BACKGROUND: Cardiac allograft vasculopathy (CAV) remains a major cause of morbidity and mortality after orthotopic heart transplantation. Although positron emission tomography myocardial perfusion imaging with quantitative myocardial blood flow (MBF) effectively detects CAV, access remains limited. Cadmium-zinc-telluride (CZT) single-photon emission computed tomography (SPECT) enables quantitative MBF assessment and may provide a more accessible alternative. However, the diagnostic and prognostic value of quantitative CZT SPECT-derived MBF for CAV is unknown. METHODS: We retrospectively studied 110 consecutive orthotopic heart transplantation recipients who underwent coronary angiography and CZT SPECT quantitative MBF imaging within 12 months. Stress MBF, rest MBF, MBF reserve, coronary flow capacity, and total perfusion deficit were compared across International Society for Heart and Lung Transplantation CAV categories. The diagnostic performance of the established (Bravo) and modified (Hart) flow-based algorithms was evaluated by receiver operating characteristic analysis. Associations with CAV-related events were assessed. RESULTS: Over 2.3±1.0 years, stress MBF declined progressively with increasing CAV severity ( P =0.007) and was lower in patients with CAV 2 to 3 than in those with CAV 0 to 1 (1.25±0.52 versus 2.03±0.81 mL/min per g; P =0.003). The Bravo and Hart algorithms showed similar discrimination of advanced CAV by paired DeLong comparison (area under the curve, 0.773 versus 0.717; Δ area under the curve, 0.056; P =0.606). Severely reduced coronary flow capacity was associated with higher event rates (28.6% versus 5.2%; P =0.015). The Hart framework demonstrated exploratory prognostic separation (35.3% versus 3.2%; P =0.001). CONCLUSIONS: Quantitative CZT SPECT-derived MBF and coronary flow capacity provide physiological assessment and risk stratification of CAV, with preliminary associations with CAV-related events. These findings support the prospective multicenter evaluation of CZT SPECT MBF as a widely available, noninvasive orthotopic heart transplantation surveillance strategy.
BACKGROUND:Technetium-based cardiac amyloid radionuclide imaging enables noninvasive diagnosis of transthyretin amyloid cardiomyopathy (ATTR-CM), but conventional planar and visual semiquantitative approaches have important limitations. We developed the quantitative 3-dimensional Mayo 3D Score, defined as the ratio of mean left ventricular myocardial radiotracer uptake to right atrial blood-pool uptake using computed tomography (CT)-fused single-photon emission CT (SPECT) volumes of interest, and sought to validate its diagnostic performance against myocardial pathology. METHODS:Consecutive patients who underwent 99mTc-pyrophosphate SPECT/CT at Mayo Clinic for suspected ATTR-CM between June 2017 and January 2025 with archived myocardial tissue were included. Baseline characteristics, including demographics, echocardiogram, biomarkers, visual semiquantitative, and Mayo 3D Score metrics, were collected. Myocardial specimens underwent histopathologic confirmation of amyloid, with amyloid subtype determination and further semiquantitative grading of amyloid burden and deposition patterns. RESULTS:Among 230 patients (median age, 72 years; 78% male), 107 (47%) had ATTR-CM, of whom 9 had hereditary ATTR-CM. The Mayo 3D Score showed excellent discrimination against pathology (area under the receiver operating characteristic curve, 0.92 [0.88-0.96]), exceeding planar Perugini (0.87 [0.83-0.92]; P=0.006), and heart-to-contralateral lung ratio (0.86 [0.81-0.91]; P=0.004) and comparable to SPECT Perugini (0.90 [0.86-0.94]; P=0.12). A cutoff ≥1.0 yielded 86.0% sensitivity, 92.7% specificity, 91.1% positive predictive value, and 88.4% negative predictive value. Among ATTR-positive cases, the Mayo 3D Score correlated strongly with semiquantitative amyloid burden (Spearman ρ=0.69), was higher in pericellular than nodular deposition patterns (P<0.001), and was not associated with vascular involvement (P=0.42). CONCLUSIONS:In patients with suspected ATTR-CM undergoing 99mTc-pyrophosphate SPECT/CT, the Mayo 3D Score demonstrated superior diagnostic performance compared with planar metrics and comparable to SPECT Perugini, while correlating with myocardial ATTR burden and deposition patterns on pathology. These findings support its integration as a quantitative adjunct within clinical diagnostic ATTR-CM workflows.
BACKGROUND:Mitral valve prolapse (MVP) is a common cardiac condition that is generally benign, yet a subset of affected patients develop malignant ventricular arrhythmias and sudden cardiac death. Female sex and myocardial fibrosis detected by late gadolinium enhancement on cardiovascular magnetic resonance imaging have been proposed as risk factors though their independent contributions to arrhythmic risk remain uncertain. METHODS:We conducted a prospective cohort study of 550 consecutive patients with MVP referred for cardiovascular magnetic resonance at a tertiary academic center between May 2008 and December 2021. Patients with potential confounders, including coronary artery disease, cardiomyopathy, infiltrative disease, or prior cardiac surgery, were excluded. The primary end point was a composite arrhythmic outcome comprising sudden cardiac death, aborted sudden cardiac arrest, and symptomatic sustained or inducible ventricular tachycardia or ventricular fibrillation leading to implantable cardioverter defibrillator placement or ventricular ablation at an MVP-related scar site. RESULTS:Among the 550 patients (median age, 62 [interquartile range, 52-71] years; 50% women), LGE was present in 210 (38%). Over a median follow-up of 4.4 years (interquartile range, 2.8-7.1; 2700 patient-years), 48 patients (8.7%) reached the primary end point. On univariable analysis, both female sex (hazard ratio, 3.33 [95% CI, 1.72-6.44]; P<0.001) and LGE presence (hazard ratio, 3.17 [95% CI, 1.74-5.77]; P<0.001) were significantly associated with arrhythmic events, and both remained independently associated on multivariable analysis. Women with LGE represented the highest-risk subgroup, with a 5-year event-free survival of 76.5%, compared with 98.5% in men without LGE (P<0.001). CONCLUSIONS:In a large prospective cardiovascular magnetic resonance cohort of patients with MVP, female sex and myocardial fibrosis were each independently associated with life-threatening arrhythmic events. Their combination identified a subgroup at particularly elevated risk, highlighting the importance of integrating sex-specific factors and myocardial tissue characterization into MVP risk stratification strategies.
BACKGROUND:Accurate assessment of left ventricular outflow tract (LVOT) gradients is critical for hypertrophic cardiomyopathy management, yet Doppler-based measurements are technically demanding and require expertise. The objective of this work was to develop a multi-view deep learning model capable of classifying LVOT obstruction (>20 mm Hg) using routine 2-dimensional echocardiographic windows without reliance on Doppler imaging. METHODS:We trained and externally validated a cross-attention-based video-to-video fusion framework that integrated EchoPrime-derived video representations from 3 standard transthoracic echocardiographic views to classify LVOT gradients. RESULTS:Training was performed on a derivation cohort (N=1833) from a tertiary care system in the United States, with model performance evaluated on an internally held-out test set (N=275) and a Korean external validation cohort (N=46). Single-view baselines showed limited discrimination (external area under the receiver operating curves, 0.47-0.70). Conversely, the domain-specific foundational model (EchoPrime) achieved superior single-view performance (area under the receiver operating curves, 0.75-0.80 internal; 0.79-0.83 external), highlighting the importance of echo-specific pretraining and temporal modeling. The proposed multi-view fusion further enhanced predictive performance, with the late fusion model reaching an area under the receiver operating curve of 0.84 on the external cohort with significant population-shift. CONCLUSIONS:These results suggest LVOT physiology is encoded in routine 2-dimensional imaging and can be leveraged for clinically relevant gradient classification without Doppler input. The proposed artificial intelligence-guided strategy demonstrates substantial cost savings compared with the screen-all approach. By integrating complementary spatial-temporal information across multiple views, our approach generalizes robustly across populations and may enable real-time decision support, extend LVOT assessment to portable or resource-limited settings, and complement Doppler-based evaluation for longitudinal hypertrophic cardiomyopathy management.
Cardiovascular imaging plays a central role in the diagnosis, risk stratification, and longitudinal management of cardiovascular disease during pregnancy. Physiological adaptations—including increased blood volume, cardiac output, and chamber remodeling—pose important challenges for image acquisition and interpretation, necessitating a nuanced understanding of normal versus pathological findings. This review provides a practical, cardiology-focused framework for the use of imaging in pregnant patients with suspected or established cardiovascular disease. We emphasize key aspects relevant to cardiac imagers, including appropriate modality selection, pregnancy-adapted imaging protocols, and interpretation of findings in the context of dynamic physiological changes. Transthoracic echocardiography remains the first-line modality, while cardiovascular magnetic resonance offers complementary, radiation-free evaluation in selected cases. Imaging techniques involving ionizing radiation, such as computed tomography and invasive angiography, should be reserved for acute or high-risk scenarios and carefully optimized to minimize fetal exposure. We further discuss common diagnostic pitfalls, limitations of each modality, and areas of uncertainty, including the use of contrast agents and thresholds for advanced imaging. The importance of integrating imaging findings into multidisciplinary decision-making within Pregnancy Heart Teams is highlighted. By providing a structured, clinically oriented approach, this review aims to support cardiac imagers in delivering safe, accurate, and evidence-informed care to this complex patient population.
BACKGROUND:Right atrioventricular coupling index (RACI), defined as the ratio of right atrial (RA) to right ventricular (RV) end-diastolic volume on cardiac magnetic resonance, is a novel parameter that reflects RA-RV hemodynamic interplay. Its prognostic value in functional tricuspid regurgitation (TR) is unknown. METHODS:This study included 633 consecutive patients with moderate or greater functional TR undergoing cardiac magnetic resonance. Patients were stratified into 2 groups based on the optimal cutoff by the Youden index (normal: RACI<0.62 versus high: RACI≥0.62). The primary outcome was all-cause mortality. RESULTS:Patients with high RACI (n=147) were older (74.1±10.7 years versus 60.6±16.1 years, P<0.001) with larger RA volumes (RA end-systolic volume index: 96.7 [interquartile range, 77.5-121.2] mL/m2 versus 55.4 [interquartile range, 42.6-69.0] mL/m2; P<0.001), smaller RV size (RV end-diastolic volume index: 106.2±33.5 versus 114.8±37.2 mL/m2; P=0.012), and no difference in RV function (RV ejection fraction: 46.3±9.8% versus 45.4±12.7%; P=0.43). Over a median follow-up of 2.9 years (interquartile range, 0.7-6.9), a high RACI was associated with increased mortality risk (25% versus 15%; hazard ratio, 2.06 [95% CI, 1.47-2.90]; P<0.001). In multivariable Cox regression analysis adjusting for age, right and left heart size and function, and clinical markers of right-sided congestion (glomerular filtration rate <30, total bilirubin), RACI remained an independent predictor of all-cause mortality (adjusted hazard ratio, 1.16 per 0.10 increase, 95% CI, 1.03-1.32, P=0.014). In addition, RACI provided incremental prognostic value for predicting the primary outcome over conventional right heart indices (RA and RV volumes, RV ejection fraction, TR severity), improving model performance (χ2 increased from 28.5 to 37.6; P=0.003). CONCLUSIONS:RACI is a novel parameter that effectively integrates RA and RV remodeling, and independently predicts all-cause mortality in functional TR. Incorporating RACI into clinical assessment may help with improving risk stratification and guiding the timing of intervention in patients with functional TR.
Fetal ultrasound is the primary screening modality for routine prenatal examinations, but its effectiveness can be influenced by factors such as maternal body habitus, polyhydramnios, or fetal position. Although magnetic resonance imaging (MRI) is well established for fetal brain and body imaging, cardiac assessment has been restricted by the absence of reliable cardiac gating and motion compensation strategies. Only recently have advances in fetal cardiac rhythm monitoring within the MRI scanner enabled retrospective gating, paving the way for clinical use of fetal cardiac MRI. However, a reproducible and standardized imaging protocol for systematic cardiac assessment on cine sequences has not yet been universally adopted. This article proposes a practical framework for fetal cardiac cine MRI acquisition and interpretation based on a segmental approach consistent with standard fetal echocardiographic orientations, while also incorporating ungated T2-weighted imaging with slice-to-volume reconstruction for the assessment of extracardiac vascular anatomy. Representative cases with annotated anatomic landmarks illustrate how MRI can be integrated into a multimodality prenatal imaging strategy. The development of a standardized protocol may facilitate reproducibility across centers and support the incorporation of fetal cardiac MRI as a complementary tool within comprehensive prenatal cardiac evaluation.
BACKGROUND:The pathogenesis of Takotsubo syndrome (TTS) is poorly understood, but differences in outcome depending on the triggering factor imply differences in the pathophysiology. Beyond the established trigger-based InterTAK (International Takotsubo Registry) classification, the newly proposed distinction between primary and secondary TTS aims to differentiate emotionally primed heart dysfunction from TTS driven by direct myocardial injury. To explore these potential differences, we utilized cardiovascular magnetic resonance imaging to assess left ventricular function, myocardial edema, and myocardial injury across the InterTAK classification and between primary and secondary TTS. METHODS:For this multicenter cohort study, 110 patients (95% women, age 66±12 years) from the InterTAK registry were included who received cardiovascular magnetic resonance 3 (interquartile range, 2-5) days after symptom onset. Cardiovascular magnetic resonance included assessment of myocardial function, edema (T2-weighted spin-echo and T2-mapping when available), and late gadolinium enhancement. RESULTS:No significant differences were observed in left ventricular volumes, function, or mass across the 3 InterTAK groups or between primary and secondary TTS. Patients with emotional triggers exhibited significantly larger myocardial edema (72% versus 60% for physical triggers; P<0.01), supported by higher T2-mapping values in a subset of 22 patients with T2-mapping. In multivariable regression, only emotional trigger (P<0.01) and the absence of coronary artery disease (P=0.04) were independently associated with the extent of myocardial edema. Secondary TTS showed a higher prevalence of focal or patchy late gadolinium enhancement (primary 19%, secondary 54%; P<0.01). In multivariable logistic regression, secondary TTS (P<0.01) and early cardiovascular magnetic resonance (P=0.02) were associated with the presence of any late gadolinium enhancement. CONCLUSIONS:TTS due to emotional stress is associated with larger myocardial edema, and secondary TTS exhibited late gadolinium enhancement more frequently, indicative of direct myocardial damage. These findings suggest that emotionally primed heart dysfunction and direct myocardial injury contribute to TTS pathophysiology to varying extents, influenced by both the triggering factor and preexisting conditions.
BACKGROUND:Aortic enlargement is a powerful predictor of dissection and rupture, yet it is rarely evaluated during routine myocardial perfusion imaging, despite the widespread availability of computed tomography (CT) attenuation correction scans. The aim of this study was to determine whether fully automated, opportunistically derived, artificial intelligence-based aortic measurements from myocardial perfusion imaging CT attenuation correction scans are associated with adverse outcomes in a large multicenter cohort. METHODS:CT attenuation correction scans from patients undergoing positron emission tomography/CT and single-photon emission CT/CT myocardial perfusion imaging across 10 centers were included. A deep learning model automatically segmented the thoracic aorta, and a postprocessing algorithm extracted maximum ascending and descending diameters. The aortic size index was calculated by indexing the diameter to body surface area. RESULTS:A total of 29 339 patients (56% men; median age, 66 years [interquartile range, 58-75 years]) were included. Over a median follow-up of 3.5 years (interquartile range, 1.9-5.0 years), 5083 (17.3%) patients died. Median ascending and descending aortic size index values were 1.8 cm/m2 (interquartile range, 1.6-2.0) and 1.5 cm/m2 (interquartile range, 1.4-1.6), respectively, with an increase with age and higher values in females. Elevated aortic size index thresholds (ascending >2.2 cm/m2; descending >1.6 cm/m2) were significantly associated with increased all-cause mortality (ascending: adjusted hazard ratio, 1.16 [95% CI, 1.07-1.26], P<0.001; descending: adjusted hazard ratio, 1.23 [95% CI, 1.14-1.31]; P<0.001). Notably, the prognostic value of an abnormal aortic size index persisted independent of age, sex, and perfusion abnormalities. CONCLUSIONS:Artificial intelligence can unlock previously unused information within routine myocardial perfusion imaging CT attenuation correction scans by rapidly and automatically quantifying aortic size at scale. Opportunistic aortic measurements derived from CT attenuation correction may serve as an adjunctive risk biomarker and could add prognostic value to standard myocardial perfusion imaging without additional imaging or radiation.
BACKGROUND:Right ventricular-pulmonary arterial coupling is a known prognostic marker in patients with tricuspid regurgitation (TR). However, its assessment by cardiac magnetic resonance and its clinical implications have not been evaluated. We aimed to assess the prognostic role of a cardiac magnetic resonance surrogate of right ventricular-pulmonary arterial coupling in a large cohort of patients with a spectrum of TR severity. METHODS:Comprehensive data were collected from patients referred for cardiac magnetic resonance from 2019 to 2024 who had TR quantification. Right ventricular-pulmonary arterial coupling was calculated by dividing the forward right ventricular stroke volume (f-RVSV) by the right ventricular end-systolic volume (ESV). The outcome of interest was the composite of all-cause death and heart failure hospitalization, under medical management. RESULTS:In the 631 patients included, median age was 66 (interquartile range [IQR], 54-75) years, median tricuspid regurgitant volume was 18 (IQR, 12-30 mL), median left ventricular ejection fraction was 53 (IQR, 41-61)%, median RV ejection fraction was 53 (IQR, 45-58)%, and median f-RVSV/ESV ratio was 0.82 (IQR, 0.58-1.11). In restricted spline curve analysis, the f-RVSV/ESV ratio cutoff associated with a hazard >1 for the composite outcome was ≤0.57. At baseline, a low f-RVSV/ESV ratio was strongly associated with subjective and objective signs of right heart failure, higher TRI-SCORE, and worse right-sided chamber remodeling (all P<0.001). After a median follow-up of 1.8 years (IQR, 1.5-2.0), patients with a low f-RVSV/ESV ratio showed worse survival (P<0.001). After comprehensive adjustment for clinical and imaging confounders, f-RVSV/ESV ≤0.57 remained a powerful predictor of outcome (adjusted hazard ratio, 2.36 [95% CI, 1.27-4.37]; P=0.004). Finally, patients with low f-RVSV/ESV displayed a worse long-term prognosis across mild, moderate, and severe TR groups (P<0.001, P<0.001, and P=0.018, respectively). CONCLUSIONS:In this large cohort of patients with a wide spectrum of TR severity, right ventricular-pulmonary arterial coupling assessed by cardiac magnetic resonance was strongly associated with right-sided heart failure and worse long-term prognosis, even after comprehensive adjustment.
The assessment of left ventricular diastolic function started with invasive pressure measurements and is currently primarily based on echocardiographic imaging. The current approach to the diagnosis of diastolic function relies on mitral inflow velocities, tissue Doppler early diastolic velocity of the mitral annulus, peak velocity of tricuspid regurgitation, pulmonary vein flow, left atrial size and function, and the noninvasive estimation of right atrial pressure. The recommended algorithm in the 2025 American Society of Echocardiography guidelines for estimation of mean left atrial pressure has been validated in a large multicenter study that included 951 patients. Further, that algorithm has shown incremental value to triaging clinical scores in achieving accurate heart failure with preserved ejection fraction diagnosis, against the invasive gold standard. Newer promising approaches have been developed over the past few years to study left ventricular diastolic function, including shear wave propagation velocity, left atrial conduit volume, and timing of mitral and tricuspid valve opening in the apical 4-chamber view. Artificial intelligence has been applied to this field as a rule-based decision tree algorithm, and as deep-learning neural networks to train models for diagnosing and grading diastolic dysfunction, and for diagnosing heart failure with preserved ejection fraction.
BACKGROUND:Primary aldosteronism (PA) carries excess cardiovascular risk not fully explained by hemodynamic load. While aldosterone promotes fibroblast activation experimentally, in vivo evidence linking adrenocortical activity with myocardial remodeling remains limited. This study integrated CXCR4 (C-X-C chemokine receptor type 4)-targeted 68Ga-Pentixafor positron emission tomography (PET)/magnetic resonance and FAP (fibroblast activation protein)-targeted 68Ga-FAPI (fibroblast activation protein inhibitor)-04 PET/cardiac magnetic resonance to evaluate the adrenal-cardiac axis in PA. METHODS:Eighty-two participants (40 with PA [21 aldosterone-producing adenoma (APA), 19 idiopathic hyperaldosteronism], 21 with essential hypertension, and 21 normotensive controls) underwent 68Ga-FAPI-04 PET/cardiac magnetic resonance; 48 concurrently underwent 68Ga-Pentixafor PET/magnetic resonance. Adrenal CXCR4 and myocardial FAPI uptake, as well as integrated volumetric-uptake burdens, were quantified and correlated with clinical and cardiac magnetic resonance indices. Eight patients with APA underwent follow-up imaging postadrenalectomy. RESULTS:Adrenal volume-adjusted CXCR4 signal served as a reliable marker of in vivo aldosterone burden and was significantly associated with adverse left ventricular remodeling, independent of blood pressure levels or hypertension duration. Myocardial 68Ga-FAPI-04 uptake was detected in 55% of patients with PA (APA 71.4%, idiopathic hyperaldosteronism 36.8%), compared with 19% of patients with essential hypertension and 0% of controls (P<0.001), localizing predominantly to the basal septum. Importantly, total adrenal volume-adjusted CXCR4 signal correlated with myocardial FAPI activity (r=0.38-0.64; all P<0.05) and cardiac magnetic resonance markers of remodeling, both of which were positively associated with aldosterone levels. At 5.2±1.2 months post-adrenalectomy, myocardial FAPI uptake in 8 patients with APA declined significantly (P<0.01), whereas late gadolinium enhancement and global cardiac function showed no significant change. CONCLUSIONS:Dual-tracer PET/magnetic resonance provided in vivo molecular evidence of a CXCR4-FAP-mediated adrenal-cardiac axis in PA, revealing cross-talk between adrenocortical function, aldosterone secretion, and myocardial fibroblast activation beyond blood pressure effects. FAPI PET demonstrated more severe myocardial activation in APA, with partial postadrenalectomy reversibility, underscoring the value of early diagnosis and timely surgical intervention. REGISTRATION:URL: https://www.clinicaltrials.gov; Unique identifier: NCT06756737.
