Abdomen and pelvis radiography in practise .ptx

Abdominal xray

1. Positioning in Abdomen and pelvis radiography Dr. Kirti Vibhuute

2. Learning objectives – Abdomen Urinary tract (KUB) Urinary bladder Biliary system

3. Extention - Superiorly from the inferior surface of the diaphragm Inferiorly - to the pelvic inlet inferiorly Laterally - contained by the muscles of the abdominal walls. Divided into nine regions by two transverse planes and two parasagittal (or vertical) planes. The upper transverse plane ( transpyloric plane) is midway between the suprasternal notch and the symphysis pubis – approximately midway between the upper border of the xiphisternum and the umbilicus. Posteriorly - through the body of the 1st lumbar vertebra near its lower border Anteriorly - passes through the tips of the right and left 9th costal cartilages and also through the level of the pylorus of the stomach. Abdomen

4. The lower transverse plane ( transtubercular plane) Anteriorly - at the level of the tubercles of the iliac crest and Posteriorly - near the upper border of the 5th lumbar vertebra. The two parasagittal planes are at right-angles to the two transverse planes. They run vertically passing through a point midway between the anterior superior iliac spine and the symphysis pubis on each side, in the mid-clavicular line. These planes divide the abdomen into nine regions centrally f rom above to below epigastric, umbilical and hypogastric regions and laterally from above to below right and left hypochondriac, lumbar and iliac regions. The pelvic cavity is continuous with the abdominal cavity at the pelvic inlet, extends inferiorly to the muscles of the pelvic floor and is contained within the bony pelvis.

5. Indications - • Obstruction of the bowel. • Perforation. • Renal pathology. • Acute abdomen (with no clear clinical diagnosis). • Foreign body localization . • Toxic mega colon. • Aortic aneurysm. • Prior to the introduction of a contrast medium(scout film) e.g. intravenous urography (IVU) to demonstrate the presence of radio-opaque renal or gall stones and to assess the adequacy of bowel preparation, if used. • To detect calcification or abnormal gas collections, e.g. abscess. • Alimentary studies using barium preparations.

6. Recommended projections Examination is performed by means of the following: Basic • Antero- poste rior – supine Alternative • Postero –anterior – prone Supplementary • Antero-posterior – erect • Antero-posterior or Postero -anterior – left lateral decubitus • Lateral – dorsal decubitus • Posterior obliques

7. Radiography is normally performed using a standard imaging table with a moving grid. However, depending on the condition of the patient imaging may be performed on a trauma trolley with computed radiography (CR) cassettes or a mobile direct digital radiography (DDR) detector using a stationary grid . Focal spot size - ≤ 1.3 mm Total filtration - 1.3 mm Al equivalent Anti-scatter grid - R=10; n=40/cm FRD - 115 (100–150) cm Radiographic voltage - 75–90 kV Automatic exposure control Chamber selected. MAs – 30 -120 ma s

8. Essential image characteristics Coverage – Superiorly - Diaphragm Inferiorly - Inferior to the symphysis pubis Laterally - Pro-peritoneal fat stripe. Reproduction of the whole of the urinary tract (kidneys– ureters–bladder [KUB]). Demonstration of the kidney outlines. High resolution of the bones. Adequate contrast to demonstrate the interface between air-filled bowel and surrounding soft tissues. Radiation protection • The exclusion of pregnancy via the 28/10 day rules should be observed. • Gonad shielding can be used for males.

9. Antero-posterior – supine A table Bucky DDR system is employed or alternatively a CR cassette is selected. Position of patient and image receptor • Position - supine with the median sagittal plane at right-angles and coincident with the midline of the table. • The pelvis is adjusted so that the anterior superior iliac spines are equidistant from the tabletop. • Cassette - 35 × 43 cm and is placed longitudinally in the cassette tray and positioned so that the region below the symphysis pubis is included on the lower margin of the image. • Centering – at the level of a point located 1 cm below the line joining the iliac crests.

10. Direction and location of the X-ray beam The collimated vertical beam is directed to the center of the image receptor to include the lateral margins of the abdomen. Using a short exposure time, the exposure is made on arrested respiration. Ideally respiration should be arrested on full expiration to allow the abdominal contents to lie in their natural position.

11. Common faults and solutions • Failure to include the region inferior to the symphysis pubis and the diaphragm on the same image. (in bariatric patients) • Failure to visualise the lateral extent of the abdominal cavity including the lateral peritoneal fat stripe ( due to patient size or poor positioning) • Respiratory movement unsharpness ( reduced by rehearsal of the arrested breathing technique prior to exposure) • Rotation may be evident when the patient is in pain. • Underexposure may be caused by patient size or incorrect selection of AECs. • Presence of artefacts such as buttons or contents of pockets if the patient remains clothed for the examination.

12. Antero-posterior – erect The patient is examined standing or seated against a vertical Bucky, or alternatively may be examined on a tilting table with a C-arm using a large image DDR detector/ X-ray tube assembly. If necessary the patient may be examined sitting on a trolley or on a chair using a stationary grid with a 35 × 43 cm CR cassette; however, the resulting image resolution may be compromised.

13. Patient positioning – Position - stands / sits with their back against the receptor . If standing the patient’s legs are placed well apart so that a comfortable and steady position is adopted. If seated care must be taken to ensure the flexed knees are not obscuring the lower abdomen. Centering - midpoint between the xiphisternum and umbilicus. Direction and location of the X-ray beam - • The collimated horizontal beam is directed so that it is coincident with the center of the receptor in the midline. • An exposure is taken on normal full expiration.

14. Antero-posterior – left lateral decubitus It is used if the patient cannot be positioned erect - to confirm the presence of subdiaphragmatic gas. With the patient lying on the left side, free gas will rise to be located between the lateral margin of the liver and the right lateral abdominal wall. To allow time for the gas to collect , the patient should remain lying on the left side for a short while (e.g. 10 minutes) before the exposure is made.

15. Direction and location of X-ray beam • The collimated horizontal central beam is directed to the anterior aspect of the patient and centerd to the center of the image receptor. Position of patient and image receptor • Patient position - on their left side with the elbows and arms flexed so that the hands can rest near the patient’s head. • With the posterior aspect of the trunk against a vertical Bucky coverage - upper border of the image receptor high enough to project above the right lateral abdominal and thoracic walls. Cassette - 35 × 43 cm CR. Vertically against the patient’s side • The patient’s position is adjusted to bring the median sagittal plane at right-angles to the image receptor.

16. Occasionally the patient is unable to sit or even be rolled on to their side, thus the patient remains supine and a lateral projection is taken using a horizontal central ray. Position of patient and image receptor Patient position - supine with the arms raised away from the abdomen and thorax. Cassette - 35 × 43 cm CR. Vertically against the patient’s side Collimation - the thorax to the level of mid sternum and as much of the abdomen as possible. Care should be taken that the anterior wall of the trunk is not projected off the resultant image. Direction and location of the X-ray beam • The collimated horizontal central beam is directed to the lateral aspect of the trunk at right-angles to the receptor. Lateral – dorsal decubitus (supine)

17. It is undertaken to visualize - • The outline of the kidneys surrounded by their perirenal fat. • The lateral border of the psoas muscles. • Opaque stones in the kidney area, in the line of the ureters and in the region of the bladder. • Calcifications within the kidney or within the bladder. • The presence of gas within the urinary tract. • Any other acute abdominal pathology. Urinary tract – kidneys– ureters–bladder

18. Preparation of the patient Bladder should be empty. A low residue diet during the 48 hours prior to the examination to clear the bowel of gas and faecal matter that might overlie the renal tract. In the case of emergency radiography no bowel preparation is possible. The patient is undressed and wears a gown.

19. Position of patient and image receptor • Position of patient - supine with the median sagittal plane of the body at right-angles to and in the midline of the table. • Hands placed high on the chest or the arms may rest by the patient’s side slightly away from the trunk. • collimation - Above the upper poles of the kidneys to the symphysis pubis. • The image receptor is positioned so that the symphysis pubis is included on the lower part of the image. Casette - 35 x 43 cm . Longitudinally in bucky tray • The centering - approximately at the level of a point located 1 cm below the line joining the iliac crests. Antero-posterior supine

20. Direction and location of the X-ray beam • The vertical collimated beam is directed to the center of the image receptor with the lateral margins collimated within the margins of the image receptor. • The exposure is made on arrested expiration

21. Position of patient and image receptor • Patient position - supine with the median sagittal plane of the body at right-angles to and in the midline of the table. • Collimation - above the upper poles of the kidneys to the region included superiorly on the incomplete KUB image. • Cassette/receptor - transversely in the Bucky tray . Centered - to a level midway between the xiphoid–sternum and iliac crests. Direction and location of the X-ray beam • The collimated vertical central ray is directed to the centre of the image receptor AP cross table kidney radiograph

22. Position of patient and image receptor • Patient position - supine and then the left side of the trunk and thorax is raised at an angle of 15–20° to the table. • The patient is moved across the X-ray table until the vertebral column is slightly to the left side of the midline and then the patient is immobilised in this position, possibly using radio-opaque pads. • Cassette size - 24 × 30 cm is placed transversely in the Bucky tray. Centred - midway between the sterno-xiphisternal joint and umbilicus. • To demonstrate the length of the ureter a 35 × 43 cm cassette might be required and this is centred at the level of the lower costal margin. Direction and location of the X-ray beam • The collimated vertical central ray is directed to the centre of the image receptor/cassette Right and left posterior oblique

23. Position of patient and image receptor • Patient position - Supine with the median sagittal plane at right-angles to, and in the midline of the table. • Cassette size - 24 × 30 cm CR; and placed transversely in the tray with its lower border 5 cm below the symphysis pubis. Direction and location of the X-ray beam. • The collimated central ray is directed 15° caudally . Centering - in the midline 5 cm above the upper border of the symphysis pubis. (e.g. midway between the anterior superior iliac spines and upper border of the symphysis pubis). Antero-posterior 15° caudal Urinary bladder

24. Right or left posterior oblique Position of patient and image receptor • Position - Supine position one side is raised so that the median sagittal plane is rotated through 35°. • The knee in contact with the table is flexed and the raised side supported using a non-opaque pad. • Centering - midpoint between the symphysis pubis and the anterior superior iliac spine on the raised side is over the midline of the table/receptor. • Cassette size - 24 × 30 cm CR is placed longitudinally in the tray with its upper border at the level of the anterior superior iliac spines.

25. Direction and location of the X-ray beam • The collimated vertical central beam is directed to a point in the midline 2.5 cm above the symphysis pubis. • Alternatively a caudal angulation of 15° can be used with a higher centring point and the receptor displaced downwards to accommodate the angulation and allow for better demonstration of the apex of the bladder.

26. The Biliary system

27. Left anterior oblique The size of the CR cassette, if chosen, is such that a large region of the right side of the abdomen is included. Position of patient and image receptor • Patient position - prone with the right side is raised rotating the median sagittal plane through an angle of 20°. • The arm on the raised side is flexed so that the right hand rests near the patient’s head, while the left arm lies alongside and behind the trunk. • The patient is moved across the table until the raised right side is over the centre of the table. • Cassette - A 24 × 30 cm. Longitudinally in the Bucky tray. Centre - 2.5 cm above the lower costal margin.

28. Direction and location of the X-ray beam • The collimated vertical central ray is directed to a point 7.5 cm to the right of the spinous processes 2.5 cm above the lower costal margin the centre of the image receptor. • The exposure is made on arrested respiration after full expiration

29. Right posterior oblique Position of patient and image receptor • Patient position - supine and the left side is raised through 20° and the trunk supported in this position using a non-opaque pad. • The patient is moved across the table so that the right side of the abdomen is over the centre of the table, and the elbows and shoulders flexed so that the patient can rest their hands under their head. • Cassette - A 24 × 30 cm and placed longitudinally in the Bucky tray. Centre - 2.5 cm above the lower costal margin. Direction and location of the X-ray beam • Directed to a point midway between the midline and the right abdominal wall 2.5 cm above the lower costal margin. • Exposure is made on arrested respiration after full expiration

30. Air in the biliary tree

31. Thank you…