Radiographic Techniques Lecture 6: Lumbar Vertebrae PDF

Radiographic Techniques Lec 6 Lumbar vertebrae BY AHMED JASEM ABASS MSC of Medical Imaging 1  Position of patient and image receptor  The patient lies supine on the Bucky table, with the median sagittal plane coincident with, and at right-angles to, the midline of the ta...

Radiographic Techniques Lec 6 Lumbar vertebrae BY AHMED JASEM ABASS MSC of Medical Imaging 1  Position of patient and image receptor  The patient lies supine on the Bucky table, with the median sagittal plane coincident with, and at right-angles to, the midline of the table and Bucky.  The anterior superior iliac spines should be equidistant from the tabletop.  The hips and knees are flexed and the feet are placed with their plantar aspect on the tabletop to reduce the lumbar arch and bring the lumbar region of the vertebral column parallel with the image receptor.  CR cassette should be large enough to include the lower thoracic vertebrae and the sacro-iliac joints and is centred at the level of the lower costal margin.  The exposure should be made on arrested expiration, as expiration will cause the diaphragm to move superiorly. The air within the lungs would otherwise cause a large difference in density and poor contrast between the upper and lower lumbar vertebrae. 2  Essential image characteristics (Figs 6.21c, 6.21d)  The image should include from T12 down, and sacro-iliac joints.  Rotation can be assessed by ensuring that the sacro-iliac joints are equidistant from the spine.  The exposure used should produce a density such that bony detail can be discerned throughout the region of interest.  Common faults and solutions  The most common fault is to miss some or all of the sacroiliac joint. An  additional projection of the sacro-iliac joints should be performed. 3 4  Position of patient and image receptor  The patient lies on either side on the Bucky table.  The arms should be raised and resting on the pillow in front of the patient’s head.  The knees and hips are flexed for stability.  The coronal plane running through the centre of the spine should coincide with, and be perpendicular to, the midline of the Bucky.  Non-opaque pads may be placed under the waist and knees, as necessary, to bring the vertebral column parallel to the image receptor.  The image receptor is centred at the level of the lower costal margin.  The exposure should be made on arrested expiration.  This projection can also be undertaken erect with the patient standing or sitting. 5  Direction and location of the X-ray beam  The collimated vertical beam is centred at right-angles to the line of spinous processes anterior to the 3rd lumbar spinous process at the level of the lower costal margin  Essential image characteristics (Fig. 6.22c)  The image should include T12 downwards, to include the lumbar sacral junction.  The posterior and anterior margins of the vertebral body should also be superimposed.  The imaging factors selected must produce an image density sufficient for diagnosis from T12 to L5/S1, including the spinous processes. 6  Common faults and solutions(Figs 6.23c, 6.23d)  High-contrast images will result in an insufficient or high image density over areas, software application is recommended.  The spinous processes can easily be excluded from the image as a result of collimation.  Poor superimposition of the anterior and posterior margins of the vertebral bodies is an indication that the patient was rolled too far forward or backward during the initial positioning (i.e. mean sagittal plane not parallel to receptor).  Failure to demonstrate a clear intervertebral disc space usually results as a consequence of the spine not being perfectly parallel with the receptor or is due to scoliosis or other patient pathology. 7 8  Lateral projections in flexion and extension may be requested to demonstrate mobility and stability of the lumbar vertebrae. 9  Position of patient and image receptor  This projection may be performed supine, but it is most commonly performed erect with the patient seated on a stool with either side against the vertical Bucky.  For the first exposure the patient leans forward, flexing the lumbar region as far as possible, and grips the front of the seat to assist in maintaining the position.  For the second exposure the patient then leans backward, extending the lumbar region as far as possible, and grips the back of the seat or another support placed behind the patient.  The Bucky is centred at the level of the lower costal margin, and the exposure is made on arrested expiration. 10  Direction and location of the X-ray beam  The collimated horizontal beam is directed at right- angles to the image receptor and centred anterior to the 3rd lumbar spinous process at the level of the lower costal margin. 11  Essential image characteristics (Figs 6.25c, 6.25d)  All of the area of interest must be included on both projections.  A short exposure time is desirable, as it is difficult for the patient to remain stable. 12  AP Axial  Position of patient and image receptor  The patient lies supine on the Bucky table, with the median sagittal plane coincident with, and at right-angles to, the midline of the Bucky.  No rotation of pelvis (ASIS the same distance from tabletop)  Direction and location of the X-ray beam  The collimated vertical beam is directed cephalad (5cm) below level of ASIS 13 14