27 research outputs found
Coronary Artery Fly-Through Using Electron Beam Computed Tomography
BACKGROUND: Virtual reality techniques have recently been introduced into
clinical medicine. This study examines the possibility of coronary artery
fly-through using a dataset obtained by noninvasive coronary angiography
with contrast-enhanced electron-beam computed tomography. METHODS AND
RESULT
In vivo assessment of three dimensional coronary anatomy using electron beam computed tomography after intravenous contrast administration
Intravenous coronary angiography with electron beam computed tomography
(EBCT) allows for the non-invasive visualisation of coronary arteries.
With dedicated computer hardware and software, three dimensional
renderings of the coronary arteries can be constructed, starting from the
individual transaxial tomograms. This article describes image acquisition,
postprocessing techniques, and the results of clinical studies. EBCT
coronary angiography is a promising coronary artery imaging technique.
Currently it is a reasonably robust technique for the visualisation and
assessment of the left main and left anterior descending coronary artery.
The right and circumflex coronary arteries can be visualised less
consistently. Improvements in image acquisition and postprocessing
techniques are expected to improve visualisation and diagnostic accuracy
of the technique
Intravenous coronary angiography by electron beam computed tomography: a clinical evaluation
BACKGROUND:-Noninvasive detection of coronary stenoses with electron beam
CT (EBCT) after intravenous injection of contrast medium has recently
emerged. We sought to determine the diagnostic accuracy of EBCT
angiography in the clinical setting using conventional coronary
angiography as the "gold standard." METHODS AND RESULTS: Thirty-seven
patients (30 men) were investigated. After intravenous injection of 150 mL
of contrast medium, 40 to 60 consecutive transaxial tomograms, covering
the proximal and middle parts of the coronary arteries, were obtained with
ECG triggering at end diastole during breath-holding. Three-dimensional
reconstructions of the proximal and middle parts of the arteries were
compared with the conventional angiograms. Of the 259 proximal and middle
coronary segments, 211 (81%) were analyzable by EBCT. Of the left anterior
descending coronary artery (LAD) segments, 95% were assessable. Right
coronary artery (RCA) and left circumflex artery (LCx) segments were
assessable in 66% and 76%, respectively. Overall sensitivity and
specificity to detect a >50% diameter stenosis were 77% and 94%,
respectively. This was 82% and 92% for the LAD, 60% and 97% for the RCA,
and 83% and 89% for the LCx (all figures based on assessable lesions).
CONCLUSIONS: Intravenous EBCT coronary angiography is a promising coronary
imaging technique. The technique is not yet robust enough to be an
alternative to conventional coronary angiography. It can detect and rule
out significant coronary artery disease of the left main proximal and mid
portions of the LAD with good accuracy
Magnetic resonance imaging of the coronary arteries: clinical results from three dimensional evaluation of a respiratory gated technique
BACKGROUND: Magnetic resonance coronary angiography is challenging because
of the motion of the vessels during cardiac contraction and respiration.
Additional challenges are the small calibre of the arteries and their
complex three dimensional course. Respiratory gating, turboflash
acquisition, and volume rendering techniques may meet the necessary
requirements for appropriate visualisation. OBJECTIVE: To determine the
diagnostic accuracy of respiratory gated magnetic resonance imaging (MRI)
for the detection of significant coronary artery stenoses evaluated with
three dimensional postprocessing software. METHODS: 32 patients referred
for elective coronary angiography were studied with a retrospective
respiratory gated three dimensional gradient echo MRI technique.
Resolution was 1.9 x 1.25 x 2 mm. After manual segmentation three
dimensional evaluation was performed with a volume rendering technique.
RESULTS: Overall 74% (range 50% to 90%) of the proximal and mid coronary
artery segments were visualised with an image quality suitable for further
analysis. Sensitivity and specificity for the detection of significant
stenoses were 50% and 91%, respectively. CONCLUSIONS: Volume rendering of
respiratory gated MRI techniques allows adequate visualisation of the
coronary arteries in patients with a regular breathing pattern.
Significant lesions in the major coronary artery branches can be
identified with a moderate sensitivity and a high specificity
MR coronary angiography with breath-hold targeted volumes: preliminary clinical results
PURPOSE: To assess the clinical value of a magnetic resonance (MR)
coronary angiography strategy involving a small targeted volume to image
one coronary segment in a single breath hold for the detection of greater
than 50% stenosis. MATERIALS AND METHODS: Thirty-eight patients referred
for elective coronary angiography were included. The coronary arteries
were localized during single-breath-hold, three-dimensional imaging of the
entire heart. MR coronary angiography was then performed along the major
coronary branches with a double-oblique, three-dimensional, gradient-echo
sequence. Conventional coronary angiography was the reference-standard
method. RESULTS: Adequate visualization was achieved with MR coronary
angiography in 85%-91% of the proximal coronary arterial branches and in
38%-76% of the middle and distal branches. Overall, 187 (69%) of 272
segments were suitable for comparison between conventional and MR coronary
angiography. The diagnostic accuracy of MR coronary angiography for the
detection of hemodynamically significant stenoses was 92%; sensitivity,
68%; and specificity, 97%. The sensitivity in individual segments was
50%-77%, whereas the specificity was 94%-100%. CONCLUSION: Adequate
visualization of the major coronary arterial branches was possible in the
majority of patients. The observed accuracy of MR coronary angiography for
detection of hemodynamically significant coronary arterial stenosis is
promising, but it needs to be higher before this modality can be used
reliably in a clinical setting