Path Test 1 Review PDF

Lecture 1 - - - - - The inherent of natural contrast within the body CT scans gives better images because they are in slices MRI has a wide range of gray value Low subject contrast ● Brain vessels. Chest cavity, soft tissues Natural mineral salts -> calcium in bone Open fracture: bone is expose...

Lecture 1 - - - - - The inherent of natural contrast within the body CT scans gives better images because they are in slices MRI has a wide range of gray value Low subject contrast ● Brain vessels. Chest cavity, soft tissues Natural mineral salts -> calcium in bone Open fracture: bone is exposed to the outside You see gas in open fractures You see calcium in kidney stones and vessels Negative contrast - goes through air easily and nothing obstruct ● Anatomic areas filled by agents appear DARK on the image ● Composed on elements with low atomic numbers Positive contrast - white and light gray areas ● X-radiation is absorbed by radiopaque contrast media ● Anatomic areas filled by these agents appear light on the image ● Composed on elements with high atomic numbers Directly into body orifices communicating with the outside of body Indirectly via the circulatory system to organs Direct injection into vessels or ducts Injection into closed body cavities Barium sulphate ● Anti-foaming agent: adding to avoid the creation of small air bubbles that may mimic pathology ● Suspending agent: stabilizing/ suspending agents prevents flocculation Viscosity refers to how easily the barium flows ● Viscosity is extremely important for double contrast ● Low viscosity - flows more rapidly ● High viscosity - flows more slowly To avoid embolus formation and to be normally exerted by the urinary tract Properties of an ideal intravascular contrast agent ● Highly soluble in water ● Readily excreted by the kidneys ● Chemically stable ● Low toxicity ● High opacity ● High miscibility ● Low viscosity ● Reasonable Ionic ● when dissolved in a solution ionics dissolve into two charged particles 1. Cation + 2. Anion ● For every 2 charged particles there are 3 iodine atoms Non ionic ● Do not dissociate in solution results in fewer particles in solution and the particles have no charge ● Non ionic contrast results in the same number of iodine atoms but fewer particles in solution Advantages of non-ionic contrast ● Fewer adverse reactions due to fluid shift ● Lower toxicity ● Same opacity (as ionic) Disadvantages on non-ionic contrast ● Cost Iodine concentration - increase concentration = increased viscosity Temperature - increase temperature = decrease viscosity Lecture 2 Step ladder: gas pattern (small bowel obstruction) Distal (further through the small obstruction) Factors that affect its positions ● Body habitus (people are built different) ● Body position ( erect or supine) ● State of respiration (diaphragm, while breathing) ● State of fullness ● Muscle tone fat deposit ● Pregnancy 1. Hypersthenic (organs higher up) 5% 2. Sthenic 3. Hyposthenic (lower down) 5% Peristalsis: contraction waves by which the GI contents are propelled towards the rectum Increased transit time 1. Buscopan ● Holds stomach still while exam is carried our ● Allows bowel to dilate ● 15-20 mins ● Side effects: blurred vision, dry mouth, fast heart rate, urinary retention 2. Glucagon ● More potent (stronger) than Buscopan ● Action within 1 minute and last about 15-20 mins ● Disadvantages: expensive and allergic reactions poss 3. Maxolon or maxeran (helps things getting going) ● Gastric peristalsis - - 3 methods of patient preparation for abdominal x-ray procedure 1. Diet ● Clear fluid diet often ordered for 24-48 hours before Ba examination no dairy products ● Low residue diet ( nothing that causes stool and poop) ● NPO nothing by mouth fasting for 8-12 hours before the examination assures empty stomach 2. Laxatives ● Irritant or stimulant purgative ● Softens feces by allowing water to penetrate it ● Bulk purgative works quickly 1-3 hours by higher volume of intestinal content ● Hydrating agent causes the bowel to hold more water ● Combination osmotic 3. Enema ● Cleans the bowel and empty it of feces ● Introduce drugs ● Introduce fluids ● Diagnostic or therapeutic procedure ● Types of cleansing including water, hypertonic, saline, soapsuds, oil retention Types of cleansing enemas ● Tap water, hypertonic, saline, soap suds Lecture 3 Barium Swallow (Gl tract) A. Patient preparation B. Examination - hospital gown remove all clothing and metallic wear Indication is pain, dysphagia and difficulty in swallowing Contraindications - sensitivity or perforation, contrast: barium think and thick Procedure ● Erect position ● Mouthful of barium -> swallow and hold in mouth until told so 35-40 degree LPO/RAO and left lateral are the best demonstrations that the ESO without superimposition and the complications are leakage of barium due to perforation and aspiration Demonstration of esophageal reflux 1. Breathing exercises 2. Water test 3. Compression paddle technique 4. Toe touch Demonstration of esophageal varices 1. Recumbent position - blood flows vs gravity 2. Valsalva maneuver 3. Full exhalation Procedure 1. Position erect 2. Gas producing agent given 3. Small amount of H20 or Ba 4. DON'T BURP 5. Patient drinks for ba 6. May do esophagus imaging now 7. Rollover 8. More imaging as required 9. Drugs to inhibit motility 10. Various positions to visualize all areas while imaging Supine position - barium at the top and air at the bottom Prone and erect - barium at the bottom and air at the top Lecture 4 Abnormal structures in the esophagus 1. Extrinsic pressure (outside) ● Aortic aneurysm ● Tumor in the vicinity ● Achalasia ( brain and cardiac sphincter don't communicate anymore) 2. Intrinsic pressure (inside) ● Varices ● Neoplasia (new growth) ● Esophagitis Major symptoms include Dysphagia trouble in swallowing and heartburn due to acidic stomach content including spicy food Causes of esophagitis ● Reflux of gastric content GERD ● Prolonged vomiting ● Incompetent LES (lower Esophageal sphincter ● Irritant foods (spicy alcohol and caffeine) ● Tube down to throat Schatzkis rings are scar tissue that develops due to long exposure and prevents sphincter from working properly Esophageal cancer ● Common in male 50-70 years ● 5 year survival rate less than 10% ● Late symptoms including pain on eating and bleeding ● Lower ⅔ of esophagus majority of tumor highly malignant direct spread ● Correlation with high alcohol intake and smoking ● Progression results in a decrease in caliper of the lumen ● Further progression can result in obstruction proximal dilation - - ● Ct staging next step ● Treatment photodynamic therapy - laser activated chemicals destroy the tumor Zenker's diverticulum ● Characterized by a large outpouching of the esophagus just above UES and weakening of muscle wall ● Symptoms are dysphagia, aspiration, late regurgitation of food eaten hours earlier Achalasia - aka cardiospasm ● Absence or degeneration of the autonomic cells in the lower esophagus ● A functional obstruction of the distal esophagus ● The signal for peristalsis does not get through ● The esophageal sphincter does not relax and open ● Treatments include drugs to relax sphincter, balloon dilation, endoscopic guidance botox ● Surgery-laparoscopic myotomy Radiographic appearance ● Diffuse round and oval filling defects aka Rosary beads Lack of continuity of esophagus commonly associated with T/E fistula Imaging ● Plain films - chest and abdomen total absence of air in the stomach/bowel indicates a complete atresia with no fistula ● Water soluble contrast study would demo the extent of the blind pouch TE fistula causes ● 50% caused by mediastinal malignancy esophageal ● Infectious process ● Trauma ● Esophagus instrumentation perforation ● Can be found anywhere along the esophagus Lecture 5 Small bowel 7m (23FT) in length Diameter 3.8cm (proximal) distal 2.5 cm Large intestine begins right lower quadrant at the ileocecal valve (1.5m long and 6cm in diameter) 4 methods of examining the small intestine ● UGI and small bowel typically combined ● Small bowel only series ● Enterclyssi ● Intubation method ● Functional study of motility ● Small bowel obstruction has step ladder ● Malabsorption syndrome patient seems malnourished ● Crohn's disease aka regional enteritis Patient prep includes “ empty stomach, NPO 8 hours, No smoking or gum, empty bladder and pregnancy protocol” Procedure “ wait 30 mins for the image and see where barium is To speed up the process ask the patient to lay on the right side to empty stomach faster Methods to increase peristalsis and decrease transit time ● Lie on right side ● Glass of ice water ● Saline instead of water as barium decreases viscosity ● Add gastrografin to barium ● Drugs - metoclopramide Double contrast small bowel study ● Aka small bowel enema ● Contrast medium is injected into the small bowel through a tube placed into the duodenal jejunal junction Enteroclysis advantages ● Better visualization of small bowel than SBFT ● No segmentation as in one chunk ● Rapid infusion does not allow flocculation which prevent from flowing Disadvantages ● Increased patient discomfort ● Possibility of perforation