(Radiology. 2000;216:172-177.)
© RSNA, 2000
Diagnosis of Acute Appendicitis: Comparison of 5- and 10-mm CT Sections in the Same Patient1
David I. Weltman, MD,
Jinxing Yu, MD,
John Krumenacker, Jr, MD,
Steven Huang, MD and
Paul Moh, MD
1 From the Department of Radiology, Nassau County Medical Center, 2201 Hempstead Turnpike, East Meadow, NY 11554. Received June 21, 1999; revision requested August 10; revision received October 18; accepted October 25. Address correspondence to D.I.W. (e-mail: dweltman@ncmc.edu).
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ABSTRACT
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PURPOSE: To compare 5- and 10-mm computed tomographic (CT) sections in the same patient to diagnose acute appendicitis.
MATERIALS AND METHODS: During an 11-month period, 100 consecutive patients clinically suspected to have acute appendicitis underwent abdominal and pelvic CT. Helical, 10-mm-collimated sections from the diaphragm to the pubic symphysis and 5-mm-collimated sections through the lower part of the abdomen and upper part of the pelvis were obtained. The 10- and 5-mm sections from each patient were separated into two groups and were interpreted independently by two abdominal imaging attending physicians who were blinded to the final results. The interpretations were correlated with the histopathologic or final clinical diagnoses.
RESULTS: Data analysis from blinded reader interpretations of the 5- and 10-mm sections, respectively, revealed sensitivities of 99% and 82% (P < .001), specificities of 98% and 95% (P = .426), and accuracies of 99% and 89% (P < .001). Among the 48 cases of acute appendicitis, abnormal appendices were identified in 94% (n = 45) and 69% (n = 33) (P < .05) on 5- and 10-mm-collimated sections, respectively. Right-lower-quadrant inflammatory changes were identified in 98% (n = 47) and 71% (n = 34) (P < .05) on 5- and 10-mm-collimated sections, respectively. Normal appendices were identified in 75% (n = 39) and 52% (n = 27) of the 52 negative cases on 5- and 10-mm sections (P = .025), respectively.
CONCLUSION: Use of thin-section CT significantly improves the diagnosis of acute appendicitis.
Index terms: Appendicitis, 751.291 • Appendix, CT, 751.12112, 751.12115, 751.12118 • Computed tomography (CT), high resolution, 751.12118
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INTRODUCTION
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The percentage of unnecessary appendectomies that result from the clinical false-positive diagnosis of appendicitis is 8%–43%, with a mean of about 20% (1–5). Laparotomy can be avoided in many patients if modern diagnostic methods are used to confirm or exclude acute appendicitis. Computed tomography (CT) and ultrasonography are the primary imaging methods used (6–12).
To maximize diagnostic accuracy, a variety of CT protocols for the diagnosis of acute appendicitis have been reported (9–14). Malone et al (11) reported a sensitivity of 87% (65 of 75 cases) in diagnosing acute appendicitis with nonenhanced CT by using 10-mm collimation at 10-mm intervals. A focused CT technique with 5-mm collimation and with rectally administered contrast material was reported to be 100% sensitive in the evaluation of patients clinically suspected to have appendicitis (12,13).
To determine if there are advantages of using 5-mm collimation over 10-mm collimation, we prospectively evaluated 5- and 10-mm-section CT scans in 100 consecutive patients examined at our hospital for suspected appendicitis.
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MATERIALS AND METHODS
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Patient Population
This study included 100 consecutive patients suspected of having appendicitis who underwent abdominal and pelvic CT in our hospital during an 11-month period. Each patient had two or more clinical symptoms or signs associated with appendicitis that included but were not limited to right-lower-quadrant pain, nausea, vomiting, anorexia, initial periumbilical pain, fever, and elevated white blood cell count. The decision to refer the patient for imaging was made by an emergency department physician or by a surgical attending physician if the clinical features were considered insufficient for diagnosis.
There were 54 male and 46 female patients, who ranged in age from 3 to 73 years (mean age, 34 years). Fifty-eight (55%) patients underwent appendectomy without undergoing preoperative CT during the same period.
CT Technique and Contrast Material Administration
Examinations were performed with a helical CT scanner (XPress/SX; Toshiba, Irvine, Calif). All patients received 400–800 mL of 2% diatrizoate sodium solution (Hypaque; Nycomed, Princeton, NJ) orally at least 1 hour before scanning. Ninety-two patients received up to 1,500 mL (mean adult volume, 900 mL), as tolerated, of 2% diatrizoate meglumine solution through a rubber rectal catheter. The remaining eight patients refused the rectal administration of contrast material. An intravenous bolus injection of 120–150 mL of ionic (60% iothalamate meglumine [Conray; Mallinckrodt, St Louis, Mo]) or nonionic (61% iopamidol [Isovue-300; Bracco, Princeton, NJ]) iodinated contrast material was given at 2 mL/sec. Helical, 10-mm sections at 10-mm intervals were obtained from the diaphragm to the pubic symphysis and were followed with 5-mm sections at 5-mm intervals in the lower part of the abdomen and in the upper part of the pelvis. For interpretation, the images were displayed at a standard window width and level setting.
This technique was adopted prior to the start of the study as our department's routine protocol for the CT evaluation of patients suspected to have appendicitis and is still in use at the current time.
CT Scan Interpretation
Each CT scan was interpreted immediately by a single, board-certified faculty radiologist (including D.I.W., J.K., and P.M.) or by a senior radiology resident on call and was reviewed by an attending radiologist the next day. Results were made known immediately to the referring clinician, who integrated the CT results into the final case management decision. The results of these interpretations were not included in this study, with the exception that alternate diagnoses based on the CT findings are noted.
The 10- and 5-mm sections from the same patient were interpreted separately by two fellowship-trained body imaging attending physicians (J.K., P.M.), each with several years experience in the interpretation of CT scans for appendicitis, who were blinded to the final results. The 10- and 5-mm sections were mixed and were shown to the blinded readers independently in two series of sessions over a 3-month period. The 10- and 5-mm sections from any single patient were shown to the blinded readers a minimum of 4 weeks apart. The readers were not blinded to the section thickness, as any experienced reader of CT scans easily could guess the section thickness by estimating the amount of z-axis coverage on a series of CT images.
The confidence in the diagnosis of acute appendicitis was graded as 1 if certainty was thought to be greater than 85%, as 2 if it was 40%–85%, or as 3 if it was less than 40%. Confidence grade 1, definite appendicitis, was given if an abnormal appendix or an appendicolith associated with periappendiceal inflammatory changes was seen; confidence grade 2, probable appendicitis, was given if right-lower-quadrant inflammatory changes, abscess, or cecal wall thickening was seen without identification of an abnormal appendix or appendicolith; and confidence grade 3, cannot rule out appendicitis, was given if equivocal findings for confidence grade 2 were seen. CT scans were interpreted as negative for appendicitis if a normal appendix was seen or if none of the previously mentioned findings was seen.
The authors also assessed the scans for technical quality, in particular for adequate opacification of the terminal ileum and the cecum with oral or rectal contrast material.
Patient Follow-up
The histopathology reports were reviewed in all patients in whom appendectomy or other surgical procedures were performed to verify the diagnosis of appendicitis. One patient with negative CT findings underwent appendectomy; the appendix was found to be normal at histopathologic examination.
Patients who did not undergo surgery, regardless of whether they were admitted to the hospital or discharged from the emergency department, were contacted to determine if surgery was performed elsewhere at a later date. Of the 51 patients who did not undergo surgery, 30 were examined at an outpatient clinic 1–2 months after the emergency department visit. The other 21 patients were contacted directly with a telephone call from the study's authors. If no surgery was performed and if the patients' symptoms resolved without antibiotics, the findings were also considered true-negative. Any alternate clinical diagnosis in the patient's chart also was recorded.
Statistical Analysis
All P values were calculated on the basis of the 
2 test results. A P value of .05 was considered to indicate a significant difference. Interobserver agreement was determined with 
statistics.
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RESULTS
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Forty-eight of 100 patients had histopathologically proved acute appendicitis. Findings in the remaining 52 patients were considered true-negative on the basis of the follow-up criteria. Three additional patients with negative CT findings had been excluded from the study. Their symptoms resolved after antibiotic treatment, and surgery was never performed. We could not determine whether the findings in these patients represented true- or false-negative findings.
Analysis of the data from the two blinded readers' interpretations of the 5- and 10-mm sections revealed higher sensitivity and accuracy with the 5-mm sections. An abnormal appendix, right-lower-quadrant inflammatory changes, an appendicolith, and cecal wall thickening were seen more frequently with 5-mm sections (Table 1). On the basis of the 2 test results, the calculated P value for sensitivity was less than .001; for accuracy, less than .001; and for specificity, .426 in a comparison of 5- and 10-mm sections. The interobserver agreement ( statistic) was 0.93 for 5-mm sections and was 0.84 for 10-mm sections.
One reader had eight and the other had nine false-negative findings when the 10-mm sections were interpreted. It is interesting that six of the findings were in the same patients. With the 5-mm sections, all of these false-negative findings were interpreted correctly as positive. However, one reader had one false-negative finding with the 5-mm sections that was interpreted as positive with the 10-mm sections. Retrospective review of this case showed a mildly dilated (7-mm-diameter) appendix and showed minimal periappendiceal inflammatory changes on 5- and 10-mm sections.
Each reader had one false-positive finding with 5-mm sections in one patient each. One patient had ileocolitis. The CT scan showed thickening of the terminal ileum and the cecum, and the normal appendix was difficult to visualize. Findings in this patient were interpreted as positive by the same reader with 10-mm sections. In the other patient, there was localized fluid at the caput cecum; the patient had torsion of an ovarian dermoid cyst at surgery. With 10-mm sections, one reader had false-positive findings in two patients, and the other had false-positive findings in three patients. One of the patients, in whom a terminal ileum with inadequate enteric contrast material opacification was mistaken for a dilated appendix, was the same for both readers. The other patients had right-sided diverticulitis, Crohn disease, or ileocolitis.
In the 52 patients without acute appendicitis, a normal appendix was identified in 39 (75%) with the 5-mm sections and in 27 (52%) with the 10-mm sections (P = .025). The interobserver agreement ( statistic) was 0.58 for the 5-mm sections and was 0.69 for the 10-mm sections. Of these patients, 46 (88%) had adequate cecal opacification from either the oral or rectal enteric contrast material. Of the 52 patients with negative findings, 28 (54%) had normal CT scans, and 24 (46%) had findings that demonstrated a variety of other diseases (Table 2). Ovarian cysts (in five patients) were the most common alternate diagnosis in this group.
The confidence level in the interpretation of appendicitis also was assessed (Table 3). Grade 1, grade 2, and grade 3 confidence levels in the diagnosis of acute appendicitis in the surgically proved cases were 92% and 71% (P = .019), 6% and 21%, and 2% and 8% with 5- and 10-mm-collimated sections, respectively. The interobserver agreement ( statistic) for the grade 1 confidence level was 0.95 for 5-mm sections and was 0.79 for 10-mm sections.
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DISCUSSION
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Analysis of the data in our prospective study reveals that 5-mm sections have many advantages over 10-mm sections. The use of 5-mm sections decreases partial volume artifact and allows the reader to follow structures on multiple consecutive sections. With 5-mm sections, 99% accuracy was achieved (89% accuracy with 10-mm sections), which is comparable with findings in investigations by Rao et al (12,13). With 10-mm sections, one reader had eight and the other had nine false-negative findings in 48 positive cases. The fact that six of these false-negative findings were in the same patients indicates strongly that abnormalities can be missed with 10-mm sections alone (Fig 1).
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Figure 1a. False-negative helical CT findings with 10-mm sections; the correct diagnosis was made with 5-mm sections. (a, b) Two contiguous, 10-mm-collimated transverse sections in the right lower quadrant reveal a prominent appendix without obvious dilatation of the lumen (arrow). Periappendiceal inflammation is not well seen. The blinded readers misdiagnosed this case as negative. (c, d) Two contiguous, 5-mm-collimated transverse sections obtained at the same level as a and b in the same patient demonstrate a dilated appendix (solid arrow) with periappendiceal inflammatory changes (open arrow in d). The readers' interpretations were positive for acute appendicitis.
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Figure 1b. False-negative helical CT findings with 10-mm sections; the correct diagnosis was made with 5-mm sections. (a, b) Two contiguous, 10-mm-collimated transverse sections in the right lower quadrant reveal a prominent appendix without obvious dilatation of the lumen (arrow). Periappendiceal inflammation is not well seen. The blinded readers misdiagnosed this case as negative. (c, d) Two contiguous, 5-mm-collimated transverse sections obtained at the same level as a and b in the same patient demonstrate a dilated appendix (solid arrow) with periappendiceal inflammatory changes (open arrow in d). The readers' interpretations were positive for acute appendicitis.
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Figure 1c. False-negative helical CT findings with 10-mm sections; the correct diagnosis was made with 5-mm sections. (a, b) Two contiguous, 10-mm-collimated transverse sections in the right lower quadrant reveal a prominent appendix without obvious dilatation of the lumen (arrow). Periappendiceal inflammation is not well seen. The blinded readers misdiagnosed this case as negative. (c, d) Two contiguous, 5-mm-collimated transverse sections obtained at the same level as a and b in the same patient demonstrate a dilated appendix (solid arrow) with periappendiceal inflammatory changes (open arrow in d). The readers' interpretations were positive for acute appendicitis.
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Figure 1d. False-negative helical CT findings with 10-mm sections; the correct diagnosis was made with 5-mm sections. (a, b) Two contiguous, 10-mm-collimated transverse sections in the right lower quadrant reveal a prominent appendix without obvious dilatation of the lumen (arrow). Periappendiceal inflammation is not well seen. The blinded readers misdiagnosed this case as negative. (c, d) Two contiguous, 5-mm-collimated transverse sections obtained at the same level as a and b in the same patient demonstrate a dilated appendix (solid arrow) with periappendiceal inflammatory changes (open arrow in d). The readers' interpretations were positive for acute appendicitis.
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With 5-mm sections, 98% specificity was achieved. There were two patients with false-positive findings (ileocolitis in one patient, and localized fluid at the caput cecum in the other) by two readers in this study. Balthazar et al (10) reported a specificity of 83% (30 of 36 cases) for appendicitis by using 5 x 8-mm collimation, with the patients receiving oral and intravenous contrast material. Rao et al (13) used CT with only rectal contrast material and scanned through the right lower quadrant with 5 x 5-mm sections; they reported a specificity of 98% (46 of 47 cases) for appendicitis. In our study, 92 (92%) patients received rectal contrast material in addition to oral and intravenous contrast material, which helped to achieve the specificity of 98% and which was especially helpful in differentiating appendicitis from diseases such as right-sided diverticulitis and ileocolitis.
The frequency of confidence grade 1 for the diagnosis was higher with 5-mm sections (92%) than with 10-mm sections (71%); this difference was significant (P = .019). Confidence grade 1 was given when the reader thought that appendicitis was definite; confidence grade 3 was given when the reader thought that acute appendicitis could not be excluded (Fig 2). We were not surprised to see a higher confidence level with 5-mm sections because of the higher rates in identifying each of the individual features of appendicitis, which included an abnormal appendix, inflammatory change, cecal wall thickening, and an appendicolith (Fig 3). Both readers had similar confidence levels ( = 0.95 for grade 1) with 5-mm sections, which indicates that they used similar criteria in grading their confidence levels.
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Figure 2a. Low confidence level with 10-mm sections and a high confidence level with 5-mm sections. (a, b) Two contiguous, 10-mm-collimated transverse helical CT scans of the right lower quadrant show questionable inflammatory changes (open arrow); the diagnostic confidence level was graded as 3 by the readers. A soft-tissue opacity (solid arrow in b) also is seen but cannot be identified as an appendix. (c, d) Two contiguous, 5-mm-collimated transverse helical CT scans obtained at the same level as a and b in the same patient show a dilated and contrast material-enhanced appendix (solid arrow) and periappendiceal, inflammatory changes (open arrow in d). These findings were identified definitely, and the diagnostic confidence level was graded as 1 by the readers.
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Figure 2b. Low confidence level with 10-mm sections and a high confidence level with 5-mm sections. (a, b) Two contiguous, 10-mm-collimated transverse helical CT scans of the right lower quadrant show questionable inflammatory changes (open arrow); the diagnostic confidence level was graded as 3 by the readers. A soft-tissue opacity (solid arrow in b) also is seen but cannot be identified as an appendix. (c, d) Two contiguous, 5-mm-collimated transverse helical CT scans obtained at the same level as a and b in the same patient show a dilated and contrast material-enhanced appendix (solid arrow) and periappendiceal, inflammatory changes (open arrow in d). These findings were identified definitely, and the diagnostic confidence level was graded as 1 by the readers.
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Figure 2c. Low confidence level with 10-mm sections and a high confidence level with 5-mm sections. (a, b) Two contiguous, 10-mm-collimated transverse helical CT scans of the right lower quadrant show questionable inflammatory changes (open arrow); the diagnostic confidence level was graded as 3 by the readers. A soft-tissue opacity (solid arrow in b) also is seen but cannot be identified as an appendix. (c, d) Two contiguous, 5-mm-collimated transverse helical CT scans obtained at the same level as a and b in the same patient show a dilated and contrast material-enhanced appendix (solid arrow) and periappendiceal, inflammatory changes (open arrow in d). These findings were identified definitely, and the diagnostic confidence level was graded as 1 by the readers.
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Figure 2d. Low confidence level with 10-mm sections and a high confidence level with 5-mm sections. (a, b) Two contiguous, 10-mm-collimated transverse helical CT scans of the right lower quadrant show questionable inflammatory changes (open arrow); the diagnostic confidence level was graded as 3 by the readers. A soft-tissue opacity (solid arrow in b) also is seen but cannot be identified as an appendix. (c, d) Two contiguous, 5-mm-collimated transverse helical CT scans obtained at the same level as a and b in the same patient show a dilated and contrast material-enhanced appendix (solid arrow) and periappendiceal, inflammatory changes (open arrow in d). These findings were identified definitely, and the diagnostic confidence level was graded as 1 by the readers.
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Figure 3a. Low and high sensitivity in the identification of individual features of acute appendicitis with 10- and 5-mm sections, respectively. (a, b) Two contiguous, 10-mm-collimated transverse, helical CT scans of the right lower quadrant. Although appendicitis was diagnosed correctly, the thickened cecal wall and appendicolith were not identified by the blinded readers. (c, d) Two contiguous, 5-mm-collimated transverse helical CT scans obtained at the same level as a and b in the same patient clearly show a thickened cecal wall (solid arrow in c), an appendicolith (open arrow in d), and inflammatory changes.
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Figure 3b. Low and high sensitivity in the identification of individual features of acute appendicitis with 10- and 5-mm sections, respectively. (a, b) Two contiguous, 10-mm-collimated transverse, helical CT scans of the right lower quadrant. Although appendicitis was diagnosed correctly, the thickened cecal wall and appendicolith were not identified by the blinded readers. (c, d) Two contiguous, 5-mm-collimated transverse helical CT scans obtained at the same level as a and b in the same patient clearly show a thickened cecal wall (solid arrow in c), an appendicolith (open arrow in d), and inflammatory changes.
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Figure 3c. Low and high sensitivity in the identification of individual features of acute appendicitis with 10- and 5-mm sections, respectively. (a, b) Two contiguous, 10-mm-collimated transverse, helical CT scans of the right lower quadrant. Although appendicitis was diagnosed correctly, the thickened cecal wall and appendicolith were not identified by the blinded readers. (c, d) Two contiguous, 5-mm-collimated transverse helical CT scans obtained at the same level as a and b in the same patient clearly show a thickened cecal wall (solid arrow in c), an appendicolith (open arrow in d), and inflammatory changes.
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Figure 3d. Low and high sensitivity in the identification of individual features of acute appendicitis with 10- and 5-mm sections, respectively. (a, b) Two contiguous, 10-mm-collimated transverse, helical CT scans of the right lower quadrant. Although appendicitis was diagnosed correctly, the thickened cecal wall and appendicolith were not identified by the blinded readers. (c, d) Two contiguous, 5-mm-collimated transverse helical CT scans obtained at the same level as a and b in the same patient clearly show a thickened cecal wall (solid arrow in c), an appendicolith (open arrow in d), and inflammatory changes.
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The use of a high diagnostic confidence level can help to avoid further work-up in the patient and can help to avoid delay in treatment. In particular, with the routine use of 10-mm sections, there is a tendency to interpret all right-lower-quadrant inflammatory change as possible appendicitis. The use of 5-mm sections allows superior delineation of the anatomy of the right lower quadrant, in particular the dilated appendix. This was especially important in light of the large number of alternate inflammatory right-lower-quadrant conditions seen in the patients in our series.
The identification of the normal appendix excludes appendicitis effectively with a greater degree of confidence than does the inability to identify CT signs of appendicitis. We have found that surgeons often ask whether the normal appendix was identified, as this increases their confidence in the negative predictive value of a negative CT report. A higher clinical confidence in radiologic diagnoses may affect clinical management. With 5- and 10-mm sections, normal appendices were identified in 75% and 52% of negative cases, respectively (P = .025) (Fig 4). Rao et al (13) reported a normal appendix on CT scans in 44 (94%) of 47 patients with negative findings. Since 88% of our 52 patients had contrast material opacification of the cecum, we do not believe that the use of rectal contrast material could account for the higher rates documented in their series. However, their data did include 13 patients in whom an additional decubitus series was obtained to clarify initial CT findings. In our study, no such additional scanning was performed. Lane et al (14) reported that 28 (67%) of 42 normal appendices were identified by using 5-mm, nonenhanced, helical CT; this finding was closer to our finding.
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Figure 4a. Improved visualization of the normal appendix. (a) Transverse, 10-mm-collimated helical CT scan of the right lower quadrant. The normal appendix was not seen. (b) Transverse, 5-mm-collimated helical CT scan obtained at the same level as a in the same patient shows the normal appendix (arrow), which was identified without difficulty. Identifying the normal appendix is important in excluding acute appendicitis.
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Figure 4b. Improved visualization of the normal appendix. (a) Transverse, 10-mm-collimated helical CT scan of the right lower quadrant. The normal appendix was not seen. (b) Transverse, 5-mm-collimated helical CT scan obtained at the same level as a in the same patient shows the normal appendix (arrow), which was identified without difficulty. Identifying the normal appendix is important in excluding acute appendicitis.
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In summary, comparisons of 5- and 10-mm sections in the same patient demonstrated that 5-mm sections have many advantages over 10-mm sections in the diagnosis of acute appendicitis. With 5-mm sections, there was a higher sensitivity and accuracy and a greater ability to identify the individual features of appendicitis. The diagnostic confidence level for appendicitis was higher with 5-mm sections; this can help to avoid delays in treatment. The more frequent identification of a normal appendix with 5-mm sections provided strong evidence to rule out acute appendicitis. Our study findings suggest that the use of thin sections improves the CT depiction of acute appendicitis.
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ACKNOWLEDGMENTS
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We are grateful to Dvorah Balsam, MD, Christos Carvounis, MD, and Leonard Rosenstein, PhD, for manuscript preparation and for assistance with statistical analysis. We also are grateful to the CT technologists in the department of radiology for making this study possible.
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FOOTNOTES
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Author contributions: Guarantors of integrity of entire study, D.I.W., P.M., J.Y.; study concepts and design, D.I.W., J.Y.; definition of intellectual content, D.I.W., J.Y.; literature research, D.I.W., J.Y.; clinical studies, D.I.W., J.Y., S.H.; data acquisition and analysis, D.I.W., P.M., J.K., J.Y.; statistical analysis, J.Y.; manuscript preparation, J.Y.; manuscript editing and review, D.I.W., J.Y., J.K.
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REFERENCES
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|---|
-
Jacob ET, Bar-Nathan N, Luchtman M. Error-rate factor in the management of appendicitis (letter). Lancet 1975; 2:1032.
-
Jess P, Bjerregaard B, Brynitz S, et al. Prospective trial concerning diagnostic accuracy and complications. Am J Surg 1981; 141:232-234.[Medline]
-
Berry J, Jr, Malt R. Appendicitis near its centenary. Ann Surg 1984; 200:567-575.[Medline]
-
Anderson RE, Hugander A, Thulin AJG. Diagnostic accuracy and perforation rate in appendicitis: association with age and sex of the patient and with appendectomy rate. Eur J Surg 1992; 158:37-41.[Medline]
-
Schuler JG, Shortsleeve MJ, Goldenson RS, et al. Is there a role for abdominal computed tomographic scans in appendicitis?. Arch Surg 1998; 133:373-376.[Abstract/Free Full Text]
-
Puylaert JBCM. Acute appendicitis: US evaluation using graded compression. Radiology 1986; 158:355-360.[Abstract/Free Full Text]
-
Rioux M. Sonographic detection of the normal and abnormal appendix. AJR Am J Roentgenol 1992; 158:773-778.[Abstract/Free Full Text]
-
Balthazar EJ, Birnbaum BA, Yee J, et al. Acute appendicitis: CT and US correlation in 100 patients. Radiology 1994; 190:31-35.[Abstract/Free Full Text]
-
Balthazar EJ, Megibow AJ, Hulnick D, et al. CT of appendicitis. AJR Am J Roentgenol 1986; 147:705-710.[Abstract/Free Full Text]
-
Balthazar EJ, Megibow AJ, Siegel SE, Birnbaum BA. Appendicitis: prospective evaluation with high-resolution CT. Radiology 1991; 180:21-24.[Abstract/Free Full Text]
-
Malone AJ, Wolf CR, Malmed AS, Melliere BF. Diagnosis of acute appendicitis: value of unenhanced CT. AJR Am J Roentgenol 1993; 160:763-766.[Abstract/Free Full Text]
-
Rao PM, Rhea JT, Novelline RA, et al. Helical CT technique for the diagnosis of appendicitis: prospective evaluation of a focused appendix CT examination. Radiology 1997; 202:139-144.[Abstract/Free Full Text]
-
Rao PM, Rhea JT, Novelline RA, et al. Helical CT combined with contrast material administered only through the colon for imaging of suspected appendicitis. AJR Am J Roentgenol 1997; 169:1275-1280.[Abstract/Free Full Text]
-
Lane MJ, Katz DS, Ross BA, et al. Unenhanced helical CT for suspected acute appendicitis. AJR Am J Roentgenol 1997; 168:405-409.[Abstract/Free Full Text]
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Am. J. Roentgenol.,
May 1, 2007;
188(5):
1313 - 1319.
[Abstract]
[Full Text]
[PDF]
|
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|
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E M Anderson and H K Bungay
Imaging investigation of acute right iliac fossa pain
Imaging,
December 1, 2006;
18(4):
257 - 267.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
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J. E. Jacobs
CT and Sonography for Suspected Acute Appendicitis: A Commentary.
Am. J. Roentgenol.,
April 1, 2006;
186(4):
1094 - 1096.
[Full Text]
[PDF]
|
|
|
|
|
|
|
T. Terasawa, C. C. Blackmore, S. Bent, and R. J. Kohlwes
Systematic Review: Computed Tomography and Ultrasonography To Detect Acute Appendicitis in Adults and Adolescents
Ann Intern Med,
October 5, 2004;
141(7):
537 - 546.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. Keyzer, D. Tack, V. de Maertelaer, P. Bohy, P. A. Gevenois, and D. Van Gansbeke
Acute Appendicitis: Comparison of Low-Dose and Standard-Dose Unenhanced Multi-Detector Row CT
Radiology,
July 1, 2004;
232(1):
164 - 172.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. M. Horrow, D. S. White, and J. C. Horrow
Differentiation of Perforated from Nonperforated Appendicitis at CT
Radiology,
April 1, 2003;
227(1):
46 - 51.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
E. K. Paulson, M. F. Kalady, and T. N. Pappas
Suspected Appendicitis
N. Engl. J. Med.,
January 16, 2003;
348(3):
236 - 242.
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. Alobaidi and A. Shirkhoda
Value of Bone Window Settings on CT for Revealing Appendicoliths in Patients with Appendicitis
Am. J. Roentgenol.,
January 1, 2003;
180(1):
201 - 205.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
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|
|
P J Shorvon
Imaging of appendicitis: a cautionary note
Br. J. Radiol.,
September 1, 2002;
75(897):
717 - 720.
[Full Text]
[PDF]
|
|
|
|
|
|
|
G Ege, H Akman, A Sahin, D Bugra, and K Kuzucu
Diagnostic value of unenhanced helical CT in adult patients with suspected acute appendicitis
Br. J. Radiol.,
September 1, 2002;
75(897):
721 - 725.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
T C See, C S Ng, C J E Watson, and A K Dixon
Appendicitis: spectrum of appearances on helical CT
Br. J. Radiol.,
September 1, 2002;
75(897):
775 - 781.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. W. Wise, M. R. Labuski, C. J. Kasales, J. S. Blebea, J. W. Meilstrup, G. P. Holley, S. A. LaRusso, J. Holliman, F. M. Ruggiero, and D. Mauger
Comparative Assessment of CT and Sonographic Techniques for Appendiceal Imaging
Am. J. Roentgenol.,
April 1, 2001;
176(4):
933 - 941.
[Abstract]
[Full Text]
[PDF]
|
|
|
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|
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R. Wijetunga, B. S. Tan, J. C. Rouse, G. W. Bigg-Wither, and B. D. Doust
Diagnostic Accuracy of Focused Appendiceal CT in Clinically Equivocal Cases of Acute Appendicitis
Radiology,
December 1, 2001;
221(3):
747 - 753.
[Abstract]
[Full Text]
[PDF]
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TOP
ABSTRACT
INTRODUCTION
