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Three-dimensional ultrasound (3D US) in small parts
Abstracts
Three-dimensional ultrasound (3D US) in small parts Fernandez LJ, Laboratorio de Ecografia Avanzada Vascular, Instituto Medico La Floresta, Caracas, DF, Venezuela, and Seccion de Ultrasonido Tridimensional, SonoImagen-JUREI Escuela Internacional de Ecografia, Caracas, DF, Venezuela 3D US is a recent technique in clinical practice, which has been mostly used in Obstetrics and Gynecology. Although there is relatively little experience in other areas, it is increasing day by day. There are different types of 3D US: vascular, volumetric, surface, multiplanar, niche mode, and VOCAL (virtual organ computer-aided analysis). The multiplanar, niche mode, and VOCAL are extremely useful because they help us define the anatomical relationships, identify the segments affected, and do a precise follow-up of oncological patients. The echo-tomography provides millimetric cuts of any structure, defining the precise limits of a lesion or eventual tumoral invasion to another segment or organ. The VOCAL is a very useful tool because it is able to automatically calculate the volume of a tumor. We can get an overall image of the small organs and focus on the vascularity organization. The assessment of small parts is properly achieved with 3D US. We can discriminate normal anatomical structures from pathological ones. The evidence of neovascularization is better viewed with 3D US and probably can suggest malignant origin of a neoplasm. Three-dimensional ultrasound is a new and outstanding technique that opens a new vision in diagnostic ultrasonography. It offers a more comprehensive image of anatomical structures and pathological conditions and also permits to observe the exact spatial relationships. New applications of 3D US are daily emerging, coming from the curiosity of many doctors from all over the world and from the necessity to assess the human body in an accurate and non-invasive approach.
Three-dimensional ultrasonography of the upper gastrointestinal tract Gilja OH, Medicine, Haukeland University Hospital, Bergen, Norway Three-dimensional (3D) ultrasonographic methods, which are strongly computer dependent, have evolved as a supplement to ordinary 2D ultrasound examinations. This lecture introduces some of the principles, methods, and clinical applications in 3D ultrasonography of the GI tract. Usually, the process of making 3D images based on ultrasonography is divided into 5 steps: data acquisition, data digitization, data storage, data processing, and data display. For volume estimation of organs and tumors, 2D methods are often based on geometrical assumptions, which introduce significant errors. Therefore, volume estimation based on 3D methods has been developed to increase accuracy and precision. For mapping of complex anatomy, e.g., to aid surgical planning, 3D ultrasonography appears to be a promising tool. 3D endosonography, in particular, may benefit from the increased level of standardization of acquisition, shortened scanning time, and possibility for detailed volume analysis with arbitrary slicing after the scanning procedure. However, there are limitations of 3D ultrasonography that need to be acknowledged. The whole process from acquisition to display of 3D images is usually time-consuming and requires dedicated, well-trained operators. The importance of high- quality raw data enabled by careful acquisition cannot be overestimated, as there is principally no new image data in the 3D file compared to the original 2D images. The future of 3D ultrasonography lies in development of real-time data acquisition and image rendering. Online display and volume calculation will enhance diagnostic value and allow smooth patient examination and workup. Further development of contrast agents may aid 3D automatic rendering and speed up volume estimation. Therefore, 3D ultrasonography may become not only an excellent diagnostic tool, but also an important imaging modality in interventional medicine.
S43
Three-dimensional ultrasound in rare gastrointestinal diseases (amyloidosis, intestinal lymphangiectasia, carcinoid) Szekely G, Gastroenterology, St. Janos Hospital, Budapest, Hungary 2D and color Doppler US is not able to give an exact localisation of the wall infiltration and the extension of gastrointestinal diseases. Digital 3D ultrasound technique makes possible the immediate spatial reconstruction of the opened investigation area. The data can be stored and analysed any time after the investigation. Patients with rare gastrointestinal diseases were examined by traditional 2D and 3D ultrasound methods. General complaints and symptoms were epigastric pain, palpable and painful abdominal mass, abdominal discomfort, diarrhoea, and rectal bleeding. In case of intestinal lymphangiectasia, slightly dilated small intestines with thickened jejunal and ileal folds and tortuous tubular structures were found. In case of amyloidosis, the segmental lack of peristalsis was seen. Carcinoid tumor of intestines can be rarely seen by transcutan ultrasound. In the follow-up of liver metastases of patients with carcinoid tumor, a hypoechoic mass and stenosis of the small intestine could be detected, which proved to be an intestinal recurrence. Endorectal 3D ultrasound is the imaging modality of choice for assessing submucosal tumors. The lesions can be visualized in different planes, which would have been impossible with conventional 2D imaging. In patients with rectal carcinoid tumors, the typical 3D US pattern corresponds to the histological findings. In case of solid tumor and liver metastases, volumetric and functional blood flow parameters can be obtained by 3D color and power Doppler methods. Sequential volumetric assays are accurate and repeatable and faster than 3D computer tomography. In conclusion, in case of rare GI diseases, 3D ultrasound gives important complimentary information about the extension, depth of infiltration, or invasion of the process.
MINIMALLY INVASIVE GYNECOLOGY AND THREEDIMENSIONAL ULTRASOUND Ultrasound-guided ablation of cervical and cornual ectopic pregnancies Doubilet P, Radiology, Brigham and Women’s Hospital, Boston, MA, and Radiology, Harvard Medical School, Boston, MA Cervical and cornual ectopic pregnancies are rare in pregnancies conceived naturally, but occur with greater frequency in pregnancies achieved via in vitro fertilization and other assisted reproductive techniques. Ultrasound permits diagnosis of these ectopic pregnancies early in gestation, which has led to minimally invasive, uterus-sparing, therapy. It is important to distinguish a cervical ectopic pregnancy from a spontaneous abortion-in-progress, which typically appears as an irregularly shaped sac in the cervix or lower uterine segment surrounded by a poor decidual reaction. Similarly, a cornual ectopic pregnancy must be distinguished from an eccentrically positioned intrauterine pregnancy (e.g., a pregnancy in one horn of a bicornuate uterus); the latter has normal-appearing myometrium surrounding the entire gestational sac, while the former has little or no myometrium surrounding the superolateral aspect of the sac. When the diagnosis of cervical or cornual ectopic pregnancy is established, ablation of the ectopic can be performed by guiding a needle into the gestational sac. For cervical ectopics, this is done using a transvaginal transducer with a needle guide, while for cornual ectopics it is done either transvaginally or transabdominally. If there is an embryo with a heartbeat, the needle is advanced into the embryo, and potassium chloride is injected until cardiac activity ceases. In the absence of an embryo or heartbeat, potassium chloride is instilled directly into the gestational sac. After injection, the sac progressively decreases in size, and the cervix or cornu returns to normal over the next few weeks.
Three-dimensional ultrasound (3D US) in small parts Fernandez LJ, Laboratorio de Ecografia Avanzada Vascular, Instituto Medico La Floresta, Caracas, DF, Venezuela, and Seccion de Ultrasonido Tridimensional, SonoImagen-JUREI Escuela Internacional de Ecografia, Caracas, DF, Venezuela 3D US is a recent technique in clinical practice, which has been mostly used in Obstetrics and Gynecology. Although there is relatively little experience in other areas, it is increasing day by day. There are different types of 3D US: vascular, volumetric, surface, multiplanar, niche mode, and VOCAL (virtual organ computer-aided analysis). The multiplanar, niche mode, and VOCAL are extremely useful because they help us define the anatomical relationships, identify the segments affected, and do a precise follow-up of oncological patients. The echo-tomography provides millimetric cuts of any structure, defining the precise limits of a lesion or eventual tumoral invasion to another segment or organ. The VOCAL is a very useful tool because it is able to automatically calculate the volume of a tumor. We can get an overall image of the small organs and focus on the vascularity organization. The assessment of small parts is properly achieved with 3D US. We can discriminate normal anatomical structures from pathological ones. The evidence of neovascularization is better viewed with 3D US and probably can suggest malignant origin of a neoplasm. Three-dimensional ultrasound is a new and outstanding technique that opens a new vision in diagnostic ultrasonography. It offers a more comprehensive image of anatomical structures and pathological conditions and also permits to observe the exact spatial relationships. New applications of 3D US are daily emerging, coming from the curiosity of many doctors from all over the world and from the necessity to assess the human body in an accurate and non-invasive approach.
Three-dimensional ultrasonography of the upper gastrointestinal tract Gilja OH, Medicine, Haukeland University Hospital, Bergen, Norway Three-dimensional (3D) ultrasonographic methods, which are strongly computer dependent, have evolved as a supplement to ordinary 2D ultrasound examinations. This lecture introduces some of the principles, methods, and clinical applications in 3D ultrasonography of the GI tract. Usually, the process of making 3D images based on ultrasonography is divided into 5 steps: data acquisition, data digitization, data storage, data processing, and data display. For volume estimation of organs and tumors, 2D methods are often based on geometrical assumptions, which introduce significant errors. Therefore, volume estimation based on 3D methods has been developed to increase accuracy and precision. For mapping of complex anatomy, e.g., to aid surgical planning, 3D ultrasonography appears to be a promising tool. 3D endosonography, in particular, may benefit from the increased level of standardization of acquisition, shortened scanning time, and possibility for detailed volume analysis with arbitrary slicing after the scanning procedure. However, there are limitations of 3D ultrasonography that need to be acknowledged. The whole process from acquisition to display of 3D images is usually time-consuming and requires dedicated, well-trained operators. The importance of high- quality raw data enabled by careful acquisition cannot be overestimated, as there is principally no new image data in the 3D file compared to the original 2D images. The future of 3D ultrasonography lies in development of real-time data acquisition and image rendering. Online display and volume calculation will enhance diagnostic value and allow smooth patient examination and workup. Further development of contrast agents may aid 3D automatic rendering and speed up volume estimation. Therefore, 3D ultrasonography may become not only an excellent diagnostic tool, but also an important imaging modality in interventional medicine.
S43
Three-dimensional ultrasound in rare gastrointestinal diseases (amyloidosis, intestinal lymphangiectasia, carcinoid) Szekely G, Gastroenterology, St. Janos Hospital, Budapest, Hungary 2D and color Doppler US is not able to give an exact localisation of the wall infiltration and the extension of gastrointestinal diseases. Digital 3D ultrasound technique makes possible the immediate spatial reconstruction of the opened investigation area. The data can be stored and analysed any time after the investigation. Patients with rare gastrointestinal diseases were examined by traditional 2D and 3D ultrasound methods. General complaints and symptoms were epigastric pain, palpable and painful abdominal mass, abdominal discomfort, diarrhoea, and rectal bleeding. In case of intestinal lymphangiectasia, slightly dilated small intestines with thickened jejunal and ileal folds and tortuous tubular structures were found. In case of amyloidosis, the segmental lack of peristalsis was seen. Carcinoid tumor of intestines can be rarely seen by transcutan ultrasound. In the follow-up of liver metastases of patients with carcinoid tumor, a hypoechoic mass and stenosis of the small intestine could be detected, which proved to be an intestinal recurrence. Endorectal 3D ultrasound is the imaging modality of choice for assessing submucosal tumors. The lesions can be visualized in different planes, which would have been impossible with conventional 2D imaging. In patients with rectal carcinoid tumors, the typical 3D US pattern corresponds to the histological findings. In case of solid tumor and liver metastases, volumetric and functional blood flow parameters can be obtained by 3D color and power Doppler methods. Sequential volumetric assays are accurate and repeatable and faster than 3D computer tomography. In conclusion, in case of rare GI diseases, 3D ultrasound gives important complimentary information about the extension, depth of infiltration, or invasion of the process.
MINIMALLY INVASIVE GYNECOLOGY AND THREEDIMENSIONAL ULTRASOUND Ultrasound-guided ablation of cervical and cornual ectopic pregnancies Doubilet P, Radiology, Brigham and Women’s Hospital, Boston, MA, and Radiology, Harvard Medical School, Boston, MA Cervical and cornual ectopic pregnancies are rare in pregnancies conceived naturally, but occur with greater frequency in pregnancies achieved via in vitro fertilization and other assisted reproductive techniques. Ultrasound permits diagnosis of these ectopic pregnancies early in gestation, which has led to minimally invasive, uterus-sparing, therapy. It is important to distinguish a cervical ectopic pregnancy from a spontaneous abortion-in-progress, which typically appears as an irregularly shaped sac in the cervix or lower uterine segment surrounded by a poor decidual reaction. Similarly, a cornual ectopic pregnancy must be distinguished from an eccentrically positioned intrauterine pregnancy (e.g., a pregnancy in one horn of a bicornuate uterus); the latter has normal-appearing myometrium surrounding the entire gestational sac, while the former has little or no myometrium surrounding the superolateral aspect of the sac. When the diagnosis of cervical or cornual ectopic pregnancy is established, ablation of the ectopic can be performed by guiding a needle into the gestational sac. For cervical ectopics, this is done using a transvaginal transducer with a needle guide, while for cornual ectopics it is done either transvaginally or transabdominally. If there is an embryo with a heartbeat, the needle is advanced into the embryo, and potassium chloride is injected until cardiac activity ceases. In the absence of an embryo or heartbeat, potassium chloride is instilled directly into the gestational sac. After injection, the sac progressively decreases in size, and the cervix or cornu returns to normal over the next few weeks.