CARDIAC IMAGING 3 Flashcards

• Cyanotic with increased vascularity

• Types
• D-TGA
  
  • Aorta originates from RV
  • PA originates from LV
  • Normal position of atria and ventricles: AV concordance
• L-TGA
  
  • Transposition of great arteries
  • Inversion of ventricles: AV discordance

• Two independent circulations exist:
  
  • Blood returning from body → RV → blood delivered to body
  • Blood returning from lung → LV → blood delivered to lung
• This circulatory pattern is incompatible with life unless there are associated anomalies that permit mixing of the two circulations (e.g., ASD, VSD, or PDA).

Hemodynamics

Depends on the type of mixing of the two circulations

• Plain radiograph
• “Egg-on-side” cardiac contour:
  
  • narrow superior mediastinum secondary to hypoplastic thymus (unknown cause) and abnormal relationship of great vessels
• As pulmonary resistance decreases, pulmonary vascularity increases
• Right heart enlargement
• Pulmonary trunk not visible because of its posterior position

• Treatment
  
  • PGE 1 is administered to prevent closure of PDA. Palliative measures include temporization methods before definitive repair. Corrective operation performed during first year of life:
    
    • Correct reattachment of large vessels (Jatene arterial switch procedure)
    • Creation of an atrial baffle (Mustard, Senning, or Schumaker procedure) Rashkind procedure: atrial septostomy with balloon
    • Blalock–Hanlon: surgical creation of atrial defect

Corrected Transposition of Great Arteries:

• AKA:
  
  • (L-TGA)
  • Levo-transposition
• Large vessels and ventricles are transposed (AV discordance and ventriculoarterial discordance). Poor prognosis because of associated cardiac anomalies. If isolated, this is an acyanotic lesion.

Associations

1. Perimembranous VSD, >50%
2. Pulmonic stenosis, 50%
3. Anomaly of tricuspid valve
4. Dextrocardia

• Plain radiograph
  
  • Pulmonary trunk and aorta are not apparent because of their posterior position.
  • LA enlargement
  • Abnormal AA contour because of the leftward position of the arch
  • Right pulmonary hilus elevated over left pulmonary hilus
• US
  
  • Anatomic LV on right side
  • Anatomic RV on left side
• Cardiac CT and MRI
  
  • Problem-solving tool, defines anatomy, assess complications such as baffle leaks or thrombosis
• Case courtesy of Dr Sajoscha Sorrentino, Radiopaedia.org, rID: 14874
• Case Discussion
  
  • There is situs inversus with laevocardia.
  • Cardiac pacemaker with unusual placement of the electrode tips is demonstrated.
  • While the heart shadow may not give it away at once, note the unusual position of the pacemaker electrodes.
  • Not only that the patient has situs inversus, this is also a diagnosed case of levo-transposition of the great arteries with an ostium secundum atrial septal defect, large membranous ventricular septal defect and pulmonary (valve) stenosis. He previously underwent Blalock-Taussig shunt procedure, closure of the septal defects and correction of the pulmonary stenosis.

Truncus Arteriosus (TA)

Results from failure of formation of the spiral septum within the TA. As a result, a single vessel (truncus) leaves the heart and gives rise to systemic, pulmonary, and coronary circulation. The truncus has 2 to 6 cusps and sits over a high VSD.

Case courtesy of Dr Vincent Tatco, Radiopaedia.org, rID: 43228

There is cardiomegaly.

Lungs are hyperinflated with increased pulmonary vascularity.

Right-sided aortic arch is demonstrated.

Case Discussion

This is a chest radiograph of a patient with truncus arteriosus type I. The diagnosis was confirmed on echocardiography. Truncus arteriosus is a common differential diagnosis in chest radiographs of cyanotic patients presenting with cardiomegaly, pulmonary plethora and right-sided aortic arch.

2 articles feature images from this case

• Associations
  
  • All patients have an associated high VSD.
  • Right AA, 35%

• Types ( Figs. 2.49 – 2.50 )
• Type 1 (most common): Short main PA from truncus
• Type 2: Two separate PAs from truncus (posterior origin)
• Type 3 (least common): Two separate PAs from truncus (lateral origin)
• Type 4 (pseudotruncus) PA from descending aorta = pulmonary atresia with VSD; findings of a tetralogy of Fallot combined with pulmonary atresi

• Hemodynamics
• Admixture lesion with both L–R (truncus → PA) shunt and R–L (RV → VSD → overriding aorta) shunt.

• Radiographic Features
  
  • Plain radiograph
    
    • Enlargement of aortic shadow (which actually represents the truncus)
    • Cardiomegaly because of increased LV volume
    • Increased pulmonary vascularity
    • Pulmonary edema, occasionally present
    • Right AA, 35%
  • US, MRI, cardiac CT, and angiography to determine type

• Treatment
  
  • Three-step surgical procedure:
    
    • 1. Closure of VSD so that LV alone empties into truncus
    • 2. PAs removed from truncus and RV-PA conduit placed
    • 3. Insertion of a valve between the RV and PA
• https://pubs.rsna.org/doi/full/10.1148/rg.2017160033

Total Anomalous Pulmonary Venous Connection (TAPVC) ( Fig. 2.51 )

• Pulmonary veins connect to:
  
  • systemic veins or the
  • RA
• rather than to the LA.
• TAPVC exists when all pulmonary veins connect anomalously.
• The anomalous venous return may be obstructed or nonobstructed.

• Supracardiac connection
  
  • (50%)
    
    • Supracardiac TAPVC is the most common type
    • infrequently associated with obstruction.
      
      • Left vertical vein
      • SVC
      • Azygos vein
• Cardiac connection
  
  • (30%)
    
    • RA
    • Coronary sinus
    • Persistent sinus venosus
• Infracardiac connection
  
  • (15%)
  • majority are obstructed
    
    • PV
    • Persistent ductus venosus
    • IVC (caudal to hepatic veins)
    • Gastric veins
    • Hepatic veins
• Mixed types (5%)

• Associations
  
  • Patent foramen ovale, ASD (necessary to sustain life)
  • Heterotaxy syndrome (asplenia more common)
  • Cat’s eye syndrome

• Symptomatology depends on presence or absence of obstruction
  
  • Obstructed:
    
    • pulmonary edema within several days after birth
  • Nonobstructed:
    
    • asymptomatic at birth. CHF develops during first month.
• 80% mortality by first year

Hemodynamics

Unobstructed Pulmonary Vein

TAPVC causes a complete L-R shunt at the atrial level; therefore to sustain life, an obligatory R-L shunt must be present. Pulmonary flow is greatly increased, leading to dilatation of RA, RV, and PA.

• Obstructed Pulmonary Vein
  
  • Obstruction has three consequences:
    
    • 1. PVH and PAH
    • 2. Pulmonary edema
    • 3. Diminished pulmonary return to the heart, which results in low cardiac output

In cases where the pulmonary veins are obstructed,

the return of oxygenated blood to the heart is

impeded. Consequently, the proportion of oxygenated

blood in the right atrium is reduced, thus, greater

desaturation follows. Furthermore, obstruction to the

pulmonary venous return leads to back-pressure in the

pulmonary venous system, resulting in pulmonary

venous congestion, which has a classical chest X-ray

appearance. Clinically, this manifests as worsening

desaturation and an increased work of breathing as

seen in this case

• Plain radiograph of nonobstructed TAPVC
  
  • Snowman heart (figure-of-eight heart) in supracardiac type; the supracardiac shadow results from dilated right SVC, vertical vein, and innominate vein.
  • Snowman configuration ( Fig. 2.55 ) not seen with other types
    
    • Increased pulmonary vascularity
    • Plain radiograph of obstructed TAPVC
    • Pulmonary edema
    • Small heart
• Case courtesy of Dr Aditya Shetty, Radiopaedia.org, rID: 27800

• Plain radiograph of obstructed TAPVC
  
  • Pulmonary edema
  • Small Heart

https://www.eurorad.org/case/1687

The heart is normal in size and there is bilateral airspace opacification, consistent with pulmonary oedema.

A full-term infant with uneventful delivery presented with respiratory distress, difficulty in feeding and cyanosis. The oxygen saturation by pulse oximeter was 50% in room air. Septic screen was negative and there was no history of haemoptysis.

IMAGING FINDINGS

After an uncomplicated birth at term and discharge home well at day two of life, the patient presented with gradual shortness of breath and difficulty in feeding due to tiredness over a 10-day period. At a routine postnatal check it was noticed that he was dusky and in mild respiratory distress. On transfer to the Casualty department, the oxygen saturation was found to be 50% in room air. He was apyrexial and the white cell count was normal. An initial chest radiograph demonstrated a normal-sized heart with normal pulmonary vascularity and clear lungs.

The patient deteriorated over the next few hours, requiring intubation and ventilation. There was no history of haemoptysis or of visualised blood during intubation. A repeat chest radiograph was obtained (Fig. 1). It demonstrated a normal-sized heart and diffuse bilateral airspace opacification consistent with pulmonary oedema. Pleural effusions were not present. The upper mediastinum was not widened. In view of the history of cyanosis and respiratory distress with an oxygen saturation of 50% and the rapid onset of airspace opacification with a normal heart size a provisional diagnosis of obstructed total anomalous pulmonary venous return was made. An echocardiogram was performed and confirmed the presence of a common pulmonary venous chamber, behind the left atrium, which accepted all four pulmonary veins and which connected to the infradiaphragmatic IVC by an obstructed vertical vein. A small 6mm restrictive ASD shunting from right to left was also found. The ventricular septum was normal; mild tricuspid regurgitation was noted. The main pulmonary artery was enlarged, a PDA was also present, again with right to left shunting. The aortic arch was left sided and normal. The left ventricular outflow tract was normal. The IVC and SVC were connected to a morphologic right atrium.

Supportive medical therapy was instigated and the patient underwent cardiac surgery within 24 hours. At surgery the findings on echo were confirmed and repaired. The common chamber receiving all four pulmonary veins was anastomosed to the left atrium and the ASD was sutured closed. The patient was discharged home well on full feeds on day 20 post-op.