Computed Tomography Scanning for Diagnosing Appendicitis - Research Paper Example

IV-Constrasted vs. Non-contrasted Abdominal Computed Tomography (CT) Scan in the Diagnosis of Appendicitis By 09000979 0. Introduction Computed tomography (CT) has variously been called as computerized axial tomography (CAT), computerized trans-axial tomography (CTAT) or digital axial tomography (DAT). This technology revolutionized imaging science since it was first introduced during the 1970s (Bushong, 2000). To date, it is considered by experts as the “primary imaging modality for evaluation of acute right lower quadrant pain” (Oto and Ernst, 2008, p. 300). Bushong (2000) maintained that there are at least five advantages offered by computed tomography over conventional radiography: (1) better contrast resolution (2) no superposition of tissue (3) less scatter radiation (4) 3D imaging capability, and (5) capability for bone mineral assay. The standard practice at the Khalifa Medical City (SKMC) in Abu Dhabi is that a CT scan of the abdomen is requested after initial clinical examination and blood works have been performed in the Emergency Room. However, if the patient is either very young or an adult female, the ultrasound is the modality of choice. When the prior ultrasound yields inconclusive results, it is only then that a CT scan is performed on these two groups of patients. From the proponents’ observation, though, all patients ultimately undergo a CT scan for diagnosis of appendicitis, whether clinical examination and blood works find the symptoms typical or atypical.  As imaging science advanced considerably through the last three decades, contrasts have been used with CT scans, particularly the oral, rectal and intravenous types. As a CT radiographer in SKMC, the proponent observed that some radiologists prefer non-contrasted examinations for the diagnosis of appendicitis, while others prefer contrasted CT examinations. To date, no standard protocol is in place at the SKMC regarding the use of IV contrasted and non-contrasted or plain CT scans. The non-existence of such protocol is believed to stirring some confusion among the emergency room (ER) doctors. Hence, the proponent’s decision to undertake a study on this area. According to Perkins, Kahan and McCue (2008), a CT scan with oral and IV contrast is recommended for diagnosis of appendicitis. Some practitioners prefer the use of rectal contrast to avoid unnecessary delays in appendicitis diagnosis and treatment intervention. With regards to contrasts, Novelline (2004) explained that contrast media are utilized during abdominal CT examinations for two fundamental reasons: (1) to provide opacity of the gastro-intestinal tract, in which usually, oral contrast is the medium of choice. The colon may, however, be directly opacified using a rectal contrast; (2) IV contrast, on the other hand, results in a temporary increase in the density of the arteries, all capillary-perfused parenchyma and peripheral veins which is of greatest utility in the identification of abdominal pathology. A survey of related literature, however, revealed that published opinions vary. Knopp and Hokanson (2006) admitted that there is yet no consensus approach in medical literature as to the use of contrast in the CT examination of patients with expected appendicitis. The three modes of contrast administration: intravenous (IV), oral and rectal are either administered singly or in combination as one of the methods of evaluating appendicitis or acute appendicitis. Use of non-contrast abdominal CT scan is also an acceptable method for patients with enough adipose tissue. Based on laboratory and clinical experience Knopp and Hokanson (2006) indicated the following range of sensitivities, specificities, positive and negative predictive values, respectively for all helical CT with all approaches (contrast or non-contrast) in appropriate patient : 92-96%, 89-99%, 90-97% and 95-98%. Thus, Knopp and Hokanson considers that the most important determining factor in selecting plain vs. contrast, and/or which mode of contrast is the recommendation of an experience radiologist. General protocol in CT scan examination specify that adult patients should have sufficient adipose tissue for a non-enhanced (or non-contrast) CT. Otherwise, intravenous and oral contrast is to be used after checking the patient’s creatinine. If the oral-IV contrast fails to present definitive results, rectal contrast may then be considered (Knopp and Hokanson, 2006). Reisdorff and Schwartz (2000) believes that an optimal CT examination of the abdomen is achieved by using the IV-oral contrast combined. When used to opacify the gastro-intestinal tract, the duo prescribed administration of the oral contrast over a two hour period, although they qualified that in emergency cases where two hours of delay may not be practical, the time of administration may be shortened with very little loss of information. Reisdorff and Schwartz (2000), however, underscored that IV contrast should be the medium of choice for the detection of vascular lesions and abnormalities of the bowel Skucas (2005) indicated that the significant improvement in the sensitivity of identifying an inflamed appendix is observed with the use of intravenous (IV) contrast. Additionally, combined usage of oral and IV contrasts among children with suspected appendicitis attained a sensitivity of 97% and a specificity of 93%. There are also protocols which combine oral and rectal contrast. It was, however, observed that use of oral contrasts present a disadvantage regarding the time needed before the contrast highlights the ileocecal region. Also, a contrast enema administered enough to opacify the cecum, helps in defining the adjacent structures and cecal wall opening. The contrast enema, though, is more beneficial for children than in adults, especially children with little abdominal fat. Oto and Ernst (2008) offered estimates of the time required for oral and IV contrast before a CT scan can be performed. Administration of oral contrast requires about 1 to 2 hours, while in IV-contrast only protocols, CT examination may be performed within minutes. Differential diagnosis of diverticulitis and appendicitis which are usually difficult to make also benefits from a CT scan with contrast (Silen, 2005). Results of the following studies which have either direct or indirect bearing in this study are also argumentative and often contradictory. Sivit (2004) compared the advantages of CT scan vs. sonography and found out that the main advantages of CT are its operator independency with resultant higher diagnostic accuracy, improved definition the extent of disease in perforated appendicitis, and better patient outcomes specially decreased negative laparotomy and perforation rates. Meanwhile, the study of Tamburrini, Brunetti, Brown, Sirlin and Casola (2006) revealed that non-enhanced CT resulted in 75% conclusive findings among 536 patients. Sensitivity, specificity, and positive and negative predictive value for the diagnosis of acute appendicitis were: (1) 90%, 96.0%, 84.8%, and 97.4% in patients with conclusive NECT (n = 404); (2) 95.6%, 92.3%, 73%, and 99% in patients with inconclusive NECT followed by repeat CT with contrast; and (3) 91.3%, 95%, 82%, and 98% in all patients. On the other hand, on the basis of a meta-analysis of eligible studies, Weston, and Blamey (2005) concluded that CT has better sensitivity and specificity than the ultrasound. However, the researchers felt the need to undertake a cost-benefit analysis of the vaunted better performance of the CT against its costs and availability. Anderson, Salem and Flum (2005) systematically reviewed the diagnostic performance of a CT scan with and without administration of contrasting material. The results showed that non-contrast CT scan techniques provided equal, if not superior diagnostic performance compared to CT scan with oral contrast in the diagnosis of appendicitis. It was recommended that further comparative trials be performed to gauge the adequacy of this modality. Mun, Ernst, Chen, Oto, Shah and Mileski (2006) confirmed that CT with IV contrast is sensitive and specific for the confirmation or exclusion of acute appendicitis even without oral contrast, hence, by eliminating the time required to administer oral contrast in administering IV constrast alone, diagnosis may be accomplished in less time. Musunuru, Chen, Rikkers and Weber (2007) evaluated the utilization of CT scans in patients with suspected appendicitis to gauge test sensitivity and effect on clinical outcomes. Imaging results from adult patients with presumed acute appendicitis were correlated with surgery findings. Results from the study led to the conclusion that the utilization of CT scan on suspected appendicitis patients before surgery should be done selectively as this may have a negative impact on the clinical outcome such as delay inoperative intervention and potentially higher rate of perforation. On the other hand, Rhea, Halpern, Ptak, Lawrason, Sacknoff and Novelline (2004) analyzed the medical records of 753 patients with suspected appendicitis with the purpose of determining the percentage of patients that underwent abdominal CT, incidence of appendicitis, accuracy of CT scan, percentage of ambiguous or uncertain interpretations, and negative appendectomy rates for patients who did and did not undergo CT scan. The results of the study has shown that patients who did not undergo CT scan had a lower negative appendectomy rate. On the other hand, the incidence of appendicitis on patients who had undergone CT scan is stable compared to similar prior studies. 2.0. Aims and Hypotheses The purpose of this study is to examine the efficacy of IV contrasted against non-constrasted CT scan examination with the end in view of establishing a protocol for the patients of the Sheikh Khalifa Medical City (SKMC) in ruling out appendicitis. Specifically, the following research objectives will be carried out: 1. Compare the efficacy of IV constrasted against non-contrasted CT scan in ruling out appendicitis in terms of sensitivity, specificity and predictive value. 2. Obtain the opinion of patients pertaining to their experience in undergoing CT scan in terms of administration and convenience. 3. Describe the profile of the study participants in terms of their gender, age and presenting symptoms. 4. Test the hypothesis that “there is no significant difference between IV contrasted and non-contrasted CT scan in ruling out appendicitis” using a 0.05 level of significance and two-tailed analysis. 5. Test the hypothesis that “there is no significant difference in the experiences of the patient participants when they are grouped according to gender, age, and presenting symptoms, using a 0.05 level of significance and two-tailed analysis. 3.0. Ethical Considerations The proposed study will be conducted grounded on the fundamental ethical principles of beneficience, non-maleficience, autonomy and justice (Barrett, 2006). In this regard, efforts will be concentrated on the acquiring of all necessary permits and authorizations before actual data gathering takes place. To date, the proponent has already filled out forms for the use of patient record database of the hospital for approval of the manager of the radiology department and the hospital information medical systems department (HIMS). Once this form is approved another form will be completed and sent to the hospital Research Ethics Committee for approval. Approval will also be secured from the Queen Margaret University Ethics Board. In addition engagement of subjects or study participants will be assured of voluntary participation and informed consent. In this regard appropriate documents pertaining to their voluntary participation and informed consent will be signed by each research participant and the study adviser. A sample informed consent form together with a cover letter is provided as an appendix to this proposal. 4.0. Methods The descriptive method of research will be employed in this study. Analysis of existing patient records from HIMS and the survey will be the techniques of research to be utilized. The procedure for the analysis of patient records will be carried out based on Stommel and Wills (2004). The primary research instruments in this regard will be the patient records and the questionnaire to be prepared by the research proponent. Since an average of about 47 patients have been serviced in the hospital CT scan department, the proponent plans to engage at least 42 patients as voluntary participants in the city. The number 42 is a random sample calculated based on a 95% level of confidence, a 5% margin of error, a population size of 47 patients in one year, and a maximum value for response distribution of 50%. Computation was carried out using an online sample size calculator (Raosoft, 2004). Independent samples t-test will be employed to test the first hypothesis of the study using non-directional analysis (two-tailed) and a 0.05 level of significance. Independent samples t-test (for gender, type of patient and CT scan medium used) and one way analysis of variance (for age and ethnicity) or ANOVA will be used to assess whether experiences of patients with the CT scan are a function of one or more of the profile variables considered in the study, which is the second hypothesis of the study. Non-directional analysis (two-tailed) and a 0.05 level of significance. Levene’s test for homogeneity of variance will be used to check if the data collected for each variable conformed with assumptions of normality. In the ANOVA procedures, appropriate post hoc analysis methodology will be employed to assess which among pairs of variables significantly differ. For ANOVA with equal variances assumed, the Bonferroni multiple comparisons test will be used; whereas, for ANOVA with equal variances not assumed, Tamhane’s T2 post hoc test will be utilized. 5.0. Timetable The tentative timetable for the proposed study will run for a period of seven months from December, 2009 to July 2010. The main tasks in the conduct of the proposed research study were classified into four groups: (1) preparation (2) experiment (3) analysis and (4) writing up. These tasks are shown in the flow diagram in Figure 1 mapped out into a time scale. The Preparation stage of the research will be carried out within 14 weeks starting from the first week of December, 2009. Activities included under the preparation stage are proposal preparation, securing of permissions for data collection and ethical permissions from the Queen Margaret University Research Ethics Committee, the Sheikh Khalifa Medical City Board and the SEHA (Abu Dhabi Health Services Company) Research Ethics Committee. Also, a full research proposal would require an extensive survey of related literature and studies, which is very time-intensive task. The longest amount of time is, therefore, allocated for preparatory work, considering the possibility of having to revise the proposal to comply with the recommendations of the school ethics committee or to make the goals of the study more achievable. Meanwhile, the experiment stage is the research proper where the researcher will collect the necessary data based on the requirements of the study. A total of ten weeks will be allotted for this stage, which will start on Week 15 (mid-March) and end on Week 24 (end of May). The whole month of June (Week 25 to Week 28) will be allotted for the encoding and statistical analysis of the data gathered. Finally, write up of the results and discussions of the findings of the study and the conclusions and recommendations will be undertaken during the whole month of July (Week 29 to Week 32). December, 2009 Week 1 Week 2 Week 3 Week 4 January, 2010 Week 5 Week 6 Week 7 Week 8 February , 2010 Week 9 Week 10 Week 11 Week 12 March, 2010 Week 13 Week 14 Week 15 Week 16 April, 2009 Week 17 Week 18 Week 19 Week 20 May, 2010 Week 21 Week 22 Week 23 Week 24 June, 2010 Week 25 Week 26 Week 27 Week 28 July, 2010 Week 29 Week 30 Week 31 Week 32 Figure 5.1: Proposed timetable for the study 6.0. References Anderson, B., Salem, L., Flum, D. 2005. A systematic review of whether oral contrast is necessary for the computed tomography diagnosis of appendicits in adults. The American Journal of Surgery, 190(3), pp. 474-478. Barrett, J. 2006. Ethics in clinical research. Buckinghamshire, UK: Institute of Clinical Research. Bushong, S. C. (2000). Computed tomography. New YorK: McGraw-Hill Companies Knopp, R. & Hokanson, J. 2006. Small Bowel. In: R. V. Aghahabian, E. J. Allison, Jr., E. W. Boyer, G. R. Braen, M. M. Manno, J. C. Moorhead, & G. A. Volturo, eds. Essentials of Emergency Medicine. London: Jones and Bartlett Publishers International, pp. 75-83. Mun, S., Ernst, R. D., Chen, K., Oto, A., Shah, S. & Mileski, W. J. 2006. Rapid CT diagnosis of acute appendicitis with IV contrast material. Emergency Radiology, 12(3), pp. 99-102. Musunuri, S., Chen, H., Rikkers, L. F. & Webber, S. M. 2007. Computed tomography in the diagnosis of the acute appendicitis: definitive or detrimental? Journal of Gastrointestinal Surgery, 11(11), pp. 1417-1422. Novelline, R. A. 2004. Squire’s fundamentals of radiology. 6th ed. Cambridge, MA: Harvard University Press. Old, J. L., Dusing, R. W., Yap, W. & Dirks, J. 2005. Imaging for suspected appendicitis. American Family Physician, 71(1), pp. 71-78. Oto, A. & Ernst, R. D. 2008. Computed Tomography. In: C. E. H. Scott-Conner, ed. The SAGES Manual of Strategic Decision-Making: Case Studies in Minimal Access Surgery, New York: Springer Science + Business Media, LLC, pp. 300-303. Perkins, J., Kahan, S. & McCue, J. D. 2008. In a page: inpatient medicine. Philadelphia, PA: Lippincott, Williams & Wilkins. RadiologyInfo. (2009). How does the procedure work? [online]. [Accessed 19 December 2009]. Available from the World Wide Web: http://www.radiologyinfo.org/en/info.cfm?PG=bodyct Raosoft. 2004. Sample size calculator [online]. [Accessed 12 December 2009]. Available from the World Wide Web: http://www.raosoft.com/samplesize.html Reisdorff, E. J. & Schwartz, D. T. 2000. Introduction to Emergency Radiology. In: D. T. Schwartz & E. J. Reisdorff, eds. Emergency Radiology, New York: McGraw-Hill Companies, pp. 1-10. Rhea, J. T., Halpern, E. F., Ptak, T., Lawrason, J. N., Sacknoff, R. & Novelline, R. A. 2004. The status of appendiceal CT in an urban medical center five years after its introduction: experience with 753 patients. American Journal of Roentgenology, 184, pp. 1802-1808. Silen, W. 2005. Cope’s early diagnosis of the acute abdomen. 21st ed. New York: Oxford University Press. Sivit, C. J. 2004. Imaging the child with right lower quadrant pain and suspected appendicitis: current topics. Pediatric Radiology, 34(6), pp. 447-453. Skucas, J. 2005. Advanced imaging of the abdomen. London: Springer-Verlag. Stommel, M. & Wills, C. E. 2004. Clinical research: concepts and principles for advanced practice nurses. Philadephia, PA: Lippincott, Williams & Wilkins. Tamburrini, S., Brunetti, A., Brown, M., Sirlin, C. & Casola, G. 2006. Acute appendicitis: diagnostic value of non-enhanced CT with selective use of contrast in routine clinical settings. European Radiology, 17(8), pp. 2055-2061. Weston, A. R., Jackson, T. J. & Blamey, S. 2005. Diagnosis of appendicitis in adults by ultrasonography or computed tomography: a systematic review and meta-analysis. International Journal of Technology Assessment in Health Care, 21(3), pp. 368-379. Appendix A COVER LETTER December 19, 2009 Dear Respondent : This survey is being conducted as part of a purely academic exercise in partial fulfillment of the requirements for a bachelor’s course in Radiography at the Queen Margaret University . However, although this is a student research, the investigation will be monitored by my faculty supervisor named below, to see ensure that the study is carried out under the highest standards of scholarship and ethics. It is believed that the investigation does not entail a sensitive area and will not expose the respondents to any possible risks, since only perceptions of your experience in the CT scan department are being elicited. Please be aware that we only enjoin patients 18 years or older to participate in this research project. If you are not satisfied with the manner in which this study is being conducted, you may report (anonymously if you so choose) any complaints Research Ethics Committee of the Queen Margaret University at please indicate contact details here of the research committee. Your kindest cooperation is solicited for the completion of the proposed study. To guarantee your anonymity, you will not be requested to indicate your name in the survey questionnaire. Please make sure that when this questionnaire is returned during collection, it is sealed in the original envelope handed to you together with this letter. Please be assured, however, that all your responses will be treated with utmost confidentiality. Your sealed responses will only be viewed by myself during data processing. Submission of the accomplished questionnaire to this researcher is an indication of your voluntary consent to participate in this research project. Thank you. Sincerely, Please indicate your full name here Researcher Contact Information: Your Full Name Your Address Ph: Your phone number here E-Mail: Your email address Faculty Contact Information: Your faculty supervisor here E-Mail: Your supervisor’s e-mail address here Appendix B SURVEY QUESTIONNAIRE IV-Constrasted vs. Non-contrasted Abdominal Computed Tomography (CT) Scan in the Diagnosis of Appendicitis Patient Control No. _____ Dear Respondent : This survey is being conducted as part of a purely academic exercise. Your cooperations is solicited for the completion of the proposed study. Please be assured that all your responses will be treated under conditions of utmost confidentiality. Submission of the accomplished questionnaire to this researcher or representative is an indication of your consent to participate in this research study. Thank you. The Researcher Instructions : Kindly answer each of the following questions by writing down the answer on the space provided for or selecting among the given choices by marking the appropriate box. It will be much appreciated if you will not leave any questions unanswered. Part I. Profile of Respondent 1. Gender :  Male  Female 2. Age (In years): _______ 3. Ethnicity:  White  Black  Others - Specify : _________ 4. Please mark the appropriate patient detail :  Out-patient  In-patient 5. CT scan medium :  IV-contrasted  Non-contrasted (plain) Part II. Perceptions On Selected Issues Relating to CT Examination Experience (Adapted from RadiologyInfo, 2009). Kindly indicate the extent of your agreement/disagreement with the following statements by checking the corresponding box. Please use the following scale:  5 – Strongly Agree  4 – Slightly Agree   3 - Neutral   2 – Slightly Disagree  1 – Strongly Disagree  5. The over-all experience may be described as pleasant.  5  4  3  2  1 6. I experienced discomfort from having to remain still for several minutes.  5  4  3  2  1 7. I am claustrophobic and I find the experience stressful.  5  4  3  2  1 8. The chronic pain I am experiencing during my CT examination made the experience stressful.  5  4  3  2  1 9. I was given some form of sedative to help me tolerate the pain from the CT examination procedure.  5  4  3  2  1 10. I experienced a warm flushed sensation as the IV-contrast medium is being injected.  5  4  3  2  1 11. I experience a metallic taste in my mouth.  5  4  3  2  1 12. I experienced a sensation that I have to urinate as the contrast is being injected intravenously.  5  4  3  2  1 13. I find the slight buzzing, clicking and whirring sounds of the CT equipment tolerable.  5  4  3  2  1 14. I am relieved that even if I am alone in the CT examination laboratory, the radiographer can see, hear and speak to me whenever necessary.  5  4  3  2  1 15. I was given special instructions regarding the contrast material after the examination is completed. Appendix C INFORMED CONSENT IV-Constrasted vs. Non-contrasted Abdominal Computed Tomography (CT) Scan in the Diagnosis of Appendicitis I am conducting research on IV-contrasted vs. plain abdominal CT scan.  I am investigating this because of the existing need for a definite set standards regarding the type of CT examination to be used by radiologist for the diagnosis of appendicitis. By implementing standard procedure in this respect, it is hoped that that services provided by the hospital will be improved. If you take part in this research project you will be asked to answer a short questionnaire regarding your experiences during your CT examination at the Sheik Khalifa Medical City in Abu Dhabi, United Arab Emirates. We do not expect you to feel any physical discomfort nor sustain an injury during the procedure since standard methodology will be observed.  You will not be required to write you name on the questionnaire to protect your anonymity. After you have completed the questionnaire, it will be collected and stored in a secure location to safeguard the confidentiality of your responses. After the study has been defended before a refutable panel of jurors and has passed rigorous academic standards, the questionnaires will be shredded and disposed by incineration. Taking part in this project is entirely up to you, and no one will hold it against you if you decide not to do it.  If you do take part, you may withdraw at any time.  In addition, you may ask to have your data withdrawn from the study after the research has been conducted. If you want to know more about this research project, please contact me at phone # & email address, include advisers name, phone number, and email address if appropriate]. This project has been approved by the Queen Margaret University Research Ethics Committee, Sheikh Khlaifa Medical City Board and SEHA (Abu Dhabi Health Servcies Company) Research Ethics Committee. Information on Queen Margaret University policy and procedure for research involving humans can be obtained from ____________________, telephone ____________________.  You will get a copy of this consent form. Sincerely,    [Name, title] I agree to take part in this project.  I know what I will have to do and that I can stop at any time. ________________________________       Date Signature  and Patient Control Number                                                     Read More