Unusual duplication anomaly of the inferior vena cava with normal drainage of the right IVC and hemiazygous continuation of the left IVC.

Duplication of the inferior vena cava (IVC) and other IVC anomalies have been well described in the literature. Although they are often discovered incidentally in patients without symptoms, these anomalies can have significant clinical implications and must be recognized when they occur. In most cases of a duplicated IVC, the right and left iliac veins drain into the right and left IVC, respectively, and the left IVC ends at the level of the left renal vein, subsequently draining into the right IVC. The authors describe a unique case of duplicated IVC with hemiazygous continuation of the left-sided IVC and normal drainage of the right-sided IVC into the right atrium.     

左位下腔静脉的MSCT表现及临床意义

目的 探讨左位下腔静脉的多层螺旋CT(multi-slice spiral CT, MSCT)表现及临床意义。方法 选取腹部MSCT多期增强扫描发现的11例左位下腔静脉患者,结合文献讨论其影像学表现。结果 11例左位下腔静脉MSCT表现为3种类型。Ⅰ型1例（9.09%）,表现为右侧下腔静脉缺失,左右髂总静脉于第5腰椎左前方汇合成下腔静脉主干后,沿腹主动脉左侧垂直上行,沿途先后有右肾静脉和左肾静脉汇入,然后与半奇静脉连接,经上腔静脉汇入右心房。Ⅱ型6例（54.55%）,表现为肾下右侧下腔静脉残余,肾下左位下腔静脉位于腹主动脉左侧,于左肾静脉汇入后从前方跨越腹主动脉向右上走行,与右肾静脉汇合后移行为正常的下腔静脉。Ⅲ型4例（36.36%）,表现为肾下右侧下腔静脉缺失,而左位下腔静脉的起止、位置、走行及属支汇入与Ⅱ型完全相同。结论 左位下腔静脉MSCT表现为3种类型,左位下腔静脉的存在对临床及介入治疗而言具有重要的意义。     

Anatomical observations on the renal veins and inferior vena cava at magnetic resonance angiography

Purpose

To describe the renal vein and inferior vena cava (IVC) anatomy found at abdominal magnetic resonance (MR) angiography.

Methods

Gadolinium-enhanced, three-dimensional, time-of-flight MR angiograms of 150 patients were evaluated for the number and configuration of the renal veins, and the number, configuration, and dimensions of the IVC. Data were analyzed with the Student's ttest.

Results

Retroaortic left renal veins were found in 7% of patients, circumaortic left renal veins in 5%, multiple right renal veins in 8%, and duplicated IVCs in 0.7%. The length of the infrarenal IVC averaged 94 mm in females and 110 mm in males (p<0.00001). The length of the infrarenal IVC in patients with circumaortic and retroaortic left renal veins averaged 76 mm and 46 mm, respectively. The mean maximal caval diameter was 23.5±4 mm. No megacavae (diameter of the mid-IVC > 28 mm) were identified.

Conclusion

Variant renal vein and IVC anatomy can be identified at MR angiography.     

布加综合征血管病变的彩色多普勒超声研究

目的:研究布加综合征患者肝静脉和下腔静脉血管形态病变和血流动力学变化,探讨彩色多普勒超声诊断布加综合征的价值。方法:彩色多普勒超声检查84例布加综合征,均经介入手术或下腔静脉造影证实。重点观察3支肝静脉和下腔静脉的走行、内径、人口、血流方向、血流频谱和流速,并追踪扩张的肝小静脉和肝内外交通支的血流方向。结果:布加综合征患者血管病变复杂多样。本组患者均合并下腔静脉病变,血管病变类型主要为短段性狭窄、短段性闭塞、长段性狭窄、长段性闭塞,左、中、右肝静脉合并受累者分别为62、75、71例(分别占总病例数的73.8%、89.3%和84.5%)。肝内外均见不同类型的交通支,并见代偿扩张的肝右后下静脉和尾叶静脉,均引流血液进入下腔静脉,肝外交通支主要为腹膜后、膈下、脾肾之间交通支以及脐旁静脉重开。结论:彩色多普勒超声可以提供布加综合征血管病变形态和血流动力学的详细资料,对诊断、分型和手术方案制定均有价值,且无创、价廉,应成为布加综合征的首选影像检查技术。     

Imaging of partial right double vena cava with ureter crossing through its split, confirmed at surgery

A complex development process occurs during the embryogenesis of the inferior vena cava (IVC), such as the formation of several anastomoses between three paired embryonic veins, which may result in a wide range of congenital abnormalities of the IVC.We report a case, not described before, of partial double right IVC with a circumcaval ureter crossing through the divide in the IVC.     

Acute thrombosis of the inferior vena cava and hepatic veins in patients with Budd-Chiari syndrome: CT demonstration

We reviewed the CT findings in 17 patients with angiographically proved Budd-Chiari syndrome to determine the ability of CT to show acute thrombosis of the inferior vena cava (IVC) and hepatic veins. In eight patients with membranes (web or band) in the IVC, no thrombus was detected with CT or angiography. In the other nine patients, thrombi in the IVC and/or hepatic veins were seen as intraluminal filling defects that did not change in appearance on precontrast and postcontrast CT scans. Attenuation values of intraluminal filling defects of the IVC ranged from 38 to 42 H in four patients. High-attenuation intraluminal filling defects (60-70 H) of the IVC (five patients) and hepatic veins (one of five patients) were detected. Of these five patients, four had acute symptoms and one had chronic vague symptoms. The underlying disease was a web or band in the IVC and hepatic veins in three patients, invasive hepatocellular carcinoma in one, and injury to the IVC wall during hepatectomy in one. Inferior venacavography showed occlusion of the hepatic segment of the IVC in all five patients. Additional angiograms obtained by injection of contrast medium after a catheter tip was placed in the occluded hepatic IVC showed numerous filling defects suggestive of thrombi of recent onset, which correlated with the high-attenuation thrombi seen on CT scans in two patients. In the remaining three patients, high-attenuation areas in the IVC and hepatic veins also were considered to represent thrombi of recent onset because the attenuation values later decreased to 33-42 H. Spontaneous reduction in diameter of the thrombosed segment of the IVC was observed in four of the five patients. Knowledge of the CT features of acute thrombosis of the IVC and hepatic veins is useful in the early diagnosis of Budd-Chiari syndrome.     

Translumbar high inferior vena cava access placement in patients with thrombosed inferior vena cava filters

Venous access is a dire necessity in some patients such as those with end-stage renal disease or short gut syndrome. The right internal jugular vein is the preferred entry site for tunneled central venous catheters. Alternatively, the left internal jugular is considered next, with the external jugular and subclavian veins being considered later. Catheter-related venous stenosis approaches 40% in certain sites, resulting in loss of access sites. As sites are lost, insertion of functional long-term central venous catheters becomes challenging. Translumbar inferior vena cava (IVC) access created in two patients with limited venous access sites who had thrombosed IVCs containing IVC filters is described. Because of the higher IVC punctures in these cases, procedural planning with cross-sectional imaging is crucial to avoid puncturing the right renal artery as it passes posterior to the IVC.     

Computerized tomography in the follow-up of inferior vena cava filters

CT was employed to evaluate IVC filters in 37 patients; most devices (25) were Greenfield filters. Filters were localized below the renal veins in 26 patients; a suprarenal position was observed in 11 cases. Filter malpositioning was shown by CT in 1 case (filter partially located in the left renal vein); migration of the device into left pulmonary artery was detected in 1 patient. IVC perforation occurred in 11 cases--in 6 of them, the filter penetrated into adjacent structures (duodenum in 2 cases, abdominal aorta in 2, liver in 1, and right kidney in 1 patient). IVC thrombosis was seen in 16 patients; complete caval obstruction developed in 2 cases two or more years after filter positioning. IVC perforation caused by a filter is a frequent complication (30% of our series), but in most cases it is asymptomatic and has no significant clinical relevance; surgical removal of the filter had to be performed in 3 cases only. CT scanning is a valuable adjunct to plain abdominal radiography in the follow-up of IVC devices, when a complication (especially IVC perforation) is suspected.     

Spectrum of congenital anomalies of the inferior vena cava: cross-sectional imaging findings.

Congenital anomalies of the inferior vena cava (IVC) and its tributaries have become more commonly recognized in asymptomatic patients. The embryogenesis of the IVC is a complex process involving the formation of several anastomoses between three paired embryonic veins. The result is numerous variations in the basic venous plan of the abdomen and pelvis. A left IVC typically ends at the left renal vein, which crosses anterior to the aorta to form a normal right-sided prerenal IVC. In double IVC, the left IVC typically ends at the left renal vein, which crosses anterior to the aorta to join the right IVC. In azygos continuation of the IVC, the prerenal IVC passes posterior to the diaphragmatic crura to enter the thorax as the azygos vein. In circumaortic left renal vein, one left renal vein crosses anterior to the aorta and another crosses posterior to the aorta. In retroaortic left renal vein, the left renal vein passes posterior to the aorta. In circumcaval ureter, the proximal ureter courses posterior to the IVC. Other anomalies include absence of the infrarenal IVC or the entire IVC. These anomalies can have significant clinical implications. Awareness of these anomalies is necessary to avoid diagnostic pitfalls.     

血管平滑肌瘤病影像学评估

目的 探讨血管平滑肌瘤病的影像学表现.资料与方法 分析6例手术病理证实的血管平滑肌瘤病的影像学表现.结果 5例肿瘤起自子宫端,1例局限在下腔静脉内.3例经下腔静脉延伸到右心房,其中1例经右心房到右心室.6例CT显示下腔静脉和/或卵巢静脉扩张,1例左肾静脉扩张.增强后表现为血管内和右心腔内充盈缺损,呈"血管内血管"征;肿瘤自身可呈不均匀强化.2例MRI显示腔静脉扩张,流空效应消失.结论 CT和MRI能提示血管平滑肌瘤病.     

Transjugular liver biopsy via the left internal jugular vein

PURPOSE: To retrospectively review the indications and outcomes of transjugular liver biopsy (TJLB) with the left internal jugular vein (IJV) approach. MATERIALS AND METHODS: A retrospective review of all TJLBs performed at one institution was performed. From August 1995 to October 2004, 293 liver biopsies were performed. Nineteen of the 293 procedures (6.5%) were performed from the left IJV in 17 patients. There were 11 men and six women aged 36-59 years (mean, 49.3 years). All patients were suspected of having diffuse hepatic parenchymal disease and had contraindications to conventional percutaneous liver biopsy. The stiff metal biopsy cannula was advanced across the mediastinum and through the heart over a stiff guide wire. Biopsy was performed from the right hepatic vein in 15 procedures, the middle hepatic vein in two, and the intrahepatic IVC in two. RESULTS: The indications for using the left IJV approach were nonusable right IJV in 12 procedures, difficult previous catheterization of the hepatic veins from the right IJV due to distorted hepatic anatomy in six procedures, and the operator's predilection for this approach in one procedure (the patient had previously undergone liver transplantation). All biopsies were successful, with diagnostic tissue obtained in 100% of cases. Two patients had chest pain during the procedure associated with placement of the rigid cannula through the mediastinal veins. One patient had a vaso-vagal episode that necessitated the use of intravenous atropine but subsequently underwent successful biopsy. All episodes of chest pain resolved after the cannula was removed. There were no recorded hemorrhagic or cardiac complications. CONCLUSION: TJLB can be safely and repeatedly performed from the left IJV when the right IJV is not available or the hepatic anatomy prevents catheterization of the hepatic veins from the right IJV.     

Percutaneous insertion of the Kimray-Greenfield filter: technical considerations and problems

Kimray-Greenfield filters were inserted percutaneously into the inferior vena cava (IVC) in 57 patients. Thirty-six were placed from the right femoral vein, 14 from the left femoral vein, and seven from the right internal jugular vein. There were no deaths or major complications and only six minor complications. Inferior vena cavography was done before filter insertion in all cases. Cavography is vital to determine feasibility of filter insertion, route of insertion, and filter location; pertinent findings include caval size, presence or absence of clot in the IVC or iliac veins, and position of the renal veins. The guide wire provided with the standard filter introduction set has a tendency to catch on the filter as the wire is withdrawn. A stiff wire with a straight, tapered, floppy tip was substituted. The femoral approach is preferred when it is feasible. Though there was only one known occurrence of femoral vein thrombosis at the filter insertion site, other cases may have occurred and may not have been detected. If the frequency of this complication proves to be significant, the preferred route for filter insertion may have to be reconsidered.     

Concomitant pulmonary arteriovenous and inferior vena cava malformations. A case report

A case of pulmonary arterio-venous malformation (AVM) presenting with dyspnoea diagnosed by computer tomography (CT) and pulmonary angiography is reported. Venous anomalies in the form of agenesis of the iliac veins and the inferior vena cava (IVC), were discovered through femoral venograms performed after technical difficulties were encountered at pulmonary angiography performed via the femoral route. These venous anomalies co-existed with normal but dilated azygos and hemiazygos systems, and with the azygos appearing as a right hilar mass lesion which showed the "candy cane sign" on the lateral view on venography. A dilated varix at the confluence of the right renal vein and the IVC collaterals was also noted. This association of a pulmonary AVM and IVC agenesis has not been previously reported in the literature. The embryogenesis of the inferior vena cava and the azygos system is presented in an attempt to explain the rare association of these anomalies. The various techniques of diagnosing the disease entities, especially by CT, are discussed. The rare co-existence of pulmonary AVM and the absence of the IVC is emphasized.     

Transhepatic Guidance of Translumbar Hemodialysis Catheter Placement in the Setting of Chronic Infrarenal IVC Occlusion

When patients with end-stage renal disease have exhausted both conventional and unconventional venous access options, creative solutions must be sought for hemodialysis catheter placement in order to ensure survival. This case describes a patient in urgent need of a dialysis catheter despite total occlusion of the jugular, subclavian, and femoral veins. Occlusion of the inferior vena cava (IVC) and right renal vein resulted in failed attempts at translumbar catheter placement. A gooseneck snare was temporarily advanced through the liver to the IVC for use as a fluoroscopic target to facilitate successful single-puncture, translumbar catheterization.     

Radionuclide venography as a clue to the diagnosis of Budd-Chiari syndrome

A patient was examined with radionuclide venography (RVG) to investigate unilateral leg oedema which might be due to deep vein thrombosis. RVG with Tc-99m MAA demonstrated no findings to suggest deep vein thrombosis of the right leg. However, collateral flow derived from the left common iliac vein and truncated inferior vena cava (IVC) were revealed. Contrast venography confirmed the obstruction of IVC and collateral flow from the left common iliac vein to the left ascending lumbar vein. It also showed the obstruction of hepatic veins and the patient was finally diagnosed as Budd-Chiari syndrome. Although unilateral leg oedema is an atypical symptom in Budd-Chiari syndrome, the findings on RVG led us to conduct further imaging studies to reach the diagnosis.     

Symptomatic interrupted inferior vena cava: report of a case presenting with haematochezia

Interrupted inferior vena cava (IVC) is a rare developmental defect. IVC interruption is usually accompanied with azygos and hemiazygos continuation, and is asymptomatic. Here, we report the imaging findings of a patient with an interrupted IVC with diffuse collaterals between the infrarenal IVC and large renal veins, left gonadal, and perirectal haemorrhoidal-portal collateral veins with associated haematochezia. Depending on the haemodynamic changes, interrupted IVC may cause possible different clinical findings as presented here.     

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.     

Scimitar syndrome versus meandering pulmonary vein: evaluation with three-dimensional computed tomography

We report two cases of abnormal configuration of the pulmonary venous system of the right lung evaluated with the use of three-dimensional spiral computed tomography (3D-CT). In the first case, an unusual form of scimitar syndrome was detected, consisting of two scimitar veins uniting into a common trunk immediately before their confluence into the inferior vena cava (IVC). The second case concerns a meandering pulmonary vein that followed a circuitous course through the right lung and came in close proximity to the IVC, before draining the entire right lung to the left atrium. In both cases, 3D-CT enabled a non-invasive, detailed anatomic evaluation of the right pulmonary vascular bed.     

下腔静脉畸形的64层螺旋CT表现

目的 探讨64层螺旋CT下腔静脉畸形的影像表现.方法 回顾性分析6986例受检者的腹部64层螺旋CT增强扫描资料,共发现25例下腔静脉先天畸形.分析下腔静脉畸形的影像表现.结果 25例下腔静脉畸形中包括左下腔静脉6例,CT表现为肾下段腹主动脉左侧上行的下腔静脉.双下腔静脉10例,CT表现为肾下段腹主动脉两侧上行的下腔静脉.左肾静脉畸形5例,CT增强扫描横断面显示腹主动脉后和环主动脉走行的左肾静脉.肝下段下腔静脉中断伴奇静脉延续2例,胸腹部CT增强扫描显示肝段至肾上段下腔静脉缺如,肾段下腔静脉由奇静脉延续回流人上腔静脉,而肝静脉直接回流右心房.腔静脉血管造影见对比剂经增粗的奇静脉和半奇静脉通过上腔静脉回流右心房.肝下段下腔静脉中断伴门静脉延续1例,增强CT显示下腔静脉直接与门静脉在肝门部连接,肝门部门静脉呈瘤样扩张.左下腔静脉伴半奇静脉延续1例,增强CT可见左下腔静脉与半奇静脉连接,上行汇入奇静脉.结论 64层螺旋CT可清晰显示下腔静脉及其属支的畸形,可成为下腔静脉畸形的重要诊断方法.     

Adjunctive Inferior Vena Cava Filter Placement for Acute Pulmonary Embolism

Inferior vena cava (IVC) filters are sometimes placed as an adjunct to full anticoagulation in patients with significant pulmonary embolism (PE). We aimed to determine the prevalence of adjunctive IVC filter placement in individuals diagnosed with PE, as well as the effect of adjunctive filter placement on mortality in patients with right heart strain associated with PE. This was a retrospective study of patients with acute PE treated with full anticoagulation admitted to a single academic medical center. Information abstracted from patient charts included presence or absence of right heart strain and of deep-vein thrombosis, and whether or not an IVC filter was placed. The endpoint was in-hospital mortality. Over 2.75 years, we found that 248 patients were diagnosed with acute PE, with an in-hospital mortality rate of 4.4%. The prevalence of adjunctive IVC filter placement was 13.3% (33 of 248), and the prevalence of documented right heart strain was 27.0% (67 of 248). In-hospital mortality was 10.2% in the non-filter-treated group (5 of 49), whereas there were no deaths in the filter-treated group (0 of 18); however, the difference was not statistically significant (P = 0.37). Both the presence of deep-vein thrombosis and of right heart strain increased the likelihood that an adjunctive IVC filter was placed (P < 0.0001 and P < 0.001, respectively). At our institution, patients were treated with IVC filters in addition to anticoagulation in 13.3% of cases of acute PE. Prospective studies or large clinical registries should be conducted to clarify whether this practice improves outcomes.