Assessment of Feasibility and Interscan Variability of Short-time Cardiac MRI for Cardiotoxicity Evaluation in Breast Cancer.

Purpose To investigate the feasibility and interscan variability of short-time cardiac MRI protocol after chemotherapy in individuals with breast cancer. Materials and Methods A total of 13 healthy female controls (mean age, 52.4 years ± 13.2 [SD]) and 85 female participants with breast cancer (mean age, 51.8 years ± 9.9) undergoing chemotherapy prospectively underwent routine breast MRI and short-time cardiac MRI using a 3-T scanner with peripheral pulse gating in the prone position. Interscan, intercoil, and interobserver reproducibility and variability of native T1 and extracellular volume (ECV), as well as ventricular functional parameters, were measured using the intraclass correlation coefficient (ICC), standard error of measurement (SEM), or coefficient of variation (CoV). Results Left ventricular functional parameters had excellent interscan reproducibility (ICC ≥ 0.80). Left ventricular ejection fraction showed low interscan variability in control and chemotherapy participants (SEM, 2.0 and 1.2; CoV, 3.1 and 1.9, respectively). Native T1 showed excellent interscan (ICC, 0.75) and intercoil (ICC, 0.81) reproducibility in the control group and good interscan reproducibility (ICC, 0.72 and 0.73, respectively) in the participants undergoing immediate and remote chemotherapy. Interscan reproducibility for ECV was excellent in the control group and in the remote chemotherapy group (ICC, 0.93 and 0.88, respectively) and fair in the immediate chemotherapy group (ICC, 0.52). In the regional analysis, interscan repeatability and variability of native T1 and ECV were superior in the anteroseptum or inferoseptum than in other segments in the immediate chemotherapy group. Native T1 and ECV had good to excellent interobserver agreement across all groups. Conclusion Short-time cardiac MRI showed excellent results for interscan, intercoil, and interobserver reproducibility and variability for ventricular functional or tissue characterization parameters, suggesting that this modality is feasible for routine surveillance of cardiotoxicity evaluation in individuals with breast cancer. Keywords: Cardiac MRI, Heart, Cardiomyopathy ClinicalTrials.gov registration no. NCT03301389 Supplemental material is available for this article. © RSNA, 2024.

Ultrahigh-field cardiovascular magnetic resonance T1 and T2 mapping for the assessment of anthracycline-induced cardiotoxicity in rat models: validation against histopathologic changes.

BACKGROUND: Chemotherapy-induced cardiotoxicity is a well-recognized adverse effect of chemotherapy. Quantitative T1-mapping cardiovascular magnetic resonance (CMR) is useful for detecting subclinical myocardial changes in anthracycline-induced cardiotoxicity. The aim of the present study was to histopathologically validate the T1 and T2 mapping parameters for the evaluation of diffuse myocardial changes in rat models of cardiotoxicity. METHODS: Rat models of cardiotoxicity were generated by injecting rats with doxorubicin (1 mg/kg, twice a week). CMR was performed with a 9.4 T ultrahigh-field scanner using cine, pre-T1, post-T1 and T2 mapping sequences to evaluate the left ventricular ejection fraction (LVEF), native T1, T2, and extracellular volume fraction (ECV). Histopathological examinations were performed and the association of histopathological changes with CMR parameters was assessed. RESULTS: Five control rats and 36 doxorubicin-treated rats were included and classified into treatment periods. In the doxorubicin-treated rats, the LVEF significantly decreased after 12 weeks of treatment (control vs. 12-week treated: 73 ± 4% vs. 59 ± 9%, P = 0.01).  Increased native T1 and ECV were observed after 6 weeks of treatment (control vs. 6-week treated: 1148 ± 58 ms, 14.3 ± 1% vs. 1320 ± 56 ms, 20.3 ± 3%; P = 0.005, < 0.05, respectively). T2 values also increased by six weeks of treatment (control vs. 6-week treated: 16.3 ± 2 ms vs. 10.3 ± 1 ms, P < 0.05). The main histopathological features were myocardial injury, interstitial fibrosis, inflammation, and edema. The mean vacuolar change (%), fibrosis (%), and inflammation score were significantly higher in 6-week treated rats than in the controls (P = 0.03, 0.03, 0.02, respectively). In the univariable analysis, vacuolar change showed the highest correlation with native T1 value (R = 0.60, P < 0.001), and fibrosis showed the highest correlation with ECV value (R = 0.78, P < 0.001). In the multiple linear regression analysis model, vacuolar change was a significant factor for change in native T1 (P = 0.01), and vacuolar change and fibrosis were significant factors for change in ECV (P = 0.006, P < 0.001, respectively) by adding other histopathological parameters (i.e., inflammation and edema scores) CONCLUSIONS: Quantitative T1 and T2 mapping CMR is a useful non-invasive tool reflecting subclinical histopathological changes in anthracycline-induced cardiotoxicity.

Utility of Dual-Energy CT-based Monochromatic Imaging in the Assessment of Myocardial Delayed Enhancement in Patients with Cardiomyopathy.

Purpose To investigate the diagnostic utility of dual-energy computed tomography (CT)-based monochromatic imaging for myocardial delayed enhancement (MDE) assessment in patients with cardiomyopathy. Materials and Methods The institutional review board approved this prospective study, and informed consent was obtained from all participants who were enrolled in the study. Forty patients (27 men and 13 women; mean age, 56 years ± 15 [standard deviation]; age range, 22-81 years) with cardiomyopathy underwent cardiac magnetic resonance (MR) imaging and dual-energy CT. Conventional (120-kV) and monochromatic (60-, 70-, and 80-keV) images were reconstructed from the dual-energy CT acquisition. Subjective quality score, contrast-to-noise ratio (CNR), and beam-hardening artifacts were compared pairwise with the Friedman test at post hoc analysis. With cardiac MR imaging as the reference standard, diagnostic performance of dual-energy CT in MDE detection and its predictive ability for pattern classification were compared pairwise by using logistic regression analysis with the generalized estimating equation in a per-segment analysis. The Bland-Altman method was used to find agreement between cardiac MR imaging and CT in MDE quantification. Results Among the monochromatic images, 70-keV CT images resulted in higher subjective quality (mean score, 3.38 ± 0.54 vs 3.15 ± 0.43; P = .0067), higher CNR (mean, 4.26 ± 1.38 vs 3.93 ± 1.33; P = .0047), and a lower value for beam-hardening artifacts (mean, 3.47 ± 1.56 vs 4.15 ± 1.67; P < .0001) when compared with conventional CT. When compared with conventional CT, 70-keV CT showed improved diagnostic performance for MDE detection (sensitivity, 94.6% vs 90.4% [P = .0032]; specificity, 96.0% vs 94.0% [P = .0031]; and accuracy, 95.6% vs 92.7% [P < .0001]) and improved predictive ability for pattern classification (subendocardial, 91.5% vs 84.3% [P = .0111]; epicardial, 94.3% vs 73.5% [P = .0001]; transmural, 93.0% vs 77.7% [P = .0018]; mesocardial, 85.4% vs 69.2% [P = .0047]; and patchy. 84.4% vs 78.4% [P = .1514]). For MDE quantification, 70-keV CT showed a small bias 0.1534% (95% limits of agreement: -4.7013, 5.0080). Conclusion Dual-energy CT-based 70-keV monochromatic images improve MDE assessment in patients with cardiomyopathy via improved image quality and CNR and reduced beam-hardening artifacts when compared with conventional CT images. © RSNA, 2017 Online supplemental material is available for this article.

Assessment of myocardial delayed enhancement with cardiac computed tomography in cardiomyopathies: a prospective comparison with delayed enhancement cardiac magnetic resonance imaging.

To evaluate the feasibility of cardiac CT for the evaluation of myocardial delayed enhancement (MDE) in the assessment of patients with cardiomyopathy, compared to cardiac MRI. A total of 37 patients (mean age 54.9 ± 15.7 years, 24 men) who underwent cardiac MRI to evaluate cardiomyopathy were enrolled. Dual-energy ECG-gated cardiac CT was acquired 12 min after contrast injection. Two observers evaluated cardiac MRI and cardiac CT at different kV settings (100, 120 and 140 kV) independently for MDE pattern-classification (patchy, transmural, subendocardial, epicardial and mesocardial), differentiation between ischemic and non-ischemic cardiomyopathy and MDE quantification (percentage MDE). Kappa statics and the intraclass correlation coefficient were used for statistical analysis. Among different kV settings, 100-kV CT showed excellent agreements compared to cardiac MRI for MDE detection (κ = 0.886 and 0.873, respectively), MDE pattern-classification (κ = 0.888 and 0.881, respectively) and differentiation between ischemic and non-ischemic cardiomyopathy (κ = 1.000 and 0.893, respectively) for both Observer 1 and Observer 2. The Bland-Altman plot between MRI and 100-kV CT for the percentage MDE showed a very small bias (-0.15%) with 95% limits of agreement of -7.02 and 6.72. Cardiac CT using 100 kV might be an alternative method to cardiac MRI in the assessment of cardiomyopathy, particularly in patients with contraindications to cardiac MRI.

Assessment of Mitral Paravalvular Leakage After Mitral Valve Replacement Using Cardiac Computed Tomography: Comparison With Surgical Findings.

BACKGROUND: The diagnostic performance of cardiac computed tomography (CT) for detection of paravalvular leakage (PVL) after mitral valve replacement has not been investigated in a large population. We aimed to investigate the diagnostic accuracy of CT for diagnosis of mitral PVL using surgical findings as the standard reference and to compare the diagnostic performance of CT with those of transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE). METHODS AND RESULTS: A total of 204 patients with previous mitral valve replacement who underwent cardiac CT were retrospectively included. The presence of mitral PVL was analyzed on CT, TTE, and TEE. In 78 patients who underwent redo-surgery, diagnostic performance for the detection of PVL for CT, TTE, and TEE were compared with surgical findings as the standard reference. The location of mitral PVL on CT and TEE was compared with surgical findings. Mitral PVL was present in 18.1% (37/204) on CT, in 16.2% (32/198) on TTE, and in 42.6% (29/68) on TEE. On the surgical field, PVL was identified in 41.0% (32/78). The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy for detection of PVL were 96.9%, 97.8%, 96.9%, 97.8%, and 97.4% for CT; 81.3%, 95.6%, 92.9%, 87.8%, and 89.6% for TTE; and 96.2%, 95.8%, 96.2%, 95.8%, and 96.0% for TEE. CT and TEE identified the correct location of PVL in 75.9% (22/29) and 85.6% (19/23). CONCLUSIONS: Cardiac CT may have better diagnostic accuracy compared with TTE for the detection of mitral PVL and may be comparable to TEE for the detection and localization of PVL.

Factors affecting computed tomography image quality for assessment of mechanical aortic valves.

Evaluating mechanical valves with computed tomography (CT) can be problematic because artifacts from the metallic components of valves can hamper image quality. The purpose of this study was to determine factors affecting the image quality of cardiac CT to improve assessment of mechanical aortic valves. A total of 144 patients who underwent aortic valve replacement with mechanical valves (ten different types) and who underwent cardiac CT were included. Using a four-point grading system, the image quality of the CT scans was assessed for visibility of the valve leaflets and the subvalvular regions. Data regarding the type of mechanical valve, tube voltage, average heart rate (HR), and HR variability during CT scanning were compared between the non-diagnostic (overall image quality score ≤2) and diagnostic (overall image quality score >2) image quality groups. Logistic regression analyses were performed to identify predictors of non-diagnostic image quality. The percentage of valve types that incorporated a cobalt-chrome component (two types in total) and HR variability were significantly higher in the non-diagnostic image group than in the diagnostic group (P < 0.001 and P = 0.013, respectively). The average HR and tube voltage were not significantly different between the two groups (P > 0.05). Valve type was the only independent predictor of non-diagnostic quality. The CT image quality for patients with mechanical aortic valves differed significantly depending on the type of mechanical valve used and on the degree of HR variability.

Assessment of mitral annuloplasty ring by cardiac computed tomography: Correlation with echocardiographic parameters and comparison between two different ring types.

OBJECTIVES: This study investigated computed tomographic (CT) appearance after mitral ring annuloplasty, especially comparing CT findings between patients with normal pressure gradient (PG) and patients with functional mitral stenosis (MS) and between 2 commonly used types of annuloplasty ring. METHODS: A total of 45 cardiac CT scans in patients who underwent mitral ring annuloplasty (Carpentier-Edwards ring, n = 27; Duran ring, n = 18) were retrospectively reviewed. On CT scan, presence of significant pannus around the annuloplasty ring, presence of leaflet thickening, and maximal mitral opening area were analyzed. CT findings were compared between patients with normal PG and patients with functional MS (mean diastolic PG ≥ 5 mm Hg). Incidences of functional MS and CT findings were compared between ring types. RESULTS: Significant pannus was present in 10 cases and leaflet thickening in 31 cases, and maximal opening area was 2.34 ± 0.717 cm(2). Valve opening area on CT was positively correlated with mitral valve area on transthoracic echocardiography and negatively correlated with mean diastolic PG. Mean diastolic PG was significantly elevated with increasing pannus severity. Patients with functional MS had more significant pannus than patients with normal PG. The Duran ring group had higher mean diastolic PG, smaller mitral valve area, and higher incidence of functional MS than the Carpentier-Edwards ring group (P < .05). The proportion of pannus and significant pannus was significantly higher in the Duran ring group (P < .05). CONCLUSIONS: Significant pannus around the annuloplasty ring on CT may cause functional MS after mitral ring annuloplasty. This may occur more frequently with the Duran ring.