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Keywords
- Aortic Valve Stenosis
- Hypertensive Heart Disease
- Double Outlet Right Ventricle
- Adult Congenital Heart Disease
- Limb Girdle Muscular Dystrophy
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
Damus–Kaye–Stansel Operation
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Surgical operation performed in TGA, single ventricle, and restrictive VSD causing subaortic stenosis.
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Side-to-side aorta and pulmonary artery connection to provide unrestricted blood flow from the systemic ventricle to the aorta.
D-Dimers
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High negative predictive value for PE and DVT.
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Positive D-dimer results with medium–high clinical probability of PE should be followed by CTA.
Dextrocardia
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Anomalous cardiac position with the apex pointing the right chest wall.
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Cardiac anatomy may be normal.
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Check for other congenital cardiac lesions.
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Differential diagnosis: in case of abnormal heart position, look for congenital absence of pericardium.
Diastolic Dysfunction
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See section “Heart failure”.
Diastolic Tail
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See section “Aortic coarctation”.
DiGeorge Syndrome
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Genetic disease on chromosome 22 leading to thymic hypoplasia with low T cell count, hypoparathyroidism with hypocalcemia, and outflow tract defects of the heart (ToF, truncus arteriosus, interrupted aortic arch, right-sided aortic arch, aberrant right subclavian artery).
Dilated Cardiomyopathy
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Impaired systolic function with dilatation of cardiac chambers.
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Diastolic function can be normal or impaired.
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Causes: inherited (25 %), myocarditis, metabolic, nutritional, and persistent tachycardia. Usually diagnosis of exclusion.
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Differential diagnosis: ischemic heart disease, valvular disease, adult congenital heart disease, left ventricular noncompaction, iron-overloaded cardiomyopathy, alcoholic cardiomyopathy, hypertensive heart disease.
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See also section Cardiomyopathies.
Dipyridamole
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Indirect vasodilator agent used in stress MR.
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Increase endogenous levels of adenosine blocking cellular uptake.
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Dipyridamole dose: 0.56 mg/kg IV over 4 min.
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Prolonged action (~30 min).
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Low-dose protocol: infusion of a total dose of 0.56 mg/kg dipyridamole in 4 min, with imaging started immediately after completion of the 4 min infusion.
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High-dose protocol: adds a second injection of 0.28 mg/kg dipyridamole for 2-min duration, with imaging initiated at 8 min after the beginning of the first injection (a total dose of 0.84 mg/kg dipyridamole is injected in the high-dose dipyridamole infusion protocol).
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Patients should avoid methylxanthine-containing products for 24 h prior the scan.
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Contraindications: (1) high-grade AV block; (2) asthma or COPD; (3) sinus bradycardia; (4) systemic hypotension (BP <90 mmHg); (5) severe carotid stenosis.
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Side effects: transient heart block, transient hypotension, transient tachycardia, bronchospasm.
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Antagonist: aminophylline, 50–100 mg over 1 min, injection can be repeated up to 250 mg total dose.
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See also section “Perfusion imaging, myocardial”.
Dobutamine
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Positive inotropic agent used in stress MR.
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Increases heart rate and myocardial contractility.
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High-dose protocol: IV dobutamine infusion at 3 min stages (10, 20, 30, 40 μg/kg/min).
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Target heart rate: (220 age) × 0.85. If not reached at 40 μg/kg/min, atropine in 0.25 mg fraction (2 mg max.) if heart rate response is poor.
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Low-dose protocol: 5–10 μg/kg/min.
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Contraindications: (1) severe hypertension (>220/120 mmHg); (2) congestive heart failure; (3) unstable angina (4) aortic valve stenosis (peak gradient >50 mmHg); (5) HCM; (6) complex arrhythmias; (7) myocarditis; (8) pericarditis.
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See also section “Perfusion imaging, myocardial”.
Dominance, Coronary
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Coronary artery dominance refers to which artery supplies the posterior part of the heart.
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In 85–90 % is the right coronary artery (right dominance).
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In 8–10 % is the circumflex artery (left dominance).
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In 5 % the inferior wall is vascularized both from RCA and Cx (codominant or balanced circulation).
Dose Length Product
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DLP: CTDI vol × scan length.
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It is an indicator of total exposure for a complete CT scan, which allows us to compare the dose with several adjustments of technical parameters in order to optimize patient protection.
Double Outlet Right Ventricle
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>50 % of great vessels arise from the right ventricle.
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Large subaortic VSD.
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Wide abnormalities spectrum: from Fallot type to transposition of the great arteries.
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Can be associated with RVTO stenosis.
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MR: (1) vascular connection, (2) ventricular volumes and function, (3) RVTO stenosis, (4) shunts.
Dressler Syndrome
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A myocardial infarction-associated pericarditis with delayed onset typically 1 week after infarction to several months.
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Suspected autoimmune etiology.
Ductus Arteriosus or Ductus Botalli
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A fetal blood vessel connecting the pulmonary artery to the aortic arch.
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Fibrosis and closure at birth (ligamentum arteriosum).
Ductus Arteriosus, Persistent
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Left-to-right extracardiac shunt caused by patent ductus arteriosus.
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MR: (1) shunt detection; (2) quantification of shunt degree.
Dyslipidemia
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Primary hyperlipidemias: (1) familial hyperchylomicronemia; (2) familial hypercholesterolemia; (3) familial defective apoprotein B-100; (4) polygenic hypercholesterolemia; (5) familial combined hyperlipidemia; (6) dysbetalipoproteinemia; (7) familial hypertriglyceridemia; (8) type V hyperlipoproteinemia.
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Secondary hyperlipidemias: (1) renal failure; (2) nephrotic syndrome; (3) hypothyroidism; (4) type II diabetes and obesity; (5) alcohol abuse; (6) cholestasis; (7) drugs.
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Normal range for plasma lipid levels: (1) total cholesterol, 150–250 mg/dL; (2) LDL cholesterol, <160 mg/dL; (3) HDL cholesterol, 30–75 mg/dL; (4) triglycerides, 70–175 mg/dL.
Dyssynchrony, Cardiac
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Three types: (1) atrioventricular (PR > 120 ms); (2) interventricular (delay between RV and LV contraction); (3) intraventricular (differences in regional wall motion).
Dystrophies, Muscular
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Hereditary muscle disease causing progressive severe skeletal muscle weakness, which can lead to dilated cardiomyopathy.
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Most common: Duchenne, Becker, limb girdle muscular dystrophies.
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MR: (1) left ventricle dysfunction; (2) myocardial edema and inflammation; (3) late enhancement similar to myocarditis.
Suggested Reading
Khoo JP et al (2012) Stress cardiovascular MR in routine clinical practice: referral patterns, accuracy, tolerance, safety and incidental findings. Br J Radiol 85:e851–e857
Mavrogeni S et al (2013) CMR detects subclinical cardiomyopathy in mother-carriers of duchenne and becker muscular dystrophy. JACC Cardiovasc Imaging 6:526–528
Quarta G et al (2011) Cardiomyopathies: focus on cardiovascular magnetic resonance. Br J Radiol 84:S296–S305
Warnes CA et al (2008) ACC/AHA 2008 guidelines for the management of adults with congenital heart disease. Circulation 118:e714–e833
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De Cecco, C.N., Rengo, M. (2014). D. In: MDCT and MRI of the Heart. A-Z Notes in Radiological Practice and Reporting. Springer, Milano. https://doi.org/10.1007/978-88-470-2865-4_4
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DOI: https://doi.org/10.1007/978-88-470-2865-4_4
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