MDCT COMPLEMENTARY TO CORONARY ANGIOGRAPHY

Radiology departement

La rabta hospital

INTRODUCTION• The possibility to perform cardiac and coronary imaging was a major

driving force behind an ongoing, rapid evolution of scanner technology,

accompanied by improvements of software and post-processing tools.

• The most recent generations of MDCT with the ability to acquire 64 slices

simultaneously allow relatively robust morphological and functional

imaging of the heart.

• Although initially, clinical applications were restricted to the detection of

coronary calcium, visualization of the coronary artery lumen (non-invasive

coronary angiography) has now become the major focus of cardiac MDCT.

PATIENTS AND METHODS• Analytical descriptive and prospective study about

37 patients who subsequently received a computed tomographic

coronary angiography in addition to exploration with coronary

angiography when it could not be formally conclusive.

=> The results and limitations of MDCT were evaluated according to

different clinical and anatomical situations.

• Patients explored with usual MDCT coronary angiography technique.

• Use of beta blockers when heart rate above 65 b / min

RESULTS1. DEMOGRAPHIC AND CLINICAL DATA:

• The average age of our patients was 60,1 years, from to years.

• There were women and men with sex ratio 2.7/1.

INDICATIONS OF CORONARY ANGIOGRAPHY:

• Coronary angiography was performed after an acute coronary syndrome or

chest pain 91% of cases.

• 2 patients were admitted to investigate a dilated cardiomyopathy (n =2).

• One patient was admitted for congestive heart failure revealing an aortic

coarctation associated with an atrial septal defect

MDCT INDICATIONS:

• Further study of congenital anomalies of the coronary arteries (n=7).

• Not visualized coronary artery bypass grafts (n=11).

• Exploration of ostial coronary lesions (n = 14).

• Not catheterized coronary (n = 2).

2. STUDY OF CONGENITAL ANOMALIES OF THE CORONARY

ARTERIES

• 7 patients.

• Indications were:

• Further study of the origin or path of an abnormal origin

of a coronary artery from the contralateral sinus of

Valsalva side.(n=)

• Suspicion of a single coronary artery(n=)

• Exploration of a coronary – pulmonary fistula (n=)

IVA arising from right anterior sinus. incidence in cranial and anterior right oblique, note the recovery of right coronary system

Coronary angiography:ooccluded right coronary artery from its origin back through the network contralateral side.oleft anterior descending arising from right anterior sinus.

The data of coronary angiography could not formally identify the pre, retro or inter aorto pulmonary course

• 48 years old man • Having already received a right coronary stenting.• Currently admitted for a recurrence of chest pain on optimal medical

therapy.

Case 1

3D MDCT reconstructions (left), volume rendering mode and 2D curvilinear (right): The IVA artery arises from the segment I of the right coronary artery, describing a inter aorto-pulmonary course before being in the inter-ventricular furrow.

The patient underwent a multidetector CT which confirmed the presence of an abnormal origin of the left anterior artery arising from the right coronary artery, with inter aortopulmonary course.

Case 2

Coronary angiography: left profile, right coronary dominant giving PDA which seems to extend through an LAD

• Female, 55 years old, diabetic, hypertensive and obese.• Admitted to explore a dilated cardiomyopathy.Coronary angiography failed to opacify the left coronary system, but described a large dominant right coronary artery with a posterior descending artery giving back into a semblance left anterior descending.

Reconstruction 3D Volume rendering: Lack of individualization of a left coronary artery, the coronary system can be summarized in a single large right coronary artery.

The MDCT revealed: The right coronary artery gives an PDA repeating in part the territory of the LADReverse left ventricular territory includes part of the marginal=> Confirming the fact whether a single coronary artery

Case 3

Coronary angiography: catheterization of the left coronary shows the arising of a vessel from the common core that seems to irrigate an undetermined structure.

• Man aged 32, Type I diabetic, and hypothyroid,• Admitted for exploration of dilated cardiomyopathy.

Coronary angiography:o has not objectified atheromatous lesion.oaffirmed the existence of an artery emerging from a common core with undetermined irrigation

MDCT in axial and sagittal reconstruction. The vessel described above comes into contact with the anterior trunk of the left pulmonary artery with evidence of passage of contrast in the pulmonary artery, confirming coronary pulmonary fistula

• The CT scan examination was performed with biphasic injection of contrast whose goal is to get on the acquisition of a significant enhancement in the left cavities contrasting with little opacified right cavities.

• This biphasic injection helped to reveal the coronary pulmonary fistula.

3. CORONARY ARTERY BYPASS GRAFTS:

• 11 coronary patients, having already undergone coronary artery bypass

grafting

• 10 men and one woman.

• Average age of 63.5 years

• These patients accounted for 26 bridges to analyze which types were:

o Saphenous vein grafts in 14 cases

o Internal mammary graft in 10 cases

o Radial graft in 2 cases.

• The anastomoses were on:

o LAD in 9 cases

o the marginal artery in 9 cases

o the diagonal artery in 4 cases

o the right coronary artery in 6 cases

CORONAY ANGIOGRAPHY DATA:

• 6 of 10 internal mammary grafts were patent, four were not

opacified.

• 6 of 15 venous grafts were patent, the grafts were not opacified in

eight cases, one was thrombosed.

• The two radial graftss were not opacified.

MDCT DATA:

• All not opacified grafts were studied on CT :

• the four non-opacified internal mammary grafts:

o 2 were patent.

o one was thrombosed.

o One was analyzed only in part, the distal anastomosis could not be

studied because of the occurrence of tachycardia.

the 8 non-opacified venous grafts:

o 5 were thrombosed

o two were patent

o one was the site of a distal anastomotic stricture

o The two radial graftss were occluded.

• For segments opacified by both methods, the

findings of the scanner were identical to those of

coronary angiography.

• Functional grafts studied with coronary

angiography were also permeable on CT.

coronary angiography: Graft ISV/2 nd diagonal permeable and of good size ISV / 1 st lateral permeable good caliber The bypass LIMA / LAD was impossible to opacify.

• Man, 63 years old, smoking and diabetes• Background:• double angioplasty of the circumflex and right coronary six years earlier• then triple coronary artery bypass grafting LAD/LIMA Second-diagonal /ISV First-Side / ISV• This patient was admitted for treatment of chest pain

Case 4

• Coronary Computed tomography described

• A graft on the left internal mammary /LAD

permeable.

• The analysis of the rest of the thoracic led

to the discovery of a highly suspicious apical

left mass without associated signs of

mediastinal extension.

4. EXPLORATION OF OSTIAL CORONARY LESIONS :

• 14 patients with mean age of 57.75 years (41-74 years).

• / patients were investigated after a confirmed acute coronary syndrom

or suspected chest pain.

• X patient has been explored in the context of dilated cardiomyopathy.

• The ostial lesions:

o Lesions of the left main trunk (n = )

o Ostial lesion of the right coronary (n = )

o Ostial stenosis of the LAD

• Computed tomography coronary helped give a useful answer to the

diagnostic management and / or therapeutic clinical situations in /14

• The ostial lesions:

o Lesions of the left main trunk (n = )

o Ostial lesion of the right coronary (n = )

o Ostial stenosis of the LAD

• Computed tomography coronary helped give a

useful answer to the diagnostic management and /

or therapeutic clinical situations in /14

Case 5

caudal LAO coronary incidence. : Ostial stenosis of the left coronary artery, difficult to quantify

• Male 65 years old, smoking hypertension, diabetes• Admitted for acute coronary syndromes without ST segment above.• The ECG and ultrasound trans chest were unremarkable.Coronary angiography was suspected without affirming, ostial stenosis of the left coronary artery.The LAD was infiltrated without significant stenosis and right coronary artery was small and dominated.

MDCT-Reconstruction curvilinear and cross section for measuring the flatness of the core and confirming the closeness of the stenosis. Stenosis hypodense non-calcified plaque.

• Computed tomography of the coronary arteries showed: the presence of a hypodense ostial plaque in left coronary trunk responsible for stenosis with a minimum area of 3.6 mm2 to planimetry.This patient underwent a double bypass of the LAD by the left internal mammary artery and lateral saphenous vein.

Case 6

Coronary angiography: left anterior oblique Incidence showing a calcified ostial stenosis of the right coronary artery

• Patient aged 59 years, smoking• Admitted for acute coronary syndrome.

Coronary angiography has described a right coronary ostial calcified stenosis whose severity is poorly quantified, the rest of the tree was healthy.

Coronary MDCT: 3D MIP and curvilinear reconstruction of the right coronary artery: partially calcified ostial plaque responsible for a sub-occlusive stenosis

The MDCT confirmed the presence of a large eccentric calcified plaque in right coronary ostial responsible for a severe stenosis.

5. NOT CATHETERIZED CORONARY :

• 60 years old female patient, hypertensive since 30 years.

• Admitted for congestive heart failure revealing a tight aortic

coarctation associated with atrial septal defect (veinosus

sinus).

• Preoperative coronary angiography through the radial

approach could not be achieved, for failure to advance the

probe of the ascending aorta due to a strong collaterally with

tortuosity of the brachiocephalic trunk.

• The MDCTA :

o confirmed coarctation of the aorta.

o studied the collateral circulation.

o studied the coronary system which was free of lesions.

CT angiography: sagittal reconstruction : isthmic coarctation of the aorta

DISCUSSION• Recent technological developments have enabled the

cardiac CT to fit into the diagnostic of coronary disease.

• Coronary angiography remains the standard protocol in

acute coronary syndromes with electrical and / or

enzymatic modifications, and symptomatic patients with

high likelihood of coronary disease.

• The detection of coronary artery disease is the main

indication of cardiac CT retained due to its negative

predictive value close to 100%

ADVANTAGES AND LIMITATION OF MDCT

ADVANTAGES:

• The introduction of multi-detector row computed tomography

(MDCT) led to a significant improvement in the temporal and

spatial resolution of CT, which permitted substantial expansion of

potential indications for CT imaging. Small and rapidly moving

anatomic structures could be visualized with good image quality.

• Coronary CT angiography investigation allows for the accurate

detection of coronary artery stenoses. Especially, the negative

predictive value has uniformly been found to be high, indicating

that the technique may be most suitable as a non-invasive tool

to rule out the presence of obstructive coronary lesions.

• 3D imaging provides a real coronary mapping mode using the

3D volume rendering and MIP.

• CT allows by the measurement of density, to distinguish plaques

with high lipid component called vulnerable, with high risk of

erosion.

• Besides the detection of coronary stenoses, cardiac CT has the

potential to visualize earlier stages of coronary atherosclerosis

• Besides the assessment of the coronary arteries, CT provides for

accurate assessment of general cardiac morphology.

• This can be particularly useful in the context of electrophysiology

when detailed anatomic information (e.g. the pulmonary veins

and left atrium prior to ablation procedures or coronary veins in

CRT for left ventricular lead placement) is needed.

• Similarly, CT imaging can be useful in patients

with congenital heart disease or other structural

cardiac disease.

• Exploration concomitant lung parenchyma;

according to Haller, 5% of coronary CT

examinations are an opportunity to discover an

extracardiac disease (lung cancer, pulmonary

embolism, benign mass, pneumonia)

LIMITATIONS:

• Several situations currently pose challenges for reliable CT imaging

these include

• The patient should be cooperative , able to do a few seconds apnea,

to withstand the supine position for ten minutes, arms above the

head

• patients with arrhythmias,

• patients with advanced CAD and pronounced coronary calcifications,

• and patients with coronary artery stents, which are often difficult to

evaluate. Similarly, although CABGs can be assessed with very high

diagnostic accuracy, detection of stenoses at the site of anastomosis

and in the native coronary arteries of patients after CABG has

reduced accuracy.

• Coronary CT angiography is not routinely recommendable in these

situations.

• Patients with coronary artery stents, which are often difficult to

evaluate. Similarly, although CABGs can be assessed with very high

diagnostic accuracy, detection of stenoses at the site of anastomosis

and in the native coronary arteries of patients after CABG has

reduced accuracy.

• Obesity is a factor of degradation of the quality of the examination

due to the attenuation of X-ray

• One limitation technique is the spatial resolution is lower than that of

conventional angiography makes the exploration of the distal (septal,

diagonal, marginal) difficult.

RISKS OF MDCT

• The usual risks of the injection of iodinated contrast agents (allergic

risk, renal failure)

• The X-ray dose delivered remains significant.

• A coronary MDCT strips is currently two times more radiant than

coronary angiography although the values recorded are well below

accepted standards.

STUDY OF CONGENITAL OF THE CORONARY ARTERIES ANOMALIES

• Although coronary anomalies are rare conditions, possible

consequences include myocardial infarction and sudden death.

• The identification of the origin and course of aberrant coronary

arteries by invasive angiography can be difficult. Because of

the three-dimensional nature of the data set, MDCT is very well

suited to detect and define the anatomic course of coronary

artery anomalies and their relationship to other cardiac and

non-cardiac structures

• Numerous case reports and several research papers have

demonstrated that the CT analysis of coronary anatomy in

these patients is straightforward and very reliable with an

accuracy close to 100%.

=>The robust visualization and classification of anomalous

coronary arteries make CT angiography a first-choice imaging

modality for the investigation of known or suspected coronary

artery anomalies. Radiation dose must be considered often in

the young patients, and measures to keep dose as low as

possible must be employed.

• In our series, angiography and multidetector CT were

complementary.

• In fact, coronary angiography was performed to explore an

acute coronary syndrome whereas CT coronary was

requested further study of the origin or path of an abnormal

origin of from a coronary sinus of Valsalva in contralateral

side.

MDCT ON COMPLEX CORONARY-PULMONARY ARTERY

FISTULA

• Coronary-pulmonary artery fistula is usually detected in 0.1%

to 0.2% of coronary angiograms .

• Although not all coronary-pulmonary artery fistulas are

clinically or hemodynamically significant, some can result in

serious consequences including myocardial ischemia,

myocardial infarction, or sudden death.

• When complex anatomy or intervention is contemplated,

coronary angiography may not be sufficient. An ideal

investigation technique should be noninvasive and provide a

quality anatomic description of the fistula.

• The diagnostic value of coronary angiography is limited by its

planar imaging nature, restricted angle of angiographic

projections, and concern for the contrast load.

• The 3D reconstruction with viewing at an unlimited angle

allows:

o to demonstrate a lesion such as a fistula at its best projection

o without subjecting the patient to repeated radiation exposure

and an additional contrast load.

o makes assessment of the size and exact location of the lesion

feasible.

o quantitative cardiac function analysis.

• This could be helpful for planning future cardiovascular

intervention.

CORONARY ARTERY BYPASS GRAFTS

• Coronary artery bypass grafts (CABGs) move less rapidly and

particularly venous grafts have relatively large diameters

compared with native coronary arteries .

• Occluded grafts and stenoses in the body of bypass conduits

can therefore be detected with very high diagnostic accuracy.

• Accurate assessment of the native coronary arteries by

cardiac CT in patients after CABG is often challenging and

image quality impaired because of advanced CAD and

pronounced coronary calcifications.

• Consequently, the studies that have investigated the

accuracy of CT angiography to evaluate the native arteries in

patients with bypass grafts have reported low accuracies.

• The possibility of a 3-dimensional volumetric study allows easy

viewing of the path of bridges in MDCT , this is crucial before

any redux surgery.

• => Although the clinical application of CT angiography may be

useful in very selected patients in whom only bypass graft

assessment is necessary (e.g. failed visualization of a graft in

invasive angiography), the inability to reliably visualize the

native coronary arteries in patients post-CABG poses severe

restrictions to the general use of CT angiography in post-

bypass patients.

EXPLORATION OF OSTIAL CORONARY LESIONS

• The exploration of the ostium and the first centimeter

of the arteries on coronary angiography is sometimes

delicate. Ostial stenosis may be overlooked, often

hidden or difficult to identify.

• Luminographie planimetry of the core curriculum is

accessible to the scanner.

• Caussin, reports that the 64 slice CT has a sensitivity

and specificity of 87% and 72% in the diagnosis of

significant stenoses of the core compared to IVUS.

• Several authors have also reported the interest of the

scanner in the evaluation of ostial stenosis of the right

coronary.

• The MDCT is as a complementary tool in

the exploration of coronary ostial stenosis

of the core and the right coronary artery.

• It confirms and quantifies stenosis, precise

topography, approach the nature of the

plaque and guide therapeutic decisions.

NOT CATHETERIZED CORONARY

• The noninvasive nature of CT

coronary imaging has allowed a

coronary artery exploration when it is

technically impossible by coronary

angiography.

CONCLUSION

• Although coronary angiography remains the

gold standard investigation for the evaluation of

suspected coronary artery disease. Newer, less

invasive, modalities have been developed that

may complement this. CT coronary angiography

offers high sensitivity and specificity in the

identification of coronary lesions.