Image quality of cardiac MRI in pediatric and adult patients with congenital heart disease and cardiac implantable electronic devices

Background: The safety of cardiac magnetic resonance (CMR) imaging in patients with cardiac implantable electronic devices (CIEDs), including pacemakers (PMs) and implantable cardioverter-defibrillators (ICDs), have been increasingly recognized. However, CMR utility in this population may be limited by device-related artifacts. This study evaluated the extent of such artifacts in children and adults with congenital heart disease across different PM and ICD subtypes and compared image quality among various CMR sequences.

Methods: A retrospective review identified 23 patients (Table 1) with CIEDs who underwent 29 CMR examinations at Boston Children's Hospital. Patient age at examination ranged from 5 months to 65 years. All examinations were performed using a 1.5T Philips scanner under an established safety protocol. Steady-state free precession (SSFP) and gradient-echo (GRE) cine sequences were evaluated in mid-cavity short-axis (SA) planes. Late gadolinium enhancement (LGE) imaging was performed in 10 of the 29 studies, with 4 of these utilizing a wideband inversion pulse sequences in addition to conventional LGE imaging. Myocardial segments were assessed for the presence of LGE and image artifacts. Two readers independently and subjectively graded overall image quality (IQ). Susceptibility artifacts on cine imaging were further quantified using standardized scoring systems: a 5-point Likert scale for cine images assessing coexisting motion artifacts, the impact of artifacts from the CIEDs on endocardial edge definition, and blood–myocardial contrast (1= non-diagnostic, 2= nearly non-diagnostic, 3= diagnostic with some artifact; 4= diagnostic with almost artifact free images, 5 = diagnostic with excellent IQ and no artifacts) . A separate 4-point Likert scale for LGE images was utilized (1 = poor; 2 = fair; 3 = good; 4 = excellent). Mean scores between the observers were used for comparison.

Results: Of the 29 CMR examinations, 23 included SSFP cine imaging, of which 9 were deemed of inadequate diagnostic quality (IQ scores < 3). In 8 of the 9 of these cases, GRE cine sequences were subsequently performed, resulting in improved diagnostic image quality (IQ scores ≥ 3). Six studies were performed using GRE sequences only with adequate diagnostic quality (IQ scores ≥ 3). Among the 10 LGE examinations, 8 demonstrated adequate diagnostic quality (IQ scores ≥ 3). Wideband sequences were applied in 4 of the LGE studies, with 2/4 showing further improvement in diagnostic quality. The majority of susceptibility artifacts originated from the generator rather than the pacemaker leads. Inter-observer agreement was high. The two observers’ IQ scores were identical or differed by 1 point in 21% of the ratings.

Conclusion: CMR imaging with diagnostic IQ can be performed in pediatric and adult patients with congenital heart disease and a CIED. In patients with image quality degradation on SSFP cine and standard LGE sequences, the use of GRE cine and wideband LGE sequences improved IQ.

Table 1: Baseline characteristics

 

	Values
Male	16 (55%)
Mean age, years Mean body surface area, m2	30.74 ± 18.42 1.79 ± 0.49
Mean heart rate, bpm	78.29 ± 13.94
Left ventricular end-diastolic volume index, mL/m2 Left ventricular end-systolic volume index, mL/m2 Left ventricular ejection fraction, %	42.42 ± 39.60 62.09 ± 62.30 57.26 ± 16.67
Right ventricular ejection fraction, %	50.75 ± 20.96
Diagnosis Conotruncal defect Septal defect Valvular dysfunction Cardiomyopathy Primary arrhythmia Anomalous pulmonary venous return Obstructive left heart lesion   Device type Pacemaker Implantable cardioverter-defibrillator   Lead type Transvenous Epicardial Subcutaneous   Location of generator Left anterior chest Left posterior chest Left abdomen Right anterior chest Epicardial leads with no generator	17 1 3 1 4 1 2     17 10     19 8 2     17 2 3 2 3

Comparison of image quality scores (mean value from 2 observers) for motion artifact, endocardial edge definition, and blood-to-myocardial contrast between SSFP and GRE cine acquisition sequences
Fig. 1: (A) SSFP and (B) GRE cine images in the mid-cavity ventricular short-axis plane in a patient with a subcutaneous implantable cardioverter defibrillator. Artifact from the generator positioned in the left posterior chest is noted at the right side of the image. Reduction of artifact with the GRE sequence allows for improved assessment of left ventricular myocardium.
Fig. 2: Panel (A) standard and (B) wideband grey-blood late gadolinium enhancement images in 4 sequential slices in the mid-cavity left ventricular short-axis plane. Artifact from the generator positioned in the left anterior chest is noted at the top of the image. Reduction of artifact with the wideband LGE technique allows for improved assessment of left ventricular myocardium.