Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
  • A61B6/48—Diagnostic techniques
  • A61B6/481—Diagnostic techniques involving the use of contrast agents
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
  • A61B6/50—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment specially adapted for specific body parts; specially adapted for specific clinical applications
  • A61B6/504—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment specially adapted for specific body parts; specially adapted for specific clinical applications for diagnosis of blood vessels, e.g. by angiography
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
  • A61B6/54—Control of apparatus or devices for radiation diagnosis
  • A61B6/548—Remote control of the apparatus or devices

Definitions

• the invention relates to a method according to the preamble of claim 1 and an apparatus for performing the method.
• contrast medium-filled vessel sections For examining the vessels of a larger body section, e.g. of a leg, it is known to record contrast medium-filled vessel sections by means of conventional x-ray images. After the contrast medium has been injected into the vascular system via a catheter, the contrast medium gradually reaches the extremity periphery due to the systemic blood pressure , X-rays are taken according to the flow rate of the contrast medium.
• a disadvantage of this method which is referred to as conventional sheet film angiography, is above all that a high contrast agent concentration must be present in the vascular sections of interest in order to obtain high-contrast X-ray images of the vessels despite the X-ray absorption caused by soft tissue and bones.
• the lee mask is subtracted from each fill image. Only the image of the section of the vessel filled with contrast medium remains. The subtraction images are simultaneously transferred to the examiner on an image monitor.
• a low contrast agent concentration in the vascular section shown is sufficient and, in addition to arterial administration, allows the contrast agent to be injected into a suitable vein, as a result of which the contrast agent enters the arterial vascular system via the small circulation.
• the invention is based on the object of developing a method of the type mentioned at the outset such that high-contrast images of successive vessel sections are obtained in a short time with low contrast medium consumption.
• digitally processed empty images are made (for example for the representation of the vessels of a leg) starting from the distally relevant vessel section (foot) to the proximally interested vessel section (bifts), without contrast medium being present in the vessel sections of interest.
• Contrast agent injection at the appropriate point in time then floods the contrast agent in the proximal vascular section (hifts).
• the step-by-step relative movement between the patient and the X-ray unit in exactly the same positions in which empty masks were previously recorded allows the outflow of contrast medium to be traced distally (to the foot) and the fillings to be obtained. These are also recorded and saved in digital form.
• the image processor assigns the empty masks of the individual sections to the filling images of the same position, obtained in one recording process, and subtracts them in such a way that high-contrast subtraction images of only the vessels through which contrast medium flows are obtained from each recording position.
• the subtraction images are also recorded and stored digitally.
• Fillings immediately receive subtraction images of the individual vascular sections and can, for example, monitor the successive recordings and thus the contrast agent outflow on a monitor.
• the sequence of empty masks is automatically or preprogrammed in such a way that step-by-step recordings of successive sections of the area to be examined are made successively by a relative movement between the X-ray unit and the patient.
• the sequence of fillings can also be made automatically or preprogrammed according to the expected flow rate of the contrast medium in the vessels.
• the drawing shows schematically a table 1 and an X-ray unit 2, the table and the X-ray unit being movable relative to one another step by step by a control device such that the individual positions relative to one another can be assumed exactly again.
• a relative displacement in two mutually perpendicular, horizontal directions is provided for detecting the course of the vessel.
• the height of the X-ray table and of the X-ray tube and image intensifier receiving unit can be adjusted relative to one another.
• Table 1 is moved relative to the X-ray unit 2 by a drive device, not shown.
• a vessel section of approximately 30 cm corresponding to the acquisition region of the image intensifier reception unit is recorded, as indicated by broken lines, which is followed immediately by the following section after a corresponding relative shift.
• the individual images can overlap somewhat in the edge area.
• the recordings are converted into digital signals in a unit 3, which are sent to one unit. are passed on, in which each image is stored with assignment to the respective image position and processed by an image processor in the subtraction process.
• a separate memory or a correspondingly large memory for several recordings can be provided for each recording.
• a monitoring system (not shown) with a monitor can be connected to the device. The device is designed so that the displacement of the table or the X-ray unit is carried out without vibration.
• X-ray dose values including a suitable superimposition of the X-rays, can be assigned to the individual exposure positions to the particular body section to be examined. These parameters and the number and direction of the relative displacements can be primarily programmed in a standard program or can be individually adapted to the patient to be examined before the actual recording process. Known aids such as e.g. X-ray absorbers (rice flour sacks) can be used.
• the recorded images can be processed using known post-processing methods, e.g. Pixel shift can be prepared.
• the recordings can be taken in close succession in the described method, there is a short examination time combined with a correspondingly low radiation exposure of the patient.
• the radiation exposure of the examiner can be further reduced by controlling the device by means of monitor monitoring outside the examination room.
• the required amount and concentration of contrast medium can be kept low for the single injection.
• the method succeeds in obtaining high-contrast X-ray images of the examined vascular sections with a low contrast agent consumption and correspondingly low exposure of the patient to the potentially dose-dependent toxic contrast agent.
• the invention can also be used to check technical line systems and is not limited to angiography.

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• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Medical Informatics (AREA)
• Engineering & Computer Science (AREA)
• Radiology & Medical Imaging (AREA)
• Molecular Biology (AREA)
• Biophysics (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Optics & Photonics (AREA)
• Pathology (AREA)
• Physics & Mathematics (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• High Energy & Nuclear Physics (AREA)
• Surgery (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Vascular Medicine (AREA)
• Dentistry (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Apparatus For Radiation Diagnosis (AREA)

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Citations (2)

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• 1989
  • 1989-06-14 DE DE19893919473 patent/DE3919473C1/de not_active Expired - Lifetime
• 1990
  • 1990-06-13 WO PCT/EP1990/000932 patent/WO1990015574A1/de unknown

Patent Citations (2)

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