Search

Spectral analysis of ultrasound radiofrequency backscatter has the potential to identify intercostal blood vessels during ultrasound-guided placement of paravertebral nerve blocks and intercostal nerve blocks. Autoregressive models were used for spectral estimation, and bandwidth, autoregressive order and region-of-interest size were evaluated. Eight spectral parameters were calculated and used to create random forests. An autoregressive order of 10, bandwidth of 6 dB and region-of-interest size of 1.0 mm resulted in the minimum out-of-bag error. An additional random forest, using these chosen values, was created from 70% of the data and evaluated independently from the remaining 30% of data. The random forest achieved a predictive accuracy of 92% and Youden's index of 0.85. These results suggest that spectral analysis of ultrasound radiofrequency backscatter has the potential to identify intercostal blood vessels. (jokling@siue.edu) © 2018 World Federation for Ultrasound in Medicine and Biology.

AIM The surgical assumption of responsibility of the pancreatic pain requires either a truncular coelioscopic or radicular neurectomy of greater splanchnic nerves (gsn). The goal of our work is to describe the way and relations of the right gsn which are variable and rarely described. This constitutes an undeniable peroperational hemorrhagic risk during splanchnicectomy. MATERIAL AND METHODS After a double side thoracotomy and a bilateral sterno-clavicular desarticulation on 15 adult cadaveric subjects preserved by method of Winckler we removed the sterno-costal drill plate as well as the ventral rib arch and proceeded to a mediastinal evisceration of the thorax. Then we respected only the thoracic aorta and the oesophagus, the azygos venous system, the thoracic duct and the thoracic sympathetic chain. In some of the subjects, the azygos vein was injected (after catheterization of its stick) using gelatine coloured with blue paint. We studied the way and vascular relations of the right gsn. We measured the transverse distances between the origin of the gsn on one hand and the longitudinal axes of the azygos vein and the thoracic duct on the other hand. RESULTS The relations of the right gsn trunk during its way related to the azygos vein in particular its constitutive origin and its affluents: ascending lumbar vein and twelfth intercostal vein. Sometimes the thoracic duct even a lymphatic node was near the gsn in the posterior infra-mediastinal space. A classification of the way and vascular relations of the right gsn in the thorax identified 3 anatomical types. The average distances separating the right gsn on one hand from the azygos vein and the thoracic duct on the other hand were respectively 5.7 mm and 11.2 mm. CONCLUSION The vascular relations of the right gsn are very variable from one subject to another but primarily venous, sometimes lymphatic. They concerned the great thoracic vessels whose respect is essential in particular at the time of mini-invasive access procedure for a cœlioscopic splanchnicectomy.

Objective The superior vena cava (SVC) obstruction by malignant diseases is either by direct invasion and compression or by tumour thrombus of the SVC. Whatever is its cause, obstruction of the SVC causes elevated pressure in the veins draining into the SVC and increased or reversed blood flow through collateral vessels. Severity of the syndrome depends on the collateral vascular system development. Therefore, imaging of the collateral veins with variable location and connection is important in determining the extension and management of the disease. Our aims are to describe collateral vessels of the superior vena cava syndrome (SVCS) related with the malignant diseases and to assess the ability of multi-detector row CT with multiplanar and 3D volume rendering techniques in determining and describing collateral circulations. Materials and methods We present CT angiography findings of seven patients with small cell carcinoma of the lung (n = 2), squamous cell carcinoma of the lung (n = 3), Hodgkin disease of the thorax (n = 1), and squamous cell carcinoma of the oesophagus (n = 1). The patients received contrast-enhanced CT scans of the chest and abdomen on a multi-detector row CT during breath holding at suspended inspiration. Results CT images revealed the cause and level of the SVC obstruction in all patients with axial and multiplanar reconstructed images. The SVC showed total obstruction in five patients and partial obstruction in two patients. The most common experienced collateral vessels were azygos vein (6), intercostal veins (6), mediastinal veins (6), paravertebral veins (5), hemiazygos vein (5), thoracoepigastric vein (5), internal mammary vein (5), thoracoacromioclavicular venous plexus (5), and anterior chest wall veins (5). While one case showed the portal-systemic shunt, V. cordis media and sinus coronarius with phrenic veins were enlarged in two cases, and the left adrenal vein was enlarged in a patient. In one case, the azygos vein with reversed blood flow was drained into both inferior vena cava and hemiazygos vein with the left renal vein. Conclusion Multi-detector row CT with multiplanar and 3D imaging is an effective tool in evaluation of the SVCS and has a greater advantage than the other imaging techniques. 3D volume rendering is a useful technique in determining and describing collateral circulations in addition to the primary disease process.

Background/Purpose Some children dependent on total parenteral nutrition for long periods have no more axillary, internal jugular, external jugular, saphenous, and femoral veins available for cannulation. In such patients, the central venous system can still be accessed via the azygos vein by placing an implantable port catheter through one of the right posterior intercostal veins. This is the first known description of such procedure. Methods We report the use of the second and third right intercostal veins for placement of the catheter by right intrapleural thoracotomy in 2 pediatric patients with short gut syndrome. Results Recovery from the thoracotomy was uncomplicated, and the patients could receive complete intravenous nutritive mixtures immediately after the insertion of the catheter. Both patients remain dependent on total parenteral nutrition and are awaiting an intestinal transplantation. Conclusion The knowledge of alternate routes to obtain central venous access for prolonged parenteral nutrition is critically important, and the azygos system can be used when more accessible veins are unavailable.

This article provides a practical approach to the clinical implications and importance of understanding the collateral venous anatomy of the thorax. Routine radiography, conventional venography, computed tomography (CT), and magnetic resonance (MR) imaging studies provide correlative anatomic models for the demonstration of how interconnecting collateral vascular networks within the thorax maintain venous stability at all times. Five major systems comprise the collateral venous network of the thorax (Fig. 1). These include the paravertebral, azygos-hemiazygos, internal mammary, lateral thoracic, and anterior jugular venous systems (AJVS). The five systems are presented in the following sequence: (a) a brief introduction to the importance of catheter position and malposition in understanding access to the thoracic venous system, (b) the anatomy of the azygos-hemiazygos systems and their relationship with the paravertebral plexus, (c) the importance of the AJVS, (d) 'loop' concepts interconnecting the internal mammary and azygos-hemiazygos systems by means of the lateral thoracic and intercostal veins, and (e) the interconnecting venous networks on the thoracic side of the thoracoabdominal junction. Certain aspects of the venous anatomy of the thorax will not be discussed in this chapter and include (a) the intra-abdominal anastomoses between the superior and inferior vena cavae (IVC) via the internal mammary, lateral thoracic, and azygos-hemiazygos systems (beyond the scope of this article), (b) potential collateral vessels involving vertebral, parascapular, thyroidal, thymic, and other smaller veins that might anastomose with the major systems, and (c) anatomic variants and pitfalls that may mimic pathologic conditions (space limitations).

A new preparation is described for the study of the microcirculation of the rat diaphragm by in vivo microscopy. After midline laparotomy, the abdominal site of the diaphragm muscle was exposed. The rat was mechanically ventilated and placed in the Trendelenburg position, thus allowing a microscope placed on a three-dimensional articulated system to be set up perpendicular to the diaphragm. The diaphragm was then transilluminated by inserting fiberoptic microprobes into the thorax acvity by thoractomy in the fifth intercostal space. This preparation allowed us to describe the morphological characteristics of the arteriolar network in vivo. As regards the venular network, two parts were distinguished: one part collects the blood of the external half of the diaphragm, runs roughly parallel to the arterioles, and converges toward the internal mammary and intercostal veins; the other part collects the blood of the central half of the diaphragm and converges on the central venous arcade along its central tendon. Anastomotic channels between these two parts were observed, as well as spontaneous inversion of the direction of the blood flow, indicating the presence of unsteady pressure gradients in some branches of the venular network. Capillary density was also studied by measuring intercapillary distance, whose mean value was 21.43 ± 0.67 μm. No differences in intercapillary distance were found between the external and central parts of the diaphragm. In conclusion, we describe a preparation which allowed us to study the diaphragmatic microcirculation for at least 2 hr under good hemodynamic conditions. The study of this specific microcirculation is important because the diaphragm's metabolism and functions are specific and because it is essential to life that its perfusion should be adapted to its specific metabolic requirements.

innominate and intercostal veins. PTH gradients assist in localization of parathyroid adenomas. A correlation between surgical pathology and parathyroid venous sampling is made. Conclusion and/or Teaching Points: Parathyroid venous sampling is an effective tool in the evaluation of parathyroid adenoma, particularly in the setting of hyperparathyroidism and negative non-invasive imaging. Interventional radiologists should become familiar with this procedure as it may be a last resort imaging modality.

Learning Objectives To facilitate widespread utilization of the parathyroid venous sampling, this pictorial assay reviews normal anatomy and its variants of considerable clinical importance. We will also present the problems and challenges they pose for the interventional radiologist. Background Parathyroid venous sampling for para-thyroid hormone (PTH) is a highly promising method for localization and diagnosis of parathyroid tumors. Sampling of small veins is the goal. The reported sensitivity of parathyroid venous sampling is 70-80%. However, patients with congenital variation in anatomy and also those with distorted anatomy due to previous surgery can sometime present significant challenge to successful completion of bilateral parathyroid venous sampling resulting in false negative test. Clinical Findings/Procedure Details Technical Details : This pictoral review presents parathyroid venous anatomy along with the details of catheterization and retrograde venography of the parathyroid venous bed wherever necessary. In the entire series of no significant complication has occurred. Normal Anatomy and Variants : The thyroid venous bed is composed of: (a) a diffusely anastomosing, valveless plexus of veins arising from and investing the thyroid gland; and (b) paired, draining superior, middle and inferior thyroid veins. - Superior thyroid veins - Middle thyroid veins - Inferior thyroid veins - most common patterns - Thymic mediastinal veins - Azygos vein and left superior intercostal veins - Few confusing veins such as anterior jugular and the vertebral veins as well as mediastinal veins. - Interesting cases Conclusion and/or Teaching Points The roentgenographic anatomy of parathyroid veins is presented. As usual with venous anatomy, variations from the preceding standard description are common. Parathyroid drainage occurs predominantly via the inferior thyroid vein. Although inferior thyroid drainage is variable, bilateral samples could be obtained in a high percentage of cases. Probably least important for parathyroid drainage, the superior thyroid was the most constant and predictable of the thyroid veins.

Persistence of a left superior vena cava is a congenital anomaly of considerable interest but by itself exerts no apparent adverse affect on cardiac function. It may occur as an isolated lesion but more often it is associated with many congenital cardiac anomalies. Heretofore it could only be discovered at autopsy or cadaver dissection, but angiocardiography and cardiac catheterization have made possible its recognition during life. This report is a summary of the findings of 11 cases detected by these methods at this center. Embryology In early development, the cephalic portion of the embryo is drained by bilateral symmetrical right and left anterior cardinal veins. These join the posterior cardinal veins near the heart and form the right and left ducts of Cuvier which enter the sinus venosus (Figure 1A). During the eighth week of fetal life, an oblique communication forms between the anterior cardinal veins and shunts blood from the left yein to the right. This vessel becomes the left innominate vein. The development of the left innominate vein is followed by atrophy of the left anterior cardinal vein. It normally persists as the first left intercostal vein. The left duct of Cuvier persists as the oblique vein of the left atrium which enters the coronary sinus. The latter structure is derived from the left half of the sinus venosus. The right duct of Cuvier normally becomes the superior vena cava (Figure 1B). The fully developed superior vena caval system is demonstrated in Figure 2. If the left innominate vein fails to develop, the left anterior cardinal vein persists and continues to drain the left brachiocephalic veins. In this situation it becomes the left superior vena cava. Since the left duct of Cuvier empties into the left half of the sinus venosus which ultimately becomes the coronary sinus, a persistent left superior vena cava drains into this structure (Figure lB).’-3

During the course of parenteral nutrition in infants, access to the central venous system may become limited due to thrombotic occlusion of the superior and inferior caval venous systems. When this problem arises, central venous access via the intercostal vein into the azygos system can provide a safe, relatively easy solution. A new technique utilizing this approach has been developed at our institution using silicone elastomer tubing joined with a Broviac catheter for long-term use. Thus far, six catheters have successfully been inserted with a mean duration of 52 days; one catheter was in place for as long as 110 days.