Case of Isolated Absence of the Azygos Vein: Evaluation Using Photon-counting Detector CT.

The isolated absence of the azygos vein was incidentally found on computed tomography (CT) examination in a 60-year-old female. The exact anomaly can be evaluated on high-resolution images of 0.4-mm slice thickness with low keV using photon-counting detector CT. The azygos vein, including the azygos arch, was absent, and a mildly dilated hemiazygos vein flowed to the left brachiocephalic vein through the left superior intercostal vein. A hemiazygos vein connected the left renal vein at the level of the first lumbar vertebra. This patient was the second patient to undergo evaluation using volume rendering images. High-resolution maximum-intensity projection images were useful for assessing the anatomy. Radiation dose was decreased compared with that in conventional CT.

CT findings of an incidental segmental aplasia of the caudal vena cava with azygos continuation in a guinea pig (Cavia porcellus).

Background: Segmental aplasia of the caudal vena cava (CVC) with azygos continuation is a congenital malformation macroscopically described in mammals including humans, dogs, and rodents. It is usually detected as an incidental finding and the final diagnosis is reached by computed tomography (CT), fluoroscopy, or post-mortem dissection. Case Description: A 3-year-old guinea pig (Cavia porcellus) presented with subacute dyspnea. A computed tomographic examination was performed for the evaluation of subtle pulmonary changes previously suspected on conventional radiography, and a segmental aplasia of the CVC with azygos continuation was identified as an incidental finding. Conclusion: According to database negative results, this is the first report describing a segmental aplasia of the CVC and azygos continuation in a guinea pig by CT.

On the way to the azygos vein: a road of return rather than ruined.

BACKGROUND: The malposition of central venous catheters (CVCs) may lead to vascular damage, perforation, and even mediastinal injury. The malposition of CVC from the right subclavian vein into the azygos vein is extremely rare. Here, we report a patient with CVC malposition into the azygos vein via the right subclavian vein. We conduct a comprehensive review of the anatomical structure of the azygos vein and the manifestations associated with azygos vein malposition. Additionally, we explore the resolution of repositioning the catheter into the superior vena cava by carefully withdrawing a specific length of the catheter. CASE PRESENTATION: A 79-year-old female presented to our department with symptoms of complete intestinal obstruction. A double-lumen CVC was inserted via the right subclavian vein to facilitate total parenteral nutrition. Due to the slow onset of sedative medications during surgery, the anesthetist erroneously believed that the CVC had penetrated the superior vena cava, leading to the premature removal of the CVC. Postoperative contrast-enhanced computed tomography of the chest confirmed that the central venous catheter had not penetrated the superior vena cava but malpositioned into the azygos vein. The patient was discharged 15 days after surgery without any complications. CONCLUSIONS: CVC malposition into the azygos vein is extremely rare. Clinical practitioners should be vigilant regarding this form of catheter misplacement. Ensuring the accurate positioning of the CVC before each infusion is crucial. Utilizing chest X-rays in both frontal and lateral views, as well as chest computed tomography, can aid in confirming the presence of catheter misplacement.

A remarkable case report of an interrupted inferior vena cava with hemiazygos and transhepatic continuation.

Inferior vena cava (IVC) interruption with azygos/hemiazygos continuation is an extremely uncommon congenital vascular anomaly, which may present with multiple variants. As a result, it is challenging to find in the literature the same anatomical variant. We report a unique case of an interrupted IVC with hemiazygos and transhepatic continuation in an 83-year-old female patient. The case was evaluated by performing Computed Tomography (CT) as imaging modality, with a multiphase protocol, able to detect accurately this complex vascular anomaly. The purpose of this case report is not only to present this remarkable case but also to briefly show the types of interrupted IVC, starting from the anatomy and the embryology of the IVC and the azygos system, and to discuss the value of imaging in detecting the vascular anomaly.

Normal variations of the superior vena cava and azygos venous system depiction by CT scan in the adult Thai population.

BACKGROUND: Identification of normal variations to the thoracic central venous system anatomy is essential in radiological intervention and cardiothoracic surgery to prevent complications. PURPOSE: To estimate the prevalence and pattern of normal variations of superior vena cava (SVC) and azygos venous system as well as factors associated with normal variations of SVC. MATERIAL AND METHODS: Venous-phase chest CT of 1336 patients were retrospectively reviewed. Age, sex, and underlying disease were recorded. SVC diameter and cross-sectional area were measured to evaluate for associations with normal variations. RESULTS: The prevalence of normal anatomical variations of SVC and azygos venous system were 0.3% and 1.5%, respectively. Duplicated SVC was the most common variations. The most common variation for the azygos venous system was the connection between the hemiazygos and accessory hemiazygos veins draining into the left brachiocephalic vein (12/1336 cases, 0.9%). The median (interquartile range [IQR]) cross-sectional area compared between normal SVC (297.2 mm2) and duplicated SVC (223.5 mm2) showed a statistically significant difference (P = 0.033). CONCLUSION: This study determined the prevalence of rare normal variations of the azygos venous system, a connection between the hemiazygos and accessory hemiazygos veins draining into the left brachiocephalic vein. The prevalence of normal variations of the SVC and azygos venous system in the adult Thai population was similar with that of previous publications. Cross-sectional area was the only factor with a significant association with SVC variations.

Long-term results of one-and-a-half ventricle repair with open azygos vein.

BACKGROUND: The one-and-a-half ventricle repair (1.5VR) is an option for definitive surgery of cardiac defects with hypoplastic right ventricle (RV). The 1.5VR with open azygos vein was reported to provide a theoretical advantage of decompressing the supra vena cava (SVC) or the right atrium in patients with SVC hypertension or severe RV dysfunction. The aim of this study is to review and evaluate our experience with this procedure in the long-term period. METHODS: Medical records of the patient undergoing 1.5VR with open azygos vein between January 2000 and December 2019 were reviewed retrospective. Pre- and postoperative echocardiography and cardiac catheterization data were also analyzed. RESULTS: 4 patients underwent the 1.5VR with open azygos vein. The median age at time of surgery was 2.2 years, and the median weight was 9.8 kg. The median tricuspid valve (TV) Z-score was - 3.5, the median right ventricular end-diastolic volume (RVEDV) was 54.0% of normal. There were no operative death and early adverse events. Median follow-up time was 17.1 years. There were no late death and re-operation during the follow-up. The postoperative TV diameter and RVEDV were larger than preoperative data in 3 of 4 patients. CONCLUSIONS: The 1.5VR with open azygos vein is a good surgical option for congenital heart disease with hypoplastic RV. The TV and RVEDV may grow and biventricular conversion may be possible.

An Incidental Discovery of Supracardiac Left-sided Partial Anomalous Pulmonary Connection and Dilation of the Azygos Vein Detected in Adulthood.

INTRODUCTION: Anomalous pulmonary venous connection is a rare congenital variant of the pulmonary veins drained into the right atrium. The left-side partial anomalous pulmonary connections are usually detected in adulthood and occasionally drain into the left brachiocephalic vein. CASE DESCRIPTION: An asymptomatic 63-year-old woman with a known history of left carotid body paraganglioma was admitted to our institution to evaluate this tumor by computed tomography angiography of the neck and brain. As an incidental finding, CTA demonstrated a supracardiac partial anomalous pulmonary venous connection between the left upper pulmonary vein and the left innominate via the vertical vein. Additionally, dilation of the azygos vein was observed. CONCLUSION: Supracardiac left-sided partial anomalous pulmonary venous connection is a rare vascular variant, usually asymptomatic and found incidentally in adults.

Two Cases of Interrupted Inferior Vena Cava with Azygos / Hemiazygos Continuation.

Interrupted inferior vena cava (IVC) is a rare disease, occurring either in isolation or in association with asplenia or polysplenia syndromes. Infrahepatic part of the IVC is absent representing the failure of fusion of the vitelline and subcardinal embryological portions of the IVC. It is replaced by an enlarged azygos or hemiazygos vein continuing into the thorax, either into the superior vena cava or into the brachiocephalic veins. We present two cases of interrupted IVC, one occurring in isolation with hemiazygos continuation and discovered incidentally, and the second one is a child with azygos continuation, associated with polysplenia syndrome. Key Words: Inferior vena cava, Polysplenia, Azygous vein, Hemiazygos vein.

Azygos Vein Enlargement Secondary to Superior Vena Cava Syndrome on 18 F-FDG PET/CT.

ABSTRACT: Obstruction of the blood flow from the superior vena cava (SVC) to the right atrium causes the SVC syndrome. The azygos system is the most important way to overcome SVC obstruction. Azygos vein enlargement can be seen secondary to the SVC syndrome. Although a few cases showing 18 F-FDG uptake along the SVC in SVC syndrome were reported before, 18 F-FDG PET/CT findings of azygos vein enlargement have not been documented yet. Herein, we presented an intriguing case of azygos vein enlargement secondary to SVC syndrome on 18 F-FDG PET/CT.

Intrapulmonary course of superior caval vein associated with azygos lobe.

We report a case of a 4-month-old boy with tetralogy of Fallot where computed tomography angiography incidentally revealed the presence of a unique extra-mediastinal and intrapulmonary course of the superior caval vein within the anterior portion of the azygos fissure.

Thoracoscopic approach to the resection of idiopathic azygos vein aneurysm: a case report.

BACKGROUND: Azygos vein aneurysm (AVA) is a rare thoracic pathological entity that mimics a posterior mediastinal mass. However, the pathogenesis of primary azygos vein aneurysms is not clear and its pathology is still being discussed. Some of the AVA are asymptomatic and usually discovered accidentally by routine physical examination. CASE PRESENTATION: We report the case of a 37-year-old woman who had an azygos vein arch aneurysm with no obvious clinical symptoms. With the analysis of clinical features of the case and AVA morphological characteristics, the AVA was found by a chest computed tomography. Then, enhanced chest computed tomography showed a soft-tissue mass (4.9 × 3.7 × 3.2 cm) in the right posterior mediastinum, which was connected to the superior vena cava and significantly enhanced with contrast agent stratification. The density of the tumor in the delayed stage was the same as that in the azygos vein. The patient underwent video-assisted thoracoscopic surgery. Histopathological evaluation of the surgical biopsy specimen proved to be a completely thrombosed aneurism of the azygos vein arch. CONCLUSIONS: AVA is a rare pathology that must be taken into consideration during the differential diagnosis of right posterior mediastinal masses. Thoracoscopic surgery is one of the most preferred treatment options for azygos vein aneurysm.

Presurgical assessment of flow variability in an azygos vein aneurysm using 4D-flow MRI.

Azygos vein aneurysm (AVA) is necessary to prevent pulmonary embolism due to the outflow of a thrombus or rupture of the aneurysm. However, there is no established modality to assess the properties of AVA. Time-resolved three-dimensional phase-contrast magnetic resonance imaging (4D-flow MRI) has been used to examine the hemodynamics in various fields. We report a case of AVA to evaluate the flow variability and adhesions of surrounding tissues using 4D-flow MRI. The findings of the study suggested aneurysm turbulence and the absence of thrombi. The cine image, which showed a sliding wall synchronized to the heartbeat, indicated no adhesion to the superior vena cava. Based on these results, the thoracoscopic approach was deemed possible preoperatively. Thoracoscopic AVA resection was performed, and the postoperative course was uneventful. This study documented the utility of 4D-flow MRI for a detailed evaluation of AVA.

Prenatal diagnosis of hepatic interruption of the inferior vena cava with azygos/hemiazygos continuation without structural heart defects: A case series.

OBJECTIVES: To describe fetal spectrum and echocardiographic characteristics of interrupted inferior vena cava (IIVC) with azygos/hemiazygous continuation without other structural heart defects and to evaluate its association with visceral heterotaxy and isomerism, extracardiac and genetic anomalies, and to review neonatal outcome. METHODS: This was a retrospective study of 14 fetuses with a confirmed diagnosis of IIVC with normal intracardiac anatomy. The following variables were collected; indication for referral, gestational age at diagnosis; associated isomerism and visceral heterotaxy, heart rhythm, genetic and extracardiac abnormalities, and fetal/neonatal outcome. RESULTS: Among 36 fetuses with IIVC, 14 cases (38.8%) had normal intracardiac anatomy. These IIVC cases correspond to 0.19% (14/7250) of all fetal cardiac examinations, and to 1.5% (14/922) of all cardiac abnormalities. Six patients had visceral abnormalities. Atrial appendage morphology was clearly depicted in three fetuses, both appendages were left. One fetus had bradyarrhythmia revealing atrial ectopic rhythm. Six fetuses did not have any concomitant cardiac or visceral abnormalities, therefore regarded as isolated. All babies were delivered at term with a good prognosis. CONCLUSION: Our study has shown that almost half of the IIVC cases without intracardiac structural anomalies displayed other findings of isomerism while the other half was isolated benign vascular variant. Therefore, prenatal diagnosis of IIVC should prompt a comprehensive evaluation for cardiac, situs, and visceral anomalies. The outcome is favorable.