ABSTRACT
Cardiovascular magnetic resonance imaging (CMR) has become a routinely used imaging modality for congenital heart disease. A CMR examination allows the assessment of thoracic anatomy, global and regional cardiac function, blood flow in the great vessels and myocardial viability and perfusion. In the clinical routine cardiovascular MRI is mostly performed at field strengths of 1.5 Tesla (T). Recently, magnetic resonance systems operating at a field strengths of 3 T became clinically available and can also be used for cardiovascular MRI. The main advantage of CMR at 3 T is the gain in the signal-to-noise ratio resulting in improved image quality and/or allowing higher acquisition speed. Several further differences compared to MRI systems with lower field strengths have to be considered for practical applications. This article describes the impact of CMR at 3 T in patients with congenital heart disease by meanings of methodical considerations and case studies.
Subject(s)
Heart Defects, Congenital/pathology , Image Enhancement/methods , Magnetic Resonance Imaging/methods , Myocardium/pathology , Adult , Child , HumansABSTRACT
In today's clinical practice cardiovascular magnetic resonance (CMR) imaging is increasingly used for assessment of congenital and acquired heart disease in children. CMR complements echocardiography and provides a noninvasive alternative to diagnostic cardiac catheterization. In contrast to echocardiography, CMR is not limited by acoustic windows, and unlike cardiac catheterization, CMR lacks ionizing radiation. Contiguous three and four dimensional data sets allow to display cardiac and thoracic vessel anatomy in any desired imaging plane. These characteristics provide unique images for the complete depiction of the pathological anatomy in particular in congenital heart disease. Furthermore CMR is also used for assessment of cardiac function, blood-flow measurements, tissue characterization, and, more recently, for evaluation of myocardial perfusion and viability. The following article reviews CMR indications in pediatric cardiology by means of clinical examples.
Subject(s)
Cardiomyopathies/diagnosis , Heart Defects, Congenital/diagnosis , Heart Neoplasms/diagnosis , Image Processing, Computer-Assisted , Imaging, Three-Dimensional , Magnetic Resonance Angiography , Magnetic Resonance Imaging , Adolescent , Child , Child, Preschool , Echocardiography , Female , Humans , Infant , Male , Marfan Syndrome/diagnosis , Mucocutaneous Lymph Node Syndrome/diagnosis , Sensitivity and SpecificityABSTRACT
Acquired von Willebrand syndrome is a rare bleeding disorder associated with other primary diseases such as cardiovascular disorders which can cause severe haemorrhage during surgery or interventional procedures. It should be suspected if there is no history of bleeding and abnormal von Willebrand factor (VWF) values in patients with predisposing disorders. We present two children with congenital heart defects and no personal or family history of bleeding. In these patients we preoperative diagnosed acquired von Willebrand syndrome with coagulation tests including analysis of the VWF multimeric pattern.
Subject(s)
Heart Defects, Congenital/physiopathology , von Willebrand Diseases/etiology , Adolescent , Child , Female , Humans , von Willebrand Factor/analysisABSTRACT
Forty years after the introduction of sagittal split osteotomy for transposition of the mandible according to Obwegeser, very different procedures for osteosynthesis are still discussed and practised. In a simple biomechanical model in the porcine mandible, five different methods for osteosynthesis using metallic screws (titanium, cobalt-chromium-molybdenum alloy) and one using a polymer screw (polylactic acid-copolymer blend), as well as the use of miniplates, were studied with regard to the stability of the compound. The Kruskal-Wallis H-test (variance analysis by ranks) showed statistically highly significant differences (P = 0.00017) regarding maximum stability. Osteosynthesis by miniplates was very stable with regard to the maximum load (Fmax = 234 N +/- 47), but not so in terms of three-dimensional stability of the osteosynthesis itself. The highest stability of osteosynthesis with screws only (Fmax = 183 N +/- 65) was found for a 2.7-mm titanium screw in triangular geometry. The use of 2.7-mm cobalt-chromium-molybdenum screws (Fmax = 173 N +/- 42) and 3.5-mm titanium screws (Fmax = 160 N +/- 76) did not make an statistical difference (P = 0.37). The mechanical values of 2.0-mm titanium screws in linear (Fmax = 113 N +/- 37) or triangular (Fmax = 136 N +/- 62) geometry and of 3.5-mm polylactic acid-copolymer blend screws (Fmax = 121 N +/- 33) did not differ statistically from each other (P = 0.75) but they did from the previous group (P = 0.019). In consideration of the low biting forces following sagittal split osteotomy, all tested procedures of osteosynthesis meet the mechanical requirements for clinical practice.