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Comparison of Imaging Strategies with Conditional versus Immediate Contrast-Enhanced Computed Tomography in Patients with Clinical Suspicion of Acute Appendicitis.

Atema JJ, Gans SL, Van Randen A, Laméris W, van Es HW, van Heesewijk JP, van Ramshorst B, Bouma WH, Ten Hove W, van Keulen EM, Dijkgraaf MG, Bossuyt PM, Stoker J, Boermeester MA - Eur Radiol (2015)

Bottom Line: An expert panel assigned a final diagnosis to each patient after 6 months of follow-up (clinical reference standard).The specificity of conditional CT imaging was lower: 77 % (95 %CI, 70 % to 83 %) versus 87 % for immediate CT (95 %CI, 81 % to 91 %).However, conditional CT imaging results in more false positives. • Conditional CT (CT after negative/inconclusive ultrasound findings) can be used for suspected appendicitis. • Half the number of CT examinations is needed with a conditional strategy. • Conditional CT correctly identifies as many patients with appendicitis as immediate CT. • Conditional imaging results in more false positive appendicitis cases.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery (G4-142), Academic Medical Centre, 1105 AZ, Amsterdam, Netherlands, j.j.atema@amc.nl.

ABSTRACT

Objectives: To compare the diagnostic accuracy of conditional computed tomography (CT), i.e. CT when initial ultrasound findings are negative or inconclusive, and immediate CT for patients with suspected appendicitis.

Methods: Data were collected within a prospective diagnostic accuracy study on imaging in adults with acute abdominal pain. All patients underwent ultrasound and CT, read by different observers who were blinded from the other modality. Only patients with clinical suspicion of appendicitis were included. An expert panel assigned a final diagnosis to each patient after 6 months of follow-up (clinical reference standard).

Results: A total of 422 patients were included with final diagnosis appendicitis in 251 (60 %). For 199 patients (47 %), ultrasound findings were inconclusive or negative. Conditional CT imaging correctly identified 241 of 251 (96 %) appendicitis cases (95 %CI, 92 % to 98 %), versus 238 (95 %) with immediate CT (95 %CI, 91 % to 97 %). The specificity of conditional CT imaging was lower: 77 % (95 %CI, 70 % to 83 %) versus 87 % for immediate CT (95 %CI, 81 % to 91 %).

Conclusion: A conditional CT strategy correctly identifies as many patients with appendicitis as an immediate CT strategy, and can halve the number of CTs needed. However, conditional CT imaging results in more false positives.

Key points: • Conditional CT (CT after negative/inconclusive ultrasound findings) can be used for suspected appendicitis. • Half the number of CT examinations is needed with a conditional strategy. • Conditional CT correctly identifies as many patients with appendicitis as immediate CT. • Conditional imaging results in more false positive appendicitis cases.

No MeSH data available.


Related in: MedlinePlus

Flowchart of the results of imaging strategies with (A) conditional CT and (B) immediate CT in patients with clinical suspicion of acute appendicitis
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Fig1: Flowchart of the results of imaging strategies with (A) conditional CT and (B) immediate CT in patients with clinical suspicion of acute appendicitis

Mentions: Flow charts of the findings of the conditional CT strategy and the immediate CT strategy are depicted in Fig. 1A and B. In 199 patients (47 %) ultrasound imaging was inconclusive or negative for appendicitis. The estimated diagnostic accuracy of both strategies is shown in Table 2. The conditional CT strategy was able to identify correctly a similar number of patients with acute appendicitis, compared to the immediate CT strategy: 241 (96 %; 95 %CI, 93 % to 98 %) versus 238 (95 %; 95 %CI, 91 % to 97 %) of 251. However, the conditional CT strategy resulted in more false positives compared to the immediate CT strategy (39 versus 22), with a lower specificity of 77 % (132 of 171; 95 %CI, 70 % to 83 %) versus 87 % (149 of 171; 95 %CI, 81 % to 91 %) and a lower positive predictive value of 86 % (95 %CI, 81 % to 90 %) versus 92 % (95 %CI, 87 % to 95 %). Comparison of the diagnostic performance of the direct CT and the conditional CT strategy based on likelihood ratios did not demonstrate superiority of one strategy.Fig. 1


Comparison of Imaging Strategies with Conditional versus Immediate Contrast-Enhanced Computed Tomography in Patients with Clinical Suspicion of Acute Appendicitis.

Atema JJ, Gans SL, Van Randen A, Laméris W, van Es HW, van Heesewijk JP, van Ramshorst B, Bouma WH, Ten Hove W, van Keulen EM, Dijkgraaf MG, Bossuyt PM, Stoker J, Boermeester MA - Eur Radiol (2015)

Flowchart of the results of imaging strategies with (A) conditional CT and (B) immediate CT in patients with clinical suspicion of acute appendicitis
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4495262&req=5

Fig1: Flowchart of the results of imaging strategies with (A) conditional CT and (B) immediate CT in patients with clinical suspicion of acute appendicitis
Mentions: Flow charts of the findings of the conditional CT strategy and the immediate CT strategy are depicted in Fig. 1A and B. In 199 patients (47 %) ultrasound imaging was inconclusive or negative for appendicitis. The estimated diagnostic accuracy of both strategies is shown in Table 2. The conditional CT strategy was able to identify correctly a similar number of patients with acute appendicitis, compared to the immediate CT strategy: 241 (96 %; 95 %CI, 93 % to 98 %) versus 238 (95 %; 95 %CI, 91 % to 97 %) of 251. However, the conditional CT strategy resulted in more false positives compared to the immediate CT strategy (39 versus 22), with a lower specificity of 77 % (132 of 171; 95 %CI, 70 % to 83 %) versus 87 % (149 of 171; 95 %CI, 81 % to 91 %) and a lower positive predictive value of 86 % (95 %CI, 81 % to 90 %) versus 92 % (95 %CI, 87 % to 95 %). Comparison of the diagnostic performance of the direct CT and the conditional CT strategy based on likelihood ratios did not demonstrate superiority of one strategy.Fig. 1

Bottom Line: An expert panel assigned a final diagnosis to each patient after 6 months of follow-up (clinical reference standard).The specificity of conditional CT imaging was lower: 77 % (95 %CI, 70 % to 83 %) versus 87 % for immediate CT (95 %CI, 81 % to 91 %).However, conditional CT imaging results in more false positives. • Conditional CT (CT after negative/inconclusive ultrasound findings) can be used for suspected appendicitis. • Half the number of CT examinations is needed with a conditional strategy. • Conditional CT correctly identifies as many patients with appendicitis as immediate CT. • Conditional imaging results in more false positive appendicitis cases.

View Article: PubMed Central - PubMed

Affiliation: Department of Surgery (G4-142), Academic Medical Centre, 1105 AZ, Amsterdam, Netherlands, j.j.atema@amc.nl.

ABSTRACT

Objectives: To compare the diagnostic accuracy of conditional computed tomography (CT), i.e. CT when initial ultrasound findings are negative or inconclusive, and immediate CT for patients with suspected appendicitis.

Methods: Data were collected within a prospective diagnostic accuracy study on imaging in adults with acute abdominal pain. All patients underwent ultrasound and CT, read by different observers who were blinded from the other modality. Only patients with clinical suspicion of appendicitis were included. An expert panel assigned a final diagnosis to each patient after 6 months of follow-up (clinical reference standard).

Results: A total of 422 patients were included with final diagnosis appendicitis in 251 (60 %). For 199 patients (47 %), ultrasound findings were inconclusive or negative. Conditional CT imaging correctly identified 241 of 251 (96 %) appendicitis cases (95 %CI, 92 % to 98 %), versus 238 (95 %) with immediate CT (95 %CI, 91 % to 97 %). The specificity of conditional CT imaging was lower: 77 % (95 %CI, 70 % to 83 %) versus 87 % for immediate CT (95 %CI, 81 % to 91 %).

Conclusion: A conditional CT strategy correctly identifies as many patients with appendicitis as an immediate CT strategy, and can halve the number of CTs needed. However, conditional CT imaging results in more false positives.

Key points: • Conditional CT (CT after negative/inconclusive ultrasound findings) can be used for suspected appendicitis. • Half the number of CT examinations is needed with a conditional strategy. • Conditional CT correctly identifies as many patients with appendicitis as immediate CT. • Conditional imaging results in more false positive appendicitis cases.

No MeSH data available.


Related in: MedlinePlus