Imaging the inferior vena cava: a road less traveled

It's a long way to the top! Congenital venous anomalies and left isomerism limiting atrial fibrillation transcatheter ablation

BACKGROUND

Atrial fibrillation is the most common sustained cardiac arrhythmia in adults and it is associated with a high burden of mortality and morbidity worldwide. Catheter ablation is increasingly used to improve symptoms and prognosis in selected patients. Lower limb venous access with subsequent transseptal approach to the left atrium is the standard procedure for atrial fibrillation catheter ablation.

CASE PRESENTATION

We report an unusual case of complex venous anomaly with a left-sided inferior vena cava with hemiazygos continuation to a persistent left superior vena cava draining in an enlarged coronary sinus in a patient with persistent atrial fibrillation scheduled for transcatheter ablation.

DISCUSSION

Lower limb venous anomalies may limit a standard transseptal approach to the left atrium thus precluding an effective catheter ablation procedure for atrial fibrillation. Alternative interventions, such as unconventional percutaneous access, thoracoscopic approach and "ablate and pace" procedures, may be necessary in patients with symptomatic atrial fibrillation and complex venous anomalies.

Intrahepatic and anterior course of the inferior vena cava: CT image and 3D reconstruction of a rare anatomical variation

The widespread use of computed tomography (CT) for diagnosing and screening abdominal conditions often reveals rare, asymptomatic anomalies. There is a wide range of documented congenital variations in the anatomy of the inferior vena cava (IVC) and hepatic veins. In this report, we detail an exceptionally unusual variant of the IVC that follows a frontward and intraliver course, terminating at the anterior section of the right atrium. To gain a deeper insight into this anomaly, we employed 3D reconstruction techniques using the software Slicer and Blender.

Para-aortic lymphadenectomy in endometrial cancer patients with left-sided inferior vena cava: A case report and literature review

OBJECTIVE

The incidence of left-sided inferior vena cava (IVC) is extremely low. However, without a preoperative diagnosis of left-sided IVC, the risk of intraoperative vascular injury during para-aortic lymph node (PAN) lymphadenectomy is high.

CASE REPORT

Herein, we present two cases in which left-sided IVCs were diagnosed using preoperative imaging. PAN lymphadenectomies were safely performed in these patients with endometrial cancer. In the first case, the left-sided IVC crossed the abdominal aorta after the left renal and gonadal veins had drained into it and joined the right renal vein. In the second case, the left-sided IVC crossed the abdominal aorta after the left renal and gonadal veins flowed into it and the ascending lumbar vein flowed into the right side.

CONCLUSION

These cases demonstrate that even in the presence of vascular malformations, PAN lymphadenectomy can be performed safely by employing preoperative anatomical imaging analysis and judicious intraoperative surgical maneuvers to avoid vascular injury.

Case Report: Imaging features of a new type double inferior vena cava malformation and review

Background

Double inferior vena cava (DIVC) is a rare vascular malformation. With advances in radiological techniques and diagnosis, more and more types of DIVC were identified and diagnosed. Recognition of the variety of DIVC seen on imaging is essential for subsequent venous interventions.

Case presentation

A 77-year-old man presented with low back pain with left lower limb pain for 1 month. Scattered petechiae above the skin surface on the left lower leg, especially on the extensor surface, with flaking and mild tingling of the skin, were noted 3 weeks ago. Ultrasound revealed deep vein thrombosis (DVT) in the left lower limb. Computed tomography pulmonary angiography (CTPA) suggested no significant thrombus in the pulmonary artery. Computed tomography venography (CTV) of bilateral lower limbs showed that iliac vein compression syndrome with formation of deep and superficial venous traffic branches in bilateral lower limbs, predominantly on the left side. CTV of the inferior vena cava (IVC) suggested that the left common iliac vein crossed the common iliac artery bifurcation from dorsal to ventral and continued to travel cranially as a ventral vessel, and connected with the ventral IVC anterior to the right common iliac artery. The right common iliac vein extended cephalad as a dorsal vessel, which was narrowed at the level of 4th lumbar vertebra by compression of the hyperplastic bone and the osteophyte. The patient was discharged after right and left common iliac vein angiography and balloon dilation of bilateral common iliac vein.

Conclusion

The formation of both ventrally and dorsally aligned DIVC is rarer. It should be clarified the effects of DIVC on DVT formation, and the importance of imaging for preoperative planning.

Imaging of inferior vena cava normal variants, anomalies and pathologies, Part 1: Congenital

The embryology of the inferior vena cava (IVC) is complex, involving the sequential appearance and regression of multiple segments that ultimately form the IVC. Any alteration in this process during embryogenesis can result in congenital anomalies of the IVC. This study aimed to recognise common as well as rare anomalies of the IVC and associated veins, and their clinical implications. The anomalies tend to have diverse appearances based on the timing and segments involved. The development of the IVC is intertwined with the development of other veins like the renal vein, azygos vein and portal vein, and these veins may also be anomalous. Additionally, IVC anomalies are associated with various other congenital anomalies including cardiac anomalies, the recognition of which may be important for patient care. The IVC tends to have multiple normal variants and anomalies because of a complex process involving multiple segments contributing to the adult IVC. Knowledge of these variants is crucial for preoperative planning of procedures.

Contribution

This study would help in understanding the embryogenesis of the IVC and correlation with the imaging appearances and the clinical implications of each of these common as well as rare types of congenital anomalies.

Endovascular reconstruction of the inferior vena cava in a patient presenting with deep venous thrombosis with concomitant inferior vena cava hypoplasia and aneurysmal dilatation of the iliac veins

INTRODUCTION

Congenital malformations of the inferior vena cava are rare and remain an under recognised cause of spontaneous deep venous thrombosis (DVT). The purpose of this case report is to highlight the rare occurrence of a concomitant iliac vein aneurysm and the feasibility of endovascular reconstruction in the presence of extensive iliocaval thrombus burden, especially in cases where other treatment modalities have been unsuccessful.

REPORT

This is the report of a 25-year-old male who presented with acute onset left lower limb pain/swelling secondary to extensive iliocaval DVT. This was due to multiple abnormalities of the venous system including hypoplasia of the IVC with aneurysmal dilatation of the iliac veins. He failed an initial management strategy of anticoagulation and thrombolysis but subsequently underwent endovascular reconstruction of the iliocaval system via venoplasty and stenting. Complete symptom resolution and venous patency, including resolution of venous aneurysmal disease, were maintained at twelve-month follow-up.

DISCUSSION

Reduction of the iliac vein diameter so early after successful reconstruction suggests that the iliac venous aneurysm was secondary to significant venous hypertension, and that if the obstruction causing it is treated, the vein can return to a normal vessel diameter.

A Rare Case of Renal Cell Carcinoma With Inferior Vena Cava Invasion: A Life-Threatening Complication

Renal cell carcinoma (RCC) arises from the renal tubular epithelial cells and comprises a group of heterogenous renal tumors. Renal tumors can metastasize to involve almost any body organ, the common sites being the lung, liver, bone, brain, adrenal gland, head, neck, and rarely, inferior vena cava (IVC), leading to lethal outcomes. We present a case of RCC with IVC invasion in a patient who presented with right-sided flank pain and gross hematuria. His routine biochemical and hematological parameters were unremarkable, and an abdominal examination revealed a complex renal mass with mild hydronephrosis. The patient underwent contrast-enhanced magnetic resonance angiography with venography, which showed a right renal upper polar mass lesion extending into the right vein obliterating it up to its junction with the IVC. Integrating examination and imaging findings were suggestive of right renal RCC. Our case highlights the importance of standard preoperative MRI imaging to assess IVC invasion and its morphologic features including vessel breach or complete occlusion of the IVC.

Evaluation of Normal Inferior Vena Cava Diameters in the Indian Adult Population by Computed Tomography

Background The imaging evaluation of inferior vena cava (IVC) diameters is essential for the estimation of vena caval pathologies and can also detect early hypovolemic shock. There are very few studies on normal IVC diameters on CT scan done in foreign countries, and none done in the Indian population. Aims The goal of this research is to assess the normal IVC diameter in the Indian adult population by performing a CT scan of the abdomen. Material and methods In this study, CT scans of 200 individuals (aged 19-83) without any circulatory and vascular disorders were analyzed retrospectively. The anteroposterior (AP) and transverse diameters of the IVC were measured at the level of the renal vein and at the level 2 cm proximal to insertion in the heart (usual area of measurement on ultrasonography). Results The study discovered normal adult mean AP and transverse dimensions of the IVC at the level of the renal vein as 16.3 ± 2.9 mm and 25.8 ± 3.5 mm, respectively, and 16.9 + 3.2 mm and 26.2 + 3.6 mm at the level 2 cm proximal to its insertion in the right atrium. Conclusions In this study, the normal morphometric dimensions of the IVC in the Indian adult population were established. The diameters of the IVC and the age of the participants in our study had no statistically significant correlation, however, the IVC changes its cross-sectional area and diameter due to changes in venous pressure and blood pressure and hence is a highly compliant vessel. The results of the study will be used as baseline data for the assessment of IVC disorders.

An usual case of bilateral deep venous thrombosis with associated pulmonary embolus

Congenital absence of the inferior vena cava (IVC) triggers collateral vessel growth to drain the peripheries and abdominal organs. This causes venous stasis and increases the risk of deep vein thrombosis (DVT) and pulmonary embolism. Typically, patients with absent IVCs present before 30 years of age, with bilateral DVT symptoms triggered by intense exercise. The abnormality can remain undetected as computed tomography imaging is not usually performed. Due to the increased risk of clotting, these patients should be on life-long anticoagulation. Raising clinical awareness of this condition, to ensure appropriate investigations and treatment, is important.

Evaluation of outcome from endovascular therapy for Budd-Chiari syndrome: a systematic review and meta-analysis

This study was performed to evaluate the outcome of endovascular intervention therapy for Budd-Chiari syndrome (BCS) and compare recanalization, transjugular intrahepatic portosystemic shunt (TIPS)/direct intrahepatic portosystemic shunt (DIPS), and combined procedure treatment. For the meta-analysis, 71 studies were identified by searching four databases. The individual studies’ samples were used to calculate a confidence interval (CI 95%), and data were pooled using a fixed-effect model and random effect model. The pooled measure and an equal-weighted average rate were calculated in all participant studies. Heterogeneity between the studies was assessed with I², and T² tests, and publication bias was estimated using Egger’s regression test. A total of 4,407 BCS patients had undergone an endovascular intervention procedure. The pooled results were 98.9% (95% CI 97.8‒98.9%) for a technical success operation, and 96.9% (95% CI 94.9‒98.9%) for a clinical success operation. The re-intervention rate after the initial intervention procedure was 18.9% (95% CI 14.7‒22.9%), and the survival rates at 1 and 5 years after the initial intervention procedure were 98.9% (95% CI 96.8‒98.9%) and 94.9% (95% CI 92.9‒96.9%), respectively. Patients receiving recanalization treatment (98%) had a better prognosis than those with a combined procedure (95.6%) and TIPS/DIPS treatment (94.5%). The systematic review and meta-analysis further solidify the role of endovascular intervention treatment in BCS as safe and effective. It maintains high technical and clinical success and long-term survival rates. The recanalization treatment had a better prognosis and outcome than the combined procedures and TIPS/DIPS treatment.

Computed tomographic appearance of transcaval ureter in two dogs and three cats: A novel CVC congenital malformation

Transcaval ureter is a rarely reported human congenital malformation of the prerenal segment of the inferior vena cava (IVC) not yet reported in veterinary medicine. The objective of this multicenter retrospective case series study was to describe the computed tomography (CT) features of transcaval ureters in dogs and cats. Patients referring to pre- and post-contrast CT exams of the abdomen and presenting this abnormality were retrospectively included. Multiple qualitative features were described for each ureteral abnormality detected. Three cats and two dogs with transcaval ureter were identified consisting of a segmental duplication of the CVC at the prerenal level creating a vascular ring through which the ureter extended, identified as a double-barrel gun sign. The malformation was divided into two types according to the symmetry of the caval branches and location in relation to the aorta, namely, type I symmetrical branches and right-lateral to the aorta, and type II asymmetrically branches and right-dorsal to the aorta. In one case, the malformation was associated with hydroureter and mild pyelectasis. In three cases, the anomaly was incidental and, in the remaining two cases, the clinical significance was uncertain. This is the first study describing the presence of transcaval ureter in dogs and cats. CT was a suitable method for the diagnosis of transcaval and a focal double-barrel gun sign of the CVC is proposed as the hallmark feature of this anomaly. The clinical relevance of this congenital vascular malformation is unclear and needs to be further investigated.

Morphometric analysis of the inferior vena cava and its clinical correlations using abdomino-pelvic computed tomography: Series from a Jordanian population

Introduction and importance

This study aimed to determine the impact of DM, HTN and age on IVC dimensions as measured by CT scan relevant to guide interventions in a Jordanian population.

Presentation of cases

Two hundred patients were selected from those referred to the Radiology Department, Jordan University Hospital, Amman, Jordan for clinical evaluation. Patients were divided into three age subgroups. Age, sex, and comorbidities such as DM and HTN were identified and saved for later use. All dimensions of the IVC were measured using an abdomino-pelvic CT scanner.

Clinical discussion

A full morphometric analysis of the IVC would provide a better understanding of the dynamicity of the IVC in relation to its blood flow. Our results revealed that the length of the IVC was significantly shorter with age (P = 0.003). DM significantly affected the length of the IVC (P = 0.044). Hypertension also significantly affected the length of the IVC (P = 0.031), but it did not significantly affect the anterio-posterior or the transverse diameters of the IVC.

Conclusion

The length of the IVC was significantly shorter with age, DM and hypertension. Morphometric measures of the IVC are of great clinical importance as they may assist in medical or surgical intervention and follow-up.

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Determining the main dimensions of IVC is clinically important.

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This study revealed significant variability in IVC dimensions in relation to age.

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Diabetes and hypertension are important in changing the dimensions of IVC.

Rare congenital abnormality resulting in spontaneous bilateral deep venous thrombosis and pulmonary emboli in a young healthy man

This report describes a unique case of a healthy man in his 30s, who presented with progressive unilateral leg swelling with no common risk factors identified. Two days prior to the swelling he had developed significant abdominal pain following a treadmill exercise session. Ultrasound imaging revealed extensive deep vein thrombosis involving bilateral ileo-femoral venous systems, extending up the inferior vena cava (IVC). Further investigation using a CT venogram revealed the rare congenital anomaly of hypoplasia of the renal IVC. Successful treatment involved 48 hours of an intravenous unfractionated heparin infusion, followed by lifelong anticoagulation.

An unusual case of dilated coronary sinus: case report and clinical implications

Background 

The presence of a dilated coronary sinus (CS) assessed by transthoracic echocardiography (TTE) is highly suggestive of inferior or superior vena cava (SVC) anomalies, in the absence of a shunt. The most frequent finding is the persistence of a left superior vena cava (LSVC): well-known feature to electrophysiologists. Abnormal inferior vena cava (IVC) drainage is another cause of CS dilatation.

Case summary 

An 83-year-old woman presented with heart failure symptoms, atrial fibrillation with rapid ventricular rate, and a dilated CS assessed by TTE. Atrioventricular (AV) node ablation was considered given the poor efficacy of a rate control strategy. Cardiac computed tomography (CT) revealed a double SVC with an LSVC draining directly into the dilated CS. Single-lead pacemaker implantation was performed using a right-sided vascular access with no technical difficulties. An aborted AV node ablation procedure was due to the impossibility of getting to the right atrium. Fluoroscopy and CT imaging at second look analysis confirmed the diagnosis of an abnormal IVC with an agenesia of its supra-hepatic segment directly drained into the CS.

Discussion 

Our clinical case illustrates an unusual and rare double venous abnormality: both LSVC and IVC directly drained into the CS and were responsible for its massive dilatation.

Current update on IVC leiomyosarcoma

Primary leiomyosarcoma of the inferior vena cava (IVC) is a rare soft tissue sarcoma associated with poor prognosis. Patients are often asymptomatic or present with nonspecific abdominal symptoms, which delays initial diagnosis and contributes to poor oncologic outcome. Key imaging modalities include ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI). Characteristic imaging features include imperceptible caval lumen, dilation of the IVC, heterogeneous enhancement of the tumor, and development of extensive collateral circulation. Surgical resection is the mainstay of treatment, while chemotherapy and/or radiation may serve as therapy adjuncts. This article reviews the pathology, clinical findings, imaging features and management of IVC leiomyosarcoma.

Anomalies of Inferior Vena Cava: Implications and Considerations in Retroperitoneal Surgical Procedures

Anomalies of the inferior vena cava pose a great challenge to surgeons. Although uncommon, these congenital vascular malformations may have significant surgical implications. Awareness of their presence is essential to avoid inadvertent injury and major bleeding during retroperitoneal procedures. An accurate preoperative diagnosis and detailed planning play a crucial role to obtain successful outcomes when confronted with them. Several surgical techniques have been recommended to protect these anomalous venous structures. The aim of this review is to contribute to the knowledge of the most common types of anomalies of inferior vena cava encountered during retroperitoneal procedures. With this purpose, a summary of their anatomy, embryology, incidence, diagnosis and intra-operative management is presented.

Anomalous Circumrenal Inferior Vena Cava Associated With Horseshoe Kidney

A 69-year-old male presented with periumbilical pain radiating across his abdomen, with associated nausea and emesis. CT imaging of his abdomen and pelvis revealed calculi in the right and left ureterovesical junctions with hydroureteronephrosis bilaterally. Furthermore, the imaging revealed that the patient had a horseshoe kidney with an associated anomalous inferior vena cava (IVC) that split superiorly to the horseshoe kidney at the L1 level and rejoined inferior to the horseshoe kidney at the L5 level. The IVC took on a "circumrenal" course, as it traversed the right kidney with an anterior and posterior portion. Furthermore, the patient's right ureter was compressed between the anterior portion of the IVC and the right kidney. We hypothesize that the development of the horseshoe kidney around the 7 to 8th week of gestation created a path of resistance for the forming of IVC around the same time. While surgical correction is not warranted, recognition of this circumrenal IVC variant could have major implications for planning of procedures, such as IVC filter placement.

The inferior vena cava: anatomical variants and acquired pathologies

The inferior vena cava (IVC) is the largest vein in the body, draining blood from the abdomen, pelvis and lower extremities. This pictorial review summarises normal anatomy and embryological development of the IVC. In addition, we highlight a wide range of anatomical variants, acquired pathologies and a common pitfall in imaging of the IVC. This information is essential for clinical decision making and to reduce misdiagnosis.

Imaging in traumatic injury to the inferior vena cava

Inferior vena cava (IVC) injury is a rare but serious consequence of trauma. It presents with high scores on trauma assessment scales and is often life threatening. Factors that contribute to poor survival include delay and difficulty in diagnosis due to non-specific clinical features. As it is a relatively rare entity, imaging in IVC injury is not well described in the literature. As radiologists, it is vital that features of potential IVC injury are recognised promptly and findings relayed to the treating clinician in a timely manner to improve survival and reduce the risk of possible complications. Imaging features that should alert radiologists to IVC injury include contour abnormalities, active extravasation, pseudoaneurysm, and pericaval haematoma. Trauma to the IVC is associated with significant complications. These include exsanguination and refractory shock in the acute period while in the longer term, thrombosis can develop with potential for subsequent pulmonary embolism. Additionally, there are complications that may develop post-surgically including further haemorrhage, IVC stenosis, and infection. We review the spectrum of imaging findings in traumatic IVC injury, which are exemplified with cases from our practice. Furthermore, we discuss important factors to consider during interpretation and the challenges that a radiologist may encounter when making the diagnosis.

Controversies in the diagnosis of renal cell carcinoma with tumor thrombus

Diagnosis and treatment of renal cell carcinoma with venous tumor thrombosis remains a challenge today, requiring multidisciplinary teams, mainly in tumor thrombus levels III-IV. Our objective is to present the various diagnostic techniques used and its controversies. A review of the most relevant related articles between January 2000 and August 2020 has been carried out in PubMed, EMBASE and Scielo. Continuous technological development has allowed progress in its detection, in the approximation of the histological subtype, and in the determination of tumor thrombus level. Regardless of the imaging technique used for its diagnosis (CT, MRI, TEE, ultrasound with contrast), the time elapsed until treatment is vitally important to reduce the risk of complications, some of them fatal, such as pulmonary thromboembolism.

Magnetic resonance imaging demonstration of an unusual triplication anomaly of the inferior vena cava

Knowing congenital anomalies of the inferior vena cava is of clinical importance for radiological interventional procedures and retroperitoneal surgery. We present magnetic resonance imaging of the coincidence of fenestrated right and left inferior vena cava anomalies in a 78-year-old woman. Contrast-enhanced magnetic resonance imaging is an important imaging technique that is preferred in evaluating vascular structures in this locality.

Inferior vena cava-syndrome

Inferior vena cava syndrome (IVCS) is caused by agenesis, compression, invasion, or thrombosis of the IVC, or may be associated with Budd-Chiari syndrome. Its incidence and prevalence are unknown. Benign IVCS is separated from malignant IVCS. Both cover a wide clinical spectrum reaching from asymptomatic to highly symptomatic cases correlated to the underlying cause, the acuity, the extent of the venous obstruction, and the recruitment and development of venous collateral circuits. Imaging is necessary to determine the underlying cause of IVCS and to guide clinical decisions. Interventional therapy has changed the therapeutic approach in symptomatic patients. This article provides an overview over IVCS and focuses on interventional therapeutic methods and results.

Inter-scan and inter-scanner variation of quantitative dual-energy CT: evaluation with three different scanner types

OBJECTIVES

To investigate inter-scan and inter-scanner variation of iodine concentration (IC) and attenuation in virtual monoenergetic images at 65 keV (HU_65keV) in patients with repeated abdominal examinations on dual-source (dsDECT), rapid kV switching (rsDECT), and dual-layer detector DECT (dlDECT).

METHODS

We retrospectively included 131 patients who underwent two abdominal DECT examinations on the same scanner (dsDECT: n = 46, rsDECT: n = 45, dlDECT: n = 40). IC and HU_65keV were measured by placing regions of interest in the liver, spleen, kidneys, aorta, portal vein, and inferior vena cava. Overall IC and HU_65keV for each scanner, their inter-scan differences and proportional variation were calculated and compared between scanner types.

RESULTS

The three scanner-specific cohorts showed similar weight, body diameter, age, sex, and contrast media injection parameters as well as inter-scan differences hereof (p range: 0.23-0.99). Absolute inter-scan differences of HU_65keV and IC were comparable between scanners (p range: 0.08-1.0). Overall inter-scan variation was significantly higher in IC than HU_65keV (p < 0.05). For the liver, rsDECT showed significantly lower inter-scan variation of IC compared to dsDECT/dlDECT (p = 0.005/0.01), while for the spleen, this difference was only significant compared to dsDECT (p = 0.015). Normalizing IC of the liver to the portal vein and of the spleen to the aorta did not significantly reduce inter-scan variation (p = 0.97 and 0.50).

CONCLUSIONS

Iodine measurements across different DECT scanners show inter-scan variation which is higher compared to variation of attenuation values. Inter-scanner differences in longitudinal variation and overall iodine concentration depend on the scanner pairs and organs assessed and should be acknowledged in clinical and scientific DECT applications.

KEY POINTS

• All scanner types showed comparable inter-scan variation of attenuation, while for iodine, the rapid kV switching DECT showed lower variability in the liver and spleen. • Iodine concentration showed higher inter-scan variation than attenuation measurements; normalization to vessels did not significantly improve inter-scan reproducibility of iodine concentration in parenchymal organs. • Differences between the three scanner types regarding overall iodine concentration and attenuation obtained from both timepoints were within the range of average intra-patient, inter-scan differences for most assessed organs and vessels.

Transcatheter Embolization of Renal-Splenic Shunt to Treat Hematemesis

Although sequelae of chronic liver disease are the most common causes of altered pressure dynamics in the portal and splanchnic circulations, there are other mechanisms resulting in increased venous pressures with subsequent development of splenic and gastric varices. We report a case of a patient without portal hypertension, but with bleeding gastric varices with a presumed splenorenal shunt (SRS) on CT. Venography revealed flow reversal through the shunt (directed from the renal vein, into the splenic vein and out the portal vein; a renal-splent shunt (RSR)) and thus an anatomically similar but functionally distinct systemic to mesenteric variant. While being anatomically similar to the well-known SRS, the different flow dynamics necessitate a different approach for treatment and important considerations for the use of any liquid embolic.

Tumor in the veins: an abdominal perspective with an emphasis on CT and MR imaging

Endovenous tumor thrombus in abdomen should be accurately diagnosed as it is a significant finding that may change medical and surgical treatment approaches. As some underlying reasons for endovenous tumor thrombi are relatively rare and imaging findings may be quite subtle, they can be easily overlooked which may have important clinical consequences. In this paper, we described the various imaging aspects of endovenous tumor thrombi originating from various tumor types in different venous structures of the abdomen.

Asymptomatic azygos vein overflow in a young patient with primary mediastinal seminoma

The azygos system is the most important pathway for decompression of the superior vena cava (SVC) when a blood flow obstruction to the right atrium is present. Thoracic and mediastinal malignancies, mainly lung cancers, are responsible for 60%–85% of superior vena cava syndrome (SVCS) cases. An uncommon origin of SVCS is primary malignant mediastinal germ cell tumor (PMMGCT) which represent 1%–4% of all mediastinal tumors and can be divided into two broad groups: seminomas and nonseminomatous germ cell tumors (NSGCTs). Primary mediastinal seminomas clinical presentation is often nonspecific, even if the majority of patients present with superior vena cava involvement. Here, we present the radiologic features of asymptomatic azygos system overflow in a patient with primary mediastinal seminoma.

CT variants of the caudal vena cava in 121 small breed dogs

Computed tomography is increasingly used as a treatment planning method in canine patients with diseases of the retroperitoneum, however, published information on normal variations in the caudal vena cava (CVC) are currently lacking. The objectives of this retrospective descriptive study were to characterize CVC variants using CT angiography in a sample of small breed dogs and localize the CVC bifurcations for each variant. Inclusion criteria were small breed dogs (weight ≤ 15) that underwent contrast-enhanced CT scans of the CVC, abdominal aorta, and CVC tributaries. A total of 121 small breed dogs were sampled. Four right-sided and one left-sided CVC variations were identified: normal (88/121, 72.7%), caudal-partial split (17/121, 14.0%), partial duplication (8/121, 6.6%), complete duplication (7/121, 5.8%), and left-sidedness (1/121, 0.8%). The mean lumbar vertebral levels of the CVC bifurcation were L6.39 ± 0.41, L5.70 ± 0.35, L4.39 ± 0.42, L2.74 ± 0.38, and L6.4 in the normal, caudal-partial split, partial duplication, complete duplication, and left-sidedness types, respectively. The location of the CVC bifurcation, the relationship between the aortic trifurcation and the CVC bifurcation, and the location of the bilateral deep circumflex iliac veins with respect to the CVC bifurcation were significantly different among the right-sided types (P ≤ .001). Bilateral deep circumflex iliac veins joined to the ipsilateral common iliac veins and the CVC in the caudal-partial split and duplication types, respectively. The results of this study indicated that canine CVC variants may be frequent and should be considered during surgery or diagnostic imaging of the retroperitoneum.

An unusual case of deep venous thrombosis in a young patient: congenital absence of the infrarenal portion of the inferior vena cava

Deep venous thrombosis (DVT) is a commonly encountered diagnosis in clinical practice with a variety of well-established risk factors. Congenital absence of the inferior vena cava (IVC) is an extremely rare but established risk factor for DVT. Patients who develop DVTs are at high risk of long-term complications, including DVT recurrence and post-thrombotic syndrome. Here we report a rare case of a 27-year-old female who presented with an extensive DVT of the right lower extremity secondary to complete absence of the infrarenal portion of the IVC, confirmed on computed tomography. There is little consensus regarding the appropriate management of this patient population, and a brief review of the current evidence follows.

Polysplenia syndrome with situs ambiguous, common mesentery, and IVC interruption discovered incidentally in an adult

Polysplenia syndrome associates multiple spleens to other malformations, most frequently cardiac, vascular, visceral, and biliary malformations. Polysplenia has been described mainly in childhood owing to critical anatomic malformations related to cardiac defects or biliary atresia. We present a case of polysplenia syndrome found in a 58-year-old man. Only those with mild anatomical abnormalities reach adulthood without a diagnosis. Radiological examinations are helpful to the diagnosis by ascertaining the location and number of spleens, location of other organs in the chest and abdomen, and identification of other associated anomalies.

Azygos and hemiazygos continuation: An occasional finding in emergency department

Interruption of the inferior vena cava (IVC) with azygos continuation is a rare congenital anomaly, in which the IVC is interrupted below the hepatic vein and venous return beyond this point is restored by the dilated azygos and hemiazygos veins draining into the superior vena cava. A case of the interruption of the IVC with azygos/emyazygos continuation for the absence of the hepatic segment of IVC, left renal vein duplication, and polysplenia is reported. The embryologic, clinical, and radiological significance are discussed.

The diagnosis is suggested by X-ray, but contrast-enhanced multidetector computed tomography is the method of choice to diagnose this venous anomaly and reveals the aberrant vascular structures.

Awareness of different congenital anomalies of IVC is important to surgeons and cardiologists and is necessary for radiologists to avoid diagnostic pitfalls and for preoperative planning: they should be remembered because they can influence several surgical interventions and endovascular procedures. Accidental ligation of the azygos vein is fatal and cardiac catheterization using the lower extremity vein is troublesome in patients with this condition.

Bilobed spleen, transposition of the inferior vena cava and Riedel lobe: an extremely rare imaging finding in the same case

There is a wide range of congenital anomalies of the spleen regarding its shape, location, number, and size. Most of these congenital anomalies are commonly detected on ultrasonography, CT, or MRI and may sometimes represent a challenging diagnosis for radiologists and clinicians. The bilobed spleen is an extremely rare form of congenital anomaly. In most cases, it is accidentally discovered during abdominal surgeries. The bilobed spleen is usually large in size when compared with the normal spleen; hence, it is more liable to trauma. Transposition of the inferior vena cava (IVC; also known as left-sided IVC) refers to a very rare variant course of the IVC. The most common variations are duplicate IVC, as well as retroaortic left renal vein and circumaortic venous rings. Left-sided IVC occurs in 0.17–0.5% of the general population. Diagnosis of left-sided IVC is important when planning vascular procedures like portosystemic shunt, the placement of an IVC filter, nephrectomy, and renal transplant. There should be an awareness of the Riedel lobe, which is a common anatomical variant of the liver, as it can simulate a mass. Its misidentification as a pathological abdominal mass can lead to surgery; pathology can also occur (e.g. malignancy or even torsion). In this report, we presented a case of a bilobed spleen that was misdiagnosed as a left renal mass during routine abdominal ultrasonography in a 25-year-old female who complained of recurrent left hypochondrium pain. The bilobed configuration was confirmed with MRI and ultrasound examination of the abdomen.

Various congenital anomalies of the inferior vena cava: review of cross-sectional imaging findings and report of a new variant

The inferior vena cava (IVC) is an important structure receiving a large amount of venous return and is associated with various congenital disorders. Advances in diagnostic imaging and its increasing accessibility have led to an increase in the incidental detection of IVC anomalies. Congenital anomalies of the IVC are not uncommon and are occasionally critical to treatment planning. However, they are frequently overlooked in abdominal imaging. The IVC is composed of four segments (intrahepatic, suprarenal, renal, and infrarenal), and each segment arises from different embryonic structures in a complex process. Anomalies of the IVC can be classified according to the involved segment. Familiarity with the variety of IVC anomalies seen on imaging is vital for correctly diagnosing and managing patients in daily practice.

Assessing venous thrombus in renal cell carcinoma: preliminary results for unenhanced 3D-SSFP MRI

AIM

To test the potential of unenhanced cardiac- and respiratory-motion-corrected three-dimensional steady-state free precession (3D-SSFP) magnetic resonance imaging (MRI) for the assessment of inferior vena cava (IVC) thrombus in patients with clear-cell renal cell carcinoma (cRCC), compared to standard contrast-enhanced (CE)-MRI and CE-computed tomography (CT).

MATERIALS AND METHODS

Eighteen patients with cRCC and IVC thrombus, who received CE-MRI and 3D-SSFP at 1.5 T between June 2015 and December 2017, were included. The diagnostic performance of 3D-SSFP in determining the level of thrombus extension, contrast-to-noise ratio (CNR), and image quality were compared with standard MRI/CT and validated against intraoperative and histopathology results.

RESULTS

There was 100% agreement between 3D-SSFP, 83.3% agreement between CE-MRI, and 71.4% agreement between CE-CT and surgical findings regarding the level of IVC thrombus. In addition, 3D-SSFP showed a slightly superior estimate of pathological IVC volume. 3D-SSFP reached a significantly higher CNR in the supra- and infrarenal IVC compared to the morphological sequence T2-weighted half-Fourier axial single-shot fast spin-echo (T2-HASTE) and all phases of CE-MRI. More specifically, 3D-SSFP showed a significantly higher CNR in the infrarenal IVC (mean CNR of 10.09±5.74 versus 4.21±2.33 in the delayed phase, p≤0.001) and in the suprarenal IVC (mean CNR of 9.22±4.11 versus 4.84±5.74 in the late arterial phase, p=0.015). CE-CT also was significantly inferior to 3D-SSFP (p≤0.01) and slightly inferior to CE-MRI (p>0.05). The thrombus delineation score for 3D-SSFP (4.38±0.67) was higher compared to CE-MRI (3.76±0.56, p=0.005).

CONCLUSION

This preliminary study indicates that 3D-SSFP can achieve an accurate assessment of IVC thrombus in cRCC patients without the need for contrast medium administration, being superior to standard MRI and CT.

Renal cell carcinoma with venous extension: prediction of inferior vena cava wall invasion by MRI

BACKGROUND

Renal cell carcinoma (RCC) are accompanied by inferior vena cava (IVC) thrombus in up to 10% of the cases, with surgical resection remaining the only curative option. In case of IVC wall invasion, the operative procedure is more challenging and may even require IVC resection. This study aims to determine the diagnostic performance of contrast-enhanced magnetic resonance imaging (MRI) for the assessment of wall invasion by IVC thrombus in patients with RCC, validated with intraoperative findings.

METHODS

Data were collected on 81 patients with RCC and IVC thrombus, who received a radical nephrectomy and vena cava thrombectomy between February 2008 and November 2017. Forty eight patients met the inclusion criteria. Sensitivity and specificity as well as the positive and negative predictive values were calculated for preoperative MRI, based on the assessments of the two readers for visual wall invasion. Furthermore, a logistic regression model was used to determine if there was an association between intraoperative wall adherence and IVC diameter.

RESULTS

Complete occlusion of the IVC lumen or vessel breach could reliably assess IVC wall invasion with a sensitivity of 92.3% (95%-CI: 0.75-0.99) and a specificity of 86.4% (95%-CI: 0.65-0.97) (Fisher-test: p-value< 0.001). The positive predictive value (PPV) was 88.9% (95%-CI: 0.71-0.98) and the negative predictive value reached 90.5% (95%-CI: 0.70-0.99). There was an excellent interobserver agreement for determining IVC wall invasion with a kappa coefficient of 0.90 (95%CI: 0.79-1.00).

CONCLUSIONS

The present study indicates that standard preoperative MR imaging can be used to reliably assess IVC wall invasion, evaluating morphologic features such as the complete occlusion of the IVC lumen or vessel breach. Increases in IVC diameter are associated with a higher probability of IVC wall invasion.

Congenital membranous occlusion of the suprahepatic inferior vena cava in a pediatric liver transplant

Congenital membranous occlusion of the inferior vena cava (IVC) in pediatric liver recipients may present with outflow occlusion and if unrecognized, result in graft loss. Prompt evaluation of outflow obstruction in the setting of unexplained inflow compromise is paramount. We report a case of successful IVC reconstruction in a patient with recurrent hepatic artery thrombosis (HAT). A 2-year-old child with history of two liver transplantations developed fevers, ascites, and abdominal tenderness one month after her second liver transplant. Hepatic duplex revealed decreased flow in the hepatic artery and IVC venogram revealed patent hepatic veins with occlusion of the suprahepatic IVC. We performed reconstruction of her suprahepatic IVC to intrapericardial IVC using an end-to-side technique after complete mobilization of the liver. Recovery was uneventful and the patient has been doing well for the last 5 years.

Common Resident Errors When Interpreting Computed Tomography of the Abdomen and Pelvis: A Review of Types, Pitfalls, and Strategies for Improvement

OBJECTIVE

The purpose of this study was to identify common errors that radiology residents make when interpreting abdominopelvic (AP) computed tomography (CT) while on call, to review the typical imaging findings of these cases, and to discuss strategies for improvement.

MATERIALS AND METHODS

AP (or chest, abdomen, pelvis) CTs from 518 weekend senior call shifts (R3 or R4) were retrospectively reviewed. Discrepancies between preliminary and final reports were identified and then rated by whether the miss could impact short-term management. The imaging findings from the cases were reviewed.

RESULTS

A total of 4695 CTs were reviewed, revealing a total of 145 discrepancies that could affect short-term clinical management (miss rate 3.1%). The most common misses were related to blood clots (13.8%), colitis (8.3%), misplaced lines or tubes (6.9%), or pyelonephritis (5.5%). Common pitfalls and strategies from improved detection are discussed using image examples.

CONCLUSIONS

Through increased attention to the vasculature, colon, devices, and kidneys, trainees may improve their discrepancy rates and improve on-call reporting.

Malignant Venous Obstruction: Superior Vena Cava Syndrome and Beyond

Venous obstruction in the cancer population can result in substantial morbidity and, in extreme cases, mortality. While venous obstruction can be caused by both benign and malignant etiologies in this population, the management of malignant venous obstruction as a palliative measure can be somewhat nuanced with respect to nonprocedural and procedural management, both with respect to treatment of the underlying malignancy as well as treatment of venous hypertension, which may be associated with venous thrombosis. Symptom severity, primary malignancy, functional status, and prognosis are all fundamental to the patient workup and dictate both the timing and extent of endovascular intervention. The morbidity and mortality associated with malignant obstructions of central venous structures, specifically the superior vena cava and inferior vena cava, can be significantly improved with endovascular management in appropriately selected patients. Thus, the pertinent literature regarding the clinical presentation, workup, and endovascular management of malignant central venous obstruction syndromes, with directed attention to superior vena cava syndrome and inferior vena cava syndrome, will be reviewed in this article.

Multidisciplinary retroperitoneal and pelvic soft-tissue sarcoma case conferences: the added value that radiologists can provide

Clinical Vignette: A 50-year-old woman presents to the emergency department with increasing abdominal pain. Abdominal computed tomography imaging reveals an expanded inferior vena cava-filling defect that is suspicious for a retroperitoneal sarcoma, possibly a primary leiomyosarcoma of the inferior vena cava. The surgery team discusses the case with the radiologist, and all agree that there are multiple challenges with obtaining a tissue diagnosis and determining resectability. Thus, it is decided that this patient should be discussed at a multidisciplinary case conference. In the present article, we feature a case-based scenario focusing on the role of the radiologist in this type of multidisciplinary team.