A simple and efficient methodology to improve geometric accuracy in gamma knife radiation surgery: implementation in multiple brain metastases.

Purpose: To propose, verify, and implement a simple and efficient methodology for the improvement of total geometric accuracy in multiple brain metastases gamma knife (GK) radiation surgery.

Methods And Materials: The proposed methodology exploits the directional dependence of magnetic resonance imaging (MRI)-related spatial distortions stemming from background field inhomogeneities, also known as sequence-dependent distortions, with respect to the read-gradient polarity during MRI acquisition. First, an extra MRI pulse sequence is acquired with the same imaging parameters as those used for routine patient imaging, aside from a reversal in the read-gradient polarity.

Imaging of coronary artery bypass grafts by computed tomography coronary angiography.

In recent years, computed tomography coronary angiography is commonly performed as a follow-up examination after coronary artery bypass graft surgery. Coronary grafts owing to their minimal motion are well visualized by computed tomography coronary angiography, allowing radiologists to assess their patency noninvasively with very high diagnostic accuracy. The purpose of this pictorial essay is to provide an excellent overview of the anatomy and findings concerning coronary artery bypass grafts.

Coronary artery anomalies in adults: imaging at dual source CT coronary angiography.

Congenital abnormalities of the coronary arteries have an incidence of 1%, and most of these are benign. However, a small number are associated with myocardial ischaemia and sudden death. Various imaging modalities are available for coronary artery assessment.

Correlation of radiation dose and heart rate in dual-source computed tomography coronary angiography.

Background: Computed tomography coronary angiography (CTCA) has been widely used since the introduction of 64-slice scanners and dual-source CT technology, but the relatively high radiation dose remains a major concern.

Purpose: To evaluate the relationship between radiation exposure and heart rate (HR), in dual-source CTCA.

Material And Methods: Data from 218 CTCA examinations, performed with a dual-source 64-slices scanner, were statistically evaluated.

Cardiac magnetic resonance detection and typical appearance of microvascular obstruction following myocardial infarction.

We report the case of a 58-year-old man with a recent anterior myocardial infarction, for which he did not receive prompt reperfusion therapy. The patient underwent cardiac magnetic resonance (CMR) imaging, for the assessment of left ventricular function and myocardial viability, and coronary angiography, two weeks after the acute cardiac event. The CMR study demonstrated a moderately dilated left ventricle, with impaired systolic function and wall motion abnormalities in the anterior, apical and inferior left ventricular walls.

Relationship of number of phases per cardiac cycle and accuracy of measurement of left ventricular volumes, ejection fraction, and mass.

In cine cardiac magnetic resonance imaging (MRI) studies, for any preset imaging parameters the number of phases per cardiac cycle for a single slice is proportional to breath-hold duration. We investigated the relationship between the accuracy of measurement of left ventricular (LV) end-diastolic and end-systolic volumes (EDV and ESV, respectively), mass and ejection fraction (EF), and the number of phases acquired per cardiac cycle. Twelve adult volunteers underwent cardiac MRI and five complete LV functional studies were obtained with 8, 11, 14, 17, and 20 phases per cardiac cycle.

Diagnostic performance of coronary magnetic resonance angiography as compared against conventional X-ray angiography: a meta-analysis.

Objectives: This study was designed to define the current role of coronary magnetic resonance angiography (CMRA) for the diagnosis of coronary artery disease (CAD).

Background: Coronary magnetic resonance angiography has been proposed as a promising noninvasive method for diagnosis of CAD, but individual studies evaluating its clinical value have been of limited sample size.

Methods: We identified all studies (MEDLINE and EMBASE) that evaluated CAD by both CMRA and conventional angiography in >/=10 subjects during the period 1991 to January 2004.