Management of pulmonary hypertension: Radiologist's role

Transcription

1 Management of pulmonary hypertension: Radiologist's role Poster No.: C-2615 Congress: ECR 2015 Type: Educational Exhibit Authors: S. Hantous-Zannad, L. Dridi, M. Attia, H. Neji, A. Zidi, I Baccouche, K. Ben Miled ; Ariana/TN, Tunis/TN Keywords: Embolism / Thrombosis, Haemodynamics / Flow dynamics, Hypertension, Screening, Education, CT-High Resolution, CTAngiography, CT, Thorax, Pulmonary vessels, Lung DOI: /ecr2015/C-2615 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 36

2 Learning objectives 1. To depict usefulness of Multidetector CT pulmonary angiography (MDCT PA) in the managing algorithm of Pulmonary Hypertension (PH) both for screening and diagnostic. 2. To assess right circulation overload signs 3. To determine MDCT findings allowing a physiopathological approach to PH and helping aetiologic investigation. Page 2 of 36

3 Background I. INTRODUCTION Pulmonary hypertension is a progressive disease of the pulmonary arteries characterized by abnormally elevated pressure in the pulmonary circulation, as a result of extensive vascular proliferation and remodeling. The normal adult pulmonary vascular bed is a low-pressure, low-resistance, highly distensible system, and is capable of accommodating large increases in blood flow with minimal elevations of pulmonary artery pressure (PAP). In patients with suspected PH, the diagnostic approach includes four stages: suspicion, detection, classification and functional evaluation. Many conditions that cause pulmonary hypertension have suggestive findings at multidetector computed tomography (MDCT). Without treatment, pulmonary hypertension progresses rapidly to right ventricular failure and death, typically within 3 years of the diagnosis. Some causes may be surgically treatable, (thromboendarterectomy) whereas others may demonstrate adverse reactions to vasodilator therapies used during the course of treatment. Therefore, the radiologist plays an important role in evaluating patients with this disease. II.DEFINITION Pulmonary hypertension is hemodynamically defined as an abnormal elevation of mean pulmonary artery pressure (PAP) associated with an increased pulmonary vascular resistance, regardless of the underlying mechanism. PAP> 25 mm Hg at rest PAP> 30 mm Hg during exercise Pulmonary arterial hypertension is restricted for conditions with a hemodynamic profile in which high pulmonary pressure is a result of elevated precapillary pulmonary resistance and normal pulmonary venous pressure; groups 3, 4, and 5 in the Dana Point classification system (Table 1) share this hemodynamic profile. The aim of the Dana Point classification system is to group together different manifestations of the disease that share similar pathophysiologic traits. III.PATHOLOGY There are two possible pathophysiologic explanations: Page 3 of 36

4 1/increased pulmonary venous resistance as in lung diseases. 2/increased pulmonary venous flow, such as with a left-to-right shunt. This results in an arteriopathy which, when reaching the stage of fibrosis of the wall, becomes irreversible. The chronically elevated pulmonary arterial pressure and vascular resistance lead to right ventricular dilatation and hypertrophy then right atrial enlargement, as compensatory mechanisms that allow the right ventricle to produce a larger stroke volume and maintain cardiac output. IV. CLINICAL PRESENTATION Symptoms of PH are nonspecific. The clinical course of pulmonary hypertension is divided into three phases: 1/asymptomatic compensated 2/symptomatic decompensating (fatigue, breathlessness on exertion) 3/advanced decompensated (right ventricular faiure with peripheral oedema and ascites) V. DIAGNOSIS AND ASSESSMENT OF PULMONARY HYPERTENSION 1. Suspicion PH usually manifests insidiously with exertional dyspnea and fatigue. It is important to be cautious with young patients who present with exertional dyspnea and conditions such as connective tissue disorders, prior pulmonary emboli, and congenital heart disease, at risk for PH. 2.Detection Detection uses combination of ECG, chest radiography and transthoracic Doppler echocardiography, which measures systolic pulmonary arterial pressure and tricuspid regurgitant jet velocity with sensitivity of 79%-100% and specificity of 68%-98%. 3.Classification PH is systematically classified based on the Dana Point classification system (Table 1) in order to determine its cause, to rule out the more common clinical groups of PH (leftsided heart disease, lung disease) and more specifically those for which a cure exists such as chronic thromboembolic pulmonary hypertension. Page 4 of 36

5 For this purpose, MDCT may be used to assess both cardiac and extracardiac causes of pulmonary hypertension such as chronic thromboembolic pulmonary hypertension, longstanding left-to-right shunts and mediastinal disorders. High-resolution images of the lung parenchyma provide information about parenchymal diseases of the lung and alterations of lung parenchyma resulting from PH. 4. Functional Evaluation Disease severity must be assessed with cardiac magnetic resonance (CMR) of the right side of the heart or catherization in order to determine the prognosis and optimize treatment. VI. IMAGING ALGORYTHM IN PATIENTS WITH SUSPECTED PULMONARY HYPERTENSION Different imaging modalities are used to diagnose and classify pulmonary hypertension. Multidetector CT with pulmonary angiography (MDCTPA) has a central role as shown in Fig 1. Page 5 of 36

6 Images for this section: Table 1: Dana Point Classification of Pulmonary Hypertension Grosse C, Grosse A. CT findings in deseases associated with pulmonary hypertension : a current review. RadioGraphics 2010 ;30 : Page 6 of 36

7 Fig. 1: Imaging Algorythm in Patients with suspected PH. CTEPH = chronic thromboembolic pulmonary hypertension, MDCTPA = multidetector CTPA, PA = pulmonary artery, PE = pulmonary emboli, PCH = pulmonary capillary hemangiomatosis, PVOD = pulmonary veno-occlusive disease, RV = right ventricle, V/Q = ventilationperfusion. Penna E, Dennie C, Veinot J et al. Pulmonary hypertension, how the radiologist can help? RadioGraphics 2012;32:9-32. Page 7 of 36

8 Findings and procedure details We made a retrospective review of MDCT PA performed between march 2013 and august 2014 in our tertiary-referral teaching hospital specialized in chest diseases, in patients either presenting with unexplained PH diagnosed through echocardiography or complaining from parenchymal lung disease or possible pulmonary vascular disease resulting in PH. I. CHEST RADIOGRAPHY Chest radiography is still the initial imaging study performed. The classic radiographic findings of pulmonary hypertension may be seen in the late stages of the disease (Fig. 2): Central pulmonary arterial dilatation; Increased diameter (15 mm in women and 16 mm in men) of the right interlobar artery, measured from its lateral aspect to the interlobar bronchus; Right atrium and right ventricle enlargement in more advanced cases It might show signs indicative of its underlying cause, such as interstitial lung disease, emphysema, chest wall deformities or left-sided heart disease. II. MULTIDETECTOR CTPA MDCT PA allowed screening for PH but also, showed signs of specific aetiologies. Pulmonary Hypertension non-specific MDCT PA signs can be divided into three categories: A/ General PH signs 1. Vascular signs: 1/Enlarged pulmonary trunk On transverse images, the main pulmonary artery is evaluated at the level of its bifurcation, orthogonal to its long axis: > 29 mm diameter Larger than the adjacent ascending aorta (Fig.3) Page 8 of 36

9 However, this sign is poorly specific in case of underlying interstitial lung disease 2/Enlarged pulmonary arteries A segmental artery-to-bronchus diameter ratio of 1:1 or more in three or four lobes has a specificity of 100% for the presence of pulmonary hypertension (Fig.4). 3/Wall-adherent apposition thrombi in central pulmonary arteries (Fig.5) 2. Cardiac signs: Findings of adaptation and failure of the right side of the heart: Right ventricular hypertrophy (wall thickness >3 mm) (Fig.6); Straightening or leftward bowing of the interventricular septum; Right ventricular dilatation (right-to-left ventricle diameter ratio > 1:1 at the midventricular level on axial images) (Fig.7); Decreased right ventricular ejection fraction; Dilatation of the inferior vena cava and hepatic veins; Pericardial effusion. 3. Parenchymal signs: Mozaic pattern of attenuation, with no systematization, due to perfusion abnormalities (Fig.8); Centrilobular ground-glass nodules (Fig.9); Seen in patients with idiopathic PAH or with pulmonary capillary hemangiomatosis B/Signs specific to certain PH aetiologies Signs of specific aetiologies were thoroughly searched for. In our hospital, the most frequently incriminated pathology is pulmonary disease (chronic obstructive bronchopathy, pulmonary fibrosis and tuberculosis sequelae) followed by thromboembolic pulmonary hypertension, pulmonary arterial hypertension and left heart diseases, other causes being seldom but worth identifying (Behçet's disease, Rhumathoid arthritis, sarcoidosis, histiocytosis and Takayashu disease) We distinguish using Dana classification: Page 9 of 36

10 1. Group 1: Pulmonary arterial hypertension (PAH) 1.1. Idiopathic PAH: Seen usually in young adults (20-45 years old), more frequently women. Evocative CT signs: Central pulmonary artery dilatation Absence of detectable intraluminal thrombi Abrupt decrease in the caliber of segmental and subsegmental arteries Wall-adherent apposition thrombi in the central pulmonary arteries in severe cases (Fig.5) 1.2. Heritable PAH a.bone morphogenetic protein receptor type 2 b.activin receptor-like kinase type 1 There are no specific CT signs Drug and Toxin induced 1.4.Associated with HIV, with portal hypertension, with schizostomiasis, with chronic hemolytic anemia, with congenital heart diseases: In these last cases, there are no particular chest CT signs. Though, a particular pathology deserves mentioning: Eisenmenger syndrome: It is a complication of an uncorrected high-flow, high-pressure congenital heart anomaly leading to chronic pulmonary arterial hypertension and shunt reversal. The most incriminated lesions are (vascular septal defect, atrioventricular septal defect, ductus arteriosus, abnormal pulmonary venous return) MDCT PA might show the intra cardiac defect (Fig.10), the abnormal pulmonary venous return (Fig.11). 1'. Group 1#: Veno-occlusive Disease and Pulmonary Capillary Hemangiomatosis Page 10 of 36

11 These are rare and particular causes of pulmonary arterial hypertension, commonly seen in children and young adults. Due to obliteration of the postcapillary veins. Evocative CT signs: Poorly defined centrilobular ground-glass nodules (Fig.9), Thickened interlobular septa and bronchial walls (Fig.12), Pleural effusions (Fig.12), Enlarged mediastinal lymph nodes. 2. Group 2: Left-sided Heart Disease One of the most common causes of pulmonary hypertension although not frequent in our rd 3 line center (left ventricular systolic or diastolic dysfunction and valvular disorders) Backward transmission of elevated left atrial pressure into the pulmonary venous circulation explains this condition. The etiological diagnosis is usually made through echocardiography and MDCT PA has no evident role although it might show signs of pulmonary edema due to left ventricular failure. 3. Group 3: Lung Disease Lung disease is the most common PH cause in our hospital. MDCT PA shows mostly specific or evocative signs of the causal lung disease. It is mostly represented by: Idiopathic interstitial lung disease (Fig.13) Interstitial lung disease secondary to sarcoidosis (Fig.14), vasculatis (Fig.15), or connective tissue disease (Fig.16) Tuberculosis sequelae (Fig.17) Chronic obstructive pulmonary disease Sleep disordered breathing Page 11 of 36

12 It must be kept in mind that in patients with pulmonary fibrosis, pulmonary artery dilatation may occur in the absence of pulmonary arterial hypertension; thus, the main pulmonary artery diameter at CT is an unreliable indicator of pulmonary hypertension in this patient group. The ratio of the pulmonary artery diameter to the ascending aorta diameter is more reliable. 4. Group 4: Chronic Thromboembolic Disease Chronic thromboembolic disease is a cause of pulmonary hypertension that must be recognized as it may be successfully treated with pulmonary thromboendarterectomy. Evocative CT signs 1/Vascular Signs: Enlarged pulmonary trunk Complete obstruction, indicated by thin occluded vessels (Fig.18) Marginal, partial filling defects (Fig.19) Inequality of vessel diameter Presence of webs or bands (Fig.20) Collateral systemic supply 2/ Parenchymal Signs: Systematized mosaic pattern of perfusion (Fig.21) Cylindrical bronchial airway pseudo dilation (Fig.22) Scars from prior pulmonary infarction 5. Group 5: Unclear multifactorial mechanisms 5.1. Haematological disorders: myeloproliferative disorders, splenectomy 5.2. Systemic vasculitis : disorders: pulmonary histiocytosis, lymphangioleiomyomatosis, v Histiocytosis X Page 12 of 36

13 Pulmonary histiocytosis X is an uncommon but important cause of pulmonary fibrosis and honeycombing in young adults. CT findings: Predominantly upper lobe nodules and cysts are quite specific of this disorder. As pulmonary histiocytosis X progresses, the nodules decrease in number, leaving multiple thin-walled cysts. (Fig. 23) v Lymphangiomyomatosis Lymphangioleiomyomatosis (LAM) is an uncommon interstitial lung disease that exclusively affects women, usually during their reproductive years. It is characterized pathologically by abnormal proliferation of LAM cells in the lungs and in thoracic and retroperitoneal lymphatics. CT findings: Thin walled cysts of variable sizes surrounded by normal lung parenchyma Interlobular septal thickening Dilated thoracic duct Alveolar haemorrhages v Behçet's Disease It is a rare immune-mediated small-vessel systemic vasculitis, more frequent in young men. CT findings: Usually coexistant acute and chronic pulmonary embolism signs. Pulmonary arteries aneurysms (Fig.24) 5.3. Metabolic disorders: glycogen storage disease, Gaucher disease, thyroid disorders, with no specific CT signs Other: chronic renal failure, fibrosing mediatinitis... Page 13 of 36

14 Images for this section: Fig. 2: Right interlobar artery dilatation associated with right atrium and right ventricle dilation. Radiology and Medical Imaging, Abderrahmen Mami Hospital- Ariana/TN Page 14 of 36

15 Fig. 3: Axial MDCT PA showing dilatation (29 mm or more) of the main pulmonary artery. The ratio of the main pulmonary arterial diameter to that of the ascending aorta is also greater than 1. Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Page 15 of 36

16 Fig. 4: Axial lung reconstruction showing segmental artery-to-bronchus diameter ratio of more than 1:1. Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Page 16 of 36

17 Fig. 5: MDCT axial image showing a wall-adherent apposition thrombi in central pulmonary arteries Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana/TN Page 17 of 36

18 Fig. 6: Oblique MPR reconstruction in the cardiac short axis plane showing hypertrophy of the right ventricle wall. Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Page 18 of 36

19 Fig. 7: MPR Oblique reconstruction in the cardiac 4 chamber plane, showing great dilatation of the right ventricle with straightening of the interventricular septum. Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Page 19 of 36

20 Fig. 8: Minip axial lung reconstruction showing not systematized mosaic attenuation perfusion pattern. Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Page 20 of 36

21 Fig. 9: MIP axial lung reconstruction showing centrilobular ground-glass nodules. Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Page 21 of 36

22 Fig. 10: Axial MDCT PA image showing the interventricular septal defect (blue arrow) and the right ventricle wall hypertrophy (white arrow) Radiology and Medical Imaging, Abderrahmen Mami Hospital of Tunis - Ariana/TN Page 22 of 36

23 Fig. 11: Axial MDCT PA image showing abnormal right superior pulmonary vein return in the superior vena cava. Radiology and Medical Imaging, Abderrahmen Mami Hospital of Tunis - Ariana/TN Page 23 of 36

24 Fig. 12: Axial Lung reconstruction showing thickened interlobular septa and pleural effusions Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Page 24 of 36

25 Fig. 13: Usual Interstitial Pneumonia: Axial CT lung reconstruction showing an heterogeneous appearance of the lung parenchyma, with reticular opacities, subpleural honeycombing (blue arrows), traction bronchiectasis (white arrow), and focal areas of ground-glass opacity (red arrow) Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Page 25 of 36

26 Fig. 14: Axial CT lung reconstruction (a) and coronal reconstruction (b) showing perilymphatic micronodular pattern easily seen in the subpleural area (blue circle) associated with mediastinal non compressive lymphadenopathy (blue arrow): Sarcoïdosis. Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Fig. 15: Axial MDCT PA image (a) and oblique reconstruction showing Aortic and pulmonary trunk wall thinckening (a) associated with a diffuse regular wall thickening of an inferior lobar artery (b): Takayashu arteritis. radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Page 26 of 36

27 Fig. 16: Axial (a) and coronal (b) CT lung reconstructions showing bronchiectasis and honeycombing lesions (blue circle) predominantly in lower lobes associated with multiple scattered areas of air trapping consistent with bronchiolitis obliterans (white circle): Rhumathoid arthritis. Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Fig. 17: Tuberculosis Sequelae: a/axial CT plane showing an enlarged pulmonary trunk, calcified lymph nodes (blue arrow) and pleural thickening (white arrow). b/same patient, the coronal lung reconstruction shows a left apical cavity Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Page 27 of 36

28 Fig. 18: Sagittal MIP reconstruction showing complete obstruction of a segmental artery appearing as a thin occluded vessel Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Page 28 of 36

29 Fig. 19: Axial MDCT image showing a marginal, partial filling defect Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Page 29 of 36

30 Fig. 20: Axial MDCT image showing the presence of webs as an intraluminal band Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Page 30 of 36

31 Fig. 21: Axial lung reconstruction showing systematized mosaic patterns of perfusion Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Page 31 of 36

32 Fig. 22: Coronal Minip reconstruction showing cylindrical bronchial airway pseudo dilation Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Page 32 of 36

33 Fig. 23: Axial lung reconstruction showing predominantly upper lobes lesions with a few nodules (blue circle) and mostly multiple thin-walled cysts (blue arrow): Histiocytosis X. Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Page 33 of 36

34 Fig. 24: Coronal MDCT reconstruction showing a partially thrombosed aneurysm of the apico-dorsal artery: Behçet's disease. Radiology and Medical Imaging, Abderrahmen Mami Hospital - Ariana /TN Page 34 of 36

35 Conclusion Radiologists must be aware of their central role in the management of PH. MDCT is useful for the screening, detection and classification of PH but also for the assessment of its impact on the RV function and the investigation of underlying disorders especially those with possible treatment. Page 35 of 36

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