CT coronary angiography is popular nowadays because of the wide use of multidetector CT. Multidetector CT has an isotropic resolution at 0.3~0.4 mm and temporal resolution at 80~210 ms. With the retrospective EKG-gated reconstruction technique and these high spatial and temporal resolutions, coronary artery imaging is possbile with CT. EKG-gated CT consists of EKG recording and continuous CT scanning with a low-pitch value. The CT data from certain periods of cardiac cycles, in which the cardiac motion is minimal, are retrospectively selected and reconstructed to whole heart volume data, and then the motion freezing entire heart CT image can be obtained. Because of its limited temporal resolution, EKG-gated CT requires lowering of the heart rate by beta-blocker medication in most cases. The lower heart rate increases diagnostic accuracy of coronary CT angiography. The nitroglycerin can also be used for coronary artery dilatation. Coronary CT angiography is a very reliable method for evaluating coronary artery stenosis with a noninvasive manner. The potential hazard comes from the use of ionized radiation and iodine contrast media. The typical radiation dose for coronary CT angiography is reported as 6.7 ~ 13.0mSv. This radiation dose is equivalent to those for other noninvasive coronary artery evaluating tools with radioactive isotopes and higher than the dose for conventional coronary angiography.
Angiography* ; Cardiac Volume ; Contrast Media ; Coronary Angiography ; Coronary Stenosis ; Coronary Vessels ; Dilatation ; Electrocardiography ; Freezing ; Heart ; Heart Rate ; Iodine ; Nitroglycerin ; Radioisotopes ; Retrospective Studies ; Tomography, X-Ray Computed

The radiation exposure from diagnostic medical imaging has increased. The potential risk from radiation exposure of the patient also has increased even though the risk from a small amount of radiation exposure has not been clearly demonstrated. Any medical radiation exposure must be justified and the examinations which use ionizing radiation must be optimized. The education of the referring physician and radiologist are important. However, stronger regulation is essential to control medical radiation exposure. Many national and international organizations have made a significant effort to regulate and monitor medical radiation exposure using guidelines, accreditation, or even laws. Medical radiation exposure must be controlled, and this could be achieved by continuous interest from health professionals and organizations.
Accreditation ; Diagnostic Imaging ; Health Occupations ; Humans ; Jurisprudence ; Organothiophosphorus Compounds ; Radiation Protection ; Radiation, Ionizing

Carotid Doppler ultrasonography is a popular tool for evaluating atherosclerosis of the carotid artery. Its two-dimensional gray scale can be used for measuring the intima-media thickness, which is very good biomarker for atherosclerosis and can aid in plaque characterization. The plaque morphology is related to the risk of stroke. The ulceration of plaque is also known as one of the strong predictors of future embolic event risk. Color Doppler ultrasonography and pulse Doppler ultrasonography have been used for detecting carotid artery stenosis. Doppler ultrasonography has unique physical properties. The operator should be familiar with the physics and other parameters of Doppler ultrasonography to perform optimal Doppler ultrasonography studies.
Atherosclerosis ; Carotid Arteries ; Carotid Stenosis ; Plaque, Atherosclerotic ; Stroke ; Ulcer ; Ultrasonography ; Ultrasonography, Doppler* ; Ultrasonography, Doppler, Color

With technical advances in computed tomography and the introduction of non-ionic low- or iso-osmolar iodinated contrast media (ICM), the use of ICM and the occurrence of ICM-related hypersensitivity reactions (HSRs) has rapidly increased. Although ICM-related HSRs are known to be mild, they still represent life-threatening events in rare instances. It is therefore important to prevent recurrent HSRs in high-risk patients. Changing the culprit contrast agent is a powerful known tool for reducing the recurrence rate of HSRs. Based on the large body of evidence, the American College of Radiology manual on contrast media (latest version 10.3) suggests that changing the ICM within the same class may help reduce the likelihood of a subsequent contrast reaction. Furthermore, the European Society of Urogenital Radiology guidelines on contrast agents (latest version 10) also recommends using a different contrast agent with previous contrast agent reactors to reduce the risk of an acute reaction. In this article, we review the necessity and clinical efficacy of changing the culprit ICM for high-risk patients at the time of re-exposure to prevent ICM-related HSRs and minimize the risk of fatality.
Contrast Media ; Humans ; Hypersensitivity ; Primary Prevention ; Recurrence ; Treatment Outcome

With technical advances in computed tomography and the introduction of non-ionic low- or iso-osmolar iodinated contrast media (ICM), the use of ICM and the occurrence of ICM-related hypersensitivity reactions (HSRs) has rapidly increased. Although ICM-related HSRs are known to be mild, they still represent life-threatening events in rare instances. It is therefore important to prevent recurrent HSRs in high-risk patients. Changing the culprit contrast agent is a powerful known tool for reducing the recurrence rate of HSRs. Based on the large body of evidence, the American College of Radiology manual on contrast media (latest version 10.3) suggests that changing the ICM within the same class may help reduce the likelihood of a subsequent contrast reaction. Furthermore, the European Society of Urogenital Radiology guidelines on contrast agents (latest version 10) also recommends using a different contrast agent with previous contrast agent reactors to reduce the risk of an acute reaction. In this article, we review the necessity and clinical efficacy of changing the culprit ICM for high-risk patients at the time of re-exposure to prevent ICM-related HSRs and minimize the risk of fatality.

With technical advances in computed tomography and the introduction of non-ionic low- or iso-osmolar iodinated contrast media (ICM), the use of ICM and the occurrence of ICM-related hypersensitivity reactions (HSRs) has rapidly increased. Although ICM-related HSRs are known to be mild, they still represent life-threatening events in rare instances. It is therefore important to prevent recurrent HSRs in high-risk patients. Changing the culprit contrast agent is a powerful known tool for reducing the recurrence rate of HSRs. Based on the large body of evidence, the American College of Radiology manual on contrast media (latest version 10.3) suggests that changing the ICM within the same class may help reduce the likelihood of a subsequent contrast reaction. Furthermore, the European Society of Urogenital Radiology guidelines on contrast agents (latest version 10) also recommends using a different contrast agent with previous contrast agent reactors to reduce the risk of an acute reaction. In this article, we review the necessity and clinical efficacy of changing the culprit ICM for high-risk patients at the time of re-exposure to prevent ICM-related HSRs and minimize the risk of fatality.

BACKGROUND: The current study aimed at elucidating the anatomical basis for a supraclavicular approach for central venous catheterization using three-dimensional computed tomography (3D-CT). METHODS: Retrospective review of CT images from 60 adult patients with normal body build was performed using 3D-CT reconstruction. Right-sided approach was assumed, and the skin entry point was decided as a point above the subclavian vein at the supraclavicular fossa. Measured parameters were; angles of the clavicle (Aclv) and the subclavian vein (Ascv) to the coronal plane, the distance from the clavisternomastoid angle to the skin entry point (Dse), the optimal angle of needle insertion (Ains) targeting the confluence between the internal jugular vein and the subclavian vein, the distance from the skin entry point to the confluence (Dconf), and the diameter of the confluence (Dia). Descriptive statistics were performed for the measured values. Correlation test was performed between Ascv and Aclv. RESULTS: Measured values were; Aclv = 8.0 degrees, Ascv = 5.7 degrees, Dse = 12.5 mm, Ains = 40 degrees, Dconf = 20.5 mm, and Dia = 18.1 mm. Ascv demonstrated positive correlation with corresponding Aclv (r = 0.494, P < 0.001). CONCLUSIONS: Optimal guideline for the supraclavicular approach can be provided via 3D-CT investigation. Forty degrees of needle direction to the sagittal plane and parallel to the posterior surface of the clavicle, at 1.3 cm posterior to the clavisternomastoid angle insures proper puncture of the confluence without anticipated complications.
Adult ; Catheterization ; Catheterization, Central Venous* ; Central Venous Catheters* ; Clavicle ; Humans ; Jugular Veins ; Needles ; Punctures ; Retrospective Studies ; Skin ; Somatotypes ; Subclavian Vein

No abstract available.
Dialysis* ; Humans ; Kidney Failure, Chronic* ; Quality of Life*

No abstract available.
Dialysis* ; Humans ; Kidney Failure, Chronic* ; Quality of Life*

Objective: The purpose of this study was to evaluate the magnetic resonance (MR) characteristics and applicability of new, uniform, extremely small iron-based nanoparticles (ESIONs) with 3–4-nm iron cores using contrast-enhanced magnetic resonance angiography (MRA). Materials and Methods: Seven types of ESIONs were used in phantom and animal experiments with 1.5T, 3T, and 4.7T scanners. The MR characteristics of the ESIONs were evaluated via phantom experiments. With the ESIONs selected by the phantom experiments, animal experiments were performed on eight rabbits. In the animal experiments, the in vivo kinetics and enhancement effect of the ESIONs were evaluated using half-diluted and non-diluted ESIONs. The between-group differences were assessed using a linear mixed model. A commercially available gadolinium-based contrast agent (GBCA) was used as a control. Results: All ESIONs showed a good T1 shortening effect and were applicable for MRA at 1.5T and 3T. The relaxivity ratio of the ESIONs increased with increasing magnetic field strength. In the animal experiments, the ESIONs showed peak signal intensity on the first-pass images and persistent vascular enhancement until 90 minutes. On the 1-week follow-up images, the ESIONs were nearly washed out from the vascular structures and organs. The peak signal intensity on the first-pass images showed no significant difference between the non-diluted ESIONs with 3-mm iron cores and GBCA (p = 1.000). On the 10-minutes post-contrast images, the non-diluted ESIONs showed a significantly higher signal intensity than did the GBCA (p < 0.001). Conclusion In the phantom experiments, the ESIONs with 3–4-nm iron oxide cores showed a good T1 shortening effect at 1.5T and 3T. In the animal experiments, the ESIONs with 3-nm iron cores showed comparable enhancement on the first-pass images and superior enhancement effect on the delayed images compared to the commercially available GBCA at 3T.