Agenda CT Contrast Media Weena Swatdiswanee Factorinvolvein contrast enchancement Senior Application Specialist, CT Regional Headquarter Asia Australia weena.swat@siemens.com Page 1 Page 2 Agenda Contrast Media Definition A medical contrast medium is a substance which is used to improve natural differences in densities between the structures of the human body in medical imaging Factor involvein contrast enchancement Contrast media makes the image more assessable Page 3 Page 4 Agenda Factor involvein contrast enchancement Page 5 Page 6 Handzettel 1
Agenda What kind of contrast media that we use in CT? Factor involvein contrast enchancement Radiolucent Negative / Neutral contrast agent Absorb less x-ray Appear dark on the image Air /CO 2 Radiopaque Positive contrast agent Absorb more x-ray Appear white on the image Iodine, Barium, Gastrograpfin Page 7 Page 8 What kind of contrast media that we use in CT? What kind of contrast media that we use in CT? Positive contrast media Positive contrast media Page 9 Page 10 What kind of contrast media that we use in CT? What kind of contrast media that we use in CT? Negative/ Neutral contrast media Page 11 Page 12 Handzettel 2
CT image with contrast media What kind of contrast media that we use in CT? Contrast medium: Categories Differences in iodinated contrast medium: Monomeric Dimeric Ionic Non Ionic Low Osmolar Contrast Medium High Osmolar Contrast Medium Iso-Osmolar Contrast Medium Page 13 Page 14 Contrast medium: Structure I Contrast medium: Chemistry Page 15 Page 16 Contrast medium: Chemistry Contrast medium: Reactions I Page 17 Page 18 Handzettel 3
Agenda Factor involvein contrast enchancement What do you HAVE TO CHECK to avoid patients damage? Prevention is always better Ask for any allergies Check if the patient takes Metformin (diabetics= Lactic acidosis) Check the blood value of kidneys Creatinin ( max.1.5) egfr* ( >60) ( new 45) *Estimated Glomerular Filtration Rate Page 19 Page 20 Agenda What to do in an Emergency? Factor involvein contrast enchancement Call your Emergency unit! Medication Cortisone ( Prednisolon) H1,H2 ( Antihistamine e.g.fenistill, Tagamed) Oxygen i.v. fluid ( NaCl) Page 21 Page 22 Agenda Factors involved in Contrast Enhancement SOMATOM Scope Factor involvein contrast enchancement SOMATOM Force Page 23 Page 24 Handzettel 4
Factors involved in Contrast Enhancement Patient size Size matter! Cardiac Output Age Page 25 Page 26 Cardiac Output Factors involved in Contrast Enhancement: kv setting SOMATOM Scope SOMATOM Force Page 27 Page 28 Factors involved in Contrast Enhancement: kv setting Factors involved in Contrast Enhancement: kv setting Relation between kv and CM enhancement Relation between kv and CM enhancement Page 29 Page 30 Handzettel 5
Factors involved in Contrast Enhancement: CM Volume Volume Injection time Saline Tubing Injection Rate Concentration Needle Temperature Page 31 Page 32 Injection Time Injection Time Page 33 Page 34 Time of Injection Injection rate Page 35 Page 36 Handzettel 6
Injection rate Flow Rate issue High Flow rate - Abdomen scan for all indication specially for GI Bleeding Liver Tumor Characterization Pancreatic Carcinoma No need high flow rate if you are interested in late portal phase only Page 37 Page 38 Concentration Concentration Higher Concentration à Higher Viscosity Contrast warm up is Mandatory Page 39 Page 40 Flush Flush Pushes contrast in tubing and peripheral veins into central veins Allows reduction in contrast volume Increase peak attenuation Reduced streak artifacts from veins and right heart Simpler to implement with dual head injector Page 41 Page 42 Handzettel 7
Needle Needle For CT Angiography We recommend using the largest gauge needle possible Site: Cubital or Ante-Cubital Fossa Large vein, low impedance = Higher flow rates Closer to heart = More contrast in circulation, less in arm Page 43 Page 44 Tubing Tubing We recommend using the tubing with the widest internal lumen Thin tuning lumen = Increased pressure = low flow rate Injector pumps @ set rate Flow is reliant on other factors. Page 45 Page 46 Temperature Temperature The temperature of the contrast greatly affects the viscosity of the contrast media. This is not linear: Concentration Temperature 18 C 21 C 37 C 300 mg I/ml @ Body Temp is 5x lower viscousity as 400 mg I/ml @ Room Temp 300 mg I/ml @ Body Temp is 2x less viscousity as 400 mg I/ml @ Body Temp 400 mgi/dl 189 140 101 370 mgi/dl 130 103 82 300 mgi/dl 75 60 54 Page 47 Page 48 Handzettel 8
Temperature Agenda Don t leave the bottle out on the bench while waiting to perform the study: In 1 hr the temperature drops by half Factorinvolvein contrast enchancement Page 49 Page 50 Contrast Access Access Big questions Cubital vien Pedal vien How much contrast do we need? What is the proper timing to get good image quality? Page 51 Page 53 How much contrast do we need? Big questions Should I go by body weight? How much contrast do we need? What is the proper timing to get good image quality? Page 54 Page 55 Handzettel 9
How much contrast do we need? How much contrast do we need? Should I go by BMI? Arnold Schwarzenegger has BMI of 33 Danny DeVito has a BMI of 33.5 Vascular region ( CT Angio) with multi slice CT (>64 slice ) can reduce amount of contrast from 100 cc to 40-60 cc follow by saline flush CTA Head & Neck CTA Whole Aorta CTA Extremity CT Coronary CT PE Venous return region BMI can be useful Body : small size patient 70-80 cc / standard to big size 100 cc Page 56 Page 57 Big questions Manual How much contrast do we need? Semi Automatic What is the proper timing to get good image quality? Automatic Page 58 Page 59 Semi Auto Timing Test Bolus Test Bolus Scan series slice @ ROI position Calculate time-to-peak Auto Techniques CARE Bolus CM injection with fix delay Scanner already at starting position Page 60 Page 61 Handzettel 10
CARE Bolus CARE Bolus Slice @ ROI position Slice @ ROI position CM injection-with scan start- actual scan start after reaching threshold CM injection-with scan start- actual scan start after reaching threshold ( 100-180HU) ( 100-180HU) Manual start can be done Manual start can be done Page 62 Page 63 Child CTA Manual Timing Recommendation Page 64 Page 65 : Manual Estimation : Manual estimation CTA ( CT Angiogram) : Study with vascular structure,arterial blood flow CTV ( CT Venogram) : Study with vascular structure,venous blood flow Timing 12-22 second Timing 45-120 second Page 66 Page 67 Handzettel 11
: Manual estimation : Manual estimation CT Chest : Study of structure within thoracic region CT Abdomen : Study of abdomen structure Timing 40-50 second Timing 50-70 second Page 68 Page 69 : Manual estimation : Manual estimation CT Soft Tissue Neck : Study structure of neck CTA Chest ( PE) : Study structure pulmonary artery Timing 50-70 second Timing 6-10 second Page 70 Page 71 : Manual estimation : Manual estimation CT Urography : Study structure of urinary tract Non Contrast Cortico-medullary phase 25-50 sec Nephrographic phase 60-140 sec Excretory phase 4-8 min CT Enterography : Study structure of the small intestine Oral contrast 3-450 bottles of VoLumenadministered 20 minute apart IV contrast timing 65 second If need arterial phase scan at 25-30 second Page 72 Page 73 Handzettel 12
: Manual estimation Thank you for your attention CT Triple phase liver : Liver area Late Arterial phase 35-40 sec excellent hepatic artery Portal venous phase 70 sec Equilibrium phase 180 sec Page 74 Page 75 Handzettel 13