Assessment of the coronary venous system using 256-slice computed tomography

Cardiac CT in CRT as a Singular Imaging Modality for Diagnosis and Patient-Tailored Management

Between 30-40% of patients with cardiac resynchronization therapy (CRT) do not show an improvement in left ventricular (LV) function. It is generally known that patient selection, LV lead implantation location, and device timing optimization are the three main factors that determine CRT response. Research has shown that image-guided CRT placement, which takes into account both anatomical and functional cardiac properties, positively affects the CRT response rate. In current clinical practice, a multimodality imaging approach comprised of echocardiography, cardiac magnetic resonance imaging, or nuclear medicine imaging is used to capture these features. However, with cardiac computed tomography (CT), one has an all-in-one acquisition method for both patient selection and the division of a patient-tailored, image-guided CRT placement strategy. This review discusses the applicability of CT in CRT patient identification, selection, and guided placement, offering insights into potential advancements in optimizing CRT outcomes.

Multi-modality imaging to guide the implantation of cardiac electronic devices in heart failure: is the sum greater than the individual components?

Heart failure is a clinical syndrome with an increasing prevalence and incidence worldwide that impacts patients' quality of life, morbidity, and mortality. Implantable cardioverter-defibrillator and cardiac resynchronization therapy are pillars of managing patients with HF and reduced left ventricular ejection fraction. Despite the advances in cardiac imaging, the assessment of patients needing cardiac implantable electronic devices relies essentially on the measure of left ventricular ejection fraction. However, multi-modality imaging can provide important information concerning the aetiology of heart failure, the extent and localization of myocardial scar, and the pathophysiological mechanisms of left ventricular conduction delay. This paper aims to highlight the main novelties and progress in the field of multi-modality imaging to identify patients who will benefit from cardiac resynchronization therapy and/or implantable cardioverter-defibrillator. We also want to underscore the boundaries that prevent the application of imaging-derived parameters to patients who will benefit from cardiac implantable electronic devices and orient the choice of the device. Finally, we aim at providing some reflections for future research in this field.

Study of coronary sinus anatomy during levophase of coronary angiography

BACKGROUND

Coronary sinus (CS) imaging has recently gained importance due to increasing need for mapping and ablation of electrophysiological arrhythmias and left ventricular (LV) pacing during cardiac resynchronization therapy (CRT). Retrograde venogram is the current standard for imaging CS and its tributaries.

AIM

To evaluate CS anatomy during levophase of routine coronary angiography to aid LV lead implantation during CRT.

METHODS

In this prospective observational study, 164 patients undergoing routine coronary angiography for various indications (Chronic stable angina-44.5%, acute coronary syndrome- 39.5%, Dilated cardiomyopathy-11%, atypical chest pain-5%) were included. Venous phase (levophase) of left coronary injection was recorded in left anterior oblique - cranial and right anterior oblique -cranial views. Visibility of coronary veins, width and shape of CS ostium, angulations of proximal CS with body of CS were noted. Presence, size, take-off angle and tortuosity of posterolateral vein (PLV), anterior interventricular veins (AIV) and middle cardiac vein (MCV) were also noted.

RESULTS

During levophase, visibility grade (Muhlenbruch grade) for coronary veins was 3 in 74% and 2 in 26% of cases. Visibility of CS did not correlate with body mass index. The diameter of CS ostium was < 10 mm, 10-15 mm and > 15 mm in 48%, 42% and 10% of patients respectively. Proximal CS was tubular in 136 (83%) patients and funnel-shaped in 28 (17%) patients. Sharp take-off angulation between ostium and body of CS was seen in 16 (10%) patients. Two or more PLV were present in 8 patients while PLV was absent in 52 (32%) patients. Angle of take-off of PLV with body of CS was favourable (0°-45°) in 65 (40%) patients. The angle was 45°-90° in 36 patients and difficult take-off angle (> 90°) was seen in 8 patients. Length of PLV reached distal third of myocardium in 84 cases and middle third in 11 cases. There was no tortuosity in 79 cases, a single bend in 29 cases and more than 2 bends in 4 cases. Thirty nine (24%) patients had other veins supplying posterior/Lateral wall of LV. There was a single vein supplying lateral/posterior wall in 31 (19%) patients. Diameter of MCV and AIV was significantly larger in patients with absent PLV as compared to patients with a PLV.

CONCLUSION

Levophase study of left coronary injection is effective in visualization of the CS in almost all patients undergoing coronary angiography and may be an effective alternative to retrograde venogram in patients with LV dysfunction or LBBB.

Mutual Arrangements of Coronary Blood Vessels within the Right Atrial Appendage Vestibule

Background: The aim of our study was to investigate the presence and mutual relationships of coronary vessels within the right atrial appendage (RAA) vestibule. Methods: We examined 200 autopsied hearts. The RAA vestibule was cross-sectioned along its isthmuses (superior, middle, and inferior). Results: The right coronary artery (RCA) was present in 100% of the superior RAA isthmuses but absent in 2.0% of hearts within the middle isthmus and in 6.5% of hearts within the inferior RAA isthmus. Its diameter was quite uniform along the superior (2.6 ± 0.8 mm), middle (2.9 ± 1.1 mm), and inferior (2.7 ± 0.9 mm) isthmuses (p = 0.12). The location of the RCA varied significantly, and it was sometimes accompanied by other accessory coronary vessels. In all the isthmuses, the RCA ran significantly closer to the endocardial surface than to the epicardial surface (p < 0.001). At the superior RAA isthmus, the artery was furthest from the right atrial endocardial surface and this distance gradually decreased between the middle RAA isthmus and the inferior RAA. Conclusions: This study was the most complex analysis of the mutual arrangements and morphometric characteristics of coronary blood vessels within the RAA vestibule. Awareness of additional blood vessels within the vestibule can help clinicians plan and perform safe and efficacious procedures in this region.

Morphometric Characterization of Human Coronary Veins and Subvenous Epicardial Adipose Tissue-Implications for Cardiac Resynchronization Therapy Leads

Subvenous epicardial fat tissue (SEAT), which acts as an electrical insulation, and the venous diameter (VD) both constitute histomorphological challenges for optimal application and lead design in cardiac synchronization therapy (CRT). In this study, we characterized the morphology of human coronary veins to improve the technical design of future CRT systems and to optimize the application of CRT leads. We retrospectively analyzed data from cardiac computed tomography (CT) of 53 patients and did studies of 14 human hearts using the postmortem freeze section technique and micro CT. Morphometric parameters (tributary distances, offspring angles, luminal VD, and SEAT thickness) were assessed. The left posterior ventricular vein (VVSP) had a mean proximal VD of 4.0 ± 1.4 mm, the left marginal vein (VMS) of 3.2 ± 1.5 mm and the anterior interventricular vein (VIA) of 3.9 ± 1.3 mm. More distally (5 cm), VDs decreased to 2.4 ± 0.6 mm, 2.3 ± 0.7 mm, and 2.4 ± 0.6 mm, respectively. In their proximal portions (15 mm), veins possessed mean SEAT thicknesses of 3.2 ± 2.4 (VVSP), 3.4 ± 2.4 mm (VMS), and 4.2 ± 2.8 mm (VIA), respectively. More distally (20-70 mm), mean SEAT thicknesses decreased to alternating low levels of 1.3 ± 1.1 mm (VVSP), 1.7 ± 1.1 mm (VMS), and 4.3 ± 2.6 mm (VIA), respectively. In contrast to the VD, SEAT thicknesses alternated along the further distal vein course and did not display a continuous decrease. Besides the CRT responsiveness of different areas of the LV myocardium, SEAT is a relevant electrophysiological factor in CRT, potentially interfering with sensing and pacing. A sufficient VD is crucial for successful CRT lead placement. Measurements revealed a trend toward greater SEAT thickness for the VIA compared to VVSP and VMS, suggesting a superior signal-to-noise-ratio in VVSP and VMS.

Temporal changes of the diameter of the coronary sinus during the cardiac cycle

INTRODUCTION

Currently, there are no studies that analyse the changes in the cardiac venous system that are dependent on the phase (RR interval) of reconstruction. The aim of the study was to assess the size of the coronary sinus at two measurement sites depending on the phase of the heart cycle.

METHODS

Fifty patients were included. Cardiac computed tomography was performed in all of the patients due to a suspicion of coronary artery disease (typical indications) using a dual-source Siemens Somatom Force scanner. The "MM reading" presets were used to measure the coronary sinus ostium (measurement 1) and the coronary sinus trunk, which is close to the great cardiac vein (measurement 2) in millimetres. All of the calculations were performed on axial scans using 0%-100% and a 256 × 256 matrix.

RESULTS

The largest CS was found at the 30%, 40% and 50% RR interval-this phenomenon occurred in 37 of the 50 cases (74%). The CS was largest in the 30% phase (9/50 cases; 18%), in the 40% phase (17/50 cases; 34%) and in the 50% phase, and it was the largest in 11 of the 50 cases (22%). There were also no gender-related differences.

CONCLUSIONS

The size of the coronary sinus varies with the phase of the heart cycle. At the 40% phase, it is largest in most cases.

Characterization of non-response to cardiac resynchronization therapy by post-procedural computed tomography

INTRODUCTION

Causes of non-response to cardiac resynchronization therapy (CRT) include mechanical dyssynchrony, myocardial scar, and suboptimal left ventricular (LV) lead location. We aimed to assess the utility of Late Iodine Enhancement Computed Tomography (LIE-CT) with image subtraction in characterizing CRT non-response.

METHODS

CRT response was defined as a decrease in LV end-systolic volume > 15% at 6 months. LIE-CT was performed after 6 months, and analyzed global and segmental dyssynchrony, myocardial scar, coronary venous anatomy, and position of LV lead relative to scar and segment of latest mechanical contraction.

RESULTS

We evaluated 29 patients (age 71 ± 12 years; 72% men) including 18 (62%) responders. All metrics evaluating residual dyssynchrony such as wall motion index and wall thickness index were worse in non-responders. There was no difference in presence and extent of scar between responders and non-responders. However, in non-responders, the LV lead was more often over an akinetic/dyskinetic area (72% vs. 22%, p = .007), a fibrotic area (64% vs. 8%, p = .0007), an area with myocardial thickness < 6 mm (82% vs. 22%, p = .002), and less often concordant with the region of maximal wall thickness (9% vs. 72%, p = .001). Among the 11 non-responders, eight had at least another coronary venous branch visualized by CT, including three (27%) coursing over a potentially interesting myocardial area (free of scar, with normal wall motion, and with a myocardial thickness ≥6 mm).

CONCLUSION

LIE-CT with image subtraction allows a comprehensive characterization of patients after CRT and may provide clues for management of non-responders.

Evaluation of the anatomical variations of the coronary venous system in patients with coronary artery calcification using 256-slice computed tomography

The factors that determine the anatomical variations of the coronary venous system (CVS) are poorly understood. The objective of this study was to evaluate the anatomical variations of the CVS in patients with coronary artery calcification. 196 patients underwent non-contrast CT and coronary CT angiography using 256-slice CT. All subjects were divided into four groups based on their coronary artery calcium score (CACS): 50 patients with CACS = 0 Agatston unit (AU), 52 patients with CACS = 1–100 AU, 44 patients with CACS = 101–400 AU, and 50 patients with CACS > 400 AU. The presence of the following cardiac veins was evaluated: the coronary sinus (CS), great cardiac vein (GCV), posterior interventricular vein (PIV), posterior vein of the left ventricle (PVLV), left marginal vein (LMV), anterior interventricular vein (AIV), and small cardiac vein (SCV). Vessel diameters were also measured. We found that the CS, GCV, PIV, and AIV were visualized in all patients, whereas the PVLV and LMV were identified in a certain proportion of patients: 98% and 96% in the CACS = 0 AU group, 100% and 78.8% in the CACS = 1–100 AU group, 93.2% and 77.3% in the CACS = 101–400 AU group, and 98% and 78% in the CACS > 400 AU group, respectively. The LMV was less often identified in the last three groups than in the first group (p < 0.05). The frequency of having either one PVLV or LMV was higher in the last three groups than in the first group (p < 0.05). No significant differences in vessel diameters were observed between the groups. It was concluded that patients with coronary artery calcification were less likely to have the LMV, which might hamper the left ventricular lead implantation in cardiac resynchronization therapy.

Optimal site selection and image fusion guidance technology to facilitate cardiac resynchronization therapy

INTRODUCTION

Cardiac resynchronization therapy (CRT) has emerged as one of the few effective treatments for heart failure. However, up to 50% of patients derive no benefit. Suboptimal left ventricle (LV) lead position is a potential cause of poor outcomes while targeted lead deployment has been associated with enhanced response rates. Image-fusion guidance systems represent a novel approach to CRT delivery, allowing physicians to both accurately track and target a specific location during LV lead deployment.

AREAS COVERED

This review will provide a comprehensive evaluation of how to define the optimal pacing site. We will evaluate the evidence for delivering targeted LV stimulation at sites displaying favorable viability or advantageous mechanical or electrical properties. Finally, we will evaluate several emerging image-fusion guidance systems which aim to facilitate optimal site selection during CRT.

EXPERT COMMENTARY

Targeted LV lead deployment is associated with reductions in morbidity and mortality. Assessment of tissue characterization and electrical latency are critical and can be achieved in a number of ways. Ultimately, the constraints of coronary sinus anatomy have forced the exploration of novel means of delivering CRT including endocardial pacing which hold promise for the future of CRT delivery.

Comparisons of the accuracy of radiation diagnostic modalities in brain tumor: A nonrandomized, nonexperimental, cross-sectional trial

Tumor morphology improved sensitivity, accuracy, and specificity of the diagnosis, but all diagnostic techniques have attenuation correction issues.To compare computed tomographic (CT), positron emission tomographic (PET), and magnetic resonance imaging (MRI) characteristics of patients with brain tumor in a Chinese setting.A nonrandomized, nonexperimental, cross-sectional trial.Jining No. 1 People's Hospital, China.In total, 127 patients who had clinically confirmed a brain tumor were included in the cross-sectional study. Patients were subjected to brain CT, MRI, and PET. The tumors resected after brain surgery were subjected to morphological diagnosis. Statistical analysis of data of surgically removed tumor and that of different methods of diagnosis was performed using Wilcoxon test following Tukey-Kramer test. Spearmen correlation was performed between diagnostic modalities and in vivo morphology. Results were considered significant at 99% of confidence level.The data of diameter and volume of tumor derived from CT (Spearman r = 0.9845 and 0.9706), and MRI (Spearman r = 0.955 and 0.2378) were failed to correlate with that of that of the surgically removed tumor. However, prediction of diameter and volume of the tumor by PET (Spearman r = 0.9922 and 0.9921) were correlated with that of the surgically removed tumor. CT and MRI were failed to quantified pituitary adenomas.The study was recommended PET for assessment of brain tumor.

Association of Difference in Coronary Sinus Diameter by Computed Tomographic Angiography Between Patients in and Not in Stable Atherosclerotic Plaque(S)

Background

Pathological finding fail to describe the morphology of coronary arterial plaques. Retrograde cardiac arteriography is a complicated procedure and does not detect all left posterior and marginal veins of the heart. Magnetic resonance angiography has long scan time and low spatial resolution. The objective of the present study was to assess the possible utility of the difference in coronary sinus diameter to quantify stable atherosclerotic plaque(s) using 256-slice coronary computed tomographic angiography.

Material/Methods

A total of 336 patients were divided into 2 groups with 168 patients each. Patients who had heart failure were included in the study group and those who did not were included in the non-study group. Patients were subjected to cross-sectional study. Cardiovascular images were performed with 256-slice coronary computed tomographic angiography with a prospective electrocardiogram and clinical manifestation. Two-tailed paired t test following Dunnett’s multiple comparison tests was performed for the quantitative measurement of coronary computed tomographic angiography and clinical manifestation at 99% confidence level.

Results

The clinical manifestation did not clearly show cardiac abnormality. The diameters of the superoinferior coronary sinus ostium was than that of the anteroposterior coronary sinus ostium, (p<0.0001, q=26.325). There was the difference in size of the coronary sinus ostium between patients in and not in heart failure (p<0.0001). The study group patients had longer coronary sinuses than patients in the non-study group (p<0.0001).

Conclusions

256-slice computed tomographic angiography is a feasible and is non-invasive bio-tool for evaluation of coronary artery anatomy.

Comprehensive use of cardiac computed tomography to guide left ventricular lead placement in cardiac resynchronization therapy

Background

Optimal lead positioning is an important determinant of cardiac resynchronization therapy (CRT) response.

Objective

The purpose of this study was to evaluate cardiac computed tomography (CT) selection of the optimal epicardial vein for left ventricular (LV) lead placement by targeting regions of late mechanical activation and avoiding myocardial scar.

Methods

Eighteen patients undergoing CRT upgrade with existing pacing systems underwent preimplant electrocardiogram-gated cardiac CT to assess wall thickness, hypoperfusion, late mechanical activation, and regions of myocardial scar by the derivation of the stretch quantifier for endocardial engraved zones (SQUEEZ) algorithm. Cardiac venous anatomy was mapped to individualized American Heart Association (AHA) bull’s-eye plots to identify the optimal venous target and compared with acute hemodynamic response (AHR) in each coronary venous target using an LV pressure wire.

Results

Fifteen data sets were evaluable. CT-SQUEEZ–derived targets produced a similar mean AHR compared with the best achievable AHR (20.4% ± 13.7% vs 24.9% ± 11.1%; P = .36). SQUEEZ-derived guidance produced a positive AHR in 92% of target segments, and pacing in a CT-SQUEEZ target vein produced a greater clinical response rate vs nontarget segments (90% vs 60%).

Conclusion

Preprocedural CT-SQUEEZ–derived target selection may be a valuable tool to predict the optimal venous site for LV lead placement in patients undergoing CRT upgrade.

Computed Tomography in Congenital Heart Disease: Clinical Applications and Technical Considerations

Computed tomography (CT) is increasingly applied as an aid to clinical decision making in congenital heart disease (CHD) with regard to surgery, interventional catheterizations, and follow-up. It is particularly useful for the assessment of vascular and airway abnormalities. Updated knowledge of CT imaging techniques is mandatory not only for the optimization of image acquisition protocols, but also for the postprocessing reconstruction and interpretation of CT findings. The purpose of this article was to review the clinical indications, techniques, and dose reduction methods for CT imaging in children and adults with CHD. Relevant discussion and illustrations of common forms of CHD evaluated by CT are presented.

The Thebesian valve height/coronary sinus ostium diameter ratio (H/D-Ratio) as a new indicator for specifying the morphological shape of the valve itself in multisliced computed tomography

BACKGROUND

The coronary sinus ostium (CSO) is covered by the Thebesian valve (ThebV), which has a variable shape when assessed subjectively. The ThebV is an anatomical barrier during CS cannulation, which may be complicated due to the valves' size. The types of valves are: cord, remnant, semilunar, fold, and mesh/fenestrated. The ThebV can be visible using multisliced computed tomography (MSCT), however, this method cannot show the ThebV's morphological shape, only its size.

METHODS

301 randomly selected autopsied human hearts were examined. The shape of the valve was subjectively assessed, whereas the ThebV height (H) and the CSO diameter (D) were measured. The H/D-Ratio was computed as the ThebV height divided by the CSO diameter, afterwards k-means cluster analysis was performed to estimate H/D-Ratio's range of values between valves. MSCT scans from 114 patients that underwent CSO cannulation were objectively evaluated based on similar measured parameters in accordance with received H/D-Ratio values.

RESULTS

Boundaries of ratio evaluations between remnant and semilunar, and semilunar and fold types were 0.35 and 0.65 respectively. In MSCT scans, the ThebV was recorded in 61 cases (remnant=5.3%, semilunar=24.6%, fold=16.7%, cord=0.0%, mesh/fenestrated=7.9%). Except for the remnant and cord types, the other types appear similarly as in the cadaveric and MSCT studies. There were no differences between ThebV height and the CSO diameter in cadavers and MSCT studies.

CONCLUSION

The H/D-Ratio can be useful in assessing ThebV shape as visualized in MSCT. We give threshold values for the H/D-Ratio which easily allow the ThebV shape to be determined.