Arterial Plaque Evaluation Using OCT: A comparison …Kawasaki Medical School Angioplasty summit 2005Angioplasty summit 2005 Takashi Akasaka, MD Kawasaki Medical School Takashi Akasaka,

Kawasaki Medical SchoolKawasaki Medical School

Angioplasty summit 2005Angioplasty summit 2005

Takashi Akasaka, MDKawasaki Medical School

Takashi Akasaka, MDKawasaki Medical School

Arterial Plaque Evaluation Using OCT:A comparison with IVUS and histological findings

Arterial Plaque Evaluation Using OCT:A comparison with IVUS and histological findings


OCT vs histology

OCTOCT

HistologyHistology


OCT Engine

Rotarycoupler

Laptop PC

OCT system ( LightLab prototype )OCT system ( LightLab prototype )ImageWire®


PurposePurpose

To compare coronary vessel wall structural images

obtained by OCT and IVUS with histological findings

To compare coronary vessel wall structural images

obtained by OCT and IVUS with histological findings


166 coronary lesions (28 autopsy cases）166 coronary lesions (28 autopsy cases）

SubjectsSubjects

Age 72±6 y.o. ( Male / Female: 16 / 12）Age 72±6 y.o. ( Male / Female: 16 / 12）

OMI 1OMI 1AMI 2AMI 2Pulmonary embolism 2Pulmonary embolism 2Liver chirrosis 3Liver chirrosis 3Pneumonia 4Pneumonia 4Leukemia 6Leukemia 6carcinoma 7carcinoma 7Others 3Others 3


Methods 1Methods 1

Comparison between OCT & IVUS images with histology in 166 coronary lesions

Comparison between OCT & IVUS images with histology in 166 coronary lesions

OCT & IVUS recordings（３７℃ PBS solution, 80mmHg）OCT & IVUS recordings（３７℃ PBS solution, 80mmHg）

HE ・Masson-trichrome ・Elastica-van Gieson stainsHE ・Masson-trichrome ・Elastica-van Gieson stains

Pressure perfusion-fixed in 10% formalin (48 hours)Pressure perfusion-fixed in 10% formalin (48 hours)

Paraffin embedding4 μm thickness cut sections every 400 μm

Paraffin embedding4 μm thickness cut sections every 400 μm


syringomanometersyringomanometer

PBS (37℃）

Coronary artery

PBS(37℃)

Methods 2Methods 2

IVUS：Atlantis SR ProⓇ 2.5Fr. 40MHz, Boston-Scientifics Ltd.

OCT ：ImageWireTM, LightLab Imaging, Westford.

IVUS：Atlantis SR ProⓇ 2.5Fr. 40MHz, Boston-Scientifics Ltd.

OCT ：ImageWireTM, LightLab Imaging, Westford.

Pressure inside the coronary artery was maintained at 80 mmHg

Pressure inside the coronary artery was maintained at 80 mmHg

* Serial images of OCT and IVUS were obtained using an automatic pullback device.


OCT IVUSHistologyHistology(HE) (Masson)(EVG)

Every 400 μm Every 400 μm


Fibrous plaqueFibrous plaque

Homogenous

Signal-richHigh-echoic


Fibrous plaque

100μm

1mm

High-echoicHigh-echoic

AttenuationAttenuation

Signal-richSignal-richHomogenousHomogenous


Fibrocalcific plaqueFibrocalcific plaque

1mm

100μm

EcholucentEcholucent

ShadowingShadowingHigh-echoicHigh-echoic

Sharp bordersSharp borders


Lipid-rich plaqueLipid-rich plaque

1mm



Diffuse bordersDiffuse borders


Fibro-lipidic plaqueFibro-lipidic plaque

EcholucentEcholucentPartially

echolucentPartially

echolucentDiffuse bordersDiffuse borders

within signal-rich

homogenus

within signal-rich

homogenus


85 94 83 95

OCT image Fibrous (n=43) Fibrocalcific (n=82) Lipid (n=41)

IVUS imageFibrous (n=43) Fibrocalcific (n=82)Lipid (n=41)

OCT image Fibrous (n=43) Fibrocalcific (n=82) Lipid (n=41)

IVUS imageFibrous (n=43) Fibrocalcific (n=82)Lipid (n=41)

HIstopathologic Diagnosis Positive Negative

Sensitivity Specificity Predictive Value Predictive Value

Data are percentages. * p < 0.05 vs. OCT image.Data are percentages. * p < 0.05 vs. OCT image.

79 99 97 9379 99 97 9396 88 89 9696 88 89 96

88 86 69 9588 86 69 95

98 96 96 9898 96 96 9859 97 86 87*

Comparison between OCT and IVUS with histologyComparison between OCT and IVUS with histology


Summary 1Summary 1

1. Fibrous plaques were observed as homogenoussignal-rich findings.

1. Fibrous plaques were observed as homogenoussignal-rich findings.

2. Calcific plaques were recorded as echo-lucent images with sharp borders.

2. Calcific plaques were recorded as echo-lucent images with sharp borders.

3. Lipid rich plaques were demonstrated as echo-lucent images with diffuse borders.

3. Lipid rich plaques were demonstrated as echo-lucent images with diffuse borders.

OCT findings of plaque morphologyOCT findings of plaque morphology


Ｔhrombus

White thrombusRed thrombus


Thin fibrous cap (vulnerable plaque)Thin fibrous cap (vulnerable plaque)OCT IVUS

HE


IMT (OCT vs IVUS)

intimaintimaintima-media complexintima-media complexadventitia adventitia

mediamedia

adventitia adventitia


Intima-Media Complex Thickness ( IMT ) Histology vs IVUS

Intima-Media Complex Thickness ( IMT ) Histology vs IVUS

His

tolo

gy –

IVU

S (m

m)

His

tolo

gy –

IVU

S (m

m)

Histology (mm)Histology (mm)

IVU

S (m

m)

IVU

S (m

m) +2SD+2SD

-2SD-2SD

Average IMT (mm)Average IMT (mm)0.10.1 0.40.4 0.70.7 1.01.0 1.31.3

-0.2-0.2-0.1-0.1

00

0.20.20.30.3

0.10.1

-0.3-0.3p<0.001p<0.001

0.40.4

0.80.8

1.21.2

0.60.6

1.01.0

0.20.2

0.20.2 0.40.4 0.60.6 0.80.8 1.01.0 1.21.2 1.41.40.00.00.00.0

r = 0.878r = 0.878


Intima-Media Complex Thickness ( IMT ) Histology vs OCT

Intima-Media Complex Thickness ( IMT ) Histology vs OCT

His

tolo

gy –

OC

T (m

m)

His

tolo

gy –

OC

T (m

m)

Average (mm)Average (mm)

+2SD+2SD

-2SD-2SD-0.2-0.2-0.1-0.1

00

0.20.20.30.3

0.10.1

-0.3-0.3

0.10.1 0.40.4 0.70.7 1.01.0 1.31.3

Histology (mm)Histology (mm)

OC

T (m

m)

OC

T (m

m)

p <0.001p <0.0010.40.4

0.80.8

1.21.2

0.60.6

1.01.0

0.20.2

0.20.2 0.40.4 0.60.6 0.80.8 1.01.0 1.21.2 1.41.40.00.0

0.00.0

r = 0.946r = 0.946


Summary 2Summary 2

1. Lumen area and diameter could be measuredcorrectly by OCT as those measured by IVUS.

1. Lumen area and diameter could be measuredcorrectly by OCT as those measured by IVUS.

2. OCT could identify three layers of the coronaryartery wall clearly compared with IVUS.

2. OCT could identify three layers of the coronaryartery wall clearly compared with IVUS.

3. Thickness of intima-media complexes could be measured more accurately by OCT compared with IVUS.

3. Thickness of intima-media complexes could be measured more accurately by OCT compared with IVUS.


OCT findings

CD68(macrophage)

CD68(macrophage)

OCTOCT


Endothel

CollagenCollagenAgarAgar

EndothelEndothel


Endothel


Endothel (＋)

OCT catheter

Endothel ?

Lab. dish



Endothel (－)

OCT catheter

Lab. dish



Macrophages


Collagen・Ox-LDL gelCollagen・Ox-LDL gel

EndothelEndothel

RBCRBCMonocyteMonocyteSerumSerum

BloodBlood

MonocyteMonocyte

Foam cellFoam cell

Culture for a few weeksCulture for a few weeks

Culture for a few daysCulture for a few days


Histological findingsHistological findings

Infiltration of monocytes to collagen gel layer

500μm

Collagen-gell layerCollagen-gell layer


Histrogical findingsHistrogical findings

Foam cell formations of monocytes by phagocytosisof Ox-LDL can be observed in the collagen gel layer 3 weeks after cell culture as demonstrated below.

Foam cell formations of monocytes by phagocytosisof Ox-LDL can be observed in the collagen gel layer 3 weeks after cell culture as demonstrated below.


OCT findings

BeforeBefore

1 week later1 week later

3 weeks later3 weeks later


Summary 3Summary 3

3. OCT may have a possibility to identify the accumulation of macrophages within the fibrous cap of vulnerable plaques as the different light reflections.

3. OCT may have a possibility to identify the accumulation of macrophages within the fibrous cap of vulnerable plaques as the different light reflections.

1. OCT could identify the different tissues by the reflections between the layer of the different tissue components.

1. OCT could identify the different tissues by the reflections between the layer of the different tissue components.

2. Endothelial cell could not be demonstrated by OCT directly.

2. Endothelial cell could not be demonstrated by OCT directly.


ConclusionsConclusions

1. OCT may allow us to identify tissue characterization more accurately than IVUS.

1. OCT may allow us to identify tissue characterization more accurately than IVUS.

2. OCT might have a limitation in the depth of beam penetration.

2. OCT might have a limitation in the depth of beam penetration.

3. OCT may have a possibility to identify vulnerable plaques by the findings of the accumulation of macrophages within the fibrous cap.

3. OCT may have a possibility to identify vulnerable plaques by the findings of the accumulation of macrophages within the fibrous cap.


Thank you for your attention !!Thank you for your attention !!



Superficial calcificationSuperficial calcification

EcholucentEcholucentShadowingShadowingHigh-echoicHigh-echoic

Sharp bordersSharp borders

Documents

Arterial Plaque Evaluation Using OCT: A comparison …Kawasaki Medical School Angioplasty summit 2005Angioplasty summit 2005 Takashi Akasaka, MD Kawasaki Medical School Takashi Akasaka,