Three-dimensional spiral CT venography for the pre-operative assessment of varicose patients.

BACKGROUND: The purpose of pre-operative spiral CT venography or veno-CT (VCT) is to provide a precise 3D anatomic depiction of the venous network, to be used as a guideline by the surgeon. METHODS: A multislice and multidetector spiral CT acquisition of the lower limb with diluted contrast injection produces about 400 slices in 30 s. Dedicated volume-rendering software compute interactive 3D images of the venous system. Dynamic data are easily exported by e-mail and available for phlebologists and surgeons. As VCT provides no hemodynamic data, an associated color-coded duplex is mandatory. RESULTS: VCT is useful in case of post-operative recurrence (especially of the popliteal fossa), high or dystrophic termination of the short saphenous vein, varices feeded by the Giacomini vein, and to investigate pelvic or pudental varicose veins. A full knowledge of the complex venous networks is possible thanks to interactivity of the resulting 3D model, using rotation and modification of transparency of the tissues. CONCLUSION: Providing a more complete anatomical information, VCT makes possible a better surgical choice of technique, avoiding anatomic pitfalls, with a more precise and limited skin approach. Accordingly, it may hopefully improve the aesthetic result as well as the efficacy, by reducing the varicose veins recurrence rate.

The origin of the azygos venous system, as deduced from an anatomical and radiological study employing a corrosion technique.

The aim of this study is not only to describe the origin of the human azygos venous system by performing a 3-D reconstruction of a CT scan but also to evaluate the value of the techniques employed in investigating the topographical anatomy of a venous system in the body. Following perfusion with saline to wash away the blood, we injected an ALTUFIX/MINIUM mixture into the azygos vein of a cadaver. The head and trunk were subsequently corroded with hydrochloric acid (HCl). A CT scan of the trunk was obtained both before and after corrosion. According to the spatial resolution of the CT scan, the thinnest identifiable detail was measurable as 0.5 mm. The vertebral lumbar venous system was described, specifying the nomenclature of the lumbar veins (the lumbar veins being designated according to the vertebral body along which they run). On the right side, the lumbar veins at L2 and at L3 formed the lateral root of the azygos vein. On the left side, the vein at L2 formed the reno-azygo-lumbar arch (of Lejars). The lumbar veins, and the origin of the azygos system, were described and compared with previous studies. The 3-D reconstruction showed the importance of veins associated with the posterior paravertebral muscles. This description poses the problem of the metamerisation of the veins, but further evidence is required. Comparisons of the CT scans, 3-D reconstructions, and the ALTUFIX models of the veins obtained from the corrosion technique allowed verification of the 3-D reconstruction and correction of the errors inherent in a computer reconstruction. It is concluded that the description, and understanding, of such a complex system as the vertebral venous system is more valid when the results obtained using different techniques are compared.

[The lumbar vein at L2 and the reno-azygo-lumbar arch: anatomic and radiologic studies]. / La veine lombaire en L2 et l'arc réno-azygo-lombaire: étude anatomique et radiologique.

The lumbar vein at L2 was described by C. Gillot and B. Singer (1974). On the right side, after drawing off the 12th intercostal vein, it forms the lateral root of the azygos vein. Its way is as a frame, transverse going along the body of the 2nd lumbar vertebra, then upward along the spine after having integrated the veins of the L2-L3 intervertebral foramen. In its typical form, the vein is at L2 but it can be at L1 or L3. It takes the name of lateral root of the azygos vein only after receiving the 12th intercostal vein. Because of its diameter (5 mm), it forms a cavo-caval anastomosis via the azygos vein. The renal azygo-lumbar arch of Lejars is the equivalent on the left side of the right vein at L2. This arch contributes to the formation of the lateral root of the hemi-azygos vein. The right vein at L2 and the reno-azygo-lumbar arch were studied by dissections and by radiologic protocols. The radiologic studies (CT, MRI, 3D reconstructions) were carried out after injections of gelatin-gadolinium-minimum and altufix-minimum mixtures. The results showed the numerous variations of origin of the azygos system. The use of multiple and complementary technics are very helpful to describe these variations.

[Three-dimensional CT study of the carpus under pronation-supination constraints]. / Etude du carpe au scanner à trois dimensions sous contraintes de prono-supination.

By studying 3D imaging of the wrist under pronation-supination strain, we found that the simple comparison of a series of two corresponding cuts may provide a great deal of useful information on how the carpus transmits the longitudinal torque from the forearm to the hand. A special wooden trestle was made to fix the subject in the CT scanner in a permanent effort of pronation or supination. In the first group of scans, this effort was said to be "free" because the hand was simply maintained in a fixed window without any muscular contraction, except pronation or supination muscles. In the second group of scans, this effort was said to be "constrained" because the hand gripped a fixed bar with contraction of the flexor muscles. The thickness of the cuts was 1.2 millimeters and they were separated by 1.5 millimeters. Four levels were specially studied: the lower radio-ulnar joint (LRUJ), the proximal row of the carpus, the distal one and the metacarpal bases. Many elementary movements occur in the carpus in constrained supination: the triquetrum "supinates" (7 degrees), the scaphoid flattens and "pronates" (2 degrees) around the capitum the ridges of the carpal anterior concavity approximate (3 mm). In constrained pronation, the anterior concavity of the carpus flattens emphasizing the role of the anterior retinaculum. The LRUJ is very unstable: in free pronation, the ulnar head moves dorsally, firmly pressing the posterior part of the sigmoid notch, responsible for fracture of a postero-medial fragment in Colles fracture. The quadratus pronatus is a very important muscle to coapt this joint. We propose the "screwing (or unscrewing) test" in the diagnosis of arthrosis or instability of the LRUJ. We define the notion of "rotational shift" to appreciate the quality of the pronation/supination torque transmission. In constrained pronation/supination, this rotational shift is 5 degrees in the radio-carpal joint. This is very important to appreciate the quality of the wrist prosthesis. In free pronation/supination, the rotational shift is 45 degrees between radius and metacarpal bases. In constrained pronation/supination, it becomes 10 degrees. The wrist ligaments are unable to resist the wrist rotational shift and favor the torque transmission. The tendinous caging of the wrist is the main factor for maintaining rigidity of the carpus and transmitting the torque as muscles are contracted. The wrist can be compared with a fluid drive clutch, whose pedal is muscular contraction.

Agenesis of the left internal carotid artery associated with coarctation of the aorta: report on an unusual case.

An unusual association of agenesis of the left internal carotid artery and coarctation of the aorta is reported. There was also an aneurysm of the thoracic aorta distal to the coarctation. The subclavian artery was obstructed and revascularization occurred through the vertebral artery via anastomoses with the occipital artery. An embryological hypothesis for this association is proposed.