### Abstract

Objective: Our objective was to evaluate the diagnostic value of computed tomography angiography (CTA) and ventilation perfusion (V/Q) scan in the assessment of pulmonary embolism (PE) by means of a Bayesian statistical model. Methods: Wells criteria defined pretest probability. Sensitivity and specificity of CTA and V/Q scan for PE were derived from pooled meta-analysis data. Likelihood ratios calculated for CTA and V/Q were inserted in the nomogram. Absolute (ADG) and relative diagnostic gains (RDG) were analyzed comparing post- and pretest probability. Comparative gain difference was calculated for CTA ADG over V/Q scan integrating ANOVA p value set at 0.05. Results: The sensitivity for CT was 86.0% (95% CI: 80.2%, 92.1%) and specificity of 93.7% (95% CI: 91.1%, 96.3%). The V/Q scan yielded a sensitivity of 96% (95% CI: 95%, 97%) and a specificity of 97% (95% CI: 96%, 98%). Bayes nomogram results for CTA were low risk and yielded a posttest probability of 71.1%, an ADG of 56.1%, and an RDG of 374%, moderate-risk posttest probability was 85.1%, an ADG of 56.1%, and an RDG of 193.4%, and high-risk posttest probability was 95.2%, an ADG of 36.2%, and an RDG of 61.35%. The comparative gain difference for low-risk population was 46.1%; in moderate-risk 41.6%; and in high-risk a 22.1% superiority. ANOVA analysis for LR+ and LR− showed no significant difference (p = 0.8745, p = 0.9841 respectively). Conclusions: This Bayesian model demonstrated a superiority of CTA when compared to V/Q scan for the diagnosis of pulmonary embolism. Low-risk patients are recognized to have a superior overall comparative gain favoring CTA.

Original language | English (US) |
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Pages (from-to) | 355-359 |

Number of pages | 5 |

Journal | Emergency Radiology |

Volume | 24 |

Issue number | 4 |

DOIs | |

State | Published - Aug 1 2017 |

Externally published | Yes |

### Keywords

- Bayesian model
- CT angiography
- Pulmonary embolism
- V/Q scan

### ASJC Scopus subject areas

- Emergency Medicine
- Radiology Nuclear Medicine and imaging

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## Cite this

*Emergency Radiology*,

*24*(4), 355-359. https://doi.org/10.1007/s10140-017-1486-6