Dong Hyun Yang

Association Between Bicuspid Aortic Valve Phenotype and Patterns of Valvular Dysfunction and Bicuspid Aortopathy: Comprehensive Evaluation Using MDCT and Echocardiography

OBJECTIVES We sought to define the clinical importance of an integrated classification of bicuspid aortic valve (BAV) phenotypes and aortopathy using multidetector computed tomography (MDCT). BACKGROUND An association between BAV phenotypes and the pattern of valvular dysfunction or bicuspid aortopathy has yet to be definitely established. METHODS The study cohort included 167 subjects (116 men, age 54.6 ± 14.4 years) who underwent both MDCT and transthoracic echocardiography from 2003 to 2010. Two BAV phenotypes-fusion of the right and left coronary cusps (BAV-AP) and fusion of the right or left coronary cusp and noncoronary cusp (BAV-RL)-were identified. Forty-five patients showed normal aortic dimensions and were classified as type 0. In the remaining patients, hierarchic cluster analysis showed 3 different types of bicuspid aortopathy according to the pattern of aortic dilation: type 1 (aortic enlargement confined to the sinus of Valsalva [n = 34]), type 2 (aortic enlargement involving the tubular portion of the ascending aorta [n = 49]), and type 3 (aortic enlargement extending to the transverse aortic arch [n = 39]). RESULTS The prevalence of BAV-AP and BAV-RL was 55.7% and 44.3%, respectively. Comparing BAV-AP and BAV-RL, no differences in age or in the prevalence of male sex were determined. However, significant differences in the valvular dysfunction pattern were noted, with moderate-to-severe aortic stenosis predominating in patients with BAV-RL (66.2% vs. 46.2% in BAV-AP; p = 0.01), and moderate-to-severe aortic regurgitation in BAV-AP (32.3% vs. 6.8% in BAV-RL; p < 0.0001). A normal aorta was the most common phenotype in BAV-AP patients (33.3% vs. 18.9% in BAV-RL; p = 0.037), and type 3 aortopathy was the most common phenotype in BAV-RL patients (40.5% vs. 9.7% in BAV-AP; p < 0.0001). CONCLUSIONS The patterns of valvular dysfunction and bicuspid aortopathy differed significantly between the 2 BAV phenotypes, suggesting the possibility of etiologically different entities.

Focus Issue: Frontiers in Heart Valve ImagingOriginal ResearchAssociation Between Bicuspid Aortic Valve Phenotype and Patterns of Valvular Dysfunction and Bicuspid Aortopathy: Comprehensive Evaluation Using MDCT and Echocardiography

OBJECTIVES We sought to define the clinical importance of an integrated classification of bicuspid aortic valve (BAV) phenotypes and aortopathy using multidetector computed tomography (MDCT). BACKGROUND An association between BAV phenotypes and the pattern of valvular dysfunction or bicuspid aortopathy has yet to be definitely established. METHODS The study cohort included 167 subjects (116 men, age 54.6 ± 14.4 years) who underwent both MDCT and transthoracic echocardiography from 2003 to 2010. Two BAV phenotypes-fusion of the right and left coronary cusps (BAV-AP) and fusion of the right or left coronary cusp and noncoronary cusp (BAV-RL)-were identified. Forty-five patients showed normal aortic dimensions and were classified as type 0. In the remaining patients, hierarchic cluster analysis showed 3 different types of bicuspid aortopathy according to the pattern of aortic dilation: type 1 (aortic enlargement confined to the sinus of Valsalva [n = 34]), type 2 (aortic enlargement involving the tubular portion of the ascending aorta [n = 49]), and type 3 (aortic enlargement extending to the transverse aortic arch [n = 39]). RESULTS The prevalence of BAV-AP and BAV-RL was 55.7% and 44.3%, respectively. Comparing BAV-AP and BAV-RL, no differences in age or in the prevalence of male sex were determined. However, significant differences in the valvular dysfunction pattern were noted, with moderate-to-severe aortic stenosis predominating in patients with BAV-RL (66.2% vs. 46.2% in BAV-AP; p = 0.01), and moderate-to-severe aortic regurgitation in BAV-AP (32.3% vs. 6.8% in BAV-RL; p < 0.0001). A normal aorta was the most common phenotype in BAV-AP patients (33.3% vs. 18.9% in BAV-RL; p = 0.037), and type 3 aortopathy was the most common phenotype in BAV-RL patients (40.5% vs. 9.7% in BAV-AP; p < 0.0001). CONCLUSIONS The patterns of valvular dysfunction and bicuspid aortopathy differed significantly between the 2 BAV phenotypes, suggesting the possibility of etiologically different entities.

Autoimmune pancreatitis: radiologic findings in 20 patients

BackgroundAutoimmune pancreatitis is a new clinical entity that is characterized by peculiar histopathologic and laboratory findings and by a dramatic clinical response to corticosteroid therapy. We evaluated the radiologic findings of autoimmune pancreatitis.MethodsComputed tomographic, magnetic resonance imaging, endoscopic retrograde cholangiopancreatographic, and ultrasonographic findings of 20 patients with autoimmune pancreatitis in our hospital between November 2000 and December 2003 were retrospectively reviewed regarding changes and ancillary findings in the pancreatic parenchyma, the main pancreatic duct, peripancreatic vessels, and distal common bile duct. In addition, follow-up images were reviewed for changes in any abnormality seen on the initial examinations.ResultsPancreatic parenchymal enlargement was invariably seen that was diffuse (n = 19) or focal (n = 1), with homogeneous contrast enhancement on computed tomography (n = 20) and magnetic resonance imaging (n = 15). Capsule-like rim enhancement was seen in six patients. There was focal (n = 18) or diffuse (n = 2) narrowing of the main pancreatic duct and it was usually multifocal (n = 17) in the former. Narrowing of the peripancreatic veins was seen in 14 patients. There was tapered (n = 15) or abrupt (n = 3) narrowing of the distal common bile duct in 18 patients, with contrast enhancement of the narrowed segment in eight. Invariably, changes in the pancreatic parenchyma, main pancreatic duct, peripancreatic vessels, and common bile duct were normalized on follow-up studies after steroid therapy.ConclusionIn this series, common radiologic findings of autoimmune pancreatitis were (a) diffuse pancreas enlargement, (b) multifocal narrowing of the main pancreatic duct, (c) narrowing of peripancreatic veins, and (d) tapered narrowing of the distal common bile duct with frequent contrast enhancement. These findings were usually reversible with steroid therapy.

Time‐resolved three‐dimensional contrast‐enhanced magnetic resonance angiography in patients who have undergone a Fontan operation or bidirectional cavopulmonary connection: Initial experience

To evaluate the usefulness of time‐resolved three‐dimensional (3D) magnetic resonance angiography (MRA) using diluted contrast agent (CA) in patients who had undergone a Fontan operation or bidirectional cavopulmonary connection (BCPC).

Multislice CT angiography of interrupted aortic arch

Interrupted aortic arch (IAA) is defined as complete luminal and anatomic discontinuity between the ascending and descending aorta. Because almost all patients with IAA become critically ill during the neonatal period, they should undergo urgent corrective surgery. This clinical urgency necessitates a fast and accurate noninvasive diagnostic method. Although echocardiography remains the primary imaging tool for this purpose, it is not always sufficient for planning surgical correction of IAA, principally due to a limited acoustic window and the inexperience of imagers. In this context, multislice CT angiography is regarded as an appropriate imaging technique complementary to echocardiography because it is fast, accurate, and objective for the diagnosis of IAA. In this article we describe what cardiac radiologists should know about IAA in their clinical practice, including clinicopathological features, CT features with contemporary surgical methods and postoperative complications, and differentiation from coarctation of the aorta and aortic arch atresia.

Korean Guidelines for the Appropriate Use of Cardiac CT

The development of cardiac CT has provided a non-invasive alternative to echocardiography, exercise electrocardiogram, and invasive angiography and cardiac CT continues to develop at an exponential speed even now. The appropriate use of cardiac CT may lead to improvements in the medical performances of physicians and can reduce medical costs which eventually contribute to better public health. However, until now, there has been no guideline regarding the appropriate use of cardiac CT in Korea. We intend to provide guidelines for the appropriate use of cardiac CT in heart diseases based on scientific data. The purpose of this guideline is to assist clinicians and other health professionals in the use of cardiac CT for diagnosis and treatment of heart diseases, especially in patients at high risk or suspected of heart disease.

Generalized Lymphangiomatosis: Radiologic Findings in Three Pediatric Patients

Generalized lymphangiomatosis is a rare disease that is characterized by widespread bony and soft tissue involvement of lymphangioma. Radiological evaluation is crucial because the site and extent of the lymphangioma are important prognostic factors. We reported here on three cases of generalized lymphangiomatosis and all three cases showed similar radiologic findings, but a different clinical course. The CT, US and MR images showed sharply defined, non-enhanced cystic lesions involving the mediastinum, bones, spleen, lung and lower neck. The whole body MR imaging with the short tau inversion recovery (STIR) sequence showed good capability for evaluating the extent of disease.

Stress Myocardial Perfusion CT in Patients Suspected of Having Coronary Artery Disease: Visual and Quantitative Analysis—Validation by Using Fractional Flow Reserve

PURPOSE To assess the diagnostic accuracy of stress myocardial perfusion computed tomography (CT) by using visual and quantitative analytic methods in patients with coronary artery disease, with fractional flow reserve (FFR) as a reference standard. MATERIALS AND METHODS The institutional review board approved the study, and written informed consent was obtained from all patients. The diagnostic accuracy of myocardial perfusion CT was assessed for 75 patients who underwent myocardial perfusion CT and conventional coronary angiography with reference to hemodynamically significant stenosis, defined as the presence of an FFR of 0.8 or less or an angiographically severe (≥90%) stenosis. Results of quantitative analysis of myocardial perfusion CT data were compared with those of visual analysis by using areas under the receiver operating characteristic curve (AUCs). RESULTS Among the 75 patients and 210 epicardial arteries, 61 patients (81%) with 86 arteries (41%) had hemodynamically significant stenosis. The per-patient sensitivity and specificity of the visual assessment of myocardial perfusion CT data for all patients were 89% and 86%, respectively. At per-vessel analysis, the sensitivities and specificities, respectively, of myocardial perfusion CT were 80% and 95% for all vessels, 85% and 100% for 63 vessels with severe coronary calcification (defined as an Agatston score > 400), and 76% and 91% for 56 vessels in patients with multivessel disease. In severely calcified vessels, visual assessment of myocardial perfusion CT data in combination with CT angiography provided incremental value over CT angiography alone for the detection of myocardial ischemia (integrated discrimination improvement index, 0.38; P < .001). Quantitative assessment of transmural perfusion ratio had a lower AUC than visual analysis of myocardial perfusion CT (0.759 vs 0.877, P = .002). CONCLUSION Stress myocardial perfusion CT provides incremental value over CT angiography in patients with a high calcium score for the detection of myocardial ischemia as defined by FFR.

Three-Dimensional Printing: Basic Principles and Applications in Medicine and Radiology

The advent of three-dimensional printing (3DP) technology has enabled the creation of a tangible and complex 3D object that goes beyond a simple 3D-shaded visualization on a flat monitor. Since the early 2000s, 3DP machines have been used only in hard tissue applications. Recently developed multi-materials for 3DP have been used extensively for a variety of medical applications, such as personalized surgical planning and guidance, customized implants, biomedical research, and preclinical education. In this review article, we discuss the 3D reconstruction process, touching on medical imaging, and various 3DP systems applicable to medicine. In addition, the 3DP medical applications using multi-materials are introduced, as well as our recent results.

Diagnostic performance of on-site CT-derived fractional flow reserve versus CT perfusion

Aims To compare the diagnostic accuracy of on-site computed tomography (CT)-derived fractional flow reserve (FFR) and stress CT myocardial perfusion (CTP) in patients with coronary artery disease. Methods and results Using a prospective CTP registry, 72 patients with invasive FFR were enrolled. CT-derived FFR was computed on-site using rest-phase CTP data. The diagnostic accuracies of coronary CT angiography (CCTA), CT-derived FFR, and stress CTP were evaluated using an area under the receiver-operating characteristic curve (AUC) with invasive FFR as a reference standard. Logistic regression and the net reclassification index (NRI) were used to evaluate incremental differences in CT-derived FFR or CTP compared with CCTA alone. The per-vessel prevalence of haemodynamically significant stenosis (FFR ≤ 0.80) was 39% (54/138). Per-vessel sensitivity and specificity were 94 and 66% for CCTA, 87 and 77% for CT-derived FFR, and 79 and 91% for CTP, respectively. There was no significant difference in the AUC values of CT-derived FFR and CTP (P = 0.845). The diagnostic performance of CCTA (AUC = 0.856) was improved by combining it with CT-derived FFR (AUC = 0.919, P = 0.004, NRI = 1.01) or CTP (AUC = 0.913, P = 0.004, NRI = 0.66). CT-derived FFR values had a moderate correlation with invasive FFR (r = 0.671, P < 0.001). Conclusion On-site CT-derived FFR combined with CCTA provides an incremental diagnostic improvement over CCTA alone in identifying haemodynamically significant stenosis defined by invasive FFR, with a diagnostic accuracy comparable with CTP.