Category: Image of the Month

The Consequence of a Nasty Fall

Authors:

Michelle L.T. Wong and Linda Turner.

Affiliations:

Department of Radiology, Maidstone and Tunbridge Wells NHS Trust, United Kingdom.

Case Report:

A previously fit and well lady presented to the Accident & Emergency (A&E) Department after a fall down a flight of stairs. On initial assessment, she was found to be hypoxic with profound lactic acidosis.

An initial chest radiograph demonstrates blunting of the left costophrenic angle with a change in the mediastinal contours (Figure 1) when compared to a previous chest radiograph performed seven years ago (Figure 2). A computed tomography (CT) aortogram was subsequently performed which demonstrates a thoracic aortic dissection flap, mediastinal haematoma and multiple rib fractures (Figures 3 and 4).

The diagnosis of traumatic acute aortic sub-adventitious tear with pseudoaneurysm formation was made. The findings were relayed urgently to the trauma and A&E team. The patient was transferred to the regional tertiary centre for further management and treatment.

Figure 1: Portable chest radiograph demonstrates blunting of the left costophrenic angle with a subtle change in the mediastinal contours when compared to a previous radiograph seven years.

Figure 2: A plain chest radiograph of the same patient that was performed seven years ago as comparison.

Figure 3: Single axial slice of the thorax from the CT aortogram that demonstrates the aortic tear with extensive mediastinal haematoma. There are associated bilateral pleural effusions.

Figure 4: Single coronal slice of the thorax (reformatted image) demonstrating the aortic tear at the level of the aortic isthmus.

Questions:

1. Where is the commonest anatomical location for traumatic aortic injuries?

1. Arch of the Aorta
2. Aortic isthmus
3. Root of aorta
4. Descending thoracic aorta
5. Ascending thoracic aorta

Answer: B

The aortic isthmus is the commonest location for lesions (approximately 90% of all cases of patients who have been subjected to thoracic trauma). Its relatively immobile position within the thorax due to its attachment by the ligamentum arteriosum explains the reason for this site being involved in many injuries.

    2. What is the main purpose of a chest radiograph?

1. To detect rib fractures
2. To detect pleural effusions
3. To detect mediastinal haematoma
4. To detect lung contusions
5. To assess cardiac size

Answer: C

The main purpose is to detect a mediastinal haematoma that would indicate considerable aortic trauma. Mediastinal enlargement of more than 8cm and / or 25% of the width of the thorax is most frequently observed, but is not the most sensitive sign. The diagnosis must be suspected if there is any abnormality whatsoever of the aortic arch or opacification of the space between the aorta and the pulmonary artery.

   3. How many grades of traumatic aortic injuries are there?

1. 5
2. 4
3. 3
4. 2
5. 1

Answer: C

Grade 1 disruption corresponds to rupture of the tunica intima and a part of the tunica media which results in a hypodense line within the aortic lumen on CT. Grade 2 disruption is a sub-adventitious rupture involving the whole of the tunica intima and media with only the tunica adventitia (a distensible and watertight structure) retaining the blood, thus forming a pseudoaneurysm. Grade 3 lesions involve ruptures of all three tunica layers of the aorta and therefore produces an extravasation of contrast agent, the aortic blood only being retained by the mediastinal fat.

References:

1. Cullen E.L., Lantz E.J., Johnson C.M. and Young P.M. Traumatic aortic injury: CT findings, mimics and therapeutic options. Journal of Cardiothoracic Diagnosis and Therapy. 2014; 4(3): 238 – 244.
2. Heneghan R.E., Aarabi S., Quirogi E., Gunn M.L et al. Call for a new classification system and treatment strategy in blunt aortic injury. Journal of Vascular Surgery. 2016; 64(1): 171 – 176.
3. Yahia A.A., Bouvier A., Nedelcu C., Urdulashvili M. et al. Imaging of thoracic aortic injury. Diagnostic and Interventional Imaging. 2015; 96(1): 79 – 88.

Authors:

Robert W. Foley, Sophie Glenn-Cox, Benjamin J. Hudson, Jonathan C. L. Rodrigues.

Affiliations:

Department of Radiology, Royal United Hospitals Bath NHS Foundation Trust, Bath, United Kingdom.

Case Report

A 36-year-old man presented to the emergency department with acute onset of severe chest pain radiating to his back. There were no high-risk exam features or a pre-existing high-risk condition. His heart rate was 40 beats per minute and regular. An urgent ECG-gated CT angiogram of the aorta was performed to exclude an acute aortic syndrome.

A retrospective spiral ECG-gated bolus-tracked acquisition (Siemens Edge, 50ml Iomeron® 350 at 5ml/sec) was performed with tube current modulation, maximum dose at 70% R-R interval and automatic best diastolic reconstruction.

The CT demonstrated a linear band of low attenuation in the ascending aorta (Figure 1).

Figure 1

The on-call general radiologist sought a specialist opinion regarding the possibility of an aortic dissection flap. However, on review of the coronal images, the linear artefacts were repeated at regular intervals along the z-axis (Figure 2).

Figure 2

The original image demonstrating the linear artefact in the ascending aorta was reconstructed at 76% of the RR interval. The cardiac radiologist suspected interpolation artefact and generated additional reconstructions after ECG editing, reconstructed at 85% of the RR interval, which significantly reduced this artefact (Figure 3).

Figure 3

Data is interpolated to generative transverse reconstructions from helically acquired CT data. It assumes a photon will experience the same attenuation if it originates from any given location or 180° from that given location. However, in reality there is slice broadening, dictated by how far the CT gantry moves during a single 180° CT beam turn. Our case highlights a rare ECG-gated artefact, which also requires acquisition to be synchronised with the R-R interval. Owing to such a slow heart rate (40 beats per minute), there was insufficient data acquired during the prolonged time between R-waves and greater distance travelled by the CT gantry per heart beat in the z-axis. The regular banding artefact resulted from interpolated data between the previous and next data points acquired by the CT during consecutive R waves [1].

The benefits of ECG-gating vastly outweigh the disadvantages of non-gated techniques when acquiring CT for suspected acute aortic syndrome. However, we present a rare case of an ECG-gating specific artefact resulting from a very low heart rate. We hope that this raises the awareness of this interpolation artefact in the setting of a very low heart rate and highlights how ECG editing can help reduce the impact and thus hopefully will mitigate against potential misinterpretation, which may have important implications for the patient.

Multiple Choice Questions

1. Which of the following is not considered within the spectrum of Acute Aortic Syndrome?
   1. Penetrating atherosclerotic ulcer
   2. Type A aortic dissection
   3. Ruptured abdominal aortic aneurysm
   4. Type B aortic dissection
   5. Intramural haematoma
2. According to the BSCI/BSCCT Guidelines for CT diagnosis of acute aortic syndrome [2], which of the following is not a high risk examination feature for acute aortic syndrome?
   1. Systolic blood pressure deficit
   2. Murmur of Aortic Insufficiency
   3. Focal neurological deficit
   4. Hypertension
   5. Pulse Deficit
3. Which of the following is not a CT artefact that could be encountered when imaging in suspected acute aortic syndrome?
   1. Reverberation Artefact
   2. Pulsation artefact
   3. Interpolation artefact
   4. Breathing artefact
   5. Streak artefact
4. In aortic dissection, which of the following does not help differentiate the true lumen from the false lumen?
   1. The beak sign
   2. The false lumen is usually smaller
   3. Intraluminal thrombosis is more commonly seen in the false lumen
   4. The intimomedial rupture sign
   5. The cobweb sign

Answers

1. c
2. d – Hypotension, or shock, is a high-risk examination feature for acute aortic syndrome. Hypertension is a risk factor that may lead to accelerated premature degeneration of collagen and elastin within the aorta and therefore predispose to the development of acute aortic syndrome.
3. a – Reverberation artefact is encountered in ultrasonography. This artefact is caused by a series of delayed echoes from a strongly reflecting interface. For example, comet-tail artefact can be encountered during echocardiography in patients with prosthetic or calcified valves.
4. b – The false lumen is usually larger than the true lumen, due to increased pressure within the dissection flap. In the beak sign, there is an acute angle between the dissection flap and the outer wall of the false lumen. The intimomedial rupture sign occurs when the entry point of a dissection flap points towards the false lumen, representing the flow of blood from true lumen to false lumen. The cobweb sign is caused by thin strands of unseparated tissue between the intima and media and can be seen within the false lumen.

References

1. Kang J-W, Do K-H, Chung J-Y, Cho HJ, Seo JB, Lim T-H (2010) Concept of minimal heart rate for each pitch value to avoid interpolation artifact when using dual-source CT: a phantom study. Int J Cardiovasc Imaging 26:103–109

2. Vardhanabhuti V, Nicol E, Morgan-Hughes G, et al (2016) 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). Br J Radiol 89:20150705

Haemoptysis and an unusual ‘lung mass’

Tom Foster ¹, Michelle C Williams ², Peter Maclean ¹

1. Department of Radiology, Western General Hospital, Edinburgh
2. University of Edinburgh, Edinburgh

A young male patient presented to his GP after an episode of haemoptysis. He reported a 1 month history of dyspnoea, non-productive cough and intermittent fever. Initial chest X-ray (Figure 1) showed a 3.5 cm diameter rounded opacity in the right lower zone, with further patchy opacification in the left lower zone. This was initially reported as likely infective consolidation, but the clinical team’s differential diagnosis also included pulmonary embolus or malignancy.

Figure 1. 3.5 cm rounded opacity in the right lower zone (red asterisk), with further patchy opacification in the left lower zone (yellow asterisk).

Further questioning identified a history of weight loss and night sweats. Therefore a CT chest / abdomen / pelvis was performed.

Arterial phase imaging through the lower lungs (Figure 2) showed a 3.5 cm contrast-filled lesion in keeping with a pulmonary artery aneurysm arising from a segmental branch of the right lower lobe pulmonary artery. Lung windows show some surrounding ground-glass change (Figure 3). Coronal MIP imaging (Figure 4) demonstrates a right lower lobe segmental artery pulmonary aneurysm clearly, with contrast within the lesion seen in continuity with the pulmonary trunk. A pulmonary vein is seen adjacent to the lesion, draining to the right atrium. There were a number of other areas of patchy areas of opacification located peripherally in the lungs (Figure 5). Small areas of pulmonary thrombus were seen proximal to some of these lesions. These were therefore felt to represent a mixed picture of multiple small areas of pulmonary haemorrhage, sub-segmental pulmonary emboli and focal areas of pulmonary infarction.

CT imaging of the abdomen (Figure 6) showed multiple wedge-shaped low-attenuation areas throughout both kidneys in keeping with perfusion abnormalities. There was however no other evidence of aneurysm or other significant findings in the abdomen or pelvis.

Figure 2. Axial CT slice through a contrast-filled lesion (red asterisk) in the right lower lobe on arterial-phase imaging.

Figure 3. Cropped and magnified view of the lesion on lung window showing surrounding ground-glass opacification.

Figure 4. Coronal MIP view of the aneurysm (red asterisk) of a right lower lobe segmental branch artery. The artery proximal to the aneurysm is seen superiorly (pink asterisk) and a draining pulmonary vein is seen inferiorly (green asterisk).

Figure 5. There were multiple other pulmonary abnormalities (asterisks), all located peripherally within the lungs. Some of these (red asterisk) had pulmonary thrombus proximal to them and were felt to represent pulmonary infarction.

Figure 6. An oblique coronal view through the kidneys, with multiple wedge shaped low attenuation areas bilaterally (arrowed).

The impression at this stage was that findings may represent an underlying vasculitic process such as granulomatosis with polyangiitis (previously called Wegener’s granulomatosis), Takayasu’s arteritis or Behçet’s disease. After discussion with interventional radiology and cardiothoracic surgery, the patient underwent right lower lobe basal segmentectomy.

Histopathology of the resected lung demonstrated a necrotising inflammatory process associated with areas of pulmonary infarction and focal lymphocytic vasculitis of branches of the pulmonary artery. Findings were in keeping with either Behçet’s disease or Hughes-Stovin syndrome (a rare auto-immune condition similar to Behçet’s characterised by thrombophlebitis and pulmonary/bronchial aneurysms). The patient reported oral ulcers, but no other classical findings of Behçet’s disease, therefore the final diagnosis was felt to be either atypical Behçet’s disease or Hughes-Stovin syndrome.

Discussion

Behçet’s disease is a multi-system autoimmune disease of unknown aetiology. It is more common in males and highest incidence in individuals aged 20-30, particularly those in the Middle East and Japan ¹. Behçet’s Disease is likely the result of a complex interplay between various genetic and environmental factors (including certain infections and their antigens) and has been associated with HLA B51 and Factor V Leiden mutation ².

Behçet’s disease is classically characterised by the triad of oral ulceration, genital ulceration and ocular lesions. As well as the aforementioned triad of symptoms, Behçet’s is a multi-system disorder and has the potential to involve the cardiovascular system (as in this case), the lungs, the gastrointestinal tract, genitourinary tract, the central nervous system, the skin and joints ³.

Diagnosis of Behçet’s Disease can be difficult and therefore international criteria have been developed for this purpose. The International Criteria for Behçet’s Disease (ICBD) and associated scoring is as follows, with a score of ≥4 being diagnostic for Behçet’s ⁴:

• Ocular lesions – 2 points
• Genital aphthosis – 2 points
• Oral aphthosis – 2 points
• Skin lesions – 1 point
• Neurological manifestations – 1 point
• Vascular manifestations – 1 point
• Positive pathergy test – 1 point

The patient in this case would have scored 3 points, being positive for oral aphthous ulcers and vascular manifestations. Pathergy refers to an exaggerated reaction to skin injury from minor trauma (such as a needlestick) and this patient was noted to develop thrombophlebitis at a number of peripheral venous cannula sites but had no definite evidence of pathergy.

Treatment and prognosis is variable, with some patients’ disease resolving spontaneously, others requiring long courses of corticosteroid therapy and other’s requiring management with surgery or interventional radiology. If the disease does resolve it also has the potential to recur at a later date ⁵.

Hughes-Stovin syndrome is a multi-system inflammatory condition characterised by pulmonary/bronchial artery aneurysm in the setting of thrombophlebitis. Radiological findings and histopathological findings can be similar or sometimes indistinguishable from Behçet’s Disease, with the result that the term ‘incomplete Behçet’s Disease’ has been used to describe Hughes-Stovin Syndrome. Some authors postulate that Hughes-Stovin syndrome is in fact Behçet’s Disease ⁶ and even without the other ICBD criteria that it should be treated as such.

Questions

1. Which human leukocyte antigen (HLA) type is associated with development of Behçet’s Disease?
   1. HLA-B27
   2. HLA-B47
   3. HLA-B51
   4. HLA-DR3
   5. HLA-DR4

2. What is the most common symptom in patients presenting with Behçet’s Disease

1. 1. Genital aphthous ulcers
   2. Ocular manifestations (e.g. uveitis or retinal vasculitis)
   3. Oral aphthous ulcers
   4. Joint manifestations (arthralgia or arthritis)
   5. Vascular manifestations

3. Behçet’s Disease is a vasculitis that can affect large, medium and small vessels. Which of these             vasculitides is classically considered a large vessel vasculitis?

1. 1. Eosinophilic granulomatosis with polyangiitis
   2. Granulomatosis with polyangiitis
   3. IgA vasculitis
   4. Kawasaki disease
   5. Takayasu’s arteritis

Answers

1. C.

HLA-B51 is associated with the development of Behçet’s Disease ². HLA-B27 is associated with ankylosing spondylitis. HLA-B47 is associated with congenital adrenal hyperplasia due to 21-hydroxylase deficiency. HLA-DR3 is associated with Sjogren’s syndrome, autoimmune hepatitis and type 1 diabetes. HLA-DR4 is associated with type 1 diabetes and rheumatoid arthritis ⁷.

2. C.

Oral aphthous ulcers are the most common symptom in patients presenting with Behçet’s Disease. When creating the International Criteria for Behçet’s Disease (ICBD), 1278 patients with Behçet’s Disease from 27 countries were identified. 98% of these had oral aphthous ulcers, 74% had genital aphthous ulcers, 55% had ocular manifestations, 51% had joint manifestations and 19% had vascular manifestations ⁴.

3. E.

Takayasu’s arteritis is a large vessel vasculitis. Eosinophilic granulomatosis with polyangiitis (previously Churg-Strauss syndrome), granulomatosis with polyangiitis (previously Wegener’s granulomatosis) and IgA vasculitis (previously Henoch-Schönlein purpura) are all small vessel vasculitides. Kawasaki disease is a medium vessel vasculitis.

_______________________

References

1. Kontogiannis V, Powell RJ. Behçet’s disease. Postgrad Med J. 2000 Oct; 76(900): 629–637.
2. Marshall SE. Behçet’s disease. Best Pract Res Clin Rheumatol. 2004 Jun;18(3):291-311.
3. Davatchi F, Chams-Davatchi C et al. Behçet’s disease: epidemiology, clinical manifestations, and diagnosis. Expert Rev Clin Immunol. 2017 Jan;13(1):57-65.
4. International Team for the Revision of the International Criteria for Behçet’s Disease (ITR-ICBD).The International Criteria for Behçet’s Disease (ICBD): a collaborative study of 27 countries on the sensitivity and specificity of the new criteria. J Eur Acad Dermatol Venereol. 2014 Mar;28(3):338-47.
5. Cheon JH, Kim WH. An update on the diagnosis, treatment, and prognosis of intestinal Behçet’s disease. Curr Opin Rheumatol. 2015 Jan;27(1):24-31.
6. Erkan D, Yazici Y et al. Is Hughes-Stovin syndrome Behçet’s disease? Clin Exp Rheumatol. 2004 Jul-Aug;22(4 Suppl 34):S64-8.
7. Kumar V, Robbins SL. Table 5-7. Robbins Basic Pathology (8th edition). 2007. Philadelphia: Elsevier Saunders.

What happens when a patient’s aorta falls off?

Dr M. Spurr, Dr A. Thorpe, Mr U. Benedetto and Dr M. Hamilton, Bristol Royal Infirmary.

A 41 year old man presented to a District General Hospital after collapsing three times at home. He had been experiencing headaches, double vision, and fever in the week prior. On admission the patient had raised inflammatory markers, a raised temperature and was tachycardic. The patient had a dental abscess one week before the symptoms started.

Three years previous to this admission the patient had his native bicuspid aortic valve replaced with a mechanical aortic valve and an ascending aortic replacement due to infective endocarditis (figure 1).

A transoesophageal echocardiogram (TOE) was performed which showed a large vegetation on the aortic valve replacement and suspicion of an aortic root abscess adjacent to the non-facing sinus (Figure 2). The anatomy was considered indeterminate on TOE. CT was initially turned down as it was thought it would not be diagnostic because of artefact from the aortic valve replacement. The patient was transferred to a tertiary hospital and a gated aortic angiogram CT was performed. The CT showed subtotal dehiscence of the aortic root from the ascending aorta with a large false aneurysm (see figures 3 and 4). The coronary insertion and proximal suture line of the ascending aortic replacement allowed the correct interpretation of the anatomy. While CT is inferior to TOE for showing vegetations, it is the test of choice if there is indeterminate anatomy or incompletely imaged aortic root pathology.

Figure 1 – Coronal oblique reformat of an aortic CT (non-gated helical). It is a baseline image from 2015 showing a post aortic valve and ascending aorta replacement

Key for figure 1

Star – sinus of Valsalva. Arrow heads – pledgets marking the proximal and distal suture lines of the ascending aortic replacement. Arrow – ascending aortic replacement.

Figure 2 – Initial transoesophageal ultrasound scan demonstrating an uncertain aortic contour

Key for figure 2

Arrow – bottom end of tube graft. Stars – “2” sinuses of Valsalva. The one closest to the aortic valve proved to be a false aneurysm. Arrowhead – aortic valve vegetation. Oval – soft tissue aortic root thickening.

Figure 3 – Reconstructed short axis CT image of the aortic root showing the “pseudo” sinus of Valsalva (star) as a large irregular cavity around the AVR

Figure 4 – Sagittal oblique ECG gated CT (systole) of the aortic root and ascending aorta

Key for figure 4

Stars – “2” sinuses of Valsalva. The one closest to the aortic valve proved to be the false aneurysm.

The patient was taken to theatre for emergency revision surgery. The aortic graft was incised and the root exposed. Direct visualisation confirmed rupture of the left sinus and an abscess associated with the right and non-facing sinus.

The previously inserted aortic graft was removed. A homograft conduit was inserted into the left ventricular outflow tract and connected distally just above the origin of coronary arteries. A tissue valve prosthesis was then implanted inside the homograft conduit. To finish a new vascular graft extending up to the proximal aortic arch was inserted.

Question 1

Which of the following statements best describes the role of CT with regards to imaging of the aortic root?

1. TOE is the modality of choice when there is indeterminate aortic root anatomy.
2. CT is the modality of choice to visualise an aortic valve vegetation.
3. CT has no role in imaging of the aortic root.
4. CT is a good alternative to visualise indeterminate aortic root anatomy if TOE is unavailable.
5. CT is the test of choice for imaging indeterminate aortic root anatomy.

Answer – 5

As demonstrated by this case, although CT is inferior to TOE for showing vegetations, it is the test of choice if there is indeterminate anatomy or incompletely imaged aortic root pathology.

Question 2

Which of the following statements is correct regarding imaging of a patient with an AVR?

1. An AVR is an absolute contraindication for CT imaging of the aortic root.
2. CT should be avoided when a patient has an AVR as artefact will result in nondiagnostic images.
3. Only a tissue valve prosthesis should be imaged with CT.
4. Useful information can be obtained on CT despite artefact for an AVR.
5. AVRs cause phase wrap-around artefact on CT.

Answer – 4

Useful information can still be attained despite artefact from a metallic AVR. Phase wrap-around artefact is a feature of MRI.

Question 3

What is the most common causative organism in endocarditis?

1. Staphylococcus Aureus
2. Streptococcus Viridians
3. Streptococcus Mutans
4. Escheriachia Coli
5. Streptococcus Pneumoniae

Answer – 1 

Question 4

What percentage of patients with prosthetic valves will develop endocarditis?

• 5%
• 1%
• 5%
• 19%
• 28%

Answer – 1

Approximately 5% of patients with prosthetic valves develop endocarditis. Involvement of the mitral valve prostheses is more frequent than that of aortic valve prostheses. (2)

References

• Murdoch DR, Corey GR, Hoen B et al.Clinical presentation, etiology, and outcome of infective endocarditis in the 21st century: the International Collaboration on Endocarditis–Prospective Cohort Study. Archives of Internal Medicine. 2009;169(5):463–473.
• Mylonakis E, Calderwood SB. Infective endocarditis in adults. New England Journal of Medicine. 2001;345(18):1318–1330.

Authors: Tom Foster ¹, Michelle C Williams ², Marialena Gregoriades ¹

1. Department of Radiology, Western General Hospital, Edinburgh

2. University of Edinburgh, Edinburgh

Case history:

An elderly patient was admitted with a several week history of fatigue and reduced mobility. They had previously undergone tissue AVR and CABG.

On examination they were noted to have splinter haemorrhages, Osler’s nodes and elevated inflammatory markers. This raised the suspicion of infective endocarditis (IE).

However, blood cultures were all negative and trans-thoracic echo did not demonstrate any vegetations. Trans-oesophageal echo was felt not to be indicated given negative blood cultures. A non-gated contrast enhanced computed tomography (CT) scan of the chest, abdomen and pelvis was performed to investigate infection of unknown origin.

CT images identified a 45mm filling defect extending from the aortic valve into the lumen of the ascending aorta (Fig. 1). The aorta was thick walled in keep with mural oedema, suggestive of aortitis. Anteriorly in the mediastinum, anterior to the aorta and posterior to the septum there was a separate walled off, enhancing collection.

Figure 1. Coronal (left) and axial (right) CT images showing large filling defects within the ascending thoracic aorta (marked *). An enhancing collection is seen in the anterior mediastinum on the axial view (marked **).

The presence of vegetations arising from the aortic valve was subsequently confirmed on trans-oesophageal echo (Fig. 2).

Figure 2. Trans-oesophageal echo showing large vegetations adjacent to the aortic valve (marked with *).

The patient was started on broad spectrum antibiotics and intravenous antifungal treatment. Further investigation with multiple blood cultures subsequently demonstrated fungal infection.

Discussion:

Infective endocarditis is infection of the inner lining of the heart, usually affecting the heart valves, with an incidence rate of approximately 1.7-6.2 cases per 100,000 patient years ^[1]. Despite being relatively uncommon, it is important to recognise early due to high rates of morbidity and mortality.
The most frequent aetiology is a bacterial infection, with Staphylococcus aureus and viridans group streptococci being the most common causative organisms. Other bacteria associated with endocarditis include coagulase-negative Streptococci and Enterococci, with a number of other organisms seen less frequently (such as the ‘HACEK’ group of organisms). Fungal endocarditis is less common, with Candida and Aspergillus species being the most frequent fungi identified.

Clinical presentation is variable and often linked to the underlying causative organism, with for example infective endocarditis with Staphylococcus aureus generally causes an acute presentation (<2 weeks) when compared to viridans group streptococci which are generally associated with a more subacute presentation (weeks to months). Signs and symptoms of infective endocarditis include:

• Fever and constitutional symptoms (e.g. fatigue, malaise, etc.) – these are seen in the vast majority of patients.
• Heart murmur – new or changing; this finding causes particular concern when associated with prosthetic valves.
• Immunological phenomena (e.g. Osler’s nodes on the hands/feet, Roth’s spots on the retina).
• Vascular phenomena (e.g. Janeway lesions on the hands/feet, septic emboli, splinter haemorrhages).

The modified Duke criteria (2004) can be used to diagnose infective endocarditis by assessing whether certain pathological or clinical diagnostic criteria are met. Clinical criteria involve elements of the patient history (e.g. predisposing factors), examination findings (e.g. pyrexia, Osler’s nodes and Janeway lesions), blood culture results and imaging findings. Imaging is most often in the form of echocardiography (both transthoracic and transoesophageal) but other modalities such as CT may be useful, as in this case. The European Society of Cardiology have more recently produced new modified diagnostic criteria in 2015 ^[2] recognise the value of cardiac CT and nuclear imaging in diagnosis.

This particular case demonstrates some of the difficulties in diagnosing infective endocarditis. Transthoracic echo in particular is limited as even large vegetations may not be identified. Prosthetic valves in particular can be challenging to image with transthoracic echo as metal artefact may obscure vegetations. It is therefore important to not be falsely reassured by negative blood cultures and a normal transthoracic echo.

While transoesophageal echo is the ‘gold standard’ imaging test for suspected infective endocarditis, this situation highlights the potential value of CT in the diagnosis.  Some patients may be too frail or not able to tolerate transoesophageal echo. Large vegetations may be identified on non-gated imaging such as in this case, but for more subtle cases gated CT may be required. Many CT scans are performed to assess sepsis of unknown origin, therefore the heart should be an important review area in such cases.

It is also important to remember fungal endocarditis as a potential source of culture-negative endocarditis. Fungal endocarditis is a rare condition but is particularly associated with immunocompromise, long term broad-spectrum antibiotic use, central venous catheters and previous cardiac surgery ^[3]. It is becoming increasingly common in the intensive care setting and a high index of suspicion for fungal endocarditis is important in patients in this setting who fail to respond to antibiotic therapy ^[2]. Embolic events are common in fungal endocarditis, more so than in bacterial endocarditis and may complicate diagnosis and subsequent management. One literature review showed that over half of cases had evidence of embolic events at initial presentation ^[4].

Questions:

1. What is the most common causative organism in fungal endocarditis?
   1. Aspergillus
   2. Candida
   3. Cryptococcus
   4. Histoplasma
   5. Tricosporon
2. What is the approximate mortality rate of fungal endocarditis?
   1. 1-2 %
   2. 10 %
   3. 25 %
   4. 30 %
   5. >50 %

3. Which of these factors is not recognised as a predictor of poor outcome in infective endocarditis?
   1. Large vegetations
   2. Low left ventricular ejection fraction
   3. Non-HACEK Gram-negative bacilli as the causative organism
   4. Premature mitral valve closure
   5. Viridans group streptococci as the causative organism

Answers:

1. b- Candida spp is the most common causative organism, being responsible for roughly a quarter to a half of cases of fungal endocarditis, Aspergillus spp being responsible for approximately another quarter and other fungi including Histoplasma species making up the remaining cases ^[5].

2. e- Fungal endocarditis is a serious condition and fatal in approximately 50 % of cases ^[2]. This is for a number of reasons:

• Difficulties in establishing a diagnosis – blood cultures are often negative. Clinical manifestations are similar to bacterial endocarditis and therefore important to consider fungal endocarditis in cases of infective endocarditis that do not respond to antibiotic therapy. Diagnosis is made post-mortem in a large number of cases ^[6].
• Difficulty in treatment – treatment requires potent antifungal agents (such as amphotericin B and caspofungin) and surgical management (if patient is fit) ^[2]. Treatment success rate with medical therapy alone is low, and risk of recurrence is high. Specialist local microbiologist input is vital.
• Associated comorbidities – fungal endocarditis often occurs in those with other underlying medical problems, such as those who are immunosuppressed.
• Lack of awareness – fungal endocarditis perhaps is less well recognised than bacterial endocarditis.

3. e- Viridans group streptococci are associated with a more subacute presentation and better prognosis. All the other answers are predictors of poor outcome ^[2]. Premature mitral valve closure is a feature of elevated left ventricular diastolic pressure.

References:

 [1] Beynon RP, Bahl VK, et al. Infective endocarditis. BMJ 2006; 333:334-9.

[2] Habib G, Lancellotti P, ESC Scientific Document Group et al. 2015 ESC Guidelines for the management of infective endocarditis: The Task Force for the Management of Infective Endocarditis of the European Society of Cardiology (ESC). European Heart Journal 2015; 36(44): 3075–3128.

[3] Pierrotti LC, Baddour LM. Fungal endocarditis, 1995-2000. Chest 2002; 122(1): 302–10.

[4] Kalokhe AS, Rouphael N et al. Aspergillus endocarditis: a review of the literature. Int J Infect Dis 2010; 14: 1040–1047.

[5] Ellis ME, Al-Abdely H, et al. Fungal endocarditis: evidence in the world literature, 1965-1995. Clin Infect Dis 2001; 32:50.

[6] Seelig MS, Speth CP et al. Patterns of Candida endocarditis following cardiac surgery: Importance of early diagnosis and therapy (an analysis of 91 cases). Prog Cardiovasc Dis 1974; 17(2):125-60.

Magnetic resonance angiography using feraheme (ferumoxytol)

Marwa Daghem, Michelle C Williams

Centre for Cardiovascular Science, University of Edinburgh, UK. 

Case

A 66 year old male with a background of hypertension and ankylosing spondylitis was admitted to the local cardiac centre with acute chest pain and a raised troponin. Electrocardiogram confirmed sinus rhythm with lateral T waves change (V4 – V6, I and aVL). He was treated for an acute coronary syndrome and subsequently had an inpatient invasive coronary angiogram (ICA). ICA confirmed the presence of three-vessel coronary artery disease with an occluded right coronary artery, moderate disease in the circumflex artery, and a diffusely diseased LAD with a moderate proximal lesion and a tight stenosis in the mid-vessel. A surgical revascularisation strategy is planned.

He agreed to participate in a research study and underwent magnetic resonance angiography using ultrasmall superparamagnetic particles of iron oxide (USPIO). Using a 3 Tesla scanner magnetic resonance coronary angiography (MRCA) was performed using 4 mg/kg ferumoxytol.

Figure 1 shows images of the left anterior descending coronary artery from computed tomography, USPIO MRCA and invasive coronary angiography. Mild non obstructive mixed plaque is seen in the proximal vessel (grey arrow). In the mid vessel there is a non-calcified plaque showing a severe stenosis (white arrow).   

Figure 2 shows images of the right coronary artery from USPIO MRCA and invasive coronary angiograph. The right coronary artery is occluded (grey arrow). 

Figure 3 shows (A) short axis, (B) three chamber, (C) four chamber views of the heart showing left ventricle (LV), right ventricle (RV), right atrium (RA), left atrium (LA), left atrial appendage (LAA), pulmonary artery (PA), aorta (Ao), aortic valve (AV), pulmonary valve (PV), mitral valve (MV), and tricuspid valve (TV).

Discussion

USPIO MRCA offers an alternative to gadolinium-based MRCA. This may be useful for patients in whom gadolinium is contraindicated, such as patients with renal impairment. USPIO MRCA provides excellent identification of the presence and location of coronary arteries, down to the distal vessels and small diagonal branches. Stenosis severity can also be assessed, but with reduced accuracy compared to computed tomography coronary angiography and invasive coronary angiography.

Questions

Question 1

Based on the ECG changes and the imaging findings what vessel/segment is the likely culprit?

A. Right Coronary Artery (RCA)

B. Circumflex Artery (Cx)

C. Proximal Left Anterior Descending Artery (LAD)

D. Mid Left Anterior Descending  Artery (LAD)

Answer D.

The tight mid Left Anterior Descending Artery stenosis is the lesion that is most likely to account for this acute presentation. There is retrograde filling of the RCA suggesting this is a chronic occlusion. The LCX has only moderate disease and would not account for the ECG changes. If the proximal LAD was the culprit you would also expect to see changes in the anterior pre-precordial leads.

Question 2

Magnetic resonance coronary angiography can be performed with which of the following?

1. Gadolinium enhanced sequences
2. USPIO enhanced sequences
3. Non contrast sequences
4. All of the above

Answer D.

MRCA can be performed with gadolinium, USPIO and non-contrast sequences, although gadolinium enhanced sequences are the most widely available.

Question 3

Current indications for magnetic resonance coronary angiography include

1. Assessment of anomalous coronary arteries
2. First investigation for acute chest pain
3. First investigation for stable chest pain
4. Measurement of fractional flow reserve

Answer A.

MRCA is an option for the assessment of coronary anomalies and aneurysms, particularly in younger patients.

Question 4

Which valves have three cusps?

1. Aortic valve
2. Aortic and pulmonary valve
3. Mitral valve
4. Aortic, pulmonary and tricuspid valve

Answer D.

Acknowledgements

This research was funded by the Academy of Medical Sciences.

When a curry gives you more than heartburn: A rare cause of myocardial infarction. 

Dr. S. Ahmed, Dr. A. Appaji, Dr. A. Large, Dr. S. Duckett Department of Cardiology, Royal Stoke University Hospital, Stoke-on-Trent. 

A fifty-six year old female was admitted to accident and emergency (A&E) with a witnessed collapse at home. She had a background history of recurrent urinary tract infections and an eleven pack year history of smoking. She had diarrhoea and vomiting for two days prior to admission after having a home-cooked curry and recalled feeling dizzy and nauseous with chest discomfort before passing out.

On arrival to A&E, her blood pressure was 88/62 mmHg with symptoms of feeling light-headed and clammy. On examination her jugular venous pressure was elevated, normal heart sounds and bibasal crepitations on chest auscultation. Electrocardiogram (ECG) showed normal sinus rhythm with ST segment depression in leads III, aVF and V4 to V6 with a subsequent troponin rise of > 50000. CXR showed evidence of pulmonary oedema.

A cardiac MRI was performed which showed mild impairment of left ventricular function, a limited basal infero-septal myocardial infarction. An incidental finding of a small (5X8mm) mobile mass was seen in the proximal ascending aorta, fixed to the aortic wall superior to the ST junction and above the RCA origin which was felt to be thrombus. It was dark on the early gadolinium image (image C) and non-enhancing on the late gadolinium (image B).

CT coronary angiography was performed to further assess the coronary arteries which revealed a dissection flap (image D see arrow) causing moderate stenosis at the right coronary artery (RCA) ostium with further mild stenosis caused by a long soft tissue plaque in the proximal vessel. The images and cases were discussed with the interventional cardiology team and conservative management was felt to be the best option.

The patient was discharged with dual antiplatelet therapy for 12 months and an ACE inhibitor, statin and beta blocker. A follow up CT imaging revealed resolution of the RCA ostial dissection flap with no significant stenosis. (image E see arrow)

Discussion:

Spontaneous coronary artery dissection is a rare cause of non-atherosclerotic myocardial infarction with an incidence of 0.1% to 0.4% of all acute coronary syndromes.1 It is more commonly described in young females and known to be associated with fibromuscular dysplasia, connective tissue disease and peri-partum status. Frequently identified triggers include catecholamine release mediated by physical exertion, intense emotional stress and increased abdominal pressures induced by coughing, retching or vomiting.2 Both these mechanisms increase the shearing stress on the coronary artery wall. A conservative approach towards management with standard medical therapy is usually preferred compared to invasive angiography as most cases resolve spontaneously.

References: 

1. Mortensen KH, Thuesen L, Kristensen IB, Christiansen EH. Spontaneous coronary artery dis- section: a Western Denmark Heart Registry study. Catheter Cardiovasc Interv. 2009 Nov 1;74(5):710-7.

2. Saw J, Aymong E, Sedlak T, Buller CE, Starovoytov A, Ricci D, Robinson S, Vuurmans T, Gao M, Humphries K, Mancini GB. Spontaneous coronary artery dissection: association with predisposing arteriopathies and precipitating stressors and cardiovascular outcomes. Circ Cardiovasc Interv. 2014 Oct;7(5):645-55.

Problem Solving using Cardiac CT by Modifying Technique

Dr Ashley Thorpe, Dr Rajiv Singh and Dr Garrett McGann

An 80 year old presented to the emergency department after suffering syncope whilst sat in a chair with no prodromal features. Past medical history included COPD, bronchiectasis and hypothyroidism.

As a result, a transthoracic echocardiogram (TTE) was arranged as an outpatient which demonstrated a mildly dilated left atrium at 60mls and an echogenic structure visualised within the left atrium with a possible attachment to the atrial septum. Colour flow is seen to contour the structure.  (Figure 1A &B)

Question 1: What is the most common cardiac tumor?

1. Lipoma
2. Myxoma
3. Metastases
4. Sarcoma

Answer:

C) Metastases – Metastases are estimated to be 30 times more common than primary cardiac tumors. Common tumors which frequently metastasize to the heart include breast, melanoma and lymphoma. (1)

A CT cardiac angiogram was arranged to further investigate the ultrasound abnormality. A transoesophageal ultrasound was considered, however a CT was chosen due to its less invasive nature. A modified protocol was used to include both a prospective ECG-gated coronary artery study and a 10 second delayed phase.

During the arterial phase there was the impression of a filling defect within a mildly dilated left atrial appendage suspicious for a mass or thrombus. (Figure 1C) The critical phase in this series, the delayed 10 second phase, which showed the filling defect had disappeared suggesting the arterial phase anomaly, was caused by incomplete mixing of contrast. (Figure 1D)

Discussion:

This case highlights the importance of protocoling and making use of a delayed phase to differentiate a pseudo filling defect from true mass or thrombus. In this case the patient avoided further invasive investigation and treatment and any potential morbidity and complications they may bring. It has been shown that using a 2 phase acquisition significantly reduces pseudo filling defect detection when compared to single phase (2) and has a favourable sensitivity, specificity, positive and negative predictive values in detecting true thrombus when compared to the reference standard, trans-oesophageal echo. (3)

Question 2: What percentage of patients who have atrial fibrillation and a recent embolic event are shown to have LAA clot?

1. 10%
2. 15%
3. 20%
4. 30%
5. 50%

Answer:

C)  ≈20%. In a study of 317 patients with AF and a recent embolic event, 21-23% were found on transoesophageal echo to have left atrial appendage clot. (5)

30-40% of strokes have no demonstrable cause. The left atrium and specifically the left atrial appendage has been studied to shed light specifically on cryptogenic stroke. Specific LAA morphologies have been shown to increase the risk of LAA thrombus and stroke. LAA function has also been assessed and poorer function has been linked to LAA thrombus and stroke.   (6)

Question 3: What are common causes of mass mimics on transthoracic echocardiography?

1. Crista terminalis
2. Right ventricular moderator band
3. Atrioventricular groove fat
4. Hiatal hernia
5. All of the above

Answer:

E) The crista terminalis can appears as a hyperechoic structure against the right atrial wall. A thickened right ventricular moderator band can appear as a mass within the right ventricle. Lipomas of the atrioventricular groove can protrude into the atria or the ventricles and appear as an intracardiac mass. A hiatal hernia large enough can impress upon the heart and can cause a pseudomass within the left atrium. (7)

Figure 1: (A) TTE 4 chamber view demonstrating an echogenic structure within the left atrium possibly attaching to the atrial septum. (B)TTE 4 chamber view with colour flow contouring the echogenic structure within the left atrium. (C) Arterial phase CT showing a filling defect within the left atrial appendage (Arrow). (D) 10 second delay phase demonstrating resolution of the filling defect within the left atrial appendage.

References: 

1. Klatt EC, Heitz DR, et al. Cardiac metastases.Cancer1990; 65:1456-1459
2. Pavitt, C& Lazoura, O, Lindsay A, et al. The Use of Cardiac CT for the Detection of Left Atrial Appendage Thrombus: A Quality Improvement Project. Heart 2014;100:A86-A87.
3. Hur J, Kim YJ, Lee HJ, et al. Left Atrial Appendage Thrombi in Stroke Patients: Detection with Two-Phase Cardiac CT Angiography versus Transesophageal Echocardiography. Radiology 2009 251:3, 683-690.
4. Burke A, Jeudy J, Virmani R. Cardiac tumours: an update. Heart 2008;94:117-123.
5. Stoddard MF, Dawkins PR, Prince CR, Ammash NM. Left atrial appendage thrombus is not uncommon in patients with acute atrial fibrillation and a recent embolic event: a transoesophageal echocardiographic study. J Am Coll Cardiol 1995;25(2):452-9.
6. Goldman ME, Pearce LA, Hart RG. Pathophysiologic correlates of thromboembolism in nonvalvular atrial fibrillation: reduced flow velocity in the left atrial appendage. J Am Soc Echocardiogr. 1999;12(12):1080-7.
7. Malik, S. Chen, N. et al. Transthoracic echocardiography: Pitfalls and Limitations as Delineated at Cardiac CT and MR imaging. Radiographics 2017; 37:383-406

A Complicated Infarct

I Harries¹, B Berlot¹, R Ascione², M Hamilton³, C Bucciarelli-Ducci¹

1. Department of Cardiology, Bristol Heart Institute, United Kingdom

2. Department of Cardiothoracic Surgery, Bristol Heart Institute, United Kingdom

3. Department of Radiology, Bristol Royal Infirmary, United Kingdom

A 53 year old male ex-smoker with no other cardiovascular risk factors presented to a local hospital with progressive dyspnoea following an episode of chest pain that had occurred six weeks prior. ECG showed sinus rhythm with anterior Q waves. Coronary angiography demonstrated a proximal occlusion of the left anterior descending (LAD) artery and mild non-flow limiting disease in the right and left circumflex coronary arteries. The patient was commenced on appropriate medical therapy and transferred to our institution for cardiac magnetic resonance (CMR) imaging to evaluate LAD territory viability.

Figure 1. Mid ventricular short and 2 chamber long axis PSIR late Gadolinium enhancement sequences of the left ventricle.

1. Is the LAD territory viable?
   1. No
   2. Yes

Answer:

1. No. The LAD territory is not viable. There is transmural late enhancement of the mid antero-septal, mid-anterior and mid anterolateral walls on the short axis view, and of the mid and apical anterior walls and apical cap on the long axis (2 chamber) view. The likelihood of functional recovery following revascularisation is very low in segments with >75% hyperenhancement ¹.

Figure 2. Mid ventricular short axis and long axis 2 chamber balanced SSFP cine stills of the left ventricle.

2. What complication of myocardial infarction is demonstrated?
   1. Left ventricular aneurysm
   2. Ventricular septal defect
   3. Papillary muscle rupture
   4. Left ventricular pseudoaneurysm
   5. Left ventricular thrombus

Answer:

d.         Left ventricular pseudoaneurysm.  Myocardial rupture is evidenced by the abrupt discontinuation of the myocardium in the mid anterior segment (white arrow) with containment by the overlying pericardium (red arrow).

Figure 3. Zoomed mid ventricular short axis balanced SSFP cine still of the left ventricle.

A pseudoaneurysm or ‘false aneurysm’ is formed when cardiac rupture is contained by adherent pericardium or scar tissue. Unlike true aneurysms, pseudoaneurysms contain no endocardium or myocardium and are significantly more likely to rupture than true aneurysms, which rarely rupture because of the densely fibrotic tissue found in the wall of true aneurysms ².

3. What is the appropriate management strategy?
   1. Surgical repair
   2. Medical therapy
   3. Revascularisation of the LAD (CABG or PCI)
   4. Cardiac transplant

Answer:

1. Surgical repair. If feasible, surgical repair is the preferred therapeutic option because conservative management of pseudoaneurysms carries a 30-45% risk of rupture and a mortality of almost 50%³. Perioperative mortality is less than 10% with greater risk for patients requiring concomitant mitral valve repair².

The patient successfully underwent left ventricular aneurysmectomy (Figure 4.), was established on appropriate medical therapy, had a primary prevention ICD implanted and is making a good recovery.

Figure 4. Mid ventricular short axis and long axis 2 chamber balanced SSFP cine stills of the left ventricle following left ventricular aneurysmectomy.

References

1. Kim RJ, Wu E, Rafael A, Chen EL, Parker MA, Simonetti O, Klocke FJ, Bonow RO, Judd RM. The use of contrast-enhanced magnetic resonance imaging to identify reversible myocardial dysfunction. N Engl J Med. 2000 Nov 16;343(20):1445-53.
2. Shapira O. (2017, Nov 27) Left ventricular aneurysm and pseudoaneurysm following acute myocardial infarction. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4900369/.
3. Frances C, Romero A, Grady D. Left ventricular pseudoaneurysm. J Am Coll Cardiol. 1998 Sep;32(3):557-61.

Dr Jamie Kitt, Dr Andrew Kelion  and Dr Elizabeth Orchard.

Department of Cardiology, Oxford Heart Centre, John Radcliffe Hospital, Oxford, United Kingdom

A 46-year-old civil servant was referred to us by a local district general hospital (DGH) in April 2018.  He had been admitted in October 2017 after developing rapid palpitations whilst in the shower. He attended his local Emergency Department and was found to be in atrial flutter with 2:1 block and a ventricular rate of 140 beats per minute. He was seen by the on-call cardiologist and started on Bisoprolol and Apixaban. He was referred to the local Electrophysiologist. An A&E bedside scan (GE V-scan) done locally was ‘reportedly normal’ and he went on to have a successful flutter (cavo-tricuspid isthmus) ablation in December 2017.

At our clinic in June 2018, he reported no further palpitations, but mentioned fatigue with reduced exercise tolerance compared to early 2017. On reflection, he felt that he had always struggled to keep up with his peers at school and university. He had no other past medical history of note, and was a non-smoker who drank only occasional alcohol. He took only Apixaban 5mg bd.

On examination, oxygen saturation was 99% on room air. Pulse rate was 66 and regular, with normal character and volume, and blood pressure was 115/60. Jugular venous pulse was normal. He had wide fixed splitting of the second heart sound, and a pan-systolic murmur loudest at the lower left sternal edge. The chest was clear.

12-lead electrocardiogram (ECG) demonstrated sinus rhythm, with partial right bundle branch block (RBBB) and a QRS duration of 100ms.

Question 1: What is the likely diagnosis at this point based on the current information?

1. Ventricular septal defect (VSD)
2. Atrio-ventricular septal defect (AVSD)
3. Mitral regurgitation
4. Atrial septal defect (ASD)
5. Pulmonary stenosis

Answer: 4. Atrial septal defect (ASD). The combination of long-standing exercise intolerance, an atrial arrhythmia, wide fixed splitting of the second heart sound and RBBB morphology on the ECG is highly suggestive of an ASD¹.

At follow up in the DGH, he had eventually had a formal trans-thoracic echo and a dilated right heart was noted as well as an atrial septal defect which prompted the referral to us. A transthoracic echocardiogram (TTE) at our clinic was reported as a primum ASD with a left to right shunt (Figure 1).  There was also moderate mitral regurgitation due to prolapse of the anterior mitral valve leaflet (AMVL) with thickening of the leaflet tips (Figure 2). The right ventricle (RV) was moderately dilated, with severe bi-atrial dilatation.

Figure 1. Trans-thoracic echo apical 4 chamber view A :  Severely enlarged left atrium  B: Severely dilated RA with evidence of RA pressure overload at end systole (arrow) C: RV dilatation (albeit in snap-shot at end-systole) D (arrow): Elongated AMVL with prolapse

Figure 2.  A: Zoomed apical 4 chamber of the inta-atrial septum showed a defect (measured as 1.3cm) reported as a primum ASD. B: Corresponding colour flow Doppler through the defect confirming left to right shunt

Transoesophageal echocardiography (TOE) was performed a few weeks later, and the images were reviewed at our Adult Congenital Heart Disease (ACHD) Multidisciplinary Team (MDT) Meeting. The study was felt to show a primum ASD, with an accompanying bubble study which appeared to show a left to right shunt (Figures 3A and 3B). However, the atrial defect itself was not clearly visualised, so cardiac magnetic resonance (CMR) imaging was advised to define the anatomy more precisely.

Figure 3A.  Trans-oesophageal echocardiohgram (TOE) mid-oesophageal at 71 degrees focusing on the intra-atrial septum (IAS) A: Severely enlarged right atrium. B: IAS with small primum ASD suspected but unable to clearly visualise at any angulation C: Off axis tri-leaflet aortic valve D: Partial view of a dilated RV

Figure 3B. Bubble study during TOE at 3^rd cardiac cycle after injection into left arm (unaware of left sided SVC at this time) consistent with large left to right shunt.

CMR was performed in July 2018, including a detailed atrial stack and a twist angiogram in addition to the standard set of sequences. The study reportedly showed a moderate secundum ASD located antero-inferiorly (Figure 4A and 4B), resulting in a 2:1 left to right shunt. A comment was made that no primum ASD was seen. There was a mildly dilated RV when indexed to his body surface area (235mls) with normal RV function, normal LV function, and mild mitral regurgitation. Normal pulmonary venous (PV) drainage was noted, but a persistent left-sided superior vena cava (SVC) was seen on the twist angiogram though it was unclear whether this was draining into the right atrium (RA).

Figure 4. Cardiac MRI performed using Siemens 1.5T magnet. 4A Atrial stack A:Severely dilated left atrium. B: Severely dilated right atrium. C (arrow): Atrial Septal defect visualised reported as moderate sized secundum atrial septal defect (ASD) measuring (21x17mm) which is located very antero-inferiorly. Flows subsequently  confirmed Qp:Qs 2:1. 4B Horizontal long axis (HLA) view also showing significant atrial septal defect (arrow) and D: moderately dilated RV

Question 2: What is the commonest variation in the thoracic venous system?

1. Anomalous drainage of right sided superior vena cava (SVC) to the left atrium (LA)
2. Persistent left-sided SVC (bilateral SVCs aka SVC duplication)
3. Isolated left sided SVC

Answer: 2. Persistent left-sided SVC, is the most common congenital venous anomaly in the chest.

It accounts for 10% of thoracic vein anomalies and is present in 0.3-0.5% of the general population². It is only seen in isolation in 10% of cases since in the vast majority of cases (82-90%) a normal (but small) right-sided SVC is also present, and a persistent bridging vein (left brachiocephalic vein) is seen in 25-35% of cases.

On further discussion at the ACHD MDT Meeting in August 2018, there was still no agreement on the exact anatomy despite TTE, TOE with a bubble study, and CMR. He was duly referred for a gated cardiac X-ray computed tomographic (CT) study, which resolved the confusion. CT demonstrated a right-sided SVC and inferior vena cava (IVC) draining normally into the RA. The persistent left-sided SVC (figure 5B in Powerpoint) drained into a completely de-roofed coronary sinus and LA (Figure 5), creating a large effective “ASD”. An additional small secundum ASD was also evident. PV drainage was normal. The right ventricle and both atria were dilated. The coronary arteries were normal.

Figure 5 . Gated Cardiac CT which was performed on a GE Revolution with 16cm detector, using Omnipaque 350 50ml at 5ml/s, saline 50ml at 5ml/s. No metoprolol or GTN was administered. Prospective gating at 70-80% as well as 0-100% at 20% current. 100kVp. Heart rate 64bpm. DLP 223mGy.cm.

5A: A: Deroofed coronary sinus creating large ‘ASD’ as well as a B: Secundum ASD and 5B shows C: Left sided SVC draining into De-roofed coronary sinus and Left atrium (LA).

Question 3: What is the commonest associated congenital lesion seen with a left sided SVC

1. Atrial septal defect (ASD)
2. Ventricular septal defect (VSD)
3. Coarctation of the aorta
4. Pulmonary stenosis
5. Anomalous pulmonary venous return

Answer: 1. ASD. Congenital heart defects are present in 4.4% of patients with left-sided SVC³. ASDs are the most common by far but it can also occur with a single atrium, VSDs, Tetralogy of Fallot, coarctation of the aorta, anomalous pulmonary venous drainage and pulmonary stenosis. These should be thus searched for if a left sided SVC is present. There are a number of possible drainage sites. Left-sided SVCs are often functionally insignificant with 92% draining into coronary sinus since venous return from the head, neck and upper limbs is delivered to the right atrium ³. In the other 8%, although drainage into the LA results in a right to left shunt, it is usually not large enough to cause cyanosis or symptoms ³but, in this case the coronary sinus ASD and second secundum ASD resulted in a large left to right shunt.

Discussion:

This case highlights the importance of comprehensive cardiological assessment of patients with new onset atrial arrhythmias, including a detailed TTE, particularly in young adults, before jumping to treat the rhythm disorder. It also highlights the importance of searching for other lesions once one congenital lesion has been identified. Moreover, it emphasises the strengths and limitations of the various imaging modalities used in assessment of complex congenital heart disease. Echocardiography and CMR provide excellent functional information. However, when the anatomy is uncertain, gated cardiac CT offers the unparalleled ability to perform extensive reorientation of a true three-dimensional dataset with high spatial resolution. There is no requirement for images to have been acquired in precisely the right plane, as for echo and CMR. Modern CT scanners such as the GE REVOLUTION also allow easy dose modulation across the entire cardiac cycle, so that even LV and RV systolic function can be calculated to complement the anatomical assessment.

References:

1. S Martin, E Shapiro and M Mukherjee. Atrial Septal Defects – Clinical Manifestations, Echo Assessment, and Intervention. Clin Med Insights Cardiol. 2014; 8 (Suppl 1): 93–98. PMCID: PMC4373719
2. Padhani AR, Hale HL. Mediastinal venous anomalies: potential pitfalls in cancer diagnosis. Br J Radiol. 1998; 71 (847): 792-8. Br J Radiol
3. Pretorius PM, Gleeson FV. Case 74: right-sided superior vena cava draining into left atrium in a patient with persistent left-sided superior vena