Prognostic value of myocardial deformation parameters for outcome prediction in tetralogy of Fallot.

INTRODUCTION: The prognostic value of myocardial deformation parameters in adults with repaired tetralogy of Fallot (rTOF) has not been well-elucidated. We therefore aimed to explore myocardial deformation parameters for outcome prediction in adults with rTOF using cardiovascular magnetic resonance imaging (CMR). METHODS: Adults with rTOF and at least moderate pulmonary regurgitation (PR) were identified from an institutional prospective CMR registry. Left (LV) and right ventricular (RV) global strain were recorded in longitudinal (GLS), circumferential (GCS) and radial (GRS) directions. Major adverse cardiovascular events (MACE) were defined as a composite of mortality, resuscitated sudden death, sustained ventricular tachycardia (>30seconds) or heart failure (hospital admission >24hours). In patients with pulmonary valve replacement (PVR), pre-and post-PVR CMR studies were analysed to assess for predictors of complete RV reverse remodelling, which we defined as RV end-diastolic volume indexed (RVEDVi) <110ml/m2. Logistic regression models were used to estimate the odds ratio (OR) per unit change in absolute strain value associated with clinical outcomes and receiver operator characteristic (ROC) curves were constructed with area under the curve (AUC) for select CMR variables. RESULTS: We included 307 patients (age 35±13 years, 59% male). During 6.1 years (3.3-8.8) of follow-up, pulmonary valve replacement (PVR) was performed in 142 (46%) and MACE occurred in 31 (10%). On univariate analysis, baseline biventricular ejection fraction (EF), mass and all strain parameters were associated with MACE. After adjustment for LVEF, only LVGLS remained independently predictive of MACE (OR 0.822 [0.693-0.976] p=0.025). Receiver operator curves identified an absolute LVGLS value less than 15 and LVEF <51% as thresholds for MACE prediction (AUC 0.759 [0.655-0.840] and 0.720 [0.608-0.810]). After adjusting for baseline RVEDVi, RVGCS (OR 1.323 [1.094-1.600] p=0.004), LVGCS (OR 1.276 [1.029-1.582] p=0.027) and LVGRS (OR 1.101 [1.0210-1.200], p=0.028) were independent predictors of complete remodelling post-PVR remodelling. CONCLUSIONS: Biventricular strain parameters predict clinical outcomes and post-PVR remodelling in rTOF. Further study will be necessary to establish the role of myocardial deformation parameters in clinical practice.

The effects of pregnancy in subjects with repaired tetralogy of Fallot.

BACKGROUND: Previous reports reveal inconsistent findings of right ventricular (RV) changes following pregnancy in subjects with repaired tetralogy of Fallot (rTOF). METHODS: A two-center, retrospective cohort study which included women with rTOF who completed pregnancy that were matched to nulliparous women with rTOF by age at the time of baseline cardiac magnetic resonance (CMR), RV ejection fraction (RVEF), and indexed RV end-diastolic volume (RVEDVi). Pre-pregnancy and postpartum cardiac magnetic resonance (CMR) were analyzed and compared to sequential CMR of nulliparous subjects with rTOF. RESULTS: Thirty-six women with rTOF who completed pregnancy were matched to 72 nulliparous women with rTOF. Over a mean period of 3.1 years for the pregnancy group and 2.7 years for the comparison group, there was no significant change in the RVEDVi, RVEF, RV mass, pulmonary regurgitation severity, left ventricular (LV) volumes, LV ejection fraction (LVEF), or LV mass when comparing the baseline CMR and the follow-up CMR in either of the groups. There was a slight increase in RV indexed end-systolic volume (RVESVi) when comparing the baseline CMR and the follow-up CMR in the pregnancy group (68.93, SD 23.34 ml/m2 at baseline vs. 72.97, SD 25.24 mL/m2 at follow-up, P = .028). Using a mixed effects model for CMR parameters change over time; when adjusted for time between baseline and follow-up CMR there was no significant difference in rate of change between the pregnancy and comparison groups. CONCLUSIONS: Most ventricular remodeling parameters measured by CMR did not significantly change in subjects with rTOF who completed pregnancy or in nulliparous subjects with rTOF. In the pregnancy group, RVESVi is larger in those individuals who have undergone pregnancy without a significant change in ventricular function. These patients should be followed longitudinally to determine the long-term ventricular and clinical effects of pregnancy.

Cardiovascular magnetic resonance imaging and clinical follow-up in patients with clinically suspected myocarditis after COVID-19 vaccination.

BACKGROUND: The purpose of this study was to evaluate cardiovascular magnetic resonance (CMR) findings and their relationship to longer-term clinical outcomes in patients with suspected myocarditis following coronavirus disease 2019 (COVID-19) vaccination. METHODS: Consecutive adult patients who underwent clinically indicated CMR for evaluation of suspected myocarditis following messenger ribonucleic acid (mRNA)-based COVID-19 vaccination at a single center between 2021 and 2022 were retrospectively evaluated. Patients were classified based on the revised Lake Louise criteria for T1-based abnormalities (late gadolinium enhancement [LGE] or high T1 values) and T2-based abnormalities (regional T2-hyperintensity or high T2 values). RESULTS: Eighty-nine patients were included (64% [57/89] male, mean age 34 ± 13 years, 38% [32/89] mRNA-1273, and 62% [52/89] BNT162b2). On baseline CMR, 42 (47%) had at least one abnormality; 25 (28%) met both T1- and T2-criteria; 17 (19%) met T1-criteria but not T2-criteria; and 47 (53%) did not meet either. The interval between vaccination and CMR was shorter in those who met T1- and T2-criteria (28 days, IQR 8-69) compared to those who met T1-criteria only (110 days, IQR 66-255, p < 0.001) and those who did not meet either (120 days, interquartile range (IQR) 80-252, p < 0.001). In the subset of 21 patients who met both T1- and T2-criteria at baseline and had follow-up CMR, myocardial edema had resolved and left ventricular ejection fraction had normalized in all at median imaging follow-up of 214 days (IQR 132-304). However, minimal LGE persisted in 10 (48%). At median clinical follow-up of 232 days (IQR 156-405, n = 60), there were no adverse cardiac events. However, mild cardiac symptoms persisted in 7 (12%). CONCLUSION: In a cohort of patients who underwent clinically indicated CMR for suspected myocarditis following COVID-19 vaccination, 47% had at least one abnormality at baseline CMR. Detection of myocardial edema was associated with the timing of CMR after vaccination. There were no adverse cardiac events. However, minimal LGE persisted in 48% at follow-up.

Adherence to clinical practice guidelines for pulmonary valve intervention after tetralogy of Fallot repair: A nationwide cohort study.

Objectives: To determine guideline adherence pertaining to pulmonary valve replacement (PVR) referral after tetralogy of Fallot (TOF) repair. Methods: Children and adults with cardiovascular magnetic resonance imaging scans and at least moderate pulmonary regurgitation were prospectively enrolled in the Comprehensive Outcomes Registry Late After TOF Repair (CORRELATE). Individuals with previous PVR were excluded. Patients were classified according to presence (+) versus absence (-) of PVR and presence (+) versus absence (-) of contemporaneous guideline satisfaction. A validated score (specific activity scale [SAS]) classified adult symptom status. Results: In total, 498 participants (57% male, mean age 32 ± 14 years) were enrolled from 14 Canadian centers (2013-2020). Mean follow-up was 3.8 ± 1.8 years. Guideline criteria for PVR were satisfied for the majority (n = 422/498, 85%), although referral for PVR occurred only in a minority (n = 167/498, 34%). At PVR referral, most were asymptomatic (75% in SAS class 1). One participant (0.6%) received PVR without meeting criteria (PVR+/indication-). The remainder (n = 75/498, 15%) did not meet criteria for and did not receive PVR (PVR-/indication-). Abnormal cardiovascular imaging was the most commonly cited indication for PVR (n = 61/123, 50%). The SAS class and ratio of right to left end-diastolic volumes were independent predictors of PVR in a multivariable analysis (hazard ratio, 3.33; 95% confidence interval, 1.92-5.8, P < .0001; hazard ratio, 2.78; 95% confidence interval, 2.18-3.55, P < .0001). Conclusions: Although a majority of patients met guideline criteria for PVR, only a minority were referred for intervention. Abnormal cardiovascular imaging was the most common indication for referral. Further research will be necessary to establish the longer-term clinical impact of varying PVR referral strategies.

Incremental value of machine learning for risk prediction in tetralogy of Fallot.

OBJECTIVE: Machine learning (ML) can facilitate prediction of major adverse cardiovascular events (MACEs) in repaired tetralogy of Fallot (rTOF). We sought to determine the incremental value of ML above expert clinical judgement for risk prediction in rTOF. METHODS: Adult congenital heart disease (ACHD) clinicians (≥10 years of experience) participated (one cardiac surgeon and four cardiologists (two paediatric and two adult cardiology trained) with expertise in heart failure (HF), electrophysiology, imaging and intervention). Clinicians identified 10 high-yield variables for 5-year MACE prediction (defined as a composite of mortality, resuscitated sudden death, sustained ventricular tachycardia and HF). Risk for MACE (low, moderate or high) was assigned by clinicians blinded to outcome for adults with rTOF identified from an institutional database (n=25 patient reviews conducted by five independent observers). A validated ML model identified 10 variables for risk prediction in the same population. RESULTS: Prediction by ML was similar to the aggregate score of all experts (area under the curve (AUC) 0.85 (95% CI 0.58 to 0.96) vs 0.92 (0.72 to 0.98), p=0.315). Experts with ≥20 years of experience had superior discriminative capacity compared with <20 years (AUC 0.98 (95% CI 0.86 to 0.99) vs 0.80 (0.56 to 0.93), p=0.027). In those with <20 years of experience, ML provided incremental value such that the combined (clinical+ML) AUC approached ≥20 years (AUC 0.85 (95% CI 0.61 to 0.95), p=0.055). CONCLUSIONS: Robust prediction of 5-year MACE in rTOF was achieved using either ML or a multidisciplinary team of ACHD experts. Risk prediction of some clinicians was enhanced by incorporation of ML suggesting that there may be incremental value for ML in select circumstances.

Imaging of Cardiac Fibrosis: An Update, From the AJR Special Series on Imaging of Fibrosis.

Myocardial fibrosis (MF) is defined as excessive production and deposition of extracellular matrix (ECM) proteins, resulting in pathologic myocardial remodeling. Three types of MF have been identified: replacement fibrosis from tissue necrosis, reactive fibrosis from myocardial stress, and infiltrative interstitial fibrosis from progressive deposition of non-degradable material such as amyloid. While echocardiography, nuclear medicine, and CT play important roles in the assessment of MF, MRI is pivotal in the evaluation of MF, using the late gadolinium enhancement (LGE) technique as a primary endpoint. The LGE technique focuses on the pattern and distribution of gadolinium accumulation in the myocardium and assists the diagnosis and establishment of the etiology of both ischemic and non-ischemic cardiomyopathy. LGE MRI aids prognostication and risk stratification. In addition, LGE MRI is used to guide management of patients being considered for ablation for arrhythmias. Parametric mapping techniques, including T1 mapping and extracellular volume measurement, allow detection and quantification of diffuse fibrosis, which may not be detected by LGE MRI. These techniques also allow monitoring of disease progression and therapy response. This review provides an update on imaging of MF, including prognostication and risk stratification tools, electrophysiologic considerations, and disease monitoring.

Mitral annular disjunction on cardiac MRI: Prevalence and association with disease severity in Loeys-Dietz syndrome.

BACKGROUND: The purpose of this study was to evaluate mitral annular disjunction (MAD) on cardiac magnetic resonance imaging (MRI) in Loeys-Dietz Syndrome (LDS) and to explore its association with adverse outcomes. METHODS: In this retrospective cohort study, adult patients with LDS who underwent cardiac MRI were evaluated for MAD, aortic dimensions, and ventricular volumetry. Aortic events were defined as aortic surgery and/or dissection and severe arrhythmic events as cardiac arrest or sustained ventricular tachycardia (VT). RESULTS: Among 46 LDS patients (52% female, 37.2 ± 14.3 years), 17 had MAD (37%). MAD and no MAD groups were similar in age, sex, aortic dimensions and left ventricular parameters. After a clinical follow-up of 4.3 years (IQR 1.5-8.4), 3 in MAD and 4 in no MAD groups required aortic valve sparing root replacement (VSRR) and 1 in MAD developed type A dissection. Over a similar imaging follow-up period [4.1 years (IQR 2.7-9.1) vs. 3.2 years (IQR 1.0-9.0), p = 0.65], compared to baseline, increase in native aortic root size was significant only in MAD (39.4 ± 4.6 mm vs. 38.1 ± 5.3 mm, p = 0.02, 19.3 ± 2.4 mm/m2 vs. 18.7 ± 2.4 mm/m2, p = 0.01) compared to those without MAD. Patients with MAD were younger at first aortic event compared to those without (26.7 ± 11.5 years vs. 45.0 ± 14.9 years, p = 0.03). MAD distance correlated with need for VSRR, r = 0.57, p = 0.02. Two patients in the MAD group developed sustained VT. No cardiac arrest or death was observed. CONCLUSION: MAD is highly prevalent in LDS, associated with progressive aortic dilatation, and aortic events at younger age. MAD may be a marker of disease severity necessitating close surveillance.

Machine Learning for Prediction of Adverse Cardiovascular Events in Adults With Repaired Tetralogy of Fallot Using Clinical and Cardiovascular Magnetic Resonance Imaging Variables.

BACKGROUND: Existing models for prediction of major adverse cardiovascular events (MACE) after repair of tetralogy of Fallot have been limited by modest predictive capacity and limited applicability to routine clinical practice. We hypothesized that an artificial intelligence model using an array of parameters would enhance 5-year MACE prediction in adults with repaired tetralogy of Fallot. METHODS: A machine learning algorithm was applied to 2 nonoverlapping, institutional databases of adults with repaired tetralogy of Fallot: (1) for model development, a prospectively constructed clinical and cardiovascular magnetic resonance registry; (2) for model validation, a retrospective database comprised of variables extracted from the electronic health record. The MACE composite outcome included mortality, resuscitated sudden death, sustained ventricular tachycardia and heart failure. Analysis was restricted to individuals with MACE or followed ≥5 years. A random forest model was trained using machine learning (n=57 variables). Repeated random sub-sampling validation was sequentially applied to the development dataset followed by application to the validation dataset. RESULTS: We identified 804 individuals (n=312 for development and n=492 for validation). Model prediction (area under the curve [95% CI]) for MACE in the validation dataset was strong (0.82 [0.74-0.89]) with superior performance to a conventional Cox multivariable model (0.63 [0.51-0.75]; P=0.003). Model performance did not change significantly with input restricted to the 10 strongest features (decreasing order of strength: right ventricular end-systolic volume indexed, right ventricular ejection fraction, age at cardiovascular magnetic resonance imaging, age at repair, absolute ventilatory anaerobic threshold, right ventricular end-diastolic volume indexed, ventilatory anaerobic threshold % predicted, peak aerobic capacity, left ventricular ejection fraction, and pulmonary regurgitation fraction; 0.81 [0.72-0.89]; P=0.232). Removing exercise parameters resulted in inferior model performance (0.75 [0.65-0.84]; P=0.002). CONCLUSIONS: In this single-center study, a machine learning-based prediction model comprised of readily available clinical and cardiovascular magnetic resonance imaging variables performed well in an independent validation cohort. Further study will determine the value of this model for risk stratification in adults with repared tetralogy of Fallot.

Patient-Reported Outcomes After Tetralogy of Fallot Repair.

BACKGROUND: Comprehensive assessment of tetralogy of Fallot (TOF) outcomes extends beyond morbidity and mortality to incorporate patient-reported outcomes (PROs), including quality of life (QOL) and health status (HS). OBJECTIVES: This study explored PROs in adolescents and adults with TOF and delineated variables associated with PROs. METHODS: This was a cross-sectional observational study within a larger prospective registry of adolescents and adults with repaired TOF and moderate or greater pulmonary regurgitation from North America, Europe, and Asia. Participants completed PROs, including a QOL linear analogue scale (QOL-LAS) and an HS visual analogue scale (HS-VAS). Scores were classified according to age cohorts: <18, 18 to 25, 26 to 40, and >40 years. RESULTS: The study included 607 patients (46.3% female; median age 28.5 years). Median QOL-LAS scores (0-100) were similar across age cohorts (85, 80, 80, 80; P = 0.056). Median HS-VAS scores (0-100) were lowest for the oldest cohort (77) compared with the 3 younger cohorts (85, 80, 80) (P = 0.004). With advancing age, there were increased reports of poor mobility (P < 0.001) and pain or discomfort (P = 0.004); problems in these dimensions were reported by 19.1% and 37.2% of patients aged >40 years, respectively. Of factors associated with superior PROs on multivariable regression modeling (ie, being White, being nonsyndromic, having employment, and having better left ventricular function; P < 0.05), asymptomatic status (functional class I) was the variable associated with the greatest number of QOL and HS measures (P < 0.001). CONCLUSIONS: Strategies to improve TOF outcomes should consider PROs alongside conventional clinical variables. Factors associated with poorer PROs represent opportunities to intervene to improve the lives of patients with TOF.

Cardiac Magnetic Resonance Imaging T1 and T2 Mapping in Systemic Lupus Erythematosus in Relation to Antimalarial Treatment.

PURPOSE: Patients with systemic lupus erythematosus (SLE) are at risk of cardiac disease including antimalarial-induced cardiomyopathy (AMIC). The purpose of this study is to evaluate cardiac magnetic resonance imaging parametric mapping findings in SLE patients with AMIC and investigate the relationship of T1/T2 mapping to antimalarial (AM) treatment duration. MATERIALS AND METHODS: All patients with SLE who had undergone cardiac magnetic resonance imaging with T1/T2 mapping for evaluation of suspected cardiac disease between 2018 and 2021 were evaluated and compared with healthy controls. To facilitate comparison between scanners, T1/T2 values were converted to a z -score using scanner-specific local reference values. Patients were classified into 3 groups: AMIC, myocarditis, and other (no AMIC or myocarditis). RESULTS: Forty-five SLE patients (47±17 y, 80% female; 8 [18%] with AMIC and 7 [16%] with myocarditis) and 30 healthy controls (39±15 y, 60% female) were included. Patients with AMIC had higher T1 and T2 compared with controls ( z -score 1.1±1.3 vs. 0±0.6, P =0.01 and 1.7±1.1 vs. 0±1.0, P <0.01, respectively) and lower values compared with those with myocarditis (3.7±1.6, P <0.01 and 4.0±2.0, P <0.01, respectively). T1 correlated negatively with AM treatment duration in patients without AMIC or myocarditis ( r =-0.36, P =0.048) and positively in patients with AMIC ( r =0.92, P =0.001). AM treatment duration did not correlate significantly with T1 in patients with myocarditis or with T2 in any group. CONCLUSIONS: The relationship between T1 and AM treatment duration differed between groups. Native T1 decreases with longer treatment in patients without AMIC or myocarditis, possibility due to glycosphingolipid accumulation. In patients with AMIC, increasing T1 with longer treatment could reflect fibrosis.

Association of Pectus Excavatum With Ventricular Remodelling and Mitral Valve Abnormalities in Marfan Syndrome.

Background: Marfan syndrome (MFS) is an inherited connective tissue disorder. Pectus excavatum (PEX) is common in MFS. The purpose was to evaluate the association of PEX with cardiovascular manifestations of MFS, biventricular size and function. Methods: MFS adults undergoing cardiac MRI were retrospectively evaluated. Exclusion criteria were incomplete cardiac MRI, significant artifacts, co-existent ischaemic or congenital heart disease. Haller Index (HI) ≥3.25 classified patients as PEX positive (PEX+) and PEX negative (PEX-). Cardiac MRI analysis included assessment of mitral valve prolapse (MVP), mitral annular disjunction (MAD), biventricular volumetry and aortic dimensions. Results: 212 MFS patients were included, 76 PEX+ and 136 PEX- (HI 8.3 ± 15.2 vs 2.3 ± 0.5, P < .001). PEX+ were younger (33.4 ± 12.0 vs 38.1 ± 14.3 years, P = .02) and similar in sex distribution (55% vs 63% male, P = .26) compared to PEX-. MVP and MAD were more frequent in PEX+ vs PEX- (43/76 [57%] vs 37/136 [27%], P < .001; 44/76 [58%] vs 50/136[37%], P = .003, respectively). PEX+ had higher right ventricular end-diastolic and end-systolic volumes (RVEDVi 92 ± 17mL/m2 vs 84 ± 22mL/m2, P = .04; RVESVi 44 ± 10 mL/m2 vs 39 ± 14 mL/m2, P = .02), lower RV ejection fraction (RVEF 52 ± 5% vs 55 ± 6%, P = .01) compared to PEX-. Left ventricular (LV) volumes, LVEF and aortic dimensions were similar. Conclusion: MFS adults with PEX have higher frequency of cardiac manifestations including MV abnormalities, increased RV volumes and lower RVEF compared to those without PEX. Awareness of this association is important for all radiologists who interpret aortic CT or MRI, where HI can be easily measured. PEX in MFS may suggest more severe disease expression necessitating careful screening for MV abnormalities and outcomes surveillance.

Imaging of Heritable Thoracic Aortic Disease.

Heritable Thoracic Aortic Disease (HTAD) is caused by mutation of a gene that confers a high risk for thoracic aortic aneurysms and dissections. Syndromic HTAD are associated with systemic manifestations and include Marfan, Loeys-Dietz, vascular Ehlers Danlos and Turner Syndromes. The purpose of this review is to summarize the pathophysiology, cardiovascular imaging features and management of HTAD. Imaging plays an important role in screening for aortic dilatation and monitoring progression. Echocardiogram, Computed tomography and Magnetic resonance imaging are the commonly used modalities. Based on consensus guidelines, prophylactic aortic replacement is indicated when a certain threshold diameter is reached.

Reversal of right ventricular pressure loading improves biventricular function independent of fibrosis in a rabbit model of pulmonary artery banding.

Right ventricular (RV) pressure loading leads to RV and left ventricular (LV) dysfunction through RV hypertrophy, dilatation and fibrosis. Relief of RV pressure load improves RV function. However, the impact and mechanisms on biventricular reverse-remodelling and function are only partially characterized. We evaluated the impact of RV pressure overload relief on biventricular remodelling and function in a rabbit model of reversible pulmonary artery banding (PAB). Rabbits were randomized to three groups: (1) Sham-operated controls (n = 7); (2) PAB (NDef, n = 7); (3) PAB followed by band deflation (Def, n = 5). Sham and NDef animals were sacrificed at 6 weeks after PAB surgery. Def animals underwent PAB deflation at 6 weeks and sacrifice at 9 weeks. Biventricular geometry, function, haemodynamics, hypertrophy and fibrosis were compared between groups using echocardiography, magnetic resonance imaging, high-fidelity pressure-tipped catheters and histology. RV pressure loading caused RV dilatation, systolic dysfunction, myocyte hypertrophy and LV compression which improved after PAB deflation. RV end-diastolic pressure (RVEDP) decreased after PAB deflation, although remaining elevated vs. Sham. LV end-diastolic pressure (LVEDP) was unchanged following PAB deflation. RV and LV collagen volumes in the NDef and Def group were increased vs. Sham, whereas RV and LV collagen volumes were similar between NDef and Def groups. RV myocyte hypertrophy (r = 0.75, P < 0.001) but not collagen volume was related to RVEDP. LV myocyte hypertrophy (r = 0.58, P = 0.016) and collagen volume (r = 0.56, P = 0.031) correlated with LVEDP. In conclusion, relief of RV pressure overload improves RV and LV geometry, hypertrophy and function independent of fibrosis. The long-term implications of persistent fibrosis and increased biventricular filling pressures, even after pressure load relief, need further study. KEY POINTS: Right ventricular (RV) pressure loading in a pulmonary artery banding rabbit model is associated with RV dilatation, left ventricular (LV) compression; biventricular myocyte hypertrophy, fibrosis and dysfunction. The mechanisms and impact of RV pressure load relief on biventricular remodelling and function has not been extensively studied. Relief of RV pressure overload improves biventricular geometry in conjunction with improved RV myocyte hypertrophy and function independent of reduced fibrosis. These findings raise questions as to the importance of fibrosis as a therapeutic target.

Clinical Impact of Cardiac MRI T1 and T2 Parametric Mapping in Patients with Suspected Cardiomyopathy.

Background There are limited data on the incremental value of parametric mapping compared with core cardiac MRI protocols for suspected cardiomyopathy in routine clinical practice. Purpose To evaluate the impact of cardiac MRI T1 and T2 mapping in routine clinical practice with respect to diagnostic accuracy, reader diagnostic confidence, and downstream cardiac imaging utilization. Materials and Methods In this retrospective single-center study, consecutive clinical cardiac MRI scans obtained with and without T1 and T2 mapping for evaluation of suspected cardiomyopathy between January 2017 and October 2019 were evaluated. Diagnostic accuracy and reader diagnostic confidence were evaluated in a random subset. Downstream cardiac imaging utilization was analyzed in patients with a minimum of 1 year of clinical follow-up ending before January 2020. Results A total of 1876 patients (mean age, 51 years ± 17 [SD]; 1113 men) were evaluated. Of these, 751 (40%) underwent cardiac MRI with the core protocol and 1125 (60%) with the core protocol plus T1 and T2 mapping. In the mapping group, T1 and T2 were high in 280 (25%) and 47 patients (4%), respectively. In the subset evaluated for diagnostic utility (n = 450), the addition of T1 and T2 maps to the core protocol resulted in an improvement in reader diagnostic confidence in 174 patients (39%). Diagnostic sensitivity was higher with the core protocol plus mapping compared with the core protocol alone for myocarditis (89% [31 of 35 patients] vs 69% [24 of 35]; P = .008), Fabry disease (93% [13 of 14 patients] vs 50% [seven of 14]; P = .01), and amyloidosis (100% [16 of 16 patients] vs 63% [10 of 16]; P = .01). In the subset evaluated for downstream imaging utilization (n = 903), 47% of patients with mapping had at least one subsequent cardiac imaging test compared with 55% of patients without mapping (P = .01). Conclusion In patients with suspected cardiomyopathy, cardiac MRI with T1 and T2 mapping had high diagnostic utility and was associated with lower downstream cardiac imaging utilization. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Jerosch-Herold and Coelho-Filho in this issue.

Visual Ordinal Scoring of Coronary Artery Calcium on Contrast-Enhanced and Noncontrast Chest CT: A Retrospective Study of Diagnostic Performance and Prognostic Utility.

BACKGROUND. Current guidelines recommend visual evaluation of coronary artery calcium (CAC) on all nongated noncontrast chest CT examinations. However, chest CT examinations are often performed with contrast material administration. OBJECTIVE. The purpose of our study was to evaluate diagnostic performance, prognostic utility, and interobserver agreement of visual CAC assessment on chest CT performed for other indications. METHODS. This retrospective study included 260 patients (158 men, 102 women; mean age, 60 ± 11 [SD] years) who underwent both nongated chest CT (contrast-enhanced in 116 patients; noncontrast in 144 patients) and cardiac calcium score CT within a 12-month interval. A cardiothoracic radiologist visually assessed CAC on chest CT using an ordinal scale (absent, mild, moderate, or severe). Cardiac CT Agatston calcium scores were quantified according to established guidelines and were categorized as CAC absent (0), mild CAC (1-99), moderate CAC (100-299), or severe CAC (≥ 300). The diagnostic performance of chest CT for the presence of CAC was assessed using cardiac CT as the reference standard. Major adverse cardiac events (MACE) were assessed as a composite of cardiovascular death and myocardial infarction and were evaluated using Cox proportional hazards models. A second cardiothoracic radiologist performed visual CAC assessments in a random subset of 50 chest CT examinations to assess interob-server agreement. RESULTS. For the presence of any CAC on cardiac CT, contrast-enhanced and non-contrast chest CT had sensitivity of 83% (62/75) and 89% (85/95) (p = .20) and specificity of 100% (41/41) and 100% (49/49) (p = .99). CAC present on cardiac CT was misclassified as absent on 13 contrast-enhanced and 10 noncontrast chest CT examinations; Agatston score was less than 30 in all such patients, and none experienced any MACE. The visual ordinal CAC score was associated with MACE for contrast-enhanced chest CT (hazard ratio [HR] = 4.5 [95% CI, 1.2-16.4], p = .02) and noncontrast chest CT (HR = 3.4 [95% CI, 1.5-7.8], p = .003). Interobserver agreement was excellent for contrast-enhanced (κ = 0.89) and noncontrast (κ = 0.95) chest CT. CONCLUSION. Visual ordinal CAC assessment on both contrast-enhanced and non-contrast chest CT has high diagnostic performance, prognostic utility, and interobserver agreement. CLINICAL IMPACT. Routine reporting of CAC on all chest CT examinations regardless of clinical indication and contrast material administration could identify a large number of patients with previously unknown CAC who might benefit from preventive treatment.

Myocardial Injury Pattern at MRI in COVID-19 Vaccine-Associated Myocarditis.

Background There are limited data on the pattern and severity of myocardial injury in patients with COVID-19 vaccination-associated myocarditis. Purpose To describe myocardial injury following COVID-19 vaccination and to compare these findings to other causes of myocarditis. Materials and Methods In this retrospective cohort study, consecutive adult patients with myocarditis with at least one T1-based and at least one T2-based abnormality at cardiac MRI performed at a tertiary referral hospital from December 2019 to November 2021 were included. Patients were classified into one of three groups: myocarditis following COVID-19 vaccination, myocarditis following COVID-19 illness, and other myocarditis not associated with COVID-19 vaccination or illness. Results Of the 92 included patients, 21 (23%) had myocarditis following COVID-19 vaccination (mean age, 31 years ± 14 [SD]; 17 men; messenger RNA-1273 in 12 [57%] and BNT162b2 in nine [43%]). Ten of 92 (11%) patients had myocarditis following COVID-19 illness (mean age, 51 years ± 14; three men) and 61 of 92 (66%) patients had other myocarditis (mean age, 44 years ± 18; 36 men). MRI findings in the 21 patients with vaccine-associated myocarditis included late gadolinium enhancement (LGE) in 17 patients (81%) and left ventricular dysfunction in six (29%). Compared with other causes of myocarditis, patients with vaccine-associated myocarditis had a higher left ventricular ejection fraction and less extensive LGE, even after controlling for age, sex, and time from symptom onset to MRI. The most frequent location of LGE in all groups was subepicardial at the basal inferolateral wall, although septal involvement was less common in vaccine-associated myocarditis. At short-term follow-up (median, 22 days [IQR, 7-48 days]), all patients with vaccine-associated myocarditis were asymptomatic with no adverse events. Conclusion Cardiac MRI demonstrated a similar pattern of myocardial injury in vaccine-associated myocarditis compared with other causes, although abnormalities were less severe, with less frequent septal involvement and no adverse events over the short-term follow-up. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Raman and Neubauer in this issue.

Chronic lung allograft dysfunction phenotype and prognosis by machine learning CT analysis.

BACKGROUND: Chronic lung allograft dysfunction (CLAD) is the principal cause of graft failure in lung transplant recipients and prognosis depends on CLAD phenotype. We used a machine learning computed tomography (CT) lung texture analysis tool at CLAD diagnosis for phenotyping and prognostication compared with radiologist scoring. METHODS: This retrospective study included all adult first double lung transplant patients (January 2010-December 2015) with CLAD (censored December 2019) and inspiratory CT near CLAD diagnosis. The machine learning tool quantified ground-glass opacity, reticulation, hyperlucent lung and pulmonary vessel volume (PVV). Two radiologists scored for ground-glass opacity, reticulation, consolidation, pleural effusion, air trapping and bronchiectasis. Receiver operating characteristic curve analysis was used to evaluate the diagnostic performance of machine learning and radiologist for CLAD phenotype. Multivariable Cox proportional hazards regression analysis for allograft survival controlled for age, sex, native lung disease, cytomegalovirus serostatus and CLAD phenotype. RESULTS: 88 patients were included (57 bronchiolitis obliterans syndrome (BOS), 20 restrictive allograft syndrome (RAS)/mixed and 11 unclassified/undefined) with CT a median 9.5 days from CLAD onset. Radiologist and machine learning parameters phenotyped RAS/mixed with PVV as the strongest indicator (area under the curve (AUC) 0.85). Machine learning hyperlucent lung phenotyped BOS using only inspiratory CT (AUC 0.76). Radiologist and machine learning parameters predicted graft failure in the multivariable analysis, best with PVV (hazard ratio 1.23, 95% CI 1.05-1.44; p=0.01). CONCLUSIONS: Machine learning discriminated between CLAD phenotypes on CT. Both radiologist and machine learning scoring were associated with graft failure, independent of CLAD phenotype. PVV, unique to machine learning, was the strongest in phenotyping and prognostication.