CT - Chapter 8 Flashcards
How can a myocardial perfusion defect be differentiated from an artifact?
- True perfusion defect will:
- persist throughout multiple, different phases of the cardiac cycle
- visualized in both systole and diastole
Which are the best window width and window level for assessing myocardial perfusion defects, respectively?
WW: 200 / WL: 100
- subtle differences need to be displayed
- narrow window width and window level similar to the normal myocardial attenuation will improve visualization o f perfusion defects as compared to normal myocardium
Which coronary artery distribution is affected by the perfusion defect displayed in the image?
LCx or RCA (depending on dominance)
- perfusion defect involving the inferior, inferoseptal and inferolateral walls
Describe the finding:
Microvascular obstruction
- CT findings:
- delayed enhancement CT image (10 minutes after contrast injection)
- apparent due to hyperenhancement of parts of the otherwise dark myocardium
- Previous MI
- surrounding delayed hyperenhacement –> myocardial necrosis
- inner dark area + outer bright area –> total infarct size
What are the characteristics of chronic infarct by cardiac CT?
- LV wall thinning
- Myocardial calcification
- LV remodeling
- LV dilatation
- Lower CT attenuation (due to fatty infiltration)
What is not a typical imaging finding in infective endocarditis?
Valvular stenosis
What are commonly observed findings on cardiac CT in assessment of severe AS?
- Aortic root aneurysm with ST junction effacement
- more common with BAV
- Concentric LVH
- Left atrial dilatation
Describe the findings
Congenitally BAV
- CT findings:
- linear closure of left and right coronary cusp during end-diastole without so much as a raphe to suggest prior separation of these leaflets with calcificaiton
Describe the findings
Myxomatous disease of the mitral valve
- CT findings:
- 2-chamber view shows “billowing” of mitral leaflets past the annulus plane towards the LA during ventricular systole with associated thickened leaflets
What are the best views to confirm mitral valve prolapse on cardiac CT?
3-chamber view or PLAX view
- 2-chamber and 4-chamber views tend to overestimate the prolapse
When performing CCTA on patients with severe AS, what medications should be avoided / or used with caution?
BB and Nitrates
- AS patients have a fixed LVOTO and are unable to augment CO much to compensate for hypotension (from either BB or Nitrates)
- any augmentation in CO, occurs predominatly through increased HR, which is blunted with BB due to scanning
Which phase (in %) of the R-R interval should be selected for CT image reconstruction to perform planimetric measuremet of the aortic valve orifice area (AVA) in AS evaluation?
10-20%
- CT images should be reconstructed during mid-systole, using retrospective ECG-gating –>
- phase of maximal and stabilized aortic valve opening
Which plane (view) should be used for evaluation of aortic valve morphology?
SAX of the LVOTO
- Axial images –> give an oblique view of the AV and are not appropriate to use
Describe CT technique for mitral regurgitation
- Only seen during systole (5-25% of R-R interval)
- Appropriate:
- Prospective and Retrospective
- ECG-gating
- 100 kVp
Describe the findings
- Image reconstruction at 70% R-R interval
ASD + PV stenosis
- ASD
- L-to-R shunting of blood
- located in the fossa ovalis
- likely secondary to small secundum ASD or stretched PFO
- PV stenosis
- stenosis of the left lower pulmonary vein at the left atrial insertion
- Papillary muscle
- normal in size
What is a common association with sinus venosus ASD?
PAPVR (partial anomalous pulmonary venous return)
- Inferior sinus venosus ASD
- IVC - RA communication
- RIPV (right inferior pulmonary vein) PAPVR
- Superior sinus venosus ASD
- SVC - RA communication
- RUPV (right upper pulmonary vein) PAPVR
What is a common associated finding with persistent left SVC?
Primum or Secundum ASD
Describe the findings
Persistent L SVC
- CT findings:
- contrast-filled structure betwee the LAA and the L superior pulmonary vein
- Asymptomatic, finding
- Clinical importance (R sided placement):
- PPM or ICD
- Central venous catheter
Describe the findings
Unroofed coronary sinus (CS) –> enlarged RA, RV, dilated coronary sinus
- left-to-right shunt and RV volume overload
What is the most common course of the esophagus in the posterior mediastinum?
Paramedian left - (88-93%)
- Paramedian right - (12%)
- important consideration to avoid complications such as atrial-esophageal fistula in the context of atrial ablation procedures
What contrast injection protocol should be used for Ct of the cardiac veins?
- planning for biventricular PPM implantation
Delayed arterial phase
- +/- 5-10 seconds after peak of ascending aorta or the coronary arteries
Where is the Thebesian valve located?
Orifice of the coronary sinus
- semicircular fold at the orifice of the coronary sinus
- visualized in 33% of cases
Where is the Vieussens valve located?
located in the great cardiac vein near the beginning of the coronary sinus
- serves as an anatomic landmark
Where is the Eustachian valve located?
RA
- endocardial fold that arises from:
- anterior margin of the IVC –>
- anterior part of the limbus fossa ovalis
Describe the findings
PFO - contrast between the septum primum and the septum secundum
- if there is contrast passing through the interatrial septum into the RA –> PFO
What is the lower limit cutoff for a normal LVEF by cardiac CT?
> 55%
What is the lower limit cutoff for a normal RVEF?
48%
What is the normal interventricular basal septal thickness at end-diastole?
9-11 mm
- all measurements taken at end-diastole
What is the normal thickness of the apical thin point?
1-3 mm (in width)
- short segment at the apex of the LV, where all fibers converge to a thin fibrosis point
What is the normal thickness of the mid-chamber LV walls in end-diastole?
6-11 mm
What is the normal LA volume immediately before mitral valve opening?
57-105 mL
What is the normal RA volume immediately before opening of the TV?
75-115 mL
Describe the findings/diagnosis
Myxoma
- 25-50% of all primary cardiac tumors
- size: 1-15 cm
- Most common locations:
- LA 60-75%
- RA 20-28%
Describe the findings:
Lipoma
- 8-12% of primary cardiac tumors
- encapsulated, contain neoplastic fat cells and occur at young ages
What is the most likely diagnosis of the appearance of the interatrial septum?
Lipomatous hypertrophy of the interatrial septum (LHIS)
-
bilobed, “dumbbell-shaped” fatty mass must be:
- > 20 mm in thickness and
- spare the foramen ovale
- often found in older and overweight patients
- unlike lipomas, they are uncapsulated and contain lipoblasts and mature fat cells
Describe the findings
Papillary fibroelastoma (on anterior MV leaflet)
- 2-33% of primary benign cardiac tumors
- 80% found on AV or MV leaflets
Describe the findings and differential diagnosis:
Angiosarcoma (biopsy proven)
- CT findings:
- RA mass
- irregular and lobulated contours –> suggesting malignancy
- density –> not suggestive of fat content
- Differetial:
- Angiosarcoma
- Metastases
- Cardiac Lymphoma
Describe the findings
Cardiac Sarcoma (poorly differentiated)
- 24% of primary cardiac malignancies
- most undifferentiated sarcomas are found in the LA
- Common findings:
- discrete mass
- irregular contours
- infiltrative
- necrosis and hemorrhage
What is the origin of the carcinoma invading the heart?
Lung
- most common metastases to the heart and pericardium are from lung cancer
- CT findings:
- bilateral, calcified pleural plaques –> asbestos exposure
What are common primary tumors that metastasize to the heart?
- Lung
- Breast
- Renal
- Lymphoma/Leukemia
- Esophageal
- Melanoma
What are the ways which cardiac metastases occurs?
- Direct invasion
- Lymphatic extension
- Hematogenous spread
- Transvenous extension
*****malignant pericardial effusion is the most common manifestation of metastasis
******Likely from lymphatic extension or direct invasion
Describe the findings
Interatrial septal aneurysm + LHIS
- > 10-15 mm to either chamber size
Describe the findings
Angiosarcoma / Malignant pericardial effusion
- malignant involvement of the pericardium may be primary (less common) or secondary to spread from a nearby or distant focus/malignancy
Describe the findings
PFO
Describe the findings and chamber involved
LA - incomplete septation of LA / Cor triatriatum sinister
- congenital anomaly in which the left or right atrium is divided into two parts by a fold of tissue, a membrane, or a fibromuscular band
Describe the findings
SVC syndrome
- mass invading much of the heart, including the LA
- CT findings:
- injected contrast flows through the azygous vein rather than the SVC –>
- indicating that the SVC is at least partially obstructed at some level
Describe the findings
Tetralogy of Fallot
- CT findings:
- Left pain
- right-sided aortic arch
- present in 25% of cases
- Middle pain
- severe hypoplasia of the pulmonary infundibulum
- subvalvular or valvular RVOT stenosis
- Right pain
- overriding aorta
- VSD
- RVH
- Left pain
Describe the findings
Pericardiophrenic bundle
- consists of the phrenic nerve, accompanied by an artery and a vein
- CT findings:
- artery is brightly seen
- vein can also be seen (faintly)
- Can be located on R or L sides
Describe the findings
Muscular VSD
- surrounded on all sides by myocardium
Describe the findings / diagnosis
PAPVR - Scimitar syndrome
- specific form of PAPVR in which all venous drainage from a particular lung (vast majority right lung) lobe drains into the IVC
- syndrome is named for its appearance on frontal CXR wherein the anomalous pulmonary vein creates a crescent-shaped projection along the R sided cardiac border –> resembling a Turkish scimtar sword
- Common associations:
- hypoplastic right lung
- Surgical repair is typically required
Describe the findings
Unroofed coronary sinus
