Reduction of metallic artifacts from the novel leadless pacemaker using single-energy metal artifact reduction algorithm in coronary CT angiography

Abstract

Objective

To evaluate the efficacy of single-energy metal artifact reduction (SEMAR) algorithm in removing metallic artifacts for patients with novel leadless pacemakers (PMs) compared to those with conventional transvenous PMs.

Methods

30 patients with transvenous PMs and 30 patients with leadless PMs having coronary CT angiography (CCTA) were included. Images were reconstructed using two methods: a conventional hybrid-iterative reconstruction (HIR) algorithm separately, and the HIR combined with SEMAR algorithm. The artifact index (AI) was calculated for both datasets to quantitatively assess the artifact reduction. Two senior radiologists independently scored the artifact extent and diagnostic confidence of surrounding tissues. The position of artifacts-impaired tissues was also visually evaluated as follows: non-impaired, impaired, and equivocal. The study was ethics committee-approved.

Results

The leadless PM_SEMAR exhibited significantly lower AIs than the leadless PM_non−SEMAR, with an improvement of hypodense artifacts and a significant reduction of hyperdense artifacts (all p < 0.001). The AIs of leadless PMs performed with and without SEMAR were slightly lower than those of transvenous PMs, although no statistical difference existed (all p > 0.05). Qualitatively, the artifact extent of SEMAR significantly outperformed non-SEMAR in both types of PM (p < 0.001). The aorta, right coronary artery, right atrium, and left ventricle were less impaired in leadless PM_non−SEMAR compared to transvenous PM_non−SEMAR (all p < 0.05).

Conclusions

SEMAR provides effective reduction of metallic artifacts from both types of cardiac PMs. The artifact-impaired tissues are fewer on leadless PMs, resulting in an enhanced diagnostic confidence in the surrounding tissues.

Introduction

Transvenous pacemaker (PM) retain efficacy in managing severe arrhythmias and heart failure, however, their implantation carries significant risks. Approximately 12% of recipients experience complications, including cardiac perforation, lead dislodgement, infection [1, 2], which worsen clinical outcomes and increase healthcare burdens [3]. The Micra VR, a first-generation leadless single-chamber PM approved by the FDA in 2016 [4], features a compact design that enables complete implantation within the right ventricular septum. This approach may mitigate conventional complications associated with subcutaneous pockets and transvenous leads.

Although chest radiography is the first-line modality for evaluating transvenous lead positioning and integrity [5], high-resolution multidetector computed tomography (MDCT) proves indispensable for detecting deviced-related cardiac and extracardiac complications [6, 7]. Nevertheless, metallic components preferentially absorb low-energy photons with lesser attenuation of high-energy photons, generating beam-hardening and photon-starvation artifacts [8, 9]. The distortions degrade image quality in diagnosing cardiac perforation, pericardial effusion, thrombosis and myocardial injury [10–12]. Desipte spectral CT has provided certain solutions for artifacts removal, it requires specialized hardware and is prone to motion-misregistration artifacts, which hampers its application in routine practice [13, 14].

The single-energy metal artifact reduction (SEMAR) algorithm has been proven its capacity of removing metallic artifacts in cardiac implantable electric devices, hip prosthesis, and post-treatment intracranial aneurysms [10, 15, 16]. To our knowledge, SEMAR has not yet been evaluated in patients with leadless PMs. Therefore, the purpose of our study was to investigate the performance of SEMAR algorithm for the reduction of metallic artifacts in CCTA examinations following leadless PM implantation. We also explored whether SEMAR could mitigate the artifacts-impaired tissue surrounding leadless PMs compared with transvenous PMs.

Materials and methods

Patient selection

Between March and August 2023, patients who underwent coronary CT angiography (CCTA) examinations for suspected coronary artery disease were prospectively included. The following inclusion criteria were: (1) age above 18 years; (2) after cardiac PM implantation; (3) complete clinical information. The exclusion criteria were the following: (1) history of iodine allergy; (2) presence of serious and potentially confounding diseases, such as severe asthma, hepatic and renal insufficiency. This study was a retrospective subgroup analysis of the prospective CCTA cohort at our institution and was approved by our institutional ethics committee (No. 220120-02). From this cohort, we then identified and analyzed patients with pre-existing permanent pacemaker implantation, and all written informed consent were obtained.

CT image acquisition

Patients were scanned on a 320-row detector CT scanner (Aquilion ONE Genesis, Canon Medical Systems, Otawara, Japan). The scanning parameters were as follows: tube voltage, 120 kV; automatic tube current (^SUREExposure 3D); gantry rotation time, 0.275s. All patients were administered sublingual nitroglycerin 5 min prior to the scanning and did not receive beta-blockers. Bolus tracking was applied with a trigger threshold of 280 HU in the descending aorta. Non-ionic contrast material (Iohexol Injection, 370 mg/mL, Yangtze River Pharmaceutical Group Co. Ltd, China) was injected at a flow rate of 3.5-5.0 mL/s into the antecubital vein, followed by a 30 ml of saline at the same flow rate. Images reconstructed with hybrid-iterative reconstruction (HIR) alone were defined as the non-SEMAR group. A second reconstruction was performed with the addition of SEMAR algorithm (SEMAR group).

Quantitative evaluation

All CT images were transferred to a dedicated workstation (Vitrea, Canon Medical Systems, Otawara, Japan) for further measurement. In non-SEMAR images, cross-sectional levels exhibiting the largest artifacts around the PMs were identified. Two regions of interest (ROIs) were then placed in a hypodense region and a hyperdense region, respectively, each with an area of approximately 50 mm² (Fig. 1). An additional ROI (approximately 100 mm²) was positioned at the section that contains metallic artifacts-free, serving as the reference tissue. The CT attenuation and standard deviation (SD) within each ROI was recorded. The SD of reference tissue was defined as the background image noise.

Fig. 1.

Schematic diagram of ROI positions. Leadless PM without (a) and with SEMAR (b), and transvenous PM without (c) and with SEMAR (d)

We calculated the artifact index (AI) in accordance with the previous literatures [10], specifically: . The corrected attenuation for hypodense and hyperdense artifacts was determined by the difference in attenuation between the artifacts-impaired tissues and the reference tissue, on the basis that both classes of artifacts had occurred in artifact-surrounded areas. Accordingly, this measurement was applied in order to quantify the pure artifact content as much as possible [17].

Qualitative evaluation

Two senior radiologists (with 20- and 23-year experience in cardiac imaging) independently reviewed the CT images, fully blinded to the acquisition methods. A 5-point Likert scale was used to evaluate the artifact extent and diagnostic confidence of surrounding the PMs. In cases of discrepancy, the final interpretation was resolved by consensus.

The subjective assessment of hypo- and hyperdense artifacts surrounding leadless PMs and transvenous PMs leads extent was interpreted as follows: 1 = massive artifacts; 2 = pronounced artifacts; 3 = moderate artifacts; 4 = minor artifacts; 5 = no or almost no artifacts. The diagnostic confidence was scored as: 1 = no confidence; 2 = restricted confidence; 3 = hampered confidence; 4 = confidence; 5 = full confidence. In addition, diagnostic confidence of the heart and major associated vessels adjacent to leadless PMs and transvenous PMs leads regarding heart chambers, myocardium, and pericardium, also considering potential cardiac pathologies, e.g., thrombosis, calcification, myocardial hypertrophy, and pericardial effusion: 1 = Insufficient diagnostic quality/certainty; 2 = Restricted diagnostic quality/certainty by strong artifacts; 3 = Hampered diagnostic quality/certainty by moderate artifacts; 4 = Marginally affected diagnostic quality/certainty by minor streaks; 5 = Full diagnostic quality/certainty without artifacts/almost no artifacts [18].

The radiologists also whether evaluated cardiac structures and peripheral tissues was impaired by the artifacts from cardiac PMs, which included aorta, left anterior descending (LAD) artery, left circumflex (LCX) artery, right coronary artery (RCA), right ventricle (RV), right atrium (RA), left ventricle (LV), epicardial adipose tissue (EAT), and pericoronary adipose tissue (PCAT). A 3-point scale was used, which reflected the following outcomes: 1 = impaired and undiagnosable; 2 = possibly impaired but uncertain with suspicious quality; 3 = slight or no impairment with definite diagnostic confidence [10].

Statistical analysis

Statistical analysis was performed using SPSS software (Version 22.0; IBM, New York, USA). The Kolmogorov-Smirnov test was applied to ascertain the normality of distribution for continuous variables. Quantitative results were expressed as mean ± SD, and qualitative results were expressed as number of cases and corresponding percentages. The Wilcoxon signed-rank test and the Mann-Whitney U Test were used to analyze the intra- and intergroup differences, respectively. Statistical significance was defined as p-value < 0.05. The Cohen’s kappa value was calculated to determine the inter-observer agreement, and categorized as follows: 0.81-1.00, excellent; 0.61–0.80, good; 0.41–0.60, moderate; 0.21–0.40, fair; and 0.00-0.20, poor [19]. The intraclass correlation coefficient (ICC) was used to assess the inter-observer consistency between two observers in evaluating artifact-impaired tissues, with ICC < 0.20 indicating poor consistency, 0.21 ≤ ICC < 0.80 indicating fair consistency, and ICC ≥ 0.81 indicating good consistency [20].

Results

Patient baseline characteristics

A total of 60 patients were included in this study. There was no statistical difference in baseline characteristics between patients with leadless and transvenous PMs, e.g., age, gender, heart rate, and BMI (kg/m²). Detailed information is presented in Table 1.

Table 1.

Patient characteristics

	Transvenous PM (n=30)	Leadless PM (n=30)	P
Age (years)	66.37 ± 10.95	68.50 ± 13.68	0.27
Male	16 (53.3)	19 (63.3)	0.60
BMI (kg/m2)	24.53 ± 3.83	24.33 ± 3.45	0.97
Heart rate (bpm)	71.03 ± 17.99	69.37 ± 12.83	0.96
Hypertension	14 (46.7)	11 (36.7)	0.60
Diabetes mellitus	3 (10.0)	8 (26.7)	0.18
Smoking	7 (23.3)	10 (33.3)	0.57
Alcoholic drink	7 (23.3)	10 (33.3)	0.57
History of CAD	13 (43.3)	11 (36.7)	0.79
Indications of pacemaker			0.73
Sick sinus syndrome	10 (33.3)	11 (36.7)
Atrioventricular block	9 (30.0)	11 (36.7)
Atrial fibrillation	11 (36.7)	8 (26.7)

Data expressed as mean ± standard deviation or counts (percentage). PM, pacemaker; BMI, body mass index; CAD, coronary artery disease

Quantitative assessment

Intragroup comparisons (SEMAR vs. non-SEMAR group)

Results of the quantitative assessment are shown in Table 2. The mean AIs of leadless PM_SEMAR were significantly lower than leadless PM_non−SEMAR (59.28 ± 15.35 HU vs. 243.82 ± 79.26 HU, p < 0.001). Compared to leadless PM_non−SEMAR, the corrected attenuation of leadless PM_SEMAR showed a significant increase for hypodense artifacts (-314.67 ± 100.31 HU vs. -35.47 ± 58.90 HU, p < 0.001) and a significant decrease for hyperdense artifacts (218.39 ± 131.25 vs. -3.36 ± 50.15 HU, p < 0.001), respectively.

Table 2.

The results of objective analysis of metallic artifacts

	Corrected attenuation (HU)						Artifacts index (HU)
	Hypodense artifacts			Hyperdense artifacts			SEMAR	Non-SEMAR	P*
	SEMAR	Non-SEMAR	P*	SEMAR	Non-SEMAR	P*
Leadless PM	-35.47 ± 58.90	-314.67 ± 100.31	<0.001	-3.36 ± 50.15	218.39 ± 131.25	<0.001	59.28 ± 15.35	243.82 ± 79.26	<0.001
Transvenous PM	3.80 ± 51.30	-320.70 ± 165.95	<0.001	47.39 ± 75.56	345.60 ± 241.31	<0.001	62.61 ± 38.04	258.72 ± 89.92	<0.001
P †	0.08	0.43	/	<0.05	<0.05	/	0.56	0.43	/

Data are presented as mean ± standard deviation

^*P values of intragroup comparisons

^†P values of intergroup comparisons

PM, pacemaker; SEMAR, single-energy metal artifact reduction

Intergroup comparisons (leadless vs. transvenous PMs)

The mean AIs of the leadless PMs was lower than the transvenous PMs, although no significant differences were found in either the non-SEMAR (243.82 ± 79.26 vs. 258.72 ± 89.92 HU, p > 0.05) or SEMAR groups (59.28 ± 15.35 vs. 62.61 ± 38.04 HU, p > 0.05). The corrected attenuation within hypodense artifacts were comparable between leadless and transvenous PMs in both the non-SEMAR (-314.67 ± 100.31 vs. -320.70 ± 165.95 HU, p > 0.05) and SEMAR groups (-35.47 ± 58.90 vs. 3.80 ± 51.30 HU, p > 0.05). Compared with transvenous PMs, the corrected attenuation within hyperdense artifacts yielded a significant decrease in leadless PM_non−SEMAR (218.39 ± 131.25 vs. 345.60 ± 241.31 HU, p < 0.05) and leadless PM_SEMAR (-3.36 ± 50.15 vs. 47.39 ± 75.56 HU, p < 0.05).

Qualitative assessment

Intragroup comparisons (SEMAR vs. non-SEMAR group)

Compared to the leadless PM_non−SEMAR, the leadless PM_SEMAR obtained higher scores for artifact extent (4.35 ± 0.54 vs. 1.78 ± 0.69, p < 0.001). The diagnostic confidence exhibited a significantly increase in the leadless PM_SEMAR compared to the leadless PM_non−SEMAR (4.62 ± 0.52 vs. 2.20 ± 0.65, p < 0.001). Detailed results of the qualitative assessment are provided in Table 3, and Fig. 2 shows the example case.

Table 3.

The results of subjective analysis of metal artifacts

	Artifact extent			Diagnostic confidence
	SEMAR	Non-SEMAR	P *	SEMAR	Non-SEMAR	P *
Leadless PM	4.35 ± 0.54	1.78 ± 0.69	<0.001	4.62 ± 0.52	2.20 ± 0.65	<0.001
Transvenous PM	3.87 ± 0.69	1.75 ± 0.57	<0.001	4.05 ± 0.80	1.92 ± 0.74	<0.001
P †	<0.05	0.88	/	<0.05	0.11	/

Data are presented as mean ± standard deviation

^*P values of intragroup comparisons

^†P values of intergroup comparisons

PM, pacemaker; SEMAR, single-energy metal artifact reduction

Fig. 2.

Multiplanar reconstruction images of a patient with leadless PM. Compared to non-SEMAR (1a), SEMAR (1b) exhibited effective reduction of artifacts from leadless PM. SEMAR clearly displayed the boundary between the PM and the myocardium and pericardial adipose tissue (1d), whereas non-SEMAR (1c) revealed a significant impairment between the tissues and PM

Intergroup comparisons (leadless vs. transvenous PMs)

There was no significant difference for the artifact extent and diagnostic confidence in both leadless PM_non−SEMAR and transvenous PM_non−SEMAR (all p > 0.05). The artifact extent was higher in leadless PM_SEMAR than that in transvenous PM_SEMAR (4.35 ± 0.54 vs. 3.87 ± 0.69, p < 0.05). Similarly, the diagnostic confidence for leadless PM_SEMAR was higher compared to transvenous PM_SEMAR (4.62 ± 0.52 vs. 4.05 ± 0.80, p < 0.05). The inter-observer agreement was excellent for the artifact extent and diagnostic confidence (Kappa value of 0.88 and 0.95, respectively).

Evaluation of artifacts-impaired area

Intragroup comparisons (SEMAR vs. non-SEMAR group)

SEMAR substantially improved the visualization of artifacts-impaired areas in the LAD, RA, RV, LV, EAT, and PCAT in patients with leadless PMs (all p < 0.001). An image example is given in Fig. 2, demonstrating that artifacts-impaired areas were significantly reduced in the leadless PM_SEMAR compared to leadless PM_non−SEMAR. Notably, leadless PM_SEMAR reclassified 25 initially diagnosed as impaired and 5 as equivocal in the LAD to 27 unimpaired and 3 equivocal in the leadless PM_non−SEMAR (p < 0.001). Artifacts minimally influenced the LCX and aorta, with negligible impact on the RCA. Detailed results of artifacts-impaired tissues are presented in Table 4.

Table 4.

Subjective evaluation of metal artifacts-affected areas

	Aorta	LCX	LAD	RCA	RA	RV	LV	EAT	PCAT
Transvenous PMNon-SEMAR	3/6/21	0/0/30	23/1/6	20/4/6	29/1/0	30/0/0	29/0/1	26/2/2	22/3/5
Transvenous PMSEMAR	0/3/27	0/0/30	0/2/28	0/6/24	1/14/15	1/13/16	1/9/20	0/7/23	0/6/24
Leadless PMNon-SEMAR	0/1/29	0/0/30	25/5/0	0/5/25	0/18/12	27/3/0	24/6/0	28/2/0	23/7/0
Leadless PMSEMAR	0/0/30	0/0/30	0/3/27	0/0/30	0/0/30	0/13/17	0/6/24	0/12/18	0/4/26
P *
Transvenous PMNon-SEMAR vs. Transvenous PMSEMAR	0.09	1	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001
Leadless PMNon-SEMAR vs. Leadless PMSEMAR	1	1	<0.001	0.05	<0.001	<0.001	<0.001	<0.001	<0.001
P †
Transvenous PMNon-SEMAR vs. Leadless PMNon-SEMAR	0.02	1	0.01	<0.001	<0.001	0.24	0.02	0.55	0.04
Transvenous PMSEMAR vs. Leadless PMSEMAR	0.24	1	1	0.02	<0.001	1	0.38	0.27	0.73

Data are presented as numbers of patients (Impaired/Equivocal/Unimpaired)

^*P values of intragroup comparisons

^†P values of intergroup comparisons

PM, pacemaker; SEMAR, single-energy metal artifact reduction; LCX, left circumflex artery; LAD, left anterior descending artery; RCA, right coronary artery; RA, right atrium; RV, right ventricle; LV, left ventricle, EAT, epicardial adipose tissue; PCAT, pericoronary adipose tissue

Intergroup comparisons (leadless vs. transvenous PMs)

Figure 3 shows stacked bar plots of scores for artifacts-impaired tissues. Over 80% of the scores for RCA were rated 3 in leadless PM_non−SEMAR, while these proportion was only 20% in transvenous PM_non−SEMAR. The artifacts-impaired areas, such as aorta, RCA, RA, and LV were fewer for leadless PM_non−SEMAR compared to transvenous PM_non−SEMAR (all p < 0.05). Additionally, the impaired areas of LAD and PCAT were broader for leadless PM_non−SEMAR than for transvenous PM_non−SEMAR (all p < 0.05). The areas of the RCA and RA on leadless PM_SEMAR were less impaired than those on transvenous PM_SEMAR (all p < 0.05). Two representative cases are shown in Figs. 2 and 4.

Fig. 3.

Stacked bar plot shows the scores of artifacts-impaired tissues across transvenous PMs and leadless PMs. Each bar indicates the proportion of score attributed by the radiologists for a tissue. The 3-point scale was as follows: 3, unimpaired (green); 2, equivocal (brown); 1, impaired (red)

Fig. 4.

Multiplanar reconstruction images of a patient with transvenous PM. Non-SEMAR (2a) exhibited extensive metal artifacts, while SEMAR (2b) effectively reduced artifacts from the PM. A lead perforation was observed in non-SEMAR (2c) which did not occur in SEMAR (2d)

Discussion

In this study, we comprehensively evaluated the performance and clinical utility of SEMAR for the reduction of metallic artifacts from leadless PMs. Our major findings indicate that fewer areas were impaired by artifacts in leadless PMs than in transvenous PMs, and both subjective and objective results showed that SEMAR efficiently reduces the metallic artifacts, thereby potentially improving the diagnostic quality of assessing complications associated with both types of cardiac PMs.

The number of post-implantation patients with cardiac PMs is increasing in clinical practice. Imaging examinations to determine the location of implanted electrodes and to diagnose suspected coronary artery disease are essential. High-resolution CT is considered the non-invasive gold standard for evaluating lead perforation in cardiac implantable devices (CIEDs). However, metallic artifacts caused by implantation adversely affect image quality, making definitive diagnosis challenging. Previous study concluded that SEMAR reduced the metallic artifacts in metal coils, hip, knee, and dental prostheses in CT [15, 21]. More recent research has focused on metallic artifacts caused by the device leads and improved the image quality of tissues adjacent to CIEDs. SEMAR had demonstrated efficient artifact reduction and enhanced the diagnostic value of the CIED lead perforation in CCTA examinations [10], which is consistent with the results of our study (Fig. 4). DECT effectively reduces metal artifacts, particularly around large implants, by reconstructing higher keV virtual monoenergetic images, but it often increases image noise and relies on vendor‑specific acquisition protocols [22]. Unlike dual‑energy CT, which acquires two distinct energy spectra and generates virtual monoenergetic images to mitigate beam‑hardening artifacts, SEMAR operates on standard single‑energy raw data without specialized hardware [23].

Prior research has predominantly explored short-term complications associated with PMs, specifically contrasting leadless- with transvenous PMs. These studies have concluded the superior feasibility and safety of leadless PMs, underscored by their comparatively favorable complication profiles [12, 24]. Additionally, our findings further introduce more benefits, demonstrating through qualitative assessments that leadless PMs result in fewer areas of impact (specify the type of impact, e.g., tissue damage) relative to those observed with transvenous PMs. In addition to short-term complications after implantation of transvenous PM, there are long-term complications such as lead-related venous endovascular infection and tricuspid valve dysfunction. On the contrary, leadless PM eliminate the need for capsule and lead, eliminating the occurrence of capsule hematomas, pain, transvenous infections and dislocation. Patients who require venous access for dialysis and those with postoperative infections following the implantation of transvenous PMs benefit the most from leadless PMs [25]. Lead-related long-term complications can be almost completely avoided in patients with leadless PMs, providing a significant advantage for pacemaker-dependent patients. Previous studies by Wenjie Yang et al. [26, 27] focused on the influence of metallic artifacts during CCTA on the assessment of postoperative complications and the prediction of atrial fibrillation recurrence. Building on these previous studies, our study performed a subjective assessment of the affected areas by artifacts from leadless PM or transvenous PM, especially the leadless PM, we found that artifacts produced by pacemaker in the heart could affect ventricular muscle, epicardial adipose tissue and pericoronary adipose tissue. Assessing postoperative complications and atrial fibrillation invariably proves more challenging in these patients.

Our results demonstrated that SEMAR enabled excellent artifacts reduction for cardiac PMs, especially in leadless PMs. The objective assessment showed the SEMAR group exhibited significantly lower AIs than the non-SEMAR group; also, the subjective assessment showed the subjective scores for artifact extent and diagnostic confidence to be higher in the SEMAR group; still more, compared to transvenous PM after SEMAR, the subjective scores of artifact extent and diagnostic confidence for leadless PM after SEMAR were higher. SEMAR has positive effect for artifact reduction on leadless PM than transvenous PM, to this point, probably because the shape of leadless PM is blocky, with large diameter and shorter overall length than transvenous PM, and the metallic artifacts are relatively concentrated. According to a recent study [24], SEMAR performed better for the evaluation of metal implants with diameter of 2 mm and more, which indirectly supports the above speculation. In addition, SEMAR resolved metallic artifacts in the proximal right coronary artery and facilitate the diagnosis of coronary artery disease. It was also used to assess the lead position of transvenous PMs, clarify the presence of cardiac perforation, and obtain clear images of the pericoronary adipose tissue (PCAT) in the right coronary artery and left anterior descending coronary artery. Furthermore, SEMAR improved visualization of the distal left anterior descending coronary artery and ventricular muscle and overcome the difficulty in obtaining accurate parameters of PCAT affected by metallic artifacts from leadless PMs, as illustrated in Fig. 3.

Metallic artifacts primarily impaired such areas as LAD, RA, RV, LV, EAT, and PCAT. The subjective assessment of artifacts-impaired areas appeared to be an improvement in the SEMAR group compared to the non-SEMAR group. Of note, pacemaker artifacts hardly influenced the LCX and aorta, while the RCA was almost completely unimpaired by the leadless PM’s artifacts, and the impaired areas would even less by SEMAR. Such cases that were difficult to diagnose with traditional algorithms now can be identified and be more obvious in patients with leadless PM. However, the quantitative assessment related to the artifact reduction between leadless PM and transvenous PM did not show significant differences, which did not exclude the factor of small sample size.

Limitations

Our study has some limitations. First, the sample size was relatively small. This study was conducted in a single center, and further multicenter studies on larger patient populations are necessary to verify the clinical significance of our results. Secondly, new artifacts were found to arise after SEMAR in areas severely affected by artifacts, which were not further explored in this study. Thirdly, there was no detailed classification of the postoperative complications involved in the study, and the diseases were not explored separately. Finally, future studies need to evaluate whether SEMAR can improve the diagnostic performance of PM-related complications and patient outcome.

Conclusion

In summary, SEMAR can reduce metallic artifacts from both types of cardiac PMs. Furthermore, leadless PMs exhibited fewer artifact extent and artifacts-impaired tissues compared to transvenous PMs, both prior to and after SEMAR application. This results in a clearer depiction of the tissue anatomy surrounding leadless PMs and improves the diagnostic quality of tissues adjacent to the PMs.

Abbreviations

AI

Artifact index

CCTA

Coronary computed tomography angiography

EAT

Epicardial adipose tissue

HIR

Hybrid-iterative reconstruction

ICC

Intraclass correlation coefficient

LAD

Left anterior descending

LCX

Left circumflex

LV

Left ventricle

PCAT

Pericoronary adipose tissue

PM

Pacemaker

RA

Right atrium

RCA

Right coronary artery

ROI

Region of interest

RV

Right ventricle

SEMAR

Single-energy metal artifact reduction

Author contributions

Y H collected cases and wrote the paper, Y C completed the image post-processing, J H and L Z conducted data analysis, Y L, Q L, Y Y, and H Q carried out the experimental investigation and translated the paper. Z Z, J Z, and M X provided technical support, while Y X revised the paper. All authors reviewed the manuscript.

Funding

This study was funded by the National Natural Science Foundation of China (Grant No.82160334), Tianshan Talent Training Program (TSYC202301B009).

Data availability

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This prospective study was approved by the institutional Ethics Committee of the First Affiliated Hospital of Xinjiang Medical University (No. 220120-02) and all written informed consent was obtained. The study was conducted in accordance with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.