Anatomical investigation of the sinus node artery using dual-source computed tomography

Understanding Cardiac Anatomy and Imaging to Improve Safety of Procedures: The Sinus Node Artery

The sinus node artery can originate from either the right or the left coronary arteries, or even both, and follows a variable course. Being aware of these important variations is of clinical significance during open heart surgery and catheter ablation procedures to avoid injury to the artery.

Morphometry and comparative histology of sinus and atrioventricular nodes in humans and pigs and their relevance in the prevention of nodal arrhythmias

The cardiac conduction system is a network structure that allows the initiation and fast propagation of electrical impulses that trigger the electrical depolarization of the myocardial tissue. The purpose of this work is to study the histological and morphometric characteristics of the different components of the sinus and atrioventricular nodes in humans and pigs and their relationship with supraventricular arrhythmias. In this study, we describe the morphometry of the sinus and atrioventricular nodes of 10 adult humans and 10 pig hearts. A computerized morphometric study has been carried out, where we determined the number of cells that compose the nodes as well as different parameters related to their shape and size. The sinus node in human and pig is a compact structure, whose shape is oblong. Their cells (nodal and transitional cells) are pale and located in the center and the periphery, respectively. The atrioventricular node has also a shape oblong. P cells are pale in both species, but in humans, they are smaller than cardiomyocytes. The T cells are small and pale in both species, identified by hematoxylin-eosin and desmin stains. We have observed through a morphometric profile that the structure of sinus and atrioventricular nodes of pigs and humans show few differences. Pigs can be used as models for hemodynamic applications and experimental studies that include atrial electrical conduction and, in this way, prevent the presentation of arrhythmias that can generate sudden deaths in humans and pigs.

Scarce Occurrence of Calcification in Human Sinoatrial Nodal Arteries in Old Age

To elucidate age-related changes of the sinoatrial (sinuatrial) nodal (SAN) artery, the authors investigated age-related changes of elements in the SAN artery by direct chemical analysis. In addition, the effects of different arterial origins, arterial sizes, and genders on element accumulation were investigated in the SAN artery. Fifty-nine formalin-fixed adult Thai hearts were dissected, and the following three types of the SAN artery were found: The first type was a single SAN artery arising from the right coronary artery (RCA). The second type was a single SAN artery arising from the proximal segment of the left circumflex artery (LCX). The third type was dual SAN artery arising from both the RCA and the LCX. For element analysis, both 41 single SAN arteries arising from the RCA and the LCX and 18 larger branches of dual SAN artery were used. After the arteries were incinerated with nitric acid and perchloric acid, element contents were determined by inductively coupled plasma-atomic emission spectrometry. It was found that seven element contents such as Ca, P, S, Mg, Zn, Fe, and Na did not change significantly in the SAN arteries with aging. Regarding the relationships among seven elements in the SAN arteries, extremely significant direct correlations were found among P, S, Mg, and Fe contents with one exception. However, no significant correlations were found between Ca and either P or Mg contents in the SAN arteries. To examine an effect of the different arterial origins on element accumulation, the SAN arteries were separated into the RCA and the LCX groups by the arterial origin and age-related changes of element contents were compared between two groups. It was found that there were no significant differences between the RCA and the LCX groups in age-related changes of Ca and P contents. No gender differences were found in age-related changes of Ca and P contents in the SAN arteries. To elucidate whether calcification occurred in the SAN arteries in old age, both the mass ratios of Ca/P and Mg/Ca were estimated in the SAN arteries. The mass ratio of Ca/P increased progressively in the SAN arteries with Ca increase, being not constant. The mass ratio of Mg/Ca decreased gradually in the SAN arteries with Ca increase, but the average mass ratio of Mg/Ca was very high, being 49.4 ± 16.5%. These results indicated that calcification scarcely occurred in the SAN arteries in old age, independently of the arterial origin and gender.

Anatomical Variations in the Sinoatrial Nodal Artery: A Meta-Analysis and Clinical Considerations

BACKGROUND AND OBJECTIVE

The sinoatrial nodal artery (SANa) is a highly variable vessel which supplies blood to the sinoatrial node (SAN). Due to its variability and susceptibility to iatrogenic injury, our study aimed to assess the anatomy of the SANa and determine the prevalence of its anatomical variations.

STUDY DESIGN

An extensive search of major electronic databases was performed to identify all articles reporting anatomical data on the SANa. No lower date limit or language restrictions were applied. Anatomical data regarding the artery were extracted and pooled into a meta-analysis.

RESULTS

Sixty-six studies (n = 21455 hearts) were included in the meta-analysis. The SANa usually arose as a single vessel with a pooled prevalence of 95.5% (95%CI:93.6-96.9). Duplication and triplication of the artery were also observed with pooled prevalence of 4.3% (95%CI:2.8-6.0) and 0.3% (95%CI:0-0.7), respectively. The most common origin of the SANa was from the right coronary artery (RCA), found in 68.0% (95%CI:55.6-68.9) of cases, followed by origin from the left circumflex artery, and origin from the left coronary artery with pooled prevalence of 22.1% (95%CI:15.0-26.2) and 2.7 (95%CI:0.7-5.2), respectively. A retrocaval course of the SANa was the most common course of the artery with a pooled prevalence of 47.1% (95%CI:36.0-55.5). The pooled prevalence of an S-shaped SANa was 7.6% (95%CI:2.9-14.1).

CONCLUSIONS

The SANa is most commonly reported as a single vessel, originating from the RCA, and taking a retrocaval course to reach the SAN. Knowledge of high risk anatomical variants of the SANa, such as an S-shaped artery, must be taken into account by surgeons to prevent iatrogenic injuries. Specifically, interventional or cardiosurgical procedures, such as the Cox maze procedure for atrial fibrillation, open heart surgeries through the right atrium or intraoperative cross-clamping or dissection procedures during mitral valve surgery using the septal approach can all potentiate the risk for injury in the setting of high-risk morphological variants of the SANa.

Anatomy of the sinoatrial nodal branch in Korean population: imaging with MDCT

Objective

To evaluate, on a retrospective basis, the anatomic characteristics of the arterial supply to the sinoatrial node (SAN) in the Korean population using an ECG-gated multi-detector CT (MDCT).

Materials and Methods

The electrocardiographic-gated MDCTs of 500 patients (258 men and 242 women; age range, 17-83 years; mean age, 58.6 ± 12.04 years) were analyzed retrospectively. In each case, the SAN artery (arteries) was named according to a special nomenclature with regard to origin, course, and termination.

Results

A total of 516 SAN arteries were visualized in 496 patients. The SAN was supplied by a single artery in 476 (96.4%) cases and by 2 arteries in 18 (3.6%) cases. The SAN originated from the right coronary artery in 265 (53.4%) cases and from the left circumflex in 213 (43%) cases.

Conclusion

This study can provide basic data on variations of the SAN artery in the Korean population.

Detection of pulmonary embolism by dual energy CT: correlation with perfusion scintigraphy and histopathological findings in rabbits

The purpose of the study was to compare the ability of dual energy CT (DECT) and perfusion scintigraphy (PS) to detect pulmonary embolism (PE) in a rabbit model. Gelfoam (n = 20) or saline (n = 4) was injected into the femoral vein of rabbits. After 2 h, DECT pulmonary angiography (CTPA) was used to create blood flow imaging (BFI) and fusion images. The rabbits then underwent PS. Pathological determination of locations and numbers of lung lobes with PE was recorded. The sensitivity and specificity for BFI, CTPA, fused images and PS were calculated using the pathological results as reference standards. Compared with pathological evaluation, CTPA correctly identified PE in 40 lobes and absence of emboli in 80 lobes, corresponding to a sensitivity and specificity of 100%. BFI and fused images correctly identified PE in 40 lobes and the absence of emboli in 78 lobes, corresponding to a sensitivity and specificity of 100% and 98%, respectively. PS correctly detected 27 lobes with PE and 65 lobes without PE, corresponding to a sensitivity and specificity of 68% and 81%, respectively. BFI, CTPA and fused images derived from a single contrast-enhanced DECT provide a higher diagnostic accuracy of detecting PE than PS in a rabbit model.

Incidence of anomalous origin of coronary artery in 1879 Chinese adults on dual-source CT angiography

Background and Objective. Dual-source CT (DSCT) has been used to detect coronary artery anomalies. The purpose of this study was to assess the incidence of anomalous origin of the coronary artery in Chinese adults. Methods. We summarised all patients who underwent DSCT coronary angiography (CTCA) from December 2006 to February 2008, and data of anomalous origin of the coronary artery in Chinese adults were recorded. Results. 1879 patients underwent CTCA during that period; 24 patients with an anomalous origin of the coronary artery were detected, giving an incidence of 1.3%. Fifteen patients had an anomalous origin of the right coronary artery (12 from left coronary sinus, 3 high takeoff), eight patients had an anomalous origin of the left coronary artery (LCA from posterior sinus of Valsalva in three cases, LCX from the right coronary sinus, LCX from RCA, high takeoff, LCA from right coronary sinus, and single coronary artery in one case, respectively), and one patient had an anomalous origin of both coronary arteries (high takeoff). Conclusion. The incidence of anomalous origin of the coronary artery in Chinese adults in this study is 1.3%. DSCT can clearly visualise the anomalous origin and course of the coronary artery and is a useful screening modality. (Neth Heart J 2010;18:466-70.).

Sinus node artery originating from the posterior part of the right coronary artery

PURPOSE

The purpose of the study was to examine the anatomical variations of the sinus node artery (SNA).

METHODS

Gross anatomical examination, angiographic evaluation and if necessary dissection were performed in 200 human hearts derived from victims of various accidents.

RESULTS

The SNA was a branch of the right coronary artery in 118 [59%] cases, the left circumflex in 78 [39%] cases and both coronary arteries in 4 [2%] cases. In one subject, the SNA was found to arise from the distal part of the right coronary artery.

CONCLUSIONS

In our case, the sinus node was perfused by a SNA arising from the mid-posterior segment of the right coronary artery. Knowledge of this anatomical variation is useful for anatomists and of clinical significance for the interventional cardiologists and mainly for the cardiac surgeons in planning the surgical procedures.

Dual-energy computed tomography in pulmonary embolism

The introduction of modern dual-energy CT (DECT) scanners has enabled contrast material to be distinguished at imaging without the need for a separate unenhanced scan. Images of pulmonary parenchymal contrast enhancement obtained using DECT improve the detection of defects, augmenting our ability to detect pulmonary emboli; however, with these advances new pitfalls are also introduced. In this pictorial review, we present the technique, clinical applications and causes and remedies of false results of dual-energy pulmonary parenchymal enhancement defects in pulmonary embolism.