Impact of Diabetes Control on Subclinical Atherosclerosis: Analysis from Coronary Computed Tomographic Angiography Registry

Background@#There are limited data on the impact of diabetes control on the risk of subclinical coronary atherosclerosis. @*Methods@#We analyzed 6,434 consecutive asymptomatic individuals without previous history of coronary artery disease who underwent coronary computed tomographic angiography (CCTA) (mean age, 53.7±7.6 years and 4,694 men [73.0%]). The degree and extent of subclinical coronary atherosclerosis were assessed by CCTA, and ≥50% diameter stenosis was defined as significant. A cardiac event was defined as a composite of all-cause death, myocardial infarction, unstable angina, or coronary revascularization. Study participants were categorized as normal (n=5,319), controlled diabetes (glycosylated hemoglobin [HbA1c] <7%, n=747), or uncontrolled diabetes (HbA1c ≥7%, n=368), respectively. @*Results@#Compared with normal individuals, there were no statistically significant differences in the risk of for any atherosclerotic plaque (odds ratio [OR], 1.16; 95% confidence interval [CI], 0.98 to 1.38; p=0.086) and significant coronary artery stenosis (OR, 1.08; 95% CI, 0.82 to 1.42; p=0.583) in controlled diabetic individuals. In contrast, uncontrolled diabetic individuals had consistently higher risks of any atherosclerotic plaque (OR, 2.16; 95% CI, 1.70 to 2.75; p<0.001) and significant coronary artery stenosis (OR, 3.34; 95% CI, 2.52 to 4.43; p<0.001) than normal individuals. During a follow-up of median 5.4 years, there was no significant difference in cardiac events between normal and controlled diabetic individuals (p=0.365). However, uncontrolled diabetes was associated with an increased risk of cardiac events compared with normal individuals (P<0.001) and controlled diabetic individuals (p=0.023). @*Conclusion@#Asymptomatic uncontrolled diabetes was associated with significant subclinical coronary atherosclerosis with subsequent high risk for cardiac events.

Left Ventricular Noncompaction in Adults: Imaging and Clinical Findings in 63 Patients

PURPOSE@#To describe imaging and clinical findings for a left ventricular noncompaction (LVNC) in the adult.@*MATERIALS AND METHODS@#From 2000 to 2014, 63 patients were diagnosed with LVNC by echocardiography, computed tomography, and magnetic resonance imaging at our hospital. Baseline characteristics, clinical manifestations, combined cardiac or systemic anomalies, and imaging findings were reviewed. We made a comparison between the isolated and combined disease groups.@*RESULTS@#Among 63 patients with LVNC, 32 (51%) patients did not have combined cardiac anomalies (isolated disease group). The mean age at the initial diagnosis was higher in the isolated than in the combined disease group (54.2 years vs. 40.2 years, p < 0.001). The combined disease group presented symptoms more frequently at initial diagnosis than the isolated disease group (94% vs. 75%, p = 0.082). Heart failure symptoms were the most common adverse events (60.3% in all patients). Thromboembolic events developed in 20 patients, and were more frequent in the combined disease group than in the isolated disease group (39% vs. 26%, p = 0.279). The most common cardiac abnormality was dilated cardiomyopathy (n = 15, 24%). There was no significant difference in the mean noncompacted/compacted ratios between both of the disease groups.@*CONCLUSION@#Isolated and combined LVNC disease groups showed differences in age at diagnosis and clinical manifestations. The clinical and imaging findings may be helpful to better understand LVNC.

2017 Multimodality Appropriate Use Criteria for Noninvasive Cardiac Imaging: Expert Consensus of the Asian Society of Cardiovascular Imaging

In 2010, the Asian Society of Cardiovascular Imaging (ASCI) provided recommendations for cardiac CT and MRI, and this document reflects an update of the 2010 ASCI appropriate use criteria (AUC). In 2016, the ASCI formed a new working group for revision of AUC for noninvasive cardiac imaging. A major change that we made in this document is the rating of various noninvasive tests (exercise electrocardiogram, echocardiography, positron emission tomography, single-photon emission computed tomography, radionuclide imaging, cardiac magnetic resonance, and cardiac computed tomography/angiography), compared side by side for their applications in various clinical scenarios. Ninety-five clinical scenarios were developed from eight selected pre-existing guidelines and classified into four sections as follows: 1) detection of coronary artery disease, symptomatic or asymptomatic; 2) cardiac evaluation in various clinical scenarios; 3) use of imaging modality according to prior testing; and 4) evaluation of cardiac structure and function. The clinical scenarios were scored by a separate rating committee on a scale of 1–9 to designate appropriate use, uncertain use, or inappropriate use according to a modified Delphi method. Overall, the AUC ratings for CT were higher than those of previous guidelines. These new AUC provide guidance for clinicians choosing among available testing modalities for various cardiac diseases and are also unique, given that most previous AUC for noninvasive imaging include only one imaging technique. As cardiac imaging is multimodal in nature, we believe that these AUC will be more useful for clinical decision making.

Serum Total Bilirubin Levels Provide Additive Risk Information over the Framingham Risk Score for Identifying Asymptomatic Diabetic Patients at Higher Risk for Coronary Artery Stenosis

BACKGROUND: The diagnosis of coronary artery disease (CAD) is often delayed in patients with type 2 diabetes. Serum total bilirubin levels are inversely associated with CAD. However, no studies have examined whether this can be used as a biochemical marker for identifying asymptomatic diabetic patients at higher risk for having obstructive CAD. METHODS: We performed a cross-sectional study of 460 consecutive asymptomatic patients with type 2 diabetes. All patients underwent coronary computed tomographic angiography, and their serum total bilirubin levels were measured. Obstructive CAD was defined as > or =50% diameter stenosis in at least one coronary artery. RESULTS: Serum total bilirubin tertiles showed an inverse association with the prevalence of obstructive CAD. In multivariate logistic regression analysis, the odds ratio for the highest versus the lowest tertile of total bilirubin was 0.227 (95% confidence interval [CI], 0.130 to 0.398), and an increment of 1 micromol/L in serum total bilirubin level was associated with a 14.6% decrease in obstructive CAD after adjustment for confounding variables. Receiver operating characteristic curve analysis showed that the area under the curve for the Framingham Risk Score (FRS) plus serum total bilirubin level was 0.712 (95% CI, 0.668 to 0.753), which is significantly greater than that of the FRS alone (P=0.0028). CONCLUSION: Serum total bilirubin level is inversely associated with obstructive CAD and provides additive risk information over the FRS. Serum total bilirubin may be helpful for identifying asymptomatic patients with type 2 diabetes who are at higher risk for obstructive CAD.

Current Roles and Future Applications of Cardiac CT: Risk Stratification of Coronary Artery Disease

Cardiac computed tomography (CT) has emerged as a noninvasive modality for the assessment of coronary artery disease (CAD), and has been rapidly integrated into clinical cares. CT has changed the traditional risk stratification based on clinical risk to image-based identification of patient risk. Cardiac CT, including coronary artery calcium score and coronary CT angiography, can provide prognostic information and is expected to improve risk stratification of CAD. Currently used conventional cardiac CT, provides accurate anatomic information but not functional significance of CAD, and it may not be sufficient to guide treatments such as revascularization. Recently, myocardial CT perfusion imaging, intracoronary luminal attenuation gradient, and CT-derived computed fractional flow reserve were developed to combine anatomical and functional data. Although at present, the diagnostic and prognostic value of these novel technologies needs to be evaluated further, it is expected that all-in-one cardiac CT can guide treatment and improve patient outcomes in the near future.

Managing health technologies

No abstract available.

Use of big data for evidence-based healthcare

Data pools and their integration are fueling the big data revolution in health care with the recent advances in information technology. Korea has shown tremendous promise in the utilization of big data for its advanced technology, computerized health data, and unique identifiers. However, the Personal Information Protection Act (PIPA) severely limits access to personal identifiers, which has discouraged the use of health data even for the public good. In contrast, western countries have focused on research without the use of identifiers, which has augmented the use of the available data while maintaining and respecting privacy; they have allowed some exemptions of informed consent and utilized limited data sets, which have the identifiers removed. The amount of research output has increased rapidly and an in-depth understanding of cancer has been made possible based on the linkage of Surveillance, Epidemiology, and End Results (SEER) and Medicare in the US. More than 700 projects covering a wide range of medical areas have been conducted, which has led to changes in clinical practice based on the Western Australian Data Linkage System. Although rare, evidence-driven decisions based on data linkage have been found in some cases in Korea; the adoption of prostate cancer screening as a national screening program was suspended as its cost-effectiveness has not been verified on the basis of data linkage by the National Evidence-Based Healthcare Collaboration Agency. For the active use of health data, there is an urgent need to amend PIPA, prepare regulations for data analysis, and foster collaboration among data-related institutions. Great projects based on data linkage will guarantee the world's leading research output and will be major sources for moving forward to success.

High-Resolution Diffusion Tensor MR Imaging for Evaluating Myocardial Anisotropy and Fiber Tracking at 3T: the Effect of the Number of Diffusion-Sensitizing Gradient Directions

OBJECTIVE: We wanted to evaluate the effect of the number of diffusion-sensitizing gradient directions on the image quality for evaluating myocardial anisotropy and fiber tracking by using in vitro diffusion tensor MR imaging (DT-MRI). MATERIALS AND METHODS: The DT-MR images, using a SENSE-based echoplanar imaging technique, were acquired from ten excised porcine hearts by using a 3T MR scanner. With a b-value of 800 s/mm2, the diffusion tensor images were obtained for 6, 15 and 32 diffusion-sensitizing gradient directions at the midventricular level. The number of tracked fibers, the fractional anisotropy (FA), and the length of the tracked fibers were measured for the quantitative analysis. Two radiologists assessed the image quality of the fiber tractography for the qualitative analysis. RESULTS: By increasing the number of diffusion-sensitizing gradient directions from 6 to 15, and then to 32, the FA and standard deviation were significantly reduced (p < 0.01), and the number of tracked fibers and the length of the tracked fibers were significantly increased (p < 0.01). The image quality of the fiber tractography was significantly increased with the increased number of diffusion-sensitizing gradient directions (p < 0.01). CONCLUSION: The image quality of in vitro DT-MRI is significantly improved as the number of diffusion-sensitizing gradient directions is increased.

Abnormal Motion of the Interventricular Septum after Coronary Artery Bypass Graft Surgery: Comprehensive Evaluation with MR Imaging

OBJECTIVE: To define the mechanism associated with abnormal septal motion (ASM) after coronary artery bypass graft surgery (CABG) using comprehensive MR imaging techniques. MATERIALS AND METHODS: Eighteen patients (mean age, 58 +/- 12 years; 15 males) were studied with comprehensive MR imaging using rest/stress perfusion, rest cine, and delayed enhancement (DE)-MR techniques before and after CABG. Myocardial tagging was also performed following CABG. Septal wall motion was compared in the ASM and non-ASM groups. Preoperative and postoperative results with regard to septal wall motion in the ASM group were also compared. We then analyzed circumferential strain after CABG in both the septal and lateral walls in the ASM group. RESULTS: All patients had normal septal wall motion and perfusion without evidence of non-viable myocardium prior to surgery. Postoperatively, ASM at rest and/or stress state was documented in 10 patients (56%). However, all of these had normal rest/stress perfusion and DE findings at the septum. Septal wall motion after CABG in the ASM group was significantly lower than that in the non-ASM group (2.1+/-5.3 mm vs. 14.9+/-4.7 mm in the non-ASM group; p < 0.001). In the ASM group, the degree of septal wall motion showed a significant decrease after CABG (preoperative vs. postoperative = 15.8+/-4.5 mm vs. 2.1+/-5.3 mm; p = 0.007). In the ASM group after CABG, circumferential shortening of the septum was even larger than that of the lateral wall (-20.89+/-5.41 vs. -15.41+/-3.7, p < 0.05) CONCLUSION: Abnormal septal motion might not be caused by ischemic insult. We suggest that ASM might occur due to an increase in anterior cardiac mobility after incision of the pericardium.

Exercise Training Improves Age-Related Myocardial Metabolic Derangement: Proton Magnetic Resonance Spectroscopy Study in the Rat Model

BACKGROUND AND OBJECTIVES: The objective of this study was to determine whether long-term exercise training will improve age-related cardiac metabolic derangement using proton magnetic resonance (MR) spectroscopy. MATERIALS AND METHODS: Young and old male Fischer 344 rats were assigned to sedentary controls groups {young control (YC) group-3 months of age: YC, n=10; old control (OC) group-22 months of age: OC, n=10}, and an exercise training group (OT, n=5). After 12-week of treadmill exercise training, MR spectroscopy at 4.7 T was performed to assess myocardial energy metabolism: measurements of myocardial creatine-to-water ratio (Scr/Sw) were performed using the XWIN-NMR software. RESULTS: Exercise capacity was 14.7 minutes greater in OT than that in OC (20.1+/-1.9 minutes in OT, 5.4+/-2.3 minutes in OC; p0.05). The creatine-to-water ratios in the interventricular septa of YC did not differ significantly from that of OT (0.00131+/-0.00025 vs. 0.00127+/-0.00031; p=0.37). However, OC showed significant reduction in creatine-to-water ratio compared to OT (0.00096+/-0.00025 vs. 0.00127+/-0.00031; p<0.001). Mean total creatine concentrations in the myocardium were similar between YC and OT (13.3 +/-3.6 vs. 11.5+/-4.1 mmol/kg wet weight; p=0.29). In contrast, the mean total creatine concentration of OC was significantly reduced compared to OT (6.8+/-3.2 vs. 11.5+/-4.1 mmol/kg wet weight; p=0.03). CONCLUSION: Our findings suggest that long-term exercise training in old rats induced prevention of age-related deterioration in myocardial metabolism.

Unusual CT Findings of a Benign Metastasizing Leiomyoma Presenting with Multiple Cavitary Nodules: A Case Report

A benign metastasizing leiomyoma is a rare condition that affects women with a history of uterine leiomyoma, usually after a myomectomy or hysterectomy. Typical radiographic findings include well-circumscribed solitary or multiple pulmonary nodules ranging from a few millimeters to several centimeters in diameter and scattered among the normal interstitium. We report a case of a benign metastasizing leiomyoma that manifested with multiple cavitary nodules in a 46-year-old woman with no previous history of a myomectomy or hysterectomy.

Comparison of Transaxial Source Images and 3-Plane, Thin-Slab Maximal Intensity Projection Images for the Diagnosis of Coronary Artery Stenosis with Using ECG-Gated Cardiac CT

OBJECTIVE: We wanted to compare the transaxial source images with the optimized three plane, thin-slab maximum intensity projection (MIP) images from electrocardiographic (ECG)-gated cardiac CT for their ability to detect hemodynamically significant stenosis (HSS), and we did this by means of performing a receiver operating characteristic (ROC) analysis. MATERIALS AND METHODS: Twenty-eight patients with a heart rate less than 66 beats per minute and who were undergoing both retrospective ECG-gated cardiac CT and conventional coronary angiography were included in this study. The contrast-enhanced CT scans were obtained with a collimation of 16x0.75-mm and a rotation time of 420 msec. The transaxial images were reconstructed at the mid-diastolic phase with a 1-mm slice thickness and a 0.5-mm increment. Using the transaxial images, the slab MIP images were created with a 4-mm thickness and a 2-mm increment, and they covered the entire heart in the horizontal long axis (4 chamber view), in the vertical long axis (2 chamber view) and in the short axis. The transaxial images and MIP images were independently evaluated for their ability to detect HSS. Conventional coronary angiograms of the same study group served as the standard of reference. Four radiologists were requested to rank each image with using a five-point scale (1 = definitely negative, 2 = probably negative, 3 = indeterminate, 4 = probably positive, and 5 = definitely positive) for the presence of HSS; the data were then interpreted using ROC analysis. RESULTS: There was no statistical difference in the area under the ROC curve between transaxial images and MIP images for the detection of HSS (0.8375 and 0.8708, respectively; p > 0.05). The mean reading time for the transaxial source images and the MIP images was 116 and 126.5 minutes, respectively. CONCLUSION: The diagnostic performance of the MIP images for detecting HSS of the coronary arteries is acceptable and this technique's ability to detect HSS is comparable to that of the transaxial source images.

ECG-gated CT Angiography for the Assessment of Coronary bypass Graft Patency: the Influence of Heart Rate, Type of bypass Graft, Target Vessel and Surgical Technique on the Diagnostic Accuracy

PURPOSE: We wanted to evaluate the accuracy of using ECG-gated CT angiography (CTA) for the assessment of coronary bypass graft patency. MATERIALS AND METHODS: This study included 48 patients who underwent both CTA and conventional angiography to evaluate coronary bypass graft patency. CTA was performed with a 16-detector row multislice CT scanner. We calculated the sensitivity and specificity of CTA to detect occlusion of bypass graft that was equal to or greater than 50% of the expected diameter. Conventional angiography served as a gold standard. A total 160 grafts were evaluated. The diagnostic accuracy was evaluated according to a variety of factors (heart rate, types of bypass graft, target vessel, and surgical techniques). RESULTS: The overall sensitivity, specificity and accuracy of CTA were 83.9%, 95.4% and 93.1%, respectively. There was no significant statistical difference for each factor according to Fisher's exact test. Although the grafts anastomosed to the left circumflex arterial branches and a high heart rate showed a statistically significant high risk of misdiagnosis on the simple logistic regression test, a high heart rate was the only significant factor on the multiple logistic regression test (odds, 5.9). CONCLUSION: CTA provides for good noninvasive evaluation of the coronary bypass graft patency. The heart rate and the anastomosed vessel are factors that can influence the accuracy.

Usefulness of ACR MRI Phantom for Quality Assurance of MRI Instruments

PURPOSE: To examine whether the ACR phantom could be used in quality standards for magnetic resonance imaging (MRI) instruments in Korea. MATERIALS AND METHODS: We conducted the phantom test using the ACR MRI phantom in 20 MRI instruments currently used in Korea. According to ACR criteria, we acquired the phantom images which were then assessed by the following seven tests: geometric accuracy, high spatial resolution, slice thickness accuracy, slice position accuracy, image intensity uniformity, percent signal ghosting, and low contrast object detectability. The phantom images were interpreted by three experienced radiologists according to ACR criteria. Then, we examined the failure rate of each test and evaluated the inter-observer variation in the measurements and test failure. RESULTS: The failure rate of each test could be broken into the following components: geometric accuracy (11-21%), high contrast spatial resolution (10-15%), slice thickness accuracy (6-22%), slice position accuracy (5-17%), image intensity uniformity (6%), percent signal ghosting (16%), and low contrast object detectability (8-10%). In this series, all the failure rates were less than 30%. In addition, no inter-observer variation was seen in the measurements and test failure. CONCLUSION: ACR MRI phantom promises to be established as the standard phantom for MRI instruments in Korea because of its objectivity in assessing the phantom images.

Subtle Pleural Metastasis without Large Effusion in Lung Cancer Patients: Preoperative Detection on CT

OBJECTIVE: We wanted to describe the retrospective CT features of subtle pleural metastasis without large effusion that would suggest inoperable lung cancer. MATERIALS AND METHODS: We enrolled 14 patients who had open thoracotomy attempted for lung cancer, but they were proven to be inoperable due to pleural metastasis. Our study also included 20 control patients who were proven as having no pleural metastasis. We retrospectively evaluated the nodularity and thickening of the pleura and the associated pleural effusion on the preoperative chest CT scans. We reviewed the histologic cancer types, the size, shape and location of the lung cancer and the associated mediastinal lymphadenopathy. RESULTS: Subtle pleural nodularity or focal thickening was noted in seven patients (50%) having pleural metastasis and also in three patients (15%) of control group who were without pleural metastasis. More than one of the pleural changes such as subtle pleural nodularity, focal thickening or effusion was identified in eight (57%) patients having pleural metastasis and also in three patients (15%) of the control group, and these findings were significantly less frequent in the control group patients than for the patients with pleural metastasis (p = 0.02). The histologic types of primary lung cancer in patients with pleural metastasis revealed as adenocarcinoma in 10 patients (71%) and squamous cell carcinoma in four patients (29%). The location, size and shape of the primary lung cancer and the associated mediastinal lymphadenopathy showed no significant correlation with pleural metastasis. CONCLUSION: If any subtle pleural nodularity or thickening is found on preoperative chest CT scans of patients with lung cancer, the possibility of pleural metastasis should be considered.

Myocardial Viability: Comparison of Free-Breathing Navigator-echo-gated Three-Dimensional Inversion-Recovery Gradient-Echo MR and Standard Multiple Breath-Hold Two-Dimensional Inversion-Recovery Gradient-Echo MR

PURPOSE: To compare a free-breathing, navigator-echo-gated, three-dimensional, inversion-recovery, gradient-echo, MR pulse sequence (3D-MRI) with standard, multiple breath-hold, two-dimensional, inversion-recovery, gradient-echo MR (2D-MRI) for the evaluation of delayed hyperenhancement of nonviable myocardium in patients with chronic ischemic heart disease. MATERIALS AND METHODS: Ten patients with chronic ischemic heart disease were enrolled in this study. MRI was performed on a 1.5-T system. 3D-MRI was obtained in the short axis plane at 10 minutes after the administration of Gd-DTPA (0.2 mmol/kg, 4 cc/sec). Prospective gating of the acquisition based on the navigator echo was applied. 2D-MRI was performed immediately after finishing 3D-MRI. The area of total and hyperenhanced myocardium measured on both image sets was compared with paired Student t-test and Bland-Altman method. By using a 60-segment model, the transmural extent and segmental width of the hyperenhanced area were recorded by 3-scale grading method. The agreement between the two sequences was evaluated with kappa statistics. We also evaluated the agreement of hyperenhancement among the three portions (apical, middle and basal portion) of the left ventricle with kappa statistics. RESULTS: The two sequences showed good agreement for the measured area of total and hyperenhanced myocardium on paired t-test (p=0.11 and p=0.34, respectively). No systematic bias was shown on Bland-Altman analysis. Good agreement was found for the segmental width (Kappa=0.674) and transmural extent (Kappa=0.615) of hyperenhancement on the segmented analysis. However, the agreement of the transmural extent of hyperenhancement in the apical segments was relatively poor compared with that in the middle or basal portions. CONCLUSION: This study showed good agreement between 3D-MRI and 2D-MRI in evaluation of non-viable myocardium. Therefore, 3D-MRI may be useful in the assessment of myocardial viability in patients with dyspnea and children because it allows free-breathing during the examination.

Coronary Angiography with Multidetector row Computed Tomography: Part I - Technical Aspects

Various invasive and non-invasive imaging techniques have been used for the diagnosis of cardiac disease. The recently introduced multidetector row CT (MDCT) shows rapid scan speed, high temporal resolution and large volume coverage in a single breath-hold. MDCT opens a new horizon for cardiac imaging because noninvasive coronary artery imaging has become feasible using MDCT. In this article, we illustrate the technical aspects of coronary CT angiography using MDCT.

Localized 1H-MR Spectroscopy in Moyamoya Disease before and after Revascularization Surgery

OBJECTIVE: To evaluate, using localized proton magnetic resonance spectroscopy (1H-MRS), the cerebral metabolic change apparent after revascularization surgery in patients with moyamoya disease. MATERIALS AND METHODS: Sixteen children with moyamoya disease and eight age-matched normal controls underwent MR imaging, MR angiography, conventional angiography, and 99mTc- ECD SPECT. Frontal white matter and the basal ganglia of both hemispheres were subjected to localized 1H-MRS, and after revascularization surgery, four patients underwent follow-up 1H-MRS. RESULTS: Decreased NAA/Cr ratios (1.35+/-0.14 in patients vs. 1.55+/-0.24 in controls) and Cho/Cr ratios (0.96+/-0.13 in patients vs. 1.10+/-0.11 in controls) were observed in frontal white matter. After revascularization surgery, NAA/Cr and Cho/Cr ratios in this region increased. In the basal ganglia, there is no abnormal metabolic ratios. CONCLUSION: Localized 1H-MRS revealed abnormal metabolic change in both hemispheres of children with moyamoya disease. Because of its non-invasive nature, 1H-MRS is potentially useful for the preoperative evaluation of metabolic abnormalities and their postoperative monitoring.

16-MDCT : A New Modality for Diagnosis of Cardiac Diseases

Since the advent of 16-MDCT in the clinical diagnosis, a paradigm shift is required in the diagnostic algorithm of cardiovascular diseases owing to its revolutionary technical advances. 16-MDCT provides less than 1 mm of high spatial resolution even in z-direction by using detectors with less than 0.75 mm collimation, which in turn allows for volumetric scanning with isotropic 3-dimensional resolution. This high spatial resolution of 16-MDCT enables one to obtain high quality images of the small vessels such as coronary arteries with diameter < 1 mm. For imaging of the heart, scanning with a high temporal resolution is particularly important because of the strong movement during the cardiac cycle. 16-MDCT allows images with a high temporal resolution, less than 250 msec, enough to freeze the cardiac motion. Furthermore, by using ECG information that is recorded simultaneouly with the image acquisition, images synchronized to the specific cardiac phase can either be scanned or post-processed according to the technique of ECG-gating. In order to eliminate the motion artifact from respiratory motion, scanning must be completed within a single breathholding time. By adopting 12~16 detector arrays and less than 0.5 sec of gantry rotation time, imaging of the whole heart with submillimeter spatial resolution can be covered within 20 seconds of breathholding time. Major clinical applications of 16-MDCT in cardiac diseases inlcude detection of coronary stenosis and atherosclerotic plaque, coronary calcium scoring, evaluation of the patients after coronary angioplasty or coronary arterial by-pass graft, assessment of the cardiac valve morphology and function, and ventricular function and perfusion. Among these, currently the most practical area of 16-MDCT application is post-CABG evaluation and the most imporatnt and promising area will be assessment of native coronary arteries for detection of stenotic vessels and for detecting and differentiating atherosclerotic lesions over a spectrum of vulnerable, soft, fibrotic, and calcified plaques. In this review, important technical aspects together with clinical applications of 16-MDCT in diagnosis of cardiovascular diseases will be presented.

Percutaneous Fine Needle Aspiration Biopsy for the Intrathoracic Lesions: What is the Meaning of Non-Diagnostic Results?

PURPOSE: To know what is the meaning of non-diagnostic results of fine needle aspiration biopsy (FNAB) and whether repeated aspiration is needed or not in those situations. MATERIALS AND METHODS: We reviewed 1845 patients who underwent FNAB from 1997 to 2001. Non-diagnostic results of the first FNAB were divided into four groups: insufficient number of cells, inflammatory cells, necrotic debris and atypical cells. We analyzed final diagnosis of 531 patients who had non-diagnostic results from the first FNAB. Among them, 207 lesions were re-biopsied because of clinical and radiologic suspicion of malignancy. The diagnostic yield of repeated FNAB was analyzed and compared with the results of the first FNAB. RESULTS: Among 255 cases with "inflammatory cells only" results, 120 cases were confirmed benignancy on follow-up. Twenty nine of 50 atypical cells (58%) were malignant on follow-up. One hundred one of 207 repeated FNAB resulted in the non-diagnostic reports, and 106 of 207 repeated FNAB were diagnosed as specific diagnosis. Among thirty lesions showing atypical cells on the repeated FNAB, 22 (73%) were identified as malignant neoplasms. CONCLUSION: When the specimen of FNAB shows atypical cells, the possibility of malignancy is very high. When the results of FNAB is non-diagnostic in the cases with clinical and radiological suspicion of malignancy, repeated FNAB procedures should be seriously considered and will be helpful for accurate specific diagnosis.