Image Morphological Study Of Brachial Plexus And A Preliminary Research On Sectional Anatomy Of Normal Brachial Plexus And Lumbosacral Plexus And Visualization Of Their Main Structures In The VCH Female â… 

BackgroundThe precise preoperative clinical and electrophysiological evaluation of the brachial plexus as well as an exact radiological evaluation are the keystones for the treatment of traumatic injuries of the brachial plexus. Furthermore, surgical management and prognosis of traction injuries of the brachial plexus depend on the accurate diagnosis of root avulsion from the spinal cord. With the needing of non-traumatic or less-traumatic operation it is of great important to find a non-invasive method in the diagnostic of brachial plexus injury. Some modalities are available for obtaining images of the brachial plexus: computed tomography (CT), ultrasonography, myelography, and postmyelography CT (CTM) or magnetic resonance imaging (MRI). Both CT and MRI are commonly used to evaluate patients in the non-traumatic category of brachial plexopathy. MRI is superior because of its ability to directly visualize nerves and blood vessels, its good tissue contrast, its relative lack of artifact, and its multiplanar imaging capabilities. The major disadvantages of CT in the lower neck are that only direct axial images can be obtained and beam-hardening artifacts are encountered at the thoracic inlet. Myelography and CTM have been used for imaging both preganglionic andpostganglionic injury to the brachial plexus. One advantage of myelography is its ability to delineate the entire injury. Both techniques, however, involve considerable exposure to radiation and the possibility of reaction to the contrast medium. CTM is superior to conventional myelography in visualising the nerve rootlets because of axial imaging, but it is difficult to detect the entire extent of the injuries. The detection of partial or complete cervical root damage was not fully reliable in either myelography or CTM. Recently, As a non-invasive diagnostic tool, the usefulness of MRI for injury to the brachial plexus has been reported in a lot of literature, but the acquisition time for conventional MRI is long, and the injury is not always clearly visible. Furthermore, it is difficult to determine the entire extent of the injury with single axial MRI, as in CTM, and thus combinations of multiple slices or multiple planes are needed. At present, using continuous thin-layer MR Imaging to demonstrate the normal MR anatomy of the brachial plexus is a new research. Although CTM and MRI may detect avulsion of cervical nerve roots, but CTM is a invasive methods, and may appear artifacts in MR scanning because of breathing. These disadvantages could be resolved by ultrasonography. Also it has some technical limitations when compared with MR imaging, including the inability to track the roots inside the foramina, but ultrasonography could provides excellent nerve depiction and may be helpful in guidance of brachial nerve injuries. Because ultrasonography can reveal the level of the root of the brachial plexus on the basis of different morphologic characteristics on the vertebral landmarks. In 2D imaging methods, ultrasonography and MR imaging did not appear to be comparable with. But ultrasonography can revealed an enlarged, edematous trunk of the brachial plexus with loss of the hyperechoic lining, while magnetic resonance imaging showed only an edematous brachial plexus but did not reveal discontinuity of the nerve trunks.In recent years, a rapidly increasing portion of research in the field of medical image analysis has begun to focus on shape as an anatomical object property. Shape representations and shape models are being used in connection with: three-dimensional visualization of anatomical objects; segmentation of 3D medicalimages; diagnosis; surgical simulation; motion analysis and radiotherapy treatment planning. The desired properties of shape representations and shape models depend largely on the medical application to be supported. With the development of the computer technology, especially the technique of computer-assisted 3D reconstruction has been applied generally in the medical domain, which has the merit that three-dimensional anatomic structure can be observed from any angles and directions. In the medical science image, "Visible Human Project of America " (1989) has made a great response in the world. As the prelude of the virtual human study in China, supported by National "863" Development project of high-tech Research and National foundation for Outstanding Young Science, the first Military Medical University published serials research reported on "Virtual Chinese Human ". But nerve information is deficient in cross section tissue image of virtual human at present, there has not better counter measure in the display of peripheral nerve.Traumatic injuries of lumbosacral plexus are rare in clinic, unlike brachial plexus lesions, and are easily missed, especially in the multiply-injured patient. It has important instructional significance for the pathogenesis, diagnose and therapy of the injury of lumbosacral plexus to study the neuromechanism and adjacent relationship of lumbosacral plexus. And a good knowledge of these anatomic structures allows the surgeon to detect the injury of lumbosacral plexus safely in operation. So using the VCH dataset to model the main 3D lumbosacral plexus anatomy and its adjacent structures is another new research topic. Objectives1 . To demonstrate the mapping of the brachial plexus by means of high-resolution sonography.2. To demonstrate the normal MR anatomy of the brachial plexus by means of continuous thin-layer MR.3. To observe the normal structure of brachial plexus and lumbosacral plexus inthe VCH Female I and to establish their digitized visible models.Materials and methods1. Color Doppler Sonographic mapping of the normal brachial plexus: Eight healthy adult volunteers (three women and five men) underwent bilateral sonographic examination for the assessment of the nerve structures of the brachial plexus from the extraforaminal part to the axillary part. The extraforaminal and interscalenic parts of the cervical nerve roots were assessed first. Then, the nervous structures were explored at the junction between the interscalene triangle and the costoclavicular space by a supraclavicular approach, and the costoclavicular space by an infraclavicular approach. Finally, exploration of the retropectoralis minor tunnel part of the nerve structures was performed. Sonographic images were obtained with a high frequency linear transducer, 10 MHz. The musculotendinous, nerve, vascular, and bone structures were identified on anatomic sections according to the descriptions found in the literature and compared with the sonograms.2. Normal anatomy of brachial plexus with MR Imaging: Six healthy adult volunteers (two women and four men) underwent bilateral examination with a 1.5-T imager (GE, Signa) to assess the nerve structures of the brachial plexus. The FOV for coronal imaging the brachial plexus in Tl is 320mmx320mm, and a 256x224 matrix is used. Section thickness is 2mm, and a gap is 0.3mm. The FOV in oblique sagittal fat-suppressed T2-weighted image for imaging the brachial plexus is 200mmx200mm, and a 320x256 matrix is used. Section thickness is 2mm with contiguous images in oblique sagittal plane to obtain sufficient length of coverage.3. Sectional anatomy and visualization: The cross-sectional images of fresh tissues from the VCH Female I dataset were reviewed. VCH Female I dataset consisted of a total 8 556 images with an approximate data size of 150 G. The resolution are 3 024x2 016 pixels , 149.7 G in size, TIF format. Resolution are 180x120 pixels, 0.77 M in each image , JPG format. 527 serially-sectioned slices of VCH Female I including C4 and T2 were taken as a source of 3D models in brachial plexus study. 1491 serially-sectioned slices of VCH Female I including the middleof L3 and femur tuberositas were taken as a source of 3D models in lumbosacral plexus study. The main structures of the normal brachial plexus and lumbosacral plexus were studied on a section-by-section basis. The vertebral canal, spinal cord and blood vessels were also observed. Three-dimensional computerized reconstructions of brachial plexus and lumbosacral plexus and their adjacent structures were conducted from these data using Photoshop (Adobe) and Amira (TGS) imaging software. The software Photoshop and Amira were respectively adopted for 2D and 3D image processing. A technical route of reconstruction as followed: 1) Trace the outline of the main structure of brachial plexus and lumbosacral plexus in the 2-D imagery. 2) Triangulate between these contours on adjacent layers. 3) Create an overall mesh from all the pairs of contours. 4) And finally, render the structure from single nerves to regional anatomical structures , to finally the whole part. Results1. Color Doppler Sonographic mapping of the normal brachial plexus: A satisfactory sonographic examination was performed in all volunteers. The subclavian and deep cervical arteries were useful landmarks for this mapping. Sonography was also reliable in depicting the level of the C7 vertebra because of the absence of the anterior tubercle from its transverse processes.In each compartment, the nerve structures appeared as hypoechoic round to oval or trabs structures. Sonography of the brachial plexus began with recognition of the cervical roots in their extraforaminal part. In each volunteer, the C5, C& and C7 nerve roots were well visualized as they left the intervertebral foramina in a downward and outward direction. The C5 was found to be more oblique than the lower ones. The Cg and Ti nerve roots of the brachial plexus were more difficult to analyze because of their deep location. At the interscalene triangle, images were obtained in a sagittal plane. The interscalene triangle was well identified, bordered anteriorly by the anterior scalene muscle and posteriorly by the middle and posterior scalene muscles. In this space, the nerve structures appeared as oval hypoechoic structures arranged above the subclavian artery, which lies at the bottom of the interscalene triangle. Injunction between theinterscalene triangle and costoclavicular Space, the brachial plexus appeared as a triangular cluster of well-delineated round hypoechoic structures.In costoclavicular space the sonographic incidences allowed fairlyeasy identification of all three cords of the brachial plexus.Sonography allowed the cords of the brachial plexus to be visualized running parallel to the axillary vessels above and posterior to the axillary artery in each volunteer in space behind the pectoralis minor.2. Normal anatomy of brachial plexus with MR Imaging: Coronal and oblique —sagittal fat-suppressed T2-weighted image were performed in all volunteers. All brachial plexus were manifested, especially outlet of nerve root. T2-weighted images obtained in the oblique — sagittal plane clearly depicted the different compartments of brachial plexus.3. Sectional anatomy and visualization: The cross-sectional images of the VCH Female I could fairly display the main structure of brachial plexus and lumbosacral plexus, and also demonstrate osseous tissue, connective tissue, nerve and vessels. The three-dimensional reconstructed images could display perfectly the anatomic relationships of these structures. Statistical treatment results of sagittal and transverse diameters of C5~8 and Tl nerve roots are as follows: Sagittal diameters, C5 3.48±O.27(left) 2.26±0.68(right); C6 3.68±O.47(left) 3.18±O.61(right); C7 4.58±0.46(left) 4.10±0.69(right); C8 4.92±0.85(left) 4.56±O.87(right); Tl 4.22±1.01(left) 2.44±0.64(right). Transverse diameters, C5 2.35±0.15(left) 1.98±O.28(right); C6 3.28±O.48(left) 2.42±0.68(right) ; C7 2.77±0.47(left) 1.81±O.53(right) ; C8 3.51±0.81 (left) 2.91±O.72(right) ; Tl 2.60±0.44(left) 1.65±0.50(right). Statistical treatment results of sagittal and transverse diameters of vertebral canal and spinal cord at different outlet of cervical nerves roots are: Sagittal diameters of vertebral canal, 22.42±0.22(C5) 23.29±0.30(C6) 22.56±0.40(C7) 21.21±1.23(C8) 22.96±1.25(T1); Transverse diameters of vertebral canal, 13.40±0.14(C5) 12.75±0.18(C6) 12.42±0.29(C7) 14.16±0.42(C8) 14.31±O.64(T1); Sagittal diameters of spinal cord, 12.13±O.15(C5) 12.19±0.12(C6) 10.72±0.40(C7)9.12±0.28(C8) 9.67±O.46(T1); Transverse diameters of vertebral canal, 7.92±0.34(C5) 8.87±0.29(C6) 9.33±0.28(C7) 8.74±0.48(C8) 7.43±O.29(T1). Conclusions1. The brachial plexus can be mapped with high-resolution sonography, which may increase the rate of diagnostic of brachial plexus injury.2. MR imaging appears to be a useful techinique to study the anatomy brachial plexus because of its excellent soft-tissue depiction. It may have potential applications in the assessment of brachial plexus injury.3. The VCH Female I dataset can provide complete and accurate data of main structures of brachial plexus and lumbosacral plexus. The digitized model of brachial plexus and lumbosacral plexus offer unique insights into the complex anatomy, providing morphologic data for imaging diagnosis and treatment of the injury of brachial plexus and . lumbosacral plexus.