Abdomen Anatomy and Positioning (RADS 220)

Bony Abdomen consists of:

-pelvis

- lower vertebral column

*lumbar

*sacrum/coccyx

iliac crest

upper curved border of the ilium

anterior superior iliac spine (ASIS)

is anterior to the iliac crest; a bony prominent projection

symphysis pubis

Anterior junction of the 2 pubic bones of pelvis.

greater trochanter of femur

the most superior portion of this prominence; lies the level of symphysis pubis

ischial tuberosity

bears the weight when one sits, lies 1in below pubis

psoas muscle

normally seen in the posterior walls of the abdomen, fan shapped, L1-L5

Diaphragm

separates abdominal from thoracic cavity, one on each side (hemidiaphragms)

-erect abdomen or center 2in above iliac crest

The abdomen is divided into 4 quadrants by a

line drawn transversely through abdomen at the level of the umbilicus and longitudinally through MSP

-RUQ,LUQ,RLQ,LLQ

Abdominal Aortic Aneurysm (AAA)

Aneurysm located in the abdominal aorta.

ascites

collection of fluid within spaces of the abdomen

bowel obstruction

blockage of small intestine or large intestine

ileus

small bowel obstruction

metastasis

spread of cancer to abdominal organs

Pneumoperitoneum

Free air in the abdominal cavity

tumor

mass or swelling within the abdomen

Preparation for Abdomen X-Ray in nonacute conditions

-controlled diet

-laxative

-enemas

never done to ill patients

Abdomen procedures kVp

80-85 to obtain maximum soft tissue differentiation throughout the different abdominal regions

Exposure time for abdomen procedures

1/2 second or less to block any visceral peristalsis (motion)

mAs for abdomen has to be sufficient for

optimum IRE or exposure index

Immobilization for Abdomen Procedures

adjust patient in comfortable position, so patient can relax and prevents muscle contractions caused by tension

-explain breathing procedure, make sure patient has stopped breathing

Focal Spot used for Abdomen Procedures

Large Focal Spot to reduce heat load on xray tube

For all abdominal radiographs, you should be able to differentiate the following

-psoas muscle

-kidneys

-lower margin of the liver

-transverse process of the lumbar spine

-ribs

Gonadal Shielding is required in the following situations: (Abdomen)

-if gonads lie in close proximity (2in) to the primary xray despite proper beam limitation

-the the objectives of the exam will not be obscured or compromised

-if patient has reasonable reproductive potential

Should you do AP or PA for abdomen procedure?

PA whenever possible because it produces less scatter and reduces dose to ovaries

Abdomen procedure may also be called

KUB, Supine abdomen, AP abdomen

KUB

kidneys, ureters, bladder

Light size for Abdomen Procedures

14 x 17

SID for all abdomen projections

40 in

Supine Abdomen (KUB) position

MSP centered to the midline, arms at sides, legs uncrossed,

CR for Supine Abdomen (KUB)

Center to top of iliac crests and midline, directed perpendicular to midpoint of IR

-include pubic symphysis

Tall patients may require

2 radiographs ;'(14x17 & 10 x12)

Structures shown for Supine Abdomen (KUB)

-size and shape of liver, spleen, and kidneys

-any calcifications or tumor masses within abdominal cavity

Evaluation Criteria for Supine Abdomen

-includes symphysis

-upper margin of kidneys

-spine in center

-no rotation

-lateral collimation should be visible

-soft tissue gray tones

AP Upright/ Erect Abdomen includes the

diaphragm

AP Upright/ Erect Abdomen is used to check for

-air fluid levels

-movement of abdominal organs

-obstruction

-drainage of ureters in IVU examinations

CR for AP Uright/ Erect Abdomen

perpendicular to IR to enter the patient at a transverse level of 2 in above the iliac crest or high enough to include diaphragm

SS for AP upright/ erect abdomen

show size and shape of liver, spleen, kidneys, abdominal masses, air fluid levels, accumulation of gas or free intra abdominal air

EC for AP uright/erect abdomen

no rotation, vertebral column aligned to center of the radiograph, should visualize lateral collimation, R or L marker at bottom, -diaphragms included as well as cosmopolis angles and lateral margins of abdomen

Left Lateral Decubitus Abdomen

want to include diaphragm so we center at a level 2 in above iliac crest

How long should a patient lie on the left side for a LLD of the abdomen?

5 minutes minimum for larger amounts of gas to allow fee air to rise

-10-20 minutes for small gas

Why do we do a left lateral decubitus over a right lateral decubitus for the abdomen?

it allows air to escape readily from most common sites of perforation

-air will rise under liver, which because of its solidity will contrast the air

-it also would be difficult to distinguish free air from the air in the fundus of the stomach

A right lateral decubitus for the abdomen is only requested if

the patient cannot lie on the left side

For a Semi-erect abdomen you elevate the table

75-80 degrees

CR for Semi-erect abdomen

directed horizontally (parallel with floor) to midpoint of IR

For Semi-erect abdomen we want to include the

diaphragm so we center CR 2 in above the iliac crest

SS for Semi-erect abdomen

distorted view of abdomen & shows air fluid levels

R or L dorsal decubitus abdomen position

patient is supine with affected side in contact with the vertical IR; elevate patient on a sponge

CR for R or L dorsal decubitus abdomen

horizontal and perpendicular to the midcoronal plane and at the level 2 in above iliac crest

SS for R or L dorsal decubitus abdomen

demonstrates the pre vertebral space and air fluid levels in the abdomen

EC for R or L dorsal decubitus abdomen

diaphragm without motion, collimation soft tissue gray tones of the abdomen elevate patient so that entire abdominal contents are demonstrated

Purpose of Acute Abdominal Series

-Free air

-Obstruction

-Infection

-Intra-abdominal mas

-Post op (after surgery)

3 way abdomen series

AP supine, AP erect, PA chest

2-way abdomen series

AP supine and AP upright

-"flat & erect abdomen"