Transcript Quantitative and Qualitative Image Comparison Between

Quantitative and Qualitative Image Comparison Between Intravascular Ultrasound and
Optical Coherence Tomography
Nicholas J. Miele, Olivia Manfrini, Barry L. Sharaf, Edward McNamara, Lynne L. Johnson, David O. Williams
Rhode Island Hospital, Providence, RI; Brown University Medical School, Providence, RI
Aims
Results
Results
The aim of this study was to compare quantitatively and
qualitatively in vivo images obtained by OCT to those of IVUS.
Image Comparisons
Comparison Between IVUS and OCT Measurement of
External Elastic Membrane (EEM)
Background: Optical coherence tomography (OCT) represents
a promising new technology for intracoronary imaging. The
aim of this study was to compare OCT to intravascular
ultrasound (IVUS) imaging in vivo porcine coronary arteries.
Methods: A new retro-flush OCT catheter was used to obtain
images. A 50% contrast and 50% lactated ringers solution was
injected to remove blood from the field of view. Both OCT
and IVUS pictures were obtained with digital acquisition
systems. We compared 13 images: 2 left main coronary artery,
5 left anterior descending artery (LAD), 2 diagonal, and 4
right coronary artery). For each image run multiple
measurements and qualitative analysis were performed.
Results: Imaging runs with the retro-flush catheter were
similar in duration to those from IVUS. Both cross-sectional
and longitudinal views were obtained. Both devices tracked
the guide wire easily. 26 paired measurements of external
elastic membrane diameter were compared between IVUS and
OCT. There were no differences between IVUS 3.31mm ±
0.68mm and OCT 3.46mm ± 0.75mm, p = 0.48. Layers of the
arterial wall were more distinguishable with OCT than with
IVUS. OCT allowed for better localization of the side branch
origin as well as better visualization of the distal arterial
features. Additionally, peri-arterial venous structures not seen
with IVUS were identifiable by OCT. An induced wire
dissection was not detected by IVUS but was readily
identifiable by OCT. There were no complications with either
the IVUS or OCT imaging acquisition. Conclusions: OCT
provided comparable quantitative image measurements with
IVUS but defined qualitative vessel features more precisely.
Background
Optical Coherence Tomography (OCT) is a new modality
for high-resolution, cross-sectional intravascular imaging.
OCT utilizes near-infrared light instead of ultrasound to
capture images of the vessel structures. Image resolution is
at least one order of magnitude higher than that of
Intravascular Ultrasound (IVUS), allowing for a more
detailed analysis of the arterial features. Inability to image
through a blood signal, however, is a potential limitation.
While there are many published studies regarding OCT,
little data exists on in vivo coronary imaging and no
comparative information is available.
Methods
Two separate swine models (3 normal, 2 balloon injury / lard
fed) (n=5) were used to compare intracoronary images
obtained by both IVUS and OCT (Fig. A.). Images runs were
begun in the same vessel location (3 left main, 7 left anterior
descending, 2 diagonal, 3 left circumflex, and 6 right coronary
arteries) for both devices, for a total of 128 paired
measurements. Angiographic features such as side branches
and lesion characteristics were used as landmarks for catheter
positioning and measurements of vessel size. Both systems
utilized automated pullbacks at 0.5mm per second.
Quantitative measurements, pullback duration, and tolerance to
the device were compared between the two systems. Two
different types of OCT catheters were used for the imaging
wire: 1) a retro-flush system (50%/50% lactated
ringers(LR)/contrast in animal # 1, 100% LR subsequently) in
the first three animals; and 2) a Toaki occlusion balloon
catheter (also accompanied by a LR flush) in the last two
(Figs. B. & C.).
A.
Coronary Dissection
IVUS
OCT
4.8
4.6
4.4
4.2
IVUS EEM
Abstract
4.0
3.8
3.6
3.4
3.2
Peri-Arterial Venous Structures
IVUS
OCT
3.0
2.8
3.0
3.2
3.4
3.6
3.8 4.0 4.2 4.4 4.6 4.8
5
OCT EEM
Y = .207 + .925 * X; R2 = .868; p < 0.0001
There was no difference in mean EEM OCT (3.94 ± 0.47mm) vs. IVUS
(3.85 ± 0.47mm)(p=0.428).
During imaging runs there were no differences in the prevalence or degree
of ischemia with either device.
B.
There were no differences in either image quality, imaging times, or
quantitative measurements between the two OCT catheter systems.
Computer
There were no difference in duration of pullback times between OCT (mean
35.4 ± 1.1 sec.) vs. IVUS (mean 43.6 ± 2.5 sec.) (p = 0.10)
1 mm
Quantitative Comparison
Patient
Interface
Unit
IVUS
C.
3.57
OCT
3.72
There was a significant difference in reproducibility between OCT and
IVUS. Variability was less with OCT, 0.01mm vs. 0.03mm, p = 0.015;
Coefficient of Variation 0.29% vs. 0.85%.
Conclusions
1. Values of EEM were similar between OCT and IVUS.
Optical
Engine
A. LightLab OCT System
B. Retro-flush Imaging Catheter
with internal imaging wire
C. Imaging wire delivered
through Toaki balloon catheter
2. Qualitative features were more clearly identified and defined by OCT and
similar between the two catheter systems.
3. Image acquisition was not limited by the development of ischemia.
4. There was less variability in repeated measurements of OCT compared
with those of IVUS.