RAD 451 Abdomen and Pelvis CT (1) By the end of the lecture students should be able to: State the common indications for Abdomen and pelvis CT exams Identify possible contra indications for Abdomen and Pelvis exams Explain the general and specific patient preparation for Abdomen and pelvis CT exams Recognize the contrast medium types,volume and route of administration for abdomen and pelvis CT exams Interpret normal anatomical structures on sectional CT images. 1
References 1. Lois Romans Computed Tomography for Technologists: A Comprehensive Text, Lippincott Williams & Wilkins, ISBN: 9780781777513 2. Protocols for Multislice Helical Computed Tomography, The fundamentals. by Peter Dawson 3. Text book of radiographic positioning and related anatomy; by Kenneth L.Bontrager,8 th edition. http://www.unmc.edu/dissection/radiology/ http://www.ctisus.com/ http://www.slaney.org/pct/ http://w-radiology.com/index.html 3 Pathologic indications: Inflammatory diseases such as:- Pancreatitis, Appendicitis Inflammations of colon (e.g. Diverticulitis) Abscesses in the abdomen Primary and secondary tumors Staging for cancer Plan for radiation treatments for tumors Guide biopsies Vascular disorders Prostatic, cervix, urinary bladder and ovarian carcinoma. Soft tissue masses and diseases of the pelvic muscles. 2
Pathologic indications: Contrast Medium 1. Oral contrast 2. Intravenous 3. Rectal 3
Contrast Media (Oral contrast) Type:- Water-soluble contrast (e.g. Gastrografin) (5% CM+ 95% water) Thin barium sulphate suspension (e.g., Liquibar CT) or (Volume, E Z EM). With just 0.1% barium sulphate Conventional radiography barium suspension cannot be used in CT. (Because it produce unacceptable streak artifacts) Barium should not be given if perforation of the GIT is suspected. Barium leaking into the peritoneal cavity Volume:- 600-800 ml Timing:- The patient drink 400 600 over 45 min to 1 hour. The last 100-200 ml immediately before the starting of the exam Contrast Media (IV contrast) Type:- LOCM (e.g. Omnipaque) Volume:- 100-150 ml ( 2ml/Kg body weight for children Timing:- Bolus injection or with specific timing as needed 4
Contrast Media (Rectal contrast) Type:- Water-soluble agents (e.g. Gastrografin): dilute (5% CM+ 95% water) Thin barium sulphate suspension (e.g., Liquibar CT) Volume:- 150 to 200 ml Timing:- Just before starting the scan If enema is contra indicated 500 ml of oral contrast is advised night before the scan to opacify the large bowel Contrast Media (Others) Water:- Water is sometimes used in place of positive contrast agents. As a negative (or neutral) agent, water will not obscure mucosal surfaces, or superimpose abdominal vessels on three-dimensional images. water transits quite rapidly and distends the bowel poorly. Air and Carbon Dioxide:- Used to produce a very high negative contrast on images of the gastrointestinal tract. Negative contrast agents are particularly useful in CT Colonography when adequate colonic distension is critical for polyp detection. Room air is delivered using a standard handheld air bulb Carbon dioxide is delivered using an automated insufflation system 5
Patient preparation General:- Review of patient data:- Check the patient ID Clinical History Patient ability to cooperate Previous radiology exams (Any recent barium study??) Patient preparation General:- Psychological preparation Assure the patient with Briefing about the exam Answer patient questions Check for additional help Dress preparation (Gown) Radition Protection Check of pregnancy for female patients of child birth bearing (Apply 10 day rule) 6
Patient preparation Specific:- Bowel Preparattion For lower abdomen and pelvis CT as needed How?? Preparation for contrast adminstration Check for patient allergies to medications, or food Any previous reactions to contrast media Asthma and kidney problems Kidney function prior to CM injection Signing the contrast dye, consent Fasting 4-6 hours before the examination Patient preparation Preparation for contrast administration Who is at risk for an anaphylactic reaction? Patients with a prior history of contrast reaction Patients with a history asthma Patients with multiple environmental allergies, i.e. foods, hay fever, medications Considerations in patients with renal insufficiency Is the exam necessary? Is there an alternative exam that can answer the question? Decrease contrast dose 7
CT Attenuation Measures Hyper attenuating =(hyper dense) Hypo attenuating =(hypo dense) Iso attenuating = (Iso dense) Certain factors may interfere with the accuracy of CT scan of the abdomen. These factors include : Metallic objects within the abdomen, such as surgical clips Residual barium in the intestines from a recent barium study Stool and/or gas in the bowel Protocol Variables Protocol Type Plain or contrast enhanced Contrast administration and Timing Slice positioning Slice thickness Slice orientation Reconstruction algorithm Radiation dosimetry 16 8
Optimization of the CT examination Requires: Sufficient clinical information about the case from the referring physician The Technologist should select the appropriate CT protocol based on careful review of relevant patient history and clinical indications as well as all prior available imaging studies. 17 Abdomen and Pelvis Cross Sectional Anatomy https://www.youtube.com/watch?v=p_x_bbjnlu8 9
1. Right lung 2. Right hepatic vein. 3. Liver. 4. Left hepatic vein. 5. Stomach 6. Left splenic flexure 7. Spleen 8. Left lung. 9. Aorta. 1. Right lung 2. Aorta. 3. Left lung. 4. Left adrenal 5. Spleen 6. Splenic artery. 7. Colon. 8. Portal vein. 9. Hepatic vein. 10.Liver. 10
1. Diaphragm 2. Aorta. 3. Left Adrenal 4. Top of L. Kidney 5. Spleen 6. Splenic artery. 7. Colon. 8. Stomach 9. Portal vein. 10.Liver. 11. Rib 1. Inferior vena cava 2. Liver 3. Right Adrenal 4. Diaphragmatic crus 5. Abdominal Aorta 6. Left Adrenal 7. Left Kidney 8. Spleen 9. Pancreas 10.Colon 11
1. Inferior vena cava 2. Top of L. Kidney 3. Abdominal Aorta 4. Celiac truncus 5. Left Kidney 6. Colon 7. Splenic vein 8. Pancreas 9. Portal vein 1. Inferior vena cava 2. Right Kidney 3. Abdominal Aorta 4. S. mesenteric artery 5. Left Kidney 6. Small bowel 7. Colon 8. Portal vein 9. Liver 12
1. Inferior vena cava 2. Right Kidney 3. Aorta 4. Left renal vein 5. Left Kidney 6. S. mesenteric artery 7. S. mesenteric vein 8. Gallbladder 9. Liver 1. Inferior vena cava 2. Right Kidney 3. Origin of Rt. Renal A 4. Aorta 5. Left Kidney 6. Left colon 7. S. mesenteric artery 8. S. mesenteric vein 9. Gallbladder 10.Liver 13
1. Inferior vena cava 2. Right Kidney 3. Aorta 4. Left Kidney 5. Left colon 6. S. mesenteric artery 7. S. mesenteric vein 8. Gallbladder 9. Liver 1. Gallbladder 2. Liver 3. Inferior vena Cava 4. Right kidney 5. Aorta 6. Left kidney 7. Left colon 8. S. mesenteric artery 9. S. mesenteric vein 14
1. Transverse colon 2. Rectus abdominis M 3. Gallbladder 4. Liver 5. Right kidney 6. Inferior vena cava 7. Aorta 8. Left kidney 9. Left colon 1. Transverse colon 2. Liver 3. Right kidney 4. Inferior vena cava 5. Aorta 6. Lt. Kidney lower pole 7. Left colon 8. Rectus abdominis M 15
1. Rectus abdominis M 2. Colon 3. Liver 4. Right kidney 5. Inferior vena cava 6. Psoas muscle 7. Aorta 8. Lt. Kidney lower pole 9. Left colon 10.External oblique M 11.Internal oblique M 12.Transverse Abd M 1. Rectus abdominis M 2. Liver 3. Right kidney 4. Inferior vena cava 5. Spinal canal 6. Aorta 7. External oblique M 8. Internal oblique M 9. Transverse Abd M 10. Small intestine 16
1. Rectus abdominis M 2. Liver 3. Rt. kidney inferior pole 4. Vertebral body 5. Spinous process 6. Intervertebral foramina 7. External oblique M 8. Internal oblique M 9. Transverse Abd M 10. Small intestine 1. Small bowel 2. Colon 3. Liver 4. Inferior vena cava 5. Psoas muscle 6. Aorta 7. External oblique M 8. Internal oblique M 9. Transverse Abd M 10.Rectus abdominis M 17
Coronal 1. Heart 2. Right lung 3. Liver 4. Gallbladder 5. Colon 6. Rib 7. Left lung Coronal 1. Right lung 2. Liver 3. Gallbladder 4. Caecum 5. Bladder 6. Heart 7. Stomach 8. Colon 9. Small bowel 10.Sigmoid colon 18
Coronal 1. Right lung 2. Portal vein 3. Liver 4. Caecum 5. Bladder 6. Sigmoid colon 7. Small bowel 8. Colon 9. Heart Coronal 1. Right lung 2. Portal vein 3. Liver 4. Right colon 5. Bladder 6. Sigmoid colon 7. Small bowel 8. S. mesenteric vein 9. Heart 19
Coronal 1. Right lung 2. Liver 3. Hepatic vein 4. Portal vein 5. Right colon 6. Bladder 7. Heart 8. Stomach 9. Small bowel 10.Left colon Coronal 1. Heart 2. Stomach 3. Small bowel 4. Left colon 5. Lt. superficial femoral artery 6. Lt. superficial femoral vein 7. Pubic symphysis 8. Bladder 9. Right colon 10.Right kidney 11.Liver 12.Hepatic vein 13.Right lung 20
Coronal 1. Left lung 2. Colic tumor 3. External oblique muscle 4. Internal oblique muscle 5. T. abdominal muscle 6. Bladder 7. Pubic symphysis 8. Aorta 9. Inferior vena cava 10.Right kidney 11.Liver 12.Heart Coronal 1. Heart 2. Right kidney 3. Colic tumor 4. Psoas muscle 5. Iliac wing 6. Rectum 7. Bladder 8. Muscle gluteus medius 9. Muscle gluteus minimus 10.Right kidney 11.Liver 12.Right lung 21
Coronal 1. Left lung 2. Left colon 3. Left kidney 4. Psoas muscle 5. Acetabulum 6. Obturator internus muscle 7. Obturator externus muscle 8. Gluteus medius muscle 9. Gluteus minimus muscle 10.Right kidney 11.Liver 12.Aorta 13.Right lung Coronal 1. Aorta 2. Spleen 3. Left kidney 4. Psoas muscle 5. Ilium 6. Greater trochanter 7. Lesser trochanter 8. Anal canal 9. Rectum 10.Lumbar spine 11.Liver 12.Right lung 13.Right lung 22
Sagittal 1. Left lung 2. Spleen 3. Left kidney 4. Iliac wing 5. Gluteus maximus muscle 6. Iliac muscle 7. Rectus abdominis muscle 8. Small bowel 9. Colon 10.Heart Sagittal 1. Left lung 2. Spleen 3. Left kidney 4. Psoas muscle 5. Femoral head 6. Acetabulum 7. Colon 8. Heart 9. Stomach 10.Liver 11.Heart 23
Sagittal 1. Left lung 2. Spleen 3. Stomach 4. Left kidney 5. Psoas muscle 6. Rectus abdominis muscle 7. Small bowel 8. Colon 9. Liver 10.Heart Sagittal 1. Aorta 2. Vertebral body L2 3. Spinous process 4. Intervertebral disc L4-L5 5. Sacrum 6. Rectum 7. Bladder 8. Liver 9. Heart 24
Sagittal 1. Vertebral body T9 2. Spinous process 3. Aorta 4. Vertebral body L1 5. Intervertebral disc L2-L3 6. Sacrum 7. Rectum 8. Bladder 9. Small bowel 10.Hepatic vein 11.Liver 12.Heart 25