CORONARY ARTERY DISEASE
√ Normal origin? (Fig. 1) ⇒ Right coronary artery should arise from the right coronary sinus and left coronary artery from the left coronary sinus (can be hard to assess without ECG-gating).
The left anterior descending artery should originate from the left coronary artery.
- Coronary artery calcifications (Fig. 2)
The amount of coronary artery calcification correlates with coronary artery disease,
one of the leading causes of death worldwide.
CT is highly sensitive for the detection of calcifications,
but only a rough estimation of the severity of coronary artery disease can be made without ECG-gating.
• Coronary artery stent (Fig. 2) - Common procedure for the control of ischemic disease.
They are seen as tubular metal density structures in the coronary artery territory,
almost always associated with beam hardening artifacts.
PERICARDIAL DISEASE
√ Effusion? (Fig. 3) ⇒ measure pericardial space thickness and attenuation values (HU).
There is no direct correlation between the pericardial space thickness and volume of fluid.
If homogeneous and near water attenuation,
consider simple/serous effusion,
if >30 HU,
consider hematic/exsudative effusion.
If very low attenuation,
consider chylopericardium.
√ Thickening? (Fig. 4) ⇒ measure thickness and check for regularity.
The pericardium is considered thickened if it measures > 4 mm.
- Acute - smooth thickening with intense early contrast enhancement,
with variable amount of fluid.
- Chronic - irregular thickening associated with calcification.
- Constrictive - diffuse thickening and/or calcification.
Frequently associated with tubular ventricles (+right) and sigmoid interventricular septum.
Rarely associated with effusion.
- Cardiac Tamponade (Fig. 6) (life-threatening)
Clinical diagnosis supported by imaging findings of large pericardial effusion,
enlargement of the superior/inferior vena cava,
periportal lymphedema and/or reflux of contrast into inferior vena cava/azygos vein.
- Pericardial Cyst (Fig. 7) (mostly incidental)
Round/ovoid,
homogeneous and smooth-marginated mass,
with thin wall,
most commonly arising from the right anterior cardiophrenic angle.
- Pericardial Metastases (Fig. 8)
Occur in ~10% of patients with malignancy,
most frequently from lung carcinoma.
Findings of a irregularly thickened pericardium and/or pericardial nodules support this diagnosis.
A high-attenuation pericardial effusion can be the only sign.
VALVULAR DISEASE
Due to their particular orientation,
valvular evaluation is of limited use in non-gated-CT.
Despite this,
CT is highly sensitive in detecting valvular calcifications; and cardiac chambers dilatation/hypertrophy can be seen as a result of hemodynamic adaptations.
Mitral and aortic valve calcifications are common findings in everyday practice and are associated with stenotic disease.
Valvular insufficiency should be inferred by secondary chamber adaptations.
Non-gated-CT has little sensitivity in detecting valvular vegetations.
However,
in the adequate clinical scenario,
findings of septic embolism can be detected.
MYOCARDIAL DISEASE
- Acute Myocardial Infarction (Fig. 13)
Acute myocardial perfusion defects are seen,
in the arterial phase,
as decreased myocardial enhancement in coronary artery dependent territory.
CT findings related to previous myocardial infarction include subendocardial fatty replacement,
delayed contrast enhancement,
myocardial thinning and calcification in the infarcted area.
- Hypertrophic Cardiomyopathy (Fig. 16)
Hypertrophic cardiomyopathy is one of the leading causes of sudden death in the pediatric age/young adults and is characterized by left ventricle hypertrophy.
Few phenotypes are known,
the most frequent distinguished by a disproportionate enlargement of the interventricular septum compared to the rest of myocardium.
Dilated cardiomyopathy is defined by left ventricular dilation associated with a reduced systolic function.
Many cases are accompanied with intracardiac thrombus.
- Restrictive Cardiomyopathy
Restrictive is the least frequent cardiomyopathy.
CT is not valuable in characterizing this condition whose findings overlap with constrictive pericarditis.
Biatrial enlargement with little ventricular volume change might infer the diagnosis.
INTRACARDIAC MASSES
Thrombi are seen as non-enhancing filling defects,
more frequently identified in the postero-lateral wall of the left atrium or in the left atrial appendage,
but can be found in every cardiac chamber.
Thrombus in the left ventricular apex is associated with previous myocardial infarction.
Cardiac myxoma is the most common primary tumor of the heart,
and the vast majority is discovered in the left atrium,
attached to the interatrial septum.
CT findings of a heterogeneous,
low-attenuating mass are suggestive of myxoma.
Although it is a benign condition,
some complications can be caused by this tumor,
such as valvular obstruction or embolism.
Intracardiac metastases are rare findings (~5 % of cardiac metastases) which may be encountered as multiple nodules/mass,
with soft tissue attenuation and heterogeneous enhancing pattern.
SEPTAL DEFECTS
- Ventricular Septal Defect (Fig. 21)
Common heart defect,
present at birth that allows blood flow from left ventricle to right ventricle (most close spontaneously).
May result in heart failure (dilated right ventricle) and pulmonary hypertension.
Common heart defect,
present at birth that allows communication between both atria.
May result in heart failure,
pulmonary hypertension and arrhythmias.
There are 3 types: ostium secundum (+ frequent; midsepta),
ostium primum (near atrioventricular valves) and sinus venosus (high septum near superior vena cava).
- Lipomatous Hypertrophy of the Inter-atrial Septum (Fig. 23)
Rare disorder distinguished by benign infiltration of the interatrial septum by fat. More prevalent in elderly and/or obese patients.