Usefulness of Magnetic Resonance Imaging for the Diagnosis of Right Ventricular Dysplasia in Children
Division of Cardiology, Department of Pediatrics, The Children's Hospital of Philadelphia, The University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA. The American Journal of Cardiology
(Impact Factor: 3.28).
05/2006; 97(8):1232-7. DOI: 10.1016/j.amjcard.2005.11.045
Cardiac magnetic resonance (CMR) has been helpful in adults in the diagnosis of arrhythmogenic right ventricular dysplasia. Short of direct surgical observation or autopsy, no gold standard exists. CMR diagnostic criteria include right atrial and ventricular dilation, regional right ventricular (RV) wall motion abnormalities, outflow tract ectasia, and myocardial fatty infiltration. To determine whether adult diagnostic criteria are useful in children referred for CMR for this diagnosis, the images and records of 81 patients (aged 11.5 +/- 5.5 years) over an 8-year period were reviewed. Histories included ventricular tachycardia, palpitations, dilated right ventricle, syncope, near sudden death, or family history of RV dysplasia. Four families were studied with parents who had RV dysplasia diagnosed by surgery, explanted heart, or CMR. CMR imaging included T1-weighted imaging, cine, 1-dimensional RV myocardial tagging, and phase-encoded velocity mapping, and 2 patients underwent delayed-enhancement CMR. Only 1 of the 81 patients met 5 of the criteria. None of the others met >2 of the criteria, and only 2 patients met 1 or 2 criteria. For questionable regional wall motion abnormalities, RV myocardial tagging was helpful. In conclusion, CMR of patients with a history suspicious for the diagnosis of RV dysplasia is a low-yield test in children. This may be due to the evolving nature of the disease, which does not manifest itself from a morphologic or ventricular-function standpoint until later in development. Follow-up studies as patients age may be advantageous.
Available from: Robert Murray Hamilton
- "The most recent report of the North American Multidisciplinary Study of ARVC/D showed a disappointingly low diagnostic performance of MRI compared with other diagnostic tests, including echocardiography and angiography.17) The diagnostic yield of MRI for ARVC/D is significantly lower in the pediatric age group than in adults.43) In fact, it needs to be determined whether MRI is a cost-effective test for the diagnosis of ARVC/D in children and whether the MRI protocol and criteria used for adults are equally applicable to children. "
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ABSTRACT: Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a genetically determined disease that progresses continuously from conception and throughout life. ARVC/D manifests predominantly in young adulthood. Early identification of the concealed cases in childhood is of utmost importance for the prevention of sudden cardiac death later in life. Magnetic resonance imaging (MRI) is routinely requested in patients with a confirmed or suspected diagnosis of ARVC/D and in family members of the patients with ARVC/D. Although the utility of MRI in the assessment of ARVC/D is well recognized in adults, MRI is a low-yield test in children as the anatomical, histological, and functional changes are frequently subtle or not present in the early phase of the disease. MRI findings of ARVC/D include morphologic changes such as right ventricular dilatation, wall thinning, and aneurismal outpouchings, as well as abnormal tissue characteristics such as myocardial fibrosis and fatty infiltration, and functional abnormalities such as global ventricular dysfunction and regional wall motion abnormalities. Among these findings, regional wall motion abnormalities are the most reliable MRI findings both in children and adults, while myocardial fibrosis and fat infiltration are rarely seen in children. Therefore, an MRI protocol should be tailored according to the patient's age and compliance, as well as the presence of other findings, instead of using the protocol that is used for adults. We propose that MRI in children with ARVC/D should focus on the detection of regional wall motion abnormalities and global ventricular function by using a cine imaging sequence and that the sequences for myocardial fat and late gadolinium enhancement of the myocardium are reserved for those who show abnormal findings at cine imaging. Importantly, MRI should be performed and interpreted by experienced examiners to reduce the number of false positive and false negative readings.
Available from: Christopher K Macgowan
- "In the right ventricle (RV), even transmural fibrosis may only be < 2 mm thick. Moreover, LGE is rare in pediatric ARVD patients and, if present, subtle. For these reasons, an optimal contrast-to-noise ratio between normal and fibrotic myocardium is even more important than for the LV myocardium. "
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ABSTRACT: It has been suggested that, in late gadolinium enhancement, the signal of right ventricular myocardium is nulled at a shorter inversion time than the left. While we initially made the same observation, we believe that the difference is not real, but results from artifacts.
We present 7 cases as well as computer simulations to describe the nature of these artifacts and explain how they can create the impression of different inversion times for the right and left ventricle. At inversion times that are shorter than ideal for the myocardium a black rim can be seen at the border of the myocardium with blood on the inside and with fat on the outside. This is most likely a partial volume effect. The thin myocardium of the right ventricle is sandwiched between these black rims and, at a low spatial resolution, is no longer visible. In this case, the adjacent black rims may then be misinterpreted as myocardium. While black rims also occur on the left side, the myocardium is thicker and remains discernable as a separate layer. As a consequence, the optimal inversion time for the right ventricle only appears different from that for the left. In fact, in the presence of hypertrophy of the right ventricle or during systolic wall thickening we did not find a difference in inversion times between the left and right ventricle. We conclude that sufficient spatial resolution is important for adequate late gadolinium enhancement of the right ventricle.
Available from: digitalcorpora.org
- "Cardiac MRI in children has not demonstrated an increased ability to detect early changes of ARVD; however, this could be the result of the disease not manifesting at earlier ages [Fogel et al 2006]. Further studies are needed. "
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ABSTRACT: Autosomal dominant arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is characterized by progressive fibrofatty replacement of the myocardium that predisposes to ventricular tachycardia and sudden death in young individuals and athletes. It primarily affects the right ventricle; with time, it may also involve the left ventricle. The presentation of disease is highly variable even within families, and affected individuals may not meet established clinical criteria. The mean age at diagnosis is 31 years (±13; range: 4-64 years).
The diagnosis of autosomal dominant ARVD/C is made using a combination of noninvasive and invasive tests to detect abnormalities in cardiac structure and rhythm. The eight genes known to be associated with autosomal dominant ARVD/C are: TGFB3 (locus name: ARVD1; protein: transforming growth factor beta-3), RYR2 (locus name ARVD2; protein: ryanodine receptor 2), TMEM43 (locus name ARVD5; protein: transmembrane protein 43), DSP (locus name ARVD8; protein: desmoplakin), PKP2 (locus name ARVD9; protein: plakophilin-2), DSG2 (locus name: ARVD10; protein: desmoglein-2), DSC2 (locus name: ARVD11; protein: desmocollin-2), and JUP (locus name: ARVD12; protein: junction plakoglobin). Four additional genes associated with autosomal dominant ARVD/C have been mapped but not identified (locus names ARVD3, ARVD4, ARVD6, and ARVD7). Additional loci remain undetermined. Molecular genetic testing is available on a clinical basis for TGFB3, RYR2, TMEM43, DSP, PKP2, DSG2, DSC2, and JUP.
Treatment of manifestations: Management is individualized and focused on prevention of syncope, cardiac arrest, and sudden death through use of antiarrhythmic medication, implantable cardioverter-defibrillators, and rarely, heart transplantation. Individuals who present with clinical signs of right heart failure and/or left ventricular dysfunction and have a history of ventricular tachycardia should be treated aggressively. Testing of relatives at risk: screening by noninvasive tests annually during puberty and every two to three years after puberty.
Autosomal dominant ARVD/C is inherited in an autosomal dominant manner. A proband with autosomal dominant ARVD/C may have the disorder as a result of a new gene mutation. The proportion of cases caused by de novo mutations is unknown. Each child of an individual with autosomal dominant ARVD/C has a 50% chance of inheriting the mutation. Prenatal diagnosis for pregnancies at increased risk is possible if the disease-causing mutation has been identified in the family; if no laboratory offering prenatal testing is listed in the GeneTests Laboratory Directory, such testing may be available through laboratories offering custom prenatal testing.
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