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Hadeel Alkofide MSc PHCL 326 May 2011.  Differentiate between invasive & noninvasive tests  State the clinical application of common general diagnostic.

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Presentation on theme: "Hadeel Alkofide MSc PHCL 326 May 2011.  Differentiate between invasive & noninvasive tests  State the clinical application of common general diagnostic."— Presentation transcript:

1 Hadeel Alkofide MSc PHCL 326 May 2011

2  Differentiate between invasive & noninvasive tests  State the clinical application of common general diagnostic procedures  Identify the clinical application of specific laboratory tests  Identify the clinical application of specific diagnostic procedures  Assess common laboratory & diagnostic test results


4  Data from laboratory & diagnostic tests & procedures provide important information regarding  The response to drug therapy  The ability of patients to metabolize & eliminate specific therapeutic agents  The diagnosis of disease, & the progression & regression of disease

5 Invasive tests  Require penetration of the skin or insertion of instruments or devices into a body orifice  The degree of risk varies from relatively minor risks such as pain, bleeding, & bruising associated with venipuncture to the risk of death associated with more invasive procedures such as coronary angiography  E.g venipuncture, insertion of a central venous catheter, & collection of cerebrospinal fluid

6 Noninvasive tests  Do not penetrate the skin or involve insertion of instruments into body orifices & pose little risk to the patient  E.g. include chest radiograph, analysis of spontaneously voided urine, & stool occult blood analysis

7  The selection of specific tests & procedures depends on  The patient's underlying condition  The need for the information  The degree of risk  Reference ranges are listed in Tables 5-1 through 5-7  Results are interpreted using laboratory specific reference ranges  Reference ranges may differ among different laboratories depending on the population & laboratory methodology used to establish the range

8 Factors to consider when interpreting individual test results Patient age Gender Timing of the test result in relationship to drug administration Concomitant drug therapy Concurrent diseases, organ function (renal, liver, cardiac) Test sensitivity (the proportion of true-positive results) Test specificity (the proportion of true-negative results) Timing of the test in relation to drug dosing or known circadian rhythms Genetics (e.g., glucose-6-phosphate deficiency) Fluid status (e.g., euvolemia, dehydration, fluid overload)


10  A variety of tests & procedures are used to diagnose & monitor conditions that affect various organ systems  The applications & uses of these tests & procedures continue to expand with experience & the integration of new technology

11 Angiography  A radiographic test used to evaluate blood vessels & the circulation  Radiopaque material is injected through a catheter & images are recorded using standard radiographic techniques Biopsy  Removal & evaluation of tissue

12 Angiography

13 Computed Tomography  (CT; CAT scan) uses a computerized X-ray system to produce detailed sectional images  The system is very sensitive to differences in tissue density & produces detailed, two-dimensional planar images  Contrast agents increase attenuation  The spiral or helical CT takes pictures continuously, decreasing the time needed to obtain images

14 Computed Tomography

15 Doppler Echography  Uses ultrasound technology to measure shifts in frequency from moving images  E.g, Doppler echography is used to evaluate blood flow velocity & turbulence in the heart (Doppler echocardiography) & peripheral circulation

16 Doppler Echography

17 Endoscopy  Used to examine the interior of a hollow viscus (e.g., digestive, respiratory, & urogenital organs & the endocrine system) or canal (e.g., bile ducts, pancreas)  The endoscope, a flexible or inflexible tube with a camera & a light source, is inserted into a body orifice (Figure5-1)  Still &/or video images are recorded & tissues obtained for biopsy or other laboratory diagnostic tests

18 Endoscopy: Examples of common endoscopic procedures  Colonoscopy: views the inside of the entire colon from rectum to end of the small intestine  Sigmoidoscopy: views the inside of the large intestine from the rectum through the sigmoid colon  Cholangiopancreatography: views the inside of the bile ducts & pancreas  Esophagogastroduodenoscopy: views the inside of the esophagus, stomach, & duodenum  Bronchoscopy: views the inside of the tracheobronchial tree

19 Fluoroscopy  Uses a fluoroscope, a device that makes the shadows of x- ray films visible, to provide real-time visualization of procedures  It exposes a patient to more radiation than routine radiography but often is used to guide needle biopsy procedures & nasogastric tube advancement

20 Magnetic Resonance Imaging  Uses an externally applied magnetic field to align the axis of nuclear spin of cellular nuclei  The patient is surrounded by the magnetic field (Fig. 5-2)  Brief radio frequency pulses are applied to displace the alignment  The energy emitted when the displacement ends is detected resulting in finely detailed planar & three- dimensional images  Contrast agents increase the attenuation

21 Magnetic Resonance Imaging

22 Paracentesis  The removal & analysis of fluid from a body cavity Plethysmography  Measures changes in the size of vessels & hollow organs by measuring displacement of air or fluid from a containment system  Body plethysmography is used to assess pulmonary function

23 Plethysmography

24 Positron Emission Tomography (PET)  Uses positron-emitting radionuelides to visualize organs & tissues of the body  The radionuclides decay, producing positrons that collide with electrons  A special camera detects photons, released when the positrons & electrons collide  It provides quantitative information regarding the structure & function of organs & tissues

25 Positron Emission Tomography (PET)

26 Single-Photon Emission Computed Tomography. (SPECT)  Similar to PET but involves the administration of radionuclides that emit gamma rays  It is less expensive than PET but provides limited image resolution

27 Standard Radiography (Plain Films, X-Ray Films)  Produces images on photographic plates (Figure 5-3)  These films are sometimes difficult to interpret because the three dimensionality is lost on the planar images

28 Ultrasonography (Echography)  Uses ultrasound (high-frequency waves imperceptible to the human ear) to create images of organs & vessels  Ultrasonography is used to visualize the fetus in uterus


30  Cardiac Enzymes The pattern & time course of the appearance of enzymes in the blood after cardiac muscle cell damage are used to diagnose MI  Creatine Kinase  Lactic dehydrogenase (LDH)  Troponins Cardiovascular

31 Cardiac Enzymes  Creatine Kinase  Found in skeletal & cardiac muscle, brain, bladder, stomach, & colon  Isoenzyme fractions identify the type of tissue damaged  CK-MB(CK2) is found in cardiac tissue  CK-MB is detected in the blood within 3 to 5 hours after a MI  Levels peak in about 10 to 20 hrs & normalize within about 3 days Cardiovascular

32 Cardiac Enzymes  Lactic dehydrogenase (LDH)  Found in a variety body tissues  Isoenzyme fractions used to identify type of tissue damage  LDH1- LDH2 are found in the heart, brain, & erythrocytes  LDH 2 accounts for the highest % of total serum LDH  After a MI the rise in LDH 1 > the rise in LDH2  LDH ↑ within 12 hrs after an MI  It Peaks 24 to 48 hrs, & normalizes by about-day 10 Cardiovascular

33 Cardiac Enzymes  Troponins  A complex of proteins (Troponin I, C, & T) that mediate the actin & myosin interaction in muscle  Troponins I & T are specific to cardiac muscle & are used to identify cardiac muscle injury  Their concentrations ↑ within a few hrs of cardiac muscle injury & remain elevated for 5-7 days Cardiovascular

34  Cardiac enzymes: CK-MB = Creatinine Kinase-MyoGlobin Cardiovascular

35  Cholesterol  Low-density lipoprotein (LDL)is strongly correlated with coronary artery disease  High density lipoprotein (HDL)is inversely correlated with coronary artery disease  Triglycerides  Found in very low density lipoproteins (VLDLs) & chylomicrons Cardiovascular

36  C-Reactive Protein  It is a biologic marker of systemic inflammation.  Preliminary studies have linked an ↑ C-reactive protein with an ↑ risk of MI, stroke, & peripheral arterial disease  Myoglobin.  A small protein found in cardiac & skeletal muscle  The presence of myoglobin in the urine or plasma is a relatively sensitive indicator of cellular damage Cardiovascular

37  Cardiac Catheterization  Used to evaluate cardiac function  A catheter is passed into the right or left side of the heart  Right-sided catheterization is used to measure right atrial pressures, right ventricular pressures, pulmonary artery pressures, & pulmonary artery occlusion pressure  Left-sided catheterization is used to measure left ventricular pressures Cardiovascular

38  Chest Radiography.  Chest x-ray films are used to diagnose cardiac disease & monitor the patient's response to drug & nondrug therapy  The chest radiograph is used to determine the size & shape of the atria & ventricles, to calculate the cardiothoracic ratio, & to detect abnormalities in the lung fields & pleural spaces  Coronary Angiography  In coronary angiography the cardiac vessels are visualized by injecting the vessel with a contrast agent Cardiovascular

39  Echocardiography  Used to evaluate the size, shape, & motion of the valves, & walls & changes in chamber size during the cardiac cycle Cardiovascular

40  Electrocardiogram (ECG)  Records the electrical activity of the heart (Figure 5-5)  used to diagnose cardiac disease, monitor the patient's response to drug therapy, & monitor for adverse drug effects  12 separate leads, 6 extremity (limb) leads & 6 chest leads create a three-dimensional view of cardiac electrical activity Cardiovascular

41  Electrocardiogram with Stress (Stress Test)  The ECG is recorded during standardized exercise protocol with gradually increasing level of exercise or with patient at rest after administration of dobutamine or dipyridamole  Either intervention increases myocardial oxygen consumption and blood flow  BP, HR, O2 consumption, O2 saturation, & arterial blood gases are collected to provide a thorough assessment of how the CV system functions under stress conditions Cardiovascular

42  Electrocardiography  Holter Monitoring (Ambulatory Electrocardiography)  A portable recorder to record the ECG continuously throughout usual patient activity  Thallium Stress Test  It combines the parenteral administration of thallium-201, a radionuclide taken up by healthy myocardial tissue, and the stress test (either exercise or pharmacologic)  A gamma camera is used to record serial images of the myocardium Cardiovascular

43  Technetium-99m Pyrophosphate Uptake.  Infarcted myocardial tissue has an increased uptake of technetium-99m compared with healthy tissue  The isotope is injected parenterally, & serial images of the heart are obtained to evaluate the location & extent of the myocardial infarction Cardiovascular


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