May-Thurner综合征的医学成像研究进展

May-Thurner综合征（MTS）是引起下肢静脉血栓形成和肺栓塞等并发症的主要原因之一,发病率常被低估。血管内超声诊断结果可靠,同时能进行腔内治疗,但费用昂贵;MR成像在判断髂静脉受压程度上有明显夸大;CT和DSA应用较广,是诊断MTS的主要标准;间接法CT静脉成像操作方便,应用较广;直接法CT静脉成像存在边流效应,应用较少;DSA能同时实施支架置入术或球囊扩张术以进行治疗。就以上几种医学成像方法研究进展予以综述。     

MRI in venous thromboembolic disease

We evaluated the ability of magnetic resonance (MR) imaging to detect deep venous thrombosis (DVT) and pulmonary embolism (PE). MR venography was performed on 217 patients suspected of having DVT. Cine-MR imaging of the pulmonary arteries was performed in 14 other patients who were thought to have PE based on other imaging studies. In a third group of 5 patients, MR pulmonary angiograms were performed in the sagittal and coronal planes with a multislice fast gradient recalled echo technique. All but one of the 217 MR venograms were technically adequate. In 72 patients with correlative imaging studies (venography and ultrasound) MR venography was 99% sensitive and 95% specific. On the basis of follow-up (mean 8.3 months), no false-negative MR venograms were detected in an additional 64 patients. In 11 other patients MR revealed a diagnosis other than DVT. Cine-MR showed PE in all 14 patients evaluated. MR pulmonary arteriography demonstrated filling defects consistent with acute PE in 2 of 3 patients with acute PE; in the third patient only a questionable filling defect was seen. Coarctations or webs were found in the pulmonary arteries of both patients with chronic PE. These preliminary data suggest that MR imaging may be able to evaluate both the peripheral venous and the pulmonary arterial component of venous thromboembolic disease. Further technical refinement and more extensive clinical experience will be required to establish the role of this method in diagnosing pulmonary embolism, but MR venography is now used routinely in our hospital for the diagnosis of deep venous thrombosis. Correspondence to: H. D. Sostman     

动态3D CE-MRV在颅内疾病诊断及治疗中的应用初探

目的：探讨动态3D CE-MRV在颅内静脉系统疾病诊断中的成像优势及其对颅内疾病临床诊断及治疗的指导意义.方法：可疑或确诊为颅内静脉病变者36例应用3T磁共振仪及3D TRICK技术行动态CE-MRV检查,9例无颅内静脉病变者同时行2D TOF序列MRV检查.分析动态3D CE-MRV图像,观察颅内深浅静脉系统主干及其分支的显示情况,比较其相对于2D TOF序列MRV的优势;分析动态3D CE-MRV对颅内疾病如静脉窦及静脉血栓、累及静脉的血管畸形、肿瘤和外伤等的诊断价值及其对临床治疗的指导意义.结果：与2D TOF序列比较,3D CE-MRV对静脉窦属支、上下吻合静脉及海绵窦等显示更清晰（P〈0.05）.动态CE-MRV显示36例受检者大致可分为4种结果：①正常者16例,含静脉发育变异6例;②累及静脉的颅内血管畸形3例;③静脉窦或静脉血栓11例,其中3例为溶栓术后复查显示再通;④肿瘤及外伤6例：脑膜瘤或颈静脉球瘤压迫或侵犯静脉窦者3例;外伤致颅内静脉异常者3例,其中1例为颈内动脉海绵窭瘘.结论：动态3D CEMRV对颅内静脉尤其是细小静脉的观察明显优于2D TOF序列的MRV;多时相显影和多方位重组可对颅内静脉变异、静脉畸形和累及静脉的疾患能清晰显示,为临床诊断、治疗方案的确定及疗效评价提供重要的影像依据.     

Bildgebende Diagnostik von Erkrankungen der Venen

Diseases of the venous system are common. A variety of diagnostic imaging methods are available. Of these, ultrasound with color-coded duplex sonography is the preferred method in the diagnosis of vein diseases, especially in patients with suspected deep venous thrombosis (DVT) and varicosis. Compression sonography is a very accurate test in the diagnosis of DVT of the lower and upper extremities in symptomatic patients. Still today, phlebography is an important tool in the diagnosis of venous diseases. Computed tomography (CT) plays an important role in disorders of the superior and inferior vena cava and of the iliac vein. Today, the role of MR venography in vein diseases is limited.     

CT venography vs ultrasound in the diagnosis of thromboembolic disease in patients with clinical suspicion of pulmonary embolism

To assess the reliability of indirect computed tomography venography (CTV) in the detection of deep venous thrombosis (DVT) in patients with clinical suspicion of pulmonary embolism (PE). 235 consecutive patients with suspicion of PE underwent an imaging protocol composed of a CT pulmonary angiography (CTPA), a CTV and an ultrasound study of the deep venous system, which was considered the “gold standard.” Sensitivity, specificity, and predictive values were calculated for CTV. ith CTV, 30 (12.8%) cases of DVT were detected, 9 (3.8%) of them without pulmonary embolism in CTPA, increasing the diagnosis of thromboembolic disease in 3.8%. However, six of these nine diagnoses were false positives, and CTV missed six cases of DVT. CTV rendered a sensitivity of 58.8%, specificity of 95.0%, a positive predictive value of 66.7%, and a negative predictive value of 93.2%. In patients with clinical suspicion of pulmonary embolism, ultrasound is preferred to CTV for the detection of DVT.     

Deep venous thrombosis: comparison of indirect multidetector CT venography and sonography of lower extremities in 26 patients

OBJECTIVE: To compare the accuracy of indirect mutidetector row computed tomographic (MDCT) venography with lower extremity venous sonography for the diagnosis of femoropopliteal deep venous thrombosis (DVT), and to determine the frequency and location of DVT at MDCT venography. MATERIALS AND METHODS: Twenty-six consecutive patients suspected of having pulmonary embolism (PE) underwent both combined MDCT venography and MDCT pulmonary angiography and lower extremity venous sonography. Indirect MDCT venography was acquired from the upper calves to the mid-abdomen following MDCT pulmonary angiography. The CT venographic findings were compared with those of sonography for the diagnosis of femoropopliteal DVT. All CT scans were also reviewed for the frequency and location of DVT. RESULTS: Indirect MDCT venography disclosed DVT in 19 patients, and 12 of whom also had PE. Seventeen patients with thrombosis in the femoropopliteal veins were identified in both indirect MDCT venography and sonography. The sensitivity and specificity of indirect MDCT venography for femoropopliteal DVT, as compared with sonography, were both 100%. In one patient DVT in the superficial femoral vein was detected using only indirect MDCT venography. MDCT venography also showed superior extension of femoropopliteal DVT to the inferior vena cava and iliac veins in four patients and thrombosis isolated to the inferior vena cava and common iliac vein thrombosis in one patient. CONCLUSIONS: Indirect MDCT venography is as accurate as sonography in the diagnosis of femoropopliteal DVT. MDCT venography can further reveal thrombus in large pelvis veins and the inferior vena cava, an important advantage over sonographic screening for DVT.     

Current DVT imaging

Accurate diagnosis of deep venous thrombosis (DVT) is very difficult, and imaging plays a crucial role in the diagnosis or exclusion of DVT. The initial test of choice for diagnosis of acute thigh as well as upper extremity DVT is ultrasound, because of its high accuracy, relatively low cost, portability, and lack of ionizing radiation. In patients who are undergoing CT pulmonary angiography for suspected pulmonary embolism, CT venography can be performed as part of the examination, for comprehensive evaluation of the venous system in the legs, abdomen, and pelvis. MR has a problem-solving role, and conventional venography is now limited to specific scenarios including evaluation of central DVT in the upper extremities, as a prelude to intervention for thrombolysis/thrombectomy, and prior to placement of an inferior vena cava filter. This article discusses the imaging findings of DVT, and the role of these imaging examinations in the evaluation of patients with suspected DVT.     

脑内静脉窦血栓形成MRI表现的再探讨和MR静脉成像的选择

目的：明确脑内静脉血栓形成的脑内MRI表现和MR血管造影的诊断及检查方法。材料和方法：共9例病人，男性2例，女性7例。年龄30－56岁，平均38．2岁。使用Siemens-vision-plus超导高场MRI系统，场强1．5T。采用常规SE序列，tuberSE，TOF血管成像（用于动脉血管显示），PC法20静脉血管成像和增强3D静脉血管成像（用于矢状窦显示）。结果：MR的动脉血管成像显示阳性率为0％，2D和3D静脉血管成像阳性率为100％，3D增强静脉血管造影可更好地显示阻塞的静脉。脑实质内均有阳性表现，表现为矢状窦旁白质区对称或非对称性异常改变，呈斑片状和片状，T1W为低信号，T2W为高信号。增强后脑膜强化2例。合并脑内出血5例。结论：MRI结合MR静脉血管造影，尤其增强3D静脉血管造影是诊断脑内静脉血栓形成的有效手段。     

320排CT血管造影和超声诊断下肢深静脉血栓价值比较

目的：探讨320排容积 CT 静脉造影(CTV)和超声(US)对下肢深静脉血栓(DVT)的诊断价值。方法回顾性分析经DSA 证实为下肢 DVT 的患者51例,对比直接法 CTV 及 US 对下肢不同部位栓子的检出率。结果51例患者中,CTV 共诊断DVT 48例,发现栓子124处,US 诊断静脉血栓46例,发现栓子86处。其中盆腔 DVT CTV 检出34处,US 检出10处,胫腓静脉血栓 CTV 检出25处,US 检出5处,CTV 检出股深静脉血栓2处,US 检出11处。结论直接法 CTV 及 US 对下肢 DVT 的诊断均具有较高的临床应用价值,而前者对盆腔 DVT 及胫腓静脉血栓的检出率更高,而对股深静脉血栓的显示不及后者。     

先天性髂静脉受压综合征的静脉造影诊断

目的:探讨先天性髂静脉受压综合征的静脉造影诊断价值。材料和方法:回顾性分析经手术证实的18例先天性髂静脉受压综合征,其中8例行股静脉插管造影。结果:18例先天性髂静脉受压综合征的髂静脉造影表现均为静脉血管受压改变及侧支循环的形成。结论:先天性髂静脉受压综合征的髂静脉造影表现较典型,改变传统造影方式是发现并诊断C IVCS的关键。     

Direct contrast-enhanced 3D MR venography

Non-enhanced two-dimensional (2D) time-of-flight (TOF) MRA is well established for imaging of the deep venous system. However, based on the acquisition of multiple axial images, it can be time-consuming and often fails to delineate small superficial and perforating veins. The presented low-dose, direct-contrast-injection 3D MR venography technique allows rapid acquisition of high-quality MR venograms and can be employed for the display of the deep and superficial venous system of upper and lower extremity including pelvic and central thoracic veins. This article describes the employed technique and provides a comprehensive image-based overview of the various indications for direct-infusion 3D MR venography such as post-/thrombotic changes, varicosities, and assessment of the greater saphenous vein prior to bypass surgery. Received: 17 March 2000 Revised: 16 June 2000 Accepted: 19 June 2000     

Deep venous thrombosis evaluation with limited-flip-angle, gradient- refocused MR imaging: preliminary experience

Sixteen patients (17 lower extremities) were prospectively examined with venography and limited-flip-angle, gradient-refocused magnetic resonance (MR) imaging for the presence or absence of deep venous thrombosis. Thrombosed vessels showed decreased-to-absent signal intensity, while patent vessels had high signal intensity. In 16 of 17 extremities, MR images allowed accurate detection and localization of the thrombi found with venography. In the remaining extremity, MR imaging allowed correct identification of thrombus in the iliac and femoral veins but incorrectly demonstrated clot in the calf and popliteal veins. MR imaging with limited-flip-angle, gradient-refocused pulse sequences appears to be a sensitive, noninvasive means of detecting deep venous thrombosis.     

Venous compression syndromes: clinical features,imaging findings and management

Extrinsic venous compression is caused by compression of the veins in tight anatomic spaces by adjacent structures, and is seen in a number of locations. Venous compression syndromes, including Paget–Schroetter syndrome, Nutcracker syndrome, May–Thurner syndrome and popliteal venous compression will be discussed. These syndromes are usually seen in young, otherwise healthy individuals, and can lead to significant overall morbidity. Aside from clinical findings and physical examination, diagnosis can be made with ultrasound, CT, or MR conventional venography. Symptoms and haemodynamic significance of the compression determine the ideal treatment method.Extrinsic venous compression occurs by adjacent arterial, ligamentous, muscular or osseous structures in tight anatomic spaces [1]. Despite its relative infrequency, venous compression is most commonly seen in otherwise healthy and young individuals and may cause significant haemodynamic alterations that may lead to clinical symptoms and significant associated morbidity. Venous compression usually becomes clinically significant when there is a change in the flow direction or increased venous pressure, which lead to the formation of venous collaterals, varicosities and/or chronic venous insufficiency [2]. Repetitive endothelial injury at the site of extrinsic compression predisposes to acute or chronic venous thrombosis, which in turn may aggravate venous hypertension downstream [2].Diagnosis of venous compression is based on a combination of clinical and imaging features. A wide range of signs and symptoms may be seen, including pain, swelling, venous thrombosis, varicosities and haematuria [1,2]. External venous compression incidentally demonstrated by imaging may not be of clinical significance on its own; therefore, imaging should be used for confirmation of the cause of the symptoms. Ultrasound with Doppler, contrast-enhanced CT, CT venography (CTV), contrast-enhanced MRI and MR venography (MRV) are helpful in the diagnosis of venous compression syndromes [3].Ultrasound has been utilised to identify deep venous thrombosis (DVT) within the vein affected by the compression and allows for evaluation of the flow direction and dynamic examinations of the area of interest. Although MRV is more expensive than CTV, there has been an increasing use of MRV since the introduction of blood pool contrast agents and owing to concerns regarding radiation exposure with CTV. Variations in venous haemodynamics from patient to patient make the timing of CTV challenging in obtaining the appropriate venous phase for optimal visualisation of the venous system. MRI provides flow directionality with flow sensitive sequences that could be very valuable in evaluating the haemodynamic significance of the compression. MRV with blood pool contrast agents, such as gadofoveset trisodium, allows for evaluation of the vasculature (arterial and venous) during the steady-state phase. Isotropic high-resolution images can be obtained by allowing multiplanar reformats for better visualisation of compression, characterisation of acute vs chronic clot and venous mapping for procedure planning.Ultimate diagnostic confirmation is obtained by conventional venography, demonstrating pressure gradients across the compressions, flow alteration and/or thrombus within the compressed vein. Several management options unique to the location of venous compression have been described, including conservative, endovascular and surgical treatment options.In this review, we discuss the underlying anatomy, pathophysiology, diagnostic methods and management options of various venous compression syndromes namely May–Thurner syndrome (MTS), Paget–Schroetter syndrome (PSS), Nutcraker syndrome (NCS) and popliteal venous compression (PVC).     

Deep venous thrombosis in pregnancy: noninvasive diagnosis

In pregnant patients, venous thrombosis usually affects the left-side iliofemoral deep vein. Vascular ultrasound (US) offers distinct advantages in confirming the clinical suspicion of disease or suggesting the need for further tests. The authors encountered three consecutive cases of antepartum proximal vein thrombosis during a 6-month period (0.6 case per 1,000 deliveries). Lack of venous flow accentuation and lack of diameter change at the common femoral vein during the Valsalva maneuver are indications for iliac venography and suggest the diagnosis of iliac vein thrombosis. In distal iliac and proximal femoral vein thrombosis, noncompressibility of the vein and the presence of echogenic material within are indicative of acute thrombus.     

Intravascular ultrasound in the diagnosis and treatment of iliac vein compression (May-Thurner) syndrome

Intravascular ultrasound (IVUS) imaging and venography of the left common femoral and iliac veins were performed in 16 patients. The studies were evaluated for the anatomic cause of obstruction and how IVUS influenced endovascular management. IVUS demonstrated the cause of vessel compression in all 16 patients. Other findings, such as associated thrombus and guide wire localization within the residual vessel lumen, can modify the approach to intervention in as many as 50% of patients. IVUS is a useful adjunct in the diagnosis and endovascular management of iliac vein compression syndrome.     

64排螺旋CT静脉造影诊断下肢静脉血栓性病变

目的:探讨64排螺旋CT静脉造影(CTV)诊断下肢静脉血栓性病变的临床价值。材料和方法:下肢多层螺旋CT静脉造影(MSCTV)检查12例,同期均做下肢静脉Dopp ler超声(US)检查;其中1例同时进行了肺动脉CT血管造影,并于延迟2m in时行间接法下肢静脉造影检查。病例均采用5mm层厚和层间距行踝关节至髂骨上缘水平的增强CT扫描,并获得原始图像,图像经1.25mm层厚和50%的重叠处理后传送至工作站进行图像后处理。结果:64排螺旋CTV诊断下肢深静脉血栓(DVT)11例,诊断下肢慢性静脉功能不全1例,同时合并肺栓塞1例。以US作对照,64排螺旋CTV显示股静脉和腘静脉血栓的敏感性为100%,特异性98.6%。MSCTV上DVT表现为静脉腔内不规则低密度充盈缺损,慢性静脉功能不全表现为深静脉边缘不规则且于延迟2m in扫描见其远端引流静脉区造影剂点状残留。结论:64排螺旋CTV在显示股腘静脉血栓与US具有同等价值,MSCTV可作为下肢静脉血栓性病变诊断的常规检查方法。     

Deep venous thrombosis: diagnosis by using venous enhanced subtracted peak arterial MR venography versus conventional venography

PURPOSE: To assess diagnostic accuracy and interobserver variability at venous enhanced subtracted peak arterial (VESPA) magnetic resonance (MR) venography compared with those at conventional venography for the diagnosis of femoral and iliac deep venous thrombosis (DVT). MATERIALS AND METHODS: A single anteroposterior maximum intensity projection (MIP) venogram of the femoral and iliac veins was constructed by using VESPA MR venography in 55 symptomatic patients suspected of having lower limb DVT. All patients also underwent conventional venography, results of which were used as the standard of reference. VESPA MR venograms were interpreted by two independent reviewers (reviewers A and B) who were unaware of other results. Sensitivity and specificity of VESPA MR venography for the diagnosis of thrombus in the femoral and iliac veins were calculated. Interobserver variability was calculated for these observations by using weighted kappa with equally spaced weights for positive, nondiagnostic, and negative studies. Nondiagnostic studies were reinterpreted separately by reviewer A on the basis of source data. RESULTS: Sensitivity of VESPA MR venography for the femoral veins (20 of 20) and iliac veins (seven of seven) was 100% for both reviewers. Specificity was 100% (39 of 39 for reviewer A, 40 of 40 for reviewer B) for the iliac veins and 97% (31 of 32) for the femoral veins for both reviewers. Segments in which the VESPA MR venograms were nondiagnostic were excluded from this analysis. Interobserver variability as calculated by using weighted kappa for positive, negative, and nondiagnostic studies was 0.85 for femoral veins and 0.97 for iliac veins. Interpretation of the source data led to correct diagnosis in six of six cases in which the VESPA MR venograms were nondiagnostic. CONCLUSION: VESPA MR venography yielded MIP venograms that were highly accurate for the diagnosis of DVT in femoral and iliac veins. Interpretation of the studies was also highly reproducible.     

Deep venous thrombosis of extremities: role of MR imaging in the diagnosis

Current noninvasive imaging techniques for diagnosis of deep venous thrombosis (DVT) of extremities are limited in their ability to demonstrate central vein involvement and to distinguish acute from chronic changes. The utility of spin-echo magnetic resonance (MR) imaging for DVT was evaluated in 100 patients suspected of having either upper- (n = 25) or lower-extremity (n = 75) DVT. Ninety-seven patients were imaged successfully. In a subset of 36 patients, prospective comparison of MR imaging with contrast venography revealed a sensitivity of 90%, specificity of 100%, and Kappa level of agreement of .752 (P less than .0001). MR imaging showed more central extent of thrombus than did venography in all five patients with upper-extremity DVT and in 13 of 25 patients (52%) with lower-extremity DVT. Although all patients in the study were evaluated for acute symptoms, 13 of 59 (22%) MR imaging studies positive for DVT demonstrated chronic disease. MR images demonstrated ancillary abnormalities in 18 of 41 (44%) patients who did not have DVT. Thus, MR imaging has a role as the definitive examination when the results of initial screening studies are unsatisfactory, or as a first-line examination if (a) there is suspicion of upper-extremity or pelvic vein thrombosis, (b) there is a history of prior DVT that necessitates distinction of acute from chronic changes, or (c) other tests are unavailable.     

儿童胡桃夹现象的诊断和静脉内支架置入治疗

目的:探讨儿童胡桃夹现象的影像诊断及介入治疗的作用和预后。方法:采用多普勒超声和血管造影及血管内测压对儿童胡桃夹现象进行诊断,并对3例进行了血管内支架治疗及介入治疗后中长期随访观察。结果:CT检查能很好地显示胡桃夹现象的特征。彩色多普勒检查显示左肾静脉最宽径是最窄径的4．20倍(P=0.005),右肾静脉血流峰值是左肾静脉的1．56倍(P=0．006)。血管造影明确显示左肾静脉受压征象,左、右肾静脉压分别为11．66和 7．50 mmHg,压力差为4．11 mmHg,支架置入后左肾静脉压降为8．16 mmHg。术后随访2-3年,患者症状均消失。结论:多普勒超声和血管造影测压均能对胡桃夹现象提供确诊的重要信息,后者更能客观反映胡桃夹现象的病变程度,并可同时进行有效的介入治疗。血管内支架术简便、安全,长期疗效较好,是治疗儿童胡桃夹现象的重要手段。     

Direct contrast-enhanced MR venography in the diagnosis of May-Thurner Syndrome

Visualization of lower extremity veins with MR venography still needs improvement. The latest advancement is direct contrast-enhanced 3D MR venography which is based on display of venous system during direct injection of paramagnetic extracellular contrast agent into pedal veins. We used automated injection of contrast agent with a power injector makings this application simpler and faster, achieved to show the iliac vein compression syndrome and post-thrombotic changes of the left iliac and femoral veins.