CN102151141A - Method for measuring femoral head-neck spatial angles - Google Patents

Abstract

The invention relates to a measurement method of CT scanning and post-processing, and aims to provide a measurement method of a three-dimensional femoral head and neck space angle. The present invention is achieved through the following steps: the person to be measured lies on his back on the examination bed, and the midsagittal line of the human body coincides with the midline of the examination bed; using multi-layer spiral CT scanning, continuous data acquisition is performed on the human body to obtain a thin layer sequence, and the scanning range is above To the upper edge of the acetabulum, including the lesser trochanter of the femur; use the three-dimensional post-processing program to reconstruct the three-dimensional image of the hip joint with the thin-slice sequence, remove irrelevant structures such as the acetabulum, and obtain a three-dimensional image of the femur; perform femoral head camber, retroversion and Measurement of downtilt. The characteristics of the technical solution are: the three-dimensionally reconstructed femoral surface anatomical structure is clearly displayed, the position is easy to adjust, and the spatial angle of the femoral head and neck can be accurately measured.

Description

Measuring method of space angle of femoral head and neck

technical field

The invention relates to a measurement method of CT scanning and post-processing, in particular to a method for measuring the spatial angle of the femoral head and neck by using a three-dimensional post-processing image.

Background technique

The measurement of the space angle of the femoral head and neck has a guiding role in the reduction of femoral head and neck fractures and the manufacture and installation of artificial hip joints, and has very important clinical significance.

Nowadays, the measurement of human femoral space angle is mainly through CT method and bare bone projection measurement method (hereinafter referred to as "bare bone method"). The typical CT method is to place the specimen flat on the scanning bed, and measure the femoral head and neck perpendicular to the long axis of the femur. and femoral condyle level for two-dimensional scanning. The typical bare-bone method is to place the femoral specimen on a horizontal plane, the posterior edge of the two condyles and the posterior edge of the greater trochanter are in contact with the horizontal surface, the camera is placed at the same height as the femoral shaft, and the axial projection shows that the posterior edge of the greater trochanter touches the point of imaging. Located between the points of contact between the posterior borders of the two condyles. The acquired images are then measured. The specific image measurement methods include the measurement of the retroversion angle of the femoral neck, etc., including the Murphy method (the angle between the axis of the femoral head neck and the axis of the femoral condyle) and the Hernandez method (the angle between the axis of the transverse section of the femoral neck and the axis of the femoral condyle). wait.

The method for measuring the spatial angle of the femur in the above scheme has the following disadvantages: it is all measured on two-dimensional images, and it is difficult to intuitively measure various spatial angles of the femur, and the final generated image is also a two-dimensional image, which cannot be intuitively measured. Observation of various spatial angle states of the femur.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for measuring the space angle of the three-dimensional femoral head and neck, which can accurately measure the spatial state of the femoral head and neck in the human skeleton.

The object of the present invention can be achieved through the following steps:

(1) Place the human bone specimen including the femur on the scanning table, with the midsagittal line of the human body parallel to the midline of the examination table;

(2) CT scan: use multi-slice spiral CT scan to continuously collect data on the human body to obtain thin-slice sequences. The scan range includes the upper edge of the acetabulum and the lower trochanter of the femur;

(3) Three-dimensional reconstruction: use the three-dimensional post-processing program to reconstruct the three-dimensional image of the hip joint with the thin-slice sequence, remove irrelevant structures such as the acetabulum, and obtain a three-dimensional image of the femoral head and neck;

(4) For the obtained femoral three-dimensional image, carry out the measurement of femoral head and neck camber angle, retroversion angle and inclination angle: described femoral three-dimensional image is set as positive position, determines femoral head and neck central axis, and described femoral head and neck central axis is in the middle of the body The included angle of the sagittal line is the camber angle of the femoral head and neck, and the included angle between the central axis of the femoral head and neck and the horizontal transverse line of the body is the downward inclination of the femoral head and neck; The femurs on both sides are basically coincident, and the central axis of the femoral head and neck is determined. The included angle between the central axis of the femoral head and neck and the coronal line in the center of the body is the retroversion angle of the femoral head and neck, and the included angle between the central axis of the femoral head and the horizontal transverse line of the body is is the downtilt angle of the femoral head and neck; the three-dimensional image of the femur is set as the axial position, and the central axis of the femoral head and neck is determined.

In the above solution, in the anterior view, lateral view and axial view of the femur, it is only necessary to select the anterior view plus the lateral view or the positive view plus the axial view to accurately measure the three-dimensional space angle of the femoral head and neck.

The characteristics of the above-mentioned technical solution are: the anatomical structure of the femoral surface of the three-dimensional reconstruction is clearly displayed, and the position can be adjusted by rotation, and the spatial angle of the femur can be clearly displayed. The data can be collected quickly and conveniently, and the measured data can be fully utilized in fields such as prosthetic limb shaping.

Further: in the step (4), the line connecting the center of the femoral head fitting circle and the midpoint of the short axis of the femoral neck is the central axis of the femoral neck, and the short axis of the femoral neck is the line connecting the narrowest part of the femoral neck . . This is a more accurate measurement method for measuring the midline of the femoral head and neck.

Further: in the step (4), the line connecting the midpoint of the femoral head arc and the midpoint of the shortest diameter of the femoral neck is the central axis of the femoral head and neck, and the short axis of the femoral neck is the line connecting the narrowest part of the femoral neck, It is a relatively simple and reliable method of measuring the midline of the femoral head and neck.

Description of drawings

Below in conjunction with accompanying drawing and specific embodiment the present invention will be described in further detail:

Fig. 1 is the positive position schematic diagram of measuring femoral head camber and downtilt in the embodiment of the present invention;

Fig. 2 is the axial schematic diagram of measuring femoral head neck recoil angle in the embodiment of the present invention;

Fig. 3 is a lateral schematic diagram of measuring the retroversion and downtilt angles of the femoral head and neck in the embodiment of the present invention.

Detailed ways

The known structures and methods in this solution will not be described here. Follow the steps below:

(1) Place the complete human skeleton specimen on the scanning table in a normal state, with the midsagittal line of the human body parallel to the midline of the examination table.

(2) CT scanning: use multi-slice spiral CT scanning to continuously collect data on the human body to obtain thin-slice sequences. The scanning parameters are 120KV and 150MAS, the slice thickness is 1 mm, and the interval is 0.6 mm. The scanning range is from the upper edge of the acetabulum to the lower to the lesser trochanter of the femur.

(3) Three-dimensional reconstruction: using a three-dimensional post-processing program to reconstruct a three-dimensional image of the hip joint from the thin-slice sequence, removing irrelevant structures such as the acetabulum, and obtaining a three-dimensional image of the femur.

(4) The three-dimensional image of the femur obtained carries out the following measurements: the three-dimensional image of the femur obtained carries out the measurement of camber, retroversion and inclination: the three-dimensional image of the femur is set as the positive position, and the femoral head is fitted to make a circle 11, and then Make a line segment 12 coincident with the short axis of the femoral neck, connect the center of the circle 11 and the midpoint of the line segment 12 to make a straight line 13, and the gained straight line 13 is the femoral head and neck central axis, measure the femoral head and neck central axis and the mid-sagittal line of the body The included angle 14 of 4, the included angle 14 is the camber angle of the femoral head and neck, the included angle between the central axis of the femoral head and neck and the horizontal transverse line of the body is the downward inclination of the femoral head and neck; The three-dimensional observation angle makes the both sides of the femur be at the same level, fit the femoral head to make a circle 21, make a line segment 22 coincident with the short axis of the femoral neck, connect the center of the circle 21 and the midpoint of the line segment 22 to obtain the femoral head-neck axis 23, The included angle 24 of the central axis 23 of the femoral head neck and the middle coronal line 5 of the body is the retroversion angle of the femoral head neck; the three-dimensional image of the femur is set as the lateral position, and the fitting femoral head is used as a circle 31, and the line segment 32 coincident with the short axis of the femoral neck , connect the center of the circle 31 and the midpoint of the line segment 32 to obtain the central axis 33 of the femoral head and neck, and the included angle between the central axis of the femoral head and neck 33 and the centerline coronal line 5 of the body is the retroversion angle 34 of the femoral head and neck. The angle between the horizontal transverse lines of the body is the downward inclination of the femoral head and neck.

What has been described above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, some deformations and improvements can be made without departing from the present invention, such as changing the determination of the central axis of the femoral head and neck Mode: determined by the connection line between the midpoint of the femoral head arc and the midpoint of the shortest diameter of the femoral neck, these should also be regarded as the protection scope of the present invention, and these will not affect the effect of the present invention's implementation and the practicability of the patent.

Claims (3)

1. The measuring method of femoral head and neck space angle, its step comprises: (1) Place the human bone specimen including the femur on the scanning table, with the midsagittal line of the human body parallel to the midline of the examination table; (2) CT scan: use multi-slice spiral CT scan to continuously collect data on the human body to obtain thin-slice sequences. The scan range includes the upper edge of the acetabulum and the lower trochanter of the femur; (3) Three-dimensional reconstruction: use the three-dimensional post-processing program to reconstruct the three-dimensional image of the hip joint with the thin-slice sequence, remove irrelevant structures such as the acetabulum, and obtain a three-dimensional image of the femoral head and neck; (4) For the obtained femoral three-dimensional image, carry out the measurement of femoral head and neck camber angle, retroversion angle and inclination angle: described femoral three-dimensional image is set as positive position, determines femoral head and neck central axis, and described femoral head and neck central axis is in the middle of the body The included angle of the sagittal line is the camber angle of the femoral head and neck, and the included angle of the central axis of the femoral head and neck and the horizontal transverse line of the body is the downward inclination of the femoral head and neck; The three-dimensional image of the femur is set as the lateral position, the three-dimensional observation angle is adjusted so that the femurs on both sides are basically coincident, and the central axis of the femoral head and neck is determined. The angle between the central axis of the femoral head and neck and the horizontal transverse line of the body is the downward inclination of the femoral head and neck; The three-dimensional image of the femur is set as the axial position, and the central axis of the femoral head and neck is determined. The angle between the central axis of the femoral head and neck and the coronal line of the body center is the retroversion angle of the femoral head and neck. 2. the measuring method of femoral head and neck space angle according to claim 1, is characterized in that: in described step (4), the connecting line of the center of circle of femoral head fitting circle and femoral neck minor axis midpoint is femoral head and neck central axis. 3. the measuring method of femoral head and neck space angle according to claim 1 is characterized in that: in described step (4), the line connecting femoral head arc midpoint and femoral neck shortest diameter midpoint is femoral head and neck center axis.

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