CT - Chapter 8

Question 1

How can a myocardial perfusion defect be differentiated from an artifact?

Answer 1

• True perfusion defect will:
  
  • persist throughout multiple, different phases of the cardiac cycle
  • visualized in both systole and diastole

Question 2

Which are the best window width and window level for assessing myocardial perfusion defects, respectively?

Answer 2

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

Question 3

Which coronary artery distribution is affected by the perfusion defect displayed in the image?

Answer 3

LCx or RCA (depending on dominance)

• perfusion defect involving the inferior, inferoseptal and inferolateral walls

Question 4

Describe the finding:

Answer 4

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

Question 5

What are the characteristics of chronic infarct by cardiac CT?

Answer 5

• LV wall thinning
• Myocardial calcification
• LV remodeling
• LV dilatation
• Lower CT attenuation (due to fatty infiltration)

Question 6

What is not a typical imaging finding in infective endocarditis?

Answer 6

Valvular stenosis

Question 7

What are commonly observed findings on cardiac CT in assessment of severe AS?

Answer 7

• Aortic root aneurysm with ST junction effacement
  
  • more common with BAV
• Concentric LVH
• Left atrial dilatation

Question 8

Describe the findings

Answer 8

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

Question 9

Describe the findings

Answer 9

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

Question 10

What are the best views to confirm mitral valve prolapse on cardiac CT?

Answer 10

3-chamber view or PLAX view

• 2-chamber and 4-chamber views tend to overestimate the prolapse

Question 11

When performing CCTA on patients with severe AS, what medications should be avoided / or used with caution?

Answer 11

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

Question 12

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?

Answer 12

10-20%

• CT images should be reconstructed during mid-systole, using retrospective ECG-gating –>
• phase of maximal and stabilized aortic valve opening

Question 13

Which plane (view) should be used for evaluation of aortic valve morphology?

Answer 13

SAX of the LVOTO

• Axial images –> give an oblique view of the AV and are not appropriate to use

Question 14

Describe CT technique for mitral regurgitation

Answer 14

• Only seen during systole (5-25% of R-R interval)
• Appropriate:
  
  • Prospective and Retrospective
  • ECG-gating
  • 100 kVp

Question 15

Describe the findings

• Image reconstruction at 70% R-R interval

Answer 15

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

Question 16

What is a common association with sinus venosus ASD?

Answer 16

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

Question 17

What is a common associated finding with persistent left SVC?

Answer 17

Primum or Secundum ASD

Question 18

Describe the findings

Answer 18

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

Question 19

Describe the findings

Answer 19

Unroofed coronary sinus (CS) –> enlarged RA, RV, dilated coronary sinus

• left-to-right shunt and RV volume overload

Question 20

What is the most common course of the esophagus in the posterior mediastinum?

Answer 20

Paramedian left - (88-93%)

• Paramedian right - (12%)
• important consideration to avoid complications such as atrial-esophageal fistula in the context of atrial ablation procedures

Question 21

What contrast injection protocol should be used for Ct of the cardiac veins?

• planning for biventricular PPM implantation

Answer 21

Delayed arterial phase

• +/- 5-10 seconds after peak of ascending aorta or the coronary arteries

Question 22

Where is the Thebesian valve located?

Answer 22

Orifice of the coronary sinus

• semicircular fold at the orifice of the coronary sinus
• visualized in 33% of cases

Question 23

Where is the Vieussens valve located?

Answer 23

located in the great cardiac vein near the beginning of the coronary sinus

• serves as an anatomic landmark

Question 24

Where is the Eustachian valve located?

Answer 24

RA

• endocardial fold that arises from:
  
  • anterior margin of the IVC –>
  • anterior part of the limbus fossa ovalis

Question 25

Describe the findings

Answer 25

**PFO - contrast between the septum primum and the septum secundum** * if there is contrast passing through the interatrial septum into the RA --\> PFO

Question 26

What is the lower limit cutoff for a normal LVEF by cardiac CT?

Answer 26

**\> 55%**

Question 27

What is the lower limit cutoff for a normal RVEF?

Answer 27

**48%**

Question 28

What is the normal interventricular basal septal thickness at end-diastole?

Answer 28

**9-11 mm** * all measurements taken at end-diastole

Question 29

What is the normal thickness of the apical thin point?

Answer 29

**1-3 mm (in width)** * short segment at the apex of the LV, where all fibers converge to a thin fibrosis point

Question 30

What is the normal thickness of the mid-chamber LV walls in end-diastole?

Answer 30

**6-11 mm**

Question 31

What is the normal LA volume immediately before mitral valve opening?

Answer 31

**57-105 mL**

Question 32

What is the normal RA volume immediately before opening of the TV?

Answer 32

**75-115 mL**

Question 33

Describe the findings/diagnosis

Answer 33

**Myxoma** * **25-50%** of all primary cardiac tumors * size: **1-15 cm** * Most common locations: * **LA 60-75%** * **RA 20-28%**

Question 34

Describe the findings:

Answer 34

**Lipoma** * **8-12%** of primary cardiac tumors * encapsulated, contain neoplastic fat cells and occur at young ages

Question 35

What is the most likely diagnosis of the appearance of the interatrial septum?

Answer 35

**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

Question 36

Describe the findings

Answer 36

**Papillary fibroelastoma (on anterior MV leaflet)** * **2-33%** of primary benign cardiac tumors * **80%** found on AV or MV leaflets

Question 37

Describe the findings and differential diagnosis:

Answer 37

**Angiosarcoma (biopsy proven)** * CT findings: * ​RA mass​ * irregular and lobulated contours --\> suggesting malignancy * density --\> not suggestive of fat content * Differetial: * Angiosarcoma * Metastases * Cardiac Lymphoma

Question 38

Describe the findings

Answer 38

**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

Question 39

What is the origin of the carcinoma invading the heart?

Answer 39

**Lung** * most common metastases to the heart and pericardium are from lung cancer * CT findings: * bilateral, calcified pleural plaques --\> asbestos exposure

Question 40

What are common primary tumors that metastasize to the heart?

Answer 40

* Lung * Breast * Renal * Lymphoma/Leukemia * Esophageal * Melanoma

Question 41

What are the ways which cardiac metastases occurs?

Answer 41

* 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

Question 42

Describe the findings

Answer 42

**Interatrial septal aneurysm + LHIS** * \> 10-15 mm to either chamber size

Question 43

Describe the findings

Answer 43

**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

Question 44

Describe the findings

Answer 44

**PFO**​

Question 45

Describe the findings and chamber involved

Answer 45

**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

Question 46

Describe the findings

Answer 46

**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

Question 47

Describe the findings

Answer 47

**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

Question 48

Describe the findings

Answer 48

**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

Question 49

Describe the findings

Answer 49

**Muscular VSD** * surrounded on all sides by myocardium

Question 50

Describe the findings / diagnosis

Answer 50

**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

Question 51

Describe the findings

Answer 51

**Unroofed coronary sinus**