Role of serial cardiac 18F-FDG PET-MRI in Anderson-Fabry disease: a pilot study

State-of-the-Art Imaging of Infiltrative Cardiomyopathies: A Scientific Statement From the American Heart Association

Infiltrative cardiomyopathies comprise a broad spectrum of inherited or acquired conditions caused by deposition of abnormal substances within the myocardium. Increased wall thickness, inflammation, microvascular dysfunction, and fibrosis are the common pathological processes that lead to abnormal myocardial filling, chamber dilation, and disruption of conduction system. Advanced disease presents as heart failure and cardiac arrhythmias conferring poor prognosis. Infiltrative cardiomyopathies are often diagnosed late or misclassified as other more common conditions, such as hypertrophic cardiomyopathy, hypertensive heart disease, ischemic or other forms of nonischemic cardiomyopathies. Accurate diagnosis is also critical because clinical features, testing methodologies, and approach to treatment vary significantly even within the different types of infiltrative cardiomyopathies on the basis of the type of substance deposited. Substantial advances in noninvasive cardiac imaging have enabled accurate and early diagnosis. thereby eliminating the need for endomyocardial biopsy in most cases. This scientific statement discusses the role of contemporary multimodality imaging of infiltrative cardiomyopathies, including echocardiography, nuclear and cardiac magnetic resonance imaging in the diagnosis, prognostication, and assessment of response to treatment.

Advanced CMR Techniques in Anderson-Fabry Disease: State of the Art

Anderson-Fabry disease (AFD) is a rare multisystem X-linked lysosomal storage disorder caused by α-galactosidase A enzyme deficiency. Long-term cardiac involvement in AFD results in left ventricular hypertrophy and myocardial fibrosis, inducing several complications, mainly arrhythmias, valvular dysfunction, and coronary artery disease. Cardiac magnetic resonance (CMR) represents the predominant noninvasive imaging modality for the assessment of cardiac involvement in the AFD, being able to comprehensively assess cardiac regional anatomy, ventricular function as well as to provide tissue characterization. This review aims to explore the role of the most advanced CMR techniques, such as myocardial strain, T1 and T2 mapping, perfusion and hybrid imaging, as diagnostic and prognostic biomarkers.

Inflammatory Fabry Cardiomyopathy Demonstrated Using Simultaneous [18F]-FDG PET-CMR

Using hybridized [¹⁸F]-fluorodeoxyglucose positron emission tomography with cardiac magnetic resonance, we identify active myocardial inflammation and demonstrate its relationship with late gadolinium enhancement, in Fabry disease. We demonstrate that late gadolinium enhancement represents, at least in part, active myocardial inflammation and identify an early inflammatory phenotype that may represent a therapeutic window before irreversible tissue injury and adaptation occur. (Level of Difficulty: Intermediate.).

Cardiovascular magnetic resonance native T1 mapping in Anderson-Fabry disease: a systematic review and meta-analysis

BACKGROUND

T1 mapping is an established cardiovascular magnetic resonance (CMR) technique that can characterize myocardial tissue. We aimed to determine the weighted mean native T1 values of Anderson-Fabry disease (AFD) patients and the standardized mean differences (SMD) as compared to healthy control subjects.

METHODS

A comprehensive literature search of the PubMed, Scopus and Web of Science databases was conducted according to the PRISMA statement to retrieve original studies reporting myocardial native T1 values in AFD patients and healthy controls. A random effects model was used to calculate SMD, and meta-regression analysis was conducted to explore heterogeneity sources. Subgroup analysis was also performed according to scanner field strength and sequence type.

RESULTS

From a total of 151 items, 14 articles were included in the final analysis accounting for a total population of 982 subjects. Overall, the weighted mean native T1 values was 984 ± 47 ms in AFD patients and 1016 ± 26 ms in controls (P < 0.0001) with a pooled SMD of - 2.38. In AFD patients there was an inverse correlation between native T1 values and male gender (P = 0.002) and left ventricular hypertrophy (LVH) (P < 0.001). Subgroup analyses confirmed lower T1 values in AFD patients compared to controls with a pooled SMD of -  2.54,  -  2.28, -   2.46 for studies performed on 1.5T with modified Look-Locker inversion recovery (MOLLI), shortened MOLLI and saturation-recovery single-shot acquisition, respectively and of -  2.41 for studies conducted on 3T.

CONCLUSIONS

Our findings confirm a reduction of native T1 values in AFD patients compared to healthy controls and point out that the degree of T1 shortening in AFD is influenced by gender and LVH. Although T1 mapping is useful in proving cardiac involvement in AFD patients, there is need to standardize shreshold values according to imaging equipment and protocols.