Clinical Radiology 70 (2015) 96e110
Contents lists available at ScienceDirect
Clinical Radiology journal homepage: www.clinicalradiologyonline.net
Pictorial Review
Pulmonary arteriovenous malformations and their mimics S.S. Gill a, M.E. Roddie a, C.L. Shovlin b, J.E. Jackson a, * a b
Department of Imaging, Imperial College Healthcare NHS Trust, London, UK NHLI Cardiovascular Sciences, Imperial College, London, UK
article in formation Article history: Received 28 June 2014 Received in revised form 24 August 2014 Accepted 1 September 2014
Pulmonary arteriovenous malformations (PAVMs) are abnormal communications between the pulmonary arteries and veins, which result in a right-to-left (ReL) shunt with resultant hypoxemia, the severity of which will depend upon the size and number of lesions. Most PAVMs occur in individuals with hereditary haemorrhagic telangiectasia (HHT) and are a cause of serious morbidity and mortality largely related to cerebrovascular complications secondary to paradoxical embolization. The importance of their recognition and treatment by embolization, even in the absence of symptoms, is well known. Their appearances on chest radiographs are often, but not always, characteristic and the CT appearances are diagnostic; however, there are a number of both vascular and non-vascular diseases that can cause confusion. This review serves to highlight these PAVM “mimics”. Ó 2014 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.
Introduction Pulmonary arteriovenous malformations (PAVMs) are abnormal dilated vessels that provide a right-to-left (ReL) shunt between the pulmonary artery and pulmonary vein, thereby bypassing the pulmonary capillary bed. They are more common than is generally recognized, affecting 1 in 2500 (95% CI, 1 in 1300 to 1 in 5600).1 Their diagnosis is important as they are associated with serious morbidity and mortality largely related to paradoxical embolization causing cerebrovascular complications, the risk of which can be significantly reduced by embolization.2e13 The vast majority of individuals with PAVMs have hereditary haemorrhagic telangiectasia (HHT), also known as OslereWebereRendu syndrome, which has a prevalence of 1 in 5000 to 8000.14,15 * Guarantor and correspondent: J.E. Jackson, Department of Imaging, Imperial College Healthcare NHS Trust, Hammersmith Hospital, Du Cane Road, London W12 0HS, UK. Tel.: þ44 020 8383 3485; fax: þ44 020 8383 3121. E-mail address: [email protected] (J.E. Jackson).
The diagnosis of PAVMs on the basis of clinical and radiological findings is generally straightforward; however, other diseases may, cause diagnostic confusion. This review describes firstly the characteristic imaging appearances of pulmonary AVMs and then presents a variety of PAVM mimics, all of which were initially misdiagnosed as PAVMs. These mimics can be conveniently separated into vascular and non-vascular abnormalities (Table 1).
Radiological features of PAVMs PAVMs are divided into simple and complex types16; the former is more common and consists of an aneurysmal venous sac supplied by a single artery and drained by one or more veins. Complex PAVMs consist of a collection of venous sacs supplied by multiple vessels arising from adjacent segmental or subsegmental pulmonary artery branches and draining into multiple veins. They are most commonly discrete lesions with only a few feeding vessels,
http://dx.doi.org/10.1016/j.crad.2014.09.003 0009-9260/Ó 2014 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.
S.S. Gill et al. / Clinical Radiology 70 (2015) 96e110
97
Table 1 Mimics of pulmonary arteriovenous malformations. Vascular Pulmonary aneurysmal disease
True aneurysms
False aneurysms
Pulmonary varices
Pulmonary artery collaterals
Idiopathic Secondary
Syphilis Connective tissue diseases Behc¸et’s Takayasu’s CTEPH and IPH
Tuberculosis Following pneumonia Septic emboli Connective tissue diseases
Congenital Acquired
Associated with mitral valve disease Secondary to chronic tuberculosis or sarcoidosis Associated with IPH and CTEPH
Non-vascular Bronchocoele Tumours
Congenital Acquired Primary carcinoid Metastases
Congenital bronchial atresia Foreign body; Endobronchial tumour; Bronchiectasis of any cause
CTEPH, chronic thromboembolic pulmonary hypertension; IPH, idiopathic pulmonary hypertension.
Figure 1 A 54-year-old man with HHT and right basal PAVM. (a) Frontal chest radiography shows typical plain radiographic appearances of a PAVM at the right lung base with a rounded soft-tissue opacity projected over the right hemidiaphragm with hypertrophied feeding and draining vessels. (b,c) Pulmonary arteriograms of the same patient demonstrate the hypertrophied feeding artery supplying a dilated venous sac from which there is a single dominant draining vein.
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S.S. Gill et al. / Clinical Radiology 70 (2015) 96e110
other more common diseases, including malignant neoplasms, are often considered before the diagnosis is made (Fig 2a). Complex PAVMs are generally less well defined, although rounded nodular elements associated with prominent feeding arteries and draining veins are usually evident (Fig 3a). Diffuse lesions involving whole lung segments are seen as an area of generalized increased opacity with marked prominence of vascular markings but no discrete nodules (Fig 4a).
CT
Figure 2 A pulmonary nodule demonstrated at chest radiography performed to investigate a cough in a 51-year-old man with no clinical or family history of HHT. (a) Frontal chest radiography demonstrates a well-defined oval soft-tissue opacity projected over the right mid zone. There is possibly some prominence of vascular markings medial to this abnormality but no clearly identifiable feeding and draining vessels. The patient was referred for CT to exclude a neoplasm. (b) Thin-slab maximum intensity projection (MIP) axial CT image on a lung window setting demonstrates the typical features of a PAVM of simple type with hypertrophied feeding and draining vessels communicating with a dilated venous sac.
but may be diffuse and involve whole lung segments and, rarely, an entire lobe.
Chest radiography The classical appearance of a PAVM on a plain chest radiograph consists of a well-defined, rounded, soft-tissue nodule of any size, but most frequently 1e2 cm in diameter, associated with enlarged feeding and draining vessels (Fig 1a). Peripheral curvilinear calcification is described but is rare. PAVMs are commonly multiple and are typically most numerous at the lung bases. When these classical appearances are seen, particularly in an individual undergoing screening investigations for HHT, a diagnosis of PAVMs can be made with some confidence. In many instances, however, the plain film appearances are more subtle and/or feeding and draining vessels less obvious, and
CT is generally considered the reference standard investigation for diagnosing PAVMs and demonstrating their size and extent prior to therapy. The imaging features are characteristic on lung windows. The classical appearances of simple PAVMs are those of a well-defined peripheral nodule, which may be rounded or multilobulated, into which one feeding artery, and from which one or more draining veins, can be clearly visualized (Fig 2b). The draining veins are typically 1e2 mm larger than the feeding arteries. In the vast majority of cases, the diagnosis is simple. Tiny malformations with venous sacs measuring
Contents lists available at ScienceDirect
Clinical Radiology journal homepage: www.clinicalradiologyonline.net
Pictorial Review
Pulmonary arteriovenous malformations and their mimics S.S. Gill a, M.E. Roddie a, C.L. Shovlin b, J.E. Jackson a, * a b
Department of Imaging, Imperial College Healthcare NHS Trust, London, UK NHLI Cardiovascular Sciences, Imperial College, London, UK
article in formation Article history: Received 28 June 2014 Received in revised form 24 August 2014 Accepted 1 September 2014
Pulmonary arteriovenous malformations (PAVMs) are abnormal communications between the pulmonary arteries and veins, which result in a right-to-left (ReL) shunt with resultant hypoxemia, the severity of which will depend upon the size and number of lesions. Most PAVMs occur in individuals with hereditary haemorrhagic telangiectasia (HHT) and are a cause of serious morbidity and mortality largely related to cerebrovascular complications secondary to paradoxical embolization. The importance of their recognition and treatment by embolization, even in the absence of symptoms, is well known. Their appearances on chest radiographs are often, but not always, characteristic and the CT appearances are diagnostic; however, there are a number of both vascular and non-vascular diseases that can cause confusion. This review serves to highlight these PAVM “mimics”. Ó 2014 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.
Introduction Pulmonary arteriovenous malformations (PAVMs) are abnormal dilated vessels that provide a right-to-left (ReL) shunt between the pulmonary artery and pulmonary vein, thereby bypassing the pulmonary capillary bed. They are more common than is generally recognized, affecting 1 in 2500 (95% CI, 1 in 1300 to 1 in 5600).1 Their diagnosis is important as they are associated with serious morbidity and mortality largely related to paradoxical embolization causing cerebrovascular complications, the risk of which can be significantly reduced by embolization.2e13 The vast majority of individuals with PAVMs have hereditary haemorrhagic telangiectasia (HHT), also known as OslereWebereRendu syndrome, which has a prevalence of 1 in 5000 to 8000.14,15 * Guarantor and correspondent: J.E. Jackson, Department of Imaging, Imperial College Healthcare NHS Trust, Hammersmith Hospital, Du Cane Road, London W12 0HS, UK. Tel.: þ44 020 8383 3485; fax: þ44 020 8383 3121. E-mail address: [email protected] (J.E. Jackson).
The diagnosis of PAVMs on the basis of clinical and radiological findings is generally straightforward; however, other diseases may, cause diagnostic confusion. This review describes firstly the characteristic imaging appearances of pulmonary AVMs and then presents a variety of PAVM mimics, all of which were initially misdiagnosed as PAVMs. These mimics can be conveniently separated into vascular and non-vascular abnormalities (Table 1).
Radiological features of PAVMs PAVMs are divided into simple and complex types16; the former is more common and consists of an aneurysmal venous sac supplied by a single artery and drained by one or more veins. Complex PAVMs consist of a collection of venous sacs supplied by multiple vessels arising from adjacent segmental or subsegmental pulmonary artery branches and draining into multiple veins. They are most commonly discrete lesions with only a few feeding vessels,
http://dx.doi.org/10.1016/j.crad.2014.09.003 0009-9260/Ó 2014 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.
S.S. Gill et al. / Clinical Radiology 70 (2015) 96e110
97
Table 1 Mimics of pulmonary arteriovenous malformations. Vascular Pulmonary aneurysmal disease
True aneurysms
False aneurysms
Pulmonary varices
Pulmonary artery collaterals
Idiopathic Secondary
Syphilis Connective tissue diseases Behc¸et’s Takayasu’s CTEPH and IPH
Tuberculosis Following pneumonia Septic emboli Connective tissue diseases
Congenital Acquired
Associated with mitral valve disease Secondary to chronic tuberculosis or sarcoidosis Associated with IPH and CTEPH
Non-vascular Bronchocoele Tumours
Congenital Acquired Primary carcinoid Metastases
Congenital bronchial atresia Foreign body; Endobronchial tumour; Bronchiectasis of any cause
CTEPH, chronic thromboembolic pulmonary hypertension; IPH, idiopathic pulmonary hypertension.
Figure 1 A 54-year-old man with HHT and right basal PAVM. (a) Frontal chest radiography shows typical plain radiographic appearances of a PAVM at the right lung base with a rounded soft-tissue opacity projected over the right hemidiaphragm with hypertrophied feeding and draining vessels. (b,c) Pulmonary arteriograms of the same patient demonstrate the hypertrophied feeding artery supplying a dilated venous sac from which there is a single dominant draining vein.
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S.S. Gill et al. / Clinical Radiology 70 (2015) 96e110
other more common diseases, including malignant neoplasms, are often considered before the diagnosis is made (Fig 2a). Complex PAVMs are generally less well defined, although rounded nodular elements associated with prominent feeding arteries and draining veins are usually evident (Fig 3a). Diffuse lesions involving whole lung segments are seen as an area of generalized increased opacity with marked prominence of vascular markings but no discrete nodules (Fig 4a).
CT
Figure 2 A pulmonary nodule demonstrated at chest radiography performed to investigate a cough in a 51-year-old man with no clinical or family history of HHT. (a) Frontal chest radiography demonstrates a well-defined oval soft-tissue opacity projected over the right mid zone. There is possibly some prominence of vascular markings medial to this abnormality but no clearly identifiable feeding and draining vessels. The patient was referred for CT to exclude a neoplasm. (b) Thin-slab maximum intensity projection (MIP) axial CT image on a lung window setting demonstrates the typical features of a PAVM of simple type with hypertrophied feeding and draining vessels communicating with a dilated venous sac.
but may be diffuse and involve whole lung segments and, rarely, an entire lobe.
Chest radiography The classical appearance of a PAVM on a plain chest radiograph consists of a well-defined, rounded, soft-tissue nodule of any size, but most frequently 1e2 cm in diameter, associated with enlarged feeding and draining vessels (Fig 1a). Peripheral curvilinear calcification is described but is rare. PAVMs are commonly multiple and are typically most numerous at the lung bases. When these classical appearances are seen, particularly in an individual undergoing screening investigations for HHT, a diagnosis of PAVMs can be made with some confidence. In many instances, however, the plain film appearances are more subtle and/or feeding and draining vessels less obvious, and
CT is generally considered the reference standard investigation for diagnosing PAVMs and demonstrating their size and extent prior to therapy. The imaging features are characteristic on lung windows. The classical appearances of simple PAVMs are those of a well-defined peripheral nodule, which may be rounded or multilobulated, into which one feeding artery, and from which one or more draining veins, can be clearly visualized (Fig 2b). The draining veins are typically 1e2 mm larger than the feeding arteries. In the vast majority of cases, the diagnosis is simple. Tiny malformations with venous sacs measuring
