Category: Image of the Month

Authors: Laura Duerden¹, Tom Chance¹, Jonathan Rodrigues², Stephen Lyen¹, Mark Hamilton¹, Nathan Manghat¹

Affiliations:

1 Department of Radiology, Bristol Royal Infirmary, United Kingdom

2 Department of Cardiothoracic Imaging, Toronto General Hospital, Toronto

Case

A 17 year-old girl presented with palpitations.  She had no past medical history and no family history of cardiac disease.  Clinical examination and initial investigations including trans-thoracic echocardiography showed no abnormality. 24-hour electrocardiograph holter monitoring revealed frequent ventricular ectopic beats.

Owing to persistent symptoms, she was referred for cardiac magnetic resonance imaging (CMR). This showed mildly impaired left ventricular function, with hypokinesia and thinning / irregularity of the left antero-lateral and infero-lateral ventricular wall (Fig 1A). There was evidence of patchy epicardial late gadolinium enhancement in the lateral LV wall (Fig 1B) on the post-gadolinium sequence. No right ventricular abnormality was demonstrated. A provisional diagnosis of chronic myocarditis was made but the absence of a prolonged period of chest pain in her clinical history was felt to be unusual and an interval CMR was performed one year later. This showed nodular signal abnormality in the left ventricular lateral wall which was hyper-intense to myocardium and iso-intense to fat on T1-weighted sequences (Fig 1C) and the exhibited homogenous signal drop out with fat suppression techniques (Fig 1D), implying focal fibro-fatty infiltration.

She went on to have a cardiac CT, performed with unenhanced and delayed phase imaging, to characterize the apparent nodular soft tissue seen on CMR. This confirmed abnormal lobulation of the left ventricular wall.  There were multiple areas of focal epicardial thinning.  The thin walled sections were invaginated by epicardial fat and blood vessels (Fig 2). The right ventricle was normal.

A diagnosis of arrythmogenic left ventricular cardiomyopathy (ALVC) was made. The patient was treated with bisoprolol to control palpitations and has remained well with no decline in left ventricular function.  First-degree relatives have been screened with no other affected family members identified.

Figure legends

Figure 1

A) 4-chamber steady state free precession image demonstrating irregularities of  left ventricular antero-lateral left ventricular wall (white arrows).

B) 3-chamber late gadolinium enhancement magnitude image demonstrating foci of epicardial enhancement in the infero-lateral left ventricular wall (white arrows).

C) Mid-ventricular short-axis T1-weighted image demonstrating epicardial foci of signal hyper-intense to myocardium and iso-intense to fat (white arrows).

D) Mid-ventricular short-axis T1-weighted fat-saturated image demonstrating homogenous signal drop out in the epicardial foci demonstrating high T1-weighted images in Figure 1C consistent with foci of epicardial fat.

Figure 2

A) Axial unenhanced ECG-gated cardiac CT image demonstrating foci of fat attenuation in the left ventricular lateral wall (white arrows).

B) Axial delayed ECG-gated cardiac CT image demonstrating foci of fat attenuation discrete to the enhancing myocardium in the left ventricular lateral wall (white arrows).

C) Reconstructed left ventricular short-axis delayed ECG-gated cardiac CT image demonstrating foci of fat attenuation discrete to the enhancing myocardium in the left ventricular lateral wall (white arrows).

Discussion

ALVC is an increasingly recognised condition, characterised by fibro-fatty replacement in the left ventricle wall.  It is closely related to the more widely recognised arrythmogenic right ventricular cardiomyopathy, where the right ventricle is affected. The two disease patterns frequently co-exist within the same family and genes implicated in ARVC have also been identified in patients with ALVC.

Arrythmogenic cardiomyopathies are distinct from dilated cardiomyopathy (DCM) by predominately resulting in arrhythmia, rather than ventricular dysfunction. This is an important clinical diagnosis to be aware of as the major complication is sudden cardiac death due to malignant arrhythmia. Clinical heart failure is rarely seen.

Multiple-choice questions

Question 1:

Which of these is a CMR feature of myocarditis?

A) Focal, non-ischaemic lesion demonstrating late gadolinium enhancement

B) T2 signal decrease in myocardium

C) Decreased global myocardial early gadolinium enhancement ratio.

D) Intramyocardial fat

Answer:

A) Focal, non-ischaemic lesion demonstrating late gadolinium enhancement

The Lake Louise CMR criteria1 are used to diagnose myocarditis. If ≥ 2 of the following features are present, in the correct clinical context, then a diagnosis of myocarditis should be considered:

1) the presence of at least one, focal, non-ischaemic lesion demonstrating late gadolinium enhancement.

2) regional / global myocardial signal increase on T2-weighted images.

3) increased global myocardial early gadolinium enhancement ratio (EGEr).

Question 2:

Mutations in which of these genes is most frequently associated with arrythmogenic cardiomyopathy?

A) Collagen IV

B) Desmoplakin

C) Laminin

D) Plectin

Answer:

B) Desmoplakin

When a diagnosis of arrythmogenic cardiomyopathy is made, it is important to perform familial screening. This may include a genetic screen for genotype mutations in genes such as desmoplakin2 which may be implicated in the clinical phenotype in the proband.

Question 3:

What pattern of late gadolinium enhancement would be most consistent with a diagnosis of idiopathic dilated cardiomyopathy?

A) Epicardial

B) Mid-wall

C) Subendocardial

D) Transmural

Answer:

B) Mid-wall

Mid-wall LGE is associated with idiopathic dilated cardiomyopathy. However, mid-wall fibrosis is only seen in approximately 30% of individuals with idiopathic DCM3. Epicardial LGE is described in ARVC and ALVC.  Subendocardial and transmural LGE are associated with ischaemic heart disease4.

Question 4:

Which of the following criteria was not part of the Modified Task Force Criteria for the diagnosis of arrhythmogenic right ventricular cardiomyopathy / dysplasia?

A ) Arrhythmias

B) Conduction / repolarization abnormalities

C) Endomyocardial biopsy

D) Family history

E) Global or region dysfunction

Answer:

C) Endoymocardial biopsy

For more information see the proposed modification of the Task Force Criteria5.

References

1 Friedrich MG, et al. Cardiovascular magnetic resonance in myocarditis: a JACC white paper. J Am Coll Cardiol. 2009; 53: 1475-87

2 Sen-Chowdhry S, et al. Left-dominant arrhythmogenic cardiomyopathy: an under-recognized clinical entity. J Am Coll Cardiol 2008; 52: 2176-87.

3 Assomull RG, et al. Cardiovascular magnetic resonance, fibrosis, and prognosis in dilated cardiomyopathy. J Am Coll Cardiol. 2006; 48: 1977-85

4 Mahrholdt H, et al. Delayed enhancement cardiovascular magnetic resonance assessment of non-ischaemic cardiomyopathies. Eur Heart J. 2005; 26: 1461-74

5 Marcus FI, et al. Diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia: proposed modification of the Task Force Criteria. Eur Heart J. 2010: 31: 806-14

Submitted by Dr Carina Brolund-Napier (CT2 Core Medical Trainee), Dr Amit Parekh (Radiology SPR), Dr Rajiv Singh (Consultant Radiologist,), Dr Garrett McGann (Consultant Radiologist). Gloucestershire Hospitals NHS Foundation Trust, UK.

A 65 year old man presented with atypical chest discomfort and dyspnoea on a background of hypertension, hypercholesterolaemia and a positive family history of coronary artery disease. Coronary angiography showed diffuse calcific atheroma, ectatic arteries, a coronary aneurysm and a coronary-pulmonary fistula. Further imaging with computed tomography (CT) coronary angiography identified a complex fistula between a branch of the proximal left anterior descending artery feeding into a 31mm x 33mm aneurysmal segment around the right ventricular outflow tract (RVOT), in turn fistulating with the pulmonary trunk.  There was also a collateral network of dilated tortuous vessels seen anastomosing around the RVOT in keeping with a Vieussens arterial ring, a collateral pathway between the right and left coronary arteries. There was no demonstration of ischaemia on stress MRI.

Seven years later, the patient was re-referred to cardiology with intermittent atypical chest discomfort. A repeat cardiac CT showed the aneurysm had increased in size to 51mm x 55mm with possible thrombus formation. The case was discussed at the cardiothoracic MDT where the consensus of opinion was that due to the risk of rupture this would likely require surgical repair. Further imaging with coronary angiography was recommended to ascertain if coronary intervention would be necessary at the time of surgery.

Figure 1: Imaging at first presentation

1a – Three-dimensional reconstruction CT coronary angiography. A network of dilated tortuous collateral coronary vessels with a 31mm x 33mm aneurysm lying between the circumflex and left main stem.

1b – Axial image from CT coronary angiography demonstrating the left coronary artery feeding into the coronary aneurysm.

1c – Axial image from CT coronary angiography demonstrating an aneurysmal coronary artery fistulating into the pulmonary trunk (white arrow)

1d – Axial image from CT coronary angiography demonstrating a network of dilated tortuous vessels overlying the pulmonary trunk.

Figure 2: Imaging seven years later. 

2a – Three-dimensional CT coronary angiogram image demonstrating enlargement of the main aneurysm to 51mm x 55mm.

2b – Axial image from CT coronary angiography demonstrating the aneurysm had increased in size to 51mm x 55mm. Low density is seen within the aneurysm suggesting either low flow or clot formation.

Discussion

Coronary artery fistulas (CAF) are anomalous terminations of the coronary arteries and are identified in 0.05% – 0.25% of patients who undergo coronary angiography.¹ The majority of CAF are of congenital origin and adult patients are usually asymptomatic.¹ Most CAF arise from the right coronary artery (50%), followed by the left coronary artery  (42%) and less commonly both the right and left coronary arteries (5%).¹ CAF involving the pulmonary trunk are very rare.

Vieussens’ arterial ring (VAR) is a collateral pathway between the conus branches of the right and left coronary arteries. It is a normal anatomical variant and is rarely associated with any pathological conditions. As was the case in this patient, the presence of both a CAF into the pulmonary trunk and an aneurysm within VAR is extremely rare with very few other reported cases.² There is one report of rupture of a 3.5cm aneurysm of VAR that was successfully treated by surgical repair.³

The management of simple CAF is controversial. In asymptomatic patients there is no urgency to close CAF and close follow-up for several years is useful. Antiplatelet and prophylactic precautions against bacterial endocarditis are recommended.¹ Surgical ligation and transcatheter embolization have similar early effectiveness and patients may have an excellent prognosis following either procedure.¹ However, the optimum management for large and complex CAF (as in this case) is unknown. We would therefore welcome feedback from readers about how you feel this case could be managed.

Multiple Choice Questions

1. Which coronary vessel do the majority of symptomatic CAF arise from?
   1. LCA
   2. RCA
   3. Circumflex
   4. LAD
   5. Both RCA and LCA

1. What is the most common clinical presentation of CAF?
   1. Dyspnoea
   2. Chest pain
   3. Sudden death
   4. Continuous heart murmur
   5. Stroke

1. What is the chance of spontaneous closure of a CAF?
   1. 0.01%
   2. 1%-2%
   3. 10 -15%
   4. 25%
   5. 50%

References

1. Zenooz NA. et al.  Coronary Artery Fistulas: CT findings. Radiographics 2009; 29:781-789.
2. Lee HY, Cho SH. An Unusual Form of Coronary Artery Fistula: A Small Aneurysm of Vieussens’ Arterial Ring Communicating with the Pulmonary Artery. Korean J Thorac Cardiovasc Surg. 2014; 47:152-154
3. Health A. Rupture of an aneurysm of Vieussens’ arterial ring presenting as acute cardiac tamponade. Clinical Radiology 2009; 64, 1129-1131

Answers1:  1 = b, 2 = d, 3 = b

Dr Lily Lei, Royal Infirmary of Edinburgh

Dr Michelle C Williams, University of Edinburgh

A 54 year old female ex-smoker presented with a ten year history of exertional breathlessness and occasional wheeze. On examination she had a soft ejection systolic murmur consistent with a pulmonary flow murmur. Electrocardiography showed right bundle branch block and echocardiography showed a superior sinus venosus atrial septal defect and a dilated right ventricle with preserved systolic function. Cardiac computed tomography demonstrated partial anomalous pulmonary venous drainage from the right upper and middle lobes. She was referred for surgery.

Atrial septal defects (ASD) are classified into three major types, namely ostium secundum, ostium primum, and sinus venosus defects.  Ostium secundum, the most common type of ASD, is a defect within the region of the fossa ovalis. Ostium primum defects are variants of atrioventricular septal defects. Sinus venosus defects are interatrial communications that usually involve the junction of the right atrium and superior vena cava ¹, but less commonly can involve the venous inflow of the inferior vena cava.

The superior form of the sinus venosus ASD accounts for 5 – 10% of all ASDs ¹, and is usually associated with partial anomalous pulmonary venous return (PAPVR).  PAPVR is the drainage of one or more pulmonary veins into the right atrium or systemic circulation instead of the left atrium ². Sinus venosus ASD is associated withright-sided PAPVR, with anomalous drainage of one or more right pulmonary veins into the superior vena cava or right atrium ³.

References

Multiple choice questions

1. The three major types of atrial septal defects are:

A. Ostium secundum, ostium primum, ostium arteriosis

B. Ostium secundum, ostium primum, sinus venosus

C. Ostium secundum, ostium primum, sinus arteriosis

D. Ostium primum, sinus venosus, ductus arteriosis

E. Ostium primum, sinus venosus, partial anomalous pulmonary venous return

2. Which of the following is true regarding atrial septal defects:

A. Atrial septal defects are an uncommon cause of congenital heart disease

B. Downs syndrome is associated with atrioventricular septal defects

C. Sinus venosus defects are always easy to identify on transthoracic echocardiography

D. Cardiac catheterization is essential for diagnosis

E. Atrial septal defects are a common cause of cyanosis

3. Chest x-ray features of atrial septal defects may include

A. Cardiomegally

B. Enlarged central pulmonary arteries

C. Pulonary plethora

D. Small aortic knuckle

E. All of the above

Answers

1, B

2, B

3, E

An 85-year-old woman with chronic obstruction pulmonary disease was referred to the Heart Team for consideration of transcatheter aortic valve implantation (TAVI). She had severe aortic stenosis (mean aortic valve pressure gradient 61mmHg, maximum aortic valve pressure gradient 111mmHg) with mild left ventricular systolic dysfunction. She was a life-long smoker with pulmonary function testing revealing an FEV1 1.48L. Electrocardiography demonstrated sinus rhythm with right bundle branch block and left axis deviation. Cardiac computed tomography was performed to assess suitability for TAVI.

QUESTION

What one of the following would confirm a diagnosis of severe aortic stenosis?

ANSWER C

Calcium score thresholds (men 2065 Agatston Units, women 1274 Agatston Units) differentiate moderate from severe AS [1]. Echocardiographic parameters of severe aortic stenosis (AS) include an increased aortic valve velocity (aortic valve maximum velocity 4 m/sec, maximum pressure gradient 64 mmHg (4v2), mean pressure gradient 40 mmHg). When cardiac output is reduced (i.e. LV systolic dysfunction), a velocity ratio of 4:1 (<0.25) is suggestive of severe AS. A delayed time to peak velocity (>100 msec) represents the late systolic murmur audible on auscultation that is associated with severe AS. [2] Valvulo-arterial impedance >5 mmHg/mL/m2 estimates the LV systolic load suggestive of severe AS and can be useful in patients with hypertrophied,small cavity left ventricles [3].

QUESTION

What features should be considered in this case?

A. Absolute indication for surgical bioprosthesis

B. Increased risk of left coronary artery obstruction

C. Increased risk of high-grade atrioventricular conduction block

D. Increased risk of annular rupture

E. Decreased risk of paravalvular regurgitation

ANSWER D

The correct answer is increased risk of annular rupture. This patient has a trileaflet aortic valve with severe calcification involving all three cusps. A nodule of calcification extends along the left ventricular outflow tract (LVOT) following the course of the aorto-mitral curtain. The coronary arteries arise from their normal aortic sinus with an adequate height from the annulus to the coronary ostia. There is extensive macrocalcification of the anterior (right coronary) aortic valve leaflet which may potentially obstruct the right coronary ostium during TAVI deployment. The extensive LVOT calcification beneath the left coronary artery may penetrate the myocardium and either result in acute rupture of the left ventricular free wall or slowly progress to pseudoaneurysmformation. [4]

Clinical practice guidelines would recommend transfemoralTAVI over surgical aortic valve replacement in this individual. [5] Pre-existing right bundle branch block and increased left coronary cusp calcification are independent risk factors for permanent pacemaker implantations post-TAVI. [6] The shallow sinus of valsalva height would preclude use of a self-expanding valve. [7] Extensive aortic valve calcification is associated with post-procedural prosthesis eccentricity and severity of paravalvular regurgitation [8].

QUESTION

If annular rupture were to occur, which location is most likely?

ANSWER A

The native annulus is severely calcified and prominent calcified shards can protrude through the annulus following balloon-expansion TAVI. Small tears or localised rupture may be ‘contained’ by the transcatheter valve preventing further haemodynamic compromise [4]. Subannular ruptures (free myocardial wall, non-coronary cusp, interventricular septum) occur when LVOT calcification disrupts the aortic-outflow tract continuity. Free myocardial wall rupture is located beneath the anterior portion of the left coronary cusp resulting in catastrophic haemorrhage. Perforation below the non-coronary sinus with calcification in the aorto-mitral continuity can generate large shunts into the left atrium. Interventricularseptum perforations may only be detected due to presence of a new conduction abnormality, however haemotoma formation and ventricular septal defects may occur. Supra-annular ruptures may develop in shallow sinuses with injuries to the sinotubular junction or coronary ostia.

Transfemoral TAVI using a 26mm Sapien 3 prosthesis was performed. Following the procedure there was only trivial paravalvular leak and no alteration to atrioventricularconduction.

References

[1] Clavel MA, Pibarot P, Messika-Zeitoun D, et al. Impact of aortic valve calcification, as measured by MDCT, on survival in patients with aortic stenosis: results of an international registry study. J Am Coll Cardiol. 2014;64:1202-1213.

[2] Kamimura D, Hans S, Suzuki T, et al. Delayed time to peak velocity is useful for detecting severe aortic stenosis. J Am Heart Assoc. 2016;5: e003907 doi: 10.1161/JAHA.116.003907.

[3] Baumgartner H, Hung J, Bermejo J, et al. Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. Eur  J Echocardiogr. 2009;10:1-25.

[4] Pasic M, Unbehaun A, Buz S, et al. Annular rupture during transcatheter aortic valve replacement: classification, pathophysiology, diagnostics, treatment approaches, and prevention. JACC Cardiovasc Interv. 2015;8:1-9.

[5] Vandvik PO, Otto CM, Siemieniuk RA, et al. Transcatheter or surgical aortic valve replacement for patients with severe, symptomatic, aortic stenosis at low to intermediate surgical risk: a clinical practice guideline. BMJ 2016;354:i5085. Doi:10.1136/bmj.i5085.

[6] Fujita B,  Kütting M, Seiffert M, et al.  Calcium distribution patterns of the aortic valve as a risk factor for the need of permanent pacemaker implantation after transcatheteraortic valve implantation. Eur Heart J Cardiovasc Imaging. 2016;17:1385-1393.

[7] Ribeiro HB, Webb JG, Makkar RR, et al. Predictive factors, management, and clinical outcomes of coronary obstruction following transcatheter aortic valve implantation: insights from a large multicenter registry. J Am Coll Cardiol. 2013;62:1552-1562.

[8] Bekeredijan R, Bodingbauer D, Hofmann NP, et al. The extent of aortic annulus calcification is a predictor of postprocedural eccentricity and paravalvular regurgitation: a pre- and postinterventional cardiac computed tomography angiography study. J Invasive Cardiol. 2015;27:172-180.

By Dr Katharine Garfath-Cox

University of Southampton

A 30 year old male presented to the emergency department with atypical chest pain and a mildly elevated troponin. He was referred for a CT coronary angiogram to exclude coronary artery disease.

The CTCA was acquired using a tight bolus of contrast and a region of interest in the ascending and descending aorta to enable maximal contrast density within the coronary arteries. The coronary arteries were normal. The scan demonstrated near equal contrast density within the right and left heart chambers and a significantly dilated right atrium and right ventricle.

A systematic review was employed to discover the site of the presumed left to right shunt. A sinus venosus ASD (figure 1a) was present with associated anomalous drainage of the right superior pulmonary vein (figure 1b,1e,1f).

Discussion:
Atrial septal defects are the most common congenital cardiac anomaly detected in adult patients (1)(2). There are four main types, Ostium Primum, Ostium Secundum, Sinus Venosus Defect and coronary sinus type. The sinus venosus defect occurs in only approximately 5% of cases and these defects are present at the entrance of the SVC and are associated with a partial anomalous pulmonary venous connection (PAPVC).
The clinical presentation may be delayed due to low atrial pressures and even large defects can be well tolerated. The haemodynamic consequence of the defect results in a dilated right atrium and right ventricle with an increase in pulmonary vascularity. The other cardiac chambers remain normal in size.
Diagnosis is often achieved with Echo, however, with an increasing number of CT coronary angiograms being performed, review of cardiac chambers and anomalous connections is essential. The advantage of CT in this case over Echo is the concurrent identification of the site of the PAPVC, important for surgical planning.

Figure legend:
Figure1. Single beat, 16cm detector CTCA.
1a. Axial image showing a large sinus venosus ASD at the level of the entrance of the SVC into the RA (red star).
1b. Axial image of the superior pulmonary vein draining into the lateral aspect of the SVC.
1c. 4 chamber view of the dilated right atrium and right ventricle.
1d. 2 chamber view of the dilated right atrium and right ventricle.
1e. Coronal reformatted image showing the PAPVC.
1f. Cropped coronal reformat of the PAPVC.

Multiple choice questions

1. Which is the most common type of ASD?

A) Ostium primum ASD
B) Superior sinus venosus defect
C) Inferior sinus venosus defect
D) Unroofed coronary sinus type
E) Ostium Secundum ASD

2. What are the haemodynamics of an ASD?

3. This patient re-presents to the emergency department prior to intervention with breathlessness and mild cyanosis. Reversal of the shunt is identified on echocardiogram and a diagnosis of Eisenmenger physiology is made. What finding would be a feature on imaging due to the resultant pulmonary arterial hypertension?

A) Dilated pulmonary veins
B) Small central pulmonary artery
C) Mural calcification in main pulmonary arteries
D) Mural calcification in main pulmonary veins
E) Mural calcification in peripheral pulmonary arteries

4. Which of the following statements is not true regarding PAPVC?

A) Scimitar syndrome is a type of PAPVC
B) Common connections can be classified as supra-cardiac, cardiac or infra-cardiac.
C) 15% have an associated ASD
D) All pulmonary veins drain into the systemic circulation.
E) PAPVC is not always cyanotic

Images with thanks to Dr Russell Bull, Royal Bournemouth Hospital.

Answers

(1 E), (2 A, B= Tetralogy of Fallot , C=Ebstein anomaly, D=PDA), (3 C), (4 D)

By: Dr Alexia Farrugia, Dr Rebecca Preston

Guy’s & St. Thomas’ NHS Trust, London

A 70 year old lady presents with shortness of breath. A chest X-ray revealed deviation of the thyroid gland to the right secondary due to a predominantly left-sided anterior mediastinal mass. CT thorax revealed a thyroid goitre. A thyroidectomy was performed and histology revealed follicular thyroid carcinoma. In view of the relatively de-differentiated tumour, radioiodine ablation was done.

Two years later, the patient was noted on biochemical results to have a high serum calcium level and a rising thyroglobulin. FDG PET-CT was performed showing new focal increased tracer uptake posterior to the left thyroid bed and adjacent to the oesophagus. Also, there was a further focus of increased tracer uptake related to the right ventricle and pulmonary trunk. Appearances were in keeping with local recurrence within the left thyroid bed and an indeterminate new focal uptake within the right ventricle and pulmonary trunk. An urgent fine needle aspiration of the left thyroid nodule was performed and follicular thyroid carcinoma recurrence was confirmed on histology. A CT coronary angiogram revealed a soft-tissue mass anterior to and invading the pulmonary outflow tract and was seen to involve the anterior pericardium. A new pericardial effusion was noted. (Figure).

CT-guided biopsy of the anterior mediastinal mass was performed. Histology revealed round cells strongly positive for TTF-1 and thyroglobulin. Given the histological morphological features and immuno-histochemical profile of the biopsy specimen was consistent with metastatic disease from the known thyroid primary. Neck dissection was performed to excise the suspicious foci of recurrence within the thyroid bed.

Multiple choice questions

1. Which is the most common site of metastatic deposits from thyroid carcinoma?

1. Cardiac / valvular
2. Cervical lymph nodes
3. Lung parenchyma
4. Osseous
5. Hepatic

2. Which is the commonest type of thyroid malignancy?

1. Papillary
2. Follicular
3. Anaplastic
4. Medullary
5. Lymphoma

3. Which are the commonest tumours to metastasise to the heart?

1. Pleural mesothelioma
2. Melanoma
3. Lung adenocarcinoma
4. Breast carcinoma
5. Squamous cell carcinoma of the head and neck

Figures 1A, B & C – CT coronary angiogram reformats. Sagittal, coronal and axial CT coronary angiogram images demonstrating a peripherally-enhancing, centrally necrotic mass within the pulmonary outflow tract, with a moderately-sized pericardial effusion.

Figures 2A & B – 18-F FDG PET-CT images. FDG PET-CT uptake is present within the right ventricular outflow tract and within the left thyroid bed consistent with a metastatic deposit and recurrence of follicular thyroid carcinoma respectively.

Images courtesy of: Guy’s & St Thomas’ NHS Trust & PET Centre at St Thomas’ Hospital, London

Answers: 1=b, 2=b, 3=a.

Will Loughborough, Stephen Lyen, Mark Hamilton

University Hospitals Bristol NHS Foundation Trust

A 30 year old woman with Tetralogy of Fallot was referred for a cardiac computed tomographic examination prior to cardiac surgery. She had a Tetralogy repair in childhood involving a transannular patch. She had developed severe pulmonary valve regurgitation and was undergoing work up for an open pulmonary valve replacement which included coronary arterial assessment. A cardiac MRI demonstrated restrictive RV physiology with early diastolic septal interaction and an end diastolic A wave in the main pulmonary artery flow curve. There was unexplained reduction in LV long axis shortening both on MRI and TTE with probably pseudonormal transmitral Doppler.  A prospectively ECG gated coronary angiogram demonstrated unobstructed coronaries with normal origins. However, it revealed a thick slab of pericardial calcification extending along the posterior atrioventricular groove, with multiple prongs of calcification extending into the basal inferior and lateral left ventricular myocardium (see images) and a single prong into the RV myocardium.

On review, the extensive LV prongs corresponded to tethering of the left ventricle on dynamic imaging with consequent reduced long axis excursion. Both atria and their draining veins were dilated, implying elevated pressure (no shunt). The interatrial septum was central suggesting the pressure was equal.  The right heart findings could be explained by the RV physiology. However, these do not explain the LA findings which would seem most elegantly explained by reduced LV filling, secondary to impaired LV long axis function with secondary diastolic dysfunction. At the same time, the pericardium compressed the LV diameter a little. The conclusion was that the RV dysfunction was substantially due to the pulmonary valve disease. However the LV anatomical and physiological parameters support a diagnosis of mild systolic and diastolic dysfunction. The calcified pericardium caused pericardial constriction leading to impaired ventricular filling. The prongs of calcified pericardium invading the LV myocardium caused restriction on long axis shortening and lengthening (leading to restrictive physiology).

The patient was discussed at the adult congenital cardiac MDT where the decision was to replace the pulmonary valve alone as extensive surgical debridement of the LV pericardium was not considered attractive.

Figure 1

Figure legend

1A Short axis view. Multiple prongs of pericardial calcification extending into basal inferior and lateral left ventricular myocardium

1B Volume rendered image. Thick slab of pericardial calcification extending down the posterior atrioventricular groove

1C Four chamber long axis view. Pericardial calcification extending the basal left ventricular myocardium

Multiple choice questions

1. Treatment of Tetralogy of Fallot with a transannular patch is often associated with regurgitation though which valve?

1. Tricuspid
2. Pulmonary
3. Mitral
4. Aortic

2. Constrictive pathophysiology is usually due to abnormalities in the

1. Myocardium
2. Valves
3. Coronaries
4. Pericardium

3. Restrictive pathophysiology is usually primarily due to abnormalities in the

1. Myocardium
2. Pericardium

Answers

1 – B,  2 – D, 3 – A

Submitted by Parekh A, Turner M, Gamble E, Hamilton MCK. Bristol Royal Infirmary, Upper Maudlin Street, Bristol, UK

A 76 year old lady who presented with hypoxia and shortness of breath was suspected to have pulmonary embolism. She underwent perfusion scintigraphy with Technetium 99m labelled human albumin macro-aggregates (MAA). Normally, the MAA particles lodge in the pulmonary circulation and do not enter the systematic arterial circulation. In this case there was normal lung perfusion but faint tracer uptake in both kidneys (arrows) indicating a right to left shunt though a previous echocardiogram was normal. Oxygen saturations were noted to be 72% on sitting and 88% on lying. A subsequent bubble echocardiogram confirmed a right to left atrial shunt, which was significantly worse on sitting than lying supine. The patient was diagnosed with platypnoea-orthodeoxia syndrome.

Platypnoea-orthodeoxia is a rare cause of a right to left shunt within a pre-existing anatomical defect (usually an atrial septal defect (ASD) or patent foramen ovale). The shunt is more severe in the erect position[1,2]. In this case on sitting or standing the atrial septum was presumably distorted by the unfolded aortic root enlarging the defect and increasing the shunt.

The patient subsequently underwent ASD closure with marked improvement in oxygen saturations and clinical status.

References

[1] Testuz, A., Roffi, M., Müller, H., Blanche, C. and Noble, S. Platypnoea-orthodeoxia syndrome: more than just a PFO.Cardiovascular Medicine. 2014;17(7–8):228–23

[2]Cheng TO. Platypnea-orthodeoxia syndrome: Etiology, differential diagnosis, and management. Cathet Cardiovasc Interv. 1999;47:64–66.

Dr Jonathan Rodrigues, Bristol Heart Institute

Case:

An elderly gentleman presented with chest pain, shortness of breath and haemoptysis. His past medical history was significant for previous type A aortic dissection and ascending aortic repair many years ago. On examination, he was hypoxic and cyanosed. An urgent, non-ECG gated CT aorta was performed. This revealed a large pseudoaneurysm arising from the superior aspect of the ascending aortic repair (Figure 1A and 1B). The pseudoaneurysm was in direct continuity with the right main pulmonary artery (Figure 1A-C). There was evidence of significant left to right shunt from ascending aorta, via the pseudoaneurysm, into the right-sided pulmonary arterial system, with differential opacification of the main pulmonary arteries, with avid right-sided enhancement on the systemic arterial phase study (Figure 1A and 1C). The discrepancy in size of segmental and subsegmental pulmonary arteries, larger in the right lower lobe compared to the left, was suggestive of acute right-sided pulmonary arterial volume loading (Figure 2A). The airspace opacification in the middle and right lower lobes (Figure 2B) was consistent with alveolar oedema and possibly haemorrhage from rapid significantly increased hydrostatic pressure and possibility capillary haemorrhage due to the large volume acute shunt. Unfortunately, the patient deteriorated very quickly and did not survive for definitive surgical correction to be attempted.

Discussion:

Acquired aorto-pulmonary artery fistulation is a rare but life-threatening condition. It may arise as a complication of aortic aneurysms[1] and both acute and chronic aortic dissections[2]. However, progression of a post-aortic surgery pseudoaneurym to an acquired aorto-pulmonary fistula is exceedingly rare. Potential causes for such a rare complication are postulated to include longstanding right pulmonary arterial compression by the pseudoaneurysm, atherosclerosis, connective tissue disorders, necrosis, trauma, inflammatory aortitis and infection [3]. Aorto-pulmonary fistulae can be asymptomatic [4] or more commonly present with congestive heart failure, chest pain and haemoptysis [5]. Definitive treatment of aorto-pulmonary fistulae is usually surgery. However, treatment with Amplatzer Septal Occluder has previous been described [6].

Figure 1. Non-ECG gated arterial phase CT of the thorax.

A) Axial image showing a large ascending aortic pseudoaneurysm (§) exerting mass effect on the ascending aortic graft repair (*), from previous type A aortic dissection. There is a direct connection between the ascending aortic pseudoaneurysm and the right main pulmonary artery (solid white arrow). There is differential opacification of the right and left main pulmonary arteries with more avid enhancement in the right main pulmonary artery (dotted white arrow) compared to the left main pulmonary artery (dashed white arrow) on this arterial phase study.

B) Sagittal reformatted image showing the ascending aortic graft repair (*) with large pseudoaneurysm arising from the proximal aspect of the graft repair (§). The connection between the pseudoaneurysm and the right main pulmonary artery is demonstrated (solid white arrow).

C) Coronal reformatted image showing an abnormal serpiginous connection with the right main pulmonary artery (solid white arrow) and differential opacification of the main pulmonary arteries on this systemic arterial phase study, with more avid opacification of the right main pulmonary artery (dotted white arrow) compared to the left main pulmonary artery (dashed white arrow).

Figure 2. Non-ECG gated arterial phase CT of the thorax

A) Axial image display on mediastinal window settings showing asymmetrical enlargement of the right basal segmental and subsegmental pulmonary arteries (dotted white arrow) compared to the left basal pulmonary arteries (dashed white arrow). There is evidence of previous dissection in the descending thoracic aorta with opacified oval-shaped true lumen (black *) and thrombosed false lumen (white *).

B) Axial image displayed on lung window settings showing focal consolidation in the right lower lobe (*) and the lateral segment of the middle lobe. In this clinical context, this was consistent with alveolar haemorrhage.

References

[1] Boyd LJ. A study of four thousand reported cases of aneurysm of the thoracic aorta. Am J Med Sci. 1924; 168: 654-663.

[2] Piciche M, De Paulis R, Chiariello L. A review of aortopulmonary fistulas in aortic dissection. Ann Thorac Surg. 1999; 68: 1833-6.

[3] Mukadam M, Barraclough J, Riley P, et al. Acquired aorto-pulmonary artery fistula following proximal aortic surgery. Interact Cardiovasc Thorac Surg. 2005; 4: 388-90.

[3] Maeder MT, Wobler T, Kunzli A et al. Aortopulmonary fistula occurring 4 years after replacement of the ascending aorta. Ann Thorac Surg. 2006; 81: e18-e20.

[4] Ferrari G, Anastasio G, Bianchi M et al. Aortopulmonary fistula after a modified bentall procedure. J Heart Valve Dis. 2012; 21: 505-508.

[5] Wakefield BJ, Winter D, Alfirevic A. Staged repair of an aortopulmonary fistula from a large ascending aortic pseudoaneurysm: the role of transesophageal echocardiography. J Cardiothorac Vasc Anesth. 2015. doi: 10.1053/j.jvca.2015.11.022. [Epub ahead of print].

[6] Coserria F, Mendez A, Moruno A, et al. Percutaneous closure of iatrogenic aortopulmonary fistula using the Amplatzer Septal Occluder. Rev Esp Cardiol. 2014: 67: 228-229.

Dr. John Dreisbach, Glasgow Royal Infirmary

Introduction

The term acute aortic syndrome covers a spectrum of life-threatening emergency conditions of the thoracic aorta, including dissection, intramural haematoma and penetrating atherosclerotic ulcer. The potential acute complications are severe and diverse. The clinical manifestations are often non-specific and overlap significantly with other more common conditions requiring essentially the opposite treatment, most frequently acute coronary syndrome and pulmonary embolism. The best chances of survival depend on a rapid and accurate diagnosis (or indeed exclusion), usually by CT angiography and ideally cardiac-gated to minimise motion artifact.

Questions

Review the single image below (a coronal-oblique reconstruction of a CT angiogram) and address:

1. The type of acute aortic syndrome present
2. The Stanford classification
3. The major complication that has occurred
4. The signs that this major complication is life-threatening

Answers

    1. Acute intramural haematoma of the ascending aorta

There is an area of eccentric high-attenuation lining the wall of the ascending aorta, without discernible enhancement, consistent with an acute intramural haematoma.

    2. Stanford type A

The Stanford classification of aortic dissections aids decision-making for management and also broadly applies to intramural haematomas. Type A dissections involve the ascending aorta and should be managed surgically whereas type B dissections classically commence distal to the left subclavian artery and should be managed medically.

The Stanford classification system is not without many important exceptions and caveats, but is generally useful and routinely employed in both clinical practice and research.

    3. Large haemopericardium

There is a large pericardial collection of high attenuation consistent with acute haemopericardium, in this case due to rupture of the intramural haematoma of the ascending aorta.

Haemopericardium is the commonest complication of both type A aortic dissections and intramural haematomas and the most frequent cause of death in the acute setting, the mechanism of which is described below.

    4. Cardiac tamponade (also known as pericardial tamponade), in this case evidenced by a large volume of relatively undiluted intravenous contrast material in a dependent position within the hepatic veins of the right liver lobe

The accumulation of fluid (in this case haemorrhage) into the pericardial sac, which is lined by a stiff fibrous capsule, transmits pressure onto the underlying heart. This can cause compression and reduced filling of the cardiac chambers, resulting in reduced cardiac output and obstructive shock.

The slow accumulation of fluid may allow time for the pericardium to stretch and accommodate relatively large-volume effusions before causing hemodynamic compromise. However, only a small volume (100-200 ml) of rapidly accumulating pericardial fluid may be required to produce obstructive shock. Unfortunately this patient suffered the worst of both – the rapid accumulation of a large pericardial collection.

In this patient, intravenous contrast was injected into an upper limb vein and undiluted contrast is seen in transit in the SVC. A large volume of undiluted intravenous contrast has travelled down the SVC, bypassed the right atrium, refluxed down into the IVC, and produced a striking appearance by accumulating in a dependent position within the hepatic veins and venous tributaries of the right liver lobe. The reflux of intravenous contrast into the IVC and dilated hepatic veins are key CT signs that the right heart is failing to fill with venous return and in this case represents severe cardiac tamponade at the time of the examination.

References

1. Multidetector CT of aortic dissection: a pictorial review. McMahon MA, Squirrell CA. RadioGraphics 2010;30(2):445–460. http://pubs.rsna.org/doi/full/10.1148/rg.302095104

1. Recommendations for accurate CT diagnosis of suspected acute aortic syndrome (AAS)—on behalf of the British Society of Cardiovascular Imaging (BSCI)/British Society of Cardiovascular CT (BSCCT). Varut Vardhanabhuti, Edward Nicol, Gareth Morgan-Hughes, Carl A Roobottom, Giles Roditi, Mark C K Hamilton, Russell K Bull, Franchesca Pugliese, Michelle C Williams, James Stirrup, Simon Padley, Andrew Taylor, L Ceri Davies, Roger Bury, and Stephen Harden. The British Journal of Radiology 2016 89:1061. http://www.birpublications.org/doi/abs/10.1259/bjr.20150705