The image quality and diagnostic accuracy of T1-mapping-based synthetic late gadolinium enhancement imaging: comparison with conventional late gadolinium enhancement imaging in real-life clinical situation.

BACKGROUNDS: Synthetic late gadolinium enhancement (LGE) images are less sensitive to inversion time (TI) and robust to motion artifact, because it is generated retrospectively by post-contrast T1-mapping images. To explore the clinical applicability of synthetic LGE, we investigated the image quality and diagnostic accuracy of synthetic LGE images, in comparison to that of conventional LGE for various disease groups. METHOD AND MATERIALS: From July to November 2019, a total of 98 patients who underwent cardiovascular magnetic resonance imaging (CMR), including LGE and T1-mapping sequences, with suspicion of myocardial abnormality were retrospectively included. Synthetic magnitude inversion-recovery (IR) and phase-sensitive IR (PSIR) images were generated through calculations based on the post-contrast T1-mapping sequence. Three cardiothoracic radiologists independently analyzed the image quality of conventional and synthetic LGE images on an ordinal scale with per-segment basis and the image qualities were compared with chi-square test. The agreement of LGE detection was analyzed on per-patient and per-segment basis with Cohen's kappa test. In addition, the LGE area and percentage were semi-quantitatively analyzed for LGE positive ischemic (n = 14) and hypertrophic cardiomyopathy (n = 13) subgroups by two cardiothoracic radiologists. The difference of quantified LGE area and percentage between conventional and synthetic LGE images were assessed with Mann-Whitney U-test and the inter-reader agreement was assessed with Bland-Altman analysis. RESULTS: The image quality of synthetic images was significantly better than conventional images in both magnitude IR and PSIR through all three observers (P < 0.001, all). The agreements of per-patient and per-segment LGE detection rates were excellent (kappa = 0.815-0.864). The semi-quantitative analysis showed no significant difference in the LGE area and percentage between conventional and synthetic LGE images. In the inter-reader agreement showed only small systematic differences in both magnitude IR and PSIR and synthetic LGE images showed smaller systematic biases compared to conventional LGE images. CONCLUSION: Compared to conventional LGE images, synthetic LGE images have better image quality in real-life clinical situation.

Synthetic Extracellular Volume Fraction Derived Using Virtual Unenhanced Attenuation of Blood on Contrast-Enhanced Cardiac Dual-Energy CT in Nonischemic Cardiomyopathy.

BACKGROUND. Current methods for calculating the myocardial extracellular volume (ECV) fraction require blood sampling to determine the serum hematocrit. Synthetic hematocrit and thus synthetic ECV may be derived using unenhanced attenuation of blood. By use of virtual unenhanced (VUE) attenuation of blood, contrast-enhanced dual-energy CT (DECT) may allow synthetic ECV calculations without unenhanced acquisition. OBJECTIVE. The purpose of this study was to compare synthetic ECV calculated using synthetic hematocrit derived from VUE images and conventional ECV calculated using serum hematocrit, both of which were obtained by contrast-enhanced DECT, with ECV derived from MRI used as the reference standard. METHODS. This retrospective study included 51 patients (26 men and 25 women; mean age, 59.9 ± 15.6 [SD] years) with nonischemic cardiomyopathy who, as part of an earlier prospective investigation, underwent equilibrium phase contrast-enhanced cardiac DECT and cardiac MRI and had serum hematocrit measured within 6 hours of both tests. A separate retrospective sample of 198 patients who underwent contrast-enhanced thoracic DECT performed on the same day for suspected pulmonary embolism and serum hematocrit measurement was identified to derive a synthetic hematocrit formula using VUE attenuation of blood by linear regression analysis. In the primary sample, two radiologists independently used DECT iodine maps to obtain the conventional ECV using serum hematocrit and the synthetic ECV using synthetic hematocrit based on the independently derived formula. The concordance correlation coefficient (CCC) was computed between conventional ECV and synthetic ECV from DECT. Conventional ECV and synthetic ECV from DECT were compared with the ECV derived from MRI in Bland-Altman analyses. RESULTS. In the independent sample, the linear regression formula for synthetic hematocrit was as follows: synthetic hematocrit = 0.85 × (VUE attenuation of blood) - 5.40. In the primary sample, the conventional ECV and synthetic ECV from DECT showed excellent agreement (CCC, 0.95). Bland-Altman analysis showed a small bias of -0.44% (95% limits of agreement, -5.10% to 4.22%) between MRI-derived ECV and conventional ECV from DECT as well as a small bias of -0.78% (95% limits of agreement, -5.25% to 3.69%) between MRI-derived ECV and synthetic ECV from DECT. CONCLUSION. Synthetic ECV and conventional ECV derived from DECT show excel lent agreement and a comparable association with ECV derived from cardiac MRI. CLINICAL IMPACT. Synthetic hematocrit from VUE attenuation of blood may allow myocardial tissue characterization on DECT without the inconvenience of blood sampling.

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.

Serial T1 mapping of right ventricle in pulmonary hypertension: comparison with histology in an animal study.

BACKGROUND: Right ventricular (RV) free wall fibrosis is an important component of adverse remodeling with RV dysfunction in pulmonary hypertension (PH). However, no previous reports have compared cardiovascular magnetic resonance (CMR) findings and histological analysis for RV free wall fibrosis in PH. We aimed to assess the feasibility of CMR T1 mapping with extracellular volume fraction (ECV) for evaluating the progression of RV free wall fibrosis in PH, and compared imaging findings to histological collagen density through an animal study. METHODS: Among 42 6-week-old Wistar male rats, 30 were classified according to disease duration (baseline before monocrotaline injection, and 2, 4, 6 and 8 weeks after injection) and 12 were used to control for aging (4 and 8 weeks after the baseline). We obtained pre and post-contrast T1 maps for native T1 and ECV of RV and left ventricular (LV) free wall for six animals in each disease-duration group. Collagen density of RV free wall was calculated with Masson's trichrome staining. The Kruskall-Wallis test was performed to compare the groups. Native T1 and ECV to collagen density were analyzed with Spearman's correlation. RESULTS: The mean values of native T1, ECV and collagen density of the RV free wall at baseline were 1541 ± 33 ms, 17.2 ± 1.3%, and 4.7 ± 0.5%, respectively. The values of RV free wall did not differ according to aging (P = 0.244, 0.504 and 0.331, respectively). However, the values significantly increased according to disease duration (P < 0.001 for all). Significant correlations were observed between native T1 and collagen density (r = 0.770, P < 0.001), and between ECV and collagen density for the RV free wall (r = 0.815, P < 0.001) in PH. However, there was no significant difference in native T1 and ECV values for the LV free wall according to the disease duration from the baseline (P = 0.349 and 0.240, respectively). CONCLUSIONS: We observed significantly increased values for native T1 and ECV of the RV free wall without significant increase of the LV free wall according to the disease duration of PH, and findings were well correlated with histological collagen density.

Usefulness of cardiac magnetic resonance images for prediction of sudden cardiac arrest in patients with mitral valve prolapse: a multicenter retrospective cohort study.

BACKGROUND: An association has been identified between mitral valve prolapse (MVP) and sudden cardiac arrest (SCA), and ventricular arrhythmias (VA). This study aimed to elucidate predictive factors for SCA or VA in MVP patients. METHODS: MVP patients who underwent cardiac magnetic resonance (CMR) were retrospectively included. Patients with other structural heart disease or causes of aborted SCA were excluded. Clinical characteristics (sex, age, body mass index, histories of diabetes, hypertension, and dyslipidemia) and electrocardiographic (PR interval, QRS duration, corrected QT interval, inverted T wave in the inferior leads, bundle branch block, and atrial fibrillation), echocardiographic [mitral regurgitation grade, prolapsing mitral leaflet, and right ventricular systolic pressure (RVSP)], and CMR [left atrial volume index, both ventricular ejection fractions, both ventricular end-diastolic and systolic volume indexes, prolapse distance, mitral annular disjunction, systolic curling motion, presence of late gadolinium enhancement (LGE), LGE volume and proportion] parameters were analyzed. RESULTS: Of the 85 patients [age, 54.0 (41.0-65.0) years; 46 men], seven experienced SCA or VA. Younger age and wide QRS complex were observed more often in the SCA/VA group than in the no-SCA/VA group. The SCA/VA group exhibited lower RVSP, more systolic curling motion and LGE, greater LGE volume, and higher LGE proportion. The presence of LGE [hazard ratio (HR), 19.8; 95% confidence interval (CI) 2.65-148.15; P = 0.004], LGE volume (HR 1.08; 95% CI 1.02-1.14; P = 0.006) and LGE proportion (HR 1.32; 95% CI 1.08-1.60; P = 0.006) were independently associated with higher risk of SCA or VA in MVP patients together with systolic curling motion in each model. CONCLUSIONS: The presence of systolic curling motion, high LGE volume and proportion, and the presence of LGE on CMR were independent predictive factors for SCA or VA in MVP patients.

Prognostic Value of Coronary Artery Disease-Reporting and Data System Score for Major Adverse Cardiac Events in Patients Attending the Emergency Department With Acute Chest Pain.

OBJECTIVE: This study aimed to compare the prognostic performance of Coronary Artery Disease (CAD)-Reporting and Data System (CAD-RADS) score with those of clinical risk factors and the extent of CAD classification for predicting major adverse cardiac events in emergency department patients. METHODS: A total of 779 patients with acute chest pain at low to intermediate risk for CAD underwent cardiac computed tomography angiography. The primary end point was early and late major adverse cardiac events. We developed the following models: model 1, clinical risk factors; model 2, clinical risk factors and CAD-RADS scores; model 3, clinical risk factors and extent of CAD. RESULTS: The C-statistics revealed that both CAD-RADS score and CAD extent improved risk stratification over the clinical risk factors (C-index for early events: C-index: 0.901 vs 0.814 and 0.911 vs 0.814; C-index for late events: 0.897 vs 0.808 and 0.905 vs 0.808; all P < 0.05). CONCLUSIONS: The CAD-RADS score had additional risk prediction benefits over clinical risk factors for emergency department patients.

Differential Angiogenic Potential of 3-Dimension Spheroid of HNSCC Cells in Mouse Xenograft.

The experimental animal model is still essential in the development of new anticancer drugs. We characterized mouse tumors derived from two-dimensional (2D) monolayer cells or three-dimensional (3D) spheroids to establish an in vivo model with highly standardized conditions. Primary cancer-associated fibroblasts (CAFs) were cultured from head and neck squamous cell carcinoma (HNSCC) tumor tissues and co-injected with monolayer cancer cells or spheroids into the oral mucosa of mice. Mice tumor blood vessels were stained, followed by tissue clearing and 3D Lightsheet fluorescent imaging. We compared the effect of exosomes secreted from 2D or 3D culture conditions on the angiogenesis-related genes in HNSCC cells. Our results showed that both the cells and spheroids co-injected with primary CAFs formed tumors. Interestingly, vasculature was abundantly distributed inside the spheroid-derived but not the monolayer-derived mice tumors. In addition, cisplatin injection more significantly decreased spheroid-derived but not monolayer-derived tumor size in mice. Additionally, exosomes isolated from co-culture media of FaDu spheroid and CAF upregulated angiogenesis-related genes in HNSCC cells as compared to exosomes from FaDu cell and CAF co-culture media under in vitro conditions. The mouse tumor xenograft model derived from 3D spheroids of HNSCC cells with primary CAFs is expected to produce reliable chemotherapy drug screening results given the robust angiogenesis and lack of necrosis inside tumor tissues.

Cardiotoxicity evaluation using magnetic resonance imaging in breast Cancer patients (CareBest): study protocol for a prospective trial.

BACKGROUND: Cardiovascular disease is second only to cancer recurrence as a determinant of lifespan in cancer survivors, and cancer therapy-related cardiac dysfunction is a clinically important risk factor. We aim to investigate the use of cardiac magnetic resonance imaging (MRI) to evaluate early tissue changes and perform functional assessment of chemo- and radiation-induced cardiotoxicity and to identify MRI prognostic indicators of cardiotoxicity in breast cancer patients. METHODS: A 3-min cardiac imaging protocol will be added to the breast MRI examination to diagnose cardiotoxicity in breast cancer patients. Standardized MRI-based evaluation of breast cancer and the left ventricular myocardium will be performed at baseline and at 3, 6, and 12 months and 2 years or more after cancer treatment. We will analyze both ventricular volume and ejection fraction (EF), strain of left ventricle (LV), native T1, extracellular volume fraction (ECV), and T2 values acquired in the mid LV. DISCUSSION: The primary result of this study will be the comparison of the prognostic value of MRI parameters (native T1, ECV, both ventricular systolic function and LV strain) for cardiotoxicity. The endpoint is defined as the occurrence of a major adverse cardiac event (MACE). The secondary outcome will be an assessment of the temporal relationships between contractile dysfunction and microstructural injury over 4 years using MRI. This study will assess the usefulness of quantitative MRI to diagnose cardiotoxicity and will clarify the temporal relationships between contractile dysfunction and microstructural injury of the LV myocardium using MRI during breast cancer treatment. TRIAL REGISTRATION: The protocol was registered at clinicaltrials.gov (Clinical trial no. NCT03301389) on October 4, 2017.

Intradermal Testing With Radiocontrast Media to Prevent Recurrent Adverse Reactions.

OBJECTIVE. Adverse drug reactions (ADRs) to radiocontrast media are a significant social and economic burden and are difficult to predict. Because some ADRs to radiocontrast media may be immunologically induced, a skin test with diluted 1:10 radiocontrast media has been used to predict ADRs. However, using this test in clinical practice is difficult because of its low sensitivity. SUBJECTS AND METHODS. This study enrolled 36 patients with a history of immediate ADR to radiocontrast media who visited the Allergy and Asthma Clinic of Severance Hospital from 2017 to 2018. Patients underwent intradermal testing (IDT) with five types of diluted (1:10) and undiluted radiocontrast media (iohexol, iobitridol, iopamidol, iopromide, and iodixanol). The IDT result was regarded as positive if at least one radiocontrast medium elicited a positive reaction. Positivity of IDT and sensitivity to the culprit radiocontrast medium were calculated and compared. For subsequent CT examinations with a radiocontrast medium, the contrast agent eliciting a negative skin reaction in IDT was selected, excluding the previous culprit radiocontrast medium. RESULTS. IDT positivity and sensitivity for the culprit radiocontrast medium at 1:10 dilution were 47.2% and 47.2%, respectively, whereas the positivity and sensitivity for the undiluted radiocontrast medium were 86.1% and 75.0%, respectively. The positivity and sensitivity were higher with frequent radiocontrast medium use or with severe reaction. Of 22 patients who underwent another CT examination with the contrast medium selected on the basis of IDT results, 21 (95.5%) did not experience an ADR. CONCLUSION. IDT to prevent ADR should be performed with undiluted radiocontrast medium. Selecting an alternative radiocontrast agent on the basis of IDT results can be clinically useful to prevent recurrent ADRs to radiocontrast media.

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.

Myocardial Extracellular Volume Fraction and Change in Hematocrit Level: MR Evaluation by Using T1 Mapping in an Experimental Model of Anemia.

Purpose To evaluate the effect of changes in hematocrit level on myocardial extracellular volume (ECV) fraction, as quantified with cardiac magnetic resonance (MR) imaging in an animal model. Materials and Methods Thirteen adult male Sprague-Dawley rats underwent cardiac MR imaging before and after induction of anemia. MR imaging procedures, including unenhanced and contrast material-enhanced T1 mapping, were performed by using a saturation recovery Look-Locker sequence with a 9.4-T unit. An optimized T1 mapping sequence was established in the phantom study. Systolic function of the left ventricle (LV) was calculated from the cine images. Native and postcontrast T1 values of the LV myocardium at the midcavity level and LV blood pool, partition coefficients, and ECV were calculated. Histopathologic examination of the heart was performed after sacrifice. Intergroup comparison of variables was performed with the paired t test. Results The postanemia models exhibited lower hematocrit levels, postcontrast T1 values of the LV pool, and partition coefficients (mean, 45.7% ± 5.2 [standard deviation]; 563.8 msec ± 155.7; and 29.2 ± 3.5, respectively) than did the preanemia models (mean, 59.0% ± 4.1; 690.2 msec ± 109.7; and 38.2 ± 4.4, respectively) (P < .05 for all comparisons). There were no differences between the pre- and postanemia groups in terms of LV ejection fraction (mean, 72.7% ± 2.1 vs 73.2% ± 4.7; P = .78) and ECV (mean, 15.5% ± 2.0 vs 16.0% ± 1.9; P = .24). Conclusion Myocardial ECV measured with contrast-enhanced T1 mapping cardiac MR imaging did not significantly change despite changes in hematocrit level in anemic rat models. Extrapolation of this finding from animal models to human subjects suggests that ECV measured with MR imaging could be a robust parameter in anemic patients.

Accuracy of computed tomography for selecting the revascularization method based on SYNTAX score II.

OBJECTIVES: The application of SYNTAX score II based on coronary CT angiography (CCTA) for selecting further treatment options has not been studied. This study aimed to investigate the diagnostic performance of CCTA combined with SYNTAX score II for selecting the revascularization method compared with invasive coronary angiography (ICA) based on 2014 European Society of Cardiology (ESC)/European Association for Cardio-Thoracic Surgery (EACTS) guidelines. METHODS: From January-May 2011, 160 patients who underwent both CCTA and ICA within 30 interval days were included. The diagnostic performance of CCTA, CCTA plus CT-SYNTAX score I and CT-SYNTAX score II was analysed using ICA counterparts as references. RESULTS: Overall sensitivity, specificity, positive predictive value, negative predictive value and accuracy of CCTA plus CT-SYNTAX I for selecting coronary artery bypass grafting (CABG) candidates using ICA plus ICA-SYNTAX I as reference, were 70.6 %, 95.8 %, 66.7 %, 96.5 % and 93.1 %, respectively. The diagnostic performance of CCTA plus CT-SYNTAX II showed improvement with values of 83.3 %, 97.3 %, 71.4 %, 98.6 % and 96.3 %, respectively, using ICA plus ICA-SYNTAX II as reference. CONCLUSIONS: CCTA combined with CT-SYNTAX score II is an accurate method for selecting CABG surgery candidates compared with ICA-SYNTAX score II. KEY POINTS: • SYNTAX plus CCTA can be highly specific for selecting the revascularization method. • SYNTAX II was complemented by including clinical considerations to SYNTAX I. • CCTA plus CT-SYNTAX II is an accurate method for selecting CABG candidates.

Adverse Prognostic CT Findings for Patients With Advanced Lung Adenocarcinoma Receiving First-Line Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitor Therapy.

OBJECTIVE: The purpose of this study is to investigate adverse prognostic CT findings in patients with advanced-stage lung adenocarcinoma who are receiving epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) therapy as first-line therapy. MATERIALS AND METHODS: We included 199 patients (71 men and 128 women; mean ± SD age, 64.3 ± 11.2 years) with stage IIIB or IV lung adenocarcinoma who received first-line EGFR-TKI therapy between January 2009 and December 2015. Clinical findings and imaging parameters on CT images obtained before TKI therapy were analyzed, including tumor size, TNM category according to the seventh edition of the American Joint Committee on Cancer lung cancer TNM staging system, tumor type, the presence of cavity or necrosis, pleural effusion, and metastasis to pleura, lung, and distant organs. Response evaluation was performed according to the Response Evaluation Criteria in Solid Tumor version 1.1 guidelines. Correlation of clinical and radiologic findings with durations of progression-free survival (PFS) and overall survival (OS) was evaluated using a Cox proportional hazard model. RESULTS: Pleural effusion (hazard ratio [HR], 2.095; 95% CI, 1.394-3.147; p < 0.001) and an N2 or N3 tumor category (HR, 2.145; 95% CI, 1.280-3.594; p = 0.004) were significantly associated with a short PFS duration in multivariate analysis. Older age (HR, 1.040; 95% CI, 1.014-1.067; p = 0.002), an N2 or N3 tumor category (HR, 2.427; 95% CI, 1.068-5.518; p = 0.034), pleural effusion (HR, 1.903; 95% CI, 1.105-3.276; p = 0.020), and distant metastasis (HR, 2.795; 95% CI, 1.356-5.765; p = 0.005) were associated with a short OS duration in multivariate analysis. CONCLUSION: Pre-TKI therapy CT findings of pleural effusion and high N-category tumors are associated with short durations of PFS and OS in patients with lung adenocarcinoma who are receiving EGFR-TKI therapy.

Effects of bismuth breast shielding on iodine quantification in dual-energy computed tomography: an experimental phantom study.

BACKGROUND: Although the bismuth breast shield can reduce radiation exposure to the breast during dual-energy computed tomography (DECT), it can potentially affect material quantification on DECT due to artifacts. PURPOSE: To evaluate the effects of bismuth breast shielding on iodine quantification and radiation exposure in DECT. MATERIAL AND METHODS: Small balloons were made with 0.2%, 0.6% and 1.0% blended iodinated contrast (370 mg/mL of iodine) with water. The balloons were located at both anterior and posterior lungs in an adult anthropomorphic chest phantom. DECT was performed with and without breast shielding. Afterwards, iodine concentration values were measured for each balloon on the iodine maps. Absorbed radiation doses in the breast were measured with the optically stimulated luminescence dosimeter. RESULTS: After shielding, we obtained significantly decreased iodine quantification for all three concentrations with 0.78 ± 0.13 to 0.46 ± 0.13 mg/mL, 2.31 ± 0.17 to 1.68 ± 0.19 mg/mL, and 3.82 ± 0.10 to 2.84 ± 0.20 mg/mL at the anterior location, and 0.72 ± 0.11 to 0.48 ± 0.09 mg/mL, 2.24 ± 0.13 to 1.87 ± 0.21 mg/mL, and 3.75 ± 0.16 to 3.15 ± 0.14 mg/mL at the posterior location for the 0.2%, 0.6%, and 1.0% balloons, respectively ( P = 0.001 for all). After shielding, absorbed radiation doses to the breast significantly decreased by 14.8% (4.32 ± 0.33 to 3.68 ± 0.30 mGy; P = 0.005). CONCLUSION: Although using the bismuth breast shield may decrease radiation exposure to the breast on DECT, it may also significantly affect iodine quantification.

Contrast-enhanced T1 mapping-based extracellular volume fraction independently predicts clinical outcome in patients with non-ischemic dilated cardiomyopathy: a prospective cohort study.

OBJECTIVES: We aimed to evaluate the prognostic role of cardiac magnetic resonance imaging (CMR)-based extracellular volume fraction (ECV) in patients with non-ischemic dilated cardiomyopathy (NIDCM) and compare it with late gadolinium enhancement (LGE) parameters. METHODS: This was a single-center, prospective, cohort study of 117 NIDCM patients (71 men, 51.9 ± 16.7 years) who underwent clinical 3.0-T CMR. Myocardial ECV and LGE were quantified on the left ventricular myocardium. The presence of midwall LGE was also detected. Nineteen healthy subjects served as controls. The primary end points were cardiovascular (CV) events defined by CV death, rehospitalization due to heart failure, and heart transplantation. RESULTS: During the follow-up period (median duration, 11.2 months; 25th-75th percentile, 7.8-21.9 months), the primary end points occurred in 19 patients (16.2%). The ECV (per 3% and 1% increase) was associated with a hazard ratio of 1.80 and 1.22 (95% confidence interval [CI], 1.48-2.20 and 1.14-1.30, respectively; p < 0.001) for the CV events. Multivariable analysis also indicated that ECV was an independent prognostic factor and had a higher prognostic value (Harrell's c statistic, 0.88) than LGE quantification values (0.77) or midwall LGE (0.80). CONCLUSION: CMR-based ECV independently predicts the clinical outcome in NIDCM patients. KEY POINTS: • T1-mapping-based ECV is a useful parameter of risk stratification in NIDCM • ECV has a higher prognostic value than LGE • Contrast-enhanced T1-mapping CMR is a feasible and safe method.

Volume-based quantification using dual-energy computed tomography in the differentiation of thymic epithelial tumours: an initial experience.

OBJECTIVES: To investigate the diagnostic value of dual-energy computed tomography (DECT) in differentiating between low- and high-risk thymomas and thymic carcinomas. MATERIALS: Our institutional review board approved this study, and patients provided informed consent. We prospectively enrolled 37 patients (20 males, mean age: 55.6 years) with thymic epithelial tumour. All patients underwent DECT. For quantitative analysis, two reviewers measured the following tumour parameters: CT attenuation value in contrast Hounsfield units (CHU), iodine-related HU and iodine concentration (mg/ml). Pathological results confirmed the final diagnosis. RESULTS: Of the 37 thymic tumours, 23 (62.2 %) were low-risk thymomas, five (13.5 %) were high-risk thymomas and nine (24.3 %) were thymic carcinomas. According to quantitative analysis, iodine-related HU and iodine concentration were significantly different among low-risk thymomas, high-risk thymomas and thymic carcinomas (median: 29.78 HU vs. 14.55 HU vs. 19.95 HU, p = 0.001 and 1.92 mg/ml vs. 0.99 mg/ml vs. 1.18 mg/ml, p < 0.001, respectively). CONCLUSION: DECT using a quantitative analytical method based on iodine concentration measurement can be used to differentiate among thymic epithelial tumours using single-phase scanning. KEY POINTS: • IHU and IC were lower in high-risk thymomas/carcinomas than in low-risk thymomas • IHU and IC were lower in advanced-stage thymomas than in early-stage thymomas • Dual-energy CT helps differentiate among thymic epithelial tumours.

Absolute-Delay Multiphase Reconstruction Reduces Prosthetic Valve-Related and Atrial Fibrillation-Related Artifacts at Cardiac CT.

OBJECTIVE: The objective of our study was to compare the image quality of cardiac CT images of mechanical valves in patients with irregular heart rates (HRs) using absolute-delay multiphase reconstruction versus relative-delay multiphase reconstruction. MATERIALS AND METHODS: A total of 26 patients with 40 mechanical valves who had atrial fibrillation during CT were included. The image quality of the CT scans was assessed for the subvalvular and valvular regions on a 4-point scale. The paired t test or Wilcoxon signed rank test was used to compare image quality scores between the relative-delay and absolute-delay reconstruction techniques. The overall image quality score was determined as the mean of the valvular and subvalvular region scores. RESULTS: For valvular regions, the image quality scores were 2.93 ± 0.73 (mean ± SD) for the relative-delay reconstruction technique and 3.55 ± 0.60 for the absolute-delay reconstruction technique (p < 0.0001). For subvalvular regions, the image quality scores were 2.8 ± 2.80 ± 0.79 and 3.35 ± 0.66 for the relative- and absolute-delay reconstructions (p < 0.0001), respectively. The nondiagnostic image quality group consisted of relative-delay reconstruction images of three valves (7.5%); the image quality scores for the absolute-delay reconstruction images of all three valves were improved, and the absolute-delay reconstruction images of the three valves were of diagnostic quality (p < 0.0001). CONCLUSION: Absolute-delay multiphase reconstruction can improve CT image quality of mechanical valves in patients with an irregular HR compared with relative-delay reconstruction.

Myocardial Extracellular Volume Fraction with Dual-Energy Equilibrium Contrast-enhanced Cardiac CT in Nonischemic Cardiomyopathy: A Prospective Comparison with Cardiac MR Imaging.

Purpose To evaluate the feasibility of equilibrium contrast material-enhanced dual-energy cardiac computed tomography (CT) to determine extracellular volume fraction (ECV) in nonischemic cardiomyopathy (CMP) compared with magnetic resonance (MR) imaging. Materials and Methods This study was approved by the institutional review board; informed consent was obtained. Seven healthy subjects and 23 patients (six with hypertrophic CMP, nine with dilated CMP, four with amyloidosis, and four with sarcoidosis) (mean age ± standard deviation, 57.33 years ± 14.82; 19 male participants [63.3%]) were prospectively enrolled. Twelve minutes after contrast material injection (1.8 mL/kg at 3 mL/sec), dual-energy cardiac CT was performed. ECV was measured by two observers independently. Hematocrit levels were compared between healthy subjects and patients with the Mann-Whitney U test. In per-subject analysis, interobserver agreement for CT was assessed with the intraclass correlation coefficient (ICC), and intertest agreement between MR imaging and CT was assessed with Bland-Altman analysis. In per-segment analysis, Student t tests in the linear mixed model were used to compare ECV on CT images between healthy subjects and patients. Results Hematocrit level was 43.44% ± 1.80 for healthy subjects and 41.23% ± 5.61 for patients with MR imaging (P = .16) and 43.50% ± 1.92 for healthy subjects and 41.35% ± 5.92 for patients with CT (P = .15). For observer 1 in per-subject analysis, ECV was 34.18% ± 8.98 for MR imaging and 34.48% ± 8.97 for CT. For observer 2, myocardial ECV was 34.42% ± 9.03 for MR imaging and 33.98% ± 9.05 for CT. Interobserver agreement for ECV at CT was excellent (ICC = 0.987). Bland-Altman analysis between MR imaging and CT showed a small bias (-0.06%), with 95% limits of agreement of -1.19 and 1.79. Compared with healthy subjects, patients with hypertrophic CMP, dilated CMP, amyloidosis, and sarcoidosis had significantly higher myocardial ECV at dual-energy equilibrium contrast-enhanced cardiac CT (all P < .01) in per-segment analysis. Conclusion Myocardial ECV with dual-energy equilibrium contrast-enhanced CT showed good agreement with MR imaging findings, suggesting the potential of myocardial tissue characterization with CT. (©) RSNA, 2016.

Feasibility of Single Scan for Simultaneous Evaluation of Regional Krypton and Iodine Concentrations with Dual-Energy CT: An Experimental Study.

Purpose To evaluate the feasibility of a simultaneous single scan of regional krypton and iodine concentrations by using dual-energy computed tomography (CT). Materials and Methods The study was approved by the institutional animal experimental committee. An airway obstruction model was first made in 10 beagle dogs, and a pulmonary arterial occlusion was induced in each animal after 1 week. For each model, three sessions of dual-energy CT (80% krypton ventilation [krypton CT], 80% krypton ventilation with iodine enhancement [mixed-contrast agent CT], and iodine enhancement [iodine CT]) were performed. Krypton maps were made from krypton and mixed-contrast agent CT, and iodine maps were made from iodine and mixed-contrast agent CT. Observers measured overlay Hounsfield units of the diseased and contralateral segments on each map. Values were compared by using the Wilcoxon signed-rank test. Results In krypton maps of airway obstruction, overlay Hounsfield units of diseased segments were significantly decreased compared with those of contralateral segments in both krypton and mixed-contrast agent CT (P = .005 for both). However, the values of mixed-contrast agent CT were significantly higher than those of krypton CT for both segments (P = .005 and .007, respectively). In iodine maps of pulmonary arterial occlusion, values were significantly lower in diseased segments than in contralateral segments for both iodine and mixed-contrast agent CT (P = .005 for both), without significant difference between iodine and mixed-contrast agent CT for both segments (P = .126 and .307, respectively). Conclusion Although some limitations may exist, it might be feasible to analyze regional krypton and iodine concentrations simultaneously by using dual-energy CT. © RSNA, 2016.

Prognostic impact of cytological fluid tumor markers in non-small cell lung cancer.

The serum tumor markers CYFRA 21-1, carcinoembryonic antigen (CEA), and squamous cell carcinoma antigen (SCCA) are useful in diagnosis and prognosis of non-small cell lung cancer (NSCLC). Cytologic tumor markers obtained during needle aspiration biopsies (NAB) of lung lesions are useful for NSCLC diagnosis. This study investigated the incremental prognostic value of cytologic tumor markers compared to serum tumor markers. This prospective study included 253 patients diagnosed with NSCLC by NAB with cytologic tumor marker analysis. Levels of cytologic CYFRA 21-1, CEA, SCCA, and their serum counterparts were followed up for survival analysis. Optimal cutoff values for each tumor marker were obtained for overall survival (OS) and progression-free survival (PFS) analyses. All patients were followed up for a median of 22.8 months. Using cutoff values of 0.44 ng/ml for C-SCCA, 2.0 ng/ml for S-SCCA, and 3.3 ng/ml for S-CYFRA, a multivariate analysis revealed that high S-SCCA (hazard ratio, HR, 1.84) and high C-SCCA (HR, 1.63) were independent predictive factors of OS. The 3-year overall survival rate was 55 vs. 80 % for high and low C-SCCA, respectively. Cytologic tumor marker level detection is easily obtainable and provides prognostic information for NSCLC. Cytologic tumor markers provide comparable prognostic information relative to serum tumor markers, with C-SCCA acting as a strong prognostic factor of overall survival and PFS.