PURPOSE:To compare the image quality and acquisition time of thoracic great vessels using a novel, 3D isotropic non-contrast-enhanced MR angiography that combines respiratory compensation, electrocardiogram-triggering, compressed sensing, and Dixon water-fat separation at 3T (CS-MRA) to a conventional MRA employing parallel imaging and spectral attenuated inversion recovery (cMRA). METHODS:This study included 20 healthy volunteers and 19 patients with thoracic vascular diseases. All scans were performed on a 3T MRI scanner using a T2-prepared 3D fast low angle shot (FLASH) sequence. Visual image quality of thoracic great vessels was assessed using a 4-point scale. Quantitative parameters including SNR, contrast-to-noise ratio (CNR), contrast ratio (CR), and coefficient of variation (CV) were evaluated. Aortic diameters were measured, and reproducibility was assessed using Bland-Altman analysis and the intraclass correlation coefficient (ICC). Image acquisition times were also compared. RESULTS:Visual assessment demonstrated significantly higher scores with CS-MRA compared to cMRA across all evaluated thoracic vessels in both volunteers and patients (median score: 3 vs. 2, P < 0.05). Quantitative analysis showed that CS-MRA yielded significantly higher SNR, CNR, and CR (P < 0.05 for all), along with better signal homogeneity (lower CV). CS-MRA showed excellent intra- and inter-observer agreement for aortic diameter measurements, with ICCs ≥ 0.91 in volunteers and ≥ 0.95 in patients. CS-MRA also achieved significantly shorter acquisition times (volunteers: 5.3 ± 1.4 min vs. 6.0 ± 1.7 min, P < 0.01; patients: 5.1 [4.6-6.3] min vs. 6.9 [5.0-9.6] min, P < 0.01). CONCLUSION:CS-MRA provides superior image quality, comparable measurement reproducibility, and significantly reduced acquisition times compared to cMRA. These findings support the clinical utility of CS-MRA as an efficient and reliable non-contrast technique for thoracic vascular evaluation.

Aims:Left atrial (LA) myopathy is a key driver of atrial fibrillation (AF) development and progression. Late gadolinium enhancement (LGE) cardiovascular magnetic resonance enables non-invasive quantification of LA fibrosis, a hallmark of atrial myopathy. However, conventional LGE sequences lack sufficient spatial resolution to accurately depict the thin atrial wall, and reference data in healthy cohorts are scarce. This study aimed to evaluate a high-resolution isotropic 3D LGE Dixon sequence for assessing LA fibrosis in healthy controls and AF patients. Methods and results:In this prospective study, 40 ablation-naïve AF patients (21 paroxysmal, 19 persistent) and 20 healthy controls underwent isotropic (1.3 mm3) 3D whole-heart LGE imaging. Segmentation was successfully performed using CemrgApp in all participants. A setup-specific threshold for fibrosis detection was defined as an image-intensity ratio (IIR) > 1.34 (mean + 2SD of healthy controls) and validated against pre-procedural electroanatomical mapping (EAM) and follow-up imaging at six months post ablation. At baseline, total LA enhancement was higher in persistent than paroxysmal AF (3.65% [1.84-7.16] vs. 1.16% [0.43-2.27]; P = 0.044) and controls (1.25% [0.65-1.75]; P = 0.041). No significant correlation was observed between total LGE-derived fibrosis and bipolar low-voltage area (ρ = -0.03, P = 0.87), though point-by-point analysis showed a weak negative correlation (ρ = -0.05, P < 0.001). In patients with sinus rhythm at follow-up, total fibrosis increased from 1.68% [0.64-6.51] to 6.30% [2.53-12.28]; P < 0.001, driven by peri-ablational scar formation, with no change in remote myocardium. Intra-reader correlation for LA-LGE was excellent: ICC 0.99 (95% CI 0.95-0.99). Conclusion:High resolution isotropic 3D LA-LGE enables robust detection of ablation-induced scarring and biologically plausible fibrosis differences between AF stages. However, its correlation with bipolar voltage mapping remains limited, suggesting that LGE and EAM provide complementary information on atrial myopathy.

PURPOSE:The goal of this study was to develop a 5-min 3D MRA acquisition at 0.55 T with predictable scan time, 100% data efficiency, and robust water-fat separation. METHODS:For full data efficiency, the proposed method combined self-gating with retrospective motion correction while ensuring a predictable 5-min scan time. Water-fat separation was implemented using a model-based Dixon reconstruction. Evaluation in 18 volunteers compared results to navigator-gated reference scans with nominal scan times of 5 and 10 min via a Likert scale blinded expert rating. Susceptibility to irregular breathing patterns was also analyzed. RESULTS:The expert rating for image quality was 4.22 for the proposed method, 3.89 for the 5-min navigator-gated scan and 4.43 for the 10-min navigator-gated scan. Ranking the three methods revealed moderate inter-rater reliability of 0.46, suggesting only minor differences. While navigator-gated acquisitions deviated from the expected scan time by -2.26 to 2.86 min and -3.91 to 4.54 min for the 5- and 10-min protocols respectively, the proposed method deviated only by -0.17 to 0.45 min. The self-gated method further avoided saturation artifacts from the cross-beam navigator, allowing better distinction of the right pulmonary veins. Image quality for the proposed method was also less susceptible to irregular breathing patterns. CONCLUSION:Whole-thorax MRA acquisitions with water-fat separation and predictable scan times were successfully acquired in 18 volunteers at 0.55 T. The proposed method demonstrated on average better image quality than navigator-gated acquisitions of the same nominal scan time while mitigating limitations of prospective navigator gating.

Objectives Magnetic resonance imaging (MRI) is a widely utilized, non-invasive imaging modality for evaluating aortic diseases. In this study, we sought to validate a novel, ECG-gated, non-contrast enhanced cardiovascular magnetic resonance sequence (T2-Prepared GRE and Dixon Water-Fat Separation, T2p GD) in patients with aortic disease — both with and without prior aortic surgery — and to compare its diagnostic performance with that of standard contrast-enhanced MR angiography (CE-MRA). Materials and Methods A total of 55 patients undergoing cardiovascular MRI were recruited, including 26 with and 29 without a history of aortic surgery. The signal-to-noise ratio (SNR) was measured in the aorta, pericardial fat, and myocardial septum, while the contrast-to-noise ratios (CNR) between the aorta and septum, and the aorta and fat, were calculated for both imaging methods, stratified by surgical history. Additionally, diameters of the aorta and coronary arteries were assessed. The diagnostic quality of the images was evaluated using a five-point Likert scale. Results While the SNR in the aorta was comparable between sequences, the new sequence provided higher SNR in both the septum and pericardial fat, as well as a significant increase in the aorta-to-fat CNR. Prior aortic surgery did not affect SNR or CNR values overall; however, in the water-only images of the new sequence, CNR between the aorta and fat was significantly lower in patients with prior surgery. Vascular diameters measured with the T2p GD sequence were consistently larger, as CE-MRA only assesses the endoluminal borders, while the T2p GD sequence includes anatomic delineation of the vessel wall. Qualitative image assessment revealed that the new sequence achieved higher overall quality ratings and superior subjective delineation, enabling more accurate measurement of the aortic sinus and the proximal third of the coronary arteries across all readers. Conclusions The novel T2p GD sequence enables detailed anatomic characterization of the aorta and coronary arteries and a higher CNR than conventional CE-MRA, even in patients with a history of aortic surgery.

BACKGROUND:Automation in cardiovascular magnetic resonance (CMR) scans holds the potential to improve examination efficiency and workflow consistency. Prospective clinical evidence validating automated scan workflows in routine CMR practice remains limited. METHODS:In this prospective randomized study, consecutive patients referred for non-stress CMR were assigned to either an automated or a manual free-breathing scanning workflow. The fully automated workflow integrated automated plane prescription of multiple steps required for successful image acquisition. The primary endpoint was total examination time; secondary endpoints included plane prescription accuracy, image quality scores, scanner idle time, and technologist workload. RESULTS:Of 255 screened patients, 221 were included (automated, n = 109; manual, n = 112). All examinations were diagnostically adequate. The automated and manual workflows showed a similarly low incidence of plane prescription misalignment, corresponding to 19.3% (21/109) and 17.9% (20/112) misalignment events per examination, respectively, with no significant difference between groups (0.19 vs. 0.18 events per examination, P = 0.780). No significant differences were observed across imaging planes or technologist experience levels, and image quality scores were comparable between workflows (2.74 ± 0.67 vs. 2.69 ± 0.70, P = 0.547). However, the automated scanning workflow significantly reduced total examination time (19.16 ± 2.32 vs. 21.25 ± 2.25 min, P < 0.001) and scanner idle time (7.80 ± 1.80 vs. 10.12 ± 2.03 min, P < 0.001), with consistent savings across all experience levels. Operator workload was also substantially lower with automated scanning, evidenced by fewer mouse clicks and keystrokes (both P < 0.01). CONCLUSIONS:An automated CMR scanning workflow improves examination efficiency and reduces operator workload without compromising image quality or plane prescription accuracy, supporting its integration in routine clinical CMR practice.

BACKGROUND:Centerline semi-automatic measurements (CSAM) of the thoracic aorta have been shown to reduce interobserver variability of diameter measurements. The purpose of this study is to demonstrate the feasibility and efficiency of non-expert CSAM using contrast-enhanced magnetic resonance angiography (CE-MRA) versus double oblique (DO) multiplanar reformation (MPR) measurements obtained by experts, and to assess CSAM failure rate in subjects with and without thoracic aortic disease (TAD). METHODS:Image-based navigator (iNAV) and variable density sampling with Cartesian spiral-like trajectories (VD-CASPR) framework for non-rigid motion correction and image acceleration were utilized for inversion recovery gradient echo MRA. Thoracic MRA was obtained in 41 TAD subjects and 27 normals and independently analyzed by expert cardiologists for DO MPR measurements; one cardiovascular imaging fellow (CSAM1) obtained CSAM in all subjects; another (CSAM2) obtained CSAM in TAD patients. Nine prior MRA exams were analyzed for CSAM in seven subjects with stable aneurysms. Post-processing efficiency and intra/interobserver agreement were assessed at the sinus of Valsalva (SOV), sinotubular junction (STJ), and ascending aorta (AAO) using intra/interclass correlation coefficients. Contour failures were graded on a four-point scale: 1- failure of ≤25% vessel circumference; 2- 26-50% circumference failure; 3- 51-75% circumference failure; 4- >75% failure. RESULTS:CSAM1 failure rate was 13% and 14% in the TAD and normal cohorts, respectively (p = 0.78). CSAM 2 failure rate was 2% in the TAD cohort. Intraobserver agreement was excellent for both methods. SOV interobserver agreement with DO MPR performed the worst, with the lowest interclass correlation (ICC) for SOV major (vs physician 1) in the normal cohort (ICC = .69). Otherwise, agreement with DO MPR was near excellent. Major diameter interobserver agreement was excellent in the TAD cohort. Efficiency was highest for CSAM2. In stable TAD, baseline and follow-up major diameter measurements were not significantly different. CONCLUSION:Non-expert MRA CSAM is feasible with excellent intraobserver and excellent to near excellent interobserver agreement at the STJ and AAO levels compared to expert DO MPR. CSAM failure rates varied significantly between non-expert readers; inter-study CSAM were overall precise.

PURPOSE:To develop an image reconstruction method that enables increased spatial resolution cardiac T1 mapping in both the end-diastolic and systolic phase, that shows high T1 agreement with the clinical standard. The resolution gain is achieved by increasing the acceleration rate of MOLLI single-shot images to R = 4, while maintaining a sufficiently short acquisition window. METHODS:A modified end-to-end variational network (MappingVN) is proposed. The modifications include a re-ordered sheared-grid sampling pattern, 2D + contrast convolutions and the use of patchwise squeeze-and-excitation layers. The method was evaluated in terms of image quality and T1 agreement with reference MOLLI T1 maps using retrospectively undersampled patient data. Furthermore, the method was additionally evaluated in a prospective setting comparing high-resolution T1 maps (1.14 × 1.14 mm2) to reference T1 maps in standard resolution (1.41 × 2.13 mm2). Finally, the applicability for systolic T1 mapping was explored using increased acceleration to shorten the acquisition window. RESULTS:The MappingVN showed improved SSIM scores of 0.95 and 0.98 on 1.5T and 3 T compared to 0.93 and 0.96 for GRAPPA. In high-resolution end-diastolic T1 maps stronger T1 agreement (MappingVN: -3 ± 69 ms on 1.5T, -11 ± 70 ms on 3T, GRPPA: -9 ± 129 ms on 1.5T, 14 ± 106 ms) could be observed. For systolic T1 mapping the MappingVN reduced the occurrence of motion artifacts. CONCLUSION:The proposed method enables high spatial resolution cardiac T1 mapping in both end-diastolic and systolic phases. Resulting maps show good T1 agreement with the clinical standard and may improve the visibility of small focal lesions while reducing partial volume effects.

Background:Serial assessment of the thoracic aorta with magnetic resonance angiography (MRA) is desirable due to 3D volumetric dataset, high spatial resolution, and lack of ionizing radiation. Electrocardiogram (ECG) gated, contrast-enhanced (CE), inversion recovery gradient echo MRA is efficient and historically provides low artifact burden, but the window for imaging with weak albumin binding extracellular gadolinium based contrast agents is small. Our purpose was to acquire whole-chest gated CE-MRA with 1.2 mm3 resolution using image-based navigator (iNAV) for motion correction/contrast monitoring, and variable density sampling in 4-5 min. Image quality and vessel diameter reproducibility are assessed against time resolved MRA (TR-MRA). Methods:iNAV CE-MRA and TR-MRA were obtained prospectively in 40 patients and reviewed by 3 blinded cardiologists for vessel diameter and image quality rated on a four point scale: (1) non-diagnostic; (2) poor-significant blurring; (3) good-mild blurring; and (4) excellent. Reproducibility and image quality were evaluated using the concordance correlation statistic and Cohen's kappa with mean differences evaluated using paired t-tests and repeat-measures ANOVA. Results:iNAV CE-MRA scan time was 4.2 ± 0.7 min. iNAV CE-MRA quality score was higher (p < .001); average difference was 1.4 ± .08 at the sinus of Valsalva (SOV), 1.3 ± .08 at the sinotubular junction (STJ), and .87 ± .10 at the ascending aorta (AAO). Major/minor diameter interobserver agreement was better for iNAV CE-MRA (SOV ICC = .87-.93; STJ ICC = .95-.96; AAO ICC = .96-.97) vs. TR-MRA (SOV ICC = .69-.82; STJ ICC = .78-.83; AAO ICC = .89), as was intraobserver agreement (SOV ICC = .93-.95; STJ ICC = .94-.96; AAO ICC = .96-.97) vs. TR-MRA (SOV ICC = .81-.88; STJ ICC = .72-.73; AAO ICC = .87-.93). Conclusion:iNAV CE-MRA is feasible within a clinically reasonable scan time, provides superior image quality, and measurement reproducibility vs. TR-MRA.

BACKGROUND:Late gadolinium enhancement (LGE) imaging is considered the imaging reference standard for the diagnosis of myocardial infarction and scarring. The aim of this study is to evaluate a free-breathing high-resolution three-dimensional (3D) Dixon LGE imaging prototype with image navigation (iNAV) in chronic myocardial infarction on a 3T system. METHODS:Consecutive myocardial infarction patients were enrolled to undergo CMR examination between February 2024 and January 2025. LGE protocols included breath-hold two-dimensional (2D) phase-sensitive inversion recovery (PSIR) and free-breathing iNAV 3D Dixon acquisitions. Radiologist image quality scoring, contrast ratio (CR), quantitative LGE assessment, and scan time were obtained and reported. Paired t-tests, Wilcoxon signed-rank tests, and repeated-measures ANOVA were used for the comparison. RESULTS:A total of 32 participants (50 years ± 11; 31 male, 1 female) were included. 3D LGE reduced scan time by 2m9s (3D: 4m34s [3m50s, 5m17s], 2D: 6m43s [5m17s, 7m41s], P<0.001). Overall image quality showed no difference (3D: 4 [3, 4], 2D: 4 [3, 5], P = 0.474). 3D LGE showed a trend toward higher image quality scores (3D: 4 [3, 4], 2D: 3 [2, 4], P = 0.053) in patients with respiratory motion artifacts on 2D images. LGE-to-blood CR was significantly higher in the 3D LGE than the 2D LGE images (P<0.001). LGE mass (P = 0.11) and LGE extent (P = 0.02) showed no significant difference between the 3D and 2D LGE datasets. CONCLUSION:Free-breathing iNAV 3D Dixon LGE is feasible at 3T, achieving comparable image quality and scar quantification to 2D PSIR within shorter scan times. It improves CR and enables simultaneous assessment of myocardial fibrosis and fat infiltration.

PURPOSE:In this work, a 3D phase contrast (PC) technique is presented, which enables flow velocity measurements in three spatial directions, simultaneously covering the proximal left (LCA) and right (RCA) coronary arteries and yielding both morphological and flow information. METHODS:Data is acquired in a single diastolic cardiac phase during free breathing using an isotropic (Δx = 1.2 mm) 3D PC sequence with respiratory gating and compressed sensing acceleration (factor 14). The reference and flow-encoded datasets are obtained from separate scans instead of one interleaved measurement, enabling inter-scan motion correction through image co-registration. The proposed method is validated in a flow phantom and its feasibility is demonstrated in 16 volunteers (8 female, 59.3 ± 16.5 years) and 3 patients (1 female, 71.0 ± 9.6 years) with known CAD, where additional CTA and CT-FFR data were obtained. Data were acquired on a 3 T MRI system and post-processed using in-house developed software. RESULTS:Flow phantom experiments demonstrated good agreement between the proposed method and a typical 4D Flow acquisition. Mean average velocities in the proximal coronary arteries of volunteers were found to be 11.9 ± 3.3 cm s-1 (LCA) and 8.4 ± 2.6 cm s-1 (RCA). For patients, increases in velocities correlated with the locations of stenoses and reduced CT-FFR values. CONCLUSION:The feasibility of 3D-PC-MRI for non-invasive 3D blood flow velocity imaging in the coronary arteries is demonstrated. Simultaneous acquisitions of high-resolution morphology and velocities could offer new opportunities for diagnosing and monitoring CAD.