Microcomputed Tomography Provides High Accuracy Congenital Heart Disease Diagnosis in Neonatal and Fetal Mice

Abstract

Background Mice are well suited for modeling human congenital heart defects (CHD), given their four-chamber cardiac anatomy. However, mice with CHD invariably die prenatally/neonatally, causing CHD phenotypes to be missed. Therefore, we investigated the efficacy of noninvasive micro-computed tomography (micro-CT) to screen for CHD in stillborn/fetal mice. These studies were carried out using chemically mutagenized mice expected to be enriched for birth defects including CHD. Methods and Results Stillborn/fetal mice obtained from the breeding of N-ethyl-N-nitrosourea (ENU) mutagenized mice were formalin-fixed and stained with iodine, then micro-CT scanned. Those diagnosed with CHD and some CHD-negative pups were necropsied. A subset of these were further analyzed by histopathology to confirm the CHD/no-CHD diagnosis. Micro-CT scanning of 2105 fetal/newborn mice revealed an abundance of ventricular septal defects (VSD) (n=307). Overall, we observed an accuracy of 89.8% for VSD diagnosis. Outflow tract anomalies identified by micro-CT included double outlet right ventricle (n=36), transposition of the great arteries (n=14), and persistent truncus arteriosus (n=3). These were diagnosed with a 97.4% accuracy. Aortic arch anomalies also were readily detected with an overall 99.6% accuracy. This included right aortic arch (n=28) and coarctation/interrupted aortic arch (n=12). Also detected by micro-CT were atrioventricular septal defects (n=22), tricuspid hypoplasia/atresia (n=13), and coronary artery fistulas (n=16). They yielded accuracies of 98.9%, 100%, and 97.8% respectively. Conclusions Contrast enhanced micro-CT imaging in neonatal/fetal mice can reliably detect a wide spectrum of CHD. We conclude micro-CT imaging can be used for routine rapid assessments of structural heart defects in fetal/newborn mice.

Interrogating Congenital Heart Defects With Noninvasive Fetal Echocardiography in a Mouse Forward Genetic Screen

“…These findings are similar to those reported in human fetal ultrasound studies 8 . Comparison of CHD diagnosis achieved with Vevo2100 vs. post-mortem micro-CT imaging showed similar high diagnostic accuracy for most CHDs, except for aortic arch anomalies and situs defects 9 . Current UBM technology cannot visualize the small aortic arch vessels, but these can be detected by contrast enhanced micro-CT 9 .…”

Tricaprin Rescues Myocardial Abnormality in a Mouse Model of Triglyceride Deposit Cardiomyovasculopathy

“…Washout rates WORs , used to evaluate LCFA metabolism, were calculated from the formula BMIPP uptake 1 h -remaining BMIPP 4 h / BMIPP uptake 1 h . 2.3.2 Measurements of myocardial lipid deposition and left ventricular ejection fraction LVEF by CT Micro-CT has been used to measure cardiac function in rodents 25,26 . In the present experiment, micro-CT Latheta LCT-200, Hitachi-Aloka Medical, Tokyo, Japan was used to measure cardiac lipid deposition and function in the mouse heart.…”

Characterization of Regional Deformation and Material Properties of the Intact Explanted Vein by microCT and Computational Analysis

“…The results above demonstrate that, an accordingly optimized protocol (Figure 3), recently developed iodine tissue-staining techniques [21], [22] can also be applied on the explanted vein. The staining pretreatment allowed the vessel's morphology (Figure 5) and function, like deformation (Figures 4 and 6), to be evaluated in 3D and high-resolution using microCT and the appropriate testing apparatus.…”

“…Although the relationship between pretreatment with Lugol's solution and soft tissue contrast has been established in previous micro-CT visualization of embryonic and cardiovascular tissues [21], [22], the protocol needs to be optimized for vein specimens. To this end, the subcutaneous abdominal vein sample was divided into eleven 3-mm-long sections, and one section was soaked in each 0, 5, 10 or 20% Lugol's solution (cat# 26385-06, Electron Microscopy Sciences, USA) for 1.0, 2.0, or 3.0 h. The start times of the different soaking procedures were timed such that the sections could be imaged together.…”

“…Although computed tomography (CT) provides the highly desirable combination of spatial resolution, image quality and acquisition speed, it has been seldom utilized due to its limited soft-tissue contrast. However, in light of recent advances in specimen staining techniques that make otherwise undetectable details of tissues visible [21], [22], CT-based deformation measurements are now conceptually feasible and worth exploring. The 3D feature offered by CT is especially desirable as basis for comprehensive mechanical analysis, since the morphology and, thus, mechanical responses of veins occur in all spatial directions.…”