Improved Diagnostic Confidence for Patients with Cardiac Implants using Wideband Spoiled Gradient Echo-based Single-Shot Late Gadolinium Enhancement Imaging

Background: Late Gadolinium Enhancement (LGE) imaging is a fundamental component of cardiac MRI and remains gold standard for detecting myocardial fibrosis/scarring¹. However, LGE imaging in patients with metallic implants introduces specific technical and safety challenges². Beyond safety and workflow complexities, conventional Steady-State Free Precession-based (SSFP-based) LGE sequences are particularly susceptible to device-related artifacts, which can obscure critical myocardial regions compromising scar visualization. In this study, we aim to demonstrate that wideband Spoiled Gradient Echo-based (SPGR-based) single-shot (ssh) LGE imaging offers significant improvements in scar visualization and diagnostic confidence for patients with various cardiac implants, compared to the routine wideband SSFP-based approach.

Methods: A total of 8 patients were included with detailed implant information summarized in Table 1. In addition to routine functional assessments, back-to-back ssh phase-sensitive LGE imaging was performed using SSFP-based and SPGR-based acquisitions. Both sequences were wideband with 4kHz inversion recovery preparation. Imaging was conducted 10 minutes post-contrast injection in both short-axis (SA) and 4-chamber (4CH) views on a clinical 1.5T MRI scanner (GEHC). All images were reviewed by an experienced cardiac radiologist. Diagnostic confidence was evaluated on a 4-point scale³: 1: no diagnostic confidence; 2: low diagnostic confidence; 3: moderate diagnostic confidence; 4: high diagnostic confidence. The scores were compared with a Wilcoxon test with significance level at 0.01.

Results: Utilization of wideband SPGR-based LGE technique improved diagnostic confidence in both SA and 4CH views. Representative cases are visualized in the Figure 1 and Figure 2 below, showing significant improvement in metal artifact in the SPGR-based versus the conventional SSFP-based protocol despite both being wideband enabled. Despite the small sample size, the diagnostic confidence scores reached statistical significance (p < 0.01), showing higher scores for the SPGR-based approach compared to the SSFP-based approach.

Conclusion: The percentage of adult patients containing a metallic implant continues to increase^4,5. More than 3 million Americans have a pacemaker or defibrillator. Developing pacemaker technology has increased utilization of pacemaker placement to treat arrhythmia induced cardiomyopathies. This patient cohort requires frequent imaging with cardiac MR and the need for high-quality imaging with diagnostic confidence. In this study, we demonstrate that even wideband-enabled SSFP-based LGE can suffer from metallic artifacts. Utilization of SPGR-based LGE can improve diagnostic confidence in more challenging devices. The limitations of this study include a small cohort of patients and devices. Additional studies should be performed with a larger cohort of patients and device types or evaluate optimal delayed enhancement techniques in patients with metallic implants.

Table 1. Patient information

Table 1. Patient information.

Age	Sex	Clinical Indication	Device
48	M	Status Post Heart Transplant	Metal heart transplant wires
40	F	Hypertrophic Cardiomyopathy	ICD
46	M	Status Post Heart Transplant, Right Ventricular Leadless Pacemaker	Leadless Ventricular Pacemaker
61	M	Hypertrophic Cardiomyopathy	ICD
38	F	Arrhythmogenic Right Ventricular Cardiomyopathy	Loop Recorder
57	M	Nonischemic Cardiomyopathy	ICD
50	M	Heart Block Status Post Leadless Pacemaker Placement, evaluate for Infiltrative Etiology	Leadless ventricular Pacemaker
63	M	Infiltrative/inflammatory cardiomyopathy	ICD and LINX

 Figure 1 46-year-old male patient status post heart transplant with a right ventricular leadless pacemaker. (A, C). Conventional SSFP-based single-shot phase-sensitive LGE images in short-axis (A) and 4-chamber (C) views demonstrate significant artifact decreasing diagnostic confidence in the evaluation of the left ventricular septal myocardium. (B, D) SPGR-based single-shot phase-sensitive LGE in the short-axis (B) and 4-chamber (D) views demonstrate improved diagnostic confidence in evaluation of the left ventricular septal myocardium.
Figure 2. 63-year-old male patient with a pacemaker and LINX device in the gastroesophageal junction. (A) SSFP-based single-shot phase-sensitive LGE demonstrating severe degradation of diagnostic confidence secondary to the metal artifact. (B) SPGR-based single-shot phase-sensitive LGE demonstrating significantly improved diagnostic confidence with visualization of the entire left ventricular myocardium.
Figure 3. Comparison of average diagnostic confidence scores between the two methods. The SPGR-based technique scored significantly higher (p < 0.01) than SSFP-based approach in both short-axis and 4-chamber views.