多排螺旋CT心电门控技术对肺静脉口径的研究

目的 利用多排螺旋CT(MDCT)心电门控技术评价1个心动周期内肺静脉口径的变化.方法 前瞻性收集25例利用回顾性心电门控技术进行扫描的检查者,进行10个时相的肺静脉重建.首先在横断位同一层面上测量出右下肺静脉(RIPV)各个时相的口径,得出其最大值及最小值所对应的2个时相,然后在这2个时相下运用多种后处理技术重建4条肺静脉,最后分别测量其口径最大值与最小值并进行统计学分析.结果 横断面上右下肺静脉最大值出现在35%时相(16.21±2.53),最小值出现在85%时相(13.29±2.11);4条肺静脉口径在35%时相的最大值与85%时相最小值比较具有统计学意义(P<0.01).结论 MDCT心电门控技术可以更准确描述肺静脉口径,在1个心动周期内肺静脉口径呈现周期性变化.     

64层螺旋CT对肺静脉异位引流的诊断价值

目的 探讨肺静脉异位引流的64层螺旋CT及后处理图像征象,以提高对该病的诊断价值.资料与方法 回顾性分析16例先天性肺静脉异位引流患者的64层螺旋CT图像在工作站进行多半面重组(MPR)、最大密度投影(MIP)和容积再现(VR)等后处理资料,观察异位引流肺静脉的位置、形态、其异位连接(心腔或静脉)以及合并的心脏畸形,并对8例行手术治疗病例的CT诊断、超声心动图检查与手术结果进行比较.结果 64层螺旋CT诊断完全性肺静脉异位引流8例,其中心上型5例,心内型3例;部分性肺静脉异位引流8例,其中心上型4例,心内型4例.8例手术病例CT诊断与手术结果完全相符.结论 64层螺旋CT在诊断肺静脉异位引流中具有重要作用,是肺静脉异位引流的有效、无创检查方法.     

Reliability of MDCT in characterizing pulmonary venous drainage, diameter and distance to first bifurcation: an interobserver study

RATIONALE AND OBJECTIVES: To evaluate the interobserver agreement of readers in evaluating pulmonary venous anatomy and in measuring pulmonary vein ostial diameters and distance to first bifurcation. MATERIALS AND METHODS: This study was approved by our institutional review board. Thin-section contrast material-enhanced multidetector computed tomography examinations of the thorax were retrospectively reviewed in 200 consecutive patients (38 females and 162 males), age 24-79 years (mean, 52.8) referred for imaging before radiofrequency ablation therapy for atrial fibrillation. For each patient, pulmonary venous anatomy and drainage patterns including the number of venous ostia was assessed independently by experienced cardiothoracic radiologists. Pulmonary vein ostial diameter and distance to the first bifurcation of the four major pulmonary veins (right inferior and superior, left inferior and superior), the middle lobe pulmonary vein, and any anomalous pulmonary veins (common trunks and accessory veins) were measured independently at a workstation. Interreader assessment of pulmonary venous anatomy was evaluated using the Kappa statistic. Interreader variation in measurements of venous diameter and distant to first bifurcation were estimated by Bland-Altman plots and Pitman's test of difference in variance. RESULTS: Very good to excellent interreader agreement in detection of anomalous pulmonary venous anatomy, middle lobe pulmonary venous drainage, and other thoracic venous anomalies. No significant variation between readers in pulmonary vein ostial diameter measurements for the four major and middle lobe pulmonary veins, or the anomalous pulmonary veins. Significant interreader variability was noted in measurements of the pulmonary vein distance to first bifurcation for the right inferior (P = .017), middle lobe (P = .005), and left inferior (P = .015) pulmonary veins. CONCLUSIONS: There is excellent interobserver agreement when evaluating normal and anomalous pulmonary venous drainage patterns, and when measuring normal or anomalous pulmonary vein diameters. However, measurements of distances to first bifurcation were less reliable across readers.     

右房密度监测触发 CT 肺动脉成像

目的：通过对右房(RA)CT 值的监测,寻找其达峰时间,优化 CT 肺动脉成像(CTPA)显像。方法采集拟行 CTPA 的患者60例,随机分成2组,肺动脉触发(PT)组(n=30)：注射70 mL 对比剂(CA)并屏气,采用肺动脉干 CT 值监测触发方式获取CTPA 图像;RA 组(n=30)：注射40 mLCA,自由呼吸,并采用 RA 监测触发方式。对图像质量、肺动脉及肺静脉 CT 值、肺动脉-肺静脉密度差值等进行对比。结果RA 组图像质量、肺动脉平均值及肺动脉-肺静脉密度差明显高于 PT 组(P <0.05),而 RA 组肺静脉 CT 值更低(P <0.05)。肺动脉6级分支显示比例2组无统计学差异(P >0.05)。结论自由呼吸状态下基于 RA 密度监测触发的 CTPA 能在肺静脉 CT 值最低时使肺动脉得到最大强化,且 CA 使用量减少。     

Bird's Nest filter placement within an enlarged hemiazygos vein for prevention of pulmonary embolism

Thrombosis of the inferior vena cava (IVC) may result in considerable enlargement of paravertebral, azygos, and hemiazygos collateral veins that may in turn serve as pathways for thromboemboli to the pulmonary circulation. Herein we describe the transfemoral placement of a Bird's Nest filter within an enlarged hemiazygos vein to provide prophylaxis against pulmonary embolism in a patient with right femoral venous thrombosis who could not tolerate systemic anticoagulation. There had been earlier transjugular placement of a Greenfield filter within the suprarenal IVC.     

Systemic-to-pulmonary venous shunt in superior vena cava obstruction: depiction on computed tomography venography

Purpose: To describe computed tomography (CT) venographic appearances of systemic-to-pulmonary venous shunts with CT venography and three-dimensional reconstruction images from patients with superior vena cava obstruction.

Material and Methods: From January 1994 to April 2002, CT venography was performed in 45 patients with superior vena cava obstruction using a single-detector helical CT scanner (n=38) and four-detector row CT scanner (n=7). Analysis of CT scan data included the cause and degree of venous obstruction, the presence of pleural thickening and enhancement, and the attenuation of pulmonary veins. The causative factor for systemic-to-pulmonary venous shunt was evaluated using the Fisher exact test.

Results: Systemic-to-pulmonary venous shunts were observed in four patients (9%) who had high-attenuated pulmonary veins and pleural enhancement on CT venography. Pleural thickening (P=0.01) and a history of pulmonary tuberculosis (P=0.034) are statistically significant risk factors.

Conclusion: CT venography showed strong pleural enhancement and high-attenuated pulmonary veins indicating systemic-to-pulmonary venous shunts. Radiologists should study the earlier enhancement of pulmonary veins in patients with superior vena cava obstruction.     

Scimitar syndrome: confirmation of diagnosis by a noninvasive technique (MRI)

Scimitar syndrome is a rare congenital pulmonary anomaly that is characterized by hypoplasia of the right lung and the right pulmonary artery with anomalous pulmonary venous drainage to the inferior vena cava or the right atrium. Very few reports are available that analyze the value of magnetic resonance imaging (MRI) in establishing the diagnosis. We present a case with Scimitar syndrome in which anomalous pulmonary venous return was confirmed by cine MRI.     

Superior Vena Cava Syndrome Associated with Right-to-Left Shunt through Systemic-to-Pulmonary Venous Collaterals

Superior vena cava (SVC) obstruction is associated with the gradual development of venous collaterals. We present a rare form of systemic-to-pulmonary subpleural collateral pathway that developed in the bridging subpleural pulmonary veins in a 54-year-old woman with complete SVC obstruction. This uncommon collateral pathway represents a rare form of acquired right-to-left shunt due to previous pleural adhesions with an increased risk of stroke due to right-to-left venous shunting, which requires lifelong anticoagulation.     

Partial anomalous pulmonary venous return with secundum atrial septal defect: A case report

Partial anomalous pulmonary venous return (PAPVR) is a congenital heart anomaly in which some of the pulmonary veins return to the right atrium or one of its supplying veins instead of normally connecting with the left atrium. Oftentimes it is concurrent with a secundum atrial septal defect. PAPVR is typically asymptomatic, however symptoms of pulmonary hypertension can arise at higher degrees of left-to-right shunting. An 80-year-old male presented with exertional dyspnea and was found to have a secundum atrial septal defect on echocardiogram. A subsequent contrast enhanced computed tomography of the chest revealed a concomitant PAPVR.     

Venous thromboembolism: additional diagnostic value and radiation dose of pelvic CT venography in patients with suspected pulmonary embolism

Purpose

To assess the additional diagnostic value of indirect CT venography (CTV) of the pelvis and upper thighs performed after pulmonary CT angiography (CTA) for the diagnosis of venous thromboembolism (VTE).

Materials and methods

In a retrospective analysis, the radiology information system entries between January 2003 and December 2007 were searched for patients who received pulmonary CTA and additional CTV of the pelvis and upper thighs. Of those patients, the radiology reports were reviewed for the diagnosis of pulmonary embolism (PE) and deep venous thrombosis (DVT) in the pelvic veins and veins of the upper thighs. In cases with an isolated pelvic thrombosis at CTV (i.e. which only had a thrombosis in the pelvic veins but not in the veins of the upper thigh) ultrasound reports were reviewed for the presence of DVT of the legs. The estimated radiation dose was calculated for pulmonary CTA and for CTV of the pelvis.

Results

In the defined period 3670 patients were referred to our institution for exclusion of PE. Of those, 642 patients (353 men, 289 women; mean age, 65 ± 15 years, age range 18–98 years) underwent combined pulmonary CTA and CTV. Among them, PE was found in 227 patients (35.4%). In patients without PE CTV was negative in all cases. In patients with PE, CTV demonstrated pelvic thrombosis in 24 patients (3.7%) and thrombosis of the upper thighs in 43 patients (6.6%). Of those patients 14 (2.1%) had DVT in the pelvis and upper thighs. In 10 patients (1.5%) CTV showed an isolated pelvic thrombosis. Of those patients ultrasound reports were available in 7 patients, which revealed DVT of the leg veins in 5 cases (1%). Thus, the estimated prevalence of isolated pelvic thrombosis detected only by pelvic CTV ranges between 1–5/642 patients (0.1–0.7%). Radiation dose ranges between 4.8 and 9.7 mSv for additional CTV of the pelvis.

Conclusion

CTV of the pelvis performed after pulmonary CTA is of neglectable additional diagnostic value for the detection of VTE, because the additional radiation dose is high and isolated pelvic DVT is very rare. Venous imaging of the legs (preferably by radiation-free ultrasound) is sufficient for the diagnosis of underlying DVT in patients with suspected PE.     

核素肺灌注显像对急性肺栓塞诊断的临床价值

目的评价放射性核素肺灌注显像在诊断急性肺动脉栓塞中的价值。方法对临床怀疑有急性肺动脉栓塞的25例患者进行了放射性核素肺灌注显像,同时行双下肢深静脉显像。结果25例患者中有23例出现不同程度的多发肺段血流灌注异常,其中41个肺段出现放射性缺损区,84个肺段出现放射性稀疏区。25例患者6例双下肢深静脉血栓形成。结论放射性核素肺灌注显像是诊断急性肺动脉栓塞的一种无创伤性的有效的检查方法。     

Normative analysis of pulmonary vein drainage patterns on multidetector CT with measurements of pulmonary vein ostial diameter and distance to first bifurcation

RATIONALE AND OBJECTIVES: To document the frequency of normal and anomalous drainage patterns of the pulmonary veins, and to establish normal values for pulmonary vein ostial diameters, and distance to first bifurcation using multidetector computed tomography, as pertinent to ablation procedures for atrial fibrillation. MATERIALS AND METHODS: Two cardiothoracic radiologists retrospectively reviewed thin-section contrast material-enhanced multidetector computed tomography examinations of the thorax in 200 consecutive patients (38 females and 162 males), age 24-79 years (mean 52.8) referred for imaging before radiofrequency ablation therapy for atrial fibrillation. Pulmonary vein anatomy was based on both the number of venous ostia and the drainage patterns of pulmonary veins. Pulmonary vein ostial diameters and distance to first bifurcation of the four major pulmonary veins (right inferior and superior, left inferior and superior) and any additional pulmonary veins were measured at a workstation using both axial images and multiplanar reconstructions by two experienced cardiothoracic radiologists; the mean pulmonary vein diameter and the shortest distance to first bifurcation of the two measurements are reported. RESULTS: The majority of patients, 82% (164 patients) had four pulmonary veins, with a superior and inferior ostium on the right and a superior and inferior ostium on the left. Of the remainder, 9% (18 patients) had five veins, 4.5% (9 patients) had three veins, 3% (6 patients) had two anomalies each, and 0.5% (1 patient) had three anomalies. The middle lobe pulmonary vein drained into the right superior pulmonary vein in 83.5% of patients, directly into the left atrium in 11% of patients, and into the right inferior pulmonary vein in 5.5% of patients; 6.5% of patients had a single left pulmonary vein ostium. Mean pulmonary vein diameters with 95% confidence intervals at the ostia were as follows: right superior 17.6 (13.64-15.36) mm; left superior 16.6 (16.03-17.08) mm; right inferior 17.1 (16.58-17.55) mm; left inferior 14.8 (14.25-15.27) mm, and independent middle lobe 8.6 (8.27-8.86) mm. Mean distance to first bifurcation with 95% confidence intervals were: right superior 14.5 (17.02-18.23) mm; left superior 17.6 (16.63-18.53) mm; right inferior 7.0 (6.49-7.46) mm; left inferior 13.5 (12.83-14.16) mm, and independent middle lobe 8.4 (7.7-9.17) mm. CONCLUSION: Thin-section thoracic computed tomography demonstrates a greater variability of pulmonary venous drainage than previously described. There is greater variability of the right lung venous drainage compared to the left lung. Eighty-two percent of people have four standard pulmonary veins. There is significant variability in pulmonary vein diameter and distance to first bifurcation.     

Transcatheter aspiration: the key to successful percutaneous treatment of deep venous thrombosis?

RATIONALE AND OBJECTIVES: The purpose of this study was to examine transcatheter aspiration as an adjunct to local thrombolysis in a porcine model of acute deep venous thrombosis (DVT). MATERIALS AND METHODS: DVT was induced in both hind limbs of five pigs. Thirty minutes later, bilateral thrombolysis was performed by using infusion guidewires placed coaxially through occlusion balloon catheters. A temporary venous filter was then placed in the inferior vena cava. The balloon catheters and infusion wire were removed, a 14-F sheath was placed on the right side, and aspiration of residual thrombi was attempted with 8- and 6-F catheters. At autopsy, the mass of any thrombus in the iliofemoral veins was measured, and residual thrombosis in the venous tributaries was graded at four sites. Thromboemboli in the inferior vena cava and the pulmonary circulation were also collected and weighed. RESULTS: With aspiration and lysis, the iliofemoral veins were cleared of thrombus in three of five limbs; from the remaining two, only 0.09 and 0.15 g of thrombus were harvested. Except for the deep femoral vein in two legs, tributaries were free of thrombus. After thrombolysis alone, thrombi ranged in mass from 0.54 to 1.14 g (median, 0.70 g). Some thrombi were observed in most tributaries. One or two small emboli were found trapped by the caval filter and in the pulmonary circulation in four and three pigs, respectively. CONCLUSION: The primary axial veins and their tributaries can be rapidly cleared of thrombus by using thrombolysis with transcatheter aspiration, but this procedure is associated with the risk of pulmonary embolism.     

MR imaging of partial anomalous pulmonary venous connections

Magnetic resonance imaging was performed on 11 patients with partial anomalous pulmonary venous connections (PAPVC). Ten of these patients also had echocardiographic examinations, eight of which included color-flow Doppler studies. The diagnosis of PAPVC was confirmed in each of these patients by surgery or angiography. Fourteen anomalous pulmonary venous connections were identified, 10 involving the right upper lobe pulmonary vein and 4 involving the left upper lobe pulmonary vein. This retrospective review demonstrated that all 14 anomalous venous connections were correctly identified by MR imaging, whereas only 8 of 13 (62%) were identified by echocardiography. With MR, 89% of all the pulmonary veins and 93% of the anomalous pulmonary veins were visualized on axial images, while 41% of all pulmonary veins and 71% of anomalous veins were seen on coronal MR images. There were five atrial septal defects (ASDs), four of the sinus venous type and one of the septum secundum type. All five ASDs were correctly identified with MR imaging; three of four ASDs were identified with echocardiography. We conclude that MR imaging provides an accurate noninvasive method of depicting the anatomic abnormalities associated with PAPVC.     

Embolization during treatment of deep venous thrombosis: incidence, importance, and prevention

The standard of care for the treatment of acute deep venous thrombosis (DVT) is anticoagulation, which often prevents the formation of new thrombus and reduces the risk of pulmonary embolism (PE) but fails to eliminate the clot burden. Patients who have thrombus remaining in their deep venous system despite therapeutic anticoagulation are at high risk for developing symptoms of the postthrombotic syndrome, a debilitating condition that adversely affects their quality of life. Strategies of thrombus removal for acute DVT, such as operative thrombectomy, catheter-directed thrombolysis, and pharmacomechanical techniques, are designed to avoid postthrombotic morbidity by restoring patency to the deep veins, but there is concern that these techniques may result in fragmentation of clot and pulmonary embolization. Careful patient evaluation before treatment is essential for preventing complications and often reveals asymptomatic pulmonary emboli in as many as 50% of patients. Nonobstructive or free-floating thrombus in the vena cava is a risk factor for procedure-related embolization and is frequently an indication for the use of vena caval filtration. A review of the literature on acute DVT treated by anticoagulation alone or with strategies of thrombus removal reveals that pulmonary embolization is an infrequent occurrence. Treatment with anticoagulation alone, however, increases the risk of patients developing symptoms of the postthrombotic syndrome, whereas thrombus removal strategies reduce postthrombotic morbidity without increasing the risk of embolization.     

Dilated pulmonary venous confluence presenting as a mass in mitral stenosis

Pulmonary varices are rare venous anomalies which typically present as masses. Since they are usually clinically insignificant, varices must be diagnostically distinguished from parenchymal tumors and mediastinal adenopathy so one may adhere to a conservative medical approach. This report reviews the literature and illustrates a convergence of varices that presented as a larger sized mass than previously described by others.     

Individual Pulmonary Vein Atresia in Adults: Report of Two Cases

We present two cases of individual pulmonary vein atresia without vestige of an involved pulmonary vein. On CT, we noted the absence or interruption of normal pulmonary venous structures, and the presence of abnormal vascular structures that represented collaterals for the involved lung parenchyma. On angiography, the atretic pulmonary vein was found to drain into the other ipsilateral pulmonary veins through the collaterals.     

Unilateral pulmonary vein atresia: Literature overview and case report

The unilateral absence of the pulmonary vein, known as pulmonary vein atresia, is a rare type of unilateral pulmonary venous hypoplasia caused by the congenital atrophy of the long pulmonary vein segments in one lung. The involved lung may be normal in size or present with hypoplasia and is often characterized by increased interstitial attenuation and interlobular septal thickening due to venous stasis, edema, and fibrosis. Pulmonary angiography often reveals a reduced size for the lateral pulmonary artery, peripherally sparse pulmonary vessels, contrast stasis, and the inability to visualize pulmonary veins. Symptoms include coughing up blood and infection. We present the clinical case of a patient who was initially diagnosed with recurrent hemoptysis due to pulmonary tuberculosis, followed by unsuccessful treatment. Imaging by 64-slice computed tomography with contrast injection using multiplanar reformation and volume rendering techniques allowed this case to be definitively diagnosed. This report emphasizes the epidemiological factors and clinical and imaging features of unilateral pulmonary vein atresia to prevent confusion and facilitate proper diagnosis in similar cases.     

Deep venous thrombosis with suspected pulmonary embolism: detection with combined CT venography and pulmonary angiography

PURPOSE: To determine the frequency and location of deep venous thrombosis at computed tomographic (CT) venography after CT pulmonary angiography in a large series of patients clinically suspected of having pulmonary embolism and to compare the accuracy of CT venography with lower-extremity venous sonography. MATERIALS AND METHODS: Venous phase images were acquired from the diaphragm to the upper calves after completion of CT pulmonary angiography in 650 patients (373 women, 277 men; age range, 18-99 years; mean age, 63 years) to determine the presence and location of deep venous thrombosis. Results of CT venography were compared with those of bilateral lower-extremity venous sonography in 308 patients. RESULTS: A total of 116 patients had pulmonary embolism and/or deep venous thrombosis, including 27 patients with pulmonary embolism alone, 31 patients with deep venous thrombosis alone, and 58 patients with both. Among 89 patients with deep venous thrombosis, thrombosis was bilateral in 26, involved the abdominal or pelvic veins in 11, and was isolated to the abdominal or pelvic veins in four. In patients in whom sonographic correlation was available, CT venography had a sensitivity of 97% and a specificity of 100% for femoropopliteal deep venous thrombosis. CONCLUSION: Combined CT venography and pulmonary angiography can accurately depict the femoropopliteal deep veins, permitting concurrent testing for venous thrombosis and pulmonary embolism. CT venography also defines pelvic or abdominal thrombus, which was seen in 17% of patients with deep venous thrombosis.