Computed tomography appearances of the lung parenchyma in pulmonary hypertension

Computed tomography (CT) is a valuable tool in the workup of patients under investigation for pulmonary hypertension (PH) and may be the first test to suggest the diagnosis. CT parenchymal lung changes can help to differentiate the aetiology of PH. CT can demonstrate interstitial lung disease, emphysema associated with chronic obstructive pulmonary disease, features of left heart failure (including interstitial oedema), and changes secondary to miscellaneous conditions such as sarcoidosis. CT also demonstrates parenchymal changes secondary to chronic thromboembolic disease and venous diseases such as pulmonary venous occlusive disease (PVOD) and pulmonary capillary haemangiomatosis (PCH). It is important for the radiologist to be aware of the various manifestations of PH in the lung, to help facilitate an accurate and timely diagnosis. This pictorial review illustrates the parenchymal lung changes that can be seen in the various conditions causing PH.     

Pulmonary hypertension: the contribution of MDCT to the diagnosis of its different types

Pulmonary hypertension is characterized by progressive involvement of the pulmonary vessels that leads to increased vascular resistance and consequently to right ventricular failure. Vascular lesions are a common factor in a wide spectrum of diseases, and their result, pulmonary hypertension, is a severe clinical condition with a poor prognosis that worsens the normal course of the diseases to which it is associated (COPD, collagen disease, sarcoidosis, and congenital or acquired heart disease). It is important for pulmonary hypertension to be diagnosed as early as possible because nowadays drugs can reduce mortality and improve the quality of life; furthermore, some types of pulmonary hypertension (e.g., chronic thromboembolism and those associated with some congenital heart diseases like left-to-right shunt) can be treated surgically. In cases of suspected pulmonary hypertension, imaging methods can confirm the diagnosis, suggest a cause, help choose the most appropriate treatment, and monitor the response to treatment. This review describes the approach to pulmonary hypertension using different imaging techniques; special emphasis is given to the role of multidetector CT (MDCT), which makes it possible to study all the organs in the thorax in a single acquisition. We review the radiological signs of pulmonary hypertension and the current (Dana Point) radiological criteria for classifying the type of hypertension based on alterations in the lung parenchyma, mediastinum, pleural spaces, and pericardium, as well as on the study of the chambers of the heart.     

Classification and diagnosis of pulmonary hypertension

An increase in wedge pressure distinguishes right heart strain due to pulmonary congestion from cor pulmonale with normal pulmonary capillary pressure. Pulmonary hypertension might be due to exogenous hypoxia, obstructive sleep apnea, acute and chronic airway obstruction, diseases of the lung parenchyma, and vascular bed impairment of the thoracopulmonary mechanics, including neurogenic and muscular disorders, cardiac insufficiency of the left heart, and valvular diseases.     

慢性心力衰竭的CT表现

目的:探讨慢性心力衰竭的CT表现。材料和方法:回顾性分析28例慢性心力衰竭的CT表现。结果:左心室增大16例、右心室增大8例、左心房增大6例、右心房增大4例,左、右心房增大3例,肺水肿24例、胸腔积液25例、肺动脉扩张3例、升主动脉扩张5例和冠状动脉钙化7例。左心衰CT示肺水肿、左心室扩大和胸腔积液。右心衰CT示右心室扩大、主肺动脉扩张和胸腔积液。全心衰竭CT示左右心室扩大,肺水肿和双侧胸腔积液。结论:CT可显示心脏各房室扩大、大动脉扩张、肺水肿、胸腔和心包积液以及冠状动脉钙化,为诊断原发心脏疾病及慢性心力衰竭提供重要依据。     

CT evaluation of chronic thromboembolic pulmonary hypertension.

Eight patients with chronic thromboembolic pulmonary hypertension (CTPH) that had been demonstrated by perfusion lung scan, pulmonary arteriography, and right heart catheterization had their pulmonary circulation evaluated by CT. Eight subjects without lung pathology were also studied for comparison. High resolution CT from apex to base with 1 cm thick sections after intravenous injection of contrast medium was performed in each individual. Emboli lodged in main pulmonary arteries on arteriography were regularly shown by CT, whereas those in segmental or smaller arteries were not detected. Diameters of the main pulmonary arteries measured on CT correlated with systolic pulmonary artery pressure (p < 0.001). The ratio between diameters of segmental arteries and the corresponding bronchi (A/B ratio) on CT was > 1 in 72 of 144 examined pulmonary segments (18 segments for each patient) in patients with CTPH. The ratio was > 1 in only 10 of 144 examined segments in normal control subjects. Dilatation of bronchial arteries was present in four of eight patients with CTPH. The parenchymal density in patients with CTPH was significantly higher in the axial than in the middle or peripheral lung compartments. In conclusion, CT may help with the diagnosis of CTPH by detecting thrombi of main arteries and by showing characteristic findings; moreover, it is accurate in estimating pulmonary arterial pressure secondary to thromboembolic obstruction.     

Pulmonary artery sarcoma mimicking chronic thromboembolic disease: Computed tomography and magnetic resonance imaging findings

Purpose The diagnosis of the rare primary malignant tumors of the pulmonary arteries is often delayed as symptoms are nonspecific.Methods Computed tomography (CT) and magnetic resonance imaging (MRI) of three patients with occlusion of the right pulmonary artery, two with sarcoma and one with chronic thromboembolic disease were analyzed for discriminating diagnostic criteria.Results Criteria suggesting pulmonary artery sarcoma are inhomogeneous high or low attenuation (hemorrhage, necrosis), soft-tissue density in pulmonary arteries, vascular distension, enhancement after administration of gadopentetate dimeglumine. Criteria for chronic thromboembolic disease are homogeneous soft-tissue lesions, abrupt vascular narrowings and cutoffs, as well as regional parenchymal hyperdensities.Conclusion CT and MRI provide complementary findings suggesting advanced pulmonary artery sarcoma instead of chronic thromboembolism.     

Pulmonary artery hypertension in chronic obstructive lung disease. The place of morphometric studies in thoracic radiography

Standard biplane chest X-rays were tested for the validity of morphometric criteria in the diagnosis of pulmonary artery hypertension. Twenty-seven patients suffering from chronic obstructive lung disease were examined and compared with a control group without cardiopulmonary disease. The diameter of the right and left pulmonary artery, pulmonary conus and the hilar-to-thoracic ratio were significantly increased in patients with chronic obstructive lung disease (p less than 0,0001). Measurement of the right pulmonary artery was 19.7 +/- 3.9 mm compared to 13.6 +/- 1.2 mm of the control group; mean hilar thoracic index was 0.35 compared to 0.31. Thus if the width of the descending branch of the right pulmonary artery was above 16 mm, pulmonary arterial hypertension was suggested, with a specificity of almost 100%, although the sensitivity of the diagnosis was only 59%. The mean pulmonary arterial pressure obtained by right heart catheterization correlated poorly with the morphometric criteria obtained.     

CT肺动脉成像评价慢性血栓栓塞性肺动脉高压栓塞指数及右心功能

目的：以选择性肺动脉造影及右心导管为标准,探讨多层螺旋计算机断层肺动脉成像（CTPA）评价慢性血栓栓塞性肺动脉高压（CTEPH）及右心功能的价值。方法：回顾性收集确诊CTEPH的患者24例,均行右心导管及肺动脉造影、CTPA及超声心动图检查。结果：CT Qanadli栓塞指数为（37.16±8.77）%,CT Mastora栓塞指数为（38.14±21.56）%,Qanadli栓塞指数高于Mastora栓塞指数（Z=-4.107,P=0.000）,且二者正相关（r=0.734,P=0.000）。CTPA测得主肺动脉/升主动脉直径比与右心导管测定肺动脉平均压（mean pulmonary arterial pressure,mPAP）正相关（r=0.461,P=0.036）。CTPA测定右心室前壁厚度与mPAP成正相关（r=0.515,P=0.018）。CTPA测得肺动脉直径大于超声测肺动脉内径（t=3.485,P=0.002）,且正相关（r=0.588,P=0.002）。CTPA测得右心室最大短轴直径大于超声测右室横径（t=2.647,P=0.016）,且正相关（r=0.429,P=0.031）。CTPA测定右室前壁厚度小于超声测值（t=3.768,P=0.001）,且成正相关（r=0.551,P=0.004）。CTPA测室间隔厚度略低于超声测室间隔厚度（t=2.941,P=0.007）,两组资料正相关（r=0.751,P=0.000）。Qanadli栓塞指数和Mastora栓塞指数与肺动脉压、主肺动脉直径、肺动脉/主动脉直径比、右室横径、右室前壁厚度等参数均无相关性（P〉0.05）。结论：CT肺动脉造影不仅能够明确诊断慢性血栓性肺栓塞,而且能够提供肺动脉树的阻塞程度、右心功能改变信息,为临床决策和治疗提供更多的信息,但慢性血栓性肺动脉高压肺栓塞程度与右心功能无关。     

The relationship between pulmonary artery pressure and pulmonary artery diameter in pulmonary hypertension

The pulmonary arteries dilate in response to many factors, principally increased pressure and flow. In patients who have pulmonary arterial hypertension but no increase in flow, we have compared main pulmonary artery size at computed tomography with pulmonary haemodynamic data obtained during right heart catheterisation. In patients with primary pulmonary hypertension and chronic thromboembolic pulmonary hypertension, dilatation correlated with raised pulmonary vascular resistance and reduced cardiac output but not with mean arterial pressure. In patients with chronic lung disease no correlations were shown though a trend between raised pressure and size was observed. We speculate that pulmonary artery compliance is an important factor which determines the degree of dilatation in response to raised pressure. Estimations of pressure cannot be made from measurements of pulmonary artery size without knowledge of the underlying lung disease.     

Pulmonary arterial hypertension: a contemporary review

Pulmonary arterial hypertension has many causes, only some of which are well understood. The radiographic findings in pulmonary arterial hypertension are very similar regardless of the cause. Some radiographic features such as cardiac chamber enlargement, occur secondary to elevation of pulmonary pressures. In addition, sequential radiographs may demonstrate dramatic changes as the hypertension develops. This article presents examples of the various forms of pulmonary arterial hypertension, with pathologic correlation. Included are chronic pulmonary thromboembolism, plexogenic pulmonary arteriopathy, pulmonary venooclusive disease and persistent fetal circulation. Examples of lesions causing secondary pulmonary arterial hypertension: parenchymal lung disease, pulmonary venous hypertension, and congenital heart disease, are also illustrated.     

肺癌侵犯中央肺动脉继发肺低灌注的CT与DSA对照研究

目的　探讨肺癌侵犯中央肺动脉继发肺低灌注的CT特征及其诊断价值。方法　对2 0例手术及病理证实的肺癌侵犯中央肺动脉 (cancerousinvasionofcentralpulmonaryarteriesinlungcancer,CICPA)患者术前肺血管DSA及增强螺旋CT(含高分辨率CT ,即HRCT)征象行前瞻性对照研究。根据DSA和CT胸膜下末梢肺动脉分布和数量变化 ,即肺血管征、肺毛细血管充盈度和肺实质强化后密度及时间 密度曲线变化 (即肺实质征 ) ,行两者间的盲法对照 ,统计学分析CT与DSA征象及其一致性 ,评估CT对CICPA继发肺低灌注的诊断价值。结果　 2 0例手术病理证实的CICPA病例中 ,共3 0支肺叶动脉受累 ,DSA显示 90 % (2 7/3 0 )出现肺叶低灌注征象 ,CT诊断肺低灌注敏感度为 78%(2 1/2 7) ,特异度 10 0 % (3 /3 ) ,准确度 80 % (2 4/3 0 )。肺低灌注与CPA狭窄程度无明显相关性 (rs=0 40 ,P =0 0 73 )。CT与DSA的肺血管征一致性较好 (Kappa =0 69,P <0 0 0 1) ,而肺实质征一致性稍差 (Kappa =0 3 7,P =0 0 11)。结论　肺低灌注是肺癌侵犯中央肺动脉的常见表现 ,CT对其定性诊断具有重要价值 ,而定量判断有一定限度     

Metabolic lung disease: imaging and histopathologic findings

Metabolic lung disease includes pulmonary alveolar proteinosis (PAP), pulmonary amyloidosis, metastatic pulmonary calcification, dendritic pulmonary ossification, pulmonary alveolar microlithiasis, and storage diseases. In pulmonary alveolar proteinosis, CT demonstrates air-space consolidation with thickened interlobular septa, producing the so-called "crazy paving" appearance. Pulmonary amyloidosis can appear as parenchymal nodules (nodular parenchymal form), diffuse interstitial deposit (diffuse interstitial form), or submucosal deposits in the airways (tracheobronchial form). Metastatic pulmonary calcification may appear on high-resolution CT as numerous 3- to 10-mm diameter calcified nodules or, more commonly as fluffy and poorly defined nodular opacities. In pulmonary microlithiasis, high-resolution CT demonstrates diffuse punctuate micronodules showing slight perilobular predominance resulting in apparent calcification of interlobular septa. Niemann-Pick disease appears as ground-glass attenuation in the upper lung zone and thickening of the interlobular septa in the lower lung zone. Radiologic study including high-resolution CT will be helpful for the diagnosis and follow-up of these diseases.     

心脏磁共振评估肺动脉高压的研究进展

肺动脉高压（PH）是一组恶性进展性疾病,可以导致右心衰竭甚至死亡,因此对其进行早期诊断和评估至关重要。心脏磁共振（CMR）作为评估心血管的“一站式”检查,不仅可以采用多参数对PH病人心脏结构、功能、血流动力学及心肌组织特征等进行评价,还可以鉴别不同类型的PH,在PH的诊疗评估中发挥着重要作用,特别是基于CMR的人工智能的应用更是成为PH临床实践的新方向。     

Tei指数评价高海拔地区肺动脉高压患者右心功能的临床研究

目的：探讨Tei指数评价高海拔地区肺动脉高压患者右心功能的临床价值。方法：对西宁地区48例肺动脉高压患者和33例正常人,行超声检查,测量右房横径、右室横径、右室前壁厚度、肺动脉主干内径根据三尖瓣返流和肺动脉瓣返流估测肺动脉收缩压、肺动脉舒张压、肺动脉平均压,并计算右心Tei指数。结果：肺动脉高压患者与对照组右心Tei指数有显著统计学差异,不同肺动脉压力组之间右心Tei也有统计学差异。结论：右心Tei指数是反映右心整体功能较敏感的指标。     

Ischemia of right ventricle and cor pulmonale

48 year old man with chronic obstructive pulmonary disease (COPD) secondary to pulmonary hypertension with domiciliary non-invasive ventilation was seen. He came to the emergency department with acute exacerbation of COPD. The patient was admitted to the Cardiology Service with the diagnosis of congestive heart failure. Diagnostic imaging (chest X-ray, transthoracic Doppler-echocardiography, multidetector row spiral CT and myocardial perfusion imaging) revealed an enlarged right ventricle. ECG was consistent with right ventricular failure. The heart perfusion imaging (pharmacologic stress testing with dobutamine) showed cor pulmonale and right ventricle ischemia induced by drug stress with dobutamine. Although right ventricle myocardial chronic dysfunction rarely causes right ventricular failure, it can occur when cor pulmonale and ischemia heart disease are present.     

Pulmonary artery and right ventricle assessment in pulmonary hypertension: correlation between functional parameters of ECG-gated CT and right-side heart catheterization

Background Right ventricular function predicts outcome in patients with pulmonary hypertension (PH). Therefore accurate assessment of right ventricular function is essential to graduate severity, assess follow-up, and response to therapy. Purpose To evaluate whether PH severity could be assessed using electrocardiography-gated CT (ECG-gated CT) functional parameters. A further objective was to evaluate cardiac output (CO) using two ECG-gated CT methods: the reference Simpson technique and the fully automatic technique generated by commercially available cardiac software. Material and Methods Our institutional review board approved this study; patient consent was not required. Twenty-seven patients who had undergone ECG-gated CT and right heart catheterization (RHC) were included. Two independent observers measured pulmonary artery (PA) diameter, PA distensibility, aorta diameter, right ventricular cardiac output (CT-RVCO) and right ventricular ejection fraction (CT-RVEF) with automatic and Simpson techniques on ECG-gated CT. RHC-CO and mean pulmonary arterial pressure (mPAP) were measured on RHC. Relationship between ECG-gated CT and RHC measurements was tested with linear regression analysis. Results Inter-observer agreement was good for all measurements (r > 0.7) except for CT-RVCO calculated with Simpson's technique (r = 0.63). Pulmonary artery (PA) distensibility was significantly correlated to mPAP (r = -0.426, P = 0.027). CT-RVEF was correlated with mPAP only when issued from Simpson technique (r = -0.417, P = 0.034). CT-RVEF was not significantly correlated to RHC-CO (P > 0.2). CT-RVCO measured with Simpson technique (r = 0.487, P = 0.010) and automatic segmentation (r = 0.549, P = 0.005) correlated equally with RHC-CO. Conclusion CT-RVEF and CT-RVCO measured on ECG-gated CT are significantly correlated, respectively, to mPAP and RHC-CO in this population with severe reduction of the right ventricular ejection fraction and could be useful for evaluating and following patients with PH.     

慢性缺氧性肺动脉高压大鼠心、肺心钠素代谢变化及其机制的探讨

观察慢性缺氧性肺动脉高压(CHPAH)大鼠心,肺心钠素代谢变化,结果表明CHPAH大鼠右心室、肺组织、肺灌流液及动脉血血浆心钠素(ANP)含量较对照组显著增加(P<0.01),但右房心肌组织ANP含量与对照组相比无显著差异(P>0.05).结果提示CHPAH大鼠心,肺合成分泌ANP代偿性增强,其中,以右心室尤为显著.肺脏不仅合成ANP,而且分泌入血,影响循环血ANP水平.     

Pulmonary artery dissection in long standing idiopathic pulmonary arterial hypertension: A case report

Pulmonary arterial dissection (PAD) is a rare and often lethal complication of chronic pulmonary arterial hypertension (PAH), which may occurs in patients with idiopathic pulmonary arterial hypertension (IPAH) and potentially in those with connective tissue disorders. While rare, sudden death often occurs secondary to acute cardiac tamponade, as the pulmonary artery dissects into the pericardium; this diagnosis is often made postmortem. Nevertheless, with the proliferation of multidetector computed tomography (MDCT) as a diagnostic test, patients may be identified very early after symptom onset, prompting rapid intervention with decreased morbidity and mortality. We report a case of IPAH complicated by pulmonary artery aneurysm (PAA) and PAD, diagnosed by CT pulmonary angiogram (CTPA), and treated with bilateral lung transplantation, pulmonic valve replacement, and re-anastomosis of the donor main PA to a pulmonary valve conduit.     

Transcatheter occlusion of pulmonary arterial circulation and collateral supply: failures, incidents, and complications

Failures and complications were analyzed retrospectively in 45 patients treated with embolotherapy or occlusion of pulmonary arterial circulation. Pulmonary arterial branches were occluded with steel coils in 19 patients with pulmonary arteriovenous malformations, 17 with hemoptysis of pulmonary artery (PA) origin, and one with massive parenchymal shunt. Bronchial arterial supply to the lung was embolized with small particles in eight cases of hemoptysis and systemic to pulmonary arterial antegrade shunt secondary to chronic thromboembolism. Asymptomatic incidents included catheterization failures, vascular damage, partial occlusion, partial recanalization of the thrombus, ectopic deposition of a coil, and delayed bacterial contamination of the thrombus. A few cases of transient clinical and radiologic signs of pulmonary infarction were observed after complete occlusion of the PA and bronchial artery embolization. This complication was never observed after complete occlusion of main right or left PA, inferior right or left PA, or segmental branches. The management and prevention of these complications, the role of bronchial arterial collateral pathways, and the importance of the site of PA occlusion in the development of pulmonary infarction are discussed.     

Computed tomography in chronic interstitial lung disease

A number of studies have demonstrated that high resolution computed tomography (CT) is superior to the radiography in the assessment of patients who have chronic interstitial lung disease. CT may demonstrate extensive parenchymal disease when the radiograph is normal and may allow for a confident diagnosis when the radiographic findings are nonspecific. Although well over 100 different diseases may involve the pulmonary interstitium, in practice, approximately 10 diseases account for 80% to 90% of all cases. This article reviews the CT manifestations of the most common chronic interstitial lung diseases.