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Venous structures

Since this technique relies on detecting the highest pixel on a given ray, it is sensitive to overlap from adjacent bony and opacified venous structures, as shown in Fig. 4.12. Currently, attempts are being made to subtract the underlying bony structures, but to date these have been limited by multiple technical factors, not least of which is subtle patient motion resulting in inaccurate representation of the composite image. [Pg.69]

Soyer P, Heath D, Bluemke DA et al (1996c) Three-dimensional helical CT of intrahepatic venous structures comparison of three rendering techniques. JCAT 20 122-127... [Pg.292]

Fig.4.16a-c. Typical signs of intracranial dural arteriovenous malformation (DAVM) by CT. a Ectatic venous structure and hydrocephalus, b Multiple enhancing vascular structures following contrast administration, representing draining veins, c Dilated subarachnoid spaces due to cortical atrophy... [Pg.142]

The axillary vein is a large venous structure that represents the continuation of the basilic vein. It starts at the lower border of the teres major tendon and... [Pg.122]

Fig. 4.4 Detailed anatomy of the neck demonstrating the relationship of the venous structures, and superficial and deep anatomy. (From Belott PH, Reynolds DW. Permanent pacemaker and cardioverter defibrillation implantation. In EUenbogen KA, Kay N, Wilkoff BL, eds. Clinical cardiac pacing and defihrillation, 2nd ed. Philadelphia WB Saunders, 2000, with permission.)... Fig. 4.4 Detailed anatomy of the neck demonstrating the relationship of the venous structures, and superficial and deep anatomy. (From Belott PH, Reynolds DW. Permanent pacemaker and cardioverter defibrillation implantation. In EUenbogen KA, Kay N, Wilkoff BL, eds. Clinical cardiac pacing and defihrillation, 2nd ed. Philadelphia WB Saunders, 2000, with permission.)...
Table 4.9 Venous structures for pacemaker lead insertion. Cephalic vein Axillary vein Subclavian vein Internal jugular vein... Table 4.9 Venous structures for pacemaker lead insertion. Cephalic vein Axillary vein Subclavian vein Internal jugular vein...
Once again, it is important for the operator to be completely familiar with normal anatomy and superficial anatomic landmarks. The traditional subclavian puncture is carried out in the middle third of the clavicle. This location is frequently associated with an increased risk of vascular trauma, pneumothorax, and a lack of success. An alternate approach calls for the puncture at the apex of an angle formed by the clavicle and first rib (Fig. 4.11) (57). This location is remote from the apex of the lung, and the venous structure is generally much larger. [Pg.129]

The jugular vein has been used for permanent pacemaker implantation as an alternate cutdown site (81). As a rule, the jugular vein has not been utilized for nonthoracotomy lead systems. This is a large venous structure that lies in the cervical triangle defined by the lateral border of the omohyoid muscle, inferior... [Pg.144]

Venous access can be carried out by either cutdown or the percutaneous approach. If the initial electrode has been placed via cutdown, the isolation of a second vein for venous access will prove extremely difficult. In this case, percutaneous approach should be attempted. Conversely, if the initial electrode has been placed percutaneously, then a second percutaneous approach or a cut-down is always possible. The second percutaneous puncture is usually carried out just lateral to the initial venous entry site. The initial lead can be used as a marker of the venous anatomy. If any difficulty is encountered, fluoroscopy is used to guide the lead using the chronic ventricular lead for reference (85,86). There is potential risk of damaging the initial electrode and care should be taken to avoid its direct puncture. The use of radiographic materials can also help define the venous structure as well as its patency. [Pg.150]

The Curry Wire Loop Snare is generally reserved for retrieval of a lead that has a free end (43). These are usually lead remnants that are free-floating in the venous structures, right atrium, and right ventricle. The fundamental... [Pg.291]

Another approach is the placement of a catheter in the subclavian vein via the femoral vein, which may be used to perform a radiographic contrast injection for outlining the venous structures, and may also be left as a target for subclavian needle entry. The catheter is advanced far laterally to the junction between the subclavian and axillary veins, and the use of this as a target allows for a very lateral entry and thereby avoids the problem of subclavian crush injury to the leads (41). The use of such a catheter for angiograms will also identify venous abnormalities, such as a persistent left superior vena cava prior to creation of the pacemaker pocket. [Pg.556]

Neville et al. 1994). Overall, experimental studies showed that venous structure and hemodynamics were compatible with endoluminal stent placement. [Pg.116]

The reference vein actually needs to be the pixel with the largest area under its contrast-enhancement curve. As such, it must be selected at the center of the largest vascular structure perpendicular to the PCT slices. These requirements are usually met by pixels at the center of the superior sagittal sinus. However, in some instances, other venous structures, or even the su-praclinoid internal carotid arteries, can be appropriate veins for PCT processing purposes. [Pg.113]

In solid organs such as the liver, major iatrogenic bleeding is sometimes due to communication between the tract and a major venous structure. Arteriography will usually not reveal any abnormality nor provide an access for therapy. In most cases of venous bleeding, simply leaving the drainage cath-... [Pg.84]

Fig. 12. Anterior coronal plane of the right hippocampal-hippocampus complex with relationship to neighbouring structures. Demonstration of important arterial and venous structures. Green line pia, hlac line arachnoidea. Drawing modified after Salamon and Huang, Fig. 171, page 225... Fig. 12. Anterior coronal plane of the right hippocampal-hippocampus complex with relationship to neighbouring structures. Demonstration of important arterial and venous structures. Green line pia, hlac line arachnoidea. Drawing modified after Salamon and Huang, Fig. 171, page 225...

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