Automatic detection of left and right ventricles from CTA enables efficient alignment of anatomy with myocardial perfusion data.

BACKGROUND: Accurate alignment between cardiac CT angiographic studies (CTA) and nuclear perfusion images is crucial for improved diagnosis of coronary artery disease. This study evaluated in an animal model the accuracy of a CTA fully automated biventricular segmentation algorithm, a necessary step for automatic and thus efficient PET/CT alignment. METHODS AND RESULTS: Twelve pigs with acute infarcts were imaged using Rb-82 PET and 64-slice CTA. Post-mortem myocardium mass measurements were obtained. Endocardial and epicardial myocardial boundaries were manually and automatically detected on the CTA and both segmentations used to perform PET/CT alignment. To assess the segmentation performance, image-based myocardial masses were compared to experimental data; the hand-traced profiles were used as a reference standard to assess the global and slice-by-slice robustness of the automated algorithm in extracting myocardium, LV, and RV. Mean distances between the automated and the manual 3D segmented surfaces were computed. Finally, differences in rotations and translations between the manual and automatic surfaces were estimated post-PET/CT alignment. The largest, smallest, and median distances between interactive and automatic surfaces averaged 1.2 ± 2.1, 0.2 ± 1.6, and 0.7 ± 1.9 mm. The average angular and translational differences in CT/PET alignments were 0.4°, -0.6°, and -2.3° about x, y, and z axes, and 1.8, -2.1, and 2.0 mm in x, y, and z directions. CONCLUSIONS: Our automatic myocardial boundary detection algorithm creates surfaces from CTA that are similar in accuracy and provide similar alignments with PET as those obtained from interactive tracing. Specific difficulties in a reliable segmentation of the apex and base regions will require further improvements in the automated technique.

The effects of adenocaine (adenosine and lidocaine) on early post-resuscitation cardiac and neurological dysfunction in a porcine model of cardiac arrest.

AIM: Return of spontaneous circulation (ROSC) elicits ischaemia/reperfusion injury and myocardial dysfunction. The combination of adenosine and lidocaine (AL, adenocaine) has been shown to (1) inhibit neutrophil inflammatory activation and (2) improve left ventricular function after ischaemia. We hypothesized that resuscitation with adenocaine during early moments of cardiopulmonary resuscitation (CPR) attenuates leucocyte oxidant generation and myocardial dysfunction. METHODS: Pigs were randomized to: (1) sham (n=7), (2) cardiac arrest (CA; n=16), or 3) cardiac arrest+adenocaine (CA+AL; n=12). After 7 min of electrically induced ventricular fibrillation, start of CPR was followed by infusion of saline (CA) or adenocaine (CA+AL) for 6 min. Haemodynamics, cardiodynamics (pressure-volume loops) and leucocyte superoxide anion generation were assessed. Neurological function was evaluated after 24h by histology and neurological deficit score (0=normal; 500=brain dead). RESULTS: Rate of ROSC was comparable between groups: CA group 11/16 and CA+AL group 7/12 p=0.57). Cardiac index transiently increased after ROSC in both groups. Left ventricular dysfunction demonstrated by a rightward shift of the intercept of end-systolic pressure-volume relations in CA was avoided in the CA+AL group. Leucocyte superoxide anion generation 2h after ROSC was significantly attenuated in the CA+AL group compared to the CA group. Neurological deficit scores [CA: median: 17.5(IQR:0-75) and CA+AL: 35(IQR:15-150)] and histopathological damage were comparable in both groups (p=0.37). CONCLUSION: Infusion of adenocaine during early resuscitation from CA significantly improved early post-resuscitation cardiac function and attenuated leucocyte superoxide anion generation, without a change in post-ROSC neurological function. (IACUC protocol number 023-2009).