Fusion of imaging technologies: how, when, and for whom?

Proposal for a Display Method for Myocardial Single Photon Emission Computed Tomography Based on Left Ventricular Volume

Bull's eye view for the display of myocardial single-photon emission computed tomography (SPECT) 3-D perfusion maps does not reflect left ventricular (LV) volume, an important parameter. We created and evaluated a myocardial SPECT display method that reflects the LV volume.Using Digital Imaging and Communications in Medicine data, short-axis slices from the apex to the base were reconstructed and interpolated into 0.5-mm thickness. We obtained the radial lengths at 1° intervals throughout 360°, and calculated the length of the LV long axis and half circumference (1/2 circ). Myocardial perfusion was displayed as 2 ellipsoidal developments that exhibited the left anterior descending coronary artery (LAD) and non-LAD regions. We created a system that can display these processes on a personal computer. Myocardial SPECT data from 526 individuals without heart disease were analyzed. The long axis and 1/2 circ were compared with the body size, LV end-diastolic diameter (LVDd) obtained by echocardiography, and the end-diastolic volume (EDV) obtained by electrocardiogram-gated SPECT analysis. The 1/2 circle correlated with the LVDd and EDV. The images obtained allowed a diagnosis comparable to that made using the conventional coordinate display system.The new myocardial display reflects ischemia and LV volume within a single image, which cannot be achieved with conventional SPECT image display. Additional studies of this display system are required to allow its application to patients with heart disease.

High incidence of newly diagnosed obstructive coronary artery disease regardless of chest pain detected on pre-procedural cardiac computed tomography angiography in patients undergoing atrial fibrillation ablation

BACKGROUND

Cardiac computed tomography (CT) is often performed before catheter ablation of atrial fibrillation to map atrial and pulmonary anatomy. Incident coronary artery disease (CAD) may also be diagnosed during cardiac CT angiography (CTA). Our aim was to assess whether coronary CTA might be able to identify a significant proportion of patients with obstructive CAD prior to their catheter ablation procedure event, even in asymptomatic patients.

METHODS

Consecutive patients undergoing pre-ablation coronary CTA for atrial fibrillation between 2013 and 2020 were retrospectively selected. Patients with previously diagnosed CAD were excluded. Obstructive CAD was defined as ≥50% luminal stenosis. We analyzed the relationship between obstructive CAD, any chest pain, and traditional risk factors.

RESULTS

Overall, 2321 patients [median age 63.0 (54.4-69.2), 1052/2321 (45.3%) female] underwent coronary CTA and 488/2321 (21.0%) were diagnosed with obstructive CAD. There was no difference regarding the rate of obstructive CAD in patients with any chest pain compared to patients without any chest pain [91/404 (22.5%) vs. 397/1917 (20.7%), P = 0.416, respectively). The following parameters were associated with obstructive CAD: age > 65 years [odds ratio (OR) = 2.51; 95% confidence interval (CI), 2.02-3.13; P < 0.001), male sex (OR = 1.59; 95% CI, 1.28-1.98; P < 0.001), hypertension (OR = 1.40; 95% CI, 1.08-1.81; P = 0.012), diabetes (OR = 1.50; 95% CI, 1.13-1.99; P = 0.006), dyslipidaemia (OR = 1.33; 95% CI, 1.07-1.66; P = 0.011) and history of smoking (OR = 1.34; 95% CI, 1.07-1.68; P = 0.011).

CONCLUSIONS

The high prevalence of obstructive CAD even in patients without chest pain highlights the importance of additional coronary artery diagnostics in patients undergoing left atrial CTA awaiting catheter ablation for atrial fibrillation. These patients regardless of chest pain thus may require further risk modification to decrease their potential ischemic and thromboembolic risk.

Three-dimensional simulation of pancreatic surgery showing the size and location of the main pancreatic duct

PURPOSE

We performed three-dimensional (3D) surgical simulation of pancreatic surgery, including the size and location of the main pancreatic duct on the resected pancreatic surface.

METHODS

The subjects of this retrospective analysis were 162 patients who underwent pancreatic surgery. This cohort was sequentially divided into a "without-3D" group (n = 81) and a "with-3D" group (n = 81). We compared the pancreatic duct diameter and its location, using nine sections in a grid pattern, with the intraoperative findings. The perioperative outcomes were also compared between patients who underwent pancreaticoduodenectomy (PD) and those who underwent distal pancreatectomy (DP).

RESULTS

There were no significant differences in the main pancreatic duct diameter between the 3D-simulated values and the operative findings. The 3D-simulated main pancreatic duct location was consistent with its actual location in 80 % of patients (65/81). In comparing the PD and DP groups, the intraoperative blood loss was 1174 ± 867 and 817 ± 925 ml in the without-3D group, and 828 ± 739 and 307 ± 192 ml in the with-3D group, respectively (p = 0.024, 0.026).

CONCLUSION

The 3D surgical simulation provided useful information to promote our understanding of the pancreatic anatomy, including details on the size and location of the main pancreatic duct.

Advanced Mapping Systems To Guide Atrial Fibrillation Ablation: Electrical Information That Matters

Catheter ablation is an established and widespread treatment for atrial fibrillation (AF). Contemporary electroanatomical mapping systems (EAMs) have been developed to facilitate mapping processes but remain limited by spatiotemporal and processing restrictions. Advanced mapping systems emerged from the need to better understand and ablate complex AF substrate, by improving the acquisition and illustration of electrophysiological information. In this review, we present you the recently advanced mapping systems for AF ablation in comparison to the established contemporary EAMs.

Electroanatomical mapping of atrial fibrillation: Review of the current techniques and advances

The number of atrial fibrillation (AF) catheter ablations performed annually has been increasing exponentially in the western countries in the last few years. This is clearly related to technological advancements, which have greatly contributed to the improvements in catheter ablation of AF. In particular, state-of-the-art electroanatomical mapping systems have greatly facilitated mapping processes and have enabled complex AF ablation strategies. In this review, we outline contemporary and upcoming electroanatomical key technologies focusing on new mapping tools and strategies in the context of AF catheter ablation.

Role of cardiac computed tomography and cardiovascular magnetic resonance imaging in guiding management and treatment of patients with atrial fibrillation: state of the art review

Atrial fibrillation (AF) is the most common arrhythmia in clinical practice and is associated with high morbidity and mortality. In view of an aging population, the prevalence and incidence of AF are on the rise and are expected to double in the coming decades, posing a huge economic burden on already strained resources. New innovative therapies such as pulmonary vein isolation and percutaneous closure of the left atrial appendage have emerged. The current applications of such therapies would not have been possible without the pivotal role of multimodality cardiovascular imaging. The role of echocardiography in guiding therapy has been extensively reviewed. However, there are new data in support of other complementary imaging modalities, mainly cardiac computed tomography and cardiovascular magnetic resonance imaging, which will be the focus of this review.

A novel preoperative fusion analysis using three-dimensional MDCT combined with three-dimensional MRI for patients with hilar cholangiocarcinoma

The purpose of the present study was to evaluate the anatomical relationship between the tumor, portal veins, hepatic arteries, and hilar hepatic ducts at the hepatic hilum using a novel preoperative fusion analysis for patients with hilar cholangiocarcinoma. This involved combining three-dimensional multidetector-row computed tomography with three-dimensional magnetic resonance imaging. This novel fusion imaging technique can play an important clinical role for patients undergoing surgery for hilar cholangiocarcinoma.

Personalized nanomedicine advancements for stem cell tracking

Recent technological developments in biomedicine have facilitated the generation of data on the anatomical, physiological and molecular level for individual patients and thus introduces opportunity for therapy to be personalized in an unprecedented fashion. Generation of patient-specific stem cells exemplifies the efforts toward this new approach. Cell-based therapy is a highly promising treatment paradigm; however, due to the lack of consistent and unbiased data about the fate of stem cells in vivo, interpretation of therapeutic effects remains challenging hampering the progress in this field. The advent of nanotechnology with a wide palette of inorganic and organic nanostructures has expanded the arsenal of methods for tracking transplanted stem cells. The diversity of nanomaterials has revolutionized personalized nanomedicine and enables individualized tailoring of stem cell labeling materials for the specific needs of each patient. The successful implementation of stem cell tracking will likely be a significant driving force that will contribute to the further development of nanotheranostics. The purpose of this review is to emphasize the role of cell tracking using currently available nanoparticles.

Role of Cardiac Imaging (CT/MR) Before and After RF Catheter Ablation in Patients with Atrial Fibrillation

Pre-procedure X-ray computed tomography (CT) and magnetic resonance imaging (MRI) angiography are commonly used to delineate the complex and variable relationship of the left atrium, pulmonary veins, and surrounding structures. 3D CT and MR angiography are routinely incorporated into electroanatomic mapping systems to guide ablation lesion placement in the context of patient specific anatomy. Post-procedure CT and MRI have also proven useful for evaluating complications such as pulmonary vein stenosis. In the future, these imaging modalities may be used to visualize more detailed tissue characteristics such as atrial fibrosis and ablation lesions. This could improve selection of patients for different treatment strategies and perhaps guide more effective ablation. This review will discuss current and emerging applications of CT and MRI before and after radiofrequency catheter ablation of atrial fibrillation.

Robotics and imaging in congenital heart surgery

The initial success seen in adult cardiac surgery with the application of available robotic systems has not been realized as broadly in pediatric cardiac surgery. The main obstacles include extended set-up time and complexity of the procedures, as well as the large size of the instruments with respect to the size of the child. Moreover, while the main advantage of robotic systems is the ability to minimize incision size, for intracardiac repairs, cardiopulmonary bypass is still required. Catheter-based interventions, on the other hand, have expanded rapidly in both application as well as the complexity of procedures and lesions being treated. However, despite the development of sophisticated devices, robotic systems to aid catheter procedures have not been commonly applied in children. In this article, we describe new catheter-like robotic delivery platforms, which facilitate safe navigation and enable complex repairs, such as tissue approximation and fixation, and tissue removal, inside the beating heart. Additional features including the tracking of rapidly moving tissue targets and novel imaging approaches are described, along with a discussion of future prospects for steerable robotic systems.