Suyon Chang

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.

Structural properties of ZnSe on GaAs grown by atomic layer epitaxy

ZnSe epilayers were grown on GaAs (100) substrates by atomic layer epitaxy modified from chemical‐vapor deposition with thicknesses ranging from 600 to 6000 A. X‐ray‐diffraction and micro‐Raman scattering measurements were carried out to study the effects of strain in the ZnSe epilayers with different thicknesses. The increase in full width at half‐maximum of double‐crystal x‐ray rocking curves was observed for layers thicker than the critical thickness, which indicates that the crystallinity gets strongly degraded when the layers are grown over the critical thickness. The critical thickness estimated by x‐ray rocking curves is 1500 A, while that obtained by micro‐Raman scattering is 1000 A. This difference suggests that the elastic strain depends on the layer depth for ZnSe epilayers around the critical thickness.

Inferior mesenteric artery collaterals to the uterus during uterine artery embolization: Prevalence, risk factors, and clinical outcomes

PURPOSE To evaluate the prevalence of inferior mesenteric artery (IMA) collaterals to the uterus found during uterine artery embolization (UAE), associated risk factors, and clinical outcomes. MATERIALS AND METHODS The records of 559 women who underwent UAE during the period 2008-2011 for uterine fibroids or adenomyosis found on magnetic resonance imaging were retrospectively analyzed. If IMA collaterals to the uterus were suspected on aortography performed after embolization, selective angiography was performed. Risk factors for IMA collaterals to the uterus were analyzed, including the presence of adenomyosis, baseline uterine volume, or prior pelvic surgery. RESULTS Collaterals to the uterus were found from the ovarian artery (n = 21; 3.8%), IMA (n = 7; 1.3%), round ligament artery (n = 1; 0.2%), and internal pudendal artery (n = 1; 0.2%). IMA collaterals were found in seven patients. Of 185 patients, 6 (3.2%) had adenomyosis, with or without fibroids, which was significantly more frequent than the 1 (0.27%) of 374 patients who had fibroids only (P = .006). On multiple logistic regression analysis, the presence of adenomyosis (odds ratio, 19.556; P = .0168) and uterine volume (odds ratio, 1.003; P = .0069) were independent factors for the presence of IMA collaterals. Of the seven patients with IMA collaterals, embolization was not attempted in six, resulting in clinical failure in four. One patient who underwent IMA embolization with coils experienced clinical improvement. CONCLUSIONS The IMA was the second most common (1.3%) source of collaterals to the uterus. IMA collaterals were more frequent in patients with adenomyosis than in patients with fibroids only, resulting in high frequency of treatment failure.

Added value of cardiac computed tomography for evaluation of mechanical aortic valve: Emphasis on evaluation of pannus with surgical findings as standard reference

BACKGROUND The added value of cardiac computed tomography (CT) with transesophageal echocardiography (TEE) for evaluating mechanical aortic valve (AV) dysfunction has not yet been investigated. The purposes of this study were to investigate the added value of cardiac CT for evaluation of mechanical AVs and diagnoses of pannus compared to TEE, with surgical findings of redo-aortic valve replacement (AVR) used as a standard reference. METHODS 25 patients who underwent redo-AVR due to mechanical AV dysfunction and cardiac CT before redo-AVR were included. The presence of pannus, encroachment ratio by pannus, and limitation of motion (LOM) were evaluated on CT. The diagnostic performance of pannus detection was compared using TEE, CT, and CT+TEE, with surgical findings as a standard reference. The added value of CT for diagnosing the cause of mechanical AV dysfunction was assessed compared to TTE+TEE. RESULTS In two patients, CT analysis was not feasible due to severe metallic artifacts. On CT, pannus and LOM were found in 100% (23/23) and 60.9% (14/23). TEE identified pannus in 48.0% of patients (12/25). CT, TEE, and CT+TEE correctly identified pannus with sensitivity of 92.0%, 48.0%, and 92.0%, respectively (P=0.002 for CT vs. TEE). In 11 of 13 cases (84.6%) with inconclusive or negative TEE results for pannus, CT detected the pannus. Among 13 inconclusive cases of TTE+TEE for the cause of mechanical AV dysfunction, CT suggested 6 prosthetic valve obstruction (PVO) by pannus, 4 low-flow low-gradient PVO, and one LOM without significant PVO. CONCLUSIONS Cardiac CT showed added diagnostic value with TEE in the detection of pannus as the cause of mechanical AV dysfunction.

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.

Usefulness of thin‐section single‐shot turbo spin echo with half‐fourier acquisition in evaluation of local invasion of lung cancer

To evaluate the usefulness of thin‐section single‐shot turbo spin echo with half‐Fourier acquisition (SS‐TSE‐HF) alone for evaluation of local invasion of lung cancer.

Uterine Artery Embolization for Symptomatic Fibroids with High Signal Intensity on T2-Weighted MR Imaging

Objective To evaluate the effectiveness of uterine artery embolization (UAE) for treating symptomatic fibroids with high signal intensity (SI) on magnetic resonance (MR) T2-weighted imaging (T2WI). Materials and Methods A total of 537 cases, consisting of 14 patients with high SI fibroids on T2WI (T2 high group), were retrospectively included and compared with 28 randomly selected patients with low SI fibroids on T2WI (control group). High SI of a predominant fibroid on T2WI was defined as having the same or higher SI than the myometrium. Patient ages ranged from 28 to 52 years (mean, 38.1 years). All patients underwent MRI before and after UAE. Predominant fibroid and uterine volumes were calculated with MR images. Symptom status in terms of menorrhagia and dysmenorrhea was scored on a scale of 0-10, with 0 being no symptoms and 10 being the baseline, or initial symptoms. Results Of the patients in the T2 high group, 13 out of 14 (92.9%) patients demonstrated complete necrosis of the predominant fibroids. The mean volume reduction rates of the predominant fibroids in the T2 high group was 61.7% at three months after UAE, which was significantly higher than the volume reduction rates of 42.1% noted in the control group (p < 0.05). Changes in symptom scores for menorrhagia and dysmenorrhea after UAE (baseline score minus follow-up score) were 4.9 and 7.5 in T2 high group and they were 5.0 and 7.7 in control group, suggesting a significant resolution of symptoms (p < 0.01) in both groups but no significant difference between the two groups. Conclusion UAE is effective for uttering fibroids showing high SI on T2WI. The mean volume reduction rate of the predominant fibroids three months after UAE was greater in the T2 high group than in the control group.

Comparison of Cardiac Computed Tomography With Transesophageal Echocardiography for Identifying Vegetation and Intracardiac Complications in Patients With Infective Endocarditis in the Era of 3-Dimensional ImagesCLINICAL PERSPECTIVE

Background— Recent evolution of cardiac computed tomography (CT) provides useful information about valvular and perivalvular structures. We compared the diagnostic performance of CT and transesophageal echocardiography (TEE) with applications of 3-dimensional reconstruction in detecting vegetation and intracardiac complications in patients with infective endocarditis (IE). Methods and Results— Seventy-five patients (53 men; age, 58±15 years) with definite IE who underwent TEE and CT with 3-dimensional reconstruction within 3 days were analyzed. The diagnostic performances of the 2 modalities for vegetation and IE-related intracardiac complications (valve perforation, valve aneurysm, perivalvular abscess, pseudoaneurysm, fistula, and prosthetic valve dehiscence) were compared. The detection rate of vegetation in TEE and CT was 97.3% and 72.0%, respectively. The maximum sizes of vegetation identified by TEE and CT were well correlated (r=0.593; P<0.001), especially in patients with large vegetation (≥10 mm), suggestive of a high risk of systemic embolism (r=0.608; P<0.001). However, small vegetation (<10 mm) was underdiagnosed by CT (52.8%) compared with TEE (94.4%), and the sizes of the 2 modalities were poorly correlated (r=0.187; P=0.445). Both modalities showed fair diagnostic performance for detecting IE-related intracardiac complications with excellent agreement. TEE was more useful for diagnosing valve perforation and intracardiac fistula, whereas CT was better for diagnosing perivalvular abscess. Conclusions— Cardiac CT shows a comparable diagnostic performance with TEE for large vegetation and several IE-related complications. TEE is better for detecting small vegetation, valve perforation, and intracardiac fistula, whereas CT is more useful for detecting perivalvular abscess and coronary artery disease.

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.

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.