Kawasaki disease convalescence. We hypothesized that subclinical myocardial abnormalities due to inflammation represent an early manifestation of the disease that persists in convalescence.

Background:

Myocardial inflammation has been described as a global finding in the acute phase of Kawasaki disease. Despite normal systolic function by routine functional measurements, reduced longitudinal strain and strain rate have been detected by echocardiography in the acute phase.

Methods and Results:

Peak systolic LV myocardial longitudinal, radial, and circumferential strain and strain rate were examined in 29 Kawasaki disease convalescent patients (15 males; mean [standard deviation] age: 11 [6.6] years; median interval from disease onset: 5.8 [5.4] years) and 10 healthy volunteers (5 males; mean age: 14 [3.8] years) with the use of cardiac magnetic resonance (CMR) feature tracking. Routine indices of LV systolic function were normal in both groups. Comparisons were made between normal controls and (i) the entire Kawasaki disease group, (ii) Kawasaki disease subgroup divided by coronary artery involvement. Average longitudinal and circumferential strain at all levels was lower in patients compared to normal controls. In subgroup analysis, both Kawasaki disease patients with and without a history of coronary involvement had similar longitudinal and circumferential strain at all levels and lower when compared to controls. There were lower circumferential and longitudinal values in Kawasaki disease patients with persisting coronary artery lesions when compared to those with regressed ones.

Conclusion:

In this CMR study in Kawasaki disease convalescent patients with preserved routine functional indices, we detected lower circumferential and longitudinal strain values compared to normal controls, irrespective of the coronary artery status.

Kawasaki disease: etiopathogenesis and novel treatment strategies

INTRODUCTION

Kawasaki disease is an acute febrile systemic vasculitis that predominantly occurs in children below five years of age. Its etiopathogenesis is still not clear, but it is thought to be a complex interplay of genetic factors, infections and immunity. Areas covered: This review article discusses in detail Kawasaki disease, with particular emphasis on the recent updates on its pathogenesis and upcoming alternate treatment options. Though self-limiting in many cases, it can lead to severe complications like coronary artery aneurysms and thrombo-embolic occlusions, and hence requires early diagnosis and urgent attention to avoid them. Intravenous immunoglobulin (IVIG) with or without aspirin has remained the sole treatment option for these cases, but 10-15% cases develop resistance to this treatment. Expert commentary: There is a need to develop additional treatment strategies for children with Kawasaki disease. Targeting different steps of pathogenesis could provide us with alternate therapeutic options.

Kawasaki disease and cardiovascular risk: a comprehensive review of subclinical vascular changes in the longer term

Studies of subclinical vascular changes post-Kawasaki disease indicate that, in general, individuals with a history of coronary artery aneurysms have increased carotid intima-media thickness, evidence of endothelial dysfunction, and increased arterial stiffness, possibly indicative of heightened cardiovascular risk. The results are less consistent for low-risk groups.

CONCLUSION

Until data are available from larger prospective studies, it is prudent to advise families of individuals with a history of Kawasaki disease to minimise traditional modifiable cardiovascular risk factors.

Imaging of acquired coronary diseases: From children to adults

Acquired coronary diseases include aneurysms, fistulae, dissections, and stenosis. Aneurysms may occur secondarily to Kawasaki disease, a childhood vasculitis, the prognosis of which depends on the coronary involvement, or they may be degenerative, infectious, inflammatory, or traumatic in origin. Fistulae develop between the coronary arterial system and a pulmonary or bronchial artery, or cardiac cavity. Dissections may occur spontaneously or may be post-traumatic. These coronary abnormalities may be found incidentally or may present as complications, infarction or rupture. The goals of this article are to understand acquired childhood and adult coronary diseases and their usual means of presentation, the ways of investigating them, and the principles of their treatment.

Cardiovascular imaging in children and adults following Kawasaki disease

Kawasaki disease (KD) is a paediatric vasculitis with coronary artery aneurysms (CAA) as its main complication. Two guidelines exist regarding the follow-up of patients after KD, by the American Heart Association and the Japanese Circulation Society. After the acute phase, CAA-negative patients are checked for cardiovascular risk assessment or with ECG and echocardiography until 5 years after the disease. In CAA-positive patients, monitoring includes myocardial perfusion imaging, conventional angiography and CT-angiography. However, the invasive nature and high radiation exposure do not reflect technical advances in cardiovascular imaging. Newer techniques, such as cardiac MRI, are mentioned but not directly implemented in the follow-up. Cardiac MRI can be performed to identify CAA, but also evaluate functional abnormalities, ischemia and previous myocardial infarction including adenosine stress-testing. Low-dose CT angiography can be implemented at a young age when MRI without anaesthesia is not feasible. CT calcium scoring with a very low radiation dose can be useful in risk stratification years after the disease. By incorporating newer imaging techniques, detection of CAA will be improved while reducing radiation burden and potential complications of invasive imaging modalities. Based on the current knowledge, a possible pathway to follow-up patients after KD is introduced. Key Points • Kawasaki disease is a paediatric vasculitis with coronary aneurysms as major complication. • Current guidelines include invasive, high-radiation modalities not reflecting new technical advances. • Cardiac MRI can provide information on coronary anatomy as well as cardiac function. • (Low-dose) CT-angiography and CT calcium score can also provide important information. • Current guidelines for follow-up of patients with KD need to be revised.

Assessment of coronary ischaemia by myocardial perfusion dipyridamole stress technetium-99 m tetrofosmin, single-photon emission computed tomography, and coronary angiography in children with Kawasaki disease: pre- and post-coronary bypass grafting

BACKGROUND

Coronary artery lesions in Kawasaki disease invasively assessed by coronary angiography. Evaluation of myocardial perfusion by single-photon emission computed tomography may identify the haemodynamic significance of coronary lesions.

OBJECTIVE

To evaluate diagnostic accuracy of dipyridamole stress technetium-99 m tetrofosmin, single-photon emission computed tomography as a possible alternative to invasive coronary angiography for detection and follow-up of myocardial ischaemia in patients with Kawasaki disease, and pre- and post-coronary bypass grafting.

PATIENTS AND METHODS

Coronary angiography and single-photon emission computed tomography were performed on 21 patients who were classified into three groups - group I (stenosis), group II (giant aneurysms), and group III (small aneurysms). Of the 21 patients, 16 (groups I and II) patients with myocardial perfusion defects, who underwent coronary bypass grafting, were followed up with single-photon emission computed tomography.

RESULT

In group I, all patients had significant coronary stenosis and 100% of them had perfusion defects in the anterior and septal walls. In group II, all patients had giant aneurysms and 83% of them had inferior and inferolateral perfusion defects. In group III, all patients had small aneurysms and 100% of them had normal perfusion. Pre-coronary bypass grafting myocardial ischaemic defects disappeared in all patients after surgery. Sensitivity, specificity, and accuracy of single-photon emission computed tomography were 94, 100, and 95%, respectively.

CONCLUSION

Technetium-99 m tetrofosmin single-photon emission computed tomography can be applied as an accurate non-invasive diagnostic technique for detecting myocardial perfusion defects with coronary artery lesions, and to show improved or even normalised perfusion of the myocardium in patients after surgical revascularisation.

Coronary artery imaging in children

Coronary artery problems in children usually have a significant impact on both short-term and long-term outcomes. Early and accurate diagnosis, therefore, is crucial but technically challenging due to the small size of the coronary artery, high heart rates, and limited cooperation of children. Coronary artery visibility on CT and MRI in children is considerably improved with recent technical advancements. Consequently, CT and MRI are increasingly used for evaluating various congenital and acquired coronary artery abnormalities in children, such as coronary artery anomalies, aberrant coronary artery anatomy specific to congenital heart disease, Kawasaki disease, Williams syndrome, and cardiac allograft vasculopathy.

Trends in pediatric cardiovascular magnetic resonance imaging

Cardiac magnetic resonance (CMR) imaging has significantly evolved over the last decade, becoming an integral part of the contemporary assessment of both congenital and acquired pediatric heart disease. Recent trends show that there is a growing interest in clinical applications and research in this field. An attempt to discuss the evolving technologies, techniques, and applications of CMR in pediatrics is not complete without understanding the current strengths of the modality. CMR complements readily available echocardiography, in many cases information from CMR can remove the need for invasive angiographic catheterization, and in other cases can be used to augment cardiac catheterisation.

Current trends in cardiac CT in children

Cardiac CT is increasingly utilized in children thanks to advanced scan techniques reducing cardiac and respiratory motion artifacts. Consequently, clinical indications of cardiac CT are not confined to the extracardiac evaluation and extended further to the assessment of intracardiac structures, coronary arteries, ventricular volumetry, and ventricular function. In addition, dual-energy CT allows the assessment of regional lung perfusion and ventilation. Four-dimensional airway evaluation is also useful and may be added to cardiac CT protocols. At the same time, a favorable risk-benefit ratio of cardiac CT can be achieved by means of various dose-saving techniques. Therefore, flexible scan techniques with minimal motion artifacts, low dose techniques without compromising excellent image quality, and extended clinical applications towards truly cardiac assessments constitute current trends in cardiac CT in children.

The emerging role of cardiovascular magnetic resonance in the evaluation of Kawasaki disease

Kawasaki disease (KD) is a vasculitis affecting the coronary and systemic arteries. Myocardial inflammation is also a common finding in KD post-mortem evaluation during the acute phase of the disease. Coronary artery aneurysms (CAAs) develop in 15-25% of untreated children. Although 50-70% of CAAs resolve spontaneously 1-2 years after the onset of KD, the remaining unresolved CAAs can develop stenotic lesions at either their proximal or distal end and can develop thrombus formation leading to ischemia and/or infarction. Cardiovascular magnetic resonance (CMR) has the ability to perform non-invasive and radiation-free evaluation of the coronary artery lumen. Recently tissue characterization of the coronary vessel wall was provided by CMR. It can also image myocardial inflammation, ischemia and fibrosis. Therefore CMR offers important clinical information during the acute and chronic phase of KD. In the acute phase, it can identify myocardial inflammation, microvascular disease, myocardial infarction, deterioration of left ventricular function, changes of the coronary artery lumen and changes of the coronary artery vessel wall. During the chronic phase, CMR imaging might be of value for risk stratification and to guide treatment.

Imaging in vasculitis

Vasculitides may involve small, medium-sized or large arteries. In small-vessel vasculitides imaging studies of lungs, nasal sinuses, cerebrum, heart and other organs are important for determining disease extension and disease activity. Aneurysms are a hallmark of medium-sized artery vasculitides. In large-vessel vasculitis, imaging studies depict homogeneous, circumferential wall swelling and smoothly tapered luminal narrowing. Ultrasound and high-resolution magnetic resonance imaging (MRI) show characteristic wall abnormalities in temporal and occipital arteries whereas ultrasound, MRI, MR angiography, computed tomography (CT), CT angiography and positron emission tomography delineate characteristic features in extra-cranial arteries that are affected in large-vessel giant cell arteritis, Takayasu arteritis and idiopathic aortitis. Conventional angiography has still its place for therapeutic interventions. Imaging has led to a better understanding of the nature and distribution of vasculitides. It significantly facilitates diagnosis of patients with suspected vasculitis.

Acquired coronary disease in children: the role of multimodality imaging

Coronary sequelae of Kawasaki disease, post-surgical coronary lesions and cardiac allograft vasculopathy are the main causes of acquired coronary pathology in childhood. Surveillance and timely recognition of coronary problems in children who are at risk of ischemic events are imperative and noninvasive imaging is increasingly utilized for these purposes. Herein, we summarize the causes of acquired coronary disease in children and discuss the role of various imaging techniques that are available to establish the diagnosis and guide management.

Coronary artery abnormalities in Kawasaki disease: comparison between CT and MR coronary angiography

BACKGROUND

Although CT coronary angiography (CTCA) and MR coronary angiography (MRCA) are increasingly used in patients with Kawasaki disease, comparison of coronary artery assessibility and diagnostic performance between the two imaging modalities has been rarely performed.

PURPOSE

To investigate which imaging modality, CTCA or MRCA, is better for evaluating coronary artery abnormalities in patients with Kawasaki disease.

MATERIAL AND METHODS

Between 2003 and 2011, 56 patients (38 boys/men; age range, 1-24 years) with Kawasaki disease underwent CTCA or MRCA (group A). Of these, 17 underwent both CTCA and MRCA (group B). Visibility of 11 coronary arterial segments in each patient was graded on a four-point scale. Coronary artery aneurysm, stenosis, and occlusion were evaluated by CTCA and MRCA, based on a reference standard obtained from cardiac catheterization, echocardiography, follow-up CTCA and MRCA, and clinical history. Coronary artery assessibility and diagnostic performance were compared between CTCA and MRCA.

RESULTS

In per-segment analysis, more segments were assessable on CTCA than on MRCA in both groups. In per-patient analysis of group B, no significant difference in the assessibility was found between CTCA (95.0%, 128.3/135 segments) and MRCA (92.4%, 124.8/135 segments) (P > 0.05). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CTCA vs. MRCA were 93.1% vs. 77.9% (P < 0.001), 99.2% vs. 99.7% (P = 0.65), 96.8% vs. 98.7% (P = 0.65), 98.2% vs. 94.1% (P < 0.001), and 98.0% vs. 94.9% (P = 0.008), respectively, in group A, and 91.8% vs. 70.4% (P < 0.001), 99.5% vs. 99.5% (P = 1.000), 98.5% vs. 98.0% (P = 1.000), 97.2% vs. 91.1% (P = 0.006), and 97.6% vs. 92.3% (P = 0.004), respectively, in group B.

CONCLUSION

Although CTCA and MRCA show comparable assessibility in per-patient analysis, CTCA shows higher diagnostic performance than MRCA for evaluating coronary artery abnormalities in patients with Kawasaki disease.

Long-term management of Kawasaki disease: implications for the adult patient

Coronary artery complications from Kawasaki disease (KD) range from no involvement to giant coronary artery aneurysms (CAA). Current long-term management protocols are calibrated to the degree of maximal and current coronary artery involvement reflecting the known likelihood of severe long-term cardiac complications. It has recently been suggested that all KD patients may be at potential risk of severe long-term cardiac complications. If this assertion was to be confirmed, current follow-up protocols would need to be extensively modified, with important implications both for the growing adult population with a previous history of KD and for the healthcare system. Based on the available evidence, patients with multiple large and/or giant CAA are at substantial risk of severe long-term cardiac complications and should have regular specialized follow-up. Patients with transient or no CAA have not been reported to be at risk of severe long-term cardiac complications. The influence of KD on the atherosclerotic process remains suboptimally defined, and should be the focus of future studies. Heightened cardiovascular risk factor surveillance and management is recommended regardless of coronary artery involvement. Based on the currently available evidence, existing long-term management protocols seem to be appropriately calibrated to the level of risk. Revised long-term management protocols should incorporate newer, noninvasive imaging methods and intensive management of atherosclerotic risk. There is insufficient evidence at this time to mandate long-term specialized follow-up and invasive testing for patients who have not had CAA.

Delayed contrast-enhanced MRI of the coronary artery wall in takayasu arteritis

BACKGROUND

Takayasu arteritis (TA) is a rare form of chronic inflammatory granulomatous arteritis of the aorta and its major branches. Late gadolinium enhancement (LGE) with magnetic resonance imaging (MRI) has demonstrated its value for the detection of vessel wall alterations in TA. The aim of this study was to assess LGE of the coronary artery wall in patients with TA compared to patients with stable CAD.

METHODS

We enrolled 9 patients (8 female, average age 46±13 years) with proven TA. In the CAD group 9 patients participated (8 male, average age 65±10 years). Studies were performed on a commercial 3T whole-body MR imaging system (Achieva; Philips, Best, The Netherlands) using a 3D inversion prepared navigator gated spoiled gradient-echo sequence, which was repeated 34-45 minutes after low-dose gadolinium administration.

RESULTS

No coronary vessel wall enhancement was observed prior to contrast in either group. Post contrast, coronary LGE on IR scans was detected in 28 of 50 segments (56%) seen on T2-Prep scans in TA and in 25 of 57 segments (44%) in CAD patients. LGE quantitative assessment of coronary artery vessel wall CNR post contrast revealed no significant differences between the two groups (CNR in TA: 6.0±2.4 and 7.3±2.5 in CAD; p = 0.474).

CONCLUSION

Our findings suggest that LGE of the coronary artery wall seems to be common in patients with TA and similarly pronounced as in CAD patients. The observed coronary LGE seems to be rather unspecific, and differentiation between coronary vessel wall fibrosis and inflammation still remains unclear.

CMR in inflammatory vasculitis

Vasculitis, the inflammation of blood vessels, can produce devastating complications such as blindness, renal failure, aortic rupture and heart failure through a variety of end-organ effects. Noninvasive imaging with cardiovascular magnetic resonance (CMR) has contributed to improved and earlier diagnosis. CMR may also be used in serial evaluation of such patients as a marker of treatment response and as an indicator of subsequent complications. Unique strengths of CMR favoring its use in such conditions are its abilities to noninvasively visualize both lumen and vessel wall with high resolution. This case-based review focuses on the large- and medium-vessel vasculitides where MR angiography has the greatest utility. Because of increasing recognition of cardiac involvement in small-vessel vasculitides, this review also presents evidence supporting greater consideration of CMR to detect and quantify myocardial microvascular disease. CMR's complementary role amidst traditional clinical, serological and other diagnostic techniques in personalized care for patients with vasculitis is emphasized. Specifically, the CMR laboratory can address questions related to extent and severity of vascular involvement. As ongoing basic and translational studies better elucidate poorly-defined underlying molecular mechanisms, this review concludes with a discussion of potential directions for the development of more targeted imaging approaches.

Evaluation of cardiac function by magnetic resonance imaging during the follow-up of patients with Kawasaki disease

BACKGROUND

Although histopathologic studies suggest persistent myocardial abnormalities after Kawasaki disease (KD), the long-term effects on cardiac function remain to be revealed. We investigated biventricular volumes, function, and the presence of myocardial fibrosis by cardiac magnetic resonance imaging during long-term follow-up of KD.

METHODS AND RESULTS

Sixty patients with a history of KD (mean age, 16.9 years; 67% men; median interval after KD onset, 11.6 years) and 20 healthy control subjects (mean age, 17.9 years; 55% men) 12 to 24 years of age underwent cardiac magnetic resonance imaging. Biventricular end-diastolic volume, end-systolic volume, stroke volume, and ejection fraction were determined. Volumetric measurements were indexed for body surface area. Late contrast enhancement was used to detect areas of myocardial fibrosis. Biventricular volumes and function did not differ significantly between patients and control subjects. There were also no significant differences between patients with and without a history of left ventricular dysfunction resulting from KD-associated myocarditis or between patients with and without coronary artery aneurysms. Only those with prior ischemic heart disease had a significantly lower left ventricular ejection fraction compared with unaffected KD cases (left ventricular ejection fraction, 51% versus 57%; P=0.012). Late contrast enhancement was observed in only 2 patients with severe coronary artery aneurysms and was typical for myocardial infarction.

CONCLUSIONS

In this cardiac magnetic resonance imaging study evaluating the cardiac function of patients with KD at long-term follow-up, we did not observe a difference in cardiac function between KD patients and control subjects, except for a subgroup of patients with ischemic heart disease as a result of severe coronary artery pathology.

New imaging modalities to assess cardiac function: not just pretty pictures

PURPOSE OF REVIEW

The following review will focus on the current advances in both echocardiography and cardiovascular MRI (CMRI) in the assessment of cardiac function.

RECENT FINDINGS

The assessment of cardiac function in pediatric patients and in congenital heart disease (CHD) patients has dramatically improved over the last several years. The advancement of transthoracic echocardiography with tissue Doppler imaging, speckle tracking, and three-dimensional echocardiography has enabled strain assessment and the ability to estimate ventricular volumes in these complex patients. In the last few decades, CMRI has become an imaging modality that is now part of the standard tools used for cardiac assessment. With superb two-dimensional and three-dimensional resolution, CMRI allows clear delineation of cardiac and extracardiac structures as well as accurate and reproducible assessment of ventricular volume and function. The most recent and robust contributions of CMRI are its ability to provide characterization of the myocardium and the development of new measurements of global and regional myocardial mechanics and function.

SUMMARY

Recent advances in echocardiography and CMRI allow a better understanding of myocardial mechanics and composition as well as accurate assessment of ventricular volume and global and regional function in the complex and unique anatomy often found in CHD patients.

Circulation: Cardiovascular Imaging Editors’ Picks

The following articles are being highlighted as part of Circulation: Cardiovascular Imaging ’s Topic Review. This series summarize the most important articles, as selected by the editors, that have been published in the Circulation portfolio. The studies included in this article represent the most significant research in clinical translation of novel imaging technologies.