Magnetic resonance imaging of the transplanted pediatric heart as a potential predictor of rejection

AIM To evaluate cardiac magnetic resonance imaging(CMR) as a non-invasive tool to detect acute cellular rejection(ACR) in children after heart transplant(HT).METHODS Thirty pediatric HT recipients underwent CMR at the time of surveillance endomyocardial biopsy(EMB) and results were compared to 14 non-transplant controls. Biventricular volumes, ejection fractions(EFs), T2-weighted signal intensities, native T1 times, extracellular volumes(ECVs) and presence of late gadolinium enhancement(LGE) were compared between patients and controls and betweenpatients with International Society of Heart and Lung Transplantation(ISHLT) grade ≥ 2R rejection and those with grade 0/1R. Heart rate(HR) and brain natriuretic peptide(BNP) were assessed as potential biomarkers.RESULTS Significant ACR(ISHLT grade ≥ 2R) was an infrequent event in our population(5/30, 17%). Ventricular volumes,EFs, LGE prevalence, ECVs, native T1 times, T2 signal intensity ratios, HR and BNP were not associated with the presence of ≥ 2R ACR.CONCLUSION In this pilot study CMR did not reliably identify ACRrelated changes in pediatric HT patients.

Disharmonious Ventricular Relationship and Topology for the Given Atrioventricular Connections.Contemporary Diagnostic Approach Using 3D Modeling and Printing

In the last issue,two case reports separately present examples of the extremely rare and complex congenital heart diseases that show concordant atrioventricular connections to the L-looped ventricles in the presence of situs solitus.Both cases highlight that the relationship between the two ventricles within the ventricular mass is not always harmonious with the given atrioventricular connection.Such disharmony between the connections and relationships requires careful assessment of the three basic facets of cardiac building blocks,namely their morphology,the relationship of their component parts,and their connections with the adjacent segments.3D imaging and printing can now facilitate an otherwise difficult diagnosis in such complex situations.Rotation of either the 3D images or the models permit accurate assessment of the ventricular topologic pattern by creating the right ventricular en-face septal view,thus facilitating placement of the observer’s hands.As we now emphasize,an alternative approach,which might prove more attractive to imagers,is to rotate the ventricular mass to provide the ventricular apical view,thus permitting determination of the ventricular relationship without using the hands.

New Insights into Sinus Venosus Defects from Cross-Sectional Imaging

Sinus venosus defects include two varieties,superior and inferior sinus venosus defects.The superior sinus venosus defect is characterized by abnormal communication between two closely related venoatrial structures:1)the normally positioned superior vena cava-right atrium complex and 2)the right pulmonary vein-left atrium complex that is displaced leftward,forward and upward.Inferior sinus venosus defects primarily involve the inferior vena cava-right atrial junction while the right pulmonary vein-left atrial junction can also be affected.Because of the rarity and wide variation of the defects,the morphological characterization of sinus venosus defects is inconsistent among investigators and often inaccurate.Modern imaging technologies with high spatial and temporal resolutions have allowed accurate and detailed assessment of the pathological anatomy in larger numbers of cases.In this pictorial essay,we revisit the established and controversial features of the sinus venous defects using twodimensional(2D)and three-dimensional(3D)images obtained by magnetic resonance(MR)or computed tomography(CT)with brief discussion on imaging and treatment strategies.

Characterization of Malalignment between Atrial and Ventricular Septa in Overriding/Straddling Tricuspid and Mitral Valves

Objective:Overriding/straddling of an atrioventricular valve is a consequence of atrial-ventricular septal malalignment.We sought to characterize the malalignment by analogizing it to a flap-door and using structured approach.Methods:The echocardiograms and magnetic resonance images of 35 patients with overriding/straddling tricuspid or mitral valve were evaluated to assess the following modifiers;the malaligned part of the septum,the reference structure,and the mechanism,direction and severity of malalignment.Results:The pathology included classic overriding tricuspid valve in 15,classic overriding mitral valve in 12,and overriding tricuspid valve with left juxtaposition of atrial appendages in 8.In classic overriding tricuspid valve,the ventricular septum was hinged to the anterior interventricular groove and its insertion to the posterior interventricular groove was displaced toward the right ventricle.The VSD primarily involved the inlet but also extended toward the anterior interventricular groove.In classic overriding mitral valve,the ventricular septum was hinged to the posterior interventricular groove and crux cordis.Its insertion to the anterior interventricular groove was displaced toward the left ventricle.The VSD primarily involved the anterior part but also extended toward the inlet.Overriding tricuspid valve with left juxtaposition of atrial appendages had a mild degree of malalignment with displacement/rotation of the atrioventricular junction.Evenly spaced short-axis images were most helpful in characterizing the pathology.Conclusions:Overriding/straddling atrioventricular valves can be easily understood by analogizing the atrial-ventricular septal malalignment to a flap-door and describing the pathology in a structured manner.Contrary to what has previously been known,the VSD is not limited to the inlet or outlet part of the ventricular septum.